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Sample records for p-gp protein expression

  1. Mini-P-gp and P-gp Co-Expression in Brown Trout Erythrocytes: A Prospective Blood Biomarker of Aquatic Pollution

    PubMed Central

    Valton, Emeline; Amblard, Christian; Desmolles, François; Combourieu, Bruno; Penault-Llorca, Frédérique; Bamdad, Mahchid

    2015-01-01

    In aquatic organisms, such as fish, blood is continually exposed to aquatic contaminants. Multidrug Resistance (MDR) proteins are ubiquitous detoxification membrane pumps, which recognize various xenobiotics. Moreover, their expression is induced by a large class of drugs and pollutants. We have highlighted the co-expression of a mini P-gp of 75 kDa and a P-gp of 140 kDa in the primary culture of brown trout erythrocytes and in the erythrocytes of wild brown trout collected from three rivers in the Auvergne region of France. In vitro experiments showed that benzo[a]pyrene, a highly toxic pollutant model, induced the co-expression of mini-P-gp and P-gp in trout erythrocytes in a dose-dependent manner and relay type response. Similarly, in the erythrocytes of wild brown trout collected from rivers contaminated by a mixture of PAH and other multi-residues of pesticides, mini-P-gp and P-gp were able to modulate their expression, according to the nature of the pollutants. The differential and complementary responses of mini-P-gp and P-gp in trout erythrocytes suggest the existence in blood cells of a real protective network against xenobiotics/drugs. This property could be exploited to develop a blood biomarker of river pollution. PMID:26854141

  2. In vitro and in vivo evaluation of the effects of piperine on P-gp function and expression

    SciTech Connect

    Han Yi; Chin Tan, Theresa May; Lim, Lee-Yong

    2008-08-01

    Piperine, a major component of black pepper, is used as spice and nutrient enhancer. The purpose of the present study was to evaluate the effects of acute and prolonged piperine exposure on cellular P-gp expression and function in vitro and in vivo. Piperine at concentrations ranging from 10 to 100 {mu}M, determined by MTT assay to be non-cytotoxic, was observed to inhibit P-gp mediated efflux transport of [{sup 3}H]-digoxin across L-MDR1 and Caco-2 cell monolayers. The acute inhibitory effect was dependent on piperine concentration, with abolishment of [{sup 3}H]-digoxin polarized transport attained at 50 {mu}M of piperine. In contrast, prolonged (48 and 72 h) co-incubation of Caco-2 cell monolayers with piperine (50 and 100 {mu}M) increased P-gp activity through an up-regulation of cellular P-gp protein and MDR1 mRNA levels. The up-regulated protein was functionally active, as demonstrated by a higher degree of [{sup 3}H]-digoxin efflux across the cell monolayers, but the induction was readily reversed by the removal of the spice from the culture medium. Peroral administration of piperine at the dose of 112 {mu}g/kg body weight/day to male Wistar rats for 14 consecutive days also led to increased intestinal P-gp levels. However, there was a concomitant reduction in the rodent liver P-gp although the kidney P-gp level was unaffected. Our data suggest that caution should be exercised when piperine is to be co-administered with drugs that are P-gp substrates, particularly for patients whose diet relies heavily on pepper.

  3. P-gp expression in brown trout erythrocytes: evidence of a detoxification mechanism in fish erythrocytes

    PubMed Central

    Valton, Emeline; Amblard, Christian; Wawrzyniak, Ivan; Penault-Llorca, Frederique; Bamdad, Mahchid

    2013-01-01

    Blood is a site of physiological transport for a great variety of molecules, including xenobiotics. Blood cells in aquatic vertebrates, such as fish, are directly exposed to aquatic pollution. P-gp are ubiquitous “membrane detoxification proteins” implicated in the cellular efflux of various xenobiotics, such as polycyclic aromatic hydrocarbons (PAHs), which may be pollutants. The existence of this P-gp detoxification system inducible by benzo [a] pyrene (BaP), a highly cytotoxic PAH, was investigated in the nucleated erythrocytes of brown trout. Western blot analysis showed the expression of a 140-kDa P-gp in trout erythrocytes. Primary cultures of erythrocytes exposed to increasing concentrations of BaP showed no evidence of cell toxicity. Yet, in the same BaP-treated erythrocytes, P-gp expression increased significantly in a dose-dependent manner. Brown trout P-gp erythrocytes act as membrane defence mechanism against the pollutant, a property that can be exploited for future biomarker development to monitor water quality. PMID:24305632

  4. Dasatinib reverses the multidrug resistance of breast cancer MCF-7 cells to doxorubicin by downregulating P-gp expression via inhibiting the activation of ERK signaling pathway

    PubMed Central

    Chen, Ting; Wang, Changyuan; Liu, Qi; Meng, Qiang; Sun, Huijun; Huo, Xiaokui; Sun, Pengyuan; Peng, Jinyong; Liu, Zhihao; Yang, Xiaobo; Liu, Kexin

    2015-01-01

    Multidrug resistance (MDR) is one of the major obstacles to the efficiency of cancer chemotherapy, which often results from the overexpression of drug efflux transporters such as P-glycoprotein (P-gp). In the present study, we determined the effect of dasatinib which was approved for imatinib resistant chronic myelogenous leukemia (CML) and (Ph+) acute lymphoblastic leukemia (ALL) treatment on P-gp-mediated MDR. Our results showed that dasatinib significantly increased the sensitivity of P-gp-overexpressing MCF-7/Adr cells to doxorubicin in MTT assays; thus lead to an enhanced cytotoxicity of doxorubicin in MCF-7/Adr cells. Additionally, dasatinib increased the intracellular accumulation, inhibited the efflux of doxorubicin in MCF-7/Adr cells, and significantly enhanced doxorubicin-induced apoptosis in MCF-7/Adr cells. Further studies showed that dasatinib altered the expression levels of mRNA, protein levels of P-gp, and the phosphorylation of signal–regulated kinase (ERK) both in time-dependent (before 24 h) and dose-dependent manners at concentrations that produced MDR reversals. In conclusion, dasatinib reverses P-gp-mediated MDR by downregulating P-gp expression, which may be partly attributed to the inhibition of ERK pathway. Dasatinib may play an important role in circumventing MDR when combined with other conventional antineoplastic drugs. PMID:25482933

  5. Expression of HIF-1α and P-gp in non-small cell lung cancer and the relationship with HPV infection

    PubMed Central

    Lu, Yimin; Yu, Le-Qun; Zhu, Lixia; Zhao, Nian; Zhou, Xing-Ju; Lu, Xudong

    2016-01-01

    The aim of the study was to study the expression of hypoxia-inducible factor-1α (HIF-1α) and P-glycoprotein (P-gp) and analyze its correlation with human papillomavirus (HPV) infection. From January, 2012 to May, 2014, 72 cases of non-small cell lung cancer (NSCLC) pathologic tissue samples were selected from the study group. Fifty-four lung benign lesions were selected to serve as the control group. HIF-1α and P-gp expression levels were detected using immunohistochemistry. PCR was used to detect the expression of HPV genome employing specific primers for HPV 16 and 18 types. The results showed that there was 47.2 and 63.9% positive HIF-1α and P-gp expression in the study group. No P-gp or HIF-1α expression was detected in the control group. The results established a positive correlation between the expression of HIF-1α and P-gp. In the study group, the expression and differentiation degree of HIF-1α was related to lymphatic metastasis. The HIF-1α expression in the well-differentiated samples was lower than that in the moderate or poorly differentiated samples. HIF-1α expression in patients with lymphatic metastasis was higher than in patients without metastasis. The expression rate of P-gp in adenocarcinoma was higher than that in squamous carcinoma. The detection rate of HPV DNA was 45.83 and 3.70% in the study and control groups, respectively. The HPV infection and differentiation degree had relevance to lymphatic metastasis in the study group. The HPV DNA detection rate in the well-differentiated samples was lower than that in the moderate or poorly differentiated samples. The HPV DNA detection rate in patients with lymphatic metastasis was higher than that in patients with no lymphatic metastasis. There was a close link between HIF-1α, P-gp expression and NSCLC occurrence, and the development of multidrug resistance. In conclusion, the detection of HIF-1α and P-gp expression can effectively predict drug resistance during chemotherapy in NSCLC, and

  6. Validation of a P-Glycoprotein (P-gp) Humanized Mouse Model by Integrating Selective Absolute Quantification of Human MDR1, Mouse Mdr1a and Mdr1b Protein Expressions with In Vivo Functional Analysis for Blood-Brain Barrier Transport

    PubMed Central

    Sadiq, Muhammad Waqas; Uchida, Yasuo; Hoshi, Yutaro; Tachikawa, Masanori; Terasaki, Tetsuya; Hammarlund-Udenaes, Margareta

    2015-01-01

    It is essential to establish a useful validation method for newly generated humanized mouse models. The novel approach of combining our established species-specific protein quantification method combined with in vivo functional studies is evaluated to validate a humanized mouse model of P-gp/MDR1 efflux transporter. The P-gp substrates digoxin, verapamil and docetaxel were administered to male FVB Mdr1a/1b(+/+) (FVB WT), FVB Mdr1a/1b(-/-) (Mdr1a/1b(-/-)), C57BL/6 Mdr1a/1b(+/+) (C57BL/6 WT) and humanized C57BL (hMDR1) mice. Brain-to-plasma total concentration ratios (Kp) were measured. Quantitative targeted absolute proteomic (QTAP) analysis was used to selectively quantify the protein expression levels of hMDR1, Mdr1a and Mdr1b in the isolated brain capillaries. The protein expressions of other transporters, receptors and claudin-5 were also quantified. The Kp for digoxin, verapamil, and docetaxel were 20, 30 and 4 times higher in the Mdr1a/1b(-/-) mice than in the FVB WT controls, as expected. The Kp for digoxin, verapamil and docetaxel were 2, 16 and 2-times higher in the hMDR1 compared to the C57BL/6 WT mice. The hMDR1 mice had 63- and 9.1-fold lower expressions of the hMDR1 and Mdr1a proteins than the corresponding expression of Mdr1a in C57BL/6 WT mice, respectively. The protein expression levels of other molecules were almost consistent between C57BL/6 WT and hMDR1 mice. The P-gp function at the BBB in the hMDR1 mice was smaller than that in WT mice due to lower protein expression levels of hMDR1 and Mdr1a. The combination of QTAP and in vivo functional analyses was successfully applied to validate the humanized animal model and evaluates its suitability for further studies. PMID:25932627

  7. Transport Inhibition of Digoxin Using Several Common P-gp Expressing Cell Lines Is Not Necessarily Reporting Only on Inhibitor Binding to P-gp

    PubMed Central

    Lumen, Annie Albin; Li, Libin; Li, Jiben; Ahmed, Zeba; Meng, Zhou; Owen, Albert; Ellens, Harma; Hidalgo, Ismael J.; Bentz, Joe

    2013-01-01

    We have reported that the P-gp substrate digoxin required basolateral and apical uptake transport in excess of that allowed by digoxin passive permeability (as measured in the presence of GF120918) to achieve the observed efflux kinetics across MDCK-MDR1-NKI (The Netherlands Cancer Institute) confluent cell monolayers. That is, GF120918 inhibitable uptake transport was kinetically required. Therefore, IC50 measurements using digoxin as a probe substrate in this cell line could be due to inhibition of P-gp, of digoxin uptake transport, or both. This kinetic analysis is now extended to include three additional cell lines: MDCK-MDR1-NIH (National Institute of Health), Caco-2 and CPT-B2 (Caco-2 cells with BCRP knockdown). These cells similarly exhibit GF120918 inhibitable uptake transport of digoxin. We demonstrate that inhibition of digoxin transport across these cell lines by GF120918, cyclosporine, ketoconazole and verapamil is greater than can be explained by inhibition of P-gp alone. We examined three hypotheses for this non-P-gp inhibition. The inhibitors can: (1) bind to a basolateral digoxin uptake transporter, thereby inhibiting digoxin's cellular uptake; (2) partition into the basolateral membrane and directly reduce membrane permeability; (3) aggregate with digoxin in the donor chamber, thereby reducing the free concentration of digoxin, with concomitant reduction in digoxin uptake. Data and simulations show that hypothesis 1 was found to be uniformly acceptable. Hypothesis 2 was found to be uniformly unlikely. Hypothesis 3 was unlikely for GF120918 and cyclosporine, but further studies are needed to completely adjudicate whether hetero-dimerization contributes to the non-P-gp inhibition for ketoconazole and verapamil. We also find that P-gp substrates with relatively low passive permeability such as digoxin, loperamide and vinblastine kinetically require basolateral uptake transport over that allowed by +GF120918 passive permeability, while highly permeable

  8. Expression of P-gp, MRP, LRP, GST-π and TopoIIα and intrinsic resistance in human lung cancer cell lines.

    PubMed

    Wang, Jiarui; Zhang, Jinhui; Zhang, Lichuan; Zhao, Long; Fan, Sufang; Yang, Zhonghai; Gao, Fei; Kong, Ying; Xiao, Gary Guishan; Wang, Qi

    2011-11-01

    This study aimed to determine the relationship between the endogenous levels of P-glycoprotein (P-gp), multidrug resistance-associated protein (MRP), lung resistance-related protein (LRP), glutathione-s-transferase-π (GST‑π) and topoisomerase IIα (TopoIIα) and intrinsic drug resistance in four human lung cancer cell lines, SK-MES-1, SPCA-1, NCI-H-460 and NCI-H-446, of different histological types. The expression of P-gp, MRP, LRP, GST-π and TopoIIα was measured by immunofluorescence, Western blotting and RT-PCR. Drug resistance to cisplatin, doxorubicin and VP-16 was determined using MTT assays. The correlation between expression of the resistance-related proteins and their roles in the resistance to drugs in these cancer cell lines was analyzed. We found that the endogenous levels of P-gp, MRP, LRP, GST-π and TopoIIα in the four cell lines varied. The level of GST-π in the SK-MES-1 cells was the highest, whereas the level of P-gp in the SPCA-1 cells was the lowest. The chemoresistance to cisplatin, doxorubicin and VP-16 in the four cell lines was different. The SPCA-1 cell line was most resistance to cisplatin; SK-MES-1 was most resistance to VP-16; whereas SK-MES-1 was most sensitive to doxorubicin. There was a positive correlation between GST-π expression and resistance to cisplatin, between TopoIIα expression and resistance to VP-16; and a negative correlation was noted between TopoIIα expression and resistance to doxorubicin. In summary, the endogenous expression of P-gp, MRP, LRP, GST-π and TopoIIα was different in the four human lung cancer cell lines of different histological types, and this variance may be associated with the variation in chemosensitivity to cisplatin, doxorubicin and VP-16. Among the related proteins, GST-π may be useful for the prediction of the intrinsic resistance to cisplatin, whereas TopoIIα may be useful to predict resistance to doxorubicin and VP-16 in human lung cancer cell lines. PMID:21805041

  9. Subtle Structural Differences Trigger Inhibitory Activity of Propafenone Analogues at the Two Polyspecific ABC Transporters: P-Glycoprotein (P-gp) and Breast Cancer Resistance Protein (BCRP).

    PubMed

    Schwarz, Theresa; Montanari, Floriane; Cseke, Anna; Wlcek, Katrin; Visvader, Lene; Palme, Sarah; Chiba, Peter; Kuchler, Karl; Urban, Ernst; Ecker, Gerhard F

    2016-06-20

    The transmembrane ABC transporters P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) are widely recognized for their role in cancer multidrug resistance and absorption and distribution of compounds. Furthermore, they are linked to drug-drug interactions and toxicity. Nevertheless, due to their polyspecificity, a molecular understanding of the ligand-transporter interaction, which allows designing of both selective and dual inhibitors, is still in its infancy. This study comprises a combined approach of synthesis, in silico prediction, and in vitro testing to identify molecular features triggering transporter selectivity. Synthesis and testing of a series of 15 propafenone analogues with varied rigidity and basicity of substituents provide first trends for selective and dual inhibitors. Results indicate that both the flexibility of the substituent at the nitrogen atom, as well as the basicity of the nitrogen atom, trigger transporter selectivity. Furthermore, inhibitory activity of compounds at P-gp seems to be much more influenced by logP than those at BCRP. Exploiting these differences further should thus allow designing specific inhibitors for these two polyspecific ABC-transporters. PMID:26970257

  10. Evaluating Potential P-gp Substrates: Main Aspects to Choose the Adequate Permeability Model for Assessing Gastrointestinal Drug Absorption.

    PubMed

    da Silva Junior, João Batista; Dezani, Thaisa Marinho; Dezani, André Bersani; dos Reis Serra, Cristina Helena

    2015-01-01

    The success of an oral drug route administration depends on many factors that interfere in its bioavailability, therapeutic efficacy and clinical safety. In human cells, ATP-dependent efflux transporter proteins, such as P-glycoprotein (P-gp), BCRP and MRP2, reduce the absorption of drugs. A tiered approach chosen to evaluate drugs as substrates or inhibitors of efflux pumps, particularly P-gp, should be carefully selected, since each study method has advantages and intrinsic limitations to their processes. Depending on the adopted study conditions, the results may not correspond to the real characteristics of the drug regarding to its modulation by specific efflux proteins. This mini-review aims at summarizing the role of P-gp in the drugs oral absorption and correlating some of the most used permeability methods to determine the drug condition as P-gp substrate. Studies about P-gp have shown that it is a dynamic protein, facilitating secretion of endogenous compounds, as aldosterone, and protecting cells against xenobiotics. Different efflux assays are employed to evaluate drugs as P-gp substrates. In an initial planning, MDCK-MDR1 tend to be the chosen method for efflux studies due its ability of express P-gp, followed by studies conducted in Caco-2 models. However, it is necessary to evaluate the advantages and disadvantages of each method to generate sound results and to set the correlation in vitro x in situ x in vivo. PMID:25963568

  11. Co-administration strategy to enhance brain accumulation of vandetanib by modulating P-glycoprotein (P-gp/Abcb1) and breast cancer resistance protein (Bcrp1/Abcg2) mediated efflux with m-TOR inhibitors.

    PubMed

    Minocha, Mukul; Khurana, Varun; Qin, Bin; Pal, Dhananjay; Mitra, Ashim K

    2012-09-15

    The objectives of this study were (i) to characterize the interaction of vandetanib with P-glycoprotein (P-gp) and breast cancer resistance protein (Bcrp1) in vitro and in vivo (ii) to study the modulation of P-gp and BCRP mediated efflux of vandetanib with specific transport inhibitors and m-TOR inhibitors, everolimus and temsirolimus. Cellular accumulation and bi-directional transport studies in MDCKII cell monolayers were conducted to delineate the role of efflux transporters on disposition of vandetanib. Brain distribution studies were conducted in male FVB wild-type mice with vandetanib administered intravenously either alone or in the presence of specific inhibitors and m-TOR inhibitors. In vitro studies suggested that vandetanib is a high affinity substrate of Bcrp1 but is not transported by P-gp. Interestingly, in vivo brain distribution studies in FVB wild type mice indicated that vandetanib penetration into the brain is restricted by both Bcrp1 and P-gp mediated active efflux at the blood brain barrier (BBB). Co-administration of elacridar, a dual P-gp/BCRP inhibitor increased the brain to plasma concentration ratio of vandetanib upto 5 fold. Of the two m-TOR pathway inhibitors examined; everolimus showed potent effect on modulating vandetanib brain penetration whereas no significant affect on vandetanib brain uptake was observed following temsirolimus co-administration. This finding could be clinically relevant as everolimus can provide synergistic pharmacological effect in addition to primary role of vandetanib efflux modulation at BBB for the treatment of brain tumors. PMID:22633931

  12. Alternation of adriamycin penetration kinetics in MCF-7 cells from 2D to 3D culture based on P-gp expression through the Chk2/p53/NF-κB pathway.

    PubMed

    Lu, Meng; Zhou, Fang; Hao, Kun; Liu, Jiali; Chen, Qianying; Ni, Ping; Zhou, Honghao; Wang, Guangji; Zhang, Jingwei

    2015-01-15

    Monolayer cells are largely different from tumor masses, and might misguide drug screenings. 3D in vitro cell culture models simulate the characteristics of tumor masses in vivo and have recently been used in many studies of anti-cancer drugs. Among various 3D cell culture models, multi-cellular layer (MCL) models allow for the direct quantitative assessment of the penetration of chemotherapeutic agents through solid tissue environments without requiring the use of fluorescently labeled drugs or imaging molecules. Therefore, in our present study, a 3D-no base and embedded MCF-7 MCL model was successfully developed for a 14-day culture. Over time, its thickness and cell layers increased and exhibited highly proliferative properties and drug resistance to adriamycin (ADR) with markedly elevated IC50 values. Meanwhile, G2/M stage cycle arrest was also observed, which likely up-regulated P-gp expression through the Chk2/p53/NF-κB pathway. The elevated P-gp expression altered the ADR penetration kinetics in MCF-7 MCLs in vitro by accelerating the apparent penetration of ADR through the intercellular spaces of the MCLs. Additionally, a decreased ADR retention within tumor cells was observed, but could be significantly reversed by a P-gp inhibitor. The attenuated ADR retention in the deeper cells of tumor masses was confirmed in xenografted mice in vivo. This phenomenon could be elucidated by the mathematical modeling of penetration kinetics parameters. Our study provided a new model that evaluated and improved the quantification of the drug penetration kinetics, revealed the relationship between P-gp and drug penetration through tumor masses, and suggested the potential molecular mechanisms. PMID:25478729

  13. ABC transporters P-gp and Bcrp do not limit the brain uptake of the novel antipsychotic and anticonvulsant drug cannabidiol in mice.

    PubMed

    Brzozowska, Natalia; Li, Kong M; Wang, Xiao Suo; Booth, Jessica; Stuart, Jordyn; McGregor, Iain S; Arnold, Jonathon C

    2016-01-01

    Cannabidiol (CBD) is currently being investigated as a novel therapeutic for the treatment of CNS disorders like schizophrenia and epilepsy. ABC transporters such as P-glycoprotein (P-gp) and breast cancer resistance protein (Bcrp) mediate pharmacoresistance in these disorders. P-gp and Bcrp are expressed at the blood brain barrier (BBB) and reduce the brain uptake of substrate drugs including various antipsychotics and anticonvulsants. It is therefore important to assess whether CBD is prone to treatment resistance mediated by P-gp and Bcrp. Moreover, it has become common practice in the drug development of CNS agents to screen against ABC transporters to help isolate lead compounds with optimal pharmacokinetic properties. The current study aimed to assess whether P-gp and Bcrp impacts the brain transport of CBD by comparing CBD tissue concentrations in wild-type (WT) mice versus mice devoid of ABC transporter genes. P-gp knockout (Abcb1a/b (-∕-)), Bcrp knockout (Abcg2 (-∕-)), combined P-gp/Bcrp knockout (Abcb1a/b (-∕-) Abcg2 (-∕-)) and WT mice were injected with CBD, before brain and plasma samples were collected at various time-points. CBD results were compared with the positive control risperidone and 9-hydroxy risperidone, antipsychotic drugs that are established ABC transporter substrates. Brain and plasma concentrations of CBD were not greater in P-gp, Bcrp or P-gp/Bcrp knockout mice than WT mice. In comparison, the brain/plasma concentration ratios of risperidone and 9-hydroxy risperidone were profoundly higher in P-gp knockout mice than WT mice. These results suggest that CBD is not a substrate of P-gp or Bcrp and may be free from the complication of reduced brain uptake by these transporters. Such findings provide favorable evidence for the therapeutic development of CBD in the treatment of various CNS disorders. PMID:27257556

  14. ABC transporters P-gp and Bcrp do not limit the brain uptake of the novel antipsychotic and anticonvulsant drug cannabidiol in mice

    PubMed Central

    Brzozowska, Natalia; Li, Kong M.; Wang, Xiao Suo; Booth, Jessica; Stuart, Jordyn; McGregor, Iain S.

    2016-01-01

    Cannabidiol (CBD) is currently being investigated as a novel therapeutic for the treatment of CNS disorders like schizophrenia and epilepsy. ABC transporters such as P-glycoprotein (P-gp) and breast cancer resistance protein (Bcrp) mediate pharmacoresistance in these disorders. P-gp and Bcrp are expressed at the blood brain barrier (BBB) and reduce the brain uptake of substrate drugs including various antipsychotics and anticonvulsants. It is therefore important to assess whether CBD is prone to treatment resistance mediated by P-gp and Bcrp. Moreover, it has become common practice in the drug development of CNS agents to screen against ABC transporters to help isolate lead compounds with optimal pharmacokinetic properties. The current study aimed to assess whether P-gp and Bcrp impacts the brain transport of CBD by comparing CBD tissue concentrations in wild-type (WT) mice versus mice devoid of ABC transporter genes. P-gp knockout (Abcb1a/b−∕−), Bcrp knockout (Abcg2−∕−), combined P-gp/Bcrp knockout (Abcb1a/b−∕−Abcg2−∕−) and WT mice were injected with CBD, before brain and plasma samples were collected at various time-points. CBD results were compared with the positive control risperidone and 9-hydroxy risperidone, antipsychotic drugs that are established ABC transporter substrates. Brain and plasma concentrations of CBD were not greater in P-gp, Bcrp or P-gp/Bcrp knockout mice than WT mice. In comparison, the brain/plasma concentration ratios of risperidone and 9-hydroxy risperidone were profoundly higher in P-gp knockout mice than WT mice. These results suggest that CBD is not a substrate of P-gp or Bcrp and may be free from the complication of reduced brain uptake by these transporters. Such findings provide favorable evidence for the therapeutic development of CBD in the treatment of various CNS disorders. PMID:27257556

  15. The putative P-gp inhibitor telmisartan does not affect the transcellular permeability and cellular uptake of the calcium channel antagonist verapamil in the P-glycoprotein expressing cell line MDCK II MDR1

    PubMed Central

    Saaby, Lasse; Tfelt-Hansen, Peer; Brodin, Birger

    2015-01-01

    Verapamil is used in high doses for the treatment of cluster headache. Verapamil has been described as a P-glycoprotein (P-gp, ABCB1) substrate. We wished to evaluate in vitro whether co administration of a P-gp inhibitor with verapamil could be a feasible strategy for increasing CNS uptake of verapamil. Fluxes of radiolabelled verapamil across MDCK II MDR1 monolayers were measured in the absence and presence of the putative P-gp inhibitor telmisartan (a clinically approved drug compound). Verapamil displayed a vectorial basolateral-to-apical transepithelial efflux across the MDCK II MDR1 monolayers with a permeability of 5.7 × 10−5 cm sec−1 compared to an apical to basolateral permeability of 1.3 × 10−5 cm sec-1. The efflux could be inhibited with the P-gp inhibitor zosuquidar. Zosuquidar (0.4 μmol/L) reduced the efflux ratio (PB-A/PA-B) for verapamil 4.6–1.6. The presence of telmisartan, however, only caused a slight reduction in P-gp-mediated verapamil transport to an efflux ratio of 3.4. Overall, the results of the present in vitro approach indicate, that clinical use of telmisartan as a P-gp inhibitor may not be an effective strategy for increasing brain uptake of verapamil by co-administration with telmisartan. PMID:26171231

  16. Knockdown of HOXA10 reverses the multidrug resistance of human chronic mylogenous leukemia K562/ADM cells by downregulating P-gp and MRP-1.

    PubMed

    Yi, Ying-Jie; Jia, Xiu-Hong; Wang, Jian-Yong; Li, You-Jie; Wang, Hong; Xie, Shu-Yang

    2016-05-01

    Multidrug resistance (MDR) of leukemia cells is a major obstacle in chemotherapeutic treatment. The high expression and constitutive activation of P-glycoprotein (P-gp) and multidrug resistance protein-1 (MRP-1) have been reported to play a vital role in enhancing cell resistance to anticancer drugs in many tumors. The present study aimed to investigate the reversal of MDR by silencing homeobox A10 (HOXA10) in adriamycin (ADR)-resistant human chronic myelogenous leukemia (CML) K562/ADM cells by modulating the expression of P-gp and MRP-1. K562/ADM cells were stably transfected with HOXA10-targeted short hairpin RNA (shRNA). The results of reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot analysis showed that the mRNA and protein expression of HOXA10 was markedly suppressed following transfection with a shRNA-containing vector. The sensitivity of the K562/ADM cells to ADR was enhanced by the silencing of HOXA10, due to the increased intracellular accumulation of ADR. The accumulation of ADR induced by the silencing of HOXA10 may be due to the downregulation of P-gp and MRP-1. Western blot analysis revealed that downregulating HOXA10 inhibited the protein expression of P-gp and MRP-1. Taken together, these results suggest that knockdown of HOXA10 combats resistance and that HOXA10 is a potential target for resistant human CML. PMID:27035504

  17. Esters of the Marine-Derived Triterpene Sipholenol A Reverse P-GP-Mediated Drug Resistance

    PubMed Central

    Zhang, Yongchao; Zhang, Yun-Kai; Wang, Yi-Jun; Vispute, Saurabh G.; Jain, Sandeep; Chen, Yangmin; Li, Jessalyn; Youssef, Diaa T. A.; El Sayed, Khalid A.; Chen, Zhe-Sheng

    2015-01-01

    Our previous studies showed that several sipholane triterpenes, sipholenol A, sipholenone E, sipholenol L and siphonellinol D, have potent reversal effect for multidrug resistance (MDR) in cancer cells that overexpressed P-glycoprotein (P-gp/ABCB1). Through comparison of cytotoxicity towards sensitive and multi-drug resistant cell lines, we identified that the semisynthetic esters sipholenol A-4-O-acetate and sipholenol A-4-O-isonicotinate potently reversed P-gp-mediated MDR but had no effect on MRP1/ABCC1 and BCRP/ABCG2-mediated MDR. The results from [3H]-paclitaxel accumulation and efflux studies suggested that these two triterpenoids were able to increase the intracellular accumulation of paclitaxel by inhibiting its active efflux. In addition, western blot analysis revealed that these two compounds did not alter the expression levels of P-gp when treated up to 72 h. These sipholenol derivatives also stimulated the ATPase activity of P-gp membranes, which suggested that they might be substrates of P-gp. Moreover, in silico molecular docking studies revealed the virtual binding modes of these two compounds into human homology model of P-gp. In conclusion, sipholenol A-4-O-acetate and sipholenol A-4-O-isonicotinate efficiently inhibit the P-gp and may represent potential reversal agents for the treatment of multidrug resistant cancers. PMID:25874923

  18. Multifunctional PLGA Nanobubbles as Theranostic Agents: Combining Doxorubicin and P-gp siRNA Co-Delivery Into Human Breast Cancer Cells and Ultrasound Cellular Imaging.

    PubMed

    Yang, Hong; Deng, Liwei; Li, Tingting; Shen, Xue; Yan, Jie; Zuo, Liangming; Wu, Chunhui; Liu, Yiyao

    2015-12-01

    Multidrug resistance (MDR) is a major impediment to the success of cancer chemotherapy. One of the effective approaches to overcome MDR is to use nanoparticle-mediated the gene silence of chemotherapeutic export proteins by RNA interference to increase drug accumulation in drug resistant cancer cells. In this work, a new co-delivery system, DOX-PLGA/PEI/P-gp shRNA nanobubbles (NBs) around 327 nm, to overcome doxorubicin (DOX) resistance in MCF-7 human breast cancer was designed and developed. Positively charged polyethylenimine (PEI) were modified onto the surface of DOX-PLGA NBs through DCC/NHS crosslinking, and could efficiently condense P-gp shRNA into DOX-PLGA/PEI NBs at vector/shRNA weight ratios of 70:1 and above. An in vitro release profile demonstrated an efficient DOX release (more than 80%) from DOX-PLGA/PEI NBs at pH 4.4, suggesting a pH-responsive drug release for the multifunctionalized NBs. Cellular experimental results further showed that DOX-PLGA/PEI/P-gp shRNA NBs could facilitate cellular uptake of DOX into cells and increase the cell proliferation suppression effect of DOX against MCF-7/ADR cells (a DOX-resistant and P-glycoprotein (P-gp) over-expression cancer cell line). The IC50 of DOX-PLGA NBs against MCF-7/ADR cells was 2-fold lower than that of free DOX. The increased cellular uptake and nuclear accumulation of DOX delivered by DOX-PLGA/PEI/P-gp shRNA NBs in MCF-7/ADR cells was confirmed by fluorescence microscopy and fluorescence spectrophotometry, and might be owning to the down-regulation of P-gp and reduced the efflux of DOX. The cellular uptake mechanism of DOX-PLGA/PEI/P-gp shRNA NBs indicated that the macropinocytosis was one of the pathways for the uptake of NBs by MCF-7/ADR cells, which was also an energy-dependent process. Furthermore, the in vitro cellular ultrasound imaging suggested that the employment of the DOX-PLGA/PEI/P-gp shRNA NBs could efficiently enhance ultrasound imaging of cancer cells. These results demonstrated

  19. The expression of P-glycoprotein in leukemia cells is associated with the upregulated expression of nestin, a class 6 filament protein.

    PubMed

    Coculova, Martina; Imrichova, Denisa; Seres, M; Messingerova, Lucia; Bohacova, Viera; Sulova, Zdena; Breier, Albert

    2016-09-01

    Multidrug resistance (MDR) is a serious obstacle to the effective chemotherapeutic treatment of leukemia. Expression of plasma membrane P-glycoprotein (P-gp), a transporter involved in drug efflux, is the most frequently observed molecular causality of MDR. We observed the coexpression of P-gp and the filament protein nestin in the acute myeloid leukemia (AML) cell lines SKM-1 and MOLM-13 following the induction of P-gp expression using vincristine. Nestin is considered a marker of neural stem cells and neural progenitor cells. The aim of this study was to determine whether there is causal relationship between the expression of P-glycoprotein and the expression of nestin in both of these AML cell lines. The expression of P-gp was induced in SKM-1 cells by selective pressure using vincristine (VCR), mitoxantrone (MTX), azacytidine (AzaC) and lenalidomide (LEN). Whereas the selective pressure of VCR, MTX and AzaC also induced P-gp expression in MOLM-13 cells, LEN was found to be ineffective in this regard. In all cases in which P-gp expression was induced in SKM-1 and MOLM-13 cells, its expression was associated with the induction of nestin mRNA expression and the presence of a 200-220kDa nestin-immunoreactive protein band in western blots. Silencing P-gp expression using s10418 siRNA (known as the P-gp silencer) was associated with the downregulation of the nestin transcript level, demonstrated using RT-PCR. Nestin mRNA was also observed in two P-gp-positive variants of L1210 cells that were obtained either by selection with VCR or by transfection with a retrovirus encoding human P-gp. Detectable levels of nestin transcripts were not observed in P-gp-negative parental L1210 cells. Taken together, these results indicated that the induction of P-gp expression is causally associated with the expression of nestin in leukemia cells. PMID:27479651

  20. BCRP and P-gp relay overexpression in triple negative basal-like breast cancer cell line: a prospective role in resistance to Olaparib

    PubMed Central

    Dufour, Robin; Daumar, Pierre; Mounetou, Emmanuelle; Aubel, Corinne; Kwiatkowski, Fabrice; Abrial, Catherine; Vatoux, Catherine; Penault-Llorca, Frédérique; Bamdad, Mahchid

    2015-01-01

    The triple negative basal-like (TNBL) breast carcinoma is an aggressive and unfavorable prognosis disease. Inhibitors of poly(ADP-ribose) polymerase such as Olaparib could represent a promising targeted therapy but their sensitivity against Multidrug Resistance proteins (MDR), which causes resistance, is not well defined. Thus, our work focused on the analysis of P-gp and BCRP coexpression in the SUM1315 TNBL human cell line, in correlation with Olaparib intracellular concentration. Western blot analyses showed a clear coexpression of P-gp and BCRP in SUM1315 cells. A low cytotoxic Olaparib treatment clearly led to an increased expression of both BCRP and P-gp in these cells. Indeed, after 1.5 h of treatment, BCRP expression was increased with a 1.8 fold increase rate. Then, P-gp took over from 3 h to 15 h with an average increase rate of 1.8 fold, and finally returned to control value at 24 h. HPLC-UV analyses showed that, in the same treatment conditions, the intracellular Olaparib concentration increased from 1 h to 3 h and remained relatively stable until 24 h. Results suggest that the resistance mechanism induced by Olaparib in TNBL SUM1315 cell line may be overpassed if a cytotoxic and stable intracellular level of the drug can be maintained. PMID:26234720

  1. A New Class of Safe, Potent, and Specific P-gp Modulator: Flavonoid Dimer FD18 Reverses P-gp-Mediated Multidrug Resistance in Human Breast Xenograft in Vivo.

    PubMed

    Yan, Clare S W; Wong, Iris L K; Chan, Kin-Fai; Kan, Jason W Y; Chong, Tsz Cheung; Law, Man Chun; Zhao, Yunzhe; Chan, Shun Wan; Chan, Tak Hang; Chow, Larry M C

    2015-10-01

    Flavonoid dimer FD18 is a new class of dimeric P-gp modulator that can reverse cancer drug resistance. FD18 is a potent (EC50 = 148 nM for paclitaxel), safe (selective index = 574), and selective P-glycoprotein (P-gp) modulator. FD18 can modulate multidrug resistance toward paclitaxel, vinblastine, vincristine, doxorubicin, daunorubicin, and mitoxantrone in human breast cancer LCC6MDR in vitro. FD18 (1 μM) can revert chemosensitivity of LCC6MDR back to parental LCC6 level. FD18 was 11- to 46-fold more potent than verapamil. FD18 (1 μM) can increase accumulation of doxorubicin by 2.7-fold, daunorubicin (2.1-fold), and rhodamine 123 (5.2-fold) in LCC6MDR. FD18 inhibited P-gp-mediated doxorubicin efflux and has no effect on influx. FD18 at 1 μM did not affect the protein expression level of P-gp. Pharmacokinetics studies indicated that intraperitoneal administration of 45 mg/kg FD18 was enough to maintain a plasma level above EC50 (148 nM) for more than 600 min. Toxicity studies with FD18 (90 mg/kg, i.p. for 12 times in 22 days) with paclitaxel (12 mg/kg, i.v. for 12 times in 22 days) revealed no obvious toxicity or death in mice. In vivo efficacy studies indicated that FD18 (45 mg/kg, i.p. for 12 times in 22 days) together with paclitaxel (12 mg/kg, i.v. for 12 times in 22 days) resulted in a 46% reduction in LCC6MDR xenograft volume (n = 11; 648 ± 84 mm(3)) compared to paclitaxel control (n = 8; 1201 ± 118 mm(3)). There were no animal deaths or significant drop in body weight and vital organ wet weight. FD18 can increase paclitaxel accumulation in LCC6MDR xenograft by 1.8- to 2.2-fold. The present study suggests that FD18 represents a new class of safe and potent P-gp modulator in vivo. PMID:26291333

  2. A Potent and Selective P-gp Modulator for Altering Multidrug Resistance Due to Pump Overexpression.

    PubMed

    Guglielmo, Stefano; Contino, Marialessandra; Lazzarato, Loretta; Perrone, Maria Grazia; Blangetti, Marco; Fruttero, Roberta; Colabufo, Nicola Antonio

    2016-02-17

    P-glycoprotein (P-gp) is a membrane protein responsible for the active transport of several endogenous and exogenous substances. It constitutes a defense mechanism and, at the same time, it severely compromises the success rate of antitumor chemotherapy. In this study a small library of alkyl/oxyalkyl derivatives of MC70 [4'-(6,7-dimethoxy-3,4-dihydro-1H-isoquinolin-2-ylmethyl)biphenyl-4-ol], a well-known P-gp inhibitor, was synthesized through straightforward functionalization of the phenolic group present in the structure of MC70. All compounds were characterized for their effect on P-gp, proving capable of blocking P-gp-mediated calcein-AM efflux with micromolar potency, following their ability to act as high-affinity substrates of this transporter. Excitingly, compound 4 [6,7-dimethoxy-2-((4'-butoxybiphen-4-yl)methyl)-1,2,3,4-tetrahydroisoquinoline] exhibited low nanomolar potency (5.2 nm) and had a peculiar activity profile, acting both as a positive allosteric modulator and as a substrate of the transporter. A new and more efficient synthesis of MC70 is also described. PMID:26797828

  3. Avermectin induces P-glycoprotein expression in S2 cells via the calcium/calmodulin/NF-κB pathway.

    PubMed

    Luo, Liang; Sun, Yin-Jian; Yang, Lin; Huang, Shile; Wu, Yi-Jun

    2013-04-25

    Avermectin (AVM) is a macrocyclic lactone agent widely used as a nematicide, acaricide and insecticide in veterinary medicine and plant protection. P-glycoprotein (P-gp) is an ATP-dependent drug efflux pump for xenobiotic compounds, and is involved in multidrug resistance. To understand the development of AVM resistance in invertebrates, we investigated the mechanisms by which AVM affected P-gp expression in Drosophila S2 cells. We found that AVM induced upregulation of P-gp protein expression, increased P-gp ATPase activity and enhanced cellular efflux of the P-gp substrate rhodamine 123 from cells. Furthermore, we observed that AVM-induced expression of P-gp was due to elevation of intracellular calcium concentration ([Ca(2+)](i)). This occurred both directly, by activating calcium ion channels, and indirectly, by activating chloride ion channels. These results are supported by our observations that verapamil, a Ca(2+) channel blocker, and niflumic acid, a chloride channel antagonist, significantly attenuated AVM-induced [Ca(2+)](i) elevation, thereby reducing P-gp expression. Inhibition of P-gp with anti-P-gp antibody or cyclosporine A (a P-gp inhibitor) reduced the AVM-induced elevation of [Ca(2+)](i), implying that P-gp and [Ca(2+)](i) regulate each other. Finally, we found that trifluoperazine, a calmodulin inhibitor, and pyrrolidine dithiocarbamic acid, an NF-κB inhibitor, attenuated the AVM-induced expression of P-gp, suggesting that AVM induces P-gp protein expression via the calmodulin/Relish (NF-κB) signaling pathway. PMID:23523950

  4. Differential effect of P-gp and MRP2 on cellular translocation of gemifloxacin

    PubMed Central

    Vadlapatla, Ramya Krishna; Vadlapudi, Aswani Dutt; Kwatra, Deep; Pal, Dhananjay; Mitra, Ashim K.

    2011-01-01

    Fluoroquinolones are broad spectrum antibiotics widely indicated in the treatment of both human and animal diseases. The primary objective of this study was to assess short and long term affinity of gemifloxacin towards efflux transporters (P-gp, MRP2) and nuclear hormone receptor (PXR). Uptake and dose dependent inhibition studies were performed with [14C] erythromycin (0.25μCi/ml) on MDCKII-MDR1 and MDCKII-MRP2 cells. Cellular accumulation of calcein-AM was further determined to confirm the affinity of gemifloxacin towards P-gp and MRP2. Transport studies were conducted to determine bi-directional permeability and to assess efflux ratio of gemifloxacin. LS-180 cells were treated with three different concentrations of gemifloxacin for 72hrs and real-time PCR analysis was performed to study the quantitative gene expression levels of PXR, MDR1 and MRP2. Further, [14C] erythromycin uptake was also performed on LS-180 treated cells to better delineate the functional activity of efflux transporters. Results from our study suggest that gemifloxacin may be a substrate of both the efflux transporters studied. This compound inhibited both P-gp and MRP2 mediated efflux of [14C] erythromycin in a dose dependent manner with IC50 values of 123 ± 2μM and 16 ± 2μM, respectively. The efflux ratio of [14C] erythromycin lowered from 3.56 to 1.63 on MDCKII-MDR1 cells and 4.93 to 1.26 on MDCKII-MRP2 cells. This significant reduction in efflux ratio further confirmed the substrate specificity of gemifloxacin towards P-gp and MRP2. Long term exposure significantly induced the expression of PXR (18 fold), MDR1 (6 fold) and MRP2 (6 fold). A decrease (20%) in [14C] erythromycin uptake further confirmed the elevated functional activity of P-gp and MRP2. In conclusion, our studies demonstrated that gemifloxacin is effluxed by both P-gp and MRP2. Long term exposure induced their gene expression and functional activity. This substrate specificity of gemifloxacin towards these efflux

  5. Oligoribonuclease is the primary degradative enzyme for pGpG in Pseudomonas aeruginosa that is required for cyclic-di-GMP turnover

    PubMed Central

    Orr, Mona W.; Donaldson, Gregory P.; Severin, Geoffrey B.; Wang, Jingxin; Sintim, Herman O.; Waters, Christopher M.; Lee, Vincent T.

    2015-01-01

    The bacterial second messenger cyclic di-GMP (c-di-GMP) controls biofilm formation and other phenotypes relevant to pathogenesis. Cyclic-di-GMP is synthesized by diguanylate cyclases (DGCs). Phosphodiesterases (PDE-As) end signaling by linearizing c-di-GMP to 5ʹ-phosphoguanylyl-(3ʹ,5ʹ)-guanosine (pGpG), which is then hydrolyzed to two GMP molecules by yet unidentified enzymes termed PDE-Bs. We show that pGpG inhibits a PDE-A from Pseudomonas aeruginosa. In a dual DGC and PDE-A reaction, excess pGpG extends the half-life of c-di-GMP, indicating that removal of pGpG is critical for c-di-GMP homeostasis. Thus, we sought to identify the PDE-B enzyme(s) responsible for pGpG degradation. A differential radial capillary action of ligand assay-based screen for pGpG binding proteins identified oligoribonuclease (Orn), an exoribonuclease that hydrolyzes two- to five-nucleotide-long RNAs. Purified Orn rapidly converts pGpG into GMP. To determine whether Orn is the primary enzyme responsible for degrading pGpG, we assayed cell lysates of WT and ∆orn strains of P. aeruginosa PA14 for pGpG stability. The lysates from ∆orn showed 25-fold decrease in pGpG hydrolysis. Complementation with WT, but not active site mutants, restored hydrolysis. Accumulation of pGpG in the ∆orn strain could inhibit PDE-As, increasing c-di-GMP concentration. In support, we observed increased transcription from the c-di-GMP–regulated pel promoter. Additionally, the c-di-GMP–governed auto-aggregation and biofilm phenotypes were elevated in the ∆orn strain in a pel-dependent manner. Finally, we directly detect elevated pGpG and c-di-GMP in the ∆orn strain. Thus, we identified that Orn serves as the primary PDE-B enzyme that removes pGpG, which is necessary to complete the final step in the c-di-GMP degradation pathway. PMID:26305945

  6. Oligoribonuclease is the primary degradative enzyme for pGpG in Pseudomonas aeruginosa that is required for cyclic-di-GMP turnover.

    PubMed

    Orr, Mona W; Donaldson, Gregory P; Severin, Geoffrey B; Wang, Jingxin; Sintim, Herman O; Waters, Christopher M; Lee, Vincent T

    2015-09-01

    The bacterial second messenger cyclic di-GMP (c-di-GMP) controls biofilm formation and other phenotypes relevant to pathogenesis. Cyclic-di-GMP is synthesized by diguanylate cyclases (DGCs). Phosphodiesterases (PDE-As) end signaling by linearizing c-di-GMP to 5'-phosphoguanylyl-(3',5')-guanosine (pGpG), which is then hydrolyzed to two GMP molecules by yet unidentified enzymes termed PDE-Bs. We show that pGpG inhibits a PDE-A from Pseudomonas aeruginosa. In a dual DGC and PDE-A reaction, excess pGpG extends the half-life of c-di-GMP, indicating that removal of pGpG is critical for c-di-GMP homeostasis. Thus, we sought to identify the PDE-B enzyme(s) responsible for pGpG degradation. A differential radial capillary action of ligand assay-based screen for pGpG binding proteins identified oligoribonuclease (Orn), an exoribonuclease that hydrolyzes two- to five-nucleotide-long RNAs. Purified Orn rapidly converts pGpG into GMP. To determine whether Orn is the primary enzyme responsible for degrading pGpG, we assayed cell lysates of WT and ∆orn strains of P. aeruginosa PA14 for pGpG stability. The lysates from ∆orn showed 25-fold decrease in pGpG hydrolysis. Complementation with WT, but not active site mutants, restored hydrolysis. Accumulation of pGpG in the ∆orn strain could inhibit PDE-As, increasing c-di-GMP concentration. In support, we observed increased transcription from the c-di-GMP-regulated pel promoter. Additionally, the c-di-GMP-governed auto-aggregation and biofilm phenotypes were elevated in the ∆orn strain in a pel-dependent manner. Finally, we directly detect elevated pGpG and c-di-GMP in the ∆orn strain. Thus, we identified that Orn serves as the primary PDE-B enzyme that removes pGpG, which is necessary to complete the final step in the c-di-GMP degradation pathway. PMID:26305945

  7. Cbl-b inhibits P-gp transporter function by preventing its translocation into caveolae in multiple drug-resistant gastric and breast cancers

    PubMed Central

    Zhang, Ye; Qu, Xiujuan; Teng, Yuee; Li, Zhi; Xu, Ling; Liu, Jing; Ma, Yanju; Fan, Yibo; Li, Ce; Liu, Shizhou; Wang, Zhenning; Hu, Xuejun; Zhang, Jingdong; Liu, Yunpeng

    2015-01-01

    The transport function of P-glycoprotein (P-gp) requires its efficient localization to caveolae, a subset of lipid rafts, and disruption of caveolae suppresses P-gp transport function. However, the regulatory molecules involved in the translocation of P-gp into caveolae remain unknown. In the present study, we showed that c-Src dependent Caveolin-1 phosphorylation promoted the translocation of P-gp into caveolae, resulting in multidrug resistance in adriamycin resistant gastric cancer SGC7901/Adr and breast cancer MCF-7/Adr cells. In a negative feedback loop, the translocation of Cbl-b from the nucleus to the cytoplasm prevented the localization of P-gp to caveolae resulting in the reversal of MDR through the ubiquitination and degradation of c-Src. Clinical data showed a significant positive relationship between Cbl-b expression and survival in P-gp positive breast cancer patients who received anthracycline-based chemotherapy. Our findings identified a new regulatory mechanism of P-gp transport function in multiple drug-resistant gastric and breast cancers. PMID:25788263

  8. Abamectin resistance in Drosophila is related to increased expression of P-glycoprotein via the dEGFR and dAkt pathways.

    PubMed

    Luo, Liang; Sun, Ying-Jian; Wu, Yi-Jun

    2013-08-01

    Many insects have evolved resistance to abamectin but the mechanisms involved in this resistance have not been well characterized. P-glycoprotein (P-gp), an ATP-dependent drug-efflux pump transmembrane protein, may be involved in abamectin resistance. We investigated the role of P-gp in abamectin (ABM) resistance in Drosophila using an ABM-resistant strain developed in the laboratory. A toxicity assay, Western blotting analysis and a vanadate-sensitive ATPase activity assay all demonstrated the existence of a direct relationship between P-gp expression and ABM resistance in these flies. Our observations indicate that P-gp levels in flies' heads were higher than in their thorax and abdomen, and that both P-gp levels and LC(50) values were higher in resistant than in susceptible and P-gp-deficient strains. In addition, P-gp levels in the blood-brain barrier (BBB) of resistant flies were higher than in susceptible and P-gp-deficient flies, which is further evidence that a high level of P-gp in the BBB is related to ABM resistance. Furthermore, we found greater expression of Drosophila EGFR (dEGFR) in the resistant strain than in the susceptible strain, and that the level of Drosophila Akt (dAkt) was much higher in resistant than in susceptible flies, whereas that in P-gp-deficient flies was very low. Compared to susceptible flies, P-gp levels in the resistant strain were markedly suppressed by the dEGFR and dAkt inhibitors lapatinib and wortmannin. These results suggest that the increased P-gp in resistant flies was regulated by the dEGFR and dAkt pathways and that increased expression of P-gp is an important component of ABM resistance in insects. PMID:23648830

  9. A plausible explanation for enhanced bioavailability of P-gp substrates in presence of piperine: simulation for next generation of P-gp inhibitors.

    PubMed

    Singh, Durg Vijay; Godbole, Madan M; Misra, Krishna

    2013-01-01

    P-glycoprotein (P-gp) has a major role to play in drug pharmacokinetics and pharmacodynamics, since it effluxes many cytotoxic hydrophobic anticancer drugs from gastrointestinal tract, brain, liver and kidney. Piperine is known to enhance the bioavailability of curcumin, as a substrate of P-gp by at least 2000%. Besides these at least 50 other substrates and inhibitors of P-gp have been reported so far. All P-gp inhibitors have diverse structures. Although little is known about binding of some flavonoids and steroids at the NBD (nucleotide binding domain) of P-gp in the vicinity of ATP binding site inhibiting its hydrolysis, a valid explanation of how P-gp accommodates such a diverse set of inhibitors is still awaited. In the present study, piperine up to 100 μM has not shown observable cytotoxic effect on MDCK cell line, and it has been shown to accumulate rhodamine by fluorescence microscopy and fluorescent activated cell sorter in MDCK cells. Computational simulation for piperine and some first and second generation P-gp inhibitors has shown that these dock at the NBD site of P-gp. A comparative simulation study has been carried out regarding their docking and binding energies. Binding conformation of P-gp co-crystallized complexes with ADP, AMP-PNP (Adenylyl-imidodiphosphate), and ATP were compared with piperine. The receptor based E-pharmacophore of docked piperine has been simulated to find common features amongst P-gp inhibitors. Finally it has been concluded that piperine could be utilized as base molecule for design and development of safe non-toxic inhibitor of P-gp in order to enhance the bioavailability of most of its substrates. PMID:22864626

  10. Expression and significance of glucose transporter-1, P-glycoprotein, multidrug resistance-associated protein and glutathione S-transferase-π in laryngeal carcinoma

    PubMed Central

    MAO, ZHONG-PING; ZHAO, LI-JUN; ZHOU, SHUI-HONG; LIU, MENG-QIN; TAN, WEI-FENG; YAO, HONG-TIAN

    2015-01-01

    Increasing glucose transporter-1 (GLUT-1) activity is one of the most important ways to increase the cellular influx of glucose. We previously demonstrated that increased GLUT-1 expression was an independent predictor of survival in patients with laryngeal carcinoma. Thus, GLUT-1 may present a novel therapeutic target in laryngeal carcinoma. In this study, the expression of GLUT-1, P-glycoprotein (P-gp), multidrug resistance-associated protein 1 (MRP1) and glutathione S-transferase-π (GST-π) in laryngeal carcinomas was investigated by immunohistochemistry. Additionally, possible correlations between GLUT-1 and P-gp, MRP1 and GST-π and various clinicopathological parameters were analyzed. In this study, 52.9% (18/34), 58.8% (20/34), 20.6% (7/34) and 58.8% (20/34) of the laryngeal carcinomas were positive for GLUT-1, P-gp, MRP1 and GST-π, respectively. The expression of GLUT-1, P-gp, MRP1 and GST-π was higher in laryngeal carcinoma specimens when compared with laryngeal precancerous lesions (P<0.05). Pearson’s correlation analysis showed correlations between GLUT-1 and P-gp (r=0.364; P=0.034), GLUT-1 and MRP1 (r=0.359; P=0.037) and P-gp and GST-π (r=0.426; P=0.012). GLUT-1 expression was found to significantly correlate with tumor-node-metastasis classification (P=0.02) and clinical stage (P=0.037). Furthermore, P-gp was found to significantly correlate with clinical stage (P=0.026). Univariate analysis showed that MRP1 expression was significantly associated with poor survival (c2=5.16; P=0.023). Multivariate analysis revealed that lymph node metastasis (P=0.009) and MRP1 overexpression (P=0.023) were significant predictors of poor survival. In the present study, the expression of GLUT-1, P-gp, MRP1 and GST-π in laryngeal carcinomas was investigated, as well as the correlations between these proteins. P-gp was found to significantly correlate with clinical stage, while MRP1 overexpression was significantly associated with poor survival. PMID:25621055

  11. MDR1 synonymous polymorphisms alter transporter specificity and protein stability in a stable epithelial monolayer.

    PubMed

    Fung, King Leung; Pan, James; Ohnuma, Shinobu; Lund, Paul E; Pixley, Jessica N; Kimchi-Sarfaty, Chava; Ambudkar, Suresh V; Gottesman, Michael M

    2014-01-15

    The drug efflux function of P-glycoprotein (P-gp) encoded by MDR1 can be influenced by genetic polymorphisms, including two synonymous changes in the coding region of MDR1. Here we report that the conformation of P-gp and its drug efflux activity can be altered by synonymous polymorphisms in stable epithelial monolayers expressing P-gp. Several cell lines with similar MDR1 DNA copy number were developed and termed LLC-MDR1-WT (expresses wild-type P-gp), LLC-MDR1-3H (expresses common haplotype P-gp), and LLC-MDR1-3HA (a mutant that carries a different valine codon in position 3435). These cell lines express similar levels of recombinant mRNA and protein. P-gp in each case is localized on the apical surface of polarized cells. However, the haplotype and its mutant P-gps fold differently from the wild-type, as determined by UIC2 antibody shift assays and limited proteolysis assays. Surface biotinylation experiments suggest that the non-wild-type P-gps have longer recycling times. Drug transport assays show that wild-type and haplotype P-gp respond differently to P-gp inhibitors that block efflux of rhodamine 123 or mitoxantrone. In addition, cytotoxicity assays show that the LLC-MDR1-3H cells are more resistant to mitoxantrone than the LLC-MDR1-WT cells after being treated with a P-gp inhibitor. Expression of polymorphic P-gp, however, does not affect the host cell's morphology, growth rate, or monolayer formation. Also, ATPase activity assays indicate that neither basal nor drug-stimulated ATPase activities are affected in the variant P-gps. Taken together, our findings indicate that "silent" polymorphisms significantly change P-gp function, which would be expected to affect interindividual drug disposition and response. PMID:24305879

  12. The influence of passage number for Caco2 cell models when evaluating P-gp mediated drug transport.

    PubMed

    Senarathna, S M D K Ganga; Crowe, A

    2015-12-01

    Caco2 cells are a human adenocarcinoma cell line that forms tight junctions and are widely used to examine bidirectional drug transport as well as P-glycoprotein mediated efflux. Unfortunately Caco2 cell lines can be very heterogeneous in nature. Our aim was to improve the Caco2 cell model for determination of P-glycoprotein mediated drug transport. Young passage Caco2 from ATCC had inadequate expression of P-glycoprotein, therefore three approaches were adopted to upregulate Caco2 P-glycoprotein expression to mimic that in vivo; a) incubation of mature Caco2 monolayer with rifampicin, b) prolonged exposure of Caco2 cells to vinblastine (generating the Caco2 VIN line), and c) splitting cells every 7 to 9 days until late passage numbers (over P80) were available. Upon development of the models, P-gp expression and activity was determined using western blotting and bidirectional transport studies of rhodamine123. All four models exhibited P-gp mediated efflux transport for rhodamine123. Incubation with rifampicin did not alter bidirectional transport compared to passage 44 cells. Increased passage number altered P-glycoprotein expression and the efflux ratio increased to 4.7 for passage 80 from 1.4 of passage 44. The highest basolateral to apical transport was observed for both passage 89 Caco2 and the Caco2 VIN model with an efflux ratio of 13 to 14. Western blot images confirmed the increased P-glycoprotein expression of late passage and Caco2 VIN. Caco2 cells are not ready for P-gp related research when first acquired from ATCC (Passage 18). Late passage Caco2 cell monolayers or Caco2 VIN models are needed to determine P-gp mediated efflux transport. PMID:26817277

  13. Asclepiasterol, a novel C21 steroidal glycoside derived from Asclepias curassavica, reverses tumor multidrug resistance by down-regulating P-glycoprotein expression.

    PubMed

    Yuan, Wei-Qi; Zhang, Rong-Rong; Wang, Jun; Ma, Yan; Li, Wen-Xue; Jiang, Ren-Wang; Cai, Shao-Hui

    2016-05-24

    Multidrug resistance (MDR) mediated by P-glycoprotein (P-gp) is a major cause of cancer therapy failure. In this study, we identified a novel C21 steroidal glycoside, asclepiasterol, capable of reversing P-gp-mediated MDR. Asclepiasterol (2.5 and 5.0μM) enhanced the cytotoxity of P-gp substrate anticancer drugs in MCF-7/ADR and HepG-2/ADM cells. MDR cells were more responsive to paclitaxel in the presence of asclepiasterol, and colony formation of MDR cells was only reduced upon treatment with a combination of asclepiasterol and doxorubicin. Consistent with these findings, asclepiasterol treatment increased the intracellular accumulation of doxorubicin and rhodamine 123 (Rh123) in MDR cells. Asclepiasterol decreased expression of P-gp protein without stimulating or suppressing MDR1 mRNA levels. Asclepiasterol-mediated P-gp suppression caused inhibition of ERK1/2 phosphorylation in two MDR cell types, and EGF, an activator of the MAPK/ERK pathway, reversed the P-gp down-regulation, implicating the MAPK/ERK pathway in asclepiasterol-mediated P-gp down-regulation. These results suggest that asclepiasterol could be developed as a modulator for reversing P-gp-mediated MDR in P-gp-overexpressing cancer variants. PMID:27129170

  14. Induction of P-glycoprotein expression and activity by Aconitum alkaloids: Implication for clinical drug-drug interactions.

    PubMed

    Wu, Jinjun; Lin, Na; Li, Fangyuan; Zhang, Guiyu; He, Shugui; Zhu, Yuanfeng; Ou, Rilan; Li, Na; Liu, Shuqiang; Feng, Lizhi; Liu, Liang; Liu, Zhongqiu; Lu, Linlin

    2016-01-01

    The Aconitum species, which mainly contain bioactive Aconitum alkaloids, are frequently administered concomitantly with other herbal medicines or chemical drugs in clinics. The potential risk of drug-drug interactions (DDIs) arising from co-administration of Aconitum alkaloids and other drugs against specific targets such as P-glycoprotein (P-gp) must be evaluated. This study focused on the effects of three representative Aconitum alkaloids: aconitine (AC), benzoylaconine (BAC), and aconine, on the expression and activity of P-gp. We observed that Aconitum alkaloids increased P-gp expression in LS174T and Caco-2 cells in the order AC > BAC > aconine. Nuclear receptors were involved in the induction of P-gp. AC and BAC increased the P-gp transport activity. Strikingly, intracellular ATP levels and mitochondrial mass also increased. Furthermore, exposure to AC decreased the toxicity of vincristine and doxorubicin towards the cells. In vivo, AC significantly up-regulated the P-gp protein levels in the jejunum, ileum, and colon of FVB mice, and protected them against acute AC toxicity. Taken together, the findings of our in vitro and in vivo experiments indicate that AC can induce P-gp expression, and that co-administration of AC with P-gp substrate drugs may cause DDIs. Our findings have important implications for Aconitum therapy in clinics. PMID:27139035

  15. Induction of P-glycoprotein expression and activity by Aconitum alkaloids: Implication for clinical drug–drug interactions

    PubMed Central

    Wu, Jinjun; Lin, Na; Li, Fangyuan; Zhang, Guiyu; He, Shugui; Zhu, Yuanfeng; Ou, Rilan; Li, Na; Liu, Shuqiang; Feng, Lizhi; Liu, Liang; Liu, Zhongqiu; Lu, Linlin

    2016-01-01

    The Aconitum species, which mainly contain bioactive Aconitum alkaloids, are frequently administered concomitantly with other herbal medicines or chemical drugs in clinics. The potential risk of drug–drug interactions (DDIs) arising from co-administration of Aconitum alkaloids and other drugs against specific targets such as P-glycoprotein (P-gp) must be evaluated. This study focused on the effects of three representative Aconitum alkaloids: aconitine (AC), benzoylaconine (BAC), and aconine, on the expression and activity of P-gp. We observed that Aconitum alkaloids increased P-gp expression in LS174T and Caco-2 cells in the order AC > BAC > aconine. Nuclear receptors were involved in the induction of P-gp. AC and BAC increased the P-gp transport activity. Strikingly, intracellular ATP levels and mitochondrial mass also increased. Furthermore, exposure to AC decreased the toxicity of vincristine and doxorubicin towards the cells. In vivo, AC significantly up-regulated the P-gp protein levels in the jejunum, ileum, and colon of FVB mice, and protected them against acute AC toxicity. Taken together, the findings of our in vitro and in vivo experiments indicate that AC can induce P-gp expression, and that co-administration of AC with P-gp substrate drugs may cause DDIs. Our findings have important implications for Aconitum therapy in clinics. PMID:27139035

  16. Time and concentration dependency of P-gp, MRP1 and MRP5 induction in response to gemcitabine uptake in Capan-2 pancreatic cancer cells.

    PubMed

    Kohan, Hamed Gilzad; Boroujerdi, Mehdi

    2015-01-01

    1. Influx and efflux proteins play a major role in the overall uptake and efficacy of chemotherapeutic agents and cellular chemo-resistance. 2. The present study investigated the time course and dose dependency of the induction of three efflux proteins, P-gp, MRP1 and MRP5, in response to gemcitabine exposure in Capan-2 pancreatic cancer cell line at transcriptional and translational levels. The influence of exposure on the influx protein (ENT1), the net cellular uptake of the gemcitabine, the overall ATPase activity and the cell death rate were also measured. 3. The time course of the expression exhibited an initial rise, toward a plateau level. The estimated Km and Vmax confirmed that MRP5 and to a lesser extent MRP1 are the prominent proteins for efflux of gemcitabine. Both mRNA and protein expression demonstrated the time and concentration dependency of the induction; and the elevated ATPase activity validated that the induced efflux proteins are functionally active. 4. The results of the study revealed that the efficacy window of gemcitabine as it relates to the function of the efflux proteins is concentration and temporal dependent and is well correlated to the first 60 min of exposure. PMID:25564970

  17. Accurate models for P-gp drug recognition induced from a cancer cell line cytotoxicity screen.

    PubMed

    Levatić, Jurica; Ćurak, Jasna; Kralj, Marijeta; Šmuc, Tomislav; Osmak, Maja; Supek, Fran

    2013-07-25

    P-glycoprotein (P-gp, MDR1) is a promiscuous drug efflux pump of substantial pharmacological importance. Taking advantage of large-scale cytotoxicity screening data involving 60 cancer cell lines, we correlated the differential biological activities of ∼13,000 compounds against cellular P-gp levels. We created a large set of 934 high-confidence P-gp substrates or nonsubstrates by enforcing agreement with an orthogonal criterion involving P-gp overexpressing ADR-RES cells. A support vector machine (SVM) was 86.7% accurate in discriminating P-gp substrates on independent test data, exceeding previous models. Two molecular features had an overarching influence: nearly all P-gp substrates were large (>35 atoms including H) and dense (specific volume of <7.3 Å(3)/atom) molecules. Seven other descriptors and 24 molecular fragments ("effluxophores") were found enriched in the (non)substrates and incorporated into interpretable rule-based models. Biological experiments on an independent P-gp overexpressing cell line, the vincristine-resistant VK2, allowed us to reclassify six compounds previously annotated as substrates, validating our method's predictive ability. Models are freely available at http://pgp.biozyne.com . PMID:23772653

  18. Inhibitory effects of herbal constituents on P-glycoprotein in vitro and in vivo: Herb–drug interactions mediated via P-gp

    SciTech Connect

    Li, Xue Hu, Jinping Wang, Baolian Sheng, Li Liu, Zhihao Yang, Shuang Li, Yan

    2014-03-01

    Modulation of drug transporters via herbal medicines which have been widely used in combination with conventional prescription drugs may result in herb–drug interactions in clinical practice. The present study was designed to investigate the inhibitory effects of 50 major herbal constituents on P-glycoprotein (P-gp) in vitro and in vivo as well as related inhibitory mechanisms. Among these herbal medicines, four constituents, including emodin, 18β-glycyrrhetic acid (18β-GA), dehydroandrographolide (DAG), and 20(S)-ginsenoside F{sub 1} [20(S)-GF{sub 1}] exhibited significant inhibition (> 50%) on P-gp in MDR1-MDCKII and Caco-2 cells. Emodin was the strongest inhibitor of P-gp (IC{sub 50} = 9.42 μM), followed by 18β-GA (IC{sub 50} = 21.78 μM), 20(S)-GF{sub 1} (IC{sub 50} = 76.08 μM) and DAG (IC{sub 50} = 77.80 μM). P-gp ATPase activity, which was used to evaluate the affinity of substrates to P-gp, was stimulated by emodin and DAG with K{sub m} and V{sub max} values of 48.61, 29.09 μM and 71.29, 38.45 nmol/min/mg protein, respectively. However, 18β-GA and 20(S)-GF{sub 1} exhibited significant inhibition on both basal and verapamil-stimulated P-gp ATPase activities at high concentration. Molecular docking analysis (CDOCKER) further elucidated the mechanism for structure–inhibition relationships of herbal constituents with P-gp. When digoxin was co-administered to male SD rats with emodin or 18β-GA, the AUC{sub 0−t} and Cmax of digoxin were increased by approximately 51% and 58%, respectively. Furthermore, 18β-GA, DAG, 20(S)-GF{sub 1} and Rh{sub 1} at 10 μM significantly inhibited CYP3A4/5 activity, while emodin activated the metabolism of midazolam in human liver microsomes. In conclusion, four herbal constituents demonstrated inhibition of P-gp to specific extents in vitro and in vivo. Taken together, our findings provided the basis for the reliable assessment of the potential risks of herb–drug interactions in humans. - Highlights: • Emodin, 18

  19. Contribution of radixin to P-glycoprotein expression and transport activity in mouse small intestine in vivo.

    PubMed

    Yano, Kentaro; Tomono, Takumi; Sakai, Riyo; Kano, Takashi; Morimoto, Kaori; Kato, Yukio; Ogihara, Takuo

    2013-08-01

    The ERM proteins, ezrin, radixin, and moesin, are membrane-cytoskeleton cross-linkers with multiple physiological functions. We previously showed that radixin is involved in posttranslational regulation of P-glycoprotein (P-gp) in human hepatoblastoma HepG2 cells. Here, we investigated the physiological role of radixin in regulating P-gp expression and activity in the small intestine by comparing wild-type- and radixin knockout (Rdx) mice. In intestinal tissue homogenates, P-gp protein levels increased markedly from the upper part to the lower part of the small intestine in both wild-type- and Rdx(-/-) mice. In the membrane fractions, a similar pattern was seen in wild-type mice. However, the membrane expression of P-gp protein remained at the same level from the upper to the lower part of the small intestine in Rdx(-/-) mice. When rhodamine123 (Rho123), a substrate of P-gp, was orally administered to Rdx(-/-) and wild-type mice, the absorption phase of Rho123 was greater in Rdx(-/-) than in wild-type mice, whereas the elimination phase in Rdx(-/-) mice was not different from that of wild-type mice. Our results indicate that radixin plays an important role in regulating P-gp localization and P-gp functional activity at the intestinal membrane. PMID:23754525

  20. P-glycoprotein expression in Perna viridis after exposure to Prorocentrum lima, a dinoflagellate producing DSP toxins.

    PubMed

    Huang, Lu; Wang, Jie; Chen, Wen-Chang; Li, Hong-Ye; Liu, Jie-Sheng; Tao Jiang; Yang, Wei-Dong

    2014-08-01

    Bivalves naturally exposed to toxic algae have mechanisms to prevent from harmful effects of diarrhetic shellfish poisoning (DSP) toxins. However, quite few studies have examined the mechanisms associated, and the information currently available is still insufficient. Multixenobiotic resistance (MXR) is ubiquitous in aquatic invertebrates and plays an important role in defense against xenobiotics. Here, to explore the roles of P-glycoprotein (P-gp) in the DSP toxins resistance in shellfish, complete cDNA of P-gp gene in the mussel Perna viridis was cloned and analyzed. The accumulation of okadaic acid (OA), a main component of DSP toxins, MXR activity and expression of P-gp in gills of P. viridis were detected after exposure to Prorocentrum lima, a dinoflagellate producing DSP toxins in the presence or absence of P-gp inhibitors PGP-4008, verapamil (VER) and cyclosporin A (CsA). The mussel P. viridis P-gp closely matches MDR/P-gp/ABCB protein from various organisms, having a typical sequence organization as full transporters from the ABCB family. After exposure to P. lima, OA accumulation, MXR activity and P-gp expression significantly increased in gills of P. viridis. The addition of P-gp-specific inhibitors PGP-4008 and VER decreased MXR activity induced by P. lima, but had no effect on the OA accumulation in gills of P. viridis. However, CsA, a broad-spectrum inhibitor of ABC transporter not only decreased MXR activity, but also increased OA accumulation in gills of P. viridis. Together with the ubiquitous presence of other ABC transporters such as MRP/ABCC in bivalves and potential compensatory mechanism in P-gp and MRP-mediated resistance, we speculated that besides P-gp, other ABC transporters, especially MRP might be involved in the resistance mechanisms to DSP toxins. PMID:24811006

  1. Expression of multidrug resistance proteins in invasive ductal carcinoma of the breast.

    PubMed

    Li, Weiquan; Song, Maomin

    2014-11-01

    Chemotherapy is commonly used for the treatment of breast cancer. However, the resistance to chemotherapeutic agents, often mediated by multidrug resistance (MDR) mechanisms, is a common occurrence. The present study examined the expression of several MDR-related proteins (MRPs) in invasive ductal carcinoma (IDC) of the breast, and assessed their association with clinicopathological variables and their prognostic significance. In addition, immunohistochemistry was used to measure the expression of MRP, p-glycoprotein (P-gp), topoisomerase 2α (Topo2α), thymidylate synthase (TS) and glutathione-S-transferase π (GST-π) in 156 resected IDCs of the breast. Pearson's χ(2) test and Spearman's correlation coefficient were used to analyze the association between MDR protein expression and several clinicopathological variables. The association between each of the five MDR proteins was also examined. Furthermore, Kaplan-Meier analysis and Cox regression modeling were used to assess overall survival. The expression of MRP, P-gp, Topo2α, TS and GST-π was detected in 20.5% (32/156), 25.0% (39/156), 84.0% (131/156), 41.7% (65/156) and 41.0% (64/156) of cases examined, respectively. No correlation was identified between MRP and Topo-2α and the clinicopathological variables examined. By contrast, P-gp (χ(2)=20.226; P<0.0001) and GST-π (χ(2)=35.032; P<0.0001) were found to positively correlate with tumor grade. In addition, staining for TS was associated with axillary lymph node metastasis (χ(2)=42.281; P<0.0001). The expression levels of P-gp and GST-π were found to be significantly correlated (r= 0.319; P<0.0001). Furthermore, GST-π expression was elevated in estrogen receptor-negative breast cancer (χ(2)=17.407; P<0.0001). Tumor histological grade, in addition to TS and GST-π expression, were significant predictors of a poor survival outcome. TS and GST-π are consequently useful prognostic biomarkers in IDC, therefore, when establishing a personalized

  2. P-glycoprotein and its inducible expression in three bivalve species after exposure to Prorocentrum lima.

    PubMed

    Huang, Lu; Liu, Su-Li; Zheng, Jian-Wei; Li, Hong-Ye; Liu, Jie-Sheng; Yang, Wei-Dong

    2015-12-01

    P-glycoprotein (P-gp or ABCB1) belongs to the family of ATP-binding cassette (ABC) transporters responsible for multixenobiotic resistance (MXR) in aquatic organisms. To provide more information of P-gp in shellfish, in this study, complete cDNA of P-gp in three bivalve species including Ruditapes philippinarum, Scapharca subcrenata and Tegillarca granosa were cloned and its expressions in gill, digestive gland, adductor muscle and mantle of the three bivalves were detected after exposure to Prorocentrum lima, a toxogenic dinoflagellate. The complete sequences of R. philippinarum, S. subcrenata and T. granosa P-gp showed high homology with MDR/P-gp/ABCB proteins from other species, having a typical sequence organization as full transporters from the ABCB family. Phylogenetic analyses revealed that the amino acid sequences of P-gp from S. subcrenata and T. granosa had a closest relationship, forming an independent branch, then grouping into the other branch with Mytilus californianus, Mytilus galloprovincialis and Crassostrea gigas. However, P-gp sequences from R. philippinarum were more similar to the homologs from the more distantly related Aplysia californica than to homologs from S. subcrenata and T. granosa, suggesting that bivalves P-gp might have different paralogs. P-glycoprotein expressed in all detected tissues but there were large differences between them. After exposure to P. lima, the expression of P-gp changed in the four tissues in varying degrees within the same species and between different species, but the changes in mRNA and protein level were not always synchronous. PMID:26539802

  3. [Protein expression and purification].

    PubMed

    Růčková, E; Müller, P; Vojtěšek, B

    2014-01-01

    Production of recombinant proteins is essential for many applications in both basic research and also in medicine, where recombinant proteins are used as pharmaceuticals. This review summarizes procedures involved in recombinant protein expression and purification, including molecular cloning of target genes into expression vectors, selection of the appropriate expression system, and protein purification techniques. Recombinant DNA technology allows protein engineering to modify protein stability, activity and function or to facilitate protein purification by affinity tag fusions. A wide range of cloning systems enabling fast and effective design of expression vectors is currently available. A first choice of protein expression system is usually the bacteria Escherichia coli. The main advantages of this prokaryotic expression system are low cost and simplicity; on the other hand this system is often unsuitable for production of complex mammalian proteins. Protein expression mediated by eukaryotic cells (yeast, insect and mammalian cells) usually produces properly folded and posttranslationally modified proteins. How-ever, cultivation of insect and, especially, mammalian cells is time consuming and expensive. Affinity tagged recombinant proteins are purified efficiently using affinity chromatography. An affinity tag is a protein or peptide that mediates specific binding to a chromatography column, unbound proteins are removed during a washing step and pure protein is subsequently eluted. PMID:24945544

  4. Acetaminophen Modulates P-Glycoprotein Functional Expression at the Blood-Brain Barrier by a Constitutive Androstane Receptor–Dependent Mechanism

    PubMed Central

    Thompson, Brandon J.; Sanchez-Covarrubias, Lucy; Zhang, Yifeng; Laracuente, Mei-Li; Vanderah, Todd W.; Ronaldson, Patrick T.; Davis, Thomas P.

    2013-01-01

    Effective pharmacologic treatment of pain with opioids requires that these drugs attain efficacious concentrations in the central nervous system (CNS). A primary determinant of CNS drug permeation is P-glycoprotein (P-gp), an endogenous blood-brain barrier (BBB) efflux transporter that is involved in brain-to-blood transport of opioid analgesics (i.e., morphine). Recently, the nuclear receptor constitutive androstane receptor (CAR) has been identified as a regulator of P-gp functional expression at the BBB. This is critical to pharmacotherapy of pain/inflammation, as patients are often administered acetaminophen (APAP), a CAR-activating ligand, in conjunction with an opioid. Our objective was to investigate, in vivo, the role of CAR in regulation of P-gp at the BBB. Following APAP treatment, P-gp protein expression was increased up to 1.4–1.6-fold in a concentration-dependent manner. Additionally, APAP increased P-gp transport of BODIPY-verapamil in freshly isolated rat brain capillaries. This APAP-induced increase in P-gp expression and activity was attenuated in the presence of CAR pathway inhibitor okadaic acid or transcriptional inhibitor actinomycin D, suggesting P-gp regulation is CAR-dependent. Furthermore, morphine brain accumulation was enhanced by P-gp inhibitors in APAP-treated animals, suggesting P-gp–mediated transport. A warm-water (50°C) tail-flick assay revealed a significant decrease in morphine analgesia in animals treated with morphine 3 or 6 hours after APAP treatment, as compared with animals treated concurrently. Taken together, our data imply that inclusion of APAP in a pain treatment regimen activates CAR at the BBB and increases P-gp functional expression, a clinically significant drug-drug interaction that modulates opioid analgesic efficacy. PMID:24019224

  5. Reversal of P-gp and BCRP-mediated MDR by tariquidar derivatives.

    PubMed

    Li, Xu-Qin; Wang, Lin; Lei, Yan; Hu, Tao; Zhang, Fei-Long; Cho, Chi-Hin; To, Kenneth K W

    2015-08-28

    With an aim to generate non-toxic, specific and highly potent multidrug resistance (MDR) modulators, a novel series of anthranilic acid amide-substituted tariquidar derivatives were synthesized. The new compounds were evaluated for their cytotoxicity toward normal human colon fibroblasts (CCD18-Co), human gastric epithelial cell line (HFE) and primary rat liver cells, and for their ability to inhibit P-gp/BCRP-mediated drug efflux and reversal of P-gp and BCRP-mediated MDR in parental and drug-resistant cancer cell lines (LCC6 MDR1, MCF-7 FLV1000, R-HepG2, SW620-Ad300). While tariquidar is highly toxic to normal cells, the new derivatives exhibited much lower or negligible cytotoxicity. Some of the new tariquidar derivatives inhibited both P-gp and BCRP-mediated drug efflux whereas a few of them bearing a sulfonamide functional group (1, 5, and 16) are specific to P-gp. The new compounds were also found to potentiate the anticancer activity of the transporter substrate anticancer drugs in the corresponding transporter-overexpressing cell lines. The extent of resistance reversal was found to be consistent with the transporter inhibitory effect of the new derivatives. To further understand the mechanism of P-gp and BCRP inhibition, the tariquidar derivatives were found to interact with the transporters using an antibody-based UIC2 or 5D3 shift assay. Moreover, the transporters-inhibiting derivatives were found to modulate the ATPase activities of the two MDR transporters. Our data thus advocate further development of the new compounds for the circumvention of MDR. PMID:26197160

  6. Interaction of BDE-47 and its Hydroxylated Metabolite 6-OH-BDE-47 with the Human ABC Efflux Transporters P-gp and BCRP: Considerations for Human Exposure and Risk Assessment

    EPA Science Inventory

    ATP binding cassette (ABC) transporters, including P-glycoprotein (P-gp; also known as MDR1, ABCB1) and breast cancer resistance protein (BCRP; also known as ABCG2), are membrane-bound proteins that mediate the cellular efflux of xenobiotics as an important defense against chemic...

  7. Liquid Chromatographic Method for Irinotecan Estimation: Screening of P-gp Modulators

    PubMed Central

    Tariq, M.; Negi, L. M.; Talegaonkar, Sushama; Ahmad, F. J.; Iqbal, Zeenat; Khan, A. M.

    2015-01-01

    The present work is aimed to develop a simple, sensitive, robust and reliable HPLC method for the estimation of irinotecan in the physiological media in order to assess the permeability profile of irinotecan, using the everted gut sac, in the presence of various P-gp modulators. Separation was achieved using, C18 column with mobile phase consisting of acetonitrile and 0.045 µM sodium dihydrogen phosphate dihydrate buffer containing ion pair agent heptane sulphonic acid sodium salt (0.0054 µM), pH 3. The flow rate was maintained at 1 ml/min and analysis was performed at 254.9 nm using PDA detector. Calibration data showed an excellent linear relationship between peak-area verses drug concentration (r2, 0.9999). Linearity was found to be in the range of 0.060-10.0 µg/ml. Limits of detection and quantification were found to ~0.020 µg/ml and ~0.060 µg/ml, respectively. The developed method was found to be precise (RSD < 1.5%, for repeatability and <2.55% for intermediate precision, acceptable ranges of precision), accurate (The recovered content of irinotecan in the presence of various P-gp modulators varied from 96.11-101.51%, within acceptable range, 80-120%), specific and robust (% RSD < 2). Developed method has been applied successfully for the evaluation of eleven P-gp modulators from diverse chemical class. PMID:25767314

  8. Casein Kinase 2 (CK2)-mediated Phosphorylation of Hsp90β as a Novel Mechanism of Rifampin-induced MDR1 Expression*

    PubMed Central

    Kim, So Won; Hasanuzzaman, Md.; Cho, Munju; Heo, Ye Rang; Ryu, Min-Jung; Ha, Na-Young; Park, Hyun June; Park, Hyung-Yeon; Shin, Jae-Gook

    2015-01-01

    The P-glycoprotein (P-gp) encoded by the MDR1 gene is a drug-exporting transporter located in the cellular membrane. P-gp induction is regarded as one of the main mechanisms underlying drug-induced resistance. Although there is great interest in the regulation of P-gp expression, little is known about its underlying regulatory mechanisms. In this study, we demonstrate that casein kinase 2 (CK2)-mediated phosphorylation of heat shock protein 90β (Hsp90β) and subsequent stabilization of PXR is a key mechanism in the regulation of MDR1 expression. Furthermore, we show that CK2 is directly activated by rifampin. Upon exposure to rifampin, CK2 catalyzes the phosphorylation of Hsp90β at the Ser-225/254 residues. Phosphorylated Hsp90β then interacts with PXR, causing a subsequent increase in its stability, leading to the induction of P-gp expression. In addition, inhibition of CK2 and Hsp90β enhances the down-regulation of PXR and P-gp expression. The results of this study may facilitate the development of new strategies to prevent multidrug resistance and provide a plausible mechanism for acquired drug resistance by CK2-mediated regulation of P-gp expression. PMID:25995454

  9. Fullerene inhibits benzo(a)pyrene Efflux from Cyprinus carpio hepatocytes by affecting cell membrane fluidity and P-glycoprotein expression.

    PubMed

    Chen, Qiqing; Hu, Xialin; Wang, Rui; Yuan, Jin; Yin, Daqiang

    2016-05-01

    P-Glycoprotein (P-gp) can protect cells by pumping out toxic compounds, and has been found widely expressed in fish tissues. Here, we illustrate the P-gp efflux ability for benzo(a)pyrene (BaP) in the hepatocytes of common carp (Cyprinus carpio) after exposing to fullerene aqueous suspension (nC60). The results revealed that nC60 increased the membrane fluidity by decreasing the ratio of saturated to unsaturated fatty acids, and increased the cholesterol contents. These findings, combined with 10-38% and 70-75% down-regulation of P-gp mRNA and protein respectively, suggested that nC60 caused inhibition on P-gp efflux transport system. Therefore, we further investigated the cellular efflux ability for BaP. Results showed unequivocally that nC60 is a potent P-gp inhibitor. The retaining BaP amounts after efflux were elevated by 1.7-2.8 fold during the 10 day exposure. Meanwhile, 5mg/L humic acid (one of the important fractions of natural organic matter, which is ubiquitous in aquatic environment) alleviated the nC60 damage to hepatocytes in terms of oxidative damage, cholesterol increment, and P-gp content reduction; and finally attenuated the suppressed P-gp efflux ability. Collectively, this study provides the first evidence of nC60 toxicity to P-gp functionality in fish and illustrates the possible mechanism of the suppressed P-gp efflux ability for BaP. PMID:26918948

  10. P-glycoprotein expression and localization in the rat uterus throughout gestation and labor.

    PubMed

    Huang, Qi-Tao; Shynlova, Oksana; Kibschull, Mark; Zhong, Mei; Yu, Yan-Hong; Matthews, Stephen G; Lye, Stephen J

    2016-09-01

    Uterine tissues contain the efflux transporter P-glycoprotein (P-gp, encoded by Abcb1a/1b gene), but little is known about how it changes through gestation. Our aim was to investigate the expression profile and cellular localization of P-gp in the pregnant, laboring and post-partum (PP) rat uterus. We propose that during pregnancy the mechanical and hormonal stimuli play a role in regulating myometrial Abcb1a/1b/P-gp. Samples from bilaterally and unilaterally pregnant rats were collected throughout gestation, during labor, and PP (n=4-6/gestational day). RNA and protein were isolated and subjected to quantitative PCR and immunoblotting; P-gp transcript and protein were localized by in situ hybridization and immunohistochemistry. Expression of Abcb1a/1b gene and membrane P-gp protein in uterine tissue (1) increased throughout gestation, peaked at term (GD19-21) and dropped during labor (GD23L); and (2) was upregulated only in gravid but not in empty horn of unilaterally pregnant rats. (3) The drop of Abcb1a/1b mRNA on GD23 was prevented by artificial maintenance of elevated progesterone (P4) levels in late gestation; (4) injection of the P4 receptor antagonist RU486 on GD19 caused a significant decrease in Abcb1 mRNA levels. (5) In situ hybridization and immunohistochemistry indicated that Abcb1/P-gp is absent from myometrium throughout gestation; (6) was expressed exclusively by uterine microvascular endothelium (at early gestation) and luminal epithelium (at mid and late gestation), but was undetectable during labor. In conclusion, ABC transporter protein P-gp in pregnant uterus is hormonally and mechanically regulated. However, its substrate(s) and precise function in these tissues during pregnancy remains to be determined. PMID:27335130

  11. Inhibitory effect of clemastine on P-glycoprotein expression and function: an in vitro and in situ study

    PubMed Central

    Abbasi, Mehran Mesgari; Valizadeh, Hadi; Hamishekar, Hamed; Mohammadnejad, Leila; Zakeri-Milani, Parvin

    2016-01-01

    Objective(s): Transporters have an important role in pharmacokinetics of drugs. Inhibition or induction of drug transporters activity can affect drug absorption, safety, and efficacy. P-glycoprotein (P-gp) is the most important membrane transporter that is responsible for active efflux of drugs. It is important to understand which drugs are substrates, inhibitors, or inducers of P-gp to minimize or avoid unwanted interactions. The aim of this study was to investigate the effects of clemastine on the expression and function of P-gp. Materials and Methods: The effect of clemastine on P-gp function and expression was evaluated in vitro byrhodamine-123 (Rho123) efflux assay in Caco-2 cells and Western blot analysis. Rat in situ single pass intestinal permeability model was used to investigate the clemastine effect on digoxin Peff, as a known P-gp substrate. Digoxin levels in intestinal perfusates were assayed by high performance liquid chromatography (HPLC) method. Results: The Caco-2 intracellular accumulation of Rho123 in clemastine and verapamil treated cells was 90.8 ± 9.8 and 420.6±25.4 pg/mg protein, respectively which was significantly higher than that in control cells (50.2±6.0; P<0.05). Immunoblotting results indicated that clemastine decreased expression of P-gp in Caco-2 cells in vitro. More over effective intestinal permeability (Peff) of digoxin in the presence of clemastine, was significantly increased compare to control group. Conclusion: Findings of our study suggested dose dependent P-gp inhibition activity for clemastine in vitro and in situ. Therefore co-administration of clemastine with P-gp substrates may result in unwanted interactions and side effects. PMID:27279987

  12. Deactivation of Signal Transducer and Activator of Transcription 3 Reverses Chemotherapeutics Resistance of Leukemia Cells via Down-Regulating P-gp

    PubMed Central

    Zhang, Xulong; Xiao, Weihua; Wang, Lihua; Tian, Zhigang; Zhang, Jian

    2011-01-01

    Multidrug resistance (MDR) caused by overexpression of p-glycoprotein is a major obstacle in chemotherapy of malignant cancer, which usually is characterized by constitutive activation of signal transducer and activator of transcription 3 (STAT3), but their relation between MDR and STAT3 remains unclear. Here, we showed that STAT3 was overexpressed and highly activated in adriamycin-resistant K562/A02 cells compared with its parental K562 cells. Blockade of activation of STAT3 by STAT3 decoy oligodeoxynucleotide (ODN) promoted the accumulation and increased their sensitivity to adriamycin by down-regulating transcription of mdr1 and expression of P-gp, which were further confirmed by using STAT3-specific inhibitor JSI-124. Inhibition of STAT3 could also decrease mdr1 promoter mediated luciferase expression by using mdr1 promoter luciferase reporter construct. Otherwise, activation of STAT3 by STAT3C improved mdr1 transcription and P-gp expression. The ChIP results demonstrated that STAT3 could bind to the potential promoter region of mdr1, and STAT3 decoy depressed the binding. Further mutation assay show +64∼+72 region could be the STAT3 binding site. Our data demonstrate a role of STAT3 in regulation of mdr1 gene expression in myeloid leukemia and suggest that STAT3 may be a promising therapeutic target for overcoming MDR resistance in myeloid leukemia. PMID:21677772

  13. Reversing of multidrug resistance breast cancer by co-delivery of P-gp siRNA and doxorubicin via folic acid-modified core-shell nanomicelles.

    PubMed

    Wu, Yang; Zhang, Yu; Zhang, Wei; Sun, Chunlong; Wu, Jianzhong; Tang, Jinhai

    2016-02-01

    Multidrug resistance (MDR) remains one of major limitation for the successful treatment of many cancers including breast cancer. Co-delivery of chemotherapeutic drugs and small interfering RNA (siRNA) has been developed because of its ability to generate synergistic anticancer effects via different mechanisms of action, to reverse MDR and increase the efficacy of chemotherapeutic drugs in cancer therapy. Herein, we employed a kind of efficient multifunctional tumor targeted nanomicelles (PECL3) for the co-delivery of hydrophobic anti-cancer drugs and siRNA. This kind of nanomicelles were constructed by folic acid (FA)-decorated PEG-b-(PCL-g-PEI)-b-PCL triblock copolymers, which were synthesized through "click chemistry" and "ring opening" polymerization. Driven by the "core-shell" structure and the electrostatic interaction, this triblock copolymer could efficiently encapsulate P-glycoprotein (P-gp) siRNA and doxorubicin (DOX). The obtained nanomicelles can prevent renal clearance, RNase degradation and aggregation in circulation. Compared to the non-specific delivery, these FA functionalized nanomicelles could efficiently deliver P-gp siRNA to reducing both P-gp expression levels and IC50 value of the DOX in DOX-resistant breast cancer cells (MCF-7/ADR). Additionally, in vivo results showed that DOX loaded PECL3 (D-PECL3) micelles could reduce toxicity of DOX on nontarget tissues and significantly inhibited MCF-7/ADR tumor growth through encapsulating DOX in the micelles and deliver them to target tumor region. Taken together, these results proof that PECL3 micelles could co-deliver siRNA and drug to inhibit MDR tumor growth. These results suggested that the co-delivery of DOX and siRNA in tumor-targeting nanomicelles could excite synergistic effect of gene therapy and chemotherapy, thus can efficiently reverse MDR cancer and kill the cancer cells. PMID:26655793

  14. Expression and significance of hypoxia-inducible factor-1α and MDR1/P-glycoprotein in laryngeal carcinoma tissue and hypoxic Hep-2 cells

    PubMed Central

    XIE, JIN; LI, DA-WEI; CHEN, XIN-WEI; WANG, FEI; DONG, PIN

    2013-01-01

    The present study aimed to evaluate the expression of hypoxia-inducible factor-1α (HIF-1α) and MDR1/P-glycoprotein (P-gp) in human laryngeal squamous cell carcinoma (LSCC) tissues, and also to investigate the regulation of MDR1 gene expression by HIF-1α in Hep-2 cells under hypoxic conditions. The expression of HIF-1α and MDR1/P-gp in human LSCC tissues was examined using immunohistochemistry. The HIF-1α and MDR1 gene expression in the Hep-2 cells was detected using real-time quantitative reverse transcription (QRT)-PCR and western blot analysis under normoxic and hypoxic conditions. In hypoxia, HIF-1α expression was inhibited by RNA interference. HIF-1α and MDR1/P-gp expression was high in the LSCC tissues and was associated with the clinical stage and lymph node metastasis (P<0.05). HIF-1α expression was positively correlated with MDR1/P-gp expression (P<0.01). In the Hep-2 cells, HIF-1α and MDR1/P-gp expression significantly increased in response to hypoxia. The inhibition of HIF-1α expression synergistically downregulated the expression of the MDR1 gene in hypoxic Hep-2 cells. HIF-1α expression is positively correlated with MDR1/P-gp expression in LSCC, and the two proteins may be able to serve as potential biomarkers for predicting the malignant progression and metastasis of LSCC. HIF-1α may be critical for the upregulation of MDR1 gene expression induced by hypoxia in Hep-2 cells. PMID:23946810

  15. Leptospira Protein Expression During Infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We are characterizing protein expression in vivo during experimental leptospirosis using immunofluorescence microscopy. Coding regions for several proteins were identified through analysis of Leptospira interrogans serovar Copenhageni and L. borgpetersenii serovar Hardjo genomes. In addition, codi...

  16. A study comparing the efficacy of antimicrobial agents versus enzyme (P-gp) inducers in the treatment of 2,4,6 trinitrobenzenesulfonic acid-induced colitis in rats.

    PubMed

    Toklu, H Z; Kabasakal, L; Imeryuz, N; Kan, B; Celikel, C; Cetinel, S; Orun, O; Yuksel, M; Dulger, G A

    2013-08-01

    The intestinal microflora is an important cofactor in the pathogenesis of intestinal inflammation; and the epithelial cell barrier function is critical in providing protection against the stimulation of mucosal immune system by the microflora. In the present study, therapeutic role of the antibacterial drugs rifampicin and ciprofloxacine were investigated in comparison to spironolactone, an enzyme inducer, in 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis of the rats. Drugs were administered for 14 days following induction of colitis. All drug treatments ameliorated the clinical hallmarks of colitis as determined by body weight loss and assessment of diarrhea, colon length, and histology. Oxidative damage and neutrophil infiltration as well as nuclear factor κB (NF-κB) and tumor necrosis factor α (TNF-α) expressions that were increased during colitis, were decreased significantly. Rifampicin and ciprofloxacin were probably effective due to their antibacterial and immunomodulating properties. The multidrug resistence gene (MDR1) and its product p-glycoprotein (P-gp) has been implicated in the pathogenesis of inflammatory bowel disease (IBD). In the present study, findings of the P-gp expression were inconclusive but regarding previous studies, it can be suggested that the beneficial effects of rifampicin and spironolactone may be partly due to their action as a P-gp ligand. Spironolactone has been reported to supress the transcription of proinflamatory cytokines that are considered to be of importance in immunoinflammatory diseases. It is also a powerful pregnane X receptor (PXR) inducer; thus, inhibition of the expression of NF-κB and TNF-α, and amelioration of inflammation by spironolactone suggest that this may have been through the activation of PXR. However, our findings regarding PXR expression were inconclusive. Activation of PXR by spironolactone probably also contributed to the induction of P-gp, resulting in extrusion of noxious substances

  17. Abraxane, the Nanoparticle Formulation of Paclitaxel Can Induce Drug Resistance by Up-Regulation of P-gp

    PubMed Central

    Bu, Xiangli; Ma, Huailei; Gong, He; Liu, Juan; Fang, Xiangdong; Hu, Zhiyuan; Fang, Qiaojun

    2015-01-01

    P-glycoprotein (P-gp) can actively pump paclitaxel (PTX) out of cells and induces drug resistance. Abraxane, a nanoparticle (NP) formulation of PTX, has multiple clinical advantages over the single molecule form. However, it is still unclear whether Abraxane overcomes the common small molecule drug resistance problem mediated by P-gp. Here we were able to establish an Abraxane-resistant cell line from the lung adenocarcinoma cell line A549. We compared the transcriptome of A549/Abr resistant cell line to that of its parental cell line using RNA-Seq technology. Several pathways were found to be up or down regulated. Specifically, the most significantly up-regulated gene was ABCB1, which translates into P-glycoprotein. We verified the overexpression of P-glycoprotein and confirmed its function by reversing the drug resistance with P-gp inhibitor Verapamil. The results suggest that efflux pathway plays an important role in the Abraxane-resistant cell line we established. However, the relevance of this P-gp mediated Abraxane resistance in tumors of lung cancer patients remains unknown. PMID:26182353

  18. Abraxane, the Nanoparticle Formulation of Paclitaxel Can Induce Drug Resistance by Up-Regulation of P-gp.

    PubMed

    Zhao, Minzhi; Lei, Chunni; Yang, Yadong; Bu, Xiangli; Ma, Huailei; Gong, He; Liu, Juan; Fang, Xiangdong; Hu, Zhiyuan; Fang, Qiaojun

    2015-01-01

    P-glycoprotein (P-gp) can actively pump paclitaxel (PTX) out of cells and induces drug resistance. Abraxane, a nanoparticle (NP) formulation of PTX, has multiple clinical advantages over the single molecule form. However, it is still unclear whether Abraxane overcomes the common small molecule drug resistance problem mediated by P-gp. Here we were able to establish an Abraxane-resistant cell line from the lung adenocarcinoma cell line A549. We compared the transcriptome of A549/Abr resistant cell line to that of its parental cell line using RNA-Seq technology. Several pathways were found to be up or down regulated. Specifically, the most significantly up-regulated gene was ABCB1, which translates into P-glycoprotein. We verified the overexpression of P-glycoprotein and confirmed its function by reversing the drug resistance with P-gp inhibitor Verapamil. The results suggest that efflux pathway plays an important role in the Abraxane-resistant cell line we established. However, the relevance of this P-gp mediated Abraxane resistance in tumors of lung cancer patients remains unknown. PMID:26182353

  19. Does the Clearance of Inhaled (99m)Tc-Sestamibi Correlate with Multidrug Resistance Protein 1 Expression in the Human Lung?

    PubMed

    Mohan, Hosahalli K; Routledge, Thomas; Cane, Paul; Livieratos, Lefteris; Ballinger, James R; Peters, Adrien M

    2016-09-01

    Purpose To examine the relation between the lung elimination rate of inhaled technetium 99m ((99m)Tc)-sestamibi and immunohistochemical expression of bronchopulmonary multidrug resistance protein 1 (MRP1) and permeability glycoprotein (P-gp) and assess the repeatability of the inhaled (99m)Tc-sestamibi clearance technique. Materials and Methods (99m)Tc-sestamibi is a known substrate for P-gp and MRP1, which are established cellular drug efflux transporters. The elimination rate of (99m)Tc-sestamibi from the lungs after inhalation as an aerosol has been hypothesized to be regulated by expression of these transporters. Institutional ethics committee approval was received for this prospective study. Written informed consent was obtained from all participants. The clearance of inhaled (99m)Tc-sestamibi from the lungs of 13 patients due to undergo surgery for primary lung cancer (five of 13) or spontaneous pneumothorax (eight of 13) was estimated after dynamic imaging of the lungs during a period of 40 minutes. The time taken to clear 50% of inhaled sestamibi (T1/2) was compared with a semiquantitative immunohistochemical assessment (grade 0-3) of MRP1 and P-gp expression in the lung by using parametric and nonparametric tests. The study was repeated in five participants to assess the repeatability of the technique by using a Bland Altman analysis method. Results MRP1 expression was seen in 12 of 13 patients, while P-gp expression was seen in only two. The mean (99m)Tc-sestamibi elimination rate was faster in patients (n = 6) with low levels of MRP1 expression (grade 0-1) and mean T1/2 of 105 minutes ± 20 (standard deviation), compared with those with higher levels of MRP1 expression (grade 2-3, n = 7) and mean T1/2 of 149 minutes ± 28 (P = .008). Bland-Altman analysis revealed excellent agreement between test and retest values. Conclusion Inhaled (99m)Tc-sestamibi clearance study is a repeatable technique demonstrating significant correlation with MRP1 expression in

  20. Forced expression of heat shock protein 27 (Hsp27) reverses P-glycoprotein (ABCB1)-mediated drug efflux and MDR1 gene expression in Adriamycin-resistant human breast cancer cells.

    PubMed

    Kanagasabai, Ragu; Krishnamurthy, Karthikeyan; Druhan, Lawrence J; Ilangovan, Govindasamy

    2011-09-23

    Mutant p53 accumulation has been shown to induce the multidrug resistance gene (MDR1) and ATP binding cassette (ABC)-based drug efflux in human breast cancer cells. In the present work, we have found that transcriptional activation of the oxidative stress-responsive heat shock factor 1 (HSF-1) and expression of heat shock proteins, including Hsp27, which is normally known to augment proteasomal p53 degradation, are inhibited in Adriamycin (doxorubicin)-resistant MCF-7 cells (MCF-7/adr). Such an endogenous inhibition of HSF-1 and Hsp27 in turn results in p53 mutation with gain of function in its transcriptional activity and accumulation in MCF-7/adr. Also, lack of HSF-1 enhances nuclear factor κB (NF-κB) DNA binding activity together with mutant p53 and induces MDR1 gene and P-glycoprotein (P-gp, ABCB1), resulting in a multidrug-resistant phenotype. Ectopic expression of Hsp27, however, significantly depleted both mutant p53 and NF-κB (p65), reversed the drug resistance by inhibiting MDR1/P-gp expression in MCF-7/adr cells, and induced cell death by increased G(2)/M population and apoptosis. We conclude from these results that HSF-1 inhibition and depletion of Hsp27 is a trigger, at least in part, for the accumulation of transcriptionally active mutant p53, which can either directly or NF-κB-dependently induce an MDR1/P-gp phenotype in MCF-7 cells. Upon Hsp27 overexpression, this pathway is abrogated, and the acquired multidrug resistance is significantly abolished so that MCF-7/adr cells are sensitized to Dox. Thus, clinical alteration in Hsp27 or NF-κB level will be a potential approach to circumvent drug resistance in breast cancer. PMID:21784846

  1. Nanolipoparticles-mediated MDR1 siRNA delivery reduces doxorubicin resistance in breast cancer cells and silences MDR1 expression in xenograft model of human breast cancer

    PubMed Central

    Nourbakhsh, Mahnaz; Jaafari, Mahmoud Reza; Lage, Hermann; Abnous, Khalil; mosaffa, Fatemeh; Badiee, Ali; Behravan, Javad

    2015-01-01

    Objective(s): P-glycoprotein (P-gp) is an efflux protein, the overexpression of which has been associated with multidrug resistance in various cancers. Although siRNA delivery to reverse P-gp expression may be promising for sensitizing of tumor cells to cytotoxic drugs, the therapeutic use of siRNA requires effective carriers that can deliver siRNA intracellularly with minimal toxicity on target cells. We investigated a special class of PEGylated lipid-based nanoparticles (NP), named nanolipoparticles (NLPs), for siRNA-mediated P-gp downregulation. Materials and Methods: NLPs were prepared based on low detergent dialysis method. After characterization, we evaluated the effect of NLPs on siRNA delivery, and P-gp downregulation compared to oligofectamine™ (OFA) in vitro and in vivo. Results: Our results showed a significant decrease in P-gp expression and subsequent enhancement of chemosensitivity to doxorubicin in vitro. Although the effectiveness of NLPs for in vitro siRNA delivery compared to OFA was limited, the results of in vivo studies showed noticeable effectiveness of NLPs for systemic siRNA delivery. siRNA delivery using NLPs could downregulate MDR1 in tumor cells more than 80%, while OFA had a reverse effect on MDR1 expression in vivo. Conclusion: The results indicated that the prepared NLPs could be suitable siRNA delivery systems for tumor therapy. PMID:26019802

  2. 4,5-Di-substituted benzyl-imidazol-2-substituted amines as the structure template for the design and synthesis of reversal agents against P-gp-mediated multidrug resistance breast cancer cells.

    PubMed

    Zhang, Nan; Zhang, Zhaohui; Wong, Iris L K; Wan, Shengbiao; Chow, Larry M C; Jiang, Tao

    2014-08-18

    Over-expression of P-glycoprotein (P-gp), a primary multidrug transporter which is located in plasma membranes, plays a major role in the multidrug resistance (MDR) of cytotoxic chemotherapy. Naamidines are a class of marine imidazole alkaloids isolated from Leucetta and Clathrina sponges, possessing a Y-shaped scaffold. Based on the results previously obtained from the third-generation MDR modulator ONT-093 and other modulators developed in our group, we designed and synthesized a series of novel 4,5-di-substituted benzyl-1-methyl-1H-imidazol-2-substituted amines using the Naamidine scaffold as the structure template. Subsequently, their reversing activity for Taxol resistance has been evaluated in P-gp-mediated multidrug resistance breast cancer cell line MDA435/LCC6MDR. Compounds 12c with a Y-shaped scaffold, and compound 17c which is 'X-shaped' scaffold and possesses a 4-diethylamino group at aryl ring B, turned out to be the most potent P-gp modulators. It appears that compounds 12c and 17c at 1 μM concentration can sensitize LCC6MDR cells toward Taxol by 26.4 and 24.5 folds, with an EC50 212.5 and 210.5 nM, respectively. These two compounds are about 5-6 folds more potent than verapamil (RF = 4.5). Moreover, compounds 12c and 17c did not exhibit obvious cytotoxicity in either cancer cell lines or normal mouse fibroblast cell lines. This study has demonstrated that the synthetic Naamidine analogues can be potentially employed as effective, safe modulators for the P-gp-mediated drug resistance cancer cells. PMID:24952376

  3. In Silico Quantitative Structure-Activity Relationship Studies on P-gp Modulators of Tetrahydroisoquinoline-Ethyl-Phenylamine Series

    PubMed Central

    2011-01-01

    Background Multidrug resistance (MDR) is a major obstacle in cancer chemotherapy. The drug efflux by a transport protein is the main reason for MDR. In humans, MDR mainly occurs when the ATP-binding cassette (ABC) family of proteins is overexpressed simultaneously. P-glycoprotein (P-gp) is most commonly associated with human MDR; it utilizes energy from adenosine triphosphate (ATP) to transport a number of substrates out of cells against concentration gradients. By the active transport of substrates against concentration gradients, intracellular concentrations of substrates are decreased. This leads to the cause of failure in cancer chemotherapy. Results Herein, we report Topomer CoMFA (Comparative Molecular Field Analysis) and HQSAR (Hologram Quantitative Structure Activity Relationship) models for third generation MDR modulators. The Topomer CoMFA model showed good correlation between the actual and predicted values for training set molecules. The developed model showed cross validated correlation coefficient (q2) = 0.536 and non-cross validated correlation coefficient (r2) = 0.975 with eight components. The best HQSAR model (q2 = 0.777, r2 = 0.956) with 5-8 atom counts was used to predict the activity of test set compounds. Both models were validated using test set compounds, and gave a good predictive values of 0.604 and 0.730. Conclusions The contour map near R1 indicates that substitution of a bulkier and polar group to the ortho position of the benzene ring enhances the inhibitory effect. This explains why compounds with a nitro group have good inhibitory potency. Molecular fragment analyses shed light on some essential structural and topological features of third generation MDR modulators. Fragments analysis showed that the presence of tertiary nitrogen, a central phenyl ring and an aromatic dimethoxy group contributed to the inhibitory effect. Based on contour map information and fragment information, five new molecules with variable R1 substituents were

  4. Induction of multidrug resistance downregulates the expression of CFTR in colon epithelial cells.

    PubMed

    Breuer, W; Slotki, I N; Ausiello, D A; Cabantchik, I Z

    1993-12-01

    The epithelial cell line HT-29, which constitutively expresses the cystic fibrosis transmembrane conductance regulator (CFTR), was induced to become drug resistant by cultivation in the presence of colchicine. The gradual acquisition of drug resistance was associated with a corresponding increase in the expression of the multidrug resistance P-glycoprotein (P-gp) and a marked (> 80%) decrease in the constitutive levels of CFTR protein, as determined by immunoblotting. The reduction in CFTR content occurred at the onset of acquisition of drug resistance when P-gp expression was still relatively low. Reversal of drug resistance by removal of colchicine from the culture medium led to a 70% decrease in P-gp levels and a concomitant 40% increase in CFTR. The levels of other membrane proteins such as Na(+)-K(+)-ATPase and alkaline phosphatase remained relatively constant (< 26% variation). We propose that a selective downregulation of CFTR is elicited by acquisition of the multidrug resistance (MDR) phenotype and that induction of P-gp expression leads to a reversible repression of CFTR biosynthesis. These findings provide an experimental foundation for the complementary patterns of expression of the CFTR and MDR1 genes observed in vivo. PMID:7506492

  5. Influence of overexpression of efflux proteins on the function and gene expression of endogenous peptide transporters in MDR-transfected MDCKII cell lines.

    PubMed

    Wang, Zhiying; Pal, Dhananjay; Patel, Ashaben; Kwatra, Deep; Mitra, Ashim K

    2013-01-30

    The objective of this study is to delineate whether overexpression of human efflux transporters (P-gp, MRP2, and BCRP) in transfected MDCK cells affect the functional activities, and gene and protein expression of endogenous influx peptide transporter system (PepT). Real-time PCR, immunoblotting, uptake and permeability studies of [(3)H]Gly-Sar were conducted on transfected MDCKII and wild-type cells to investigate functional differences. Cellular [(3)H]Gly-Sar accumulation was significantly lower in transfected MDCKII cell lines compared to wild-type cells. Transport efficiency of apical peptide transporters was markedly reduced to around 25%, 30%, and 40% in P-gp-, MRP2-, and BCRP-overexpressed MDCK cell lines, respectively. With ascending cell-passage, transport efficiency was enhanced. A significantly higher Gly-Sar permeability was observed across parental cell-monolayers over transfected cells at all pHs. Levels of mRNA for both canine PepT1 and PepT2 were substantially reduced when efflux transporters overexpressed but enhanced when mRNA-levels of efflux genes diminished with ascending cell-passage of transfected cells. An inverse correlation was evident between endogenous PepT and exogenous efflux transporters in transfected MDCKII cells. Results of protein expression also supported these findings. Overexpression of MDR genes can affect endogenous PepT function which might be due to the phenomenon of transporter-compensation resulting in down-regulation of endogenous genes. PMID:23262422

  6. Influence of overexpression of efflux proteins on the function and gene expression of endogenous peptide transporters in MDR-transfected MDCKII cell lines

    PubMed Central

    Wang, Zhiying; Pal, Dhananjay; Patel, Ashaben; Kwatra, Deep; Mitra, Ashim K.

    2013-01-01

    The objective of this study is to delineate whether overexpression of human efflux transporters (P-gp, MRP2, and BCRP) in transfected MDCK cells affect the functional activities, and gene and protein expression of endogenous influx peptide transporter system (PepT). Real-time PCR, immunoblotting, uptake and permeability studies of [3H]Gly-Sar were conducted on transfected MDCKII and wild-type cells to investigate functional differences. Cellular [3H]Gly-Sar accumulation was significantly lower in transfected MDCKII cell lines compared to wild-type cells. Transport efficiency of apical peptide transporters was markedly reduced to around 25%, 30%, and 40% in P-gp-, MRP2-, and BCRP-overexpressed MDCK cell lines, respectively. With ascending cell-passage, transport efficiency was enhanced. A significantly higher Gly-Sar permeability was observed across parental cell-monolayers over transfected cells at all pHs. Levels of mRNA for both canine PepT1 and PepT2 were substantially reduced when efflux transporters overexpressed but enhanced when mRNA-levels of efflux genes diminished with ascending cell-passage of transfected cells. An inverse correlation was evident between endogenous PepT and exogenous efflux transporters in transfected MDCKII cells. Results of protein expression also supported these findings. Overexpression of MDR genes can affect endogenous PepT function which might be due to the phenomenon of transporter-compensation resulting in down-regulation of endogenous genes. PMID:23262422

  7. Immunocytochemical detection of the multidrug resistance-associated protein and P-glycoprotein in acute myeloid leukemia: impact of antibodies, sample source and disease status.

    PubMed

    Filipits, M; Suchomel, R W; Lechner, K; Pirker, R

    1997-07-01

    Immunocytochemical detection of the expression of the MRP gene and the MDR1 gene in clinical specimens might be affected by several factors. Thus, we studied the impact of monoclonal antibodies, sample source (peripheral blood vs bone marrow) and disease status on the expression of multidrug resistance-associated protein (MRP) as well as P-glycoprotein (P-gp) in leukemic cells of patients with acute myeloid leukemia (AML). MRP expression was determined by means of anti-MRP antibodies (QCRL-1, QCRL-3, QCRL-1/QCRL-3 or MRPr1). In the case of P-gp, monoclonal antibodies C219 and MRK16 were used. High MRP expression ranged from 5 to 35% and high P-gp expression from 5 to 14% of the specimens. A fair correlation between results obtained with QCRL-1/QCRL-3 and those obtained with MRPr1, as well as a moderate correlation between C219 and MRK16, were seen. MRP and P-gp expression of peripheral blood blasts were similar to those of bone marrow blasts in the majority of cases. The degrees of MRP expression at the time of diagnosis were also similar to the degrees of expression at relapse, albeit an analysis of sequential MRP expression in 13 patients indicated an increase of expression at relapse in six patients as compared to the time of diagnosis. PMID:9204994

  8. Effects of brain IKKβ gene silencing by small interfering RNA on P-glycoprotein expression and brain damage in the rat kainic acid-induced seizure model.

    PubMed

    Yu, Nian; Liu, Hao; Zhang, Yan-Fang; Su, Ling-Ying; Liu, Xin-Hong; Li, Le-Chao; Hao, Jin-Bo; Huang, Xian-Jing; Di, Qing

    2014-01-01

    Multidrug resistance mediated by over-expression of P-glycoprotein (P-gp) in brain is an important mechanism accounting for the drug-therapy failure in epilepsy. Over-expression of P-gp in epilepsy rat brain may be regulated by inflammation and nuclear factor-kappa B (NF-κB) activation. Inhibitory κ B kinase subunit β (IKKβ) is an up-stream molecular controlling NF-κB activation. With the small interfering RNA (siRNA) technique and kainic acid (KA)-induced rat epileptic seizure model, the present study was aimed to further evaluate the role of NF-κB inhibition, via blocking IKKβ gene transcription, in the epileptic brain P-gp over-expression, seizure susceptibility, and post-seizure brain damage. siRNA targeting IKKβ was administered to rats via intracerebroventricular injection before seizure induction by KA microinjection; scrambled siRNA was used as control. Brain mRNA and protein levels of IKKβ and P-gp were detected by RT-PCR and immunohistochemistry. NF-κB activity was measured by electrophoretic mobility shift assay. Latency to grade III or V seizure onset was recorded, brain damage was evaluated by neuronal cell counting and epileptiform activity was monitored by electroencephalography. IKKβ siRNA pre-treatment inhibited NF-κB activation and abolished P-gp over-expression in KA-induced epileptic rat brain, accompanied by decreased seizure susceptibility. These findings suggested that epileptogenic-induced P-gp over-expression could be regulated by IKKβ through the NF-κB pathway. PMID:24040792

  9. Protein identification and Peptide expression resolver: harmonizing protein identification with protein expression data.

    PubMed

    Kearney, Paul; Butler, Heather; Eng, Kevin; Hugo, Patrice

    2008-01-01

    Proteomic discovery platforms generate both peptide expression information and protein identification information. Peptide expression data are used to determine which peptides are differentially expressed between study cohorts, and then these peptides are targeted for protein identification. In this paper, we demonstrate that peptide expression information is also a powerful tool for enhancing confidence in protein identification results. Specifically, we evaluate the following hypothesis: tryptic peptides originating from the same protein have similar expression profiles across samples in the discovery study. Evidence supporting this hypothesis is provided. This hypothesis is integrated into a protein identification tool, PIPER (Protein Identification and Peptide Expression Resolver), that reduces erroneous protein identifications below 5%. PIPER's utility is illustrated by application to a 72-sample biomarker discovery study where it is demonstrated that false positive protein identifications can be reduced below 5%. Consequently, it is recommended that PIPER methodology be incorporated into proteomic studies where both protein expression and identification data are collected. PMID:18062667

  10. Modeling Protein Expression and Protein Signaling Pathways

    PubMed Central

    Telesca, Donatello; Müller, Peter; Kornblau, Steven M.; Suchard, Marc A.; Ji, Yuan

    2015-01-01

    High-throughput functional proteomic technologies provide a way to quantify the expression of proteins of interest. Statistical inference centers on identifying the activation state of proteins and their patterns of molecular interaction formalized as dependence structure. Inference on dependence structure is particularly important when proteins are selected because they are part of a common molecular pathway. In that case, inference on dependence structure reveals properties of the underlying pathway. We propose a probability model that represents molecular interactions at the level of hidden binary latent variables that can be interpreted as indicators for active versus inactive states of the proteins. The proposed approach exploits available expert knowledge about the target pathway to define an informative prior on the hidden conditional dependence structure. An important feature of this prior is that it provides an instrument to explicitly anchor the model space to a set of interactions of interest, favoring a local search approach to model determination. We apply our model to reverse-phase protein array data from a study on acute myeloid leukemia. Our inference identifies relevant subpathways in relation to the unfolding of the biological process under study. PMID:26246646

  11. N-alkylated isatins evade P-gp mediated efflux and retain potency in MDR cancer cell lines.

    PubMed

    Vine, Kara L; Belfiore, Lisa; Jones, Luke; Locke, Julie M; Wade, Samantha; Minaei, Elahe; Ranson, Marie

    2016-01-01

    The search for novel anticancer therapeutics with the ability to overcome multi-drug resistance (MDR) mechanisms is of high priority. A class of molecules that show potential in overcoming MDR are the N-alkylated isatins. In particular 5,7-dibromo-N-alkylisatins are potent microtubule destabilizing agents that act to depolymerize microtubules, induce apoptosis and inhibit primary tumor growth in vivo. In this study we evaluated the ability of four dibrominated N-alkylisatin derivatives and the parent compound, 5,7-dibromoisatin, to circumvent MDR. All of the isatin-based compounds examined retained potency against the MDR cell lines; U937VbR and MES-SA/Dx5 and displayed bioequivalent dose-dependent cytotoxicity to that of the parental control cell lines. We show that one mechanism by which the isatin-based compounds overcome MDR is by circumventing P-glycoprotein (P-gp) mediated drug efflux. Thus, as the isatin-based compounds are not susceptible to extrusion from P-gp overexpressing tumor cells, they represent a promising alternative strategy as a stand-alone or combination therapy for treating MDR cancer. PMID:27441242

  12. Regulation of Multidrug Resistance Proteins by Genistein in a Hepatocarcinoma Cell Line: Impact on Sorafenib Cytotoxicity

    PubMed Central

    Rigalli, Juan Pablo; Ciriaci, Nadia; Arias, Agostina; Ceballos, María Paula; Villanueva, Silvina Stella Maris; Luquita, Marcelo Gabriel; Mottino, Aldo Domingo; Ghanem, Carolina Inés; Catania, Viviana Alicia; Ruiz, María Laura

    2015-01-01

    Hepatocellular carcinoma (HCC) is the fifth most frequent cancer worldwide. Sorafenib is the only drug available that improves the overall survival of HCC patients. P-glycoprotein (P-gp), Multidrug resistance-associated proteins 2 and 3 (MRP2 and 3) and Breast cancer resistance protein (BCRP) are efflux pumps that play a key role in cancer chemoresistance. Their modulation by dietary compounds may affect the intracellular accumulation and therapeutic efficacy of drugs that are substrates of these transporters. Genistein (GNT) is a phytoestrogen abundant in soybean that exerts its genomic effects through Estrogen-Receptors and Pregnane-X-Receptor (PXR), which are involved in the regulation of the above-mentioned transporters. We evaluated the effect of GNT on the expression and activity of P-gp, MRP2, MRP3 and BCRP in HCC-derived HepG2 cells. GNT (at 1.0 and 10 μM) increased P-gp and MRP2 protein expression and activity, correlating well with an increased resistance to sorafenib cytotoxicity as detected by the methylthiazole tetrazolium (MTT) assay. GNT induced P-gp and MRP2 mRNA expression at 10 but not at 1.0 μM concentration suggesting a different pattern of regulation depending on the concentration. Induction of both transporters by 1.0 μM GNT was prevented by cycloheximide, suggesting translational regulation. Downregulation of expression of the miR-379 by GNT could be associated with translational regulation of MRP2. Silencing of PXR abolished P-gp induction by GNT (at 1.0 and 10 μM) and MRP2 induction by GNT (only at 10 μM), suggesting partial mediation of GNT effects by PXR. Taken together, the data suggest the possibility of nutrient-drug interactions leading to enhanced chemoresistance in HCC when GNT is ingested with soy rich diets or dietary supplements. PMID:25781341

  13. [11C]phenytoin revisited: synthesis by [11C]CO carbonylation and first evaluation as a P-gp tracer in rats

    PubMed Central

    2012-01-01

    Background At present, several positron emission tomography (PET) tracers are in use for imaging P-glycoprotein (P-gp) function in man. At baseline, substrate tracers such as R-[11C]verapamil display low brain concentrations with a distribution volume of around 1. [11C]phenytoin is supposed to be a weaker P-gp substrate, which may lead to higher brain concentrations at baseline. This could facilitate assessment of P-gp function when P-gp is upregulated. The purpose of this study was to synthesize [11C]phenytoin and to characterize its properties as a P-gp tracer. Methods [11C]CO was used to synthesize [11C]phenytoin by rhodium-mediated carbonylation. Metabolism and, using PET, brain pharmacokinetics of [11C]phenytoin were studied in rats. Effects of P-gp function on [11C]phenytoin uptake were assessed using predosing with tariquidar. Results [11C]phenytoin was synthesized via [11C]CO in an overall decay-corrected yield of 22 ± 4%. At 45 min after administration, 19% and 83% of radioactivity represented intact [11C]phenytoin in the plasma and brain, respectively. Compared with baseline, tariquidar predosing resulted in a 45% increase in the cerebral distribution volume of [11C]phenytoin. Conclusions Using [11C]CO, the radiosynthesis of [11C]phenytoin could be improved. [11C]phenytoin appeared to be a rather weak P-gp substrate. PMID:22747744

  14. miR200c attenuates P-gp-mediated MDR and metastasis by targeting JNK2/c-Jun signaling pathway in colorectal cancer.

    PubMed

    Sui, Hua; Cai, Guo-Xiang; Pan, Shu-Fang; Deng, Wan-Li; Wang, Yu-Wei; Chen, Zhe-Sheng; Cai, San-Jun; Zhu, Hui-Rong; Li, Qi

    2014-12-01

    MicroRNA-200c (miR200c) recently emerged as an important regulator of tumorigenicity and cancer metastasis; however, its role in regulating multidrug resistance (MDR) remains unknown. In the current study, we found that the expression levels of miR200c in recurrent and metastatic colorectal cancers were significantly lower, whereas the JNK2 expression was higher compared with primary tumors. We showed that in MDR colorectal cancer cells, miR200c targeted the 3' untranslated region of the JNK2 gene. Overexpression of miR200c attenuated the levels of p-JNK, p-c-Jun, P-gp, and MMP-2/-9, the downstream factors of the JNK signaling pathway, resulting in increased sensitivity to chemotherapeutic drugs, which was accompanied by heightened apoptosis and decreased cell invasion and migration. Moreover, in an orthotopic MDR colorectal cancer mouse model, we demonstrated that overexpression of miR200c effectively inhibited the tumor growth and metastasis. At last, in the tumor samples from patients with locally advanced colorectal cancer with routine postsurgical chemotherapy, we observed an inverse correlation between the levels of mRNA expression of miR200c and JNK2, ABCB1, and MMP-9, thus predicting patient therapeutic outcomes. In summary, we found that miR200c negatively regulated the expression of JNK2 gene and increased the sensitivity of MDR colorectal cancer cells to chemotherapeutic drugs, via inhibiting the JNK2/p-JNK/p-c-Jun/ABCB1 signaling. Restoration of miR200c expression in MDR colorectal cancer may serve as a promising therapeutic approach in MDR-induced metastasis. PMID:25205654

  15. Reduced ABCB1 Expression and Activity in the Presence of Acrylic Copolymers

    PubMed Central

    Mohammadzadeh, Ramin; Baradaran, Behzad; Valizadeh, Hadi; Yousefi, Bahman; Zakeri-Milani, Parvin

    2014-01-01

    Purpose: P-glycoprotein (P-gp; ABCB1), an integral membrane protein in the apical surface of human intestinal epithelial cells, plays a crucial role in the intestinal transport and efflux leading to changes in the bioavailability of oral pharmaceutical compounds. This study was set to examine the potential effects of three Eudragits RL100, S100 and L100 on the intestinal epithelial membrane transport of rhodammine-123 (Rho-123), a substrate of P-gp using a monolayer of human colon cancer cell line (Caco-2). Methods: The least non-cytotoxic concentrations of the excipients were assessed in Caco-2 cells by the MTT assay. Then the transepithelial transport of Rho-123 across Caco-2 monolayers was determined with a fluorescence spectrophotometer. Besides, the expression of the P-gp in cells exposed to the polymers was demonstrated using Western-blotting analysis. Results: Treatment of cells with Eudragit RL100 and L100 led to a very slight change while Eudragit S100 showed 61% increase in Rho-123 accumulation (P<0.001) and also reduced transporter expression. Conclusion: Our studies suggest that using proper concentrations of the Eudragit S100 in drug formulation would improve intestinal permeability and absorption of p-gp substrate drugs. PMID:24754004

  16. Synthesis and Evaluation of [N-methyl-11C]N-Desmethyl-loperamide as a New and Improved PET Radiotracer for Imaging P-gp Function

    PubMed Central

    Lazarova, Neva; Zoghbi, Sami S.; Hong, Jinsoo; Seneca, Nicholas; Tuan, Ed; Gladding, Robert L.; Liow, Jeih-San; Taku, Andrew; Innis, Robert B.; Pike, Victor W.

    2009-01-01

    [11C]Loperamide has been proposed for imaging P-glycoprotein (P-gp) function with positron emission tomography (PET), but its metabolism to [N-methyl-11C]N-desmethyl-loperamide ([11C]dLop; [11C]3) precludes quantification. We considered that [11C]3 might itself be a superior radiotracer for imaging brain P-gp function and therefore aimed to prepare [11C]3 and characterize its efficacy. An amide precursor (2) was synthesized and methylated with [11C]iodomethane to give [11C]3. After administration of [11C]3 to wild type mice, brain radioactivity uptake was very low. In P-gp (mdr-1a (−/−)) knockout mice, brain uptake of radioactivity at 30 min increased about 3.5 fold by PET measures, and over seven-fold by ex vivo measures. In knockout mice, brain radioactivity was predominantly (90%) unchanged radiotracer. In monkey PET experiments, brain radioactivity uptake was also very low, but after P-gp blockade increased more than seven-fold. [11C]3 is an effective new radiotracer for imaging brain P-gp function and, in favor of future successful quantification, appears free of extensive brain-penetrant radiometabolites. PMID:18783208

  17. B4GALT family mediates the multidrug resistance of human leukemia cells by regulating the hedgehog pathway and the expression of p-glycoprotein and multidrug resistance-associated protein 1

    PubMed Central

    Zhou, H; Ma, H; Wei, W; Ji, D; Song, X; Sun, J; Zhang, J; Jia, L

    2013-01-01

    β-1, 4-Galactosyltransferase gene (B4GALT) family consists of seven members, which encode corresponding enzymes known as type II membrane-bound glycoproteins. These enzymes catalyze the biosynthesis of different glycoconjugates and saccharide structures, and have been recognized to be involved in various diseases. In this study, we sought to determine the expressional profiles of B4GALT family in four pairs of parental and chemoresistant human leukemia cell lines and in bone marrow mononuclear cells (BMMC) of leukemia patients with multidrug resistance (MDR). The results revealed that B4GALT1 and B4GALT5 were highly expressed in four MDR cells and patients, altered levels of B4GALT1 and B4GALT5 were responsible for changed drug-resistant phenotype of HL60 and HL60/adriamycin-resistant cells. Further data showed that manipulation of these two gene expression led to increased or decreased activity of hedgehog (Hh) signaling and proportionally mutative expression of p-glycoprotein (P-gp) and MDR-associated protein 1 (MRP1) that are both known to be related to MDR. Thus, we propose that B4GALT1 and B4GALT5, two members of B4GALT gene family, are involved in the development of MDR of human leukemia cells, probably by regulating the activity of Hh signaling and the expression of P-gp and MRP1. PMID:23744354

  18. Data Mining for Expressivity of Recombinant Protein Expression

    NASA Astrophysics Data System (ADS)

    Kira, Satoshi; Isoai, Atsushi; Yamamura, Masayuki

    We analyzed the expressivity of recombinant proteins by using data mining methods. The expression technique of recombinant protein is a key step towards elucidating the functions of genes discovered through genomic sequence projects. We have studied the productive efficiency of recombinant proteins in fission yeast, Schizosaccharomyces pombe (S.pombe), by mining the expression results. We gathered 57 proteins whose expression levels were known roughly in the host. Correlation analysis, principal component analysis and decision tree analysis were applied to these expression data. Analysis featuring codon usage and amino acid composition clarified that the amino acid composition affected to the expression levels of a recombinant protein strongly than the effect of codon usage. Furthermore, analysis of amino acid composition showed that protein solubility and the metabolism cost of amino acids correlated with a protein expressivity. Codon usage was often interesting in the field of recombinant expressions. However, our analysis found the weak correlation codon features with expressivities. These results indicated that ready-made indices of codon bias were irrelevant ones for modeling the expressivities of recombinant proteins. Our data driven approach was an easy and powerful method to improve recombinant protein expression, and this approach should be concentrated attention with the huge amount of expression data accumulating through the post-genome era.

  19. High Levels of Expression of P-glycoprotein/Multidrug Resistance Protein Result in Resistance to Vintafolide.

    PubMed

    Guertin, Amy D; O'Neil, Jennifer; Stoeck, Alexander; Reddy, Joseph A; Cristescu, Razvan; Haines, Brian B; Hinton, Marlene C; Dorton, Ryan; Bloomfield, Alicia; Nelson, Melissa; Vetzel, Marilynn; Lejnine, Serguei; Nebozhyn, Michael; Zhang, Theresa; Loboda, Andrey; Picard, Kristen L; Schmidt, Emmett V; Dussault, Isabelle; Leamon, Christopher P

    2016-08-01

    Targeting surface receptors overexpressed on cancer cells is one way to specifically treat cancer versus normal cells. Vintafolide (EC145), which consists of folate linked to a cytotoxic small molecule, desacetylvinblastine hydrazide (DAVLBH), takes advantage of the overexpression of folate receptor (FR) on cancer cells. Once bound to FR, vintafolide enters the cell by endocytosis, and the reducing environment of the endosome cleaves the linker, releasing DAVLBH to destabilize microtubules. Vintafolide has shown efficacy and improved tolerability compared with DAVLBH in FR-positive preclinical models. As the first FR-targeting drug to reach the clinic, vintafolide has achieved favorable responses in phase II clinical trials in FR-positive ovarian and lung cancer. However, some FR-positive patients in these clinical trials do not respond to vintafolide. We sought to identify potential biomarkers of resistance to aid in the future development of this and other FR-targeting drugs. Here, we confirm that high P-glycoprotein (P-gp) expression was the strongest predictor of resistance to DAVLBH in a panel of 359 cancer cell lines. Furthermore, targeted delivery of DAVLBH via the FR, as in vintafolide, fails to overcome P-gp-mediated efflux of DAVLBH in both in vitro and in vivo preclinical models. Therefore, we suggest that patients whose tumors express high levels of P-gp be excluded from future clinical trials for vintafolide as well as other FR-targeted therapeutics bearing a P-gp substrate. Mol Cancer Ther; 15(8); 1998-2008. ©2016 AACR. PMID:27256377

  20. Modulation of CYPs, P-gp, and PXR by Eschscholzia californica (California Poppy) and Its Alkaloids.

    PubMed

    Manda, Vamshi K; Ibrahim, Mohamed A; Dale, Olivia R; Kumarihamy, Mallika; Cutler, Stephen J; Khan, Ikhlas A; Walker, Larry A; Muhammad, Ilias; Khan, Shabana I

    2016-04-01

    Eschscholzia californica, a native US plant, is traditionally used as a sedative, analgesic, and anxiolytic herb. With the rapid rise in the use of herbal supplements together with over-the-counter and prescription drugs, the risk for potential herb-drug interactions is also increasing. Most of the clinically relevant pharmacokinetic drug interactions occur due to modulation of cytochrome P450 enzymes (CYPs), P-glycoprotein, and the pregnane X receptor by concomitantly used herbs. This study aimed to determine the effects of an EtOH extract, aqueous extract (tea), basic CHCl3 fractions, and isolated major alkaloids, namely protopine (1), escholtzine (2), allocryptopine (3), and californidine (4), of E. californica on the activity of cytochrome P450s, P-glycoprotein and the pregnane X receptor. The EtOH extract and fractions showed strong time-dependent inhibition of CYP 3A4, CYP 2C9, and CYP 2C19, and reversible inhibition of CYP 2D6. Among the alkaloids, escholtzine (2) and allocryptopine (3) exhibited time-dependent inhibition of CYP 3A4, CYP 2C9, and CYP 2C19 (IC50 shift ratio > 2), while protopine (1) and allocryptopine (3) showed reversible inhibition of CYP 2D6 enzyme. A significant activation of the pregnane X receptor (> 2-fold) was observed with the EtOH extract, basic CHCl3 fraction, and alkaloids (except protopine), which resulted into an increased expression of mRNA and the activity of CYP 3A4 and CYP 1A2. The expression of P-glycoprotein was unaffected. However, aqueous extract (tea) and its main alkaloid californidine (4) did not affect cytochrome P450s, P-glycoprotein, or the pregnane X receptor. This data suggests that EtOH extract of E. californica and its major alkaloids have a potential of causing interactions with drugs that are metabolized by cytochrome P450s, while the tea seems to be safer. PMID:27054913

  1. Predictable tuning of protein expression in bacteria.

    PubMed

    Bonde, Mads T; Pedersen, Margit; Klausen, Michael S; Jensen, Sheila I; Wulff, Tune; Harrison, Scott; Nielsen, Alex T; Herrgård, Markus J; Sommer, Morten O A

    2016-03-01

    We comprehensively assessed the contribution of the Shine-Dalgarno sequence to protein expression and used the data to develop EMOPEC (Empirical Model and Oligos for Protein Expression Changes; http://emopec.biosustain.dtu.dk). EMOPEC is a free tool that makes it possible to modulate the expression level of any Escherichia coli gene by changing only a few bases. Measured protein levels for 91% of our designed sequences were within twofold of the desired target level. PMID:26752768

  2. Synthesis of methylated quercetin derivatives and their reversal activities on P-gp- and BCRP-mediated multidrug resistance tumour cells.

    PubMed

    Yuan, Jian; Wong, Iris L K; Jiang, Tao; Wang, Si Wen; Liu, Tao; Wen, Bin Jin; Chow, Larry M C; Wan Sheng, Biao

    2012-08-01

    Three methylated quercetins and a series of O-3 substituted 5,7,3',4'-tetra-O-methylated quercetin derivatives have been synthesized and evaluated on the modulating activity of P-gp, BCRP and MRP1 in cancer cell lines. Compound 17 (with a 2-((4-methoxybenzoyl)oxy)ethyl at O-3) is the most potent P-gp modulator. Three derivatives, compound 9 (3,7,3',4'-tetra-O-methylated quercetin), compound 14 (with a 2-((3-oxo-3-(3,4,5trimethoxyphenyl)prop-1-en-1-yl)oxy)ethyl at O-3) and compound 17, consistently exhibited promising BCRP-modulating activity. Interestingly, compound 17 was found to be equipotent against both P-gp and BCRP. Importantly, these synthetic quercetin derivatives did not exhibit any inherent cytotoxicity to cancer cell lines or normal mouse fibroblast cell lines. These quercetin derivatives can be employed as safe and effective modulators of P-gp- or BCRP-mediated drug resistance in cancer. PMID:22743241

  3. Overcoming multidrug resistance in Dox-resistant neuroblastoma cell lines via treatment with HPMA copolymer conjugates containing anthracyclines and P-gp inhibitors.

    PubMed

    Koziolová, Eva; Janoušková, Olga; Cuchalová, Lucie; Hvězdová, Zuzana; Hraběta, Jan; Eckschlager, Tomáš; Sivák, Ladislav; Ulbrich, Karel; Etrych, Tomáš; Šubr, Vladimír

    2016-07-10

    Water-soluble N-(2-hydroxypropyl)methacrylamide copolymer conjugates bearing the anticancer drugs doxorubicin (Dox) or pirarubicin (THP), P-gp inhibitors derived from reversin 121 (REV) or ritonavir (RIT)), or both anticancer drug and P-gp inhibitor were designed and synthesized. All biologically active molecules were attached to the polymer carrier via pH-sensitive spacer enabling controlled release in mild acidic environment modeling endosomes and lysosomes of tumor cells. The cytotoxicity of the conjugates against three sensitive and Dox-resistant neuroblastoma (NB) cell lines, applied alone or in combination, was studied in vitro. All conjugates containing THP displayed higher cytotoxicity against all three Dox-resistant NB cell lines compared with the corresponding Dox-containing conjugates. Furthermore, the cytotoxicity of conjugates containing both drug and P-gp inhibitor was up to 10 times higher than that of the conjugate containing only drug. In general, the polymer-drug conjugates showed higher cytotoxicity when conjugates containing inhibitors were added 8 or 16h prior to treatment compared with conjugates bearing both the inhibitor and the drug. The difference in cytotoxicity was more pronounced at the 16-h time point. Moreover, higher inhibitor:drug ratios resulted in higher cytotoxicity. The cytotoxicity of the polymer-drug used in combination with polymer P-gp inhibitor was up to 84 times higher than that of the polymer-drug alone. PMID:27189135

  4. Expression of multiple proteins in transgenic plants

    DOEpatents

    Vierstra, Richard D.; Walker, Joseph M.

    2002-01-01

    A method is disclosed for the production of multiple proteins in transgenic plants. A DNA construct for introduction into plants includes a provision to express a fusion protein of two proteins of interest joined by a linking domain including plant ubiquitin. When the fusion protein is produced in the cells of a transgenic plant transformed with the DNA construction, native enzymes present in plant cells cleave the fusion protein to release both proteins of interest into the cells of the transgenic plant. Since the proteins are produced from the same fusion protein, the initial quantities of the proteins in the cells of the plant are approximately equal.

  5. P-gp, MRP2 and OAT1/OAT3 mediate the drug-drug interaction between resveratrol and methotrexate.

    PubMed

    Jia, Yongming; Liu, Zhihao; Wang, Changyuan; Meng, Qiang; Huo, Xiaokui; Liu, Qi; Sun, Huijun; Sun, Pengyuan; Yang, Xiaobo; Ma, Xiaodong; Liu, Kexin

    2016-09-01

    The purpose of present study was to investigate the effect of resveratrol (Res) on altering methotrexate (MTX) pharmacokinetics and clarify the related molecular mechanism. Res significantly increased rat intestinal absorption of MTX in vivo and in vitro. Simultaneously, Res inhibited MTX efflux transport in MDR1-MDCK and MRP2-MDCK cell monolayers, suggesting that the target of drug interaction was MDR1 and MRP2 in the intestine during the absorption process. Furthermore, there was a significant decrease in renal clearance of MTX after simultaneous intravenous administration. Similarly, MTX uptake was markedly inhibited by Res in rat kidney slices and hOAT1/3-HEK293 cell, indicating that OAT1 and OAT3 were involved in the drug interaction in the kidney. Additionally, concomitant administration of Res decreased cytotoxic effects of MTX in hOAT1/3-HEK293 cells, and ameliorated nephrotoxicity caused by MTX in rats. Conversely, intestinal damage caused by MTX was not exacerbated after Res treatment. In conclusion, Res enhanced MTX absorption in intestine and decreased MTX renal elimination by inhibiting P-gp, MRP2, OAT1 and OAT3 in vivo and in vitro. Res improved MTX-induced renal damage without increasing intestinal toxicity. PMID:27377006

  6. Expression and purification of GST fusion proteins.

    PubMed

    Harper, S; Speicher, D W

    2001-05-01

    An increasingly common strategy for expressing proteins and large peptides in prokaryotic systems is to express the protein of interest connected to a "tag" that provides the basis for rapid high-affinity purification. This unit describes the expression and purification of fusion proteins containing the 26-kDa glutathione-S-transferase protein as well as methods for cleaving the affinity tag and repurifying the target protein. Advantages of this popular fusion protein system include high protein yields, high-affinity one-step protein purification of the fusion protein, existence of several alternative protease cleavage sites for removing the affinity tag when required, and ease of removal of the cleaved affinity tag. PMID:18429193

  7. Comb-like amphiphilic polypeptide-based copolymer nanomicelles for co-delivery of doxorubicin and P-gp siRNA into MCF-7 cells.

    PubMed

    Suo, Aili; Qian, Junmin; Zhang, Yaping; Liu, Rongrong; Xu, Weijun; Wang, Hejing

    2016-05-01

    A comb-like amphiphilic copolymer methoxypolyethylene glycol-graft-poly(L-lysine)-block-poly(L-phenylalanine) (mPEG-g-PLL-b-Phe) was successfully synthesized. To synthesize mPEG-g-PLL-b-Phe, diblock copolymer PLL-b-Phe was first synthesized by successive ring-opening polymerization of α-amino acid N-carboxyanhydrides followed by the removal of benzyloxycarbonyl protecting groups, and then mPEG was grafted onto PLL-b-Phe by reductive amination via Schiff's base formation. The chemical structures of the copolymers were identified by (1)H NMR. mPEG-g-PLL-b-Phe copolymer had a critical micelle concentration of 6.0mg/L and could self-assemble in an aqueous solution into multicompartment nanomicelles with a mean diameter of approximately 78 nm. The nanomicelles could encapsulate doxorubicin (DOX) through hydrophobic and π-π stacking interactions between DOX molecules and Phe blocks and simultaneously complex P-gp siRNA with cationic PLL blocks via electrostatic interactions. The DOX/P-gp siRNA-loaded nanomicelles showed spherical morphology, possessed narrow particle size distribution and had a mean particle size of 120 nm. The DOX/P-gp siRNA-loaded nanomicelles exhibited pH-responsive release behaviors and displayed accelerated release under acidic conditions. The DOX/P-gp siRNA-loaded nanomicelles were efficiently internalized into MCF-7 cells, and DOX released could successfully reach nuclei. In vitro cytotoxicity assay demonstrated that the DOX/P-gp siRNA-loaded nanomicelles showed a much higher cytotoxicity in MCF-7 cells than DOX-loaded nanomicelles due to their synergistic killing effect and that the blank nanomicelles had good biocompatibility. Thus, the novel comb-like mPEG-g-PLL-b-Phe nanomicelles could be a promising vehicle for co-delivery of chemotherapeutic drug and genetic material. PMID:26952460

  8. Coevolution of gene expression among interacting proteins

    SciTech Connect

    Fraser, Hunter B.; Hirsh, Aaron E.; Wall, Dennis P.; Eisen,Michael B.

    2004-03-01

    Physically interacting proteins or parts of proteins are expected to evolve in a coordinated manner that preserves proper interactions. Such coevolution at the amino acid-sequence level is well documented and has been used to predict interacting proteins, domains, and amino acids. Interacting proteins are also often precisely coexpressed with one another, presumably to maintain proper stoichiometry among interacting components. Here, we show that the expression levels of physically interacting proteins coevolve. We estimate average expression levels of genes from four closely related fungi of the genus Saccharomyces using the codon adaptation index and show that expression levels of interacting proteins exhibit coordinated changes in these different species. We find that this coevolution of expression is a more powerful predictor of physical interaction than is coevolution of amino acid sequence. These results demonstrate previously uncharacterized coevolution of gene expression, adding a different dimension to the study of the coevolution of interacting proteins and underscoring the importance of maintaining coexpression of interacting proteins over evolutionary time. Our results also suggest that expression coevolution can be used for computational prediction of protein protein interactions.

  9. IF7-Conjugated Nanoparticles Target Annexin 1 of Tumor Vasculature against P-gp Mediated Multidrug Resistance.

    PubMed

    Yu, De-Hong; Liu, Ya-Rong; Luan, Xin; Liu, Hai-Jun; Gao, Yun-Ge; Wu, Hao; Fang, Chao; Chen, Hong-Zhuan

    2015-08-19

    Multidrug resistance is the main cause of clinical chemotherapeutic failure. Antiangiogenic cancer therapy with nanomedicine that allows the targeted delivery of antiangiogenic agents to tumor endothelial cells may contribute to innovative strategies for treating multidrug-resistant cancers. In this study, we developed a new nanodrug delivery system (nano-DDS), with improved antiangiogenic efficacy against multidrug resistant human breast cancer MCF-7/ADR cells. Here, the IF7 ligand was a peptide designed to bind the annexin 1 (Anxa 1), a highly specific marker of the tumor vasculature surface, with high affinity and specificity. IF7-conjugated Anxa 1-targeting nanoparticles containing paclitaxel (IF7-PTX-NP) allowed controlled drug release and displayed favorable prolonged circulation in vivo. IF7-PTX-NP was significantly internalized by human umbilical vein endothelial cells (HUVEC) through the IF7-Anxa 1 interaction, and this facilitated uptake enhanced the expected antiangiogenic activity of inhibiting HUVEC proliferation, migration, and tube formation in a Matrigel plug relative to those of Taxol and PTX-NP. As IF7-PTX-NP targeted the tumor vessels, more nanoparticles accumulated in MCF-7/ADR tumors, and more importantly, induced significant apoptosis of the tumor vascular endothelial cells and necrosis of the tumor tissues. Low dose paclitaxel (1 mg/kg) formulated in IF7-PTX-NP showed significant anticancer efficacy, delaying the growth of MCF-7/ADR tumors. The same efficacy was only obtained with an 8-fold dose of paclitaxel (8 mg/kg) as Taxol plus XR9576, a potent P-gp inhibitor. The anticancer efficacy of IF7-PTX-NP was strongly associated with the improved antiangiogenic effect, evident as a dramatic reduction in the tumor microvessel density and pronounced increase in apoptotic tumor cells, with no obvious toxicity to the mice. This nano-DDS, which targets the tumor neovasculature, offers a promising strategy for the treatment of multidrug

  10. An isoquinoline alkaloid from the Chinese herbal plant Corydalis yanhusuo W.T. Wang inhibits P-glycoprotein and multidrug resistance-associate protein 1.

    PubMed

    Lei, Yu; Tan, Juan; Wink, Michael; Ma, Yonggang; Li, Na; Su, Guannan

    2013-02-15

    Overexpression of P-glycoprotein (P-gp) and multidrug resistance-associate protein 1 (MRP1) is a major mechanism leading to multidrug resistance (MDR) of cancer cells. These transporters expel anti-cancer drugs and greatly impair therapeutic efficacy of chemotherapy. A Chinese herbal plant Yanhusuo (Corydalis yanhusuo W.T. Wang, YHS) is frequently used in functional food and traditional Chinese medicine to improve the efficacy of chemotherapy. The objective of this work was to study effects of glaucine, an alkaloid component of YHS, on P-gp and MRP1 in resistant cancer cells. The resistant cancer cell line, MCF-7/ADR and corresponding parental sensitive cells were employed to determine reversal properties of glaucine. Glaucine inhibits P-gp and MRP1-mediated efflux and activates ATPase activities of the transporters, indicating that it is a substrate and inhibits P-gp and MRP1 competitively. Furthermore, glaucine suppresses expression of ABC transporter genes. It reverses the resistance of MCF-7/ADR to adriamycin and mitoxantrone effectively. PMID:23194502

  11. Synergistic effect of folate-mediated targeting and verapamil-mediated P-gp inhibition with paclitaxel -polymer micelles to overcome multi-drug resistance.

    PubMed

    Wang, Feihu; Zhang, Dianrui; Zhang, Qiang; Chen, Yuxuan; Zheng, Dandan; Hao, Leilei; Duan, Cunxian; Jia, Lejiao; Liu, Guangpu; Liu, Yue

    2011-12-01

    Multidrug resistance (MDR) in tumor cells is a significant obstacle for successful cancer chemotherapy. Overexpression of drug efflux transporters such as P-glycoprotein (P-gp) is a key factor contributing to the development of tumor drug resistance. Verapamil (VRP), a P-gp inhibitor, has been reported to be able to reverse completely the resistance caused by P-gp. For optimal synergy, the drug and inhibitor combination may need to be temporally colocalized in the tumor cells. Herein, we investigated the effectiveness of simultaneous and targeted delivery of anticancer drug, paclitaxel (PTX), along with VRP, using DOMC-FA micelles to overcome tumor drug resistance. The floate-functionalized dual agent loaded micelles resulted in the similar cytotoxicity to PTX-loaded micelles/free VRP combination and co-administration of two single-agent loaded micelles, which was higher than that of PTX-loaded micelles. Enhanced therapeutic efficacy of dual agent micelles could be ascribe to increased accumulation of PTX in drug-resistant tumor cells. We suggest that the synergistic effect of folate receptor-mediated internalization and VRP-mediated overcoming MDR could be beneficial in treatment of MDR solid tumors by targeting delivery of micellar PTX into tumor cells. As a result, the difunctional micelle systems is a very promising approach to overcome tumor drug resistance. PMID:21903258

  12. Tissue-specific regulation of expression and activity of P-glycoprotein in adjuvant arthritis rats.

    PubMed

    Achira, Meguru; Totsuka, Ryuichi; Fujimura, Hisako; Kume, Toshiyuki

    2002-07-01

    Cyclosporine A and steroids are effective against rheumatoid arthritis and also known as substrates of P-glycoprotein (P-gp). We investigated the effect of arthritis on the hepatic and intestinal P-gp activity in rats, and substantiated the expression level of the hepatic P-gp. Doxorubicin was used as a P-gp substrate. Cumulative biliary excretion and intestinal exsorption of doxorubicin following intravenous administration were compared between adjuvant arthritis (AA) and normal rats. Intestinal P-gp activity was also investigated by intestinal everted sac method, and hepatic P-gp was detected by FITC-labeled antibody and visualized using a confocal laser microscope system. Biliary clearance of doxorubicin in AA rats was significantly decreased from that in normal rats. The expression level of the hepatic P-gp in AA rats was very low compared to normal rats, indicating down-regulation. Intestinal exsorption clearance was not different between AA and normal rats. Permeability of doxorubicin across intestinal everted sac was comparable between AA and normal rats, corresponding to in vivo study. In AA rats, hepatic P-gp activity was decreased due to the reduction of expression level, but intestinal P-gp activity was not changed. Different regulation systems may be involved in liver and intestine. PMID:12113888

  13. Human-Mouse Chimeras with Normal Expression and Function Reveal That Major Domain Swapping Is Tolerated by P-Glycoprotein (ABCB1).

    PubMed

    Pluchino, Kristen M; Hall, Matthew D; Moen, Janna K; Chufan, Eduardo E; Fetsch, Patricia A; Shukla, Suneet; Gill, Deborah R; Hyde, Stephen C; Xia, Di; Ambudkar, Suresh V; Gottesman, Michael M

    2016-02-23

    The efflux transporter P-glycoprotein (P-gp) plays a vital role in the transport of molecules across cell membranes and has been shown to interact with a panoply of functionally and structurally unrelated compounds. How human P-gp interacts with this large number of drugs has not been well understood, although structural flexibility has been implicated. To gain insight into this transporter's broad substrate specificity and to assess its ability to accommodate a variety of molecular and structural changes, we generated human-mouse P-gp chimeras by the exchange of homologous transmembrane and nucleotide-binding domains. High-level expression of these chimeras by BacMam- and baculovirus-mediated transduction in mammalian (HeLa) and insect cells, respectively, was achieved. There were no detectable differences between wild-type and chimeric P-gp in terms of cell surface expression, ability to efflux the P-gp substrates rhodamine 123, calcein-AM, and JC-1, or to be inhibited by the substrate cyclosporine A and the inhibitors tariquidar and elacridar. Additionally, expression of chimeric P-gp was able to confer a paclitaxel-resistant phenotype to HeLa cells characteristic of P-gp-mediated drug resistance. P-gp ATPase assays and photo-cross-linking with [(125)I]iodoarylazidoprazosin confirmed that transport and biochemical properties of P-gp chimeras were similar to those of wild-type P-gp, although differences in drug binding were detected when human and mouse transmembrane domains were combined. Overall, chimeras with one or two mouse P-gp domains were deemed functionally equivalent to human wild-type P-gp, demonstrating the ability of human P-gp to tolerate major structural changes. PMID:26820614

  14. Low Intensity Ultrasound Promotes the Sensitivity of Rat Brain Glioma to Doxorubicin by Down-Regulating the Expressions of P-Glucoprotein and Multidrug Resistance Protein 1 In Vitro and In Vivo

    PubMed Central

    Zhang, Zhen; Xu, Ke; Bi, Yonghua; Yu, Guibo; Wang, Siwei; Qi, Xun; Zhong, Hongshan

    2013-01-01

    The overall prognosis for malignant glioma is extremely poor, and treatment options are limited in part because of multidrug resistant proteins. Our previous findings suggest low intensity ultrasound (LIUS) can induce apoptosis of glioma cells. Given this finding, we were interested in determining if LIUS could help treat glioma by inhibiting multidrug resistant proteins, and if so, which pathways are involved. In this study, the toxicity sensitivity and multidrug resistance proteins of glioma induced by LIUS were investigated using CCK-8, immunohistochemistry, immunofluorency, and RT-PCR in tissue samples and cultured cells. LIUS inhibited increase of C6 cells in an intensity- and time-dependent manner. The toxicity sensitivity of C6 cells increased significantly after LIUS sonication (intensity of 142.0 mW/cm2) or Doxorubicin (DOX) at different concentration, particularly by the combination of LIUS sonication and DOX. The expressions of P-gp and MRP1 decreased significantly post-sonication at intensity of 142.0 mW/cm2 both in vitro and in vivo. The expressions of p110 delta (PI3K), NF-κB-p65, Akt/PKB, and p-Akt/PKB were downregulated by LIUS sonication and DOX treatment separately or in combination at the same parameters in rat glioma. These results indicate that LIUS could increase the toxicity sensitivity of glioma by down-regulating the expressions of P-gp and MRP1, which might be mediated by the PI3K/Akt/NF-κB pathway. PMID:23940624

  15. Alterations in function and expression of ABC transporters at blood-brain barrier under diabetes and the clinical significances

    PubMed Central

    Liu, Li; Liu, Xiao-Dong

    2014-01-01

    Diabetes is a systematic metabolic disease, which often develops a number of well-recognized vascular complications including brain complications which may partly result from the dysfunction of blood-brain barrier (BBB). BBB is generally considered as a mechanism for protecting the brain from unwanted actions resulting from substances in the blood and maintaining brain homeostasis via monitoring the entry or efflux of compounds. ATP-binding cassette (ABC) family of transporters including P-glycoprotein (P-GP) and breast cancer-related protein (BCRP), widely expressed in the luminal membrane of the microvessel endothelium and in the apical membrane of the choroids plexus epithelium, play important roles in the function of BBB. However, these transporters are easily altered by some diseases. The present article was focused on the alteration in expression and function of both P-GP and BCRP at BBB by diabetes and the clinical significances. PMID:25540622

  16. Transient Protein Expression by Agroinfiltration in Lettuce.

    PubMed

    Chen, Qiang; Dent, Matthew; Hurtado, Jonathan; Stahnke, Jake; McNulty, Alyssa; Leuzinger, Kahlin; Lai, Huafang

    2016-01-01

    Current systems of recombinant protein production include bacterial, insect, and mammalian cell culture. However, these platforms are expensive to build and operate at commercial scales and/or have limited abilities to produce complex proteins. In recent years, plant-based expression systems have become top candidates for the production of recombinant proteins as they are highly scalable, robust, safe, and can produce complex proteins due to having a eukaryotic endomembrane system. Newly developed "deconstructed" viral vectors delivered via Agrobacterium tumefaciens (agroinfiltration) have enabled robust plant-based production of proteins with a wide range of applications. The leafy Lactuca sativa (lettuce) plant with its strong foundation in agriculture is an excellent host for pharmaceutical protein production. Here, we describe a method for agroinfiltration of lettuce that can rapidly produce high levels of recombinant proteins in a matter of days and has the potential to be scaled up to an agricultural level. PMID:26614281

  17. Biotechnology Protein Expression and Purification Facility

    NASA Technical Reports Server (NTRS)

    2003-01-01

    The purpose of the Project Scientist Core Facility is to provide purified proteins, both recombinant and natural, to the Biotechnology Science Team Project Scientists and the NRA-Structural Biology Test Investigators. Having a core facility for this purpose obviates the need for each scientist to develop the necessary expertise and equipment for molecular biology, protein expression, and protein purification. Because of this, they are able to focus their energies as well as their funding on the crystallization and structure determination of their target proteins.

  18. Membrane protein expression in Lactococcus lactis.

    PubMed

    King, Martin S; Boes, Christoph; Kunji, Edmund R S

    2015-01-01

    The Gram-positive bacterium Lactococcus lactis has many properties that are ideal for the overproduction of membrane proteins in a functional form. Growth of lactococci is rapid, proceeds to high cell densities, and does not require aeration, which facilitates large-scale fermentation. The available promoter systems are strong and tightly regulated, allowing expression of toxic gene products in a controlled manner. Expressed membrane proteins are targeted exclusively to the cytoplasmic membrane, allowing the use of ionophores, ligands, and inhibitors to study activity of the membrane protein in whole cells. Constructed plasmids are stable and expression levels are highly reproducible. The relatively small genome size of the organism causes little redundancy, which facilitates complementation studies and allows for easier purification. The produced membrane proteins are often stable, as the organism has limited proteolytic capability, and they are readily solubilized from the membrane with mild detergents. Lactococci are multiple amino acid auxotrophs, allowing the incorporation of labels, such as selenomethionine. Among the few disadvantages are the low transformation frequency, AT-rich codon usage, and resistance to lysis by mechanical means, but these problems can be overcome fairly easily. We will describe in detail the protocols used to express membrane proteins in L. lactis, from cloning of the target gene to the isolation of membrane vesicles for the determination of expression levels. PMID:25857778

  19. Proteomics for Protein Expression Profiling in Neuroscience*

    PubMed Central

    Freeman, Willard M.; Hemby, Scott E.

    2013-01-01

    As the technology of proteomics moves from a theoretical approach to a practical reality, neuroscientists will have to determine the most appropriate applications for this technology. Neuroscientists will have to surmount difficulties particular to their research, such as limited sample amounts, heterogeneous cellular compositions in samples, and the fact that many proteins of interest are rare, hydrophobic proteins. This review examines protein isolation and protein fractionation and separation using two-dimensional electrophoresis (2-DE) and mass spectrometry proteomic methods. Methods for quantifying relative protein expression between samples (e.g., 2-DIGE, and ICAT) are also described. The coverage of the proteome, ability to detect membrane proteins, resource requirements, and quantitative reliability of different approaches is also discussed. Although there are many challenges in proteomic neuroscience, this field promises many rewards in the future. PMID:15176464

  20. Inhibition of P-glycoprotein expression and function by anti-diabetic drugs gliclazide, metformin, and pioglitazone in vitro and in situ

    PubMed Central

    Abbasi, Mehran Mesgari; Valizadeh, Hadi; Hamishehkar, Hamed; Zakeri-Milani, Parvin

    2016-01-01

    P-glycoprotein (P-gp) is a trans-membrane drug efflux pump. Several drugs are P-gp substrates. Some drugs may affect the activity of P-gp by inhibiting its function, resulting in significant drug-drug interactions (DDIs). It is critical to understand which drugs are inhibitors of P-gp so that adverse DDIs can be minimized or avoided. This study investigated the effects of gliclazide, metformin, and pioglitazone on the function and expression of P-gp. Rhodamine 123 (Rh 123) efflux assays in Caco-2 cells and western blot testing were used to study in vitro the effect of the drugs on P-gp function and expression. The in situ rat single-pass intestinal permeability model was developed to study the effect of the drugs on P-gp function. Digoxin and verapamil were used as a known substrate and inhibitor of P-gp, respectively. Digoxin levels in intestinal perfusion samples were analyzed by high-performance liquid chromatography. Intestinal effective permeability (Peff) of digoxin in the presence of 0.1, 10, and 500 μM gliclazide, 100 and 7000 μM metformin, and 50 and 300 μM pioglitazone was significantly increased relative to the digoxin treated cells (P < 0.01). P-gp expression was decreased by gliclazide, metformin and pioglitazone. Intracellular accumulation of Rh 123 by the drugs increased, but the differences were not significant relative to the control cells (P > 0.05). It was found that gliclazide, metformin, and pioglitazone inhibited P-gp efflux activity in situ and down-regulated P-gp expression in vitro. Further investigations are necessary to confirm the obtained results and to define the mechanism underlying P-gp inhibition by the drugs. PMID:27499787

  1. Inhibition of P-glycoprotein expression and function by anti-diabetic drugs gliclazide, metformin, and pioglitazone in vitro and in situ.

    PubMed

    Abbasi, Mehran Mesgari; Valizadeh, Hadi; Hamishehkar, Hamed; Zakeri-Milani, Parvin

    2016-01-01

    P-glycoprotein (P-gp) is a trans-membrane drug efflux pump. Several drugs are P-gp substrates. Some drugs may affect the activity of P-gp by inhibiting its function, resulting in significant drug-drug interactions (DDIs). It is critical to understand which drugs are inhibitors of P-gp so that adverse DDIs can be minimized or avoided. This study investigated the effects of gliclazide, metformin, and pioglitazone on the function and expression of P-gp. Rhodamine 123 (Rh 123) efflux assays in Caco-2 cells and western blot testing were used to study in vitro the effect of the drugs on P-gp function and expression. The in situ rat single-pass intestinal permeability model was developed to study the effect of the drugs on P-gp function. Digoxin and verapamil were used as a known substrate and inhibitor of P-gp, respectively. Digoxin levels in intestinal perfusion samples were analyzed by high-performance liquid chromatography. Intestinal effective permeability (Peff) of digoxin in the presence of 0.1, 10, and 500 μM gliclazide, 100 and 7000 μM metformin, and 50 and 300 μM pioglitazone was significantly increased relative to the digoxin treated cells (P < 0.01). P-gp expression was decreased by gliclazide, metformin and pioglitazone. Intracellular accumulation of Rh 123 by the drugs increased, but the differences were not significant relative to the control cells (P > 0.05). It was found that gliclazide, metformin, and pioglitazone inhibited P-gp efflux activity in situ and down-regulated P-gp expression in vitro. Further investigations are necessary to confirm the obtained results and to define the mechanism underlying P-gp inhibition by the drugs. PMID:27499787

  2. Enhanced expression of adenovirus transforming proteins.

    PubMed Central

    Gaynor, R B; Tsukamoto, A; Montell, C; Berk, A J

    1982-01-01

    Proteins encoded in regions EIA and EIB of human adenoviruses cause transformation of rodent cells. One protein from EIA also stimulates transcription of other early regions at early times in a productive infection. In the past, direct analysis of these proteins synthesized in vivo has been difficult because of the low levels produced in both transformed cells and productively infected cells. We present a simple method which leads to expression of EIA and EIB mRNAs and proteins at 30-fold greater levels than those observed during the early phase of a standard productive infection. Under these conditions, these proteins are among the most prominent translation products of infected cells. This allowed direct visualization of EIA and EIB proteins on two-dimensional gels of pulse-labeled total cell protein. Experiments with EIA and EIB mutants confirm that the identified proteins are indeed encoded in these regions. Two EIA proteins are observed, one translated from each of the major early EIA mRNAs. Both of these EIA proteins are phosphorylated. Images PMID:7143568

  3. The potential predictive role of nuclear NHERF1 expression in advanced gastric cancer patients treated with epirubicin/oxaliplatin/capecitabine first line chemotherapy.

    PubMed

    Mangia, Anita; Caldarola, Lucia; Dell'Endice, Stefania; Scarpi, Emanuela; Saragoni, Luca; Monti, Manlio; Santini, Daniele; Brunetti, Oronzo; Simone, Giovanni; Silvestris, Nicola

    2015-01-01

    Cellular resistance in advanced gastric cancer (GC) might be related to function of multidrug resistance (MDR) proteins. The adaptor protein NHERF1 (Na(+)/H(+) exchanger regulatory factor) is an important player in cancer progression for a number of solid malignancies, even if its role to develop drug resistance remains uncertain. Herein, we aimed to analyze the potential association between NHERF1 expression and P-gp, sorcin and HIF-1α MDR-related proteins in advanced GC patients treated with epirubicin/oxaliplatin/capecitabine (EOX) chemotherapy regimen, and its relation to response. Total number of 28 untreated patients were included into the study. Expression and subcellular localization of all proteins were assessed by immunohistochemistry on formalin-fixed paraffin embedded tumor samples. We did not found significant association between NHERF1 expression and the MDR-related proteins. A trend was observed between positive cytoplasmic NHERF1 (cNHERF1) expression and negative nuclear HIF-1α (nHIF-1α) expression (68.8% versus 31.3% respectively, P = 0.054). However, cytoplasmic P-gp (cP-gp) expression was positively correlated with both cHIF-1α and sorcin expression (P = 0.011; P = 0.002, respectively). Interestingly, nuclear NHERF1 (nNHERF1) staining was statistically associated with clinical response. In detail, 66.7% of patients with high nNHERF1 expression had a disease control rate, while 84.6% of subjects with negative nuclear expression of the protein showed progressive disease (P = 0.009). Multivariate analysis confirmed a significant correlation between nNHERF1 and clinical response (OR 0.06, P = 0.019). These results suggest that nuclear NHERF1 could be related to resistance to the EOX regimen in advanced GC patients, identifying this marker as a possible independent predictive factor. PMID:26126066

  4. The potential predictive role of nuclear NHERF1 expression in advanced gastric cancer patients treated with epirubicin/oxaliplatin/capecitabine first line chemotherapy

    PubMed Central

    Mangia, Anita; Caldarola, Lucia; Dell'Endice, Stefania; Scarpi, Emanuela; Saragoni, Luca; Monti, Manlio; Santini, Daniele; Brunetti, Oronzo; Simone, Giovanni; Silvestris, Nicola

    2015-01-01

    Cellular resistance in advanced gastric cancer (GC) might be related to function of multidrug resistance (MDR) proteins. The adaptor protein NHERF1 (Na+/H+ exchanger regulatory factor) is an important player in cancer progression for a number of solid malignancies, even if its role to develop drug resistance remains uncertain. Herein, we aimed to analyze the potential association between NHERF1 expression and P-gp, sorcin and HIF-1α MDR-related proteins in advanced GC patients treated with epirubicin/oxaliplatin/capecitabine (EOX) chemotherapy regimen, and its relation to response. Total number of 28 untreated patients were included into the study. Expression and subcellular localization of all proteins were assessed by immunohistochemistry on formalin-fixed paraffin embedded tumor samples. We did not found significant association between NHERF1 expression and the MDR-related proteins. A trend was observed between positive cytoplasmic NHERF1 (cNHERF1) expression and negative nuclear HIF-1α (nHIF-1α) expression (68.8% versus 31.3% respectively, P = 0.054). However, cytoplasmic P-gp (cP-gp) expression was positively correlated with both cHIF-1α and sorcin expression (P = 0.011; P = 0.002, respectively). Interestingly, nuclear NHERF1 (nNHERF1) staining was statistically associated with clinical response. In detail, 66.7% of patients with high nNHERF1 expression had a disease control rate, while 84.6% of subjects with negative nuclear expression of the protein showed progressive disease (P = 0.009). Multivariate analysis confirmed a significant correlation between nNHERF1 and clinical response (OR 0.06, P = 0.019). These results suggest that nuclear NHERF1 could be related to resistance to the EOX regimen in advanced GC patients, identifying this marker as a possible independent predictive factor. PMID:26126066

  5. Expression Pattern of Id Proteins in Medulloblastoma

    PubMed Central

    Snyder, Andrew D.; Dulin-Smith, Ashley N.; Houston, Ronald H.; Durban, Ashley N.; Brisbin, Bethany J.; Oostra, Tyler D.; Marshall, Jordan T.; Kahwash, Basil M.

    2013-01-01

    Inhibitor of DNA binding or inhibitor of differentiation (Id) proteins are up regulated in a variety of neoplasms, particularly in association with high-grade, poorly differentiated tumors, while differentiated tissues show little or no Id expression. The four Id genes are members of the helix-loop-helix (HLH) family of transcription factors and act as negative regulators of transcription by binding to and sequestering HLH complexes. We tested the hypothesis that Id proteins are overexpressed in medulloblastoma by performing immunohistochemistry using a medulloblastoma tissue microarray with 45 unique medulloblastoma and 11 normal control cerebella, and antibodies specific for Id1, Id2, Id3, and Id4. A semi-quantitative staining score that took staining intensity and the proportion of immunoreactive cells into account was used. Id1 was not detected in normal cerebella or in medulloblastoma cells, but 78 % of tumors showed strong Id1 expression in endothelial nuclei of tumor vessels. Id2 expression was scant in normal cerebella and increased in medulloblastoma (median staining score: 4). Id3 expression was noted in some neurons of the developing cerebellar cortex, but it was markedly up regulated in medulloblastoma (median staining score: 12) and in tumor endothelial cells. Id4 was not expressed in normal cerebella or in tumor cells. Id2 or Id3 overexpression drove proliferation in medulloblastoma cell lines by altering the expression of critical cell cycle regulatory proteins in favor of cell proliferation. This study shows that Id1 expression in endothelial cells may contribute to angiogenic processes and that increased expression of Id2 and Id3 in medulloblastoma is potentially involved in tumor cell proliferation and survival. PMID:23397264

  6. Cultured CD4T cells and primary human lymphocytes express hOATPs: intracellular accumulation of saquinavir and lopinavir

    PubMed Central

    Janneh, O; Hartkoorn, R C; Jones, E; Owen, A; Ward, S A; Davey, R; Back, D J; Khoo, S H

    2008-01-01

    Background and purpose: Drug efflux tranporters (P-glycoprotein (P-gp), multidrug resistance-associated protein (MRP)) limit the cellular uptake of human immunodeficiency virus protease inhibitors but the contribution of influx transporters in cells that (over)express P-gp or MRP is less clear. Here, we studied the expression of one influx transporter system, human organic anion-transporting polypeptide (hOATP), in some T-cell lines (CEM, CEMVBL, CEME1000) and in peripheral blood mononuclear cells (PBMCs) and examined the effects of manipulation of influx/efflux transporters on the uptake of saquinavir and lopinavir. Experimental approach: The expression of hOATPs was studied by PCR. We used hOATP substrate or inhibitor (estrone-3-sulphate (E-3-S) or montelukast, respectively) and inhibitors of P-gp (XR9576) and MRP (MK571 and frusemide) to study functional interactions between influx and efflux transporters in the uptake of saquinavir and lopinavir. Lipophilicity of the drugs was measured by octanol/saline partition coefficient. Key results: CEM cells, their variants and PBMCs express various hOATP isoforms, with OATP3A1 detected in all of the cells. MK571, XR9576 and frusemide increased the uptake of saquinavir and lopinavir. E-3-S and montelukast reduced the uptake of saquinavir and lopinavir in some, but not all, of the cells. Pretreatment of the cells with MK571, XR9576 or frusemide, followed by E-3-S co-incubation reduced the cellular accumulation of saquinavir and lopinavir. Lopinavir is much more lipophilic than saquinavir. Conclusions and implications: Human OATPs, MRP, P-gp and lipophilicity determine the cellular uptake and retention of saquinavir and lopinavir. These data may have important implications for drug–drug interactions, drug safety and efficacy. PMID:19002102

  7. Influence of Panax ginseng on cytochrome P450 (CYP)3A and P-glycoprotein (P-gp) activity in healthy participants.

    PubMed

    Malati, Christine Y; Robertson, Sarah M; Hunt, Jennifer D; Chairez, Cheryl; Alfaro, Raul M; Kovacs, Joseph A; Penzak, Scott R

    2012-06-01

    A number of herbal preparations have been shown to interact with prescription medications secondary to modulation of cytochrome P450 (CYP) and/or P-glycoprotein (P-gp). The purpose of this study was to determine the influence of Panax ginseng on CYP3A and P-gp function using the probe substrates midazolam and fexofenadine, respectively. Twelve healthy participants (8 men) completed this open-label, single-sequence pharmacokinetic study. Healthy volunteers received single oral doses of midazolam 8 mg and fexofenadine 120 mg, before and after 28 days of P ginseng 500 mg twice daily. Midazolam and fexofenadine pharmacokinetic parameter values were calculated and compared before and after P ginseng administration. Geometric mean ratios (postginseng/preginseng) for midazolam area under the concentration-time curve from zero to infinity (AUC(0-∞)), half-life (t(1/2)), and maximum concentration (C(max)) were significantly reduced at 0.66 (0.55-0.78), 0.71 (0.53-0.90), and 0.74 (0.56-0.93), respectively. Conversely, fexofenadine pharmacokinetics were unaltered by P ginseng administration. Based on these results, P ginseng appeared to induce CYP3A activity in the liver and possibly the gastrointestinal tract. Patients taking P ginseng in combination with CYP3A substrates with narrow therapeutic ranges should be monitored closely for adequate therapeutic response to the substrate medication. PMID:21646440

  8. Tumor endothelial expression of P-glycoprotein upon microvesicular transfer of TrpC5 derived from adriamycin-resistant breast cancer cells

    SciTech Connect

    Dong, YePing; Pan, QiongXi; Jiang, Li; Chen, Zhen; Zhang, FangFang; Liu, YanJun; Xing, Hui; Shi, Mei; Li, Jiao; Li, XiYuan; Zhu, YaoDan; Chen, Yun; Bruce, Iain C.; Jin, Jian Ma, Xin

    2014-03-28

    Highlights: • TrpC5 was mainly accumulated in microvesicles of drug-resistant MCF-7/ADM cells. • Microvesicles from MCF-7/ADM transferred TrpC5 to endothelial cells. • TrpC5 inhibition reduced P-glycoprotein accumulation on tumor blood vessels in vivo. - Abstract: Treatment of carcinoma commonly fails due to chemoresistance. Studies have shown that endothelial cells acquire resistance via the tumor microenvironment. Microvesicle (MV) shedding from the cell membrane to the microenvironment plays an important role in communication between cells. The aim of the present study was to determine whether MCF-7 adriamycin-resistant cells (MCF-7/ADM) shed MVs that alter the characteristics of human microvessel endothelial cells (HMECs). MVs from tumor cells transferred a Ca{sup 2+}-permeable channel TrpC5 to HMECs, inducing the expression of P-glycoprotein (P-gp) by activation of the transcription factor NFATc3 (nuclear factor of activated T cells isoform c3). Expression of the mdr1 gene was blocked by the TrpC5-blocking antibody T5E3, and the production of P-gp in HMECs was reduced by blockade of TrpC5. Thus, we postulate that endothelial cells acquire the resistant protein upon exposure to TrpC5-containg MVs in the microenvironment, and express P-gp in the TrpC5–NFATc3 signal pathway.

  9. Microgravity alters the expression of salivary proteins.

    PubMed

    Mednieks, Maija; Khatri, Aditi; Rubenstein, Renee; Burleson, Joseph A; Hand, Arthur R

    2014-06-01

    Spaceflight provides a unique opportunity to study how physiologic responses are influenced by the external environment. Microgravity has been shown to alter the function of a number of tissues and organ systems. Very little, however, is known about how microgravity affects the oral cavity. The rodent model is useful for study in that their salivary gland morphology and physiology is similar to that of humans. Useful also is the fact that saliva, a product of the salivary glands with a major role in maintaining oral health, can be easily collected in humans whereas the glands can be studied in experimental animals. Our working hypothesis is that expression of secretory proteins in saliva will respond to microgravity and will be indicative of the nature of physiologic reactions to travel in space. This study was designed to determine which components of the salivary proteome are altered in mice flown on the US space shuttle missions and to determine if a subset with predictive value can be identified using microscopy and biochemistry methods. The results showed that the expression of secretory proteins associated with beta-adrenergic hormone regulated responses and mediated via the cyclic AMP pathway was significantly altered, whereas that of a number of unrelated proteins was not. The findings are potentially applicable to designing a biochemical test system whereby specific salivary proteins can be biomarkers for stress associated with travel in space and eventually for monitoring responses to conditions on earth. PMID:24984624

  10. Quantitative Assessment of the Impact of Fluorine Substitution on P-Glycoprotein (P-gp) Mediated Efflux, Permeability, Lipophilicity, and Metabolic Stability.

    PubMed

    Pettersson, Martin; Hou, Xinjun; Kuhn, Max; Wager, Travis T; Kauffman, Gregory W; Verhoest, Patrick R

    2016-06-01

    Strategic replacement of one or more hydrogen atoms with fluorine atom(s) is a common tactic to improve potency at a given target and/or to modulate parameters such as metabolic stability and pKa. Molecular weight (MW) is a key parameter in design, and incorporation of fluorine is associated with a disproportionate increase in MW considering the van der Waals radius of fluorine versus hydrogen. Herein we examine a large compound data set to understand the effect of introducing fluorine on the risk of encountering P-glycoprotein mediated efflux (as measured by MDR efflux ratio), passive permeability, lipophilicity, and metabolic stability. Statistical modeling of the MDR ER data demonstrated that an increase in MW as a result of introducing fluorine atoms does not lead to higher risk of P-gp mediated efflux. Fluorine-corrected molecular weight (MWFC), where the molecular weight of fluorine has been subtracted, was found to be a more relevant descriptor. PMID:27228214

  11. Regulation of Mutant p53 Protein Expression

    PubMed Central

    Vijayakumaran, Reshma; Tan, Kah Hin; Miranda, Panimaya Jeffreena; Haupt, Sue; Haupt, Ygal

    2015-01-01

    For several decades, p53 has been detected in cancer biopsies by virtue of its high protein expression level which is considered indicative of mutation. Surprisingly, however, mouse genetic studies revealed that mutant p53 is inherently labile, similar to its wild type (wt) counterpart. Consistently, in response to stress conditions, both wt and mutant p53 accumulate in cells. While wt p53 returns to basal level following recovery from stress, mutant p53 remains stable. In part, this can be explained in mutant p53-expressing cells by the lack of an auto-regulatory loop with Mdm2 and other negative regulators, which are pivotal for wt p53 regulation. Further, additional protective mechanisms are acquired by mutant p53, largely mediated by the co-chaperones and their paralogs, the stress-induced heat shock proteins. Consequently, mutant p53 is accumulated in cancer cells in response to chronic stress and this accumulation is critical for its oncogenic gain of functions (GOF). Building on the extensive knowledge regarding wt p53, the regulation of mutant p53 is unraveling. In this review, we describe the current understanding on the major levels at which mutant p53 is regulated. These include the regulation of p53 protein levels by microRNA and by enzymes controlling p53 proteasomal degradation. PMID:26734569

  12. Expression of Contractile Protein Isoforms in Microgravity

    NASA Technical Reports Server (NTRS)

    Anderson, Page A. W.

    1996-01-01

    The general objective of this experiment is to determine the effect of space flight parameters, including microgravity, on ontogenesis and embryogenesis of Japanese quail. Nine U.S. and two Russian investigators are cooperating in this study. Specific objectives of the participating scientists include assessing the gross and microscopic morphological and histological development of the embryo, as well as the temporal and spacial development of specific cells, tissues, and organs. Temporally regulated production of specific proteins is also being investigated. Our objective is to determine the effects of microgravity on developmentally programmed expression of Troponin T and I isoforms known to regulate cardiac and skeletal muscle contraction.

  13. Expression, regulation, and function of drug transporters in cervicovaginal tissues of a mouse model used for microbicide testing.

    PubMed

    Zhou, Tian; Hu, Minlu; Pearlman, Andrew; Rohan, Lisa C

    2016-09-15

    P-glycoprotein (P-gp), breast cancer resistance protein (BCRP), and multidrug resistance protein 4 (MRP4) are three efflux transporters that play key roles in the pharmacokinetics of antiretroviral drugs used in the pre-exposure prophylaxis of HIV sexual transmission. In this study, we investigated the expression, regulation, and function of these transporters in cervicovaginal tissues of a mouse model. Expression and regulation were examined using real-time RT-PCR and immunohistochemical staining, in the mouse tissues harvested at estrus and diestrus stages under natural cycling or after hormone synchronization. The three transporters were expressed at moderate to high levels compared to the liver. Transporter proteins were localized in various cell types in different tissue segments. Estrous cycle and exogenous hormone treatment affected transporter mRNA and protein expression, in a tissue- and transporter-dependent manner. Depo-Provera-synchronized mice were dosed vaginally or intraperitoneally with (3)H-TFV, with or without MK571 co-administration, to delineate the function of cervicovaginal Mrp4. Co-administration of MK571 significantly increased the concentration of vaginally-administered TFV in endocervix and vagina. MK571 increased the concentration of intraperitoneally-administered TFV in the cervicovaginal lavage and vagina by several fold. Overall, P-gp, Bcrp, and Mrp4 were positively expressed in mouse cervicovaginal tissues, and their expression can be regulated by the estrous cycle or by exogenous hormones. In this model, the Mrp4 transporter impacted TFV distribution in cervicovaginal tissues. PMID:27453435

  14. Ecto-5′-nucleotidase expression is associated with the progression of renal cell carcinoma

    PubMed Central

    YU, YI; WANG, WEI; SONG, LEI; HU, WENTAO; DONG, CHI; PEI, HAILONG; ZHOU, GUANGMING; YUE, ZHONGJIN

    2015-01-01

    Renal cell carcinoma (RCC) is a common tissue tumor that occurs across all age groups and has become one of the types of cancer with the fastest increasing incidence. Due to the resistance of RCC chemo- and radiotherapy, surgery is the only currently effective treatment. Therefore, specific markers for the diagnosis and prognosis of RCC are expected to result in novel methods of treatment. Ecto-5′-nucleotidase, also termed cluster of differentiation (CD)73, is a protein that is activated in several types of aggressive cancer and may promote cancer progression. CD73 was examined in the present study to determine the association between the protein and RCC. The expression levels of CD73 in 159 RCC tissue sections and 30 paratumorous normal renal tissue samples obtained from 235 patients that underwent nephrectomy were examined by immunohistochemical staining. By contrast, the expression level of P-glycoprotein (P-gp), a potential prognostic factor in RCC, was also examined in 85 RCC and 13 normal tissue samples. Intense CD73 expression was identified in 75 out of 159 RCC cell membranes compared with normal renal tissues. In contrast, there was high P-gp expression in the blood vessels of 42 out of 85 RCC tissues and there was no significant difference between the P-gp expression identified in RCC cells (34 out of 85) and the cell membrane of normal renal cells (2 out of 13). The expression level of CD73 in RCC cells was significantly associated with tumor type, tumor node metastasis (TNM) stage, and tumor grade. However, the expression of P-gp in RCC cells was only associated with the TNM stage and tumor grade. Using a multivariable Cox regression analysis, it was found that the median survival rate of RCC patients with intense CD73 expression in RCC cells was 62.06±5.35 months, which was drastically shorter compared with rare CD73 expression (103.72±3.67 months). In conclusion, the expression level of CD73 is significantly associated with RCC tumor progression

  15. The Effects of Cetirizine on P-glycoprotein Expression and Function In vitro and In situ

    PubMed Central

    Mesgari Abbasi, Mehran; Valizadeh, Hadi; Hamishekar, Hamed; Mohammadnejad, Leila; Zakeri-Milani, Parvin

    2016-01-01

    Purpose: P-glycoprotein (P-gp) plays a major role in oral absorption of drugs. Induction or inhibition of P-gp by drugs contributes to variability of its transport activity and often results in clinically relevant drug-drug interactions. The purpose of this study was to investigate the effect of cetirizine, a second generation H1 antihistamine, on P-gp function and expression in vitro and in situ. Methods: The in-vitro rhodamin-123 (Rho123) efflux assay in Caco-2 cells was used to study the effect of cetirizine on P-gp function. Western blot analysis was used for surveying the effect of cetirizine on expression of P-gp in Caco-2 cells. Rat in situ single-pass intestinal permeability technique was used to calculate the intestinal permeability of a known P-gp substrate (digoxin) in the presence of cetirizine. The amounts of digoxin and cetirizine in intestinal perfusion samples were analyzed using a HPLC method. Results: The results showed significant increase in Rho123 uptake (P < 0.05) and also P-gp band intensity decrease in cetirizine-treated cells in vitro. Furthermore the intestinal permeability of digoxin was also increased significantly in the presence of cetirizine (P < 0.01). Conclusion: Therefore it is concluded that cetirizine is a P-gp inhibitor and this should be considered in co administration of cetrizine with other P-gp substrate drugs. Further investigations are required to confirm our results and to determine the mechanism underlying P-gp inhibition by cetirizine. PMID:27123426

  16. Arabidopsis thaliana SEPALLATA3 protein prokaryotic expression and purification.

    PubMed

    He, Q; Fu, A Y; Zhang, G C; Li, T J; Zhang, J H

    2015-01-01

    SEPALLATA3 (SEP3) can be attributed to E class gene of the ABCE model of floral organ development. In order to reveal how SEP3 proteins form polymers, and the relationship between the polymers and their biological functions, the experiments of Arabidopsis thaliana AtSEP3 protein soluble expression in vitro were performed to construct a vector of prokaryotic expression, and investigate induced expression of recombinant proteins in Escherichia coli cells. The protein soluble expression was analyzed through the aspects of different protein domains, induction time, induction temperature, etc. Different structural domains and expression conditions were screened, and 0.1% IPTG inducing at 22 oC for 15 h was estimated as an optimal expression strategy. The nickel chelating resin was used to purify the protein in size exclusion chromatography (SEC) and the results indicated that AtSEP3 protein was present in the form of tetramer. PMID:26025404

  17. Using the BacMam Baculovirus System to Study Expression and Function of Recombinant Efflux Drug Transporters in Polarized Epithelial Cell Monolayers

    PubMed Central

    Fung, King Leung; Kapoor, Khyati; Pixley, Jessica N.; Talbert, Darrell J.; Kwit, Alexandra D.T.; Ambudkar, Suresh V.

    2016-01-01

    The ATP-binding cassette (ABC) transporter superfamily includes several membrane-bound proteins that are critical to drug pharmacokinetics and disposition. Pharmacologic evaluation of these proteins in vitro remains a challenge. In this study, human ABC transporters were expressed in polarized epithelial cell monolayers transduced using the BacMam baculovirus gene transfer system. The purpose of the study was to evaluate the efficacy of BacMam baculovirus to transduce cells grown in monolayers. In a porcine kidney cell line, LLC-PK1 cells, baculoviral transduction is successful only via the apical side of a polarized monolayer. We observed that recombinant ABC transporters were expressed on the cell surface with post-translational modification. Furthermore, sodium butyrate played a critical role in recombinant protein expression, and preincubation in the presence of tunicamycin or thapsigargin enhanced protein expression. Cells overexpressing human P-glycoprotein (P-gp) showed vectorial basolateral-to-apical transport of [3H]-paclitaxel, which could be reversed by the inhibitor tariquidar. Similarly, coexpression of human P-gp and ABCG2 in LLC-PK1 cells resulted in higher transport of mitoxantrone, which is a substrate for both transporters, than in either P-gp– or ABCG2-expressing cells alone. Taken together, our results indicate that a high level of expression of efflux transporters in a polarized cell monolayer is technically feasible with the BacMam baculovirus system PMID:26622052

  18. Over-expression of secreted proteins from mammalian cell lines

    PubMed Central

    Dalton, Annamarie C; Barton, William A

    2014-01-01

    Secreted mammalian proteins require the development of robust protein over-expression systems for crystallographic and biophysical studies of protein function. Due to complex disulfide bonds and distinct glycosylation patterns preventing folding and expression in prokaryotic expression hosts, many secreted proteins necessitate production in more complex eukaryotic expression systems. Here, we elaborate on the methods used to obtain high yields of purified secreted proteins from transiently or stably transfected mammalian cell lines. Among the issues discussed are the selection of appropriate expression vectors, choice of signal sequences for protein secretion, availability of fusion tags for enhancing protein stability and purification, choice of cell line, and the large-scale growth of cells in a variety of formats. PMID:24510886

  19. Robust expression of a bioactive mammalian protein in chlamydomonas chloroplast

    DOEpatents

    Mayfield, Stephen P.

    2010-03-16

    Methods and compositions are disclosed to engineer chloroplast comprising heterologous mammalian genes via a direct replacement of chloroplast Photosystem II (PSII) reaction center protein coding regions to achieve expression of recombinant protein above 5% of total protein. When algae is used, algal expressed protein is produced predominantly as a soluble protein where the functional activity of the peptide is intact. As the host algae is edible, production of biologics in this organism for oral delivery or proteins/peptides, especially gut active proteins, without purification is disclosed.

  20. Robust expression of a bioactive mammalian protein in Chlamydomonas chloroplast

    DOEpatents

    Mayfield, Stephen P

    2015-01-13

    Methods and compositions are disclosed to engineer chloroplast comprising heterologous mammalian genes via a direct replacement of chloroplast Photosystem II (PSII) reaction center protein coding regions to achieve expression of recombinant protein above 5% of total protein. When algae is used, algal expressed protein is produced predominantly as a soluble protein where the functional activity of the peptide is intact. As the host algae is edible, production of biologics in this organism for oral delivery of proteins/peptides, especially gut active proteins, without purification is disclosed.

  1. Purify First: rapid expression and purification of proteins from XMRV.

    PubMed

    Gillette, William K; Esposito, Dominic; Taylor, Troy E; Hopkins, Ralph F; Bagni, Rachel K; Hartley, James L

    2011-04-01

    Purifying proteins from recombinant sources is often difficult, time-consuming, and costly. We have recently instituted a series of improvements in our protein purification pipeline that allows much more accurate choice of expression host and conditions and purification protocols. The key elements are parallel cloning, small scale parallel expression and lysate preparation, and small scale parallel protein purification. Compared to analyzing expression data only, results from multiple small scale protein purifications predict success at scale-up with greatly improved reliability. Using these new procedures we purified eight of nine proteins from xenotropic murine leukemia virus-related virus (XMRV) on the first attempt at large scale. PMID:21146612

  2. Calreticulin: Roles in Cell-Surface Protein Expression

    PubMed Central

    Jiang, Yue; Dey, Sandeepa; Matsunami, Hiroaki

    2014-01-01

    In order to perform their designated functions, proteins require precise subcellular localizations. For cell-surface proteins, such as receptors and channels, they are able to transduce signals only when properly targeted to the cell membrane. Calreticulin is a multi-functional chaperone protein involved in protein folding, maturation, and trafficking. However, evidence has been accumulating that calreticulin can also negatively regulate the surface expression of certain receptors and channels. In these instances, depletion of calreticulin enhances cell-surface expression and function. In this review, we discuss the role of calreticulin with a focus on its negative effects on the expression of cell-surface proteins. PMID:25230046

  3. Proteomics beyond large-scale protein expression analysis.

    PubMed

    Boersema, Paul J; Kahraman, Abdullah; Picotti, Paola

    2015-08-01

    Proteomics is commonly referred to as the application of high-throughput approaches to protein expression analysis. Typical results of proteomics studies are inventories of the protein content of a sample or lists of differentially expressed proteins across multiple conditions. Recently, however, an explosion of novel proteomics workflows has significantly expanded proteomics beyond the analysis of protein expression. Targeted proteomics methods, for example, enable the analysis of the fine dynamics of protein systems, such as a specific pathway or a network of interacting proteins, and the determination of protein complex stoichiometries. Structural proteomics tools allow extraction of restraints for structural modeling and identification of structurally altered proteins on a proteome-wide scale. Other variations of the proteomic workflow can be applied to the large-scale analysis of protein activity, location, degradation and turnover. These exciting developments provide new tools for multi-level 'omics' analysis and for the modeling of biological networks in the context of systems biology studies. PMID:25636126

  4. HeLa Based Cell Free Expression Systems for Expression of Plasmodium Rhoptry Proteins.

    PubMed

    Yadavalli, Raghavendra; Sam-Yellowe, Tobili

    2015-01-01

    Malaria causes significant global morbidity and mortality. No routine vaccine is currently available. One of the major reasons for lack of a vaccine is the challenge of identifying suitable vaccine candidates. Malarial proteins expressed using prokaryotic and eukaryotic cell based expression systems are poorly glycosylated, generally insoluble and undergo improper folding leading to reduced immunogenicity. The wheat germ, rabbit reticulocyte lysate and Escherichia coli lysate cell free expression systems are currently used for expression of malarial proteins. However, the length of expression time and improper glycosylation of proteins still remains a challenge. We demonstrate expression of Plasmodium proteins in vitro using HeLa based cell free expression systems, termed "in vitro human cell free expression systems". The 2 HeLa based cell free expression systems transcribe mRNA in 75 min and 3 µl of transcribed mRNA is sufficient to translate proteins in 90 min. The 1-step expression system is a transcription and translation coupled expression system; the transcription and co-translation occurs in 3 hr. The process can also be extended for 6 hr by providing additional energy. In the 2-step expression system, mRNA is first transcribed and then added to the translation mix for protein expression. We describe how to express malaria proteins; a hydrophobic PF3D7_0114100 Maurer's Cleft - 2 transmembrane (PfMC-2TM) protein, a hydrophilic PF3D7_0925900 protein and an armadillo repeats containing protein PF3D7_1361800, using the HeLa based cell free expression system. The proteins are expressed in micro volumes employing 2-step and 1-step expression strategies. An affinity purification method to purify 25 µl of proteins expressed using the in vitro human cell free expression system is also described. Protein yield is determined by Bradford's assay and the expressed and purified proteins can be confirmed by western blotting analysis. Expressed recombinant proteins can be

  5. SUMO fusion technology for difficult-to-express proteins.

    PubMed

    Butt, Tauseef R; Edavettal, Suzanne C; Hall, John P; Mattern, Michael R

    2005-09-01

    The demands of structural and functional genomics for large quantities of soluble, properly folded proteins in heterologous hosts have been aided by advancements in the field of protein production and purification. Escherichia coli, the preferred host for recombinant protein expression, presents many challenges which must be surmounted in order to over-express heterologous proteins. These challenges include the proteolytic degradation of target proteins, protein misfolding, poor solubility, and the necessity for good purification methodologies. Gene fusion technologies have been able to improve heterologous expression by overcoming many of these challenges. The ability of gene fusions to improve expression, solubility, purification, and decrease proteolytic degradation will be discussed in this review. The main disadvantage, cleaving the protein fusion, will also be addressed. Focus will be given to the newly described SUMO fusion system and the improvements that this technology has advanced over traditional gene fusion systems. PMID:16084395

  6. Data presenting a modified bacterial expression vector for expressing and purifying Nus solubility-tagged proteins.

    PubMed

    Gupta, Nidhi; Wu, Heng; Terman, Jonathan R

    2016-09-01

    Bacteria are the predominant source for producing recombinant proteins but while many exogenous proteins are expressed, only a fraction of those are soluble. We have found that a new actin regulatory enzyme Mical is poorly soluble when expressed in bacteria but the use of a Nus fusion protein tag greatly increases its solubility. However, available vectors containing a Nus tag have been engineered in a way that hinders the separation of target proteins from the Nus tag during protein purification. We have now used recombinant DNA approaches to overcome these issues and reengineer a Nus solubility tag-containing bacterial expression vector. The data herein present a modified bacterial expression vector useful for expressing proteins fused to the Nus solubility tag and separating such target proteins from the Nus tag during protein purification. PMID:27547802

  7. pH dependent but not P-gp dependent bidirectional transport study of S-propranolol: the importance of passive diffusion

    PubMed Central

    Zheng, Yi; Benet, Leslie Z.; Okochi, Hideaki; Chen, Xijing

    2016-01-01

    Purpose Recent controversial publications, citing studies purporting to show that P-gp mediates the transport of propranolol, proposed that passive biological membrane transport is negligible. Based on the BDDCS, the extensively metabolized-highly permeable-highly soluble BDDCS class 1 drug, propranolol, shows a high passive permeability at concentrations unrestricted by solubility that can overwhelm any potential transporter effects. Here we reinvestigate the effects of passive diffusion and carrier-mediated transport on S-propranolol. Methods Bidirectional permeability and inhibition of efflux transport studies were carried out in MDCK, MDCK-MDR1 and Caco-2 cell lines at different concentrations. Transcellular permeability studies were conducted at different apical pHs in the rat jejunum Ussing chamber model and PAMPA system. Results S-propranolol exhibited efflux ratios lower than 1 in MDCK, MDCK-MDR1 and Caco-2 cells. No significant differences of Papp, B->A in the presence and absence of the efflux inhibitor GG918 were observed. However, an efflux ratio of 3.63 was found at apical pH 6.5 with significant decrease in Papp, A->B and increase in Papp, B->A compared to apical pH 7.4 in Caco-2 cell lines. The pH dependent permeability was confirmed in the Ussing chamber model. S-propranolol flux was unchanged during inhibition by verapamil and rifampin. Furthermore, pH dependent permeability was also observed in the PAMPA system. Conclusions S-propranolol does not exhibit active transport as proposed previously. The "false" positive efflux ratio can be explained by the pH partition theory. As expected, passive diffusion, but not active transport, plays the primary role in the permeability of the BDDCS class 1 drug propranolol. PMID:25690341

  8. Induction of Expression and Functional Activity of P-glycoprotein Efflux Transporter by Bioactive Plant Natural Products

    PubMed Central

    Abuznait, Alaa H.; Qosa, Hisham; O’Connell, Nicholas D.; Akbarian-Tefaghi, Jessica; Sylvester, Paul W.; El Sayed, Khalid A.; Kaddoumi, Amal

    2011-01-01

    The effect of bioactive plant natural products on the expression and functional activity of P-glycoprotein (P-gp) is poorly understood. Interactions of bioactive plant-based food and dietary supplements with P-gp can cause significant alteration of pharmacokinetic properties of P-gp substrate drugs when used in combination. This can augment toxicity and/or interfere with the drug’s therapeutic outcomes. This study investigated the effects of diverse commonly used plant natural products on the expression and activity of P-gp in human adenocarcinoma cells (LS-180). These natural products included the tobacco cembranoid (1S,2E,4R,6R,7E,11E)-2,7,11-cembratriene-4,6-diol (cembratriene), the palm oil-derived γ-tocotrienol, the extra-virgin olive oil-derived secoiridoid oleocanthal, and the triterpene acid asiatic acid derived from Melaleuca ericifolia and abundant in several other common plant dietary supplements. Treatment with 25 μM of cembratriene, oleocanthal, γ-tocotrienol, or asiatic acid showed 2.3-3.0-fold increase in P-gp expression as demonstrated by Western blotting. These results were consistent with those obtained by quantitative analysis of fluorescent micrographs for P-gp. Accumulation studies demonstrated 31-38% decrease in rhodamine 123 intracellular levels when LS-180 cells were treated with the investigated compounds as a result of P-gp induction. Bioactive natural products can up-regulate the P-gp expression and functionality, which may induce herb/food-drug interactions when concomitantly used with P-gp substrate drugs. PMID:21851848

  9. Aberrant expression of signaling proteins in essential thrombocythemia.

    PubMed

    Hui, Wuhan; Ye, Fei; Zhang, Wei; Liu, Congyan; Cui, Miao; Li, Wei; Xu, Juan; Zhang, David Y

    2013-09-01

    Dysregulated expression of signaling proteins may contribute to the pathophysiology of essential thrombocythemia (ET). This study aimed to characterize protein expression in ET and to correlate the dysregulated proteins with phenotypes and prognosis of ET patients. The expression of 128 proteins in peripheral blood neutrophils from 74 ET patients was assessed and compared with those from 29 healthy subjects and 35 polycythemia vera (PV) patients using protein pathway array. Fifteen proteins were differentially expressed between ET patients and normal controls. These dysregulated proteins were involved in the signaling pathways related with apoptosis and inflammation. Our results showed a significant overlap in protein expression between ET patients with JAK2V617F mutation and PV patients. In addition, nine proteins were associated with JAK2V617F mutation status in ET patients. Furthermore, estrogen receptor beta (ERβ) and Stat3 were independent risk factors for subsequent thrombosis during follow-up on multivariable analysis. Our study shows a broad dysregulation of signaling protein in ET patients, suggesting their roles in ET pathogenesis. The expression levels of ERβ and Stat3 could be promising predictors of subsequent thrombosis in ET patients. PMID:23639951

  10. Cloning and expression of special F protein from human liver

    PubMed Central

    Liu, Shu-Ye; Yu, Xin-Da; Song, Chun-Juan; Lu, Wei; Zhang, Jian-Dong; Shi, Xin-Rong; Duan, Ying; Zhang, Ju

    2007-01-01

    AIM: To clone human liver special F protein and to express it in a prokaryotic system. METHODS: Total RNA was isolated from human liver tissue and first-strand cDNA was reverse transcribed using the PCR reverse primer. Following this, cDNA of the F protein was ligated into the clone vector pUCm-T. The segment of F protein’s cDNA was subcloned into the expression vector pET-15b and transformed into E. coli BL21 (DE3) pLyss. Isopropy-β-D-thiogalactoside (IPTG) was then used to induce expression of the target protein. RESULTS: The cDNA clone of human liver special F protein (1134bp) was successfully produced, with the cDNA sequence being published in Gene-bank: DQ188836. We confirmed the expression of F protein by Western blot with a molecular weight of 43 kDa. The expressed protein accounted for 40% of the total protein extracted. CONCLUSION: F protein expresses cDNA clone in a prokaryotic system, which offers a relatively simple way of producing sufficient quantities of F protein and contributes to understanding the principal biological functions of this protein. PMID:17465469

  11. Relating protein adduction to gene expression changes: a systems approach

    PubMed Central

    Zhang, Bing; Shi, Zhiao; Duncan, Dexter T; Prodduturi, Naresh; Marnett, Lawrence J; Liebler, Daniel C

    2013-01-01

    Modification of proteins by reactive electrophiles such as the 4-hydroxy-2-nonenal (HNE) plays a critical role in oxidant-associated human diseases. However, little is known about protein adduction and the mechanism by which protein damage elicits adaptive effects and toxicity. We developed a systems approach for relating protein adduction to gene expression changes through the integration of protein adduction, gene expression, protein-DNA interaction, and protein-protein interaction data. Using a random walk strategy, we expanded a list of responsive transcription factors inferred from gene expression studies to upstream signaling networks, which in turn allowed overlaying protein adduction data on the network for the prediction of stress sensors and their associated regulatory mechanisms. We demonstrated the general applicability of transcription factor-based signaling network inference using 103 known pathways. Applying our workflow on gene expression and protein adduction data from HNE-treatment not only rediscovered known mechanisms of electrophile stress but also generated novel hypotheses regarding protein damage sensors. Although developed for analyzing protein adduction data, the framework can be easily adapted for phosphoproteomics and other types of protein modification data. PMID:21594272

  12. Trps1 is associated with the multidrug resistance of osteosarcoma by regulating MDR1 gene expression.

    PubMed

    Jia, Ming; Hu, Jing; Li, Weiwei; Su, Peng; Zhang, Hui; Zhang, Xiaofang; Zhou, Gengyin

    2014-03-01

    Multidrug resistance (MDR) is a significant clinical problem in the chemotherapy of osteosarcoma and has been linked to the cellular expression of several multidrug-efflux transporters such as MDR1/P-gp. Our inhibition of the transcription factor Trps1 led to repression of MDR1/P-gp while its overexpression resulted in upregulation of MDR1/P-gp. Flow cytometric analysis suggested Trps1 increased the release of several anti-cancer drugs, thus decreasing their accumulation. Immunohistochemical analysis of clinical samples indicated that the expression of Trps1 directly correlated with MDR1/P-gp. Trps1 inhibited TGFbeta-1 and directly bound to the MDR1 promoter. Our data demonstrate a role for Trps1 in the regulation of MDR1 expression in osteosarcoma. PMID:24491996

  13. Pannexin 2 protein expression is not restricted to the CNS

    PubMed Central

    Le Vasseur, Maxence; Lelowski, Jonathan; Bechberger, John F.; Sin, Wun-Chey; Naus, Christian C.

    2014-01-01

    Pannexins (Panx) are proteins homologous to the invertebrate gap junction proteins called innexins (Inx) and are traditionally described as transmembrane channels connecting the intracellular and extracellular compartments. Three distinct Panx paralogs (Panx1, Panx2 and Panx3) have been identified in vertebrates but previous reports on Panx expression and functionality focused primarily on Panx1 and Panx3 proteins. Several gene expression studies reported that Panx2 transcript is largely restricted to the central nervous system (CNS) hence suggesting that Panx2 might serve an important role in the CNS. However, the lack of suitable antibodies prevented the creation of a comprehensive map of Panx2 protein expression and Panx2 protein localization profile is currently mostly inferred from the distribution of its transcript. In this study, we characterized novel commercial monoclonal antibodies and surveyed Panx2 expression and distribution at the mRNA and protein level by real-time qPCR, Western blotting and immunofluorescence. Panx2 protein levels were readily detected in every tissue examined, even when transcriptional analysis predicted very low Panx2 protein expression. Furthermore, our results indicate that Panx2 transcriptional activity is a poor predictor of Panx2 protein abundance and does not correlate with Panx2 protein levels. Despite showing disproportionately high transcript levels, the CNS expressed less Panx2 protein than any other tissues analyzed. Additionally, we showed that Panx2 protein does not localize at the plasma membrane like other gap junction proteins but remains confined within cytoplasmic compartments. Overall, our results demonstrate that the endogenous expression of Panx2 protein is not restricted to the CNS and is more ubiquitous than initially predicted. PMID:25505382

  14. Expression strategies for structural studies of eukaryotic membrane proteins.

    PubMed

    Lyons, Joseph A; Shahsavar, Azadeh; Paulsen, Peter Aasted; Pedersen, Bjørn Panyella; Nissen, Poul

    2016-06-01

    Integral membrane proteins in eukaryotes are central to various cellular processes and key targets in structural biology, biotechnology and drug development. However, the number of available structures for eukaryotic membrane protein belies their physiological importance. Recently, the number of available eukaryotic membrane protein structures has been steadily increasing due to the development of novel strategies in construct design, expression and structure determination. Here, we examine the major expression systems exploited for eukaryotic membrane proteins. Additionally we strive to tabulate and describe the recent expression strategies in eukaryotic membrane protein structural biology. We find that a majority of targets have been expressed in advanced host systems and modified from their wild-type form with distinct focus on conformation and thermostabilisation. However, strategies for native protein purification should also be considered where possible, particularly in light of the recent advances in single particle cryo electron microscopy. PMID:27362979

  15. mir-29 regulates Mcl-1 protein expression and apoptosis.

    PubMed

    Mott, J L; Kobayashi, S; Bronk, S F; Gores, G J

    2007-09-13

    Cellular expression of Mcl-1, an anti-apoptotic Bcl-2 family member, is tightly regulated. Recently, Bcl-2 expression was shown to be regulated by microRNAs, small endogenous RNA molecules that regulate protein expression through sequence-specific interaction with messenger RNA. By analogy, we reasoned that Mcl-1 expression may also be regulated by microRNAs. We chose human immortalized, but non-malignant, H69 cholangiocyte and malignant KMCH cholangiocarcinoma cell lines for these studies, because Mcl-1 is dysregulated in cells with the malignant phenotype. By in silico analysis, we identified a putative target site in the Mcl-1 mRNA for the mir-29 family, and found that mir-29b was highly expressed in cholangiocytes. Interestingly, mir-29b was downregulated in malignant cells, consistent with Mcl-1 protein upregulation. Enforced mir-29b expression reduced Mcl-1 protein expression in KMCH cells. This effect was direct, as mir-29b negatively regulated the expression of an Mcl-1 3' untranslated region (UTR)-based reporter construct. Enforced mir-29b expression reduced Mcl-1 cellular protein levels and sensitized the cancer cells to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) cytotoxicity. Transfection of non-malignant cells (that express high levels of mir-29) with a locked-nucleic acid antagonist of mir-29b increased Mcl-1 levels and reduced TRAIL-mediated apoptosis. Thus mir-29 is an endogenous regulator of Mcl-1 protein expression, and thereby, apoptosis. PMID:17404574

  16. mir-29 Regulates Mcl-1 Protein Expression and Apoptosis

    PubMed Central

    Mott, Justin L.; Kobayashi, Shogo; Bronk, Steven F.; Gores, Gregory J.

    2008-01-01

    Cellular expression of Mcl-1, an anti-apoptotic Bcl-2 family member, is tightly regulated. Recently, Bcl-2 expression was shown to be regulated by microRNAs, small endogenous RNA molecules that regulate protein expression through sequence-specific interaction with messenger RNA. By analogy, we reasoned that Mcl-1 expression may also be regulated by microRNAs. We chose human immortalized, but non-malignant, H69 cholangiocyte and malignant KMCH cholangiocarcinoma cell lines for these studies because Mcl-1 is dysregulated in cells with the malignant phenotype. In silico analysis identified a putative target site in the Mcl-1 mRNA for the mir-29 family, and we found that mir-29b was highly expressed in cholangiocytes. Interestingly, mir-29b was downregulated in malignant cells, consistent with Mcl-1 protein upregulation. Enforced mir-29b expression reduced Mcl-1 protein expression in KMCH cells. This effect was direct, as mir-29b negatively regulated expression of an Mcl-1 3’ untranslated region (UTR)-based reporter construct. Enforced mir-29b expression reduced Mcl-1 cellular protein levels and sensitized the cancer cells to TRAIL cytotoxicity. Transfection of non-malignant cells (that express high levels of mir-29) with a locked-nucleic acid antagonist of mir-29b increased Mcl-1 levels and reduced TRAIL-mediated apoptosis. Thus mir-29 is an endogenous regulator of Mcl-1 protein expression and, thereby, apoptosis. PMID:17404574

  17. Maltose-Binding Protein (MBP), a Secretion-Enhancing Tag for Mammalian Protein Expression Systems

    PubMed Central

    Reuten, Raphael; Nikodemus, Denise; Oliveira, Maria B.; Patel, Trushar R.; Brachvogel, Bent; Breloy, Isabelle; Stetefeld, Jörg; Koch, Manuel

    2016-01-01

    Recombinant proteins are commonly expressed in eukaryotic expression systems to ensure the formation of disulfide bridges and proper glycosylation. Although many proteins can be expressed easily, some proteins, sub-domains, and mutant protein versions can cause problems. Here, we investigated expression levels of recombinant extracellular, intracellular as well as transmembrane proteins tethered to different polypeptides in mammalian cell lines. Strikingly, fusion of proteins to the prokaryotic maltose-binding protein (MBP) generally enhanced protein production. MBP fusion proteins consistently exhibited the most robust increase in protein production in comparison to commonly used tags, e.g., the Fc, Glutathione S-transferase (GST), SlyD, and serum albumin (ser alb) tag. Moreover, proteins tethered to MBP revealed reduced numbers of dying cells upon transient transfection. In contrast to the Fc tag, MBP is a stable monomer and does not promote protein aggregation. Therefore, the MBP tag does not induce artificial dimerization of tethered proteins and provides a beneficial fusion tag for binding as well as cell adhesion studies. Using MBP we were able to secret a disease causing laminin β2 mutant protein (congenital nephrotic syndrome), which is normally retained in the endoplasmic reticulum. In summary, this study establishes MBP as a versatile expression tag for protein production in eukaryotic expression systems. PMID:27029048

  18. Maltose-Binding Protein (MBP), a Secretion-Enhancing Tag for Mammalian Protein Expression Systems.

    PubMed

    Reuten, Raphael; Nikodemus, Denise; Oliveira, Maria B; Patel, Trushar R; Brachvogel, Bent; Breloy, Isabelle; Stetefeld, Jörg; Koch, Manuel

    2016-01-01

    Recombinant proteins are commonly expressed in eukaryotic expression systems to ensure the formation of disulfide bridges and proper glycosylation. Although many proteins can be expressed easily, some proteins, sub-domains, and mutant protein versions can cause problems. Here, we investigated expression levels of recombinant extracellular, intracellular as well as transmembrane proteins tethered to different polypeptides in mammalian cell lines. Strikingly, fusion of proteins to the prokaryotic maltose-binding protein (MBP) generally enhanced protein production. MBP fusion proteins consistently exhibited the most robust increase in protein production in comparison to commonly used tags, e.g., the Fc, Glutathione S-transferase (GST), SlyD, and serum albumin (ser alb) tag. Moreover, proteins tethered to MBP revealed reduced numbers of dying cells upon transient transfection. In contrast to the Fc tag, MBP is a stable monomer and does not promote protein aggregation. Therefore, the MBP tag does not induce artificial dimerization of tethered proteins and provides a beneficial fusion tag for binding as well as cell adhesion studies. Using MBP we were able to secret a disease causing laminin β2 mutant protein (congenital nephrotic syndrome), which is normally retained in the endoplasmic reticulum. In summary, this study establishes MBP as a versatile expression tag for protein production in eukaryotic expression systems. PMID:27029048

  19. Protein expression in Arabidopsis thaliana after chronic clinorotation

    NASA Technical Reports Server (NTRS)

    Piastuch, William C.; Brown, Christopher S.

    1994-01-01

    Soluble protein expression in Arabidopsis thaliana L. (Heynh.) leaf and stem tissue was examined after chronic clinorotation. Seeds of Arabidopsis were germinated and plants grown to maturity on horizontal or vertical slow-rotating clinostats (1 rpm) or in stationary vertical control units. Total soluble proteins and in vivo-labeled soluble proteins isolated from these plants were analyzed by two-dimensional sodium doedocyl sulfate polyacrylamide gel electrophoresis (SDS PAGE) and subsequent fluorography. Visual and computer analysis of the resulting protein patterns showed no significant differences in either total protein expression or in active protein synthesis between horizontal clinorotation and vertical controls in the Arabidopsis leaf and stem tissue. These results show chronic clinorotation does not cause gross changes in protein expression in Arabidopsis.

  20. Protein expression in Arabidopsis thaliana after chronic clinorotation

    NASA Technical Reports Server (NTRS)

    Piastuch, W. C.; Brown, C. S.

    1995-01-01

    Soluble protein expression in Arabidopsis thaliana L. (Heynh.) leaf and stem tissue was examined after chronic clinorotation. Seeds of Arabidopsis were germinated and plants grown to maturity on horizontal or vertical slow-rotating clinostats (1 rpm) or in stationary vertical control units. Total soluble proteins and in vivo-labeled soluble proteins isolated from these plants were analyzed by two-dimensional SDS PAGE and subsequent fluorography. Visual and computer analysis of the resulting protein patterns showed no significant differences in either total protein expression or in active protein synthesis between horizontal clinorotation and vertical controls in the Arabidopsis leaf and stem tissue. These results show chronic clinorotation does not cause gross changes in protein expression in Arabidopsis.

  1. Nucleic Acid Programmable Protein Array: A Just-In-Time Multiplexed Protein Expression and Purification Platform

    PubMed Central

    Qiu, Ji; LaBaer, Joshua

    2012-01-01

    Systematic study of proteins requires the availability of thousands of proteins in functional format. However, traditional recombinant protein expression and purification methods have many drawbacks for such study at the proteome level. We have developed an innovative in situ protein expression and capture system, namely NAPPA (nucleic acid programmable protein array), where C-terminal tagged proteins are expressed using an in vitro expression system and efficiently captured/purified by antitag antibodies coprinted at each spot. The NAPPA technology presented in this chapter enable researchers to produce and display fresh proteins just in time in a multiplexed high-throughput fashion and utilize them for various downstream biochemical researches of interest. This platform could revolutionize the field of functional proteomics with it ability to produce thousands of spatially separated proteins in high density with narrow dynamic rand of protein concentrations, reproducibly and functionally. PMID:21943897

  2. Expression of heat shock protein genes in insect stress responses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The heat shock proteins (HSPs) that are abundantly expressed in insects are important modulators of insect survival. Expression of HSP genes in insects is not only developmentally regulated, but also induced by various stressors in order to confer protection against such stressors. The expression o...

  3. Timosaponin A-III reverses multi-drug resistance in human chronic myelogenous leukemia K562/ADM cells via downregulation of MDR1 and MRP1 expression by inhibiting PI3K/Akt signaling pathway.

    PubMed

    Chen, Jie-Ru; Jia, Xiu-Hong; Wang, Hong; Yi, Ying-Jie; Wang, Jian-Yong; Li, You-Jie

    2016-05-01

    One of the major causes of failure in chemotherapy for patients with human chronic myelogenous leukemia (CML) is the acquisition of multidrug resistance (MDR). MDR is often associated with the overexpression of drug efflux transporters of the ATP-binding cassette (ABC) protein family. Timosaponin A-III (TAIII), a saponin isolated from the rhizome of Anemarrhena asphodeloides, has previously demonstrated the ability to suppress certain human tumor processes and the potential to be developed as an anticancer agent. Nevertheless, the ability of TAIII to reverse MDR has not yet been explored. In this study, the adriamycin (ADM) resistance reversal effect of TAIII in human CML K562/ADM cells and the underlying mechanism was investigated. The Cell Counting Kit-8 (CCK-8) assay showed that TAIII had a reversal effect on the drug resistance of K562/ADM cells. Flow cytometry assay showed increased intracellular accumulation of ADM after cells were pretreated with TAIII, and the changes in the accumulation of rhodamine-123 (Rho-123) and 5(6)-carboxyfluorescein diacetate (CFDA) dye in K562/ADM cells were determined to be similar to the changes of intracellular accumulation of ADM. After pretreatment of cells with TAIII, the decreasing expression of P-gp and MRP1 mRNA was examined by reverse transcription polymerase chain reaction (RT-PCR). Western blotting showed TAIII inhibiting P-gp and MRP1 expression depended on the PI3K/Akt signaling pathway by decreasing the activity of p-Akt. Moreover, wortmannin an inhibitor of PI3K/Akt signaling pathway has a strong inhibitory effect on the expression of p-Akt, P-gp and MRP1. Besides, the combined treatment with TAIII did not have an affect on wortmannin downregulation of p-Akt, P-gp and MRP1. Taken together, our findings demonstrate, for the first time, that TAIII induced MDR reversal through inhibition of P-gp and MRP1 expression and function with regained adriamycin sensitivity which might mainly correlate to the regulation of PI3K

  4. Evolution, diversification, and expression of KNOX proteins in plants

    PubMed Central

    Gao, Jie; Yang, Xue; Zhao, Wei; Lang, Tiange; Samuelsson, Tore

    2015-01-01

    The KNOX (KNOTTED1-like homeobox) transcription factors play a pivotal role in leaf and meristem development. The majority of these proteins are characterized by the KNOX1, KNOX2, ELK, and homeobox domains whereas the proteins of the KNATM family contain only the KNOX domains. We carried out an extensive inventory of these proteins and here report on a total of 394 KNOX proteins from 48 species. The land plant proteins fall into two classes (I and II) as previously shown where the class I family seems to be most closely related to the green algae homologs. The KNATM proteins are restricted to Eudicots and some species have multiple paralogs of this protein. Certain plants are characterized by a significant increase in the number of KNOX paralogs; one example is Glycine max. Through the analysis of public gene expression data we show that the class II proteins of this plant have a relatively broad expression specificity as compared to class I proteins, consistent with previous studies of other plants. In G. max, class I protein are mainly distributed in axis tissues and KNATM paralogs are overall poorly expressed; highest expression is in the early plumular axis. Overall, analysis of gene expression in G. max demonstrates clearly that the expansion in gene number is associated with functional diversification. PMID:26557129

  5. Expression of Recombinant Proteins in the Methylotrophic Yeast Pichia pastoris

    PubMed Central

    Weidner, Maria; Taupp, Marcus; Hallam, Steven J.

    2010-01-01

    Protein expression in the microbial eukaryotic host Pichia pastoris offers the possibility to generate high amounts of recombinant protein in a fast and easy to use expression system. As a single-celled microorganism P. pastoris is easy to manipulate and grows rapidly on inexpensive media at high cell densities. Being a eukaryote, P. pastoris is able to perform many of the post-translational modifications performed by higher eukaryotic cells and the obtained recombinant proteins undergo protein folding, proteolytic processing, disulfide bond formation and glycosylation [1]. As a methylotrophic yeast P. pastoris is capable of metabolizing methanol as its sole carbon source. The strong promoter for alcohol oxidase, AOX1, is tightly regulated and induced by methanol and it is used for the expression of the gene of interest. Accordingly, the expression of the foreign protein can be induced by adding methanol to the growth medium [2; 3]. Another important advantage is the secretion of the recombinant protein into the growth medium, using a signal sequence to target the foreign protein to the secretory pathway of P. pastoris. With only low levels of endogenous protein secreted to the media by the yeast itself and no added proteins to the media, a heterologous protein builds the majority of the total protein in the medium and facilitates following protein purification steps [3; 4]. The vector used here (pPICZαA) contains the AOX1 promoter for tightly regulated, methanol-induced expression of the gene of interest; the α-factor secretion signal for secretion of the recombinant protein, a Zeocin resistance gene for selection in both E. coli and Pichia and a C-terminal peptide containing the c-myc epitope and a polyhistidine (6xHis) tag for detection and purification of a recombinant protein. We also show western blot analysis of the recombinant protein using the specific Anti-myc-HRP antibody recognizing the c-myc epitope on the parent vector. PMID:20186119

  6. Engineering Cells to Improve Protein Expression

    PubMed Central

    Xiao, Su; Shiloach, Joseph; Betenbaugh, Michael J.

    2014-01-01

    Cellular engineering of bacteria, fungi, insect cells and mammalian cells is a promising methodology to improve recombinant protein production for structural, biochemical, and commercial applications. Increased understanding of the host organism biology has suggested engineering strategies targeting bottlenecks in transcription, translation, protein processing and secretory pathways, as well as cell growth and survival. A combination of metabolic engineering and synthetic biology has been used to improve the properties of cells for protein production, which has resulted in enhanced yields of multiple protein classes. PMID:24704806

  7. Optimizing transient recombinant protein expression in mammalian cells.

    PubMed

    Hopkins, Ralph F; Wall, Vanessa E; Esposito, Dominic

    2012-01-01

    Transient gene expression (TGE) in mammalian cells has become a routine process for expressing recombinant proteins in cell lines such as human embryonic kidney 293 and Chinese hamster ovary cells. The rapidly increasing need for recombinant proteins requires further improvements in TGE technology. While a great deal of focus has been directed toward optimizing the secretion of antibodies and other naturally secreted targets, much less work has been done on ways to improve cytoplasmic expression in mammalian cells. The benefits to protein production in mammalian cells, particularly for eukaryotic proteins, should be very significant - glycosylation and other posttranslational modifications will likely be native or near-native, solubility and protein folding would likely improve overexpression in heterologous hosts, and expression of proteins in their proper intracellular compartments is much more likely to occur. Improvements in this area have been slow, however, due to limited development of the cell culture processes needed for low-cost, higher-throughput expression in mammalian cells, and the relatively low diversity of DNA vectors for protein production in these systems. Here, we describe how the use of recombinational cloning, coupled with improvements in transfection protocols which increase speed and lower cost, can be combined to make mammalian cells much more amenable for routine recombinant protein expression. PMID:21987258

  8. Insulin influenced expression of myelin proteins in diabetic peripheral neuropathy.

    PubMed

    Rachana, Kuruvanthe S; Manu, Mallahalli S; Advirao, Gopal M

    2016-08-26

    Diabetic peripheral neuropathy (DPN) is one of the downstream complications of diabetes. This complication is caused by the deficiency of insulin action and subsequent hyperglycemia, but the details of their pathogenesis remain unclear. Hence, it is of critical importance to understand how such hormonal variation affects the expression of myelin proteins such as myelin basic protein (MBP) and myelin associated glycoprotein (MAG) in the peripheral nerve. An earlier report from our lab has demonstrated the expression of insulin receptors (IR) in Schwann cells (SCs) of sciatic nerve. To assess the neurotrophic role of insulin in diabetic neuropathy, we studied the expression of these myelin proteins under control, DPN and insulin treated DPN subjects at developmental stages. Further, the expression of these myelin proteins was correlated with the expression of insulin receptor. Expression of myelin proteins was significantly reduced in the diabetic model compared to normal, and upregulated in insulin treated diabetic rats. Similarly, an in vitro study was also carried out in SCs grown at high glucose and insulin treated conditions. The expression pattern of myelin proteins in SCs was comparable to that of in vivo samples. In addition, quantitative study of myelin genes by real time PCR has also showed the significant expression pattern change in the insulin treated and non-treated DPN subjects. Taken together, these results corroborate the critical importance of insulin as a neurotrophic factor in demyelinized neurons in diabetic neuropathy. PMID:27373589

  9. Major cancer protein amplifies global gene expression

    Cancer.gov

    Scientists may have discovered why a protein called MYC can provoke a variety of cancers. Like many proteins associated with cancer, MYC helps regulate cell growth. A new study carried out by researchers at the National Institutes of Health and colleagues

  10. Transient protein expression in three Pisum sativum (green pea) varieties.

    PubMed

    Green, Brian J; Fujiki, Masaaki; Mett, Valentina; Kaczmarczyk, Jon; Shamloul, Moneim; Musiychuk, Konstantin; Underkoffler, Susan; Yusibov, Vidadi; Mett, Vadim

    2009-02-01

    The expression of proteins in plants both transiently and via permanently transformed lines has been demonstrated by a number of groups. Transient plant expression systems, due to high expression levels and speed of production, show greater promise for the manufacturing of biopharmaceuticals when compared to permanent transformants. Expression vectors based on a tobacco mosaic virus (TMV) are the most commonly utilized and the primary plant used, Nicotiana benthamiana, has demonstrated the ability to express a wide range of proteins at levels amenable to purification. N. benthamiana has two limitations for its use; one is its relatively slow growth, and the other is its low biomass. To address these limitations we screened a number of legumes for transient protein expression. Using the alfalfa mosaic virus (AMV) and the cucumber mosaic virus (CMV) vectors, delivered via Agrobacterium, we were able to identify three Pisum sativum varieties that demonstrated protein expression transiently. Expression levels of 420 +/- 26.24 mg GFP/kgFW in the green pea variety speckled pea were achieved. We were also able to express three therapeutic proteins indicating promise for this system in the production of biopharmaceuticals. PMID:19156736

  11. Protein expression analyses at the single cell level.

    PubMed

    Ohno, Masae; Karagiannis, Peter; Taniguchi, Yuichi

    2014-01-01

    The central dogma of molecular biology explains how genetic information is converted into its end product, proteins, which are responsible for the phenotypic state of the cell. Along with the protein type, the phenotypic state depends on the protein copy number. Therefore, quantification of the protein expression in a single cell is critical for quantitative characterization of the phenotypic states. Protein expression is typically a dynamic and stochastic phenomenon that cannot be well described by standard experimental methods. As an alternative, fluorescence imaging is being explored for the study of protein expression, because of its high sensitivity and high throughput. Here we review key recent progresses in fluorescence imaging-based methods and discuss their application to proteome analysis at the single cell level. PMID:25197931

  12. Expression of trisomic proteins in Down syndrome model systems.

    PubMed

    Spellman, Claire; Ahmed, Md Mahiuddin; Dubach, Daphne; Gardiner, Katheleen J

    2013-01-10

    Down syndrome (DS) is the most common genetic aberration leading to intellectual disability. DS results from an extra copy of the long arm of human chromosome 21 (HSA21) and the increased expression of trisomic genes due to gene dosage. While expression in DS and DS models has been studied extensively at the RNA level, much less is known about expression of trisomic genes at the protein level. We have used quantitative Western blotting with antibodies to 20 proteins encoded by HSA21 to assess trisomic protein expression in lymphoblastoid cell lines (LCLs) from patients with DS and in brains from two mouse models of DS. These antibodies have recently become available and the 20 proteins largely have not been investigated previously for their potential contributions to the phenotypic features of DS. Twelve proteins had detectable expression in LCLs and three, CCT8, MX1 and PWP2, showed elevated levels in LCLs derived from patients with DS compared with controls. Antibodies against 15 proteins detected bands of appropriate sizes in lysates from mouse brain cortex. Genes for 12 of these proteins are trisomic in the Tc1 mouse model of DS, but only SIM2 and ZNF295 showed elevated expression in Tc1 cortex when compared with controls. Genes for eight of the 15 proteins are trisomic in the Ts65Dn mouse model of DS, but only ZNF294 was over expressed in cortex. Comparison of trisomic gene expression at the protein level with previous reports at the mRNA level showed many inconsistencies. These may be caused by natural inter-individual variability, differences in the age of mice analyzed, or post-transcriptional regulation of gene dosage effects. These antibodies provide resources for further investigation of the molecular basis of intellectual disability in DS. PMID:23103828

  13. Human SUMO fusion systems enhance protein expression and solubility.

    PubMed

    Wang, Zhongyuan; Li, Haolong; Guan, Wei; Ling, Haili; Wang, Zhiyong; Mu, Tianyang; Shuler, Franklin D; Fang, Xuexun

    2010-10-01

    A major challenge associated with recombinant protein production in Escherichia coli is generation of large quantities of soluble, functional protein. Yeast SUMO (small ubiquitin-related modifier), has been shown to enhance heterologous protein expression and solubility as fusion tag, however, the effects of human SUMOs on protein expression have not been investigated. Here we describe the use of human SUMO1 and SUMO2 as a useful gene fusion technology. Human SUMO1 and SUMO2 fusion expression vectors were constructed and tested in His-tag and ubiquitin fusion expression systems. Two difficult-to-express model proteins, matrix metalloprotease-13 (MMP13) and enhanced green fluorescence protein (eGFP) were fused to the C-terminus of the human SUMO1 and SUMO2 expression vectors. These constructs were expressed in E. coli and evaluation of MMP13 and eGFP expression and solubility was conducted. We found that both SUMO1 and SUMO2 had the ability to enhance the solubility of MMP13 and eGFP, with the SUMO2 tag having a more significant effect. Since fusion tags produce varying quantities of soluble proteins, we assessed the effect of SUMO2 coupled with ubiquitin (Ub). SUMO2-ubiquitin and ubiquitin-SUMO2 fusion expression plasmids were constructed with eGFP as a passenger protein. Following expression in E. coli, both plasmids could improve eGFP expression and solubility similar to the SUMO2 fusion and better than the ubiquitin fusion. The sequential order of SUMO2 and ubiquitin had little effect on expression and solubility of eGFP. Purification of eGFP from the gene fusion product, SUMO2-ubiquitin-eGFP, involved cleavage by a deubiquitinase (Usp2-cc) and Ni-Sepharose column chromatography. The eGFP protein was purified to high homogeneity. In summary, human SUMO1 and SUMO2 are useful gene fusion technologies enhancing the expression, solubility and purification of model heterologous proteins. PMID:20457256

  14. Induction of a multixenobiotic resistance protein (MXR) in the Asiatic clam Corbicula fluminea after heavy metals exposure.

    PubMed

    Achard, M; Baudrimont, M; Boudou, A; Bourdineaud, J P

    2004-05-12

    Multixenobiotic resistance mechanisms (MXR) related to the mammalian P-glycoprotein multidrug transporter protein (P-gp) are known to occur in several marine invertebrates. In the present work, we report on the induction of an MXR protein by various heavy metals in the gills of the freshwater clam Corbicula fluminea. The evaluation of the MXR protein level was assessed by Western blot using a specific monoclonal antibody raised against the human P-gp (C219). A field transplantation experiment, where clams were caged in a gradient relative to an industrial site, demonstrated a positive relationship between MXR levels and (a) metal pollution (Cd and Zn) in the environment and (b) metal bioaccumulation in the gills. To establish this correlative relationship, clams were exposed to different levels of cadmium (15-60 microg l(-1)) for up to 15 days in a controlled laboratory experiment. MXR protein levels increased in time for all treatments (including the control). However, the highest levels of MXR protein titer were expressed in clams that had been exposed to the lowest dose of cadmium. The causes for this observed inverse relationship between the exposure dose and the MXR induction is discussed. MXR protein titer was also shown to be induced by other heavy metals (zinc, inorganic mercury, and copper). PMID:15084411

  15. In vitro potential modulation of baicalin and baicalein on P-glycoprotein activity and expression in Caco-2 cells and rat gut sacs.

    PubMed

    Miao, Qing; Wang, Zhiyong; Zhang, Yuanyuan; Miao, Peipei; Zhao, Yuanyuan; Zhang, Yujie; Ma, Shuangcheng

    2016-09-01

    Context Previous studies have shown that Scutellariae Radix, the dried root of Scutellaria baicalensis Georgi (Labiatae), has a certain inhibitory effect on P-glycoprotein (P-gp), but the effects of its main active constituents on P-gp are still ambiguous. Objectives In vitro studies were performed to investigate the effects of its main active constituents (baicalin and its aglycone, baicalein) on the activity and expression of P-gp in intestine using Caco-2 cells and rat gut sacs. Materials and methods In Caco-2 cell experiments, the effects of baicalin and baicalein on P-gp activity were investigated using a P-gp substrate, rhodamine 123 and non-substrate fluorescein Na, by determining their intracellular fluorescence accumulation, and their effects on P-gp expression were determined using flow cytometry. In addition, rat gut sac model was selected to investigate the effects of baicalin and baicalein on the transport of verapamil, a classical P-gp substrate. The gut sacs of male Sprague-Dawley rats were filled with 0.4 mL the test solution contained verapamil (0.2575 mg/mL) and the drugs [baicalin and baicalein, at concentrations of 1/8 IC50 (59.875, 41.5 μg/mL), 1/4 IC50 (119.75, 83 μg/mL) and 1/2 IC50 (239.5, 166 μg/mL)], and then incubated in Tyrode's solution for a period of time. After termination of the incubation, the incubated solution was processed for the subsequent detection. Results According to the results of MTT assay, the IC50 values of verapamil, baicalin and baicalein were 104, 479, 332 μg/mL, respectively. The obtained results from the two models were confirmed mutually. As a result, baicalin exhibited no obvious effect on intracellular accumulation of Rh-123, and almost had no effect on P-gp expression and verapamil transportation, while baicalein significantly increased intracellular accumulation of Rh-123 (p < 0.01), down-regulated P-gp expression (p < 0.01) and increased the transport of verapamil (p < 0

  16. Protein Expression Dynamics During Postnatal Mouse Brain Development

    PubMed Central

    Laeremans, Annelies; Van de Plas, Babs; Clerens, Stefan; Van den Bergh, Gert; Arckens, Lutgarde; Hu, Tjing-Tjing

    2013-01-01

    We explored differential protein expression profiles in the mouse forebrain at different stages of postnatal development, including 10-day (P10), 30-day (P30), and adult (Ad) mice, by large-scale screening of proteome maps using two-dimensional difference gel electrophoresis. Mass spectrometry analysis resulted in the identification of 251 differentially expressed proteins. Most molecular changes were observed between P10 compared to both P30 and Ad. Computational ingenuity pathway analysis (IPA) confirmed these proteins as crucial molecules in the biological function of nervous system development. Moreover, IPA revealed Semaphorin signaling in neurons and the protein ubiquitination pathway as essential canonical pathways in the mouse forebrain during postnatal development. For these main biological pathways, the transcriptional regulation of the age-dependent expression of selected proteins was validated by means of in situ hybridization. In conclusion, we suggest that proteolysis and neurite outgrowth guidance are key biological processes, particularly during early brain maturation. PMID:25157209

  17. Proteins and an Inflammatory Network Expressed in Colon Tumors

    PubMed Central

    Zhu, Wenhong; Fang, Changming; Gramatikoff, Kosi; Niemeyer, Christina C.; Smith, Jeffrey W.

    2011-01-01

    The adenomatous polyposis coli (APC) protein is crucial to homeostasis of normal intestinal epithelia because it suppresses the β-catenin/TCF pathway. Consequently, loss or mutation of the APC gene causes colorectal tumors in humans and mice. Here, we describe our use of Multidimensional Protein Identification Technology (MudPIT) to compare protein expression in colon tumors to that of adjacent healthy colon tissue from ApcMin/+ mice. Twenty-seven proteins were found to be up-regulated in colon tumors and twenty-five down-regulated. As an extension of the proteomic analysis, the differentially expressed proteins were used as “seeds” to search for co-expressed genes. This approach revealed a co-expression network of 45 genes that is up-regulated in colon tumors. Members of the network include the antibacterial peptide cathelicidin (CAMP), Toll-like receptors (TLRs), IL-8, and triggering receptor expressed on myeloid cells 1 (TREM1). The co-expression network is associated with innate immunity and inflammation, and there is significant concordance between its connectivity in humans versus mice (Friedman: p value = 0.0056). This study provides new insights into the proteins and networks that are likely to drive the onset and progression of colon cancer. PMID:21366352

  18. GTP Cyclohydrolase I Expression, Protein, and Activity Determine Intracellular Tetrahydrobiopterin Levels, Independent of GTP Cyclohydrolase Feedback Regulatory Protein Expression

    PubMed Central

    Tatham, Amy L.; Crabtree, Mark J.; Warrick, Nicholas; Cai, Shijie; Alp, Nicholas J.; Channon, Keith M.

    2009-01-01

    GTP cyclohydrolase I (GTPCH) is a key enzyme in the synthesis of tetrahydrobiopterin (BH4), a required cofactor for nitricoxide synthases and aromatic amino acid hydroxylases. Alterations of GTPCH activity and BH4 availability play an important role in human disease. GTPCH expression is regulated by inflammatory stimuli, in association with reduced expression of GTP cyclohydrolase feedback regulatory protein (GFRP). However, the relative importance of GTPCH expression versus GTPCH activity and the role of GFRP in relation to BH4 bioavailability remain uncertain. We investigated these relationships in a cell line with tet-regulated GTPCH expression and in the hph-1 mouse model of GTPCH deficiency. Doxycycline exposure resulted in a dose-dependent decrease in GTPCH protein and activity, with a strong correlation between GTPCH expression and BH4 levels (r2 = 0.85, p < 0.0001). These changes in GTPCH and BH4 had no effect on GFRP expression or protein levels. GFRP overexpression and knockdown in tet-GCH cells did not alter GTPCH activity or BH4 levels, and GTPCH-specific knockdown in sEnd.1 endothelial cells had no effect on GFRP protein. In mouse liver we observed a graded reduction of GTPCH expression, protein, and activity, from wild type, heterozygote, to homozygote littermates, with a striking linear correlation between GTPCH expression and BH4 levels (r2 = 0.82, p < 0.0001). Neither GFRP expression nor protein differed between wild type, heterozygote, nor homozygote mice, despite the substantial differences in BH4. We suggest that GTPCH expression is the primary regulator of BH4 levels, and changes in GTPCH or BH4 are not necessarily accompanied by changes in GFRP expression. PMID:19286659

  19. GTP cyclohydrolase I expression, protein, and activity determine intracellular tetrahydrobiopterin levels, independent of GTP cyclohydrolase feedback regulatory protein expression.

    PubMed

    Tatham, Amy L; Crabtree, Mark J; Warrick, Nicholas; Cai, Shijie; Alp, Nicholas J; Channon, Keith M

    2009-05-15

    GTP cyclohydrolase I (GTPCH) is a key enzyme in the synthesis of tetrahydrobiopterin (BH4), a required cofactor for nitricoxide synthases and aromatic amino acid hydroxylases. Alterations of GTPCH activity and BH4 availability play an important role in human disease. GTPCH expression is regulated by inflammatory stimuli, in association with reduced expression of GTP cyclohydrolase feedback regulatory protein (GFRP). However, the relative importance of GTPCH expression versus GTPCH activity and the role of GFRP in relation to BH4 bioavailability remain uncertain. We investigated these relationships in a cell line with tet-regulated GTPCH expression and in the hph-1 mouse model of GTPCH deficiency. Doxycycline exposure resulted in a dose-dependent decrease in GTPCH protein and activity, with a strong correlation between GTPCH expression and BH4 levels (r(2) = 0.85, p < 0.0001). These changes in GTPCH and BH4 had no effect on GFRP expression or protein levels. GFRP overexpression and knockdown in tet-GCH cells did not alter GTPCH activity or BH4 levels, and GTPCH-specific knockdown in sEnd.1 endothelial cells had no effect on GFRP protein. In mouse liver we observed a graded reduction of GTPCH expression, protein, and activity, from wild type, heterozygote, to homozygote littermates, with a striking linear correlation between GTPCH expression and BH4 levels (r(2) = 0.82, p < 0.0001). Neither GFRP expression nor protein differed between wild type, heterozygote, nor homozygote mice, despite the substantial differences in BH4. We suggest that GTPCH expression is the primary regulator of BH4 levels, and changes in GTPCH or BH4 are not necessarily accompanied by changes in GFRP expression. PMID:19286659

  20. Small-scale expression of proteins in E. coli.

    PubMed

    Zerbs, Sarah; Giuliani, Sarah; Collart, Frank

    2014-01-01

    Proteins participate in virtually every cellular activity, and a knowledge of protein function is essential for an understanding of biological systems. However, protein diversity necessitates the application of an array of in vivo and in vitro approaches for characterization of the functional and biochemical properties of proteins. Methods that enable production of proteins for in vitro studies are critical for determination of the molecular, kinetic, and thermodynamic properties of these molecules. Ideally, proteins could be purified from the original source; however, the native host is often unsuitable for a number of reasons. Consequently, systems for heterologous protein production are commonly used to produce large amounts of protein. Heterologous expression hosts are chosen using a number of criteria, including genetic tractability, advantageous production or processing characteristics (secretion or posttranslational modifications), or economy of time and growth requirements. The subcloning process also provides an opportunity to introduce purification tags, epitope tags, fusions, truncations, and mutations into the coding sequence that may be useful in downstream purification or characterization applications. Bacterial systems for heterologous protein expression have advantages in ease of use, cost, short generation times, and scalability. These expression systems have been widely used by high-throughput protein production projects and often represent an initial experiment for any expression target. Escherichia coli has been studied for many years as a model bacterial organism and is one of the most popular hosts for heterologous protein expression (Terpe, 2006). Its protein production capabilities have been intensively studied, and the ease of genetic manipulation in this organism has led to the development of strains engineered exclusively for use in protein expression. These resources are widely available from commercial sources and public repositories

  1. High-Throughput Baculovirus Expression System for Membrane Protein Production.

    PubMed

    Kalathur, Ravi C; Panganiban, Marinela; Bruni, Renato

    2016-01-01

    The ease of use, robustness, cost-effectiveness, and posttranslational machinery make baculovirus expression system a popular choice for production of eukaryotic membrane proteins. This system can be readily adapted for high-throughput operations. This chapter outlines the techniques and procedures for cloning, transfection, small-scale production, and purification of membrane protein samples in a high-throughput manner. PMID:27485337

  2. Ubiquitin-dependent proteolysis in yeast cells expressing neurotoxic proteins

    PubMed Central

    Braun, Ralf J.

    2015-01-01

    Critically impaired protein degradation is discussed to contribute to neurodegenerative disorders, including Parkinson's, Huntington's, Alzheimer's, and motor neuron diseases. Misfolded, aggregated, or surplus proteins are efficiently degraded via distinct protein degradation pathways, including the ubiquitin-proteasome system, autophagy, and vesicular trafficking. These pathways are regulated by covalent modification of target proteins with the small protein ubiquitin and are evolutionary highly conserved from humans to yeast. The yeast Saccharomyces cerevisiae is an established model for deciphering mechanisms of protein degradation, and for the elucidation of pathways underlying programmed cell death. The expression of human neurotoxic proteins triggers cell death in yeast, with neurotoxic protein-specific differences. Therefore, yeast cell death models are suitable for analyzing the role of protein degradation pathways in modulating cell death upon expression of disease-causing proteins. This review summarizes which protein degradation pathways are affected in these yeast models, and how they are involved in the execution of cell death. I will discuss to which extent this mimics the situation in other neurotoxic models, and how this may contribute to a better understanding of human disorders. PMID:25814926

  3. Translation Levels Control Multi-Spanning Membrane Protein Expression

    PubMed Central

    Brown, Cecilia; Bostrom, Jenny; Fuh, Germaine; Lee, Chingwei V.; Huang, Arthur; Vandlen, Richard L.; Yansura, Daniel G.

    2012-01-01

    Attempts to express eukaryotic multi-spanning membrane proteins at high-levels have been generally unsuccessful. In order to investigate the cause of this limitation and gain insight into the rate limiting processes involved, we have analyzed the effect of translation levels on the expression of several human membrane proteins in Escherichia coli (E. coli). These results demonstrate that excessive translation initiation rates of membrane proteins cause a block in protein synthesis and ultimately prevent the high-level accumulation of these proteins. Moderate translation rates allow coupling of peptide synthesis and membrane targeting, resulting in a significant increase in protein expression and accumulation over time. The current study evaluates four membrane proteins, CD20 (4-transmembrane (TM) helixes), the G-protein coupled receptors (GPCRs, 7-TMs) RA1c and EG-VEGFR1, and Patched 1 (12-TMs), and demonstrates the critical role of translation initiation rates in the targeting, insertion and folding of integral membrane proteins in the E. coli membrane. PMID:22563408

  4. Proteomic analysis of Clostridium thermocellum core metabolism: relative protein expression profiles and growth phase-dependent changes in protein expression

    PubMed Central

    2012-01-01

    Background Clostridium thermocellum produces H2 and ethanol, as well as CO2, acetate, formate, and lactate, directly from cellulosic biomass. It is therefore an attractive model for biofuel production via consolidated bioprocessing. Optimization of end-product yields and titres is crucial for making biofuel production economically feasible. Relative protein expression profiles may provide targets for metabolic engineering, while understanding changes in protein expression and metabolism in response to carbon limitation, pH, and growth phase may aid in reactor optimization. We performed shotgun 2D-HPLC-MS/MS on closed-batch cellobiose-grown exponential phase C. thermocellum cell-free extracts to determine relative protein expression profiles of core metabolic proteins involved carbohydrate utilization, energy conservation, and end-product synthesis. iTRAQ (isobaric tag for relative and absolute quantitation) based protein quantitation was used to determine changes in core metabolic proteins in response to growth phase. Results Relative abundance profiles revealed differential levels of putative enzymes capable of catalyzing parallel pathways. The majority of proteins involved in pyruvate catabolism and end-product synthesis were detected with high abundance, with the exception of aldehyde dehydrogenase, ferredoxin-dependent Ech-type [NiFe]-hydrogenase, and RNF-type NADH:ferredoxin oxidoreductase. Using 4-plex 2D-HPLC-MS/MS, 24% of the 144 core metabolism proteins detected demonstrated moderate changes in expression during transition from exponential to stationary phase. Notably, proteins involved in pyruvate synthesis decreased in stationary phase, whereas proteins involved in glycogen metabolism, pyruvate catabolism, and end-product synthesis increased in stationary phase. Several proteins that may directly dictate end-product synthesis patterns, including pyruvate:ferredoxin oxidoreductases, alcohol dehydrogenases, and a putative bifurcating hydrogenase

  5. Recombinant protein expression in Escherichia coli: advances and challenges

    PubMed Central

    Rosano, Germán L.; Ceccarelli, Eduardo A.

    2014-01-01

    Escherichia coli is one of the organisms of choice for the production of recombinant proteins. Its use as a cell factory is well-established and it has become the most popular expression platform. For this reason, there are many molecular tools and protocols at hand for the high-level production of heterologous proteins, such as a vast catalog of expression plasmids, a great number of engineered strains and many cultivation strategies. We review the different approaches for the synthesis of recombinant proteins in E. coli and discuss recent progress in this ever-growing field. PMID:24860555

  6. A study protocol for quantitative targeted absolute proteomics (QTAP) by LC-MS/MS: application for inter-strain differences in protein expression levels of transporters, receptors, claudin-5, and marker proteins at the blood–brain barrier in ddY, FVB, and C57BL/6J mice

    PubMed Central

    2013-01-01

    Proteomics has opened a new horizon in biological sciences. Global proteomic analysis is a promising technology for the discovery of thousands of proteins, post-translational modifications, polymorphisms, and molecular interactions in a variety of biological systems. The activities and roles of the identified proteins must also be elucidated, but this is complicated by the inability of conventional proteomic methods to yield quantitative information for protein expression. Thus, a variety of biological systems remain “black boxes”. Quantitative targeted absolute proteomics (QTAP) enables the determination of absolute expression levels (mol) of any target protein, including low-abundance functional proteins, such as transporters and receptors. Therefore, QTAP will be useful for understanding the activities and roles of individual proteins and their differences, including normal/disease, human/animal, or in vitro/in vivo. Here, we describe the study protocols and precautions for QTAP experiments including in silico target peptide selection, determination of peptide concentration by amino acid analysis, setup of selected/multiple reaction monitoring (SRM/MRM) analysis in liquid chromatography–tandem mass spectrometry, preparation of protein samples (brain capillaries and plasma membrane fractions) followed by the preparation of peptide samples, simultaneous absolute quantification of target proteins by SRM/MRM analysis, data analysis, and troubleshooting. An application of QTAP in biological sciences was introduced that utilizes data from inter-strain differences in the protein expression levels of transporters, receptors, tight junction proteins and marker proteins at the blood–brain barrier in ddY, FVB, and C57BL/6J mice. Among 18 molecules, 13 (abcb1a/mdr1a/P-gp, abcc4/mrp4, abcg2/bcrp, slc2a1/glut1, slc7a5/lat1, slc16a1/mct1, slc22a8/oat3, insr, lrp1, tfr1, claudin-5, Na+/K+-ATPase, and γ-gtp) were detected in the isolated brain capillaries, and their

  7. Mapping the expression of soluble olfactory proteins in the honeybee.

    PubMed

    Dani, Francesca Romana; Iovinella, Immacolata; Felicioli, Antonio; Niccolini, Alberto; Calvello, Maria Antonietta; Carucci, Maria Giovanna; Qiao, Huili; Pieraccini, Giuseppe; Turillazzi, Stefano; Moneti, Gloriano; Pelosi, Paolo

    2010-04-01

    Chemical communication in insects is mediated by soluble binding proteins, belonging to two large families, Odorant-binding Proteins (OBPs) and Chemosensory Proteins (CSPs). Recently, evidence has been provided that OBPs are involved in recognition of chemical stimuli. We therefore decided to investigate the expression of OBPs and CSPs in the honeybee at the protein level, using a proteomic approach. Our results are in agreement with previous reports of expression at the RNA level and show that 12 of the 21 OBPs predicted in the genome of the honeybee Apis mellifera and 2 of the 6 CSPs are present in the foragers' antennae, while the larvae express only three OBPs and a single CSP. MALDI mass spectrometry on crude antennal extracts and MALDI profiling on sections of antennae demonstrated that these techniques can be applied to investigate individual differences in the expression of abundant proteins, such as OBPs and CSPs, as well as to detect the presence of proteins in different regions of the antenna. Finally, as part of a project aimed at the characterization of all OBPs and CSPs of the honeybee, we expressed 5 OBPs and 4 CSPs in a bacterial system and measured their affinity to a number of ligands. Clear differences in their binding spectra have been observed between OBPs, as well as CSPs. PMID:20155982

  8. Cell-Free Expression of G Protein-Coupled Receptors.

    PubMed

    Segers, Kenneth; Masure, Stefan

    2015-01-01

    The large-scale production of recombinant G protein-coupled receptors (GPCRs) is one of the major bottlenecks that hamper functional and structural studies of this important class of integral membrane proteins. Heterologous overexpression of GPCRs often results in low yields of active protein, usually due to a combination of several factors, such as low expression levels, protein insolubility, host cell toxicity, and the need to use harsh and often denaturing detergents (e.g., SDS, LDAO, OG, and DDM, among others) to extract the recombinant receptor from the host cell membrane. Many of these problematic issues are inherently linked to cell-based expression systems and can therefore be circumvented by the use of cell-free systems. In this unit, we provide a range of protocols for the production of GPCRs in a cell-free expression system. Using this system, we typically obtain GPCR expression levels of ∼1 mg per ml of reaction mixture in the continuous-exchange configuration. Although the protocols in this unit have been optimized for the cell-free expression of GPCRs, they should provide a good starting point for the production of other classes of membrane proteins, such as ion channels, aquaporins, carrier proteins, membrane-bound enzymes, and even large molecular complexes. PMID:26237676

  9. Expression of Eukaryotic Membrane Proteins in Pichia pastoris.

    PubMed

    Hartmann, Lucie; Kugler, Valérie; Wagner, Renaud

    2016-01-01

    A key point when it comes to heterologous expression of eukaryotic membrane proteins (EMPs) is the choice of the best-suited expression platform. The yeast Pichia pastoris has proven to be a very versatile system showing promising results in a growing number of cases. Indeed, its particular methylotrophic characteristics combined to the very simple handling of a eukaryotic microorganism that possesses the majority of mammalian-like machineries make it a very competitive expression system for various complex proteins, in amounts compatible with functional and structural studies. This chapter describes a set of robust methodologies routinely used for the successful expression of a variety of EMPs, going from yeast transformation with the recombinant plasmid to the analysis of the quality and quantity of the proteins produced. PMID:27485335

  10. Individual expression of influenza virus PA protein induces degradation of coexpressed proteins.

    PubMed Central

    Sanz-Ezquerro, J J; de la Luna, S; Ortín, J; Nieto, A

    1995-01-01

    In the process of in vivo reconstitution of influenza virus transcriptase-replicase complex, an inhibitory effect was observed when the level of PA protein expression was increased. This inhibition was paralleled by a decrease in the accumulation of the other influenza virus core proteins. The sole expression of PA protein was sufficient to reduce the accumulation level of the proteins encoded by the coexpressed genes. The PA effect was observed upon influenza virus and non-influenza virus proteins and independently of the expression system chosen and the origin of cell line used. The expression of PA protein did not induce variations in the translation of the target proteins but did induce variations on their half-lives, which were clearly reduced. A functional PA subunit seems to be necessary to induce this negative effect, because an inactive point mutant was unable to decrease the steady-state levels or the half-lives of the reporter proteins. The PA effect was observed as early as 5 h after its expression, and continuous synthesis of proteins was not required for performance of its biological activity. The results presented represent the first biological activity of individually expressed PA polymerase subunit. PMID:7884889

  11. Differential Protein Expression in Congenital and Acquired Cholesteatomas

    PubMed Central

    Kim, Sung Huhn; Choi, Jae Young

    2015-01-01

    Congenital cholesteatomas are epithelial lesions that present as an epithelial pearl behind an intact eardrum. Congenital and acquired cholesteatomas progress quite differently from each other and progress patterns can provide clues about the unique origin and pathogenesis of the abnormality. However, the exact pathogenic mechanisms by which cholesteatomas develop remain unknown. In this study, key proteins that directly affect cholesteatoma pathogenesis are investigated with proteomics and immunohistochemistry. Congenital cholesteatoma matrices and retroauricular skin were harvested during surgery in 4 patients diagnosed with a congenital cholesteatoma. Tissue was also harvested from the retraction pocket in an additional 2 patients during middle ear surgery. We performed 2-dimensional (2D) electrophoresis to detect and analyze spots that are expressed only in congenital cholesteatoma and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF/MS) to separate proteins by molecular weight. Protein expression was confirmed by immunohistochemical staining. The image analysis of 2D electrophoresis showed that 4 congenital cholesteatoma samples had very similar protein expression patterns and that 127 spots were exclusively expressed in congenital cholesteatomas. Of these 127 spots, 10 major spots revealed the presence of titin, forkhead transcription activator homolog (FKH 5–3), plectin 1, keratin 10, and leucine zipper protein 5 by MALDI-TOF/MS analysis. Immunohistochemical staining showed that FKH 5–3 and titin were expressed in congenital cholesteatoma matrices, but not in acquired cholesteatomas. Our study shows that protein expression patterns are completely different in congenital cholesteatomas, acquired cholesteatomas, and skin. Moreover, non-epithelial proteins, including FKH 5–3 and titin, were unexpectedly expressed in congenital cholesteatoma tissue. Our data indicates that congenital cholesteatoma origins may differ

  12. Expression of microtubule-associated protein 2 by reactive astrocytes.

    PubMed Central

    Geisert, E E; Johnson, H G; Binder, L I

    1990-01-01

    After an injury to the central nervous system, a dramatic change in the astrocytes bordering the wound occurs. The most characteristic feature of this process, termed reactive gliosis, is the upregulation of the intermediate filament protein, glial fibrillary acidic protein. In the present study, we show that reactive astrocytes express high levels of microtubule-associated protein 2 (MAP-2), a protein normally found in the somatodendritic compartment of neurons. When sections of injured brain are double-stained with antibodies directed against MAP-2 and glial fibrillary protein, all of the reactive astrocytes are found to contain MAP-2. The high levels of this protein appear to represent a permanent change in reactive astrocytes. In parallel quantitative studies, an elevated level of MAP-2 in the injured brain is confirmed by an immunoblot analysis of injured and normal white matter. This report demonstrates the direct involvement of a microtubule protein in the process of reactive gliosis. Images PMID:1692628

  13. Expressing and purifying membrane transport proteins in high yield.

    PubMed

    Hale, Calvin C; Hill, Chananada K; Price, Elmer M; Bossuyt, Julie

    2002-01-01

    Structural analysis of native or recombinant membrane transport proteins has been hampered by the lack of effective methodologies to purify sufficient quantities of active protein. We addressed this problem by expressing a polyhistidine tagged construct of the cardiac sodium-calcium exchanger (NCX1) in Trichoplusia ni larvae (caterpillars) from which membrane vesicles were prepared. Larvae vesicles containing recombinant NCX1-his protein supported NCX1 transport activity that was mechanistically not different from activity in native cardiac sarcolemmal vesicles although the specific activity was reduced. SDS-PAGE and Western blot analysis demonstrated the presence of both the 120 and 70 kDa forms of the NCX1 protein. Larvae vesicle proteins were solubilized in sodium cholate detergent and fractionated on a chelated Ni(2+) affinity chromatography column. After extensive washing, eluted fractions were mixed with soybean phospholipids and reconstituted. The resulting proteoliposomes contained NCX1 activity suggesting the protein retained native conformation. SDS-PAGE revealed two major bands at 120 and 70 kDa. Purification of large amounts of active NCX1 via this methodology should facilitate biophysical analysis of the protein. The larva expression system has broad-based application for membrane proteins where expression and purification of quantities required for physical analyses is problematic. PMID:11741710

  14. EGFR/HER2 inhibitors effectively reduce the malignant potential of MDR breast cancer evoked by P-gp substrates in vitro and in vivo.

    PubMed

    Jin, Yiting; Zhang, Wei; Wang, Hongying; Zhang, Zijing; Chu, Chengyu; Liu, Xiuping; Zou, Qiang

    2016-02-01

    Multidrug resistance (MDR) induced by chemotherapy in breast cancer frequently leads to tumor invasion, metastasis and poor clinical outcome. We preliminarily found that the epidermal growth factor receptor (EGFR) is involved in enhancing the malignant potential of MDR breast cancer cells, but the mechanism remains unclear. In the present study, we demonstrated in vitro and in vivo that EGFR/HER2 promote the invasive and metastatic abilities of MDR breast cancer. More importantly, a new function of EGFR/HER2 inhibitors was revealed for the first time, which could improve the treatment efficacy of breast cancer by reversing the MDR process rather than by inhibiting tumor growth. Firstly, using quantitative real‑time PCR and western blot analysis, we found that overexpression of EGFR/HER2 in MCF7/Adr cells upregulated CD147 and MMP2/9 at both the transcription and protein expression levels, which promoted tumor cell migration, as determined using an in vitro invasion assay. Secondly, the upregulated levels of CD147 and MMP2/9 were decreased when EGFR/HER2 activity was inhibited, and therefore tumor invasion was also significantly inhibited. These phenomena were also demonstrated in nude mouse assays. Additionally, in MDR breast cancer patients, we found that overexpression of EGFR and P‑gp levels led to shorter overall survival (OS) and disease‑free survival (DFS) by IHC assays and Kaplan‑Meier survival analysis. In conclusion, EGFR/HER2 play a crucial role in enhancing CD147 and MMP expression to establish favorable conditions for invasion/metastasis in MDR breast cancer. The scope of application of EGFR/HER2 inhibitors may be expanded in EGFR/HER2‑positive patients. We suggest that MDR breast cancer patients may benefit from novel therapies targeting EGFR/HER2. PMID:26718028

  15. Expression of genes encoding extracellular matrix proteins: A macroarray study

    PubMed Central

    FUTYMA, KONRAD; MIOTŁA, PAWEŁ; RÓŻYŃSKA, KRYSTYNA; ZDUNEK, MAŁGORZATA; SEMCZUK, ANDRZEJ; RECHBERGER, TOMASZ; WOJCIEROWSKI, JACEK

    2014-01-01

    Endometrial cancer (EC) is one of the most common gynecological malignancies in Poland, with well-established risk factors. Genetic instability and molecular alterations responsible for endometrial carcinogenesis have been systematically investigated. The aim of the present study was to investigate, by means of cDNA macroarrays, the expression profiles of genes encoding extracellular matrix (ECM) proteins in ECs. Tissue specimens were collected during surgical procedures from 40 patients with EC, and control tissue was collected from 9 patients with uterine leiomyomas. RNA was isolated and RT-PCR with radioisotope-labeled cDNA was performed. The levels of ECM protein gene expression in normal endometrial tissues were compared to the expression of these genes in EC specimens. Statistically significant differences in gene expression, stratified by clinical stage of the ECs, were detected for aggrecan, vitronectin, tenascin R, nidogen and two collagen proteins: type VIII chain α1 and type XI chain α2. All of these proteins were overexpressed in stage III endometrial carcinomas compared to levels in stage I and II uterine neoplasms. In conclusion, increased expression of genes encoding ECM proteins may play an important role in facilitating accelerated disease progression of human ECs. PMID:25231141

  16. Genome engineering for improved recombinant protein expression in Escherichia coli.

    PubMed

    Mahalik, Shubhashree; Sharma, Ashish K; Mukherjee, Krishna J

    2014-01-01

    A metabolic engineering perspective which views recombinant protein expression as a multistep pathway allows us to move beyond vector design and identify the downstream rate limiting steps in expression. In E.coli these are typically at the translational level and the supply of precursors in the form of energy, amino acids and nucleotides. Further recombinant protein production triggers a global cellular stress response which feedback inhibits both growth and product formation. Countering this requires a system level analysis followed by a rational host cell engineering to sustain expression for longer time periods. Another strategy to increase protein yields could be to divert the metabolic flux away from biomass formation and towards recombinant protein production. This would require a growth stoppage mechanism which does not affect the metabolic activity of the cell or the transcriptional or translational efficiencies. Finally cells have to be designed for efficient export to prevent buildup of proteins inside the cytoplasm and also simplify downstream processing. The rational and the high throughput strategies that can be used for the construction of such improved host cell platforms for recombinant protein expression is the focus of this review. PMID:25523647

  17. Subcellular localization of transiently expressed fluorescent fusion proteins.

    PubMed

    Collings, David A

    2013-01-01

    The recent and massive expansion in plant genomics data has generated a large number of gene sequences for which two seemingly simple questions need to be answered: where do the proteins encoded by these genes localize in cells, and what do they do? One widespread approach to answering the localization question has been to use particle bombardment to transiently express unknown proteins tagged with green fluorescent protein (GFP) or its numerous derivatives. Confocal fluorescence microscopy is then used to monitor the localization of the fluorescent protein as it hitches a ride through the cell. The subcellular localization of the fusion protein, if not immediately apparent, can then be determined by comparison to localizations generated by fluorescent protein fusions to known signalling sequences and proteins, or by direct comparison with fluorescent dyes. This review aims to be a tour guide for researchers wanting to travel this hitch-hiker's path, and for reviewers and readers who wish to understand their travel reports. It will describe some of the technology available for visualizing protein localizations, and some of the experimental approaches for optimizing and confirming localizations generated by particle bombardment in onion epidermal cells, the most commonly used experimental system. As the non-conservation of signal sequences in heterologous expression systems such as onion, and consequent mis-targeting of fusion proteins, is always a potential problem, the epidermal cells of the Argenteum mutant of pea are proposed as a model system. PMID:23996319

  18. Identification of prognostic biomarkers for glioblastomas using protein expression profiling

    PubMed Central

    JUNG, YONG; JOO, KYEUNG MIN; SEONG, DONG HO; CHOI, YOON-LA; KONG, DOO-SIK; KIM, YONGHYUN; KIM, MI HYUN; JIN, JUYOUN; SUH, YEON-LIM; SEOL, HO JUN; SHIN, CHUL SOO; LEE, JUNG-IL; KIM, JONG-HYUN; SONG, SANG YONG; NAM, DO-HYUN

    2012-01-01

    A set of proteins reflecting the prognosis of patients have clinical significance since they could be utilized as predictive biomarkers and/or potential therapeutic targets. With the aim of finding novel diagnostic and prognostic markers for glioblastoma (GBM), a tissue microarray (TMA) library consisting of 62 GBMs and 28 GBM-associated normal spots was constructed. Immunohistochemistry against 78 GBM-associated proteins was performed. Expression levels of each protein for each patient were analyzed using an image analysis program and converted to H-score [summation of the intensity grade of staining (0–3) multiplied by the percentage of positive cells corresponding to each grade]. Based on H-score and hierarchical clustering methods, we divided the GBMs into two groups (n=19 and 37) that had significantly different survival lengths (p<0.05). In the two groups, expression of nine proteins (survivin, cyclin E, DCC, TGF-β, CDC25B, histone H1, p-EGFR, p-VEGFR2/3, p16) was significantly changed (q<0.05). Prognosis-predicting potential of these proteins were validated with another independent library of 82 GBM TMAs and a public GBM DNA microarray dataset. In addition, we determined 32 aberrant or mislocalized subcellular protein expression patterns in GBMs compared with relatively normal brain tissues, which could be useful for diagnostic biomarkers of GBM. We therefore suggest that these proteins can be used as predictive biomarkers and/or potential therapeutic targets for GBM. PMID:22179774

  19. Protein Co-Expression Network Analysis (ProCoNA)

    SciTech Connect

    Gibbs, David L.; Baratt, Arie; Baric, Ralph; Kawaoka, Yoshihiro; Smith, Richard D.; Orwoll, Eric S.; Katze, Michael G.; Mcweeney, Shannon K.

    2013-06-01

    Biological networks are important for elucidating disease etiology due to their ability to model complex high dimensional data and biological systems. Proteomics provides a critical data source for such models, but currently lacks robust de novo methods for network construction, which could bring important insights in systems biology. We have evaluated the construction of network models using methods derived from weighted gene co-expression network analysis (WGCNA). We show that approximately scale-free peptide networks, composed of statistically significant modules, are feasible and biologically meaningful using two mouse lung experiments and one human plasma experiment. Within each network, peptides derived from the same protein are shown to have a statistically higher topological overlap and concordance in abundance, which is potentially important for inferring protein abundance. The module representatives, called eigenpeptides, correlate significantly with biological phenotypes. Furthermore, within modules, we find significant enrichment for biological function and known interactions (gene ontology and protein-protein interactions). Biological networks are important tools in the analysis of complex systems. In this paper we evaluate the application of weighted co-expression network analysis to quantitative proteomics data. Protein co-expression networks allow novel approaches for biological interpretation, quality control, inference of protein abundance, a framework for potentially resolving degenerate peptide-protein mappings, and a biomarker signature discovery.

  20. Hedyotis diffusa Willd overcomes 5-fluorouracil resistance in human colorectal cancer HCT-8/5-FU cells by downregulating the expression of P-glycoprotein and ATP-binding casette subfamily G member 2

    PubMed Central

    LI, QIONGYU; WANG, XIANGFENG; SHEN, ALING; ZHANG, YUCHEN; CHEN, YOUQIN; SFERRA, THOMAS J.; LIN, JIUMAO; PENG, JUN

    2015-01-01

    Previous studies have demonstrated that Hedyotis diffusa Willd (HDW), a traditional Chinese herbal medicine, exhibits potent anticancer activity in models of colorectal cancer (CRC). Aggressive forms of CRC exhibit resistance to widely used chemotherapeutic drugs, including the antimetabolite, 5-fluorouracil (5-FU); however, less is known with regard to the activity of HDW against 5-FU-resistant cancer. In the present study, the mechanism of action and the potency of ethanol extracts of HDW (EEHDW) were investigated on a multidrug-resistant CRC HCT-8/5-FU cell line. Using an MTT cell proliferation assay, EEHDW treatment was shown to significantly reduce the cell viability of HCT-8/5-FU cells in a dose- and time-dependent manner. Furthermore, EEHDW significantly increased the retention of the ATP-binding cassette (ABC) transporter substrate, rhodamine-123, as compared with the untreated controls. To further investigate the molecular mechanisms targeted by EEHDW in the resistant cells, the expression levels of the ABC drug transporter protein, P-glycoprotein (P-gp), and ABC subfamily G member 2 (ABCG2), were analyzed using reverse-transcription polymerase chain reaction and western blot analysis. The mRNA and protein expression levels of P-gp and ABCG2 were reduced in the HCT-8/5-FU cells following EEHDW treatment, indicating that EEHDW inhibits ABCG2-mediated drug resistance by downregulating the expression of ABCG2 and P-gp. Therefore, the potential application of EEHDW as a chemotherapeutic adjuvant represents a promising alternative approach to the treatment of drug-resistant CRC. PMID:26640560

  1. Expression of P-glycoprotein in excised human nasal mucosa and optimized models of RPMI 2650 cells.

    PubMed

    Dolberg, Anne M; Reichl, Stephan

    2016-07-11

    To assess the transmucosal drug transport in the development of medications for intranasal administration, cellular in vitro models are preferred over the use of animal tissues due to inter-species variations and ethical concerns. With regard to the distribution of active agents and multidrug resistance, the ABC transporter P-glycoprotein plays a major role in several mammalian tissues. The present study compares the expression of this efflux pump in optimized in vitro models based on the human RPMI 2650 cell line with specimens of human turbinate mucosa. The presence of the ABCB1 gene was investigated at the mRNA and protein levels using RT-PCR and Western blot analysis in differently cultured RPMI 2650 cells and excised human nasal epithelium. Furthermore, the localization and activity of P-gp was examined by immunohistochemical staining and functionality assays using different substrates in both in vitro and ex vivo models. Both mRNA and protein expression of P-gp was found in all studied models. Furthermore, transporter functionality was detected in both RPMI 2650 cell culture models and excised human mucosa. The results demonstrated a highly promising comparability between RPMI 2650 models and explants of human nasal tissue concerning the influence of MDR1 on drug disposition. The RPMI 2650 cell line might become a useful tool in preclinical trials to improve reproducibility and achieve greater applicability to humans of experimental data regarding passive diffusion and active efflux of drug candidates. PMID:27155589

  2. Increased functional protein expression using nucleotide sequence features enriched in highly expressed genes in zebrafish

    PubMed Central

    Horstick, Eric J.; Jordan, Diana C.; Bergeron, Sadie A.; Tabor, Kathryn M.; Serpe, Mihaela; Feldman, Benjamin; Burgess, Harold A.

    2015-01-01

    Many genetic manipulations are limited by difficulty in obtaining adequate levels of protein expression. Bioinformatic and experimental studies have identified nucleotide sequence features that may increase expression, however it is difficult to assess the relative influence of these features. Zebrafish embryos are rapidly injected with calibrated doses of mRNA, enabling the effects of multiple sequence changes to be compared in vivo. Using RNAseq and microarray data, we identified a set of genes that are highly expressed in zebrafish embryos and systematically analyzed for enrichment of sequence features correlated with levels of protein expression. We then tested enriched features by embryo microinjection and functional tests of multiple protein reporters. Codon selection, releasing factor recognition sequence and specific introns and 3′ untranslated regions each increased protein expression between 1.5- and 3-fold. These results suggested principles for increasing protein yield in zebrafish through biomolecular engineering. We implemented these principles for rational gene design in software for codon selection (CodonZ) and plasmid vectors incorporating the most active non-coding elements. Rational gene design thus significantly boosts expression in zebrafish, and a similar approach will likely elevate expression in other animal models. PMID:25628360

  3. Effects of Chemically Modified Messenger RNA on Protein Expression.

    PubMed

    Li, Bin; Luo, Xiao; Dong, Yizhou

    2016-03-16

    Chemically modified nucleotides play significant roles in the effectiveness of mRNA translation. Here, we describe the synthesis of two sets of chemically modified mRNAs [encoding firefly Luciferase (FLuc) and enhanced green fluorescent protein (eGFP), respectively], evaluation of protein expression, and correlation analysis of expression level under various conditions. The results indicate that chemical modifications of mRNAs are able to significantly improve protein expression, which is dependent on cell types and coding sequences. Moreover, eGFP mRNAs with N1-methylpseudouridine (me(1)ψ), 5-methoxyuridine (5moU), and pseudouridine (ψ) modifications ranked top three in cell lines tested. Interestingly, 5moU-modified eGFP mRNA was more stable than other eGFP mRNAs. Consequently, me(1)ψ, 5moU, and ψ are promising nucleotides for chemical modification of mRNAs. PMID:26906521

  4. Using ion exchange chromatography to purify a recombinantly expressed protein.

    PubMed

    Duong-Ly, Krisna C; Gabelli, Sandra B

    2014-01-01

    Ion exchange chromatography (IEX) separates molecules by their surface charge, a property that can vary vastly between different proteins. There are two types of IEX, cation exhange and anion exchange chromatography. The protocol that follows was designed by the authors for anion exchange chromatography of a recombinantly expressed protein having a pI of 4.9 and containing two cysteine residues and one tryptophan residue, using an FPLC system. Prior to anion exchange, the protein had been salted out using ammonium sulfate precipitation and partially purified via hydrophobic interaction chromatography (see Salting out of proteins using ammonium sulfate precipitation and Use and Application of Hydrophobic Interaction Chromatography for Protein Purification). Slight modifications to this protocol may be made to accommodate both the protein of interest and the availability of equipment. PMID:24674065

  5. Recombinant baculovirus vectors expressing glutathione-S-transferase fusion proteins.

    PubMed

    Davies, A H; Jowett, J B; Jones, I M

    1993-08-01

    Recombinant baculoviruses are a popular means of producing heterologous protein in eukaryotic cells. Purification of recombinant proteins away from the insect cell background can, however, remain an obstacle for many developments. Recently, prokaryotic fusion protein expression systems have been developed allowing single-step purification of the heterologous protein and specific proteolytic cleavage of the affinity tag moiety from the desired antigen. Here we report the introduction of these attributes to the baculovirus system. "Baculo-GEX" vectors enable baculovirus production of fusion proteins with the above advantages, but in a eukaryotic post-translational processing environment. Glutathione-S-transferase (GST) fusions are stable cytoplasmic proteins in insect cells and may therefore be released by sonication alone, avoiding the solubility problems and detergent requirements of bacterial systems. Thus large amounts of authentic antigen may be purified in a single, non-denaturing step. PMID:7763917

  6. Green fluorescent protein-based expression screening of membrane proteins in Escherichia coli.

    PubMed

    Bird, Louise E; Rada, Heather; Verma, Anil; Gasper, Raphael; Birch, James; Jennions, Matthew; Lӧwe, Jan; Moraes, Isabel; Owens, Raymond J

    2015-01-01

    The production of recombinant membrane proteins for structural and functional studies remains technically challenging due to low levels of expression and the inherent instability of many membrane proteins once solubilized in detergents. A protocol is described that combines ligation independent cloning of membrane proteins as GFP fusions with expression in Escherichia coli detected by GFP fluorescence. This enables the construction and expression screening of multiple membrane protein/variants to identify candidates suitable for further investment of time and effort. The GFP reporter is used in a primary screen of expression by visualizing GFP fluorescence following SDS polyacrylamide gel electrophoresis (SDS-PAGE). Membrane proteins that show both a high expression level with minimum degradation as indicated by the absence of free GFP, are selected for a secondary screen. These constructs are scaled and a total membrane fraction prepared and solubilized in four different detergents. Following ultracentrifugation to remove detergent-insoluble material, lysates are analyzed by fluorescence detection size exclusion chromatography (FSEC). Monitoring the size exclusion profile by GFP fluorescence provides information about the mono-dispersity and integrity of the membrane proteins in different detergents. Protein: detergent combinations that elute with a symmetrical peak with little or no free GFP and minimum aggregation are candidates for subsequent purification. Using the above methodology, the heterologous expression in E. coli of SED (shape, elongation, division, and sporulation) proteins from 47 different species of bacteria was analyzed. These proteins typically have ten transmembrane domains and are essential for cell division. The results show that the production of the SEDs orthologues in E. coli was highly variable with respect to the expression levels and integrity of the GFP fusion proteins. The experiment identified a subset for further investigation. PMID

  7. Astragaloside IV reduces the expression level of P-glycoprotein in multidrug-resistant human hepatic cancer cell lines

    PubMed Central

    WANG, PEI-PEI; XU, DU-JUAN; HUANG, CAN; WANG, WEI-PING; XU, WEN-KE

    2014-01-01

    Astragaloside is a saponin widely used in traditional Chinese medicine and has been reported to be a potent multidrug resistance (MDR) reversal agent. The present study investigated the role of astragaloside IV (ASIV) in the regulation of P-glycoprotein (P-gp, encoded by the mdr1 gene) and its effect on the reversal of MDR. The activity of ASIV was evaluated using human hepatic cancer cells Bel-7402 and the corresponding 5-fluorouracil (5-FU) resistant cells Bel-7402/FU. ASIV (0.08 mg/ml) potentiated the cytotoxicity of 5-FU which was demonstrated using the MTT assay on Bel-7402/FU cells. ASIV reduced the expression of P-gp as was revealed by immunocytochemistry. Accumulation and efflux studies with the P-gp substrate, rhodamine 123 (Rh123), demonstrated that ASIV inhibited P-gp-mediated drug efflux. Furthermore, it was demonstrated that ASIV enhanced the drug accumulation of 5-FU using a high performance liquid chromatography (HPLC) assay for drug resistant cells. Furthermore, ASIV may downregulate the expression of P-gp, which was examined using western blot analysis and polymerase chain reaction. In conclusion, the results of the present study indicated that ASIV reverses the drug resistance of Bel-7402/FU cells by downregulating the expression of mdr1. ASIV may represent a potent modulator of P-gp-mediated MDR in hepatic cancer therapy. PMID:24676670

  8. Astragaloside Ⅳ reduces the expression level of P-glycoprotein in multidrug-resistant human hepatic cancer cell lines.

    PubMed

    Wang, Pei-Pei; Xu, Du-Juan; Huang, Can; Wang, Wei-Ping; Xu, Wen-Ke

    2014-06-01

    Astragaloside is a saponin widely used in traditional Chinese medicine and has been reported to be a potent multidrug resistance (MDR) reversal agent. The present study investigated the role of astragaloside Ⅳ (ASIV) in the regulation of P-glycoprotein (P-gp, encoded by the mdr1 gene) and its effect on the reversal of MDR. The activity of ASIV was evaluated using human hepatic cancer cells Bel-7402 and the corresponding 5-fluorouracil (5-FU) resistant cells Bel-7402/FU. ASIV (0.08 mg/ml) potentiated the cytotoxicity of 5-FU which was demonstrated using the MTT assay on Bel-7402/FU cells. ASIV reduced the expression of P-gp as was revealed by immunocytochemistry. Accumulation and efflux studies with the P-gp substrate, rhodamine 123 (Rh123), demonstrated that ASIV inhibited P-gp-mediated drug efflux. Furthermore, it was demonstrated that ASⅣ enhanced the drug accumulation of 5-FU using a high performance liquid chromatography (HPLC) assay for drug resistant cells. Furthermore, ASIV may downregulate the expression of P-gp, which was examined using western blot analysis and polymerase chain reaction. In conclusion, the results of the present study indicated that ASIV reverses the drug resistance of Bel-7402/FU cells by downregulating the expression of mdr1. ASIV may represent a potent modulator of P-gp-mediated MDR in hepatic cancer therapy. PMID:24676670

  9. Bovine parotid secretory protein: structure, expression and relatedness to other BPI (bactericidal/permeability-increasing protein)-like proteins.

    PubMed

    Wheeler, T T; Hood, K; Oden, K; McCracken, J; Morris, C A

    2003-08-01

    Members of the family of BPI (bactericidal/permeability-increasing protein)-like proteins are as yet incompletely characterized, particularly in cattle, where full-length sequence information is available for only three of the 13 family members known from other species. Structural bioinformatic analyses incorporating bovine homologues of several members of the BPI-like protein family, including two forms of bovine parotid secretory protein (PSP), showed that this family is also present in cattle. Expression analyses of several members of the BPI-like protein family in cattle, including PSP (Bsp30), von Ebner's minor salivary gland protein (VEMSGP) and lung-specific X protein (LUNX), showed a restricted pattern of expression, consistent with earlier hypotheses that these proteins function in the innate immune response to bacteria. The possible role of bovine PSP in susceptibility to pasture bloat in cattle is discussed. PMID:12887305

  10. Combining in Vitro Folding with Cell Free Protein Synthesis for Membrane Protein Expression.

    PubMed

    Focke, Paul J; Hein, Christopher; Hoffmann, Beate; Matulef, Kimberly; Bernhard, Frank; Dötsch, Volker; Valiyaveetil, Francis I

    2016-08-01

    Cell free protein synthesis (CFPS) has emerged as a promising methodology for protein expression. While polypeptide production is very reliable and efficient using CFPS, the correct cotranslational folding of membrane proteins during CFPS is still a challenge. In this contribution, we describe a two-step protocol in which the integral membrane protein is initially expressed by CFPS as a precipitate followed by an in vitro folding procedure using lipid vesicles for converting the protein precipitate to the correctly folded protein. We demonstrate the feasibility of using this approach for the K(+) channels KcsA and MVP and the amino acid transporter LeuT. We determine the crystal structure of the KcsA channel obtained by CFPS and in vitro folding to show the structural similarity to the cellular expressed KcsA channel and to establish the feasibility of using this two-step approach for membrane protein production for structural studies. Our studies show that the correct folding of these membrane proteins with complex topologies can take place in vitro without the involvement of the cellular machinery for membrane protein biogenesis. This indicates that the folding instructions for these complex membrane proteins are contained entirely within the protein sequence. PMID:27384110

  11. Relationship between P-glycoprotein expression and cyclosporin A in kidney. An immunohistological and cell culture study.

    PubMed Central

    García del Moral, R.; O'Valle, F.; Andújar, M.; Aguilar, M.; Lucena, M. A.; López-Hidalgo, J.; Ramírez, C.; Medina-Cano, M. T.; Aguilar, D.; Gómez-Morales, M.

    1995-01-01

    P-glycoprotein (P-gp), encoded in humans by the mdr-1 gene, acts physiologically as an efflux pump to expel hydrophobic substances from cells. This glycoprotein is closely related to multidrug resistance in tumor cells and can be modulated by cyclosporin A (CsA). We investigated the relationship between CsA and P-gp in 52 renal allograft biopsies and in cultures of Madin-Darby canine kidney (MDCK) renal tubule cells to determine whether the intrarenal accumulation of CsA or chronic stimulation with the drug modified the expression of P-gp. Expression of P-gp and CsA was analyzed by immunohistochemistry. Immunostaining was evaluated semiquantitatively. Modulation of P-gp in MDCK cells after chronic stimulation with CsA for 7, 30, and 60 days was analyzed by flow cytometry. P-gp and CsA immunostaining in renal post-transplant biopsies showed considerable overlap in all cases (Spearman's test, r = 0.577, P < 0.001). After 7 days in vitro, the number of cells expressing P-gp increased progressively; a further increase in mean fluorescence was found after 60 days (P < 0.001, Student's t-test). Our findings suggest that in non-neoplastic cells, CsA may stimulate P-gp as a mechanism of detoxification. Individual differences in the adaptive responses to glycoprotein may be responsible for the appearance of nephrotoxicity or a CsA-resistant rejection reaction in cases of overexpression on lymphocytes and macrophages. Images Figure 1 PMID:7856751

  12. p53 AND MDM2 PROTEIN EXPRESSION IN ACTINIC CHEILITIS

    PubMed Central

    de Freitas, Maria da Conceição Andrade; Ramalho, Luciana Maria Pedreira; Xavier, Flávia Caló Aquino; Moreira, André Luis Gomes; Reis, Sílvia Regina Almeida

    2008-01-01

    Actinic cheilitis is a potentially malignant lip lesion caused by excessive and prolonged exposure to ultraviolet radiation, which can lead to histomorphological alterations indicative of abnormal cell differentiation. In this pathology, varying degrees of epithelial dysplasia may be found. There are few published studies regarding the p53 and MDM2 proteins in actinic cheilitis. Fifty-eight cases diagnosed with actinic cheilitis were histologically evaluated using Banóczy and Csiba (1976) parameters, and were subjected to immunohistochemical analysis using the streptavidin-biotin method in order to assess p53 and MDM2 protein expression. All studied cases expressed p53 proteins in basal and suprabasal layers. In the basal layer, the nuclei testing positive for p53 were stained intensely, while in the suprabasal layer, cells with slightly stained nuclei were predominant. All cases also tested positive for the MDM2 protein, but with varying degrees of nuclear expression and a predominance of slightly stained cells. A statistically significant correlation between the percentage of p53 and MDM2-positive cells was established, regardless of the degree of epithelial dysplasia. The expression of p53 and MDM2 proteins in actinic cheilitis can be an important indicator in lip carcinogenesis, regardless of the degree of epithelial dysplasia. PMID:19082401

  13. Beyond protein expression, MOPED goes multi-omics.

    PubMed

    Montague, Elizabeth; Janko, Imre; Stanberry, Larissa; Lee, Elaine; Choiniere, John; Anderson, Nathaniel; Stewart, Elizabeth; Broomall, William; Higdon, Roger; Kolker, Natali; Kolker, Eugene

    2015-01-01

    MOPED (Multi-Omics Profiling Expression Database; http://moped.proteinspire.org) has transitioned from solely a protein expression database to a multi-omics resource for human and model organisms. Through a web-based interface, MOPED presents consistently processed data for gene, protein and pathway expression. To improve data quality, consistency and use, MOPED includes metadata detailing experimental design and analysis methods. The multi-omics data are integrated through direct links between genes and proteins and further connected to pathways and experiments. MOPED now contains over 5 million records, information for approximately 75,000 genes and 50,000 proteins from four organisms (human, mouse, worm, yeast). These records correspond to 670 unique combinations of experiment, condition, localization and tissue. MOPED includes the following new features: pathway expression, Pathway Details pages, experimental metadata checklists, experiment summary statistics and more advanced searching tools. Advanced searching enables querying for genes, proteins, experiments, pathways and keywords of interest. The system is enhanced with visualizations for comparing across different data types. In the future MOPED will expand the number of organisms, increase integration with pathways and provide connections to disease. PMID:25404128

  14. Interfacial polymerization for colorimetric labeling of protein expression in cells.

    PubMed

    Lilly, Jacob L; Sheldon, Phillip R; Hoversten, Liv J; Romero, Gabriela; Balasubramaniam, Vivek; Berron, Brad J

    2014-01-01

    Determining the location of rare proteins in cells typically requires the use of on-sample amplification. Antibody based recognition and enzymatic amplification is used to produce large amounts of visible label at the site of protein expression, but these techniques suffer from the presence of nonspecific reactivity in the biological sample and from poor spatial control over the label. Polymerization based amplification is a recently developed alternative means of creating an on-sample amplification for fluorescence applications, while not suffering from endogenous labels or loss of signal localization. This manuscript builds upon polymerization based amplification by developing a stable, archivable, and colorimetric mode of amplification termed Polymer Dye Labeling. The basic concept involves an interfacial polymer grown at the site of protein expression and subsequent staining of this polymer with an appropriate dye. The dyes Evans Blue and eosin were initially investigated for colorimetric response in a microarray setting, where both specifically stained polymer films on glass. The process was translated to the staining of protein expression in human dermal fibroblast cells, and Polymer Dye Labeling was specific to regions consistent with desired protein expression. The labeling is stable for over 200 days in ambient conditions and is also compatible with modern mounting medium. PMID:25536421

  15. Interfacial Polymerization for Colorimetric Labeling of Protein Expression in Cells

    PubMed Central

    Lilly, Jacob L.; Sheldon, Phillip R.; Hoversten, Liv J.; Romero, Gabriela; Balasubramaniam, Vivek; Berron, Brad J.

    2014-01-01

    Determining the location of rare proteins in cells typically requires the use of on-sample amplification. Antibody based recognition and enzymatic amplification is used to produce large amounts of visible label at the site of protein expression, but these techniques suffer from the presence of nonspecific reactivity in the biological sample and from poor spatial control over the label. Polymerization based amplification is a recently developed alternative means of creating an on-sample amplification for fluorescence applications, while not suffering from endogenous labels or loss of signal localization. This manuscript builds upon polymerization based amplification by developing a stable, archivable, and colorimetric mode of amplification termed Polymer Dye Labeling. The basic concept involves an interfacial polymer grown at the site of protein expression and subsequent staining of this polymer with an appropriate dye. The dyes Evans Blue and eosin were initially investigated for colorimetric response in a microarray setting, where both specifically stained polymer films on glass. The process was translated to the staining of protein expression in human dermal fibroblast cells, and Polymer Dye Labeling was specific to regions consistent with desired protein expression. The labeling is stable for over 200 days in ambient conditions and is also compatible with modern mounting medium. PMID:25536421

  16. Argonaute Family Protein Expression in Normal Tissue and Cancer Entities

    PubMed Central

    Bruckmann, Astrid; Hauptmann, Judith; Deutzmann, Rainer; Meister, Gunter; Bosserhoff, Anja Katrin

    2016-01-01

    The members of the Argonaute (AGO) protein family are key players in miRNA-guided gene silencing. They enable the interaction between small RNAs and their respective target mRNA(s) and support the catalytic destruction of the gene transcript or recruit additional proteins for downstream gene silencing. The human AGO family consists of four AGO proteins (AGO1-AGO4), but only AGO2 harbors nuclease activity. In this study, we characterized the expression of the four AGO proteins in cancer cell lines and normal tissues with a new mass spectrometry approach called AGO-APP (AGO Affinity Purification by Peptides). In all analyzed normal tissues, AGO1 and AGO2 were most prominent, but marked tissue-specific differences were identified. Furthermore, considerable changes during development were observed by comparing fetal and adult tissues. We also identified decreased overall AGO expression in melanoma derived cell lines compared to other tumor cell lines and normal tissues, with the largest differences in AGO2 expression. The experiments described in this study suggest that reduced amounts of AGO proteins, as key players in miRNA processing, have impact on several cellular processes. Deregulated miRNA expression has been attributed to chromosomal aberrations, promoter regulation and it is known to have a major impact on tumor development and progression. Our findings will further increase our basic understanding of the molecular basis of miRNA processing and its relevance for disease. PMID:27518285

  17. Beyond protein expression, MOPED goes multi-omics

    PubMed Central

    Montague, Elizabeth; Janko, Imre; Stanberry, Larissa; Lee, Elaine; Choiniere, John; Anderson, Nathaniel; Stewart, Elizabeth; Broomall, William; Higdon, Roger; Kolker, Natali; Kolker, Eugene

    2015-01-01

    MOPED (Multi-Omics Profiling Expression Database; http://moped.proteinspire.org) has transitioned from solely a protein expression database to a multi-omics resource for human and model organisms. Through a web-based interface, MOPED presents consistently processed data for gene, protein and pathway expression. To improve data quality, consistency and use, MOPED includes metadata detailing experimental design and analysis methods. The multi-omics data are integrated through direct links between genes and proteins and further connected to pathways and experiments. MOPED now contains over 5 million records, information for approximately 75 000 genes and 50 000 proteins from four organisms (human, mouse, worm, yeast). These records correspond to 670 unique combinations of experiment, condition, localization and tissue. MOPED includes the following new features: pathway expression, Pathway Details pages, experimental metadata checklists, experiment summary statistics and more advanced searching tools. Advanced searching enables querying for genes, proteins, experiments, pathways and keywords of interest. The system is enhanced with visualizations for comparing across different data types. In the future MOPED will expand the number of organisms, increase integration with pathways and provide connections to disease. PMID:25404128

  18. Argonaute Family Protein Expression in Normal Tissue and Cancer Entities.

    PubMed

    Völler, Daniel; Linck, Lisa; Bruckmann, Astrid; Hauptmann, Judith; Deutzmann, Rainer; Meister, Gunter; Bosserhoff, Anja Katrin

    2016-01-01

    The members of the Argonaute (AGO) protein family are key players in miRNA-guided gene silencing. They enable the interaction between small RNAs and their respective target mRNA(s) and support the catalytic destruction of the gene transcript or recruit additional proteins for downstream gene silencing. The human AGO family consists of four AGO proteins (AGO1-AGO4), but only AGO2 harbors nuclease activity. In this study, we characterized the expression of the four AGO proteins in cancer cell lines and normal tissues with a new mass spectrometry approach called AGO-APP (AGO Affinity Purification by Peptides). In all analyzed normal tissues, AGO1 and AGO2 were most prominent, but marked tissue-specific differences were identified. Furthermore, considerable changes during development were observed by comparing fetal and adult tissues. We also identified decreased overall AGO expression in melanoma derived cell lines compared to other tumor cell lines and normal tissues, with the largest differences in AGO2 expression. The experiments described in this study suggest that reduced amounts of AGO proteins, as key players in miRNA processing, have impact on several cellular processes. Deregulated miRNA expression has been attributed to chromosomal aberrations, promoter regulation and it is known to have a major impact on tumor development and progression. Our findings will further increase our basic understanding of the molecular basis of miRNA processing and its relevance for disease. PMID:27518285

  19. The Expression and Significance of Neuronal Iconic Proteins in Podocytes

    PubMed Central

    Sun, Yu; Zhang, Hongxia; Hu, Ruimin; Sun, Jianyong; Mao, Xing; Zhao, Zhonghua; Chen, Qi; Zhang, Zhigang

    2014-01-01

    Growing evidence suggests that there are many common cell biological features shared by neurons and podocytes; however, the mechanism of podocyte foot process formation remains unclear. Comparing the mechanisms of process formation between two cell types should provide useful guidance from the progress of neuron research. Studies have shown that some mature proteins of podocytes, such as podocin, nephrin, and synaptopodin, were also expressed in neurons. In this study, using cell biological experiments and immunohistochemical techniques, we showed that some neuronal iconic molecules, such as Neuron-specific enolase, nestin and Neuron-specific nuclear protein, were also expressed in podocytes. We further inhibited the expression of Neuron-specific enolase, nestin, synaptopodin and Ubiquitin carboxy terminal hydrolase-1 by Small interfering RNA in cultured mouse podocytes and observed the significant morphological changes in treated podocytes. When podocytes were treated with Adriamycin, the protein expression of Neuron-specific enolase, nestin, synaptopodin and Ubiquitin carboxy terminal hydrolase-1 decreased over time. Meanwhile, the morphological changes in the podocytes were consistent with results of the Small interfering RNA treatment of these proteins. The data demonstrated that neuronal iconic proteins play important roles in maintaining and regulating the formation and function of podocyte processes. PMID:24699703

  20. Expression of bone matrix proteins in urolithiasis model rats.

    PubMed

    Yasui, T; Fujita, K; Sasaki, S; Sato, M; Sugimoto, M; Hirota, S; Kitamura, Y; Nomura, S; Kohri, K

    1999-08-01

    Urinary calcium stones are a pathological substance, and they show similarities to physiological mineralization and other pathological mineralizations. The expression of messenger (m) RNAs of osteopontin (OPN), matrix Gla protein (MGP), osteonectin (ON) and osteocalcin (OC) in bones and teeth has been described. We previously identified OPN as an important stone matrix protein. In addition, the spontaneous calcification of arteries and cartilage in mice lacking MGP was recently reported, a finding which indicates that MGP has a function as an inhibitor of mineralization. Here, we examined the mRNA expressions of OPN, MGP, ON, and OC in the kidneys of stone-forming model rats administered an oxalate precursor, ethylene glycol (EG) for up to 28 days. The Northern blotting showed that the mRNA expressions of OPN and MGP were markedly increased with the administration of EG, but their expression patterns differed. The OPN mRNA expression reached the maximal level at day 7 after the initiation of the EG treatment and showed no significant difference after 14 and 28 days, whereas the MGP mRNA expression rose gradually to day 28. The in situ hybridization demonstrated that the cell type expressing OPN mRNA was different from that expressing MGP. We suggest that OPN acts on calcification and MGP acts on suppression. PMID:10460895

  1. hTERT protein expression is independent of clinicopathological parameters and c-Myc protein expression in human breast cancer

    PubMed Central

    Elkak, AE; Meligonis, G; Salhab, M; Mitchell, B; Blake, JRS; Newbold, RF; Mokbel, K

    2005-01-01

    Background Telomerase is a ribonucleoprotein enzyme that synthesises telomeres after cell division and maintains chromosomal length and stability thus leading to cellular immortalisation. The hTERT (human telomerase reverse transcriptase) subunit seems to be the rate-limiting determinant of telomerase and knowledge of factors controlling hTERT transcription may be useful in therapeutic strategies. The hTERT promoter contains binding sites for c-Myc and there is some experimental and in vitro evidence that c-Myc may increase hTERT expression. We previously reported no correlation between c-Myc mRNA expression and hTERT mRNA or telomerase activity in human breast cancer. This study aims to examine the correlation between hTERT expression as determined by immunohistochemistry and c-Myc expression, lymph node status, and tumour size and grade in human breast cancer. Materials and methods The immunohistochemical expression of hTERT and c-Myc was investigated in 38 malignant breast tumours. The expression of hTERT was then correlated with the lymph node status, c-Myc expression and other clinicopathological parameters of the tumours. Results hTERT expression was positive in 27 (71%) of the 38 tumours. 15 (79%) of 19 node positive tumours were hTERT positive compared with 11 (63%) of 19 node negative tumours. The expression was higher in node positive tumours but this failed to reach statistical significance (p = 0.388). There was no significant association with tumour size, tumour grade or c-Myc expression. However, hTERT expression correlated positively with patients' age (correlation coefficient = 0.415, p = 0.0097). Conclusion hTERT protein expression is independent of lymph node status, tumour size and grade and c-Myc protein expression in human breast cancer PMID:16202165

  2. Human Cementum Protein 1 induces expression of bone and cementum proteins by human gingival fibroblasts

    SciTech Connect

    Carmona-Rodriguez, Bruno; Alvarez-Perez, Marco Antonio; Narayanan, A. Sampath; Zeichner-David, Margarita; Reyes-Gasga, Jose; Molina-Guarneros, Juan; Garcia-Hernandez, Ana Lilia; Suarez-Franco, Jose Luis; Chavarria, Ivet Gil; Villarreal-Ramirez, Eduardo; Arzate, Higinio . E-mail: harzate@servidor.unam.mx

    2007-07-06

    We recently presented evidence showing that a human cementoblastoma-derived protein, named Cementum Protein 1 (CEMP1) may play a role as a local regulator of cementoblast differentiation and cementum-matrix mineralization. This protein was shown to be expressed by cementoblasts and progenitor cells localized in the periodontal ligament. In this study we demonstrate that transfection of CEMP1 into human gingival fibroblasts (HGF) induces mineralization and expression of bone and cementum-matrix proteins. The transfected HGF cells had higher alkaline phosphatase activity and proliferation rate and they expressed genes for alkaline phosphatase, bone sialoprotein, osteocalcin, osteopontin, the transcription factor Runx2/Cbfa1, and cementum attachment protein (CAP). They also produced biological-type hydroxyapatite. These findings indicate that the CEMP1 might participate in differentiation and mineralization of nonosteogenic cells, and that it might have a potential function in cementum and bone formation.

  3. Expression of Yes Associated Protein, YAP, Modulates Survivin Expression in Primary Liver Malignancies

    PubMed Central

    Bai, Haibo; Gayyed, Mariana F.; Lam-Himlin, Dora M.; Klein, Alison P.; Nayar, Suresh K.; Xu, Yang; Khan, Mehtab; Argani, Pedram; Pan, Duojia; Anders, Robert A.

    2012-01-01

    Hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC) account for 95% of primary liver cancer. For each of these malignancies the outcome is dismal; incidence is rapidly increasing and mechanistic understanding is limited. We observed abnormal proliferation of both biliary epithelium and hepatocytes in mice following genetic manipulation of Yes associated protein (YAP), a transcription co-activator. Here we comprehensively documented YAP protein expression in the human liver and primary liver cancers. We showed that nuclear YAP expression is significantly increased in human ICC and HCC. We found that increased YAP protein levels in HCC are due to multiple mechanisms including gene amplification, transcriptional and posttranscriptional regulation. Survivin, a member of the inhibitors-of-apoptosis protein (IAPs) family, has been reported as an independent prognostic factor for poor survival in both HCC and ICC. We found nuclear YAP expression correlates significantly with nuclear Survivin expression for both ICC and HCC. Furthermore, using mice engineered to conditionally overexpress YAP in the liver, we found Survivin mRNA expression depends upon YAP protein levels. Our findings suggested that YAP contributes to primary liver tumorigenesis and likely mediates its oncogenic effects through modulating Survivin expression. PMID:22436626

  4. Over-producing soluble protein complex and validating protein-protein interaction through a new bacterial co-expression system.

    PubMed

    Zeng, Jumei; Zhang, Lei; Li, Yuqing; Wang, Yi; Wang, Mingchao; Duan, Xin; He, Zheng-Guo

    2010-01-01

    Many proteins exert their functions through a protein complex and protein-protein interactions. However, the study of these types of interactions is complicated when dealing with toxic or hydrophobic proteins. It is difficult to use the popular Escherichia coli host for their expression, as these proteins in all likelihood require a critical partner protein to ensure their proper folding and stability. In the present study, we have developed a novel co-expression vector, pHEX, which is compatible with, and thus can be partnered with, many commercially available E. coli vectors, such as pET, pGEX and pMAL. The pHEX contains the p15A origin of replication and a T7 promoter, which can over-produce a His-tagged recombinant protein. The new co-expression system was demonstrated to efficiently co-produce and co-purify heterodimeric protein complexes, for example PE25/PPE41 (Rv2430c/Rv2431c) and ESAT6/CFP10 (Rv3874/Rv3875), from the human pathogen Mycobacterium tuberculosis H37Rv. Furthermore, the system was also effectively used to characterize protein-protein interactions through convenient affinity tags. Using an in vivo pull-down assay, for the first time we have confirmed the presence of three pairs of PE/PPE-related novel protein interactions in this pathogen. In summary, a convenient and efficient co-expression vector system has been successfully developed. The new system should be applicable to any protein complex or any protein-protein interaction of interest in a wide range of biological organisms. PMID:19747546

  5. P-glycoprotein expression in normal and reactive bone marrows.

    PubMed Central

    Hegewisch-Becker, S.; Fliegner, M.; Tsuruo, T.; Zander, A.; Zeller, W.; Hossfeld, D. K.

    1993-01-01

    The expression of mdr1 gene product P-glycoprotein (P-gp) was investigated in 53 normal and reactive bone marrows by means of immunocytochemistry, using the monoclonal antibody (mAb) C219 and the alkaline phosphatase anti-alkaline phosphatase method. In a limited number of patients, data were confirmed by using the mAb MRK16 or a polymerase chain reaction assay for mdr1 gene expression. There was no history of prior chemotherapy or any malignancy in this group. Bone marrow aspirates were obtained as part of a routine diagnostic programme in bone marrow donors or in patients presenting with a variety of diagnoses such as unexplained gammopathy, fever, anaemia, other changes in peripheral blood smear, rheumatoid arthritis, vasculitis, or urticaria pigmentosa. Morphologically the bone marrow was normal in 23 patients, a megaloblastic erythropoiesis was seen in two patients and unspecific changes were seen in 28 patients. Twenty-seven of 53 samples were found to be positive for P-gp expression with the percentage of positive cells ranging from 2%-80% (mean = 24%). With a cutoff point of 10%, five of 23 normal (22%) and 13 of 28 reactive bone marrows (46%) were considered positive for P-gp expression. There was no obvious correlation between diagnosis or age and P-gp expression. Additional staining for the early surface marker CD-34 was performed in 12 samples, with none of them revealing more than 1% positivity. Since P-gp expression has so far been described only in CD-34 positive bone marrow cells, data suggest that P-gp expression may be reinduced in CD-34 negative cells under conditions which remain to be determined. Images Figure 1 Figure 2 PMID:8094974

  6. The protein expression landscape of the Arabidopsis root

    PubMed Central

    Petricka, Jalean J.; Schauer, Monica A.; Megraw, Molly; Breakfield, Natalie W.; Thompson, J. Will; Georgiev, Stoyan; Soderblom, Erik J.; Ohler, Uwe; Moseley, Martin Arthur; Grossniklaus, Ueli; Benfey, Philip N.

    2012-01-01

    Because proteins are the major functional components of cells, knowledge of their cellular localization is crucial to gaining an understanding of the biology of multicellular organisms. We have generated a protein expression map of the Arabidopsis root providing the identity and cell type-specific localization of nearly 2,000 proteins. Grouping proteins into functional categories revealed unique cellular functions and identified cell type-specific biomarkers. Cellular colocalization provided support for numerous protein–protein interactions. With a binary comparison, we found that RNA and protein expression profiles are weakly correlated. We then performed peak integration at cell type-specific resolution and found an improved correlation with transcriptome data using continuous values. We performed GeLC-MS/MS (in-gel tryptic digestion followed by liquid chromatography-tandem mass spectrometry) proteomic experiments on mutants with ectopic and no root hairs, providing complementary proteomic data. Finally, among our root hair-specific proteins we identified two unique regulators of root hair development. PMID:22447775

  7. Fragile X mental retardation protein (FMRP) interacting proteins exhibit different expression patterns during development.

    PubMed

    Bonaccorso, C M; Spatuzza, M; Di Marco, B; Gloria, A; Barrancotto, G; Cupo, A; Musumeci, S A; D'Antoni, S; Bardoni, B; Catania, M V

    2015-05-01

    Fragile X syndrome is caused by the lack of expression of fragile X mental retardation protein (FMRP), an RNA-binding protein involved in mRNA transport and translation. FMRP is a component of mRNA ribonucleoprotein complexes and it can interact with a range of proteins either directly or indirectly, as demonstrated by two-hybrid selection and co-immunoprecipitation, respectively. Most of FMRP-interacting proteins are RNA-binding proteins such as FXR1P, FXR2P and 82-FIP. Interestingly, FMRP can also interact directly with the cytoplasmic proteins CYFIP1 and CYFIP2, which do not bind RNA and link FMRP to the RhoGTPase pathway. The interaction with these different proteins may modulate the functions of FMRP by influencing its affinity to RNA and by affecting the FMRP ability of cytoskeleton remodeling through Rho/Rac GTPases. To better define the relationship of FMRP with its interacting proteins during brain development, we have analyzed the expression pattern of FMRP and its interacting proteins in the cortex, striatum, hippocampus and cerebellum at different ages in wild type (WT) mice. FMRP and FXR2P were strongly expressed during the first week and gradually decreased thereafter, more rapidly in the cerebellum than in the cortex. FXR1P was also expressed early and showed a reduction at later stages of development with a similar developmental pattern in these two regions. CYFIP1 was expressed at all ages and peaked in the third post-natal week. In contrast, CYFIP2 and 82-FIP (only in forebrain regions) were moderately expressed at P3 and gradually increased after P7. In general, the expression pattern of each protein was similar in the regions examined, except for 82-FIP, which exhibited a strong expression at P3 and low levels at later developmental stages in the cerebellum. Our data indicate that FMRP and its interacting proteins have distinct developmental patterns of expression and suggest that FMRP may be preferentially associated to certain proteins in

  8. Expression of extracellular matrix proteins in adenomatoid odontogenic tumor.

    PubMed

    Modolo, Filipe; Biz, Michelle Tillmann; Martins, Marília Trierveiller; Machado de Sousa, Suzana Orsini; de Araújo, Ney Soares

    2010-03-01

    Altered expression of extracellular matrix (ECM) components has been reported in several pathologies; however, few ECM proteins have been evaluated in adenomatoid odontogenic tumor (AOT). The aim of this study was to analyze the expression and distribution of the ECM proteoglycans: biglycan and decorin; and glycoproteins: osteonectin, osteopontin, bone sialoprotein and osteocalcin in the AOT. Three-micrometer sections from paraffin-embedded specimens were evaluated employing a streptavidin-biotin immunohistochemical method with the antibodies against the proteins previously cited. Only the osteonectin was expressed in the epithelial cells. The eosinophilic amorphous material and the connective tissue showed expression of all components studied. The calcification foci expressed only osteopontin. In conclusion, the low expression of the components studied in neoplastic epithelial cells suggests that the epithelial cells act probably as stimulators of the expression by the stroma, which in turn can act as agonist or antagonist of the tumor growth. These results suggest that the components studied probably have a key role in the biological behavior of the AOT. PMID:20070486

  9. PROTEIN EXPRESSION AND SECRETION BY TRICHODERMA REESEI UNDER LOW ENDOGENOUS PROTEIN BACKGROUND

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Trichoderma reesei (Hypocrea jecorina) is one of the most commonly used fungi for the manufacturing of industrial enzyme products. The fungus is capable of secreting proteins in levels up to 100 grams per liter. A number of homologous and heterologous proteins have been successfully over-expressed...

  10. Using Green and Red Fluorescent Proteins to Teach Protein Expression, Purification, and Crystallization

    ERIC Educational Resources Information Center

    Wu, Yifeng; Zhou, Yangbin; Song, Jiaping; Hu, Xiaojian; Ding, Yu; Zhang, Zhihong

    2008-01-01

    We have designed a laboratory curriculum using the green and red fluorescent proteins (GFP and RFP) to visualize the cloning, expression, chromatography purification, crystallization, and protease-cleavage experiments of protein science. The EGFP and DsRed monomer (mDsRed)-coding sequences were amplified by PCR and cloned into pMAL (MBP-EGFP) or…

  11. Methods and constructs for expression of foreign proteins in photosynthetic organisms

    DOEpatents

    Laible, Philip D.; Hanson, Deborah K.

    2002-01-01

    A method for expressing and purifying foreign proteins in photosynthetic organisms comprising the simultaneous expression of both the heterologous protein and a means for compartmentalizing or sequestering of the protein.

  12. Controlling for Gene Expression Changes in Transcription Factor Protein Networks*

    PubMed Central

    Banks, Charles A. S.; Lee, Zachary T.; Boanca, Gina; Lakshminarasimhan, Mahadevan; Groppe, Brad D.; Wen, Zhihui; Hattem, Gaye L.; Seidel, Chris W.; Florens, Laurence; Washburn, Michael P.

    2014-01-01

    The development of affinity purification technologies combined with mass spectrometric analysis of purified protein mixtures has been used both to identify new protein–protein interactions and to define the subunit composition of protein complexes. Transcription factor protein interactions, however, have not been systematically analyzed using these approaches. Here, we investigated whether ectopic expression of an affinity tagged transcription factor as bait in affinity purification mass spectrometry experiments perturbs gene expression in cells, resulting in the false positive identification of bait-associated proteins when typical experimental controls are used. Using quantitative proteomics and RNA sequencing, we determined that the increase in the abundance of a set of proteins caused by overexpression of the transcription factor RelA is not sufficient for these proteins to then co-purify non-specifically and be misidentified as bait-associated proteins. Therefore, typical controls should be sufficient, and a number of different baits can be compared with a common set of controls. This is of practical interest when identifying bait interactors from a large number of different baits. As expected, we found several known RelA interactors enriched in our RelA purifications (NFκB1, NFκB2, Rel, RelB, IκBα, IκBβ, and IκBε). We also found several proteins not previously described in association with RelA, including the small mitochondrial chaperone Tim13. Using a variety of biochemical approaches, we further investigated the nature of the association between Tim13 and NFκB family transcription factors. This work therefore provides a conceptual and experimental framework for analyzing transcription factor protein interactions. PMID:24722732

  13. Cementum attachment protein/protein-tyrosine phosphotase-like member A is not expressed in teeth.

    PubMed

    Schild, Christof; Beyeler, Michael; Lang, Niklaus P; Trueb, Beat

    2009-02-01

    Cementum is a highly specialized connective tissue that covers tooth roots. The only cementum-specific protein described to date is the cementum attachment protein (CAP). A putative sequence for CAP was established from a cDNA clone isolated from a human cementifying fibroma cDNA library. This sequence overlaps with a phosphatase-like protein in muscle termed the protein-tyrosine phosphatase-like member A (PTPLA). To clarify the nature of CAP/PTPLA, we cloned the homologous rat protein and determined its sequence. The rat protein shared 94% sequence identity with the human protein. On Northern blots containing RNA from various rat tissues of different developmental stages, the cDNA hybridized to an mRNA expressed in heart and skeletal muscle but not in teeth. These results were confirmed by real-time PCR. Thus, the sequence deposited in public databanks under the name 'cementum attachment protein' does not represent genuine CAP. PMID:19148556

  14. Computational codon optimization of synthetic gene for protein expression

    PubMed Central

    2012-01-01

    Background The construction of customized nucleic acid sequences allows us to have greater flexibility in gene design for recombinant protein expression. Among the various parameters considered for such DNA sequence design, individual codon usage (ICU) has been implicated as one of the most crucial factors affecting mRNA translational efficiency. However, previous works have also reported the significant influence of codon pair usage, also known as codon context (CC), on the level of protein expression. Results In this study, we have developed novel computational procedures for evaluating the relative importance of optimizing ICU and CC for enhancing protein expression. By formulating appropriate mathematical expressions to quantify the ICU and CC fitness of a coding sequence, optimization procedures based on genetic algorithm were employed to maximize its ICU and/or CC fitness. Surprisingly, the in silico validation of the resultant optimized DNA sequences for Escherichia coli, Lactococcus lactis, Pichia pastoris and Saccharomyces cerevisiae suggests that CC is a more relevant design criterion than the commonly considered ICU. Conclusions The proposed CC optimization framework can complement and enhance the capabilities of current gene design tools, with potential applications to heterologous protein production and even vaccine development in synthetic biotechnology. PMID:23083100

  15. Expression and Characterization of Recombinant Campylobacter jejuni Chemotactic Proteins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Expression and Characterization of Recombinant Campylobacter jejuni Chemotactic Proteins Hung-Yueh Yeh*, Kelli L. Hiett, John E. Line, Brian B. Oakley and Bruce S. Seal, Poultry Microbiological Safety Research Unit, Richard B. Russell Agricultural Research Center, Agricultural Research Service, Uni...

  16. Heterologous Expression of Membrane Proteins: Choosing the Appropriate Host

    PubMed Central

    Pochon, Nathalie; Dementin, Sébastien; Hivin, Patrick; Boutigny, Sylvain; Rioux, Jean-Baptiste; Salvi, Daniel; Seigneurin-Berny, Daphné; Richaud, Pierre; Joyard, Jacques; Pignol, David; Sabaty, Monique; Desnos, Thierry; Pebay-Peyroula, Eva; Darrouzet, Elisabeth; Vernet, Thierry; Rolland, Norbert

    2011-01-01

    Background Membrane proteins are the targets of 50% of drugs, although they only represent 1% of total cellular proteins. The first major bottleneck on the route to their functional and structural characterisation is their overexpression; and simply choosing the right system can involve many months of trial and error. This work is intended as a guide to where to start when faced with heterologous expression of a membrane protein. Methodology/Principal Findings The expression of 20 membrane proteins, both peripheral and integral, in three prokaryotic (E. coli, L. lactis, R. sphaeroides) and three eukaryotic (A. thaliana, N. benthamiana, Sf9 insect cells) hosts was tested. The proteins tested were of various origins (bacteria, plants and mammals), functions (transporters, receptors, enzymes) and topologies (between 0 and 13 transmembrane segments). The Gateway system was used to clone all 20 genes into appropriate vectors for the hosts to be tested. Culture conditions were optimised for each host, and specific strategies were tested, such as the use of Mistic fusions in E. coli. 17 of the 20 proteins were produced at adequate yields for functional and, in some cases, structural studies. We have formulated general recommendations to assist with choosing an appropriate system based on our observations of protein behaviour in the different hosts. Conclusions/Significance Most of the methods presented here can be quite easily implemented in other laboratories. The results highlight certain factors that should be considered when selecting an expression host. The decision aide provided should help both newcomers and old-hands to select the best system for their favourite membrane protein. PMID:22216205

  17. Escherichia coli Protein Expression System for Acetylcholine Binding Proteins (AChBPs)

    PubMed Central

    Abraham, Nikita; Paul, Blessy; Ragnarsson, Lotten; Lewis, Richard J.

    2016-01-01

    Nicotinic acetylcholine receptors (nAChR) are ligand gated ion channels, identified as therapeutic targets for a range of human diseases. Drug design for nAChR related disorders is increasingly using structure-based approaches. Many of these structural insights for therapeutic lead development have been obtained from co-crystal structures of nAChR agonists and antagonists with the acetylcholine binding protein (AChBP). AChBP is a water soluble, structural and functional homolog of the extracellular, ligand-binding domain of nAChRs. Currently, AChBPs are recombinantly expressed in eukaryotic expression systems for structural and biophysical studies. Here, we report the establishment of an Escherichia coli (E. coli) expression system that significantly reduces the cost and time of production compared to the existing expression systems. E. coli can efficiently express unglycosylated AChBP for crystallography and makes the expression of isotopically labelled forms feasible for NMR. We used a pHUE vector containing an N-terminal His-tagged ubiquitin fusion protein to facilitate AChBP expression in the soluble fractions, and thus avoid the need to recover protein from inclusion bodies. The purified protein yield obtained from the E. coli expression system is comparable to that obtained from existing AChBP expression systems. E. coli expressed AChBP bound nAChR agonists and antagonists with affinities matching those previously reported. Thus, the E. coli expression system significantly simplifies the expression and purification of functional AChBP for structural and biophysical studies. PMID:27304486

  18. Optimization of Translation Profiles Enhances Protein Expression and Solubility

    PubMed Central

    Hess, Anne-Katrin; Saffert, Paul; Liebeton, Klaus; Ignatova, Zoya

    2015-01-01

    mRNA is translated with a non-uniform speed that actively coordinates co-translational folding of protein domains. Using structure-based homology we identified the structural domains in epoxide hydrolases (EHs) and introduced slow-translating codons to delineate the translation of single domains. These changes in translation speed dramatically improved the solubility of two EHs of metagenomic origin in Escherichia coli. Conversely, the importance of transient attenuation for the folding, and consequently solubility, of EH was evidenced with a member of the EH family from Agrobacterium radiobacter, which partitions in the soluble fraction when expressed in E. coli. Synonymous substitutions of codons shaping the slow-transiting regions to fast-translating codons render this protein insoluble. Furthermore, we show that low protein yield can be enhanced by decreasing the free folding energy of the initial 5’-coding region, which can disrupt mRNA secondary structure and enhance ribosomal loading. This study provides direct experimental evidence that mRNA is not a mere messenger for translation of codons into amino acids but bears an additional layer of information for folding, solubility and expression level of the encoded protein. Furthermore, it provides a general frame on how to modulate and fine-tune gene expression of a target protein. PMID:25965266

  19. The E4 protein; structure, function and patterns of expression

    SciTech Connect

    Doorbar, John

    2013-10-15

    The papillomavirus E4 open reading frame (ORF) is contained within the E2 ORF, with the primary E4 gene-product (E1{sup ∧}E4) being translated from a spliced mRNA that includes the E1 initiation codon and adjacent sequences. E4 is located centrally within the E2 gene, in a region that encodes the E2 protein′s flexible hinge domain. Although a number of minor E4 transcripts have been reported, it is the product of the abundant E1{sup ∧}E4 mRNA that has been most extensively analysed. During the papillomavirus life cycle, the E1{sup ∧}E4 gene products generally become detectable at the onset of vegetative viral genome amplification as the late stages of infection begin. E4 contributes to genome amplification success and virus synthesis, with its high level of expression suggesting additional roles in virus release and/or transmission. In general, E4 is easily visualised in biopsy material by immunostaining, and can be detected in lesions caused by diverse papillomavirus types, including those of dogs, rabbits and cattle as well as humans. The E4 protein can serve as a biomarker of active virus infection, and in the case of high-risk human types also disease severity. In some cutaneous lesions, E4 can be expressed at higher levels than the virion coat proteins, and can account for as much as 30% of total lesional protein content. The E4 proteins of the Beta, Gamma and Mu HPV types assemble into distinctive cytoplasmic, and sometimes nuclear, inclusion granules. In general, the E4 proteins are expressed before L2 and L1, with their structure and function being modified, first by kinases as the infected cell progresses through the S and G2 cell cycle phases, but also by proteases as the cell exits the cell cycle and undergoes true terminal differentiation. The kinases that regulate E4 also affect other viral proteins simultaneously, and include protein kinase A, Cyclin-dependent kinase, members of the MAP Kinase family and protein kinase C. For HPV16 E1{sup

  20. Combined protein construct and synthetic gene engineering for heterologous protein expression and crystallization using Gene Composer

    SciTech Connect

    Raymond, Amy; Lovell, Scott; Lorimer, Don; Walchli, John; Mixon, Mark; Wallace, Ellen; Thompkins, Kaitlin; Archer, Kimberly; Burgin, Alex; Stewart, Lance

    2009-12-01

    With the goal of improving yield and success rates of heterologous protein production for structural studies we have developed the database and algorithm software package Gene Composer. This freely available electronic tool facilitates the information-rich design of protein constructs and their engineered synthetic gene sequences, as detailed in the accompanying manuscript. In this report, we compare heterologous protein expression levels from native sequences to that of codon engineered synthetic gene constructs designed by Gene Composer. A test set of proteins including a human kinase (P38{alpha}), viral polymerase (HCV NS5B), and bacterial structural protein (FtsZ) were expressed in both E. coli and a cell-free wheat germ translation system. We also compare the protein expression levels in E. coli for a set of 11 different proteins with greatly varied G:C content and codon bias. The results consistently demonstrate that protein yields from codon engineered Gene Composer designs are as good as or better than those achieved from the synonymous native genes. Moreover, structure guided N- and C-terminal deletion constructs designed with the aid of Gene Composer can lead to greater success in gene to structure work as exemplified by the X-ray crystallographic structure determination of FtsZ from Bacillus subtilis. These results validate the Gene Composer algorithms, and suggest that using a combination of synthetic gene and protein construct engineering tools can improve the economics of gene to structure research.

  1. Easy mammalian expression and crystallography of maltose-binding protein-fused human proteins.

    PubMed

    Bokhove, Marcel; Sadat Al Hosseini, Hamed; Saito, Takako; Dioguardi, Elisa; Gegenschatz-Schmid, Katharina; Nishimura, Kaoru; Raj, Isha; de Sanctis, Daniele; Han, Ling; Jovine, Luca

    2016-04-01

    We present a strategy to obtain milligrams of highly post-translationally modified eukaryotic proteins, transiently expressed in mammalian cells as rigid or cleavable fusions with a mammalianized version of bacterial maltose-binding protein (mMBP). This variant was engineered to combine mutations that enhance MBP solubility and affinity purification, as well as provide crystal-packing interactions for increased crystallizability. Using this cell type-independent approach, we could increase the expression of secreted and intracellular human proteins up to 200-fold. By molecular replacement with MBP, we readily determined five novel high-resolution structures of rigid fusions of targets that otherwise defied crystallization. PMID:26850170

  2. Easy mammalian expression and crystallography of maltose-binding protein-fused human proteins

    PubMed Central

    Bokhove, Marcel; Sadat Al Hosseini, Hamed; Saito, Takako; Dioguardi, Elisa; Gegenschatz-Schmid, Katharina; Nishimura, Kaoru; Raj, Isha; de Sanctis, Daniele; Han, Ling; Jovine, Luca

    2016-01-01

    We present a strategy to obtain milligrams of highly post-translationally modified eukaryotic proteins, transiently expressed in mammalian cells as rigid or cleavable fusions with a mammalianized version of bacterial maltose-binding protein (mMBP). This variant was engineered to combine mutations that enhance MBP solubility and affinity purification, as well as provide crystal-packing interactions for increased crystallizability. Using this cell type-independent approach, we could increase the expression of secreted and intracellular human proteins up to 200-fold. By molecular replacement with MBP, we readily determined five novel high-resolution structures of rigid fusions of targets that otherwise defied crystallization. PMID:26850170

  3. Expression, Delivery and Function of Insecticidal Proteins Expressed by Recombinant Baculoviruses

    PubMed Central

    Kroemer, Jeremy A.; Bonning, Bryony C.; Harrison, Robert L.

    2015-01-01

    Since the development of methods for inserting and expressing genes in baculoviruses, a line of research has focused on developing recombinant baculoviruses that express insecticidal peptides and proteins. These recombinant viruses have been engineered with the goal of improving their pesticidal potential by shortening the time required for infection to kill or incapacitate insect pests and reducing the quantity of crop damage as a consequence. A wide variety of neurotoxic peptides, proteins that regulate insect physiology, degradative enzymes, and other potentially insecticidal proteins have been evaluated for their capacity to reduce the survival time of baculovirus-infected lepidopteran host larvae. Researchers have investigated the factors involved in the efficient expression and delivery of baculovirus-encoded insecticidal peptides and proteins, with much effort dedicated to identifying ideal promoters for driving transcription and signal peptides that mediate secretion of the expressed target protein. Other factors, particularly translational efficiency of transcripts derived from recombinant insecticidal genes and post-translational folding and processing of insecticidal proteins, remain relatively unexplored. The discovery of RNA interference as a gene-specific regulation mechanism offers a new approach for improvement of baculovirus biopesticidal efficacy through genetic modification. PMID:25609310

  4. Expression and localization of X11 family proteins in neurons.

    PubMed

    Motodate, Rika; Saito, Yuhki; Hata, Saori; Suzuki, Toshiharu

    2016-09-01

    The X11/Mint family of proteins comprises X11/X11α/Mint1, X11L/X11β/Mint2, and X11L2/X11γ/Mint3. Each of these molecules is an adaptor protein that contains a phosphotyrosine interaction/binding (PI/PTB) and two PDZ domains in its carboxy-terminal region. X11/Mint family members associate with a broad spectrum of membrane proteins, including Alzheimer's β-amyloid precursor protein (APP), alcadeins, and low density lipoprotein receptor proteins, as well as various cytoplasmic proteins including Arf, kalirin-7, and Munc18. In particular, X11 and X11L are thought to play various roles in the regulation of neural functions in brain. Nevertheless, the protein levels and respective localization of individual family members remain controversial. We analyzed the protein levels of X11 and X11L in the corresponding single- and double-knockout mice. X11 and X11L did not exhibit obvious changes of their protein levels when the other was absent, especially in cerebrum in which they were widely co-expressed. In cerebellum, X11 and X11L localized in characteristic patterns in various types of neurons, and X11 protein level increased without an obvious ectopic localization in X11L-knockout mice. Interestingly, only X11L protein existed specifically in brain, whereas, contrary to the accepted view, X11 protein was detected at the highest levels in brain but was also strongly detected in pancreas, testis, and paranephros. Together, our results indicate that both X11 and X11L exert largely in brain neurons, but X11 may also function in peripheral tissues. PMID:27268412

  5. LC–MS Based Detection of Differential Protein Expression

    PubMed Central

    Tuli, Leepika; Ressom, Habtom W.

    2010-01-01

    While several techniques are available in proteomics, LC-MS based analysis of complex protein/peptide mixtures has turned out to be a mainstream analytical technique for quantitative proteomics. Significant technical advances at both sample preparation/separation and mass spectrometry levels have revolutionized comprehensive proteome analysis. Moreover, automation and robotics for sample handling process permit multiple sampling with high throughput. For LC-MS based quantitative proteomics, sample preparation turns out to be critical step, as it can significantly influence sensitivity of downstream analysis. Several sample preparation strategies exist, including depletion of high abundant proteins or enrichment steps that facilitate protein quantification but with a compromise of focusing on a smaller subset of a proteome. While several experimental strategies have emerged, certain limitations such as physiochemical properties of a peptide/protein, protein turnover in a sample, analytical platform used for sample analysis and data processing, still imply challenges to quantitative proteomics. Other aspects that make analysis of a proteome a challenging task include dynamic nature of a proteome, need for efficient and fast analysis of protein due to its constant modifications inside a cell, concentration range of proteins that exceed dynamic range of a single analytical method, and absence of appropriate bioinformatics tools for analysis of large volume and high dimensional data. This paper gives an overview of various LC-MS methods currently used in quantitative proteomics and their potential for detecting differential protein expression. Fundamental steps such as sample preparation, LC separation, mass spectrometry, quantitative assessment and protein identification are discussed. For quantitative assessment of protein expression, both label and label free approaches are evaluated for their set of merits and demerits. While most of these methods edge on providing

  6. Altered Expression of Bone Morphogenetic Protein Accessory Proteins in Murine and Human Pulmonary Fibrosis.

    PubMed

    Murphy, Noelle; Gaynor, Katherine U; Rowan, Simon C; Walsh, Sinead M; Fabre, Aurelie; Boylan, John; Keane, Michael P; McLoughlin, Paul

    2016-03-01

    Idiopathic pulmonary fibrosis is a chronic, progressive fibrotic disease with a poor prognosis. The balance between transforming growth factor β1 and bone morphogenetic protein (BMP) signaling plays an important role in tissue homeostasis, and alterations can result in pulmonary fibrosis. We hypothesized that multiple BMP accessory proteins may be responsible for maintaining this balance in the lung. Using the bleomycin mouse model for fibrosis, we examined an array of BMP accessory proteins for changes in mRNA expression. We report significant increases in mRNA expression of gremlin 1, noggin, follistatin, and follistatin-like 1 (Fstl1), and significant decreases in mRNA expression of chordin, kielin/chordin-like protein, nephroblastoma overexpressed gene, and BMP and activin membrane-bound inhibitor (BAMBI). Protein expression studies demonstrated increased levels of noggin, BAMBI, and FSTL1 in the lungs of bleomycin-treated mice and in the lungs of idiopathic pulmonary fibrosis patients. Furthermore, we demonstrated that transforming growth factor β stimulation resulted in increased expression of noggin, BAMBI, and FSTL1 in human small airway epithelial cells. These results provide the first evidence that multiple BMP accessory proteins are altered in fibrosis and may play a role in promoting fibrotic injury. PMID:26765958

  7. Morbillivirus and henipavirus attachment protein cytoplasmic domains differently affect protein expression, fusion support and particle assembly.

    PubMed

    Sawatsky, Bevan; Bente, Dennis A; Czub, Markus; von Messling, Veronika

    2016-05-01

    The amino-terminal cytoplasmic domains of paramyxovirus attachment glycoproteins include trafficking signals that influence protein processing and cell surface expression. To characterize the role of the cytoplasmic domain in protein expression, fusion support and particle assembly in more detail, we constructed chimeric Nipah virus (NiV) glycoprotein (G) and canine distemper virus (CDV) haemagglutinin (H) proteins carrying the respective heterologous cytoplasmic domain, as well as a series of mutants with progressive deletions in this domain. CDV H retained fusion function and was normally expressed on the cell surface with a heterologous cytoplasmic domain, while the expression and fusion support of NiV G was dramatically decreased when its cytoplasmic domain was replaced with that of CDV H. The cell surface expression and fusion support functions of CDV H were relatively insensitive to cytoplasmic domain deletions, while short deletions in the corresponding region of NiV G dramatically decreased both. In addition, the first 10 residues of the CDV H cytoplasmic domain strongly influence its incorporation into virus-like particles formed by the CDV matrix (M) protein, while the co-expression of NiV M with NiV G had no significant effect on incorporation of G into particles. The cytoplasmic domains of both the CDV H and NiV G proteins thus contribute differently to the virus life cycle. PMID:26813519

  8. Expression of Exocytosis Proteins in Rat Supraoptic Nucleus Neurones

    PubMed Central

    Tobin, V.; Schwab, Y.; Lelos, N.; Onaka, T.; Pittman, Q. J.; Ludwig, M.

    2012-01-01

    In magnocellular neurones of the supraoptic nucleus (SON), the neuropeptides vasopressin and oxytocin are synthesised and packaged into large dense-cored vesicles (LDCVs). These vesicles undergo regulated exocytosis from nerve terminals in the posterior pituitary gland and from somata/dendrites in the SON. Regulated exocytosis of LDCVs is considered to involve the soluble N-ethylmaleimide sensitive fusion protein attachment protein receptor (SNARE) complex [comprising vesicle associated membrane protein 2 (VAMP-2), syntaxin-1 and soluble N-ethylmaleimide attachment protein-25 (SNAP-25)] and regulatory proteins [such as synaptotagmin-1, munc-18 and Ca2+-dependent activator protein for secretion (CAPS-1)]. Using fluorescent immunocytochemistry and confocal microscopy, in both oxytocin and vasopressin neurones, we observed VAMP-2, SNAP-25 and syntaxin-1-immunoreactivity in axon terminals. The somata and dendrites contained syntaxin-1 and other regulatory exocytosis proteins, including munc-18 and CAPS-1. However, the distribution of VAMP-2 and synaptotagmin-1 in the SON was limited to putative pre-synaptic contacts because they co-localised with synaptophysin (synaptic vesicle marker) and had no co-localisation with either oxytocin or vasopressin. SNAP-25 immunoreactivity in the SON was limited to glial cell processes and was not detected in oxytocin or vasopressin somata/dendrites. The present results indicate differences in the expression and localisation of exocytosis proteins between the axon terminals and somata/dendritic compartment. The absence of VAMP-2 and SNAP-25 immunoreactivity from the somata/dendrites suggests that there might be different SNARE protein isoforms expressed in these compartments. Alternatively, exocytosis of LDCVs from somata/dendrites may use a different mechanism from that described by the SNARE complex theory. PMID:21988098

  9. Tools to cope with difficult-to-express proteins.

    PubMed

    Saccardo, Paolo; Corchero, José Luís; Ferrer-Miralles, Neus

    2016-05-01

    The identification of DNA coding sequences contained in the genome of many organisms coupled to the use of high throughput approaches has fueled the field of recombinant protein production. Apart from basic research interests, the growing relevance of this field is highlighted by the global sales of the top ten biopharmaceuticals on the market, which exceeds the trillion USD in a steady increasing tendency. Therefore, the demand of biological compounds seems to have a long run on the market. One of the most popular expression systems is based on Escherichia coli cells which apart from being cost-effective counts with a large selection of resources. However, a significant percentage of the genes of interest are not efficiently expressed in this system, or the expressed proteins are accumulated within aggregates, degraded or lacking the desired biological activity, being finally discarded. In some instances, expressing the gene in a homologous expression system might alleviate those drawbacks but then the process usually increases in complexity and is not as cost-effective as the prokaryotic systems. An increasing toolbox is available to approach the production and purification of those difficult-to-express proteins, including different expression systems, promoters with different strengths, cultivation media and conditions, solubilization tags and chaperone coexpression, among others. However, in most cases, the process follows a non-integrative trial and error strategy with discrete success. This review is focused on the design of the whole process by using an integrative approach, taken into account the accumulated knowledge of the pivotal factors that affect any of the key processes, in an attempt to rationalize the efforts made in this appealing field. PMID:27079572

  10. Differential Expression of Borrelia burgdorferi Proteins during Growth In Vitro

    PubMed Central

    Ramamoorthy, Ramesh; Philipp, Mario T.

    1998-01-01

    In an earlier paper we described the transcriptionally regulated differential levels of expression of two lipoproteins of Borrelia burgdorferi, P35 and P7.5, during growth of the spirochetes in culture from logarithmic phase to stationary phase (K. J. Indest, R. Ramamoorthy, M. Solé, R. D. Gilmore, B. J. B. Johnson, and M. T. Philipp, Infect. Immun. 65:1165–1171, 1997). Here we further assess this phenomenon by investigating whether the expression of other antigens of B. burgdorferi, including some well-characterized ones, are also regulated in a growth-phase-dependent manner in vitro. These studies revealed 13 additional antigens, including OspC, BmpD, and GroEL, that were upregulated 2- to 66-fold and a 28-kDa protein that was downregulated 2- to 10-fold, during the interval between the logarithmic- and stationary-growth phases. Unlike with these in vitro-regulated proteins, the levels of expression of OspA, OspB, P72, flagellin, and BmpA remained unchanged throughout growth of the spirochetes in culture. Furthermore, ospAB, bmpAB, groEL, and fla all exhibited similar mRNA profiles, which is consistent with the constitutive expression of these genes. By contrast, the mRNA and protein profiles of ospC and bmpD indicated regulated expression of these genes. While bmpD exhibited a spike in mRNA expression in early stationary phase, ospC maintained a relatively higher level of mRNA throughout culture. These findings demonstrate that there are additional genes besides P7.5 and P35 whose regulated expression can be investigated in vitro and which may thus serve as models to facilitate the study of regulatory mechanisms in an organism that cycles between an arthropod and a vertebrate host. PMID:9784512

  11. Expression of interleukin-17RC protein in normal human tissues

    PubMed Central

    Ge, Dongxia; You, Zongbing

    2008-01-01

    Background Interleukin-17 (IL-17) cytokines and receptors play an important role in many autoimmune and inflammatory diseases. IL-17 receptors IL-17RA and IL-17RC have been found to form a heterodimer for mediating the signals of IL-17A and IL-17F cytokines. While the function and signaling pathway of IL-17RA has been revealed, IL-17RC has not been well characterized. The function and signaling pathway of IL-17RC remain largely unknown. The purpose of the present study was to systematically examine IL-17RC protein expression in 53 human tissues. Results IL-17RC expression in 51 normal human tissues and two benign tumors (i.e., lymphangioma and parathyroid adenoma) on the tissue microarrays was determined by immunohistochemical staining, using two polyclonal antibodies against IL-17RC. IL-17RC protein was expressed in many cell types including the myocardial cells, vascular and lymphatic endothelial cells, glandular cells (of the adrenal, parathyroid, pituitary, thyroid, pancreas, parotid salivary, and subepidermal glands), epithelial cells (of the esophagus, stomach, intestine, anus, renal tubule, breast, cervix, Fallopian tube, epididymis, seminal vesicle, prostate, gallbladder, bronchus, lung, and skin), oocytes in the ovary, Sertoli cells in the testis, motor neurons in the spinal cord, autonomic ganglia and nerves in the intestine, skeletal muscle cells, adipocytes, articular chondrocytes, and synovial cells. High levels of IL-17RC protein expression were observed in most vascular and lymphatic endothelium and squamous epithelium. The epithelium of the breast, cervix, Fallopian tube, kidney, bladder and bronchus also expressed high levels of IL-17RC, so did the glandular cells in the adrenal cortex, parotid salivary and subepidermal glands. In contrast, IL-17RC protein was not detectable in the smooth muscle cells, fibroblasts, antral mucosa of the stomach, mucosa of the colon, endometrium of the uterus, neurons of the brain, hepatocytes, or lymphocytes

  12. Survivin and related proteins in canine mammary tumors: immunohistochemical expression.

    PubMed

    Bongiovanni, L; Romanucci, M; Malatesta, D; D'Andrea, A; Ciccarelli, A; Della Salda, L

    2015-03-01

    Survivin is reexpressed in most human breast cancers, where its expression has been associated with tumor aggressiveness, poor prognosis, and poor response to therapy. Survivin expression was evaluated in 41 malignant canine mammary tumors (CMTs) by immunohistochemistry, in relation to histological grade and stage, and correlated with that of some related molecules (β-catenin, caspase 3, heat shock proteins) to understand their possible role in canine mammary tumorigenesis. An increase in nuclear survivin expression, compared with healthy mammary glands, was observed in CMTs, where nuclear immunolabeling was related to the presence of necrosis. No statistically significant relation was found between the expression of the investigated molecules and the histological grade or stage. The present study may suggest an important involvement of survivin in CMT tumorigenesis. Its overexpression in most of the cases evaluated might suggest that targeting survivin in CMTs may be a valid anticancer therapy. PMID:24686389

  13. Expression and serological reactivity of hemorrhagic enteritis virus hexon protein.

    PubMed

    Lobová, Dana; Celer, Vladimír

    2016-05-01

    The aim of this work was to express the recombinant hexon protein of the hemorrhagic enteritis virus, to establish the diagnostic value of this protein for serological detection of antibodies in turkey serum samples and to assess seroprevalence of the infection in the Czech Republic. The N' terminal part of the hexon protein was expressed in a bacterial expression system and used as an antigen in an ELISA test for the detection of hemorrhagic enteritis virus specific antibodies in turkey sera. Validation of the test was performed by comparison with a commercially available ELISA test. Serological reactivity was assessed on a panel of 126 turkey sera by a newly developed ELISA test. Serum samples were taken from turkey farms with the history of hemorrhagic enteritis virus infection, from farms with animals free of infection, and from turkey farms following vaccination. Both ELISA kits gave identical results (100 %) with the tested sera. ELISA based on the recombinant hexon protein thus proved useful and cheaper for detection of antibodies in turkey flocks infected with the hemorrhagic enteritis virus. PMID:26471497

  14. Human testis expresses a specific poly(A)-binding protein.

    PubMed

    Féral, C; Guellaën, G; Pawlak, A

    2001-05-01

    In testis mRNA stability and translation initiation are extensively under the control of poly(A)-binding proteins (PABP). Here we have cloned a new human testis-specific PABP (PABP3) of 631 amino acids (70.1 kDa) with 92.5% identical residues to the ubiquitous PABP1. A northern blot of multiple human tissues hybridised with PABP3- and PABP1-specific oligonucleotide probes revealed two PABP3 mRNAs (2.1 and 2.5 kb) detected only in testis, whereas PABP1 mRNA (3.2 kb) was present in all tested tissues. In human adult testis, PABP3 mRNA expression was restricted to round spermatids, whereas PABP1 was expressed in these cells as well as in pachytene spermatocytes. PABP3-specific antibodies identified a protein of 70 kDa in human testis extracts. This protein binds poly(A) with a slightly lower affinity as compared to PABP1. The human PABP3 gene is intronless with a transcription start site 61 nt upstream from the initiation codon. A sequence of 256 bp upstream from the transcription start site drives the promoter activity of PABP3 and its tissue-specific expression. The expression of PABP3 might be a way to bypass PABP1 translational repression and to produce the amount of PABP needed for active mRNA translation in spermatids. PMID:11328870

  15. Expression of Tyrosine Hydroxylase is Negatively Regulated Via Prion Protein.

    PubMed

    da Luz, Marcio Henrique Mello; Glezer, Isaias; Xavier, Andre Machado; da Silva, Marcelo Alberti Paiva; Pino, Jessica Monteiro Volejnik; Zamith, Thiago Panaro; Vieira, Taynara Fernanda; Antonio, Bruno Brito; Antunes, Hanna Karen Moreira; Martins, Vilma Regina; Lee, Kil Sun

    2016-07-01

    Cellular prion protein (PrP(C)) is a glycoprotein of the plasma membrane that plays pleiotropic functions by interacting with multiple signaling complexes at the cell surface. Recently, a number of studies have reported the involvement of PrP(C) in dopamine metabolism and signaling, including its interactions with tyrosine hydroxylase (TH) and dopamine receptors. However, the outcomes reported by independent studies are still debatable. Therefore in this study, we investigated the effects of PrP(C) on the TH expression during the differentiation of N2a cells with dibutyryl-cAMP, a well-known cAMP analog that activates TH transcription. Upon differentiation, TH was induced with concomitant reduction of PrP(C) at protein level, but not at mRNA level. shRNA-mediated PrP(C) reduction increased the basal level of TH at both mRNA and protein levels without dibutyryl-cAMP treatment. This phenotype was reversed by re-expression of PrP(C). PrP(C) knockdown also potentiated the effect of dibutyryl-cAMP on TH expression. Our findings suggest that PrP(C) has suppressive effects on TH expression. As a consequence, altered PrP(C) functions may affect the regulation of dopamine metabolism and related neurological disorders. PMID:26975317

  16. Stepwise optimization of a low-temperature Bacillus subtilis expression system for "difficult to express" proteins.

    PubMed

    Welsch, Norma; Homuth, Georg; Schweder, Thomas

    2015-08-01

    In order to improve the overproduction of "difficult to express" proteins, a low-temperature expression system for Bacillus subtilis based on the cold-inducible promoter of the desaturase-encoding des gene was constructed. Selected regulatory DNA sequence elements from B. subtilis genes known to be cold-inducible were fused to different model genes. It could be demonstrated that these regulatory elements are able to mediate increased heterologous gene expression, either by improved translation efficiency or by higher messenger RNA (mRNA) stability. In case of a cold-adapted β-galactosidase from Pseudoalteromonas haloplanktis TAE79A serving as the model, significantly higher expression was achieved by fusing its coding sequence to the so-called "downstream box" sequence of cspB encoding the major B. subtilis cold-shock protein. The combination of this fusion with a cspB 5'-UTR stem-loop structure resulted in further enhancement of the β-galactosidase expression. In addition, integration of the transcription terminator of the B. subtilis cold-inducible bkd operon downstream of the target genes caused a higher mRNA stability and enabled thus a further significant increase in expression. Finally, the fully optimized expression system was validated by overproducing a B. subtilis xylanase as well as an α-glucosidase from Saccharomyces cerevisiae, the latter known for tending to form inclusion bodies. These analyses verified the applicability of the engineered expression system for extracellular and intracellular protein synthesis in B. subtilis, thereby confirming the suitability of this host organism for the overproduction of critical, poorly soluble proteins. PMID:25851716

  17. Effects of Ketoconazole on the Biodistribution and Metabolism of [11C]Loperamide and [11C]N-Desmethyl-loperamide in Wild-type and P-gp Knockout Mice

    PubMed Central

    Seneca, Nicholas; Zoghbi, Sami S.; Shetty, H. Umesha; Tuan, Edward; Kannan, Pavitra; Taku, Andrew; Innis, Robert B.; Pike, Victor W.

    2010-01-01

    Introduction [11C]Loperamide and [11C]N-desmethyl-loperamide ([11C]dLop) have been proposed as radiotracers for imaging brain P-glycoprotein (P-gp) function. A major route of [11C]loperamide metabolism is N-demethylation to [11C]dLop. We aimed to test whether inhibition of CYP3A4 with ketoconazole might reduce the metabolism of [11C]loperamide and [11C]dLop in mice, and thereby improve the quality of these radiotracers. Methods Studies were performed in wild-type and P-gp knockout (mdr–1a/b −/−) mice. During each of seven study sessions, one pair of mice, comprising one wild-type and one knockout mouse, waspretreated with ketoconazole (50 mg/kg, i.p.) while another such pair was left untreated. Mice were sacrificed at 30 min after injection of [11C]loperamide or [11C]dLop. Whole brain and plasma samples were measured for radioactivity and analyzed with radio-HPLC. Results Ketoconazole increased the plasma concentrations of [11C]loperamide and its main radiometabolite, [11C]dLop, by about two-fold in both wild-type and knockout mice, whereas the most polar radiometabolite was decreased three-fold. Furthermore, ketoconazole increased the brain concentrations of [11C]loperamide and the radiometabolite [11C]dLop by about two-fold in knockout mice, and decreased the brain concentrations of the major and most polar radiometabolite in wild-type and knockout mice by 82 and 49%, respectively. In contrast, ketoconazole had no effect on plasma and brain distribution of administered [11C]dLop and its radiometabolites in either wild-type or knockout mice, except to increase the low plasma [11C]dLop concentration. The least polar radiometabolite of [11C]dLop was identified with LC-MSn as the N-hydroxymethyl analog of [11C]dLop and this also behaved as a P-gp substrate. Conclusion In this study, ketoconazole (50 mg/kg, i.p.) proved partiallyeffective for inhibiting the N-demethylation of [11C]loperamide in mouse in vivo but had relatively smaller or no effect on [11C

  18. Alternative Eukaryotic Expression Systems for the Production of Proteins and Protein Complexes.

    PubMed

    Gómez, Sara; López-Estepa, Miguel; Fernández, Francisco J; Suárez, Teresa; Vega, M Cristina

    2016-01-01

    Besides the most established expression hosts, several eukaryotic microorganisms and filamentous fungi have also been successfully used as platforms for the production of foreign proteins. Filamentous fungi and Dictyostelium discoideum are two prominent examples. Filamentous fungi, typically Aspergillus and Trichoderma, are usually employed for the industrial production of enzymes and secondary metabolites for food processing, pharmaceutical drugs production, and textile and paper applications, with multiple products already accepted for their commercialization. The low cost of culture medium components, high secretion capability directly to the extracellular medium, and the intrinsic ability to produce post-translational modifications similar to the mammalian type, have promoted this group as successful hosts for the expression of proteins, including examples from phylogenetically distant groups: humans proteins such as IL-2, IL-6 or epithelial growth factor; α-galactosidase from plants; or endoglucanase from Cellulomonas fimi, among others. D. discoideum is a social amoeba that can be used as an expression platform for a variety of proteins, which has been extensively illustrated for cytoskeletal proteins. New vectors for heterologous expression in D. discoideum have been recently developed that might increase the usefulness of this system and expand the range of protein classes that can be tackled. Continuous developments are ongoing to improve strains, promoters, production and downstream processes for filamentous fungi, D. discoideum, and other alternative eukaryotic hosts. Either for the overexpression of individual genes, or in the coexpression of multiples genes, this chapter illustrates the enormous possibilities offered by these groups of eukaryotic organisms. PMID:27165325

  19. Expression, purification and crystallization of a lyssavirus matrix (M) protein

    SciTech Connect

    Assenberg, René; Delmas, Olivier; Graham, Stephen C.; Verma, Anil; Berrow, Nick; Stuart, David I.; Owens, Raymond J.; Bourhy, Hervé; Grimes, Jonathan M.

    2008-04-01

    The expression, purification and crystallization of the full-length matrix protein from three lyssaviruses is described. The matrix (M) proteins of lyssaviruses (family Rhabdoviridae) are crucial to viral morphogenesis as well as in modulating replication and transcription of the viral genome. To date, no high-resolution structural information has been obtained for full-length rhabdovirus M. Here, the cloning, expression and purification of the matrix proteins from three lyssaviruses, Lagos bat virus (LAG), Mokola virus and Thailand dog virus, are described. Crystals have been obtained for the full-length M protein from Lagos bat virus (LAG M). Successful crystallization depended on a number of factors, in particular the addition of an N-terminal SUMO fusion tag to increase protein solubility. Diffraction data have been recorded from crystals of native and selenomethionine-labelled LAG M to 2.75 and 3.0 Å resolution, respectively. Preliminary analysis indicates that these crystals belong to space group P6{sub 1}22 or P6{sub 5}22, with unit-cell parameters a = b = 56.9–57.2, c = 187.9–188.6 Å, consistent with the presence of one molecule per asymmetric unit, and structure determination is currently in progress.

  20. Protein inhibitor of activated STAT3 inhibits adipogenic gene expression

    SciTech Connect

    Deng Jianbei; Hua Kunjie; Caveney, Erica J.; Takahashi, Nobuyuki; Harp, Joyce B. . E-mail: jharp@unc.edu

    2006-01-20

    Protein inhibitor of activated STAT3 (PIAS3), a cytokine-induced repressor of signal transducer and activator of transcription 3 (STAT3) and a modulator of a broad array of nuclear proteins, is expressed in white adipose tissue, but its role in adipogenesis is not known. Here, we determined that PIAS3 was constitutively expressed in 3T3-L1 cells at all stages of adipogenesis. However, it translocated from the nucleus to the cytoplasm 4 days after induction of differentiation by isobutylmethylxanthine, dexamethasone, and insulin (MDI). In ob/ob mice, PIAS3 expression was increased in white adipose tissue depots compared to lean mice and was found in the cytoplasm of adipocytes. Overexpression of PIAS3 in differentiating preadipocytes, which localized primarily to the nucleus, inhibited mRNA level gene expression of adipogenic transcription factors C/EBP{alpha} and PPAR{gamma}, as well as their downstream target genes aP2 and adiponectin. PIAS3 also inhibited C/EBP{alpha} promoter activation mediated specifically by insulin, but not dexamethasone or isobutylmethylxanthine. Taken together, these data suggest that PIAS3 may play an inhibitory role in adipogenesis by modulating insulin-activated transcriptional activation events. Increased PIAS3 expression in adipose tissue may play a role in the metabolic disturbances of obesity.

  1. High level expression of mammalian protein farnesyltransferase in a baculovirus system. The purified protein contains zinc.

    PubMed

    Chen, W J; Moomaw, J F; Overton, L; Kost, T A; Casey, P J

    1993-05-01

    The mammalian enzyme protein farnesyltransferase is a heterodimeric protein that catalyzes the addition of a farnesyl isoprenoid to a cysteine in ras proteins. Since oncogenic forms of ras proteins require the farnesyl group for transforming activity, the structure and mechanism of this enzyme are important to define. However, such studies have been difficult to approach because of the low abundance of the enzyme in mammalian tissues and hence the problems of obtaining large quantities of the protein. We report here the co-expression of the two subunits of protein farnesyltransferase by Sf9 cells infected with a recombinant baculovirus containing the coding sequences of both polypeptides. This results in the production of milligram quantities of enzyme which can be readily purified by conventional chromatographic methods. The individual subunits of the enzyme can also be expressed in the Sf9 cells, but the ability to reconstitute active enzyme from extracts containing individual subunits is quite low. In contrast, the enzyme produced by co-expression of the two subunits is fully active and retains the properties of the mammalian form, including the specificity for the COOH-terminal amino acid of substrate proteins and the ability to bind short peptides encompassing the prenylation site of a ras protein. Furthermore, through atomic absorption analysis of the purified protein, we have confirmed the previous tentative assignment of protein farnesyltransferase as a zinc metalloenzyme by demonstrating that it contains an essentially stoichiometric amount of zinc. The ability to produce and purify milligram quantities of protein farnesyltransferase readily will allow detailed mechanistic and structural studies on this enzyme. PMID:8486655

  2. HIV-1 Tat Protein Enhances Expression and Function of Breast Cancer Resistance Protein.

    PubMed

    Zhou, Yancong; Zhang, Kun; Yin, Xiaojie; Nie, Qichang; Ma, Yonggang

    2016-01-01

    ATP binding cassette (ABC) transporters can transfer a variety of antiviral agents from the cytoplasm to body fluid, which results in a reduced intracellular concentration of the drugs. Proteins of HIV-1, e.g., Tat and gp120, altered some types of ABC transporter expression in brain microvascular endothelial cells and astrocytes. However, the effect of Tat on ABC transporters in T lymphocytes is unclear. In this study the status of breast cancer resistance protein (BCRP) in Tat expressing cell lines was examined with real-time PCR and flow cytometry. It was found that HIV-1 Tat protein upregulated BCRP expression and enhanced efflux mediated by BCRP significantly, which could inhibit antiviral drugs from entering infected cells and interfere with the therapeutic effect of HAART. PMID:26367065

  3. Cooperative working of bacterial chromosome replication proteins generated by a reconstituted protein expression system

    PubMed Central

    Fujiwara, Kei; Katayama, Tsutomu; Nomura, Shin-ichiro M.

    2013-01-01

    Replication of all living cells relies on the multirounds flow of the central dogma. Especially, expression of DNA replication proteins is a key step to circulate the processes of the central dogma. Here we achieved the entire sequential transcription–translation–replication process by autonomous expression of chromosomal DNA replication machineries from a reconstituted transcription–translation system (PURE system). We found that low temperature is essential to express a complex protein, DNA polymerase III, in a single tube using the PURE system. Addition of the 13 genes, encoding initiator, DNA helicase, helicase loader, RNA primase and DNA polymerase III to the PURE system gave rise to a DNA replication system by a coupling manner. An artificial genetic circuit demonstrated that the DNA produced as a result of the replication is able to provide genetic information for proteins, indicating the in vitro central dogma can sequentially undergo two rounds. PMID:23737447

  4. Ribozymes, riboswitches and beyond: regulation of gene expression without proteins

    PubMed Central

    Serganov, Alexander; Patel, Dinshaw J.

    2015-01-01

    Although various functions of RNA are carried out in conjunction with proteins, some catalytic RNAs, or ribozymes, which contribute to a range of cellular processes, require little or no assistance from proteins. Furthermore, the discovery of metabolite-sensing riboswitches and other types of RNA sensors has revealed RNA-based mechanisms that cells use to regulate gene expression in response to internal and external changes. Structural studies have shown how these RNAs can carry out a range of functions. In addition, the contribution of ribozymes and riboswitches to gene expression is being revealed as far more widespread than was previously appreciated. These findings have implications for understanding how cellular functions might have evolved from RNA-based origins. PMID:17846637

  5. Improving Protein Expression Prediction Using Extra Features and Ensemble Averaging

    PubMed Central

    Fernandes, Armando; Vinga, Susana

    2016-01-01

    The article focus is the improvement of machine learning models capable of predicting protein expression levels based on their codon encoding. Support vector regression (SVR) and partial least squares (PLS) were used to create the models. SVR yields predictions that surpass those of PLS. It is shown that it is possible to improve the models predictive ability by using two more input features, codon identification number and codon count, besides the already used codon bias and minimum free energy. In addition, applying ensemble averaging to the SVR or PLS models also improves the results even further. The present work motivates the test of different ensembles and features with the aim of improving the prediction models whose correlation coefficients are still far from perfect. These results are relevant for the optimization of codon usage and enhancement of protein expression levels in synthetic biology problems. PMID:26934190

  6. Expression data on liver metabolic pathway genes and proteins

    PubMed Central

    Raja Gopal Reddy, Mooli; Pavan Kumar, Chodisetti; Mahesh, Malleswarapu; Sravan Kumar, Manchiryala; Jeyakumar, Shanmugam M.

    2016-01-01

    Here, we present the expression data on various metabolic pathways of liver with special emphasize on lipid and carbohydrate metabolism and long chain polyunsaturated fatty acid (PUFA) synthesis, both at gene and protein levels. The data were obtained to understand the effect of vitamin A deficiency on the expression status (both gene and protein levels) of some of the key factors involved in lipogenesis, fatty acid oxidation, triglyceride secretion, long chain PUFA, resolvin D1 synthesis, glucose transport and glycogen synthesis of liver, using modern biology tools, such as quantitative real-time PCR (RT-PCR) and immunoblotting techniques. This data article provides the supporting evidence to the article “Vitamin A deficiency suppresses high fructose-induced triglyceride synthesis and elevates resolvin D1 levels” [1] and therefore, these data may be referred back, for comprehensive understanding and interpretations and for future studies. PMID:26909377

  7. Fibroblast adhesion to recombinant tropoelastin expressed as a protein A-fusion protein.

    PubMed Central

    Grosso, L E; Parks, W C; Wu, L J; Mecham, R P

    1991-01-01

    A bovine tropoelastin cDNA encoding exons 15-36 that includes the elastin-receptor binding site was expressed in Escherichia coli as a fusion protein with Protein A from Staphylococcus aureus. After isolation of the fusion protein by affinity chromatography on Ig-Sepharose, the tropoelastin domain was separated from plasmid-pR1T2T-encoded Protein A (Protein A') by CNBr cleavage. Cell-adhesion assays demonstrated specific adhesion to the recombinant tropoelastin. Furthermore, the data indicate that interactions involving the bovine elastin receptor mediate nuchalligament fibroblast adhesion to the recombinant protein. In agreement with earlier studies of fibroblast chemotaxis to bovine tropoelastin, nuchal-ligament fibroblast adhesion demonstrated developmental regulation of the elastin receptor. Images Fig. 2. Fig. 3. PMID:1996952

  8. Altered surfactant protein A gene expression and protein metabolism associated with repeat exposure to inhaled endotoxin.

    PubMed

    George, Caroline L S; White, Misty L; O'Neill, Marsha E; Thorne, Peter S; Schwartz, David A; Snyder, Jeanne M

    2003-12-01

    Chronically inhaled endotoxin, which is ubiquitous in many occupational and domestic environments, can adversely affect the respiratory system resulting in an inflammatory response and decreased lung function. Surfactant-associated protein A (SP-A) is part of the lung innate immune system and may attenuate the inflammatory response in various types of lung injury. Using a murine model to mimic occupational exposures to endotoxin, we hypothesized that SP-A gene expression and protein would be elevated in response to repeat exposure to inhaled grain dust and to purified lipopolysaccharide (LPS). Our results demonstrate that repeat exposure to inhaled endotoxin, either in the form of grain dust or purified LPS, results in increased whole lung SP-A gene expression and type II alveolar epithelial cell hyperplasia, whereas SP-A protein levels in lung lavage fluid are decreased. Furthermore, these alterations in SP-A gene activity and protein metabolism are dependent on an intact endotoxin signaling system. PMID:12922979

  9. Serum protein-expression profiling using the ProteinChip biomarker system.

    PubMed

    Gilbert, Kate; Figueredo, Sharel; Meng, Xiao-Ying; Yip, Christine; Fung, Eric T

    2004-01-01

    Protein-expression profiling of serum is a common approach to the discovery of potential diagnostic and therapeutic markers of disease. Like any other proteome, the serum proteome is characterized by protein expression across a large dynamic range. This single facet requires the employment of fractionation procedures prior to detection of protein. The authors use a combination of conventional column chromatography with array-based chromatography to simplify the serum proteome into subproteomes, thus providing a greater representation of the serum proteome. Robotics is employed to increase the throughput of sample processing. These procedures result in large amounts of data that are analyzed through a series of preprocessing and postprocessing steps. A well-designed serum profiling project can therefore result in the discovery of statistically sound, clinically meaningful protein biomarkers. PMID:15020796

  10. Differential expression of ribosomal proteins in myelodysplastic syndromes.

    PubMed

    Rinker, Elizabeth B; Dueber, Julie C; Qualtieri, Julianne; Tedesco, Jason; Erdogan, Begum; Bosompem, Amma; Kim, Annette S

    2016-02-01

    Aberrations of ribosomal biogenesis have been implicated in several congenital bone marrow failure syndromes, such as Diamond-Blackfan anaemia, Shwachman-Diamond syndrome and Dyskeratosis Congenita. Recent studies have identified haploinsufficiency of RPS14 in the acquired bone marrow disease isolated 5q minus syndrome, a subtype of myelodysplastic syndromes (MDS). However, the expression of various proteins comprising the ribosomal subunits and other proteins enzymatically involved in the synthesis of the ribosome has not been explored in non-5q minus MDS. Furthermore, differences in the effects of these expression alterations among myeloid, erythroid and megakaryocyte lineages have not been well elucidated. We examined the expression of several proteins related to ribosomal biogenesis in bone marrow biopsy specimens from patients with MDS (5q minus patients excluded) and controls with no known myeloid disease. Specifically, we found that there is overexpression of RPS24, DKC1 and SBDS in MDS. This overexpression is in contrast to the haploinsufficiency identified in the congenital bone marrow failure syndromes and in acquired 5q minus MDS. Potential mechanisms for these differences and aetiology for these findings in MDS are discussed. PMID:26408650

  11. Evaluation of TPGS-modified thermo-sensitive Pluronic PF127 hydrogel as a potential carrier to reverse the resistance of P-gp-overexpressing SMMC-7721 cell lines.

    PubMed

    Gao, Lei; Wang, Xiaoqing; Ma, Jianli; Hao, Daifeng; Wei, Pei; Zhou, Liang; Liu, Guiyang

    2016-04-01

    In the present studies locally injectable docetaxel nanocrystals loaded d-alpha tocopheryl polyethylene glycol 1000 succinate-modified Pluronic F127 (DOC-NCs-TPGS-PF127) thermo-sensitive hydrogels were prepared to reverse drug resistance of P-glycoprotein (P-gp)-overexpressing human liver cancer SMMC-7721 tumors. Firstly, DOC nanosuspensions with mean particle size of 196nm were prepared and dispersed into series of mixed solutions containing PF127 and TPGS of different ratios to obtain DOC-NCs-TPGS-PF127 hydrogels. DOC NCs, exhibiting a uniform distribution and very good physical stability during three sol-gel cycles in the hydrogel network, did not influence the gelation temperature. Swelling-dependent release pattern was found for DOC NCs from hydrogels and release profiles could be well fitted by the Peppas equation. MTT test showed that hydrogels containing 0% or 0.1% TPGS had no cytotoxicity against L929 fibroblasts. Both DOC solution and DOC-NCs-TPGS-PF127 hydrogels exhibited obvious cytotoxicity against sensitive SMMC-7721 cells. When resistant SMMC7721 cells were treated, DOC-NCs-TPGS-PF127 hydrogels showed significantly higher cytotoxicity compared with DOC solution and hydrogels containing no TPGS (DOC-NCs-PF127), with markedly lower IC50 and resistant index (RI). After intratumoral injection in SMMC-7721/RT tumor xenograft Balb/c mice model, DOC-NCs-TPGS-PF127 hydrogels exhibited about 5-fold increase and 1.8-fold increase in the inhibition rate of tumor growth compared with intravenous and intratumoral injection of DOC solution, respectively. It could be concluded that TPGS-modified PF127 thermo-sensitive hydrogel was an excellent locally injectable carrier to reverse P-gp overexpression associated multi-drug resistance. PMID:26764117

  12. Proteomic analysis of the differentially expressed proteins by airborne nanoparticles.

    PubMed

    Park, Seul Ki; Jeon, Yu Mi; Son, Bu Soon; Youn, Hyung Sun; Lee, Mi Young

    2011-07-01

    Airborne nanoparticles with thermodynamic diameters less than 56 nm (PM(0.056)) were collected using a Moudi cascade impactor, and the differentially expressed proteins upon exposure to the airborne nanoparticles were identified in human bronchial epithelial cells. More than 600 protein spots were detected on the two-dimensional gel, and the identified 13 of these proteins showed notable changes. Nine were up-regulated and four were down-regulated following treatment with the airborne nanoparticles. Notably, malignant transformation-associated multiple forms of keratins, epigenetic regulation-related MBD1-containing chromatin associated factor 2, epithelial malignancy-related vimentin and exocytosis-related annexin A2 were changed upon exposure to airborne nanoparticle PM(0.056). PMID:21491466

  13. Mechanism of expression of the rat HCNP precursor protein gene.

    PubMed

    Tohdoh, N; Tojo, S; Kimura, M; Ishii, T; Ojika, K

    1997-04-01

    The hippocampal cholinergic neurostimulating peptide (HCNP), isolated from hippocampal tissue of 10- to 12-day-old rats, enhances the in vitro synthesis of acetylcholine in medial septal tissue explants. The HCNP precursor is a 21 kDa protein that binds hydrophobic ligands and Mg-ATP, and is associated with the opioid-binding protein. We employed an HCNP-precursor cDNA as probe to clone the genomic DNA, used for mapping of the exon-intron structure of the gene. We also determined the nucleotide structure of the promoter region of the rat HCNP precursor protein gene. By using S1 mapping and CAT as a reporter, we found multiple promoters that were aligned in the 5' untranslated region. In addition, the presence of several putative enhancer binding sequences were tested by electrophoresis mobility shift assays. Northern blot analysis revealed that the gene is expressed in a variety of rat tissues and various subregions of the brain. These results suggest that HCNP-precursor gene expression is regulated by a general transactivation factor such as SP1, and that the specific presence of the bioactive HCNP in certain tissues results from post-translational events such as proteolytic processing of the precursor protein, which takes place predominantly in the hippocampus of young rats. PMID:9105667

  14. Grizzly bear corticosteroid binding globulin: Cloning and serum protein expression.

    PubMed

    Chow, Brian A; Hamilton, Jason; Alsop, Derek; Cattet, Marc R L; Stenhouse, Gordon; Vijayan, Mathilakath M

    2010-06-01

    Serum corticosteroid levels are routinely measured as markers of stress in wild animals. However, corticosteroid levels rise rapidly in response to the acute stress of capture and restraint for sampling, limiting its use as an indicator of chronic stress. We hypothesized that serum corticosteroid binding globulin (CBG), the primary transport protein for corticosteroids in circulation, may be a better marker of the stress status prior to capture in grizzly bears (Ursus arctos). To test this, a full-length CBG cDNA was cloned and sequenced from grizzly bear testis and polyclonal antibodies were generated for detection of this protein in bear sera. The deduced nucleotide and protein sequences were 1218 bp and 405 amino acids, respectively. Multiple sequence alignments showed that grizzly bear CBG (gbCBG) was 90% and 83% identical to the dog CBG nucleotide and amino acid sequences, respectively. The affinity purified rabbit gbCBG antiserum detected grizzly bear but not human CBG. There were no sex differences in serum total cortisol concentration, while CBG expression was significantly higher in adult females compared to males. Serum cortisol levels were significantly higher in bears captured by leg-hold snare compared to those captured by remote drug delivery from helicopter. However, serum CBG expression between these two groups did not differ significantly. Overall, serum CBG levels may be a better marker of chronic stress, especially because this protein is not modulated by the stress of capture and restraint in grizzly bears. PMID:20347821

  15. Gi/o proteins: expression for direct activation enquiry.

    PubMed

    Di Cesare Mannelli, Lorenzo; Pacini, Alessandra; Toscano, Annarita; Fortini, Martina; Berti, Debora; Ghelardini, Carla; Galeotti, Nicoletta; Baglioni, Piero; Bartolini, Alessandro

    2006-05-01

    G protein-mediated pathways are fundamental mechanisms of cell signaling. In this paper, the expression and the characterization of the alphai1, alphai3, alphao1, beta1, and gamma2 subunits of the human G protein are described. This approach was developed to evaluate the G protein activation profile of new compounds. pCR-TOPO T7 vectors, engineered to contain the target sequences, were used to transform Escherichia coli competent cells. Subunits were over-expressed in a preparative scale as fusion proteins with a six-histidine tag, and subsequently purified by metal chelate chromatography. Afterward, the His-tag was removed by enterokinase digestion, and the secondary structures of the recombinant subunits were analyzed by circular dichroism. To assess the functionality of the subunits, the rate of GTP hydrolysis and GTPgammaS binding were evaluated both in the absence and in the presence of two modulators: the peptidic activator Mastoparan and the non-peptidic activator N-dodecyl-lysinamide (ML250). Tests were conducted on isolated alpha-subunit and on heterotrimeric alphabetagamma complex, alone or reconstituted in phospholipidic vesicles. Our results show that recombinant subunits are stable, properly folded and, fully active, which makes them suitable candidates for functional studies. PMID:16364655

  16. Expression cloning of genes encoding human peroxisomal proteins

    SciTech Connect

    Spathaky, J.M.; Tate, A.W.; Cox, T.M.

    1994-09-01

    Numerous metabolic disorders associated with diverse peroxisomal defects have been identified but their molecular characterization has been hampered by difficulties associated with the purification of proteins from this fragile organelle. We have utilized antibodies directed against the C-terminal tripeptide peroxisomal targeting signal to detect hitherto unknown peroxisomal proteins in tissue fractions and to isolate genes encoding peroxisonal proteins from human expression libraries. We immunized rabbits with a peptide conjugate encompassing the C-terminal nine amino acids of rat peroxisomal acyl CoA oxidase. Immunoprecipitation assays using radio-labelled peptide showed that the antibody specifically recognizes the terminal SKL motif as well as C-terminal SHL and SRL but not SHL at an internal position. Affinity-purified antibody was used to probe Western blots of crude and peroxisome-enriched monkey liver preparations and detected 8-10 proteins specifically in the peroxisome fractions. 100 positive clones were identified on screening a human liver cDNA expression library in {lambda}-gt11. Sequence analysis has confirmed the identity of cDNA clones for human acyl CoA oxidase and epoxide hydrolase. Four clones show no sequence identity and their putative role in the human peroxisome is being explored.

  17. Regulation of RAG-2 protein expression in avian thymocytes.

    PubMed Central

    Ferguson, S E; Accavitti, M A; Wang, D D; Chen, C L; Thompson, C B

    1994-01-01

    The recombinase-activating genes, RAG-1 and RAG-2, have been shown to be necessary to initiate the process of V(D)J recombination during the ontogeny of lymphocytes. While much is known about the end products of this rearrangement process, little is known about the function or regulation of the components of the recombinase system. To this end, we have generated a monoclonal antibody to the chicken RAG-2 protein. Chicken thymocytes were found to express high levels of RAG-2, part of which is phosphorylated. Within thymocytes, RAG-2 is expressed primarily within the nucleus. RAG-2 protein levels are high in the CD4- CD8- and CD4+ CD8+ immature thymocytes but absent at the single-positive CD4+ CD8- or CD4- CD8+ stage of thymocyte development. Mitogenic stimulation of thymocytes with phorbol myristate acetate and ionomycin results in down-regulation of RAG-2 expression. Consistent with these data, in vivo levels of RAG-2 are markedly lower in proliferating thymocytes than in smaller, G0/G1 cells. Down-regulation of RAG-2 expression appears to occur before cells enter S phase, suggesting that RAG-2 function may be limited to noncycling cells. Images PMID:7935443

  18. Expression pattern of Protein Kinase C ϵ during mouse embryogenesis

    PubMed Central

    2013-01-01

    Background Protein kinase C epsilon (PKCϵ) belongs to the novel PKC subfamily, which consists of diacylglycerol dependent- and calcium independent-PKCs. Previous studies have shown that PKCϵ is important in different contexts, such as wound healing or cancer. In this study, we contribute to expand the knowledge on PKCϵ by reporting its expression pattern during murine midgestation using the LacZ reporter gene and immunostaining procedures. Results Sites showing highest PKCϵ expression were heart at ealier stages, and ganglia in older embryos. Other stained domains included somites, bone, stomach, kidney, and blood vessels. Conclusions The seemingly strong expression of PKCϵ in heart and ganglia shown in this study suggests a important role of this isoform in the vascular and nervous systems during mouse development. However, functional redundancy with other PKCs during midgestation within these domains and others reported here possibly exists since PKCϵ deficient mice do not display obvious embryonic developmental defects. PMID:23639204

  19. Mutational Analysis of the Rift Valley Fever Virus Glycoprotein Precursor Proteins for Gn Protein Expression.

    PubMed

    Phoenix, Inaia; Lokugamage, Nandadeva; Nishiyama, Shoko; Ikegami, Tetsuro

    2016-01-01

    The Rift Valley fever virus (RVFV) M-segment encodes the 78 kD, NSm, Gn, and Gc proteins. The 1st AUG generates the 78 kD-Gc precursor, the 2nd AUG generates the NSm-Gn-Gc precursor, and the 3rd AUG makes the NSm'-Gn-Gc precursor. To understand biological changes due to abolishment of the precursors, we quantitatively measured Gn secretion using a reporter assay, in which a Gaussia luciferase (gLuc) protein is fused to the RVFV M-segment pre-Gn region. Using the reporter assay, the relative expression of Gn/gLuc fusion proteins was analyzed among various AUG mutants. The reporter assay showed efficient secretion of Gn/gLuc protein from the precursor made from the 2nd AUG, while the removal of the untranslated region upstream of the 2nd AUG (AUG2-M) increased the secretion of the Gn/gLuc protein. Subsequently, recombinant MP-12 strains encoding mutations in the pre-Gn region were rescued, and virological phenotypes were characterized. Recombinant MP-12 encoding the AUG2-M mutation replicated slightly less efficiently than the control, indicating that viral replication is further influenced by the biological processes occurring after Gn expression, rather than the Gn abundance. This study showed that, not only the abolishment of AUG, but also the truncation of viral UTR, affects the expression of Gn protein by the RVFV M-segment. PMID:27231931

  20. Mutational Analysis of the Rift Valley Fever Virus Glycoprotein Precursor Proteins for Gn Protein Expression

    PubMed Central

    Phoenix, Inaia; Lokugamage, Nandadeva; Nishiyama, Shoko; Ikegami, Tetsuro

    2016-01-01

    The Rift Valley fever virus (RVFV) M-segment encodes the 78 kD, NSm, Gn, and Gc proteins. The 1st AUG generates the 78 kD-Gc precursor, the 2nd AUG generates the NSm-Gn-Gc precursor, and the 3rd AUG makes the NSm’-Gn-Gc precursor. To understand biological changes due to abolishment of the precursors, we quantitatively measured Gn secretion using a reporter assay, in which a Gaussia luciferase (gLuc) protein is fused to the RVFV M-segment pre-Gn region. Using the reporter assay, the relative expression of Gn/gLuc fusion proteins was analyzed among various AUG mutants. The reporter assay showed efficient secretion of Gn/gLuc protein from the precursor made from the 2nd AUG, while the removal of the untranslated region upstream of the 2nd AUG (AUG2-M) increased the secretion of the Gn/gLuc protein. Subsequently, recombinant MP-12 strains encoding mutations in the pre-Gn region were rescued, and virological phenotypes were characterized. Recombinant MP-12 encoding the AUG2-M mutation replicated slightly less efficiently than the control, indicating that viral replication is further influenced by the biological processes occurring after Gn expression, rather than the Gn abundance. This study showed that, not only the abolishment of AUG, but also the truncation of viral UTR, affects the expression of Gn protein by the RVFV M-segment. PMID:27231931

  1. Expression of odorant-binding proteins and chemosensory proteins in some Hymenoptera.

    PubMed

    Calvello, M; Brandazza, A; Navarrini, A; Dani, F R; Turillazzi, S; Felicioli, A; Pelosi, P

    2005-04-01

    The expression of chemosensory proteins (CSPs) and odorant-binding proteins (OBPs) in individuals of different castes and ages have been monitored in three species of social hymenopterans, Polistes dominulus (Hymenoptera, Vespidae), Vespa crabro (Hymenoptera, Vespidae) and Apis mellifera (Hymenoptera, Apidae), using PCR with specific primers and polyclonal antibodies. In the paper wasp P. dominulus, OBP is equally expressed in antennae, wings and legs of all castes and ages, while CSP is often specifically present in antennae and in some cases also in legs. In the vespine species V. crabro CSP is antennal specific, while OBP is also expressed in legs and wings. The three CSPs and the five OBPs of A. mellifera show a complex pattern of expression, where both classes of proteins include members specifically expressed in antennae and others present in other parts of the body. These data indicate that at least in some hymenopteran species CSPs are specifically expressed in antennae and could perform roles in chemosensory perception so far assigned only to OBPs. PMID:15763466

  2. Unique expression of cytoskeletal proteins in human soft palate muscles.

    PubMed

    Shah, Farhan; Berggren, Diana; Holmlund, Thorbjörn; Levring Jäghagen, Eva; Stål, Per

    2016-03-01

    The human oropharyngeal muscles have a unique anatomy with diverse and intricate functions. To investigate if this specialization is also reflected in the cytoarchitecture of muscle fibers, intermediate filament proteins and the dystrophin-associated protein complex have been analyzed in two human palate muscles, musculus uvula (UV) and musculus palatopharyngeus (PP), with immunohistochenmical and morphological techniques. Human limb muscles were used as reference. The findings show that the soft palate muscle fibers have a cytoskeletal architecture that differs from the limb muscles. While all limb muscles showed immunoreaction for a panel of antibodies directed against different domains of cytoskeletal proteins desmin and dystrophin, a subpopulation of palate muscle fibers lacked or had a faint immunoreaction for desmin (UV 11.7% and PP 9.8%) and the C-terminal of the dystrophin molecule (UV 4.2% and PP 6.4%). The vast majority of these fibers expressed slow contractile protein myosin heavy chain I. Furthermore, an unusual staining pattern was also observed in these fibers for β-dystroglycan, caveolin-3 and neuronal nitric oxide synthase nNOS, which are all membrane-linking proteins associated with the dystrophin C-terminus. While the immunoreaction for nNOS was generally weak or absent, β-dystroglycan and caveolin-3 showed a stronger immunostaining. The absence or a low expression of cytoskeletal proteins otherwise considered ubiquitous and important for integration and contraction of muscle cells indicate a unique cytoarchitecture designed to meet the intricate demands of the upper airway muscles. It can be concluded that a subgroup of muscle fibers in the human soft palate appears to have special biomechanical properties, and their unique cytoarchitecture must be taken into account while assessing function and pathology in oropharyngeal muscles. PMID:26597319

  3. Amyloid Precursor Protein Expression Modulates Intestine Immune Phenotype

    PubMed Central

    Puig, Kendra L.; Swigost, Adam J.; Zhou, Xudong; Sens, MaryAnn; Combs, Colin K.

    2014-01-01

    Amyloid precursor protein (APP) is widely expressed across many tissue and cell types. Proteolytic processing of the protein gives rise to a plethora of protein fragments with varied biological activities. Although a large amount of data has been generated describing the metabolism of the protein in neurons, its role in regulating the phenotype of other cells remains unclear. Based upon prior work demonstrating that APP regulates the activation phenotype of monocytic lineage cells, we hypothesized that APP can regulate macrophage activation phenotype in tissues other than brain. Ileums of the small intestines from C57BL6/J wild type and APP−/− mice were compared as a representative tissue normally associated with abundant macrophage infiltration. APP−/− intestines demonstrated diminished CD68 immunoreactivity compared to wild type mice. This correlated with significantly less cycloxygenase-2 (cox-2), CD68, CD40, CD11c, and βIII-tubulin protein levels. Peritoneal macrophage from APP−/− mice demonstrated decreased in vitro migratory ability compared to wild type cells and diminished basal KC cytokine secretion. Whereas, APP−/− intestinal macrophage had an increase in basal KC cytokine secretion compared to wild type cells. Conversely, there was a significant decrease in multiple cytokine levels in APP−/− compared to wild type ileums. Finally, APP−/− mice demonstrated impaired absorption and increased motility compared to wild type mice. These data demonstrate the APP expression regulates immune cell secretions and phenotype and intestinal function. This data set describes a novel function for this protein or its metabolites that may be relevant not only for Alzheimer’s disease but a range of immune-related disorders. PMID:22124967

  4. Expression and Localization of Lung Surfactant Proteins in Human Testis

    PubMed Central

    Wagner, Walter; Matthies, Cord; Ruf, Christian; Hartmann, Arndt; Garreis, Fabian; Paulsen, Friedrich

    2015-01-01

    Background Surfactant proteins (SPs) have been described in various tissues and fluids including tissues of the nasolacrimal apparatus, airways and digestive tract. Human testis have a glandular function as a part of the reproductive and the endocrine system, but no data are available on SPs in human testis and prostate under healthy and pathologic conditions. Objective The aim of the study was the detection and characterization of the surfactant proteins A, B, C and D (SP-A, SP-B, SP-C, SP-D) in human testis. Additionally tissue samples affected by testicular cancer were investigated. Results Surfactant proteins A, B, C and D were detected using RT-PCR in healthy testis. By means of Western blot analysis, these SPs were detected at the protein level in normal testis, seminoma and seminal fluid, but not in spermatozoa. Expression of SPs was weaker in seminoma compared to normal testicular tissue. SPs were localized in combination with vimentin immunohistochemically in cells of Sertoli and Leydig. Conclusion Surfactant proteins seem to be inherent part of the human testis. By means of physicochemical properties the proteins appear to play a role during immunological and rheological process of the testicular tissue. The presence of SP-B and SP-C in cells of Sertoli correlates with their function of fluid secretion and may support transportation of spermatozoa. In seminoma the expression of all SP's was generally weaker compared to normal germ cells. This could lead to a reduction of immunomodulatory and rheology processes in the germ cell tumor. PMID:26599233

  5. Identification of differentially expressed serum proteins in gastric adenocarcinoma☆

    PubMed Central

    Subbannayya, Yashwanth; Mir, Sartaj Ahmad; Renuse, Santosh; Manda, Srikanth S.; Pinto, Sneha M.; Puttamallesh, Vinuth N.; Solanki, Hitendra Singh; Manju, H.C.; Syed, Nazia; Sharma, Rakesh; Christopher, Rita; Vijayakumar, M.; Kumar, K.V. Veerendra; Prasad, T.S. Keshava; Ramaswamy, Girija; Kumar, Rekha V.; Chatterjee, Aditi; Pandey, Akhilesh; Gowda, Harsha

    2015-01-01

    Gastric adenocarcinoma is an aggressive cancer with poor prognosis. Blood based biomarkers of gastric cancer have the potential to improve diagnosis and monitoring of these tumors. Proteins that show altered levels in the circulation of gastric cancer patients could prove useful as putative biomarkers. We used an iTRAQ-based quantitative proteomic approach to identify proteins that show altered levels in the sera of patients with gastric cancer. Our study resulted in identification of 643 proteins, of which 48 proteins showed increased levels and 11 proteins showed decreased levels in serum from gastric cancer patients compared to age and sex matched healthy controls. Proteins that showed increased expression in gastric cancer included inter-alpha-trypsin inhibitor heavy chain H4 (ITIH4), Mannose-binding protein C (MBL2), sex hormone-binding globulin (SHBG), insulin-like growth factor-binding protein 2 (IGFBP2), serum amyloid A protein (SAA1), Orosomucoid 1 (ORM1) and extracellular superoxide dismutase [Cu–Zn] (SOD3). We used multiple reaction monitoring assays and validated elevated levels of ITIH4 and SAA1 proteins in serum from gastric cancer patients. Biological significance Gastric cancer is a highly aggressive cancer associated with high mortality. Serum-based biomarkers are of considerable interest in diagnosis and monitoring of various diseases including cancers. Gastric cancer is often diagnosed at advanced stages resulting in poor prognosis and high mortality. Pathological diagnosis using biopsy specimens remains the gold standard for diagnosis of gastric cancer. Serum-based biomarkers are of considerable importance as they are minimally invasive. In this study, we carried out quantitative proteomic profiling of serum from gastric cancer patients to identify proteins that show altered levels in gastric cancer patients. We identified more than 50 proteins that showed altered levels in gastric cancer patient sera. Validation in a large cohort of well

  6. Constraints imposed by nonfunctional protein-protein interactions on gene expression and proteome size

    NASA Astrophysics Data System (ADS)

    Zhang, Jingshan; Maslov, Sergei; Shakhnovich, Eugene

    2009-03-01

    Crowded intracellular environments present a challenge for proteins to form functional specific complexes while reducing nonfunctional interactions with promiscuous nonfunctional partners. Here we show how nonfunctional interactions limit the proteome diversity and the average concentration of co-expressed and co-localized proteins. We use yeast compartments to verify our hypothesis that the yeast proteome has evolved to operate closely to the upper limit of its size, while keeping individual protein concentrations sufficiently low to reduce nonfunctional interactions. These findings have implication for conceptual understanding of intracellular compartmentalization, multicellularity, and differentiation.

  7. A systematic approach for testing expression of human full-length proteins in cell-free expression systems

    PubMed Central

    Langlais, Claudia; Guilleaume, Birgit; Wermke, Nadja; Scheuermann, Tina; Ebert, Lars; LaBaer, Joshua; Korn, Bernhard

    2007-01-01

    Background The growing field of proteomics and systems biology is resulting in an ever increasing demand for purified recombinant proteins for structural and functional studies. Here, we show a systematic approach to successfully express a full-length protein of interest by using cell-free and cell-based expression systems. Results In a pre-screen, we evaluated the expression of 960 human full-length open reading frames in Escherichia coli (in vivo and in vitro). After analysing the protein expression rate and solubility, we chose a subset of 87 plasmids yielding no protein product in E. coli in vivo. These targets were subjected to a more detailed analysis comparing a prokaryotic cell-free E. coli system with an eukaryotic wheat germ system. In addition, we determined the expression rate, yield and solubility of those proteins. After sequence optimisation for the E. coli in vitro system and generating linear templates for wheat germ expression, the success rate of cell-free protein expression reached 93%. Conclusion We have demonstrated that protein expression in cell-free systems is an appropriate technology for the successful expression of soluble full-length proteins. In our study, wheat germ expression using a two compartment system is the method of choice as it shows high solubility and high protein yield. PMID:17915018

  8. [Proteins in cancer multidrug resistance].

    PubMed

    Popęda, Marta; Płuciennik, Elżbieta; Bednarek, Andrzej K

    2014-01-01

    Multidrug Resistance (MDR) is defined as insensitivity to administered medicines that are structurally unrelated and have different molecular targets. Cancers possess numerous mechanisms of drug resistance, involving various aspects of cell biology. A pivotal role in this phenomenon is played by proteins--enzymatic or structural parts of the cell. Membrane transporters, including the main members of ABC protein family--P-gp, MRP1 and BCRP, as well as LRP, which builds structure of vaults, determine the multidrug-resistant phenotype by decreasing drug concentration within the cell or modifying its distribution to intracellular compartments. The π isoform of protein enzyme--glutathione S-transferase (GSTP-1), is responsible for excessive intensity of detoxification of cytostatics. A common example of altered drug target site that does not respond to chemotherapy is topoisomerase II α (TopoIIa). Alterations of programmed cell death result from expression of metallothionein (MT)--inhibitor of the process, and cytokeratin 18 (CK18), which, if in high concentration, also prevents apoptosis of cells. Several methods of decreasing activity of these proteins have been developed, aiming to overcome MDR in cancer cells. However, for a variety of reasons, their clinical suitability is still very low, leading to continuous increase in death rate among patients. This paper presents current state of knowledge on the most important examples of proteins responsible for MDR of cancer cells and molecular mechanisms of their action. PMID:24864112

  9. Optimizing Escherichia coli as a protein expression platform to produce Mycobacterium tuberculosis immunogenic proteins

    PubMed Central

    2013-01-01

    Background A number of valuable candidates as tuberculosis vaccine have been reported, some of which have already entered clinical trials. The new vaccines, especially subunit vaccines, need multiple administrations in order to maintain adequate life-long immune memory: this demands for high production levels and degree of purity. Results In this study, TB10.4, Ag85B and a TB10.4-Ag85B chimeric protein (here-after referred as full) - immunodominant antigens of Mycobacterium tuberculosis - were expressed in Escherichia coli and purified to homogeneity. The rational design of expression constructs and optimization of fermentation and purification conditions allowed a marked increase in solubility and yield of the recombinant antigens. Indeed, scaling up of the process guaranteed mass production of all these three antigens (2.5-25 mg of pure protein/L cultivation broth). Quality of produced soluble proteins was evaluated both by mass spectrometry to assess the purity of final preparations, and by circular dichroism spectroscopy to ascertain the protein conformation. Immunological tests of the different protein products demonstrated that when TB10.4 was fused to Ag85B, the chimeric protein was more immunoreactive than either of the immunogenic protein alone. Conclusions We reached the goal of purifying large quantities of soluble antigens effective in generating immunological response against M. tuberculosis by a robust, controlled, scalable and economically feasible production process. PMID:24252280

  10. Expression of proteoglycan core proteins in human bone marrow stroma.

    PubMed Central

    Schofield, K P; Gallagher, J T; David, G

    1999-01-01

    Heparan sulphate proteoglycans (HSPGs) present on the surface of bone marrow stromal cells and in the extracellular matrix (ECM) have important roles in the control of adhesion and growth of haemopoietic stem and progenitor cells. The two main groups of proteoglycans which contain heparan sulphate chains are members of the syndecan and glypican families. In this study we have identified the main surface membrane and matrix-associated HSPGs present in normal human bone marrow stroma formed in long-term culture. Proteoglycans were extracted from the adherent stromal layers and treated with heparitinase and chondroitinase ABC. The core proteins were detected by Western blotting using antibodies directed against syndecans-1-4, glypican-1 and the ECM HSPG, perlecan. Stromal cell expression at the RNA level was detected by Northern blotting and by reverse transcription PCR. Glypican-1, syndecan-3 and syndecan-4 were the major cell-membrane HSPG species and perlecan was the major ECM proteoglycan. There was no evidence for expression of syndecan-1 protein. Syndecan-3 was expressed mainly as a variant or processed 50-55 kDa core protein and in lower amounts as the characteristic 125 kDa core protein. These results suggest that syndecan-3, syndecan-4 and glypican-1 present on the surface of marrow stromal cells, together with perlecan in the ECM, may be responsible for creating the correct stromal 'niche' for the maintenance and development of haemopoietic stem and progenitor cells. The detection of a variant form of syndecan-3 as a major stromal HSPG suggests a specific role for this syndecan in haemopoiesis. PMID:10527946

  11. Protein expression and characterization of SEP3 from Arabidopsis thaliana.

    PubMed

    Shi, Q; Zhou, J; Wang, P; Lin, X; Xu, Y

    2015-01-01

    SEPALLATA (SEP) MADS-box genes play crucial roles in the regulation of floral growth and development. They are required for the specification of sepals, petals, stamens, and carpels as well as for floral determinacy. SEPs perform their functions through the formation of homo- or hetero-polymers, which are the molecular basis of floral quartets. In vitro assays indicated that SEP3 forms a tetramer after binding to DNA, but it is unclear whether DNA binding induces the tetramer, because SEP3 is often reported to form a dimer. Here, we analyzed the oligomeric status of SEP3 domains in the absence of the DNA-binding MADS-box domain. The truncated SEP3 was constructed as a fusion protein and expressed in prokaryotic cells. The purified protein fragment displayed as a tetramer in the size exclusion chromatographic column, and a glutaraldehyde cross-linking assay demonstrated that the protein contained a dimer unit. Yeast two-hybrid tests further verified that the fragments form homologous polymers in vivo, and that the K domain is involved in tetramer formation. Current results imply that the SEP3 protein regulates the formation of flower meristems using the tetramer as a unit, and that the DNA-binding MADS-box is dispensable for polymer formation. The C-terminal region does not contribute to homo-tetramer formation, but it may be reserved to glue other proteins. PMID:26505403

  12. Preliminary identification of differentially expressed tear proteins in keratoconus

    PubMed Central

    Wasinger, Valerie C.; Pye, David C.; Willcox, Mark D. P.

    2013-01-01

    Purpose To examine the proteins differentially expressed in the tear film of people with keratoconus and normal subjects. Methods Unstimulated tears from people with keratoconus (KC) and controls (C) were collected using a capillary tube. Tear proteins from people with KC and controls were partitioned using a novel in-solution electrophoresis, Microflow 10 (ProteomeSep), and analyzed using linear ion trap quadrupole fourier transform mass spectrometry. Spectral counting was used to quantify the individual tear proteins. Results Elevated levels of cathepsin B (threefold) were evident in the tears of people with KC. Polymeric immunoglobulin receptor (ninefold), fibrinogen alpha chain (eightfold), cystatin S (twofold), and cystatin SN (twofold) were reduced in tears from people with KC. Keratin type-1 cytoskeletal-14 and keratin type-2 cytoskeletal-5 were present only in the tears of people with KC. Conclusions The protein changes in tears, that is, the decrease in protease inhibitors and increase in proteases, found in the present and other previously published studies reflect the pathological events involved in KC corneas. Further investigations into tear proteins may help elucidate the underlying molecular mechanisms of KC, which could result in better treatment options. PMID:24194634

  13. Protein expression strategies in Tobacco necrosis virus-D.

    PubMed

    Chkuaseli, Tamari; Newburn, Laura R; Bakhshinyan, David; White, K Andrew

    2015-12-01

    Tobacco necrosis virus (TNV-D) has a plus-strand RNA genome that is neither 5' capped nor 3' poly-adenylated. Instead, it utilizes a 3' cap-independent translational enhancer (3'CITE) located in its 3' untranslated region (UTR) for translation of its proteins. We have examined the protein expression strategies used by TNV-D and our results indicate that: (i) a base pairing interaction between conserved ACCA and UGGU motifs in the genomic 5'UTR and 3'CITE, respectively, is not required for efficient plant cell infection, (ii) similar potential 5'UTR-3'CITE interactions in the two viral subgenomic mRNAs are not needed for efficient translation of viral proteins in vitro, (iii) a small amount of capsid protein is translated from the viral genome by a largely 3'CITE-independent mechanism, (iv) the larger of two possible forms of capsid protein is efficiently translated, and (v) p7b is translated from subgenomic mRNA1 by a leaky scanning mechanism. PMID:26402375

  14. Protein body formation in stable transgenic tobacco expressing elastin-like polypeptide and hydrophobin fusion proteins

    PubMed Central

    2013-01-01

    Background Plants are recognized as an efficient and inexpensive system to produce valuable recombinant proteins. Two different strategies have been commonly used for the expression of recombinant proteins in plants: transient expression mediated by Agrobacterium; or stable transformation of the plant genome. However, the use of plants as bioreactors still faces two main limitations: low accumulation levels of some recombinant proteins and lack of efficient purification methods. Elastin-like polypeptide (ELP), hydrophobin I (HFBI) and Zera® are three fusion partners found to increase the accumulation levels of recombinant proteins and induce the formation of protein bodies (PBs) in leaves when targeted to the endoplasmic reticulum (ER) in transient expression assays. In this study the effects of ELP and HFBI fusion tags on recombinant protein accumulation levels and PB formation was examined in stable transgenic Nicotiana tabacum. Results The accumulation of recombinant protein and PB formation was evaluated in two cultivars of Nicotiana tabacum transformed with green fluorescent protein (GFP) fused to ELP or HFBI, both targeted and retrieved to the ER. The ELP and HFBI tags increased the accumulation of the recombinant protein and induced the formation of PBs in leaves of stable transgenic plants from both cultivars. Furthermore, these tags induced the formation of PBs in a concentration-dependent manner, where a specific level of recombinant protein accumulation was required for PBs to appear. Moreover, agro-infiltration of plants accumulating low levels of recombinant protein with p19, a suppressor of post-transcriptional gene silencing (PTGS), increased accumulation levels in four independent transgenic lines, suggesting that PTGS might have caused the low accumulation levels in these plants. Conclusion The use of ELP and HFBI tags as fusion partners in stable transgenic plants of tobacco is feasible and promising. In a constitutive environment, these tags

  15. Blue Light Modulates Murine Microglial Gene Expression in the Absence of Optogenetic Protein Expression

    PubMed Central

    Cheng, Kevin P.; Kiernan, Elizabeth A.; Eliceiri, Kevin W.; Williams, Justin C.; Watters, Jyoti J.

    2016-01-01

    Neural optogenetic applications over the past decade have steadily increased; however the effects of commonly used blue light paradigms on surrounding, non-optogenetic protein-expressing CNS cells are rarely considered, despite their simultaneous exposure. Here we report that blue light (450 nm) repetitively delivered in both long-duration boluses and rapid optogenetic bursts gene-specifically altered basal expression of inflammatory and neurotrophic genes in immortalized and primary murine wild type microglial cultures. In addition, blue light reduced pro-inflammatory gene expression in microglia activated with lipopolysaccharide. These results demonstrate previously unreported, off-target effects of blue light in cells not expressing optogenetic constructs. The unexpected gene modulatory effects of blue light on wild type CNS resident immune cells have novel and important implications for the neuro-optogenetic field. Further studies are needed to elucidate the molecular mechanisms and potential therapeutic utility of blue light modulation of the wild type CNS. PMID:26883795

  16. An engineered chaperonin caging a guest protein: Structural insights and potential as a protein expression tool

    PubMed Central

    Furutani, Masahiro; Hata, Jun-Ichi; Shomura, Yasuhito; Itami, Keisuke; Yoshida, Takao; Izumoto, Yoshitaka; Togi, Akiko; Ideno, Akira; Yasunaga, Takuo; Miki, Kunio; Maruyama, Tadashi

    2005-01-01

    The structure of a chaperonin caging a substrate protein is not quite clear. We made engineered group II chaperonins fused with a guest protein and analyzed their structural and functional features. Thermococcus sp. KS-1 chaperonin α-subunit (TCP) which forms an eightfold symmetric double-ring structure was used. Expression plasmids were constructed which carried two or four TCP genes ligated head to tail in phase and a target protein gene at the 3′ end of the linked TCP genes. Electron microscopy showed that the expressed gene products with the molecular sizes of ~120 kDa (di-TCP) and ~230 kDa (tetra-TCP) formed double-ring complexes similar to those of wild-type TCP. The tetra-TCP retained ATPase activity and its thermostability was significantly higher than that of the wild type. A 260-kDa fusion protein of tetra-TCP and green fluorescent protein (GFP, 27 kDa) was able to form the double-ring complexes with green fluorescence. Image analyses indicated that the GFP moiety of tetra-TCP/GFP fusion protein was accommodated in the central cavity, and tetra-TCP/GFP formed the closed-form similar to that crystallographically resolved in group II chaperonins. Furthermore, it was suggested that caging GFP expanded the cavity around the bottom. Using this tetra-TCP fusion strategy, two virus structural proteins (21–25 kDa) toxic to host cells or two antibody fragments (25–36 kDa) prone to aggregate were well expressed in the soluble fraction of Escherichia coli. These fusion products also assembled to double-ring complexes, suggesting encapsulation of the guest proteins. The antibody fragments liberated by site-specific protease digestion exhibited ligand-binding activities. PMID:15659368

  17. Expression of recombinant green fluorescent protein in Bacillus methanolicus.

    PubMed

    Nilasari, Dewi; Dover, Nir; Rech, Sabine; Komives, Claire

    2012-01-01

    Microbial biocatalysts are used in a wide range of industries to produce large scale quantities of proteins, amino acids, and commodity chemicals. While the majority of these processes use glucose or other low-cost sugars as the substrate, Bacillus methanolicus is one example of a biocatalyst that has shown sustained growth on methanol as a carbon source at elevated temperature (50-53°C optimum) resulting in reduced feed and utility costs. Specifically, the complete chemical process enabled by this approach takes methane from natural gas, and following a low-cost conversion to methanol, can be used for the production of high value products. In this study, production of recombinant green fluorescent protein (GFPuv) by B. methanolicus is explored. A plasmid was constructed that incorporates the methanol dehydrogenase (mdh) promoter of B. methanolicus MGA3 together with the GFPuv gene. The plasmid, pNW33N, was shown to be effective for expression in other Bacillus strains, although not previously in B. methanolicus. A published electroporation protocol for transformation of B. methanolicus was modified to result in expression of GFP using plasmid pNW33N-mdh-GFPuv (pNmG). Transformation was confirmed by both agarose gel electrophoresis and by observation of green fluorescence under UV light exposure. The mass yield of cells and protein were measured in shake flask experiments. The optimum concentration of methanol for protein production was found to be at 200 mM. Higher concentrations than 200 mM resulted in slightly higher biomass production but lower amounts of recombinant protein. PMID:22275315

  18. P53 protein expression in human leukemia and lymphoma cells.

    PubMed

    Koníková, E; Kusenda, J

    2001-01-01

    The purpose of this study was to determine the value of p53 protein overexpression in human leukemia and lymphoma cells. We examined PB and/or BM samples on a series of 111 patients with immunophenotypically defined hematological malignancies at diagnosis, in remission and in relapsed disease comparing to 20 control samples of healthy individuals. p53 protein has been studied by flow cytometry using three monoclonal antibodies specific for epitopes on N-terminus (Bp53-12, DO-1) and central region (DO-11) of p53 protein. Our findigs showed, that p53 expression may contribute to phenotype of leukemic cells and that overexpression of this protein is often associated with progression of disease. All samples of early B-ALL patients and samples of patients with immunophenotypically defined T- cell disorders examined at diagnosis of disease were p53 positive. Eleven of 19 patient samples from AML at diagnosis showed also increased expression of p53 protein. The cells of all patients who responded to therapy with complete immunophenotypically defined remission were p53 negative. Relapsed T-, B- ALL and AML develop p53 alteration. We reported positive p53 expression in cells of patients with advanced stages of CLL in comparison to them with initial stage of disease at examination. As well as in the group of B- cell lymphomas only samples of patients with generalized FCC lymphoma at diagnosis were p53 positive. We detected p53 positive cells in immunologically defined myeloid blast crisis of CML opposite to p53 negativity in chronic phase of disease. The finding of p53 positive BM cells without immunophenotypic blast markers in two of followed cases documented the contributing value of p53 detection in their characterization. On the basis of above findings we conclude, that cytofluorometric determination of p53 expression may contribute to the better definition of leukemic phenotype. Loss of the normal p53 function may be important in the genesis of some leukemias

  19. Common and specific signatures of gene expression and protein-protein interactions in autoimmune diseases.

    PubMed

    Tuller, T; Atar, S; Ruppin, E; Gurevich, M; Achiron, A

    2013-03-01

    The aim of this study is to understand intracellular regulatory mechanisms in peripheral blood mononuclear cells (PBMCs), which are either common to many autoimmune diseases or specific to some of them. We incorporated large-scale data such as protein-protein interactions, gene expression and demographical information of hundreds of patients and healthy subjects, related to six autoimmune diseases with available large-scale gene expression measurements: multiple sclerosis (MS), systemic lupus erythematosus (SLE), juvenile rheumatoid arthritis (JRA), Crohn's disease (CD), ulcerative colitis (UC) and type 1 diabetes (T1D). These data were analyzed concurrently by statistical and systems biology approaches tailored for this purpose. We found that chemokines such as CXCL1-3, 5, 6 and the interleukin (IL) IL8 tend to be differentially expressed in PBMCs of patients with the analyzed autoimmune diseases. In addition, the anti-apoptotic gene BCL3, interferon-γ (IFNG), and the vitamin D receptor (VDR) gene physically interact with significantly many genes that tend to be differentially expressed in PBMCs of patients with the analyzed autoimmune diseases. In general, similar cellular processes tend to be differentially expressed in PBMC in the analyzed autoimmune diseases. Specifically, the cellular processes related to cell proliferation (for example, epidermal growth factor, platelet-derived growth factor, nuclear factor-κB, Wnt/β-catenin signaling, stress-activated protein kinase c-Jun NH2-terminal kinase), inflammatory response (for example, interleukins IL2 and IL6, the cytokine granulocyte-macrophage colony-stimulating factor and the B-cell receptor), general signaling cascades (for example, mitogen-activated protein kinase, extracellular signal-regulated kinase, p38 and TRK) and apoptosis are activated in most of the analyzed autoimmune diseases. However, our results suggest that in each of the analyzed diseases, apoptosis and chemotaxis are activated via

  20. Induction of apoptosis and bcl-2 expression in acute lymphoblastic leukaemia and non-Hodgkin's lymphoma in children.

    PubMed

    Pituch-Noworolska, A; Hajto, B; Balwierz, W; Klus, K

    2001-01-01

    bcl-2 expression is associated with the expression of the multidrug resistance molecule (p-gp) and the resistance of leukaemia cells to the induction of apoptosis. The activity of p-gp is the main mechanism of resistance of leukaemia cells to chemotherapy. This study assessed the induction of apoptosis of acute lymphoblastic leukaemia (ALL) and non-Hodgkin's lymphoma (NHL) blastic cells following in vitro treatment with dexamethasone (DXM), vincristine (VCR), and tumour necrosis factor (TNF) in relation to the expression of bcl-2 and p-gp. Common ALL (cALL; n = 24 patients), common ALL with co-expression of myeloid antigens (cALL + My; n = 9), ALL-T (n = 9), and NHL [n = 6 (T type, n = 2; B type, n = 4)] were included. The expression of bcl-2 and p-gp and apoptosis were assayed by flow cytometry. Spontaneous apoptosis was low (< 5%) in cALL and ALL-T and higher (> 8%) in NHL and cALL + My. A high frequency of bcl-2 expression was noted in cALL and cALL + My. A high frequency of p-gp expression was observed in cALL + My, ALL-T, and NHL. There was a reverse association between bcl-2 expression and spontaneous apoptosis. DXM-induced apoptosis was observed in 52.63%, TNF-induced in 42.85%, VCR-induced in 36.36%, and GM-CSF-induced in 33.3% of leukaemia and lymphoma cases. DXM and GM-CSF-driven apoptosis was reversibly associated with bcl-2-expression (bcl-2-dependent mechanism). VCR and TNF-driven apoptosis was not associated with bcl-2 expression, suggesting a different, bcl-2-independent, mechanism(s) of its induction. The in vitro induction of apoptosis was not associated with expression of p-gp. PMID:11855781

  1. Immunohistochemical evaluation of mx protein expression in canine encephalitides.

    PubMed

    Porter, B F; Ambrus, A; Storts, R W

    2006-11-01

    Mx proteins are a group of interferon-induced GTPases whose expression has been demonstrated in a number of human viral infections and in some idiopathic inflammatory diseases. In this study, the expression of Mx protein was evaluated in known viral, nonviral, and idiopathic encephalitides in the dog via immunohistochemistry using an antibody against human MxA. All 12 cases of confirmed viral encephalitis, including 7 cases of canine distemper, 4 cases of canine herpesvirus, and 1 case of rabies, were Mx positive. In canine distemper cases, staining was particularly strong and a variety of cell types were positive, including astrocytes, macrophages/microglia, and neurons. Immunoreactivity for Mx protein was evident in a few cases of nonviral infectious encephalitis, including neosporosis (1/1), Chagas disease (2/3), aspergillosis (1/2), and encephalitozoonosis (1/1). Consistent staining was observed in most cases of idiopathic encephalitis, including granulomatous meningoencephalomyelitis (7/7), necrotizing meningoencephalitis of pug dogs (6/7), and necrotizing encephalitis of the Yorkshire Terrier (3/3) and Maltese (1/1) breeds. Mx staining was negative in 5 normal dog brains; 3 cases of cryptococcosis; and single cases of blastomycosis, protothecosis, and bacterial meningitis. PMID:17099155

  2. Transient Expression of Proteins by Hydrodynamic Gene Delivery in Mice

    PubMed Central

    Kovacsics, Daniella; Raper, Jayne

    2014-01-01

    Efficient expression of transgenes in vivo is of critical importance in studying gene function and developing treatments for diseases. Over the past years, hydrodynamic gene delivery (HGD) has emerged as a simple, fast, safe and effective method for delivering transgenes into rodents. This technique relies on the force generated by the rapid injection of a large volume of physiological solution to increase the permeability of cell membranes of perfused organs and thus deliver DNA into cells. One of the main advantages of HGD is the ability to introduce transgenes into mammalian cells using naked plasmid DNA (pDNA). Introducing an exogenous gene using a plasmid is minimally laborious, highly efficient and, contrary to viral carriers, remarkably safe. HGD was initially used to deliver genes into mice, it is now used to deliver a wide range of substances, including oligonucleotides, artificial chromosomes, RNA, proteins and small molecules into mice, rats and, to a limited degree, other animals. This protocol describes HGD in mice and focuses on three key aspects of the method that are critical to performing the procedure successfully: correct insertion of the needle into the vein, the volume of injection and the speed of delivery. Examples are given to show the application of this method to the transient expression of two genes that encode secreted, primate-specific proteins, apolipoprotein L-I (APOL-I) and haptoglobin-related protein (HPR). PMID:24837006

  3. Transient expression of proteins by hydrodynamic gene delivery in mice.

    PubMed

    Kovacsics, Daniella; Raper, Jayne

    2014-01-01

    Efficient expression of transgenes in vivo is of critical importance in studying gene function and developing treatments for diseases. Over the past years, hydrodynamic gene delivery (HGD) has emerged as a simple, fast, safe and effective method for delivering transgenes into rodents. This technique relies on the force generated by the rapid injection of a large volume of physiological solution to increase the permeability of cell membranes of perfused organs and thus deliver DNA into cells. One of the main advantages of HGD is the ability to introduce transgenes into mammalian cells using naked plasmid DNA (pDNA). Introducing an exogenous gene using a plasmid is minimally laborious, highly efficient and, contrary to viral carriers, remarkably safe. HGD was initially used to deliver genes into mice, it is now used to deliver a wide range of substances, including oligonucleotides, artificial chromosomes, RNA, proteins and small molecules into mice, rats and, to a limited degree, other animals. This protocol describes HGD in mice and focuses on three key aspects of the method that are critical to performing the procedure successfully: correct insertion of the needle into the vein, the volume of injection and the speed of delivery. Examples are given to show the application of this method to the transient expression of two genes that encode secreted, primate-specific proteins, apolipoprotein L-I (APOL-I) and haptoglobin-related protein (HPR). PMID:24837006

  4. Heat shock protein 70-hom gene polymorphism and protein expression in multiple sclerosis.

    PubMed

    Boiocchi, C; Monti, M C; Osera, C; Mallucci, G; Pistono, C; Ferraro, O E; Nosari, G; Romani, A; Cuccia, M; Govoni, S; Pascale, A; Montomoli, C; Bergamaschi, R

    2016-09-15

    Immune-mediated and neurodegenerative mechanisms are involved in multiple sclerosis (MS). Growing evidences highlight the role of HSP70 genes in the susceptibility of some neurological diseases. In this explorative study we analyzed a polymorphism (i.e. HSP70-hom rs2227956) of the gene HSPA1L, which encodes for the protein hsp70-hom. We sequenced the polymorphism by polymerase chain reaction (PCR), in 191 MS patients and 365 healthy controls. The hsp70-hom protein expression was quantified by western blotting. We reported a strong association between rs2227956 polymorphism and MS risk, which is independent from the association with HSP70-2 rs1061581, and a significant link between hsp70-hom protein expression and MS severity. PMID:27609295

  5. Simvastatin enhances bone morphogenetic protein receptor type II expression

    SciTech Connect

    Hu Hong; Sung, Arthur; Zhao, Guohua; Shi, Lingfang; Qiu Daoming; Nishimura, Toshihiko; Kao, Peter N. . E-mail: peterkao@stanford.edu

    2006-01-06

    Statins confer therapeutic benefits in systemic and pulmonary vascular diseases. Bone morphogenetic protein (BMP) receptors serve essential signaling functions in cardiovascular development and skeletal morphogenesis. Mutations in BMP receptor type II (BMPR2) are associated with human familial and idiopathic pulmonary arterial hypertension, and pathologic neointimal proliferation of vascular endothelial and smooth muscle cells within small pulmonary arteries. In severe experimental pulmonary hypertension, simvastatin reversed disease and conferred a 100% survival advantage. Here, modulation of BMPR2 gene expression by simvastatin is characterized in human embryonic kidney (HEK) 293T, pulmonary artery smooth muscle, and lung microvascular endothelial cells (HLMVECs). A 1.4 kb BMPR2 promoter containing Egr-1 binding sites confers reporter gene activation in 293T cells which is partially inhibited by simvastatin. Simvastatin enhances steady-state BMPR2 mRNA and protein expression in HLMVEC, through posttranscriptional mRNA stabilization. Simvastatin induction of BMPR2 expression may improve BMP-BMPR2 signaling thereby enhancing endothelial differentiation and function.

  6. Protein tyrosine phosphatases expression during development of mouse superior colliculus.

    PubMed

    Reinhard, Jacqueline; Horvat-Bröcker, Andrea; Illes, Sebastian; Zaremba, Angelika; Knyazev, Piotr; Ullrich, Axel; Faissner, Andreas

    2009-12-01

    Protein tyrosine phosphatases (PTPs) are key regulators of different processes during development of the central nervous system. However, expression patterns and potential roles of PTPs in the developing superior colliculus remain poorly investigated. In this study, a degenerate primer-based reverse transcription-polymerase chain reaction (RT-PCR) approach was used to isolate seven different intracellular PTPs and nine different receptor-type PTPs (RPTPs) from embryonic E15 mouse superior colliculus. Subsequently, the expression patterns of 11 PTPs (TC-PTP, PTP1C, PTP1D, PTP-MEG2, PTP-PEST, RPTPJ, RPTPε, RPTPRR, RPTPσ, RPTPκ and RPTPγ) were further analyzed in detail in superior colliculus from embryonic E13 to postnatal P20 stages by quantitative real-time RT-PCR, Western blotting and immunohistochemistry. Each of the 11 PTPs exhibits distinct spatiotemporal regulation of mRNAs and proteins in the developing superior colliculus suggesting their versatile roles in genesis of neuronal and glial cells and retinocollicular topographic mapping. At E13, additional double-immunohistochemical analysis revealed the expression of PTPs in collicular nestin-positive neural progenitor cells and RC-2-immunoreactive radial glia cells, indicating the potential functional importance of PTPs in neurogenesis and gliogenesis. PMID:19727691

  7. Transformation of Escherichia coli and protein expression using lipoplex mimicry.

    PubMed

    Yun, Chul-Ho; Bae, Chun-Sik; Ahn, Taeho

    2016-11-01

    We investigated a "one-step" method for transformation of and protein expression in Escherichia coli (E. coli) using a complex of n-stearylamine, a cationic lipid, and plasmid DNA, which mimics lipoplex-based approaches. When E. coli cells were treated with the cationic lipid-plasmid complex, the transformation efficiencies were in the range of approximately 2-3 × 10(6) colony-forming units. Further increase in the efficiency was obtained by co-treatment with calcium chloride (or rubidium chloride) and the complexes. Moreover, after DNA transfer, E. coli cells successfully expressed plasmid-encoded proteins such as cytochrome P450s and glutathione-S-transferase without overnight incubation of the cells to form colonies, an indispensable step in other bacterial transformation methods. In this study, we provide a simple method for E. coli transformation, which does not require the preparation of competent cells. The present method also shortens the overall procedures for transformation and gene expression in E. coli by omitting the colony-forming step. PMID:27416742

  8. Structure and expression of a novel compact myelin protein – Small VCP-interacting protein (SVIP)

    SciTech Connect

    Wu, Jiawen; Peng, Dungeng; Voehler, Markus; Sanders, Charles R.; Li, Jun

    2013-10-11

    Highlights: •SVIP (small p97/VCP-interacting protein) co-localizes with myelin basic protein (MBP) in compact myelin. •We determined that SVIP is an intrinsically disordered protein (IDP). •The helical content of SVIP increases dramatically during its interaction with negatively charged lipid membrane. •This study provides structural insight into interactions between SVIP and myelin membranes. -- Abstract: SVIP (small p97/VCP-interacting protein) was initially identified as one of many cofactors regulating the valosin containing protein (VCP), an AAA+ ATPase involved in endoplasmic-reticulum-associated protein degradation (ERAD). Our previous study showed that SVIP is expressed exclusively in the nervous system. In the present study, SVIP and VCP were seen to be co-localized in neuronal cell bodies. Interestingly, we also observed that SVIP co-localizes with myelin basic protein (MBP) in compact myelin, where VCP was absent. Furthermore, using nuclear magnetic resonance (NMR) and circular dichroism (CD) spectroscopic measurements, we determined that SVIP is an intrinsically disordered protein (IDP). However, upon binding to the surface of membranes containing a net negative charge, the helical content of SVIP increases dramatically. These findings provide structural insight into interactions between SVIP and myelin membranes.

  9. Detecting Protein Complexes in Protein Interaction Networks Modeled as Gene Expression Biclusters

    PubMed Central

    Hanna, Eileen Marie; Zaki, Nazar; Amin, Amr

    2015-01-01

    Developing suitable methods for the detection of protein complexes in protein interaction networks continues to be an intriguing area of research. The importance of this objective originates from the fact that protein complexes are key players in most cellular processes. The more complexes we identify, the better we can understand normal as well as abnormal molecular events. Up till now, various computational methods were designed for this purpose. However, despite their notable performance, questions arise regarding potential ways to improve them, in addition to ameliorative guidelines to introduce novel approaches. A close interpretation leads to the assent that the way in which protein interaction networks are initially viewed should be adjusted. These networks are dynamic in reality and it is necessary to consider this fact to enhance the detection of protein complexes. In this paper, we present “DyCluster”, a framework to model the dynamic aspect of protein interaction networks by incorporating gene expression data, through biclustering techniques, prior to applying complex-detection algorithms. The experimental results show that DyCluster leads to higher numbers of correctly-detected complexes with better evaluation scores. The high accuracy achieved by DyCluster in detecting protein complexes is a valid argument in favor of the proposed method. DyCluster is also able to detect biologically meaningful protein groups. The code and datasets used in the study are downloadable from https://github.com/emhanna/DyCluster. PMID:26641660

  10. Detecting Protein Complexes in Protein Interaction Networks Modeled as Gene Expression Biclusters.

    PubMed

    Hanna, Eileen Marie; Zaki, Nazar; Amin, Amr

    2015-01-01

    Developing suitable methods for the detection of protein complexes in protein interaction networks continues to be an intriguing area of research. The importance of this objective originates from the fact that protein complexes are key players in most cellular processes. The more complexes we identify, the better we can understand normal as well as abnormal molecular events. Up till now, various computational methods were designed for this purpose. However, despite their notable performance, questions arise regarding potential ways to improve them, in addition to ameliorative guidelines to introduce novel approaches. A close interpretation leads to the assent that the way in which protein interaction networks are initially viewed should be adjusted. These networks are dynamic in reality and it is necessary to consider this fact to enhance the detection of protein complexes. In this paper, we present "DyCluster", a framework to model the dynamic aspect of protein interaction networks by incorporating gene expression data, through biclustering techniques, prior to applying complex-detection algorithms. The experimental results show that DyCluster leads to higher numbers of correctly-detected complexes with better evaluation scores. The high accuracy achieved by DyCluster in detecting protein complexes is a valid argument in favor of the proposed method. DyCluster is also able to detect biologically meaningful protein groups. The code and datasets used in the study are downloadable from https://github.com/emhanna/DyCluster. PMID:26641660

  11. Design of riboregulators for control of cyanobacterial (Synechocystis) protein expression.

    PubMed

    Abe, Koichi; Sakai, Yuta; Nakashima, Saki; Araki, Masataka; Yoshida, Wataru; Sode, Koji; Ikebukuro, Kazunori

    2014-02-01

    Cyanobacteria are attractive host bacteria for biofuel production because they can covert CO2 to biofuel lipids using only sunlight, water, and inorganic ions. For genetically engineering an ideal cyanobacterium, a synthetic biological approach is promising but few genetic components have been characterized in cyanobacteria. Here for controlling cyanobacterial protein expression, we constructed riboregulators, that one of the post-transcriptional regulators composed of RNAs. Riboregulators harboring a ribosome-binding site suitable for Synechocystis sp. were designed by trial and error using Escherichia coli as host bacteria. The designed riboregulators were effective in Synechocystis sp. as well as E. coli with slight interference on growth only observed in E. coli. They will therefore be useful tools for controlling target gene expression. PMID:24068508

  12. Evaluation of photodynamic therapy in adhesion protein expression

    PubMed Central

    PACHECO-SOARES, CRISTINA; MAFTOU-COSTA, MAIRA; DA CUNHA MENEZES COSTA, CAROLINA GENÚNCIO; DE SIQUEIRA SILVA, ANDREZA CRISTINA; MORAES, KAREN C.M.

    2014-01-01

    Photodynamic therapy (PDT) is a treatment modality that has clinical applications in both non-neoplastic and neoplastic diseases. PDT involves a light-sensitive compound (photosensitizer), light and molecular oxygen. This procedure may lead to several different cellular responses, including cell death. Alterations in the attachment of cancer cells to the substratum and to each other are important consequences of photodynamic treatment. PDT may lead to changes in the expression of cellular adhesion structure and cytoskeleton integrity, which are key factors in decreasing tumor metastatic potential. HEp-2 cells were photosensitized with aluminum phthalocyanine tetrasulfonate and zinc phthalocyanine, and the proteins β1-integrin and focal adhesion kinase (FAK) were assayed using fluorescence microscopy. The verification of expression changes in the genes for FAK and β1 integrin were performed by reverse transcription-polymerase chain reaction (RT-PCR). The results revealed that HEp-2 cells do not express β-integrin or FAK 12 h following PDT. It was concluded that the PDT reduces the adhesive ability of HEp-2 cells, inhibiting their metastatic potential. The present study aimed to analyze the changes in the expression and organization of cellular adhesion elements and the subsequent metastatic potential of HEp-2 cells following PDT treatment. PMID:25013490

  13. Extracellular matrix protein expression is brain region dependent.

    PubMed

    Dauth, Stephanie; Grevesse, Thomas; Pantazopoulos, Harry; Campbell, Patrick H; Maoz, Ben M; Berretta, Sabina; Parker, Kevin Kit

    2016-05-01

    In the brain, extracellular matrix (ECM) components form networks that contribute to structural and functional diversity. Maladaptive remodeling of ECM networks has been reported in neurodegenerative and psychiatric disorders, suggesting that the brain microenvironment is a dynamic structure. A lack of quantitative information about ECM distribution in the brain hinders an understanding of region-specific ECM functions and the role of ECM in health and disease. We hypothesized that each ECM protein as well as specific ECM structures, such as perineuronal nets (PNNs) and interstitial matrix, are differentially distributed throughout the brain, contributing to the unique structure and function in the various regions of the brain. To test our hypothesis, we quantitatively analyzed the distribution, colocalization, and protein expression of aggrecan, brevican, and tenascin-R throughout the rat brain utilizing immunohistochemistry and mass spectrometry analysis and assessed the effect of aggrecan, brevican, and/or tenascin-R on neurite outgrowth in vitro. We focused on aggrecan, brevican, and tenascin-R as they are especially expressed in the mature brain, and have established roles in brain development, plasticity, and neurite outgrowth. The results revealed a differentiated distribution of all three proteins throughout the brain and indicated that their presence significantly reduces neurite outgrowth in a 3D in vitro environment. These results underline the importance of a unique and complex ECM distribution for brain physiology and suggest that encoding the distribution of distinct ECM proteins throughout the brain will aid in understanding their function in physiology and in turn assist in identifying their role in disease. J. Comp. Neurol. 524:1309-1336, 2016. © 2016 Wiley Periodicals, Inc. PMID:26780384

  14. Trichohyalin-like 1 protein, a member of fused S100 proteins, is expressed in normal and pathologic human skin

    SciTech Connect

    Yamakoshi, Takako; Makino, Teruhiko; Ur Rehman, Mati; Yoshihisa, Yoko; Sugimori, Michiya; Shimizu, Tadamichi

    2013-03-01

    Highlights: ► Trichohyalin-like 1 protein is a member of the fused-type S100 protein gene family. ► Specific antibodies against the C-terminus of the TCHHL1 protein were generated. ► TCHHL1 proteins were expressed in the basal layer of the normal epidermis. ► TCHHL1 proteins were strongly expressed in tumor nests of BCC and SCC. ► The expression of TCHHL1 proteins increased in epidermis of psoriasis vulgaris. - Abstract: Trichohyalin-like 1 (TCHHL1) protein is a novel member of the fused-type S100 protein gene family. The deduced amino acid sequence of TCHHL1 contains an EF-hand domain in the N-terminus, one trans-membrane domain and a nuclear localization signal. We generated specific antibodies against the C-terminus of the TCHHL1 protein and examined the expression of TCHHL1 proteins in normal and pathological human skin. An immunohistochemical study showed that TCHHL1 proteins were expressed in the basal layer of the normal epidermis. In addition, signals of TCHHL1 proteins were observed around the nuclei of cultured growing keratinocytes. Accordingly, TCHHL1 mRNA has been detected in normal skin and cultured growing keratinocytes. Furthermore, TCHHL1 proteins were strongly expressed in the peripheral areas of tumor nests in basal cell carcinomas and squamous cell carcinomas. A dramatic increase in the number of Ki67 positive cells was observed in TCHHL1-expressing areas. The expression of TCHHL1 proteins also increased in non-cancerous hyperproliferative epidermal tissues such as those of psoriasis vulgaris and lichen planus. These findings highlight the possibility that TCHHL1 proteins are expressed in growing keratinocytes of the epidermis and might be associated with the proliferation of keratinocytes.

  15. Expression and purification of recombinant polyomavirus VP2 protein and its interactions with polyomavirus proteins

    NASA Technical Reports Server (NTRS)

    Cai, X.; Chang, D.; Rottinghaus, S.; Consigli, R. A.; Spooner, B. S. (Principal Investigator)

    1994-01-01

    Recombinant polyomavirus VP2 protein was expressed in Escherichia coli (RK1448), using the recombinant expression system pFPYV2. Recombinant VP2 was purified to near homogeneity by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, electroelution, and Extracti-Gel chromatography. Polyclonal serum to this protein which reacted specifically with recombinant VP2 as well as polyomavirus virion VP2 and VP3 on Western blots (immunoblots) was produced. Purified VP2 was used to establish an in vitro protein-protein interaction assay with polyomavirus structural proteins and purified recombinant VP1. Recombinant VP2 interacted with recombinant VP1, virion VP1, and the four virion histones. Recombinant VP1 coimmunoprecipitated with recombinant VP2 or truncated VP2 (delta C12VP2), which lacked the carboxy-terminal 12 amino acids. These experiments confirmed the interaction between VP1 and VP2 and revealed that the carboxyterminal 12 amino acids of VP2 and VP3 were not necessary for formation of this interaction. In vivo VP1-VP2 interaction study accomplished by cotransfection of COS-7 cells with VP2 and truncated VP1 (delta N11VP1) lacking the nuclear localization signal demonstrated that VP2 was capable of translocating delta N11VP1 into the nucleus. These studies suggest that complexes of VP1 and VP2 may be formed in the cytoplasm and cotransported to the nucleus for virion assembly to occur.

  16. Cell-Free Protein Expression under Macromolecular Crowding Conditions

    PubMed Central

    Ge, Xumeng; Luo, Dan; Xu, Jianfeng

    2011-01-01

    Background Cell-free protein expression (CFPE) comprised of in vitro transcription and translation is currently manipulated in relatively dilute solutions, in which the macromolecular crowding effects present in living cells are largely ignored. This may not only affect the efficiency of protein synthesis in vitro, but also limit our understanding of the functions and interactions of biomolecules involved in this fundamental biological process. Methodology/Principal Findings Using cell-free synthesis of Renilla luciferase in wheat germ extract as a model system, we investigated the CFPE under macromolecular crowding environments emulated with three different crowding agents: PEG-8000, Ficoll-70 and Ficoll-400, which vary in chemical properties and molecular size. We found that transcription was substantially enhanced in the macromolecular crowding solutions; up to 4-fold increase in the mRNA production was detected in the presence of 20% (w/v) of Ficoll-70. In contrast, translation was generally inhibited by the addition of each of the three crowding agents. This might be due to PEG-induced protein precipitation and non-specific binding of translation factors to Ficoll molecules. We further explored a two-stage CFPE in which transcription and translation was carried out under high then low macromolecular crowding conditions, respectively. It produced 2.2-fold higher protein yield than the coupled CFPE control. The macromolecular crowding effects on CFPE were subsequently confirmed by cell-free synthesis of an approximately two-fold larger protein, Firefly luciferase, under macromolecular crowding environments. Conclusions/Significance Three macromolecular crowding agents used in this research had opposite effects on transcription and translation. The results of this study should aid researchers in their choice of macromolecular crowding agents and shows that two-stage CFPE is more efficient than coupled CFPE. PMID:22174874

  17. Characterization of protein expression levels with label-free detected reverse phase protein arrays.

    PubMed

    Guo, Xuexue; Deng, Yihong; Zhu, Chenggang; Cai, Junlong; Zhu, Xiangdong; Landry, James P; Zheng, Fengyun; Cheng, Xunjia; Fei, Yiyan

    2016-09-15

    In reverse-phase protein arrays (RPPA), one immobilizes complex samples (e.g., cellular lysate, tissue lysate or serum etc.) on solid supports and performs parallel reactions of antibodies with immobilized protein targets from the complex samples. In this work, we describe a label-free detection of RPPA that enables quantification of RPPA data and thus facilitates comparison of studies performed on different samples and on different solid supports. We applied this detection platform to characterization of phosphoserine aminotransferase (PSAT) expression levels in Acanthamoeba lysates treated with artemether and the results were confirmed by Western blot studies. PMID:27372609

  18. Protein kinase C alpha expression in breast and ovarian cancer.

    PubMed

    Lahn, Michael; Köhler, Gabriele; Sundell, Karen; Su, Chen; Li, Shuyu; Paterson, Blake M; Bumol, Thomas F

    2004-01-01

    In recent years research has focused on the development of specific, targeted drugs to treat cancer. One approach has been to block intracellular signaling proteins, such as protein kinase C alpha (PKC-alpha). To help support the rationale for clinical studies of a PKC-alpha-targeted therapy in breast and ovarian cancers, we reviewed publications studying PKC-alpha expression in these tumors. Since these investigations were mostly performed in cell lines, we supplemented this review with some preliminary findings from studies examining PKC-alpha expression in tumor tissue biopsies obtained from patients with breast and ovarian cancer. Based on the reviewed publications using representative cell lines and our preliminary findings on tumor tissue of patients with breast cancer, we infer that PKC-alpha levels may especially be increased in breast cancer patients with low or negative estrogen receptor (ER) levels. Thus, clinical studies determining efficacy of selective or specific inhibitors of PKC-alpha should include determination of ER status in order to help answer whether blocking PKC-alpha in patients with low or absent ER can result in clinical benefit. PMID:15459489

  19. PPAR-β/δ activation promotes phospholipid transfer protein expression.

    PubMed

    Chehaibi, Khouloud; Cedó, Lídia; Metso, Jari; Palomer, Xavier; Santos, David; Quesada, Helena; Naceur Slimane, Mohamed; Wahli, Walter; Julve, Josep; Vázquez-Carrera, Manuel; Jauhiainen, Matti; Blanco-Vaca, Francisco; Escolà-Gil, Joan Carles

    2015-03-15

    The peroxisome proliferator-activated receptor (PPAR)-β/δ has emerged as a promising therapeutic target for treating dyslipidemia, including beneficial effects on HDL cholesterol (HDL-C). In the current study, we determined the effects of the PPAR-β/δ agonist GW0742 on HDL composition and the expression of liver HDL-related genes in mice and cultured human cells. The experiments were carried out in C57BL/6 wild-type, LDL receptor (LDLR)-deficient mice and PPAR-β/δ-deficient mice treated with GW0742 (10mg/kg/day) or a vehicle solution for 14 days. GW0742 upregulated liver phospholipid transfer protein (Pltp) gene expression and increased serum PLTP activity in mice. When given to wild-type mice, GW0742 significantly increased serum HDL-C and HDL phospholipids; GW0742 also raised serum potential to generate preβ-HDL formation. The GW0742-mediated effects on liver Pltp expression and serum enzyme activity were completely abolished in PPAR-β/δ-deficient mice. GW0742 also stimulated PLTP mRNA expression in mouse J774 macrophages, differentiated human THP-1 macrophages and human hepatoma Huh7. Collectively, our findings demonstrate a common transcriptional upregulation by GW0742-activated PPAR-β/δ of Pltp expression in cultured cells and in mouse liver resulting in enhanced serum PLTP activity. Our results also indicate that PPAR-β/δ activation may modulate PLTP-mediated preβ-HDL formation and macrophage cholesterol efflux. PMID:25662586

  20. Population proteomics: quantitative variation within and among populations in cardiac protein expression.

    PubMed

    Rees, Bernard B; Andacht, Tracy; Skripnikova, Elena; Crawford, Douglas L

    2011-03-01

    Population analysis of gene expression is typically achieved by quantifying levels of mRNA; however, gene expression is also a function of protein translation and turnover. Therefore, a complete understanding of population variation in gene expression requires quantitative knowledge of protein expression within and among natural populations. We used two-dimensional fluorescence difference gel electrophoresis (2D-DIGE) to quantitatively compare expression of heart ventricle proteins among 18 individuals in three populations of the teleost fish Fundulus. Among populations, expressions between orthologous proteins and mRNAs were generally positively correlated. Additionally, similar to the pattern of cardiac mRNA expression for the same populations, we found considerable variation in protein expression both within and among populations: Of 408 protein features in 2D gels, 34% are significantly different (P < 0.01) among individuals within a population, 9% differ between populations, and 12% have a pattern of expression that suggests they have evolved by natural selection. Although similar to mRNA expression, the frequency of significant differences among populations is larger for proteins. Similar to mRNA expressions, expressions of most proteins are correlated to the expressions of many other proteins. However, the correlations among proteins are more extensive than the correlation for similar RNAs. These correlations suggest a greater coordinate regulation of protein than mRNA expression. The larger frequency of significant differences among populations and the greater frequency of correlated expression among proteins versus among RNAs suggest that the molecular mechanisms affecting protein expression enhance the differences among populations, and these regulatory steps could be a source of variation for adaptation. PMID:21109588

  1. Ras protein expression as a marker for breast cancer

    PubMed Central

    CALAF, GLORIA M.; ABARCA-QUINONES, JORGE

    2016-01-01

    Breast cancer, the most common neoplasm in women of all ages, is the leading cause of cancer-related mortality in women worldwide. Markers to help to predict the risk of progression and ultimately provide non-surgical treatment options would be of great benefit. At present, there are no available molecular markers to predict the risk of carcinoma in situ progression to invasive cancer; therefore, all women diagnosed with this type of malignancy must undergo surgery. Breast cancer is a heterogeneous complex disease, and different patients respond differently to different treatments. In breast cancer, analysis using immunohistochemical markers remains an essential component of routine pathological examinations, and plays an import role in the management of the disease by providing diagnostic and prognostic strategies. The aim of the present study was to identify a marker that can be used as a prognostic tool for breast cancer. For this purpose, we firstly used an established breast cancer model. MCF-10F, a spontaneously immortalized breast epithelial cell line was transformed by exposure to estrogen and radiation. MCF-10F cells were exposed to low doses of high linear energy transfer (LET) α particles (150 keV/μm) of radiation, and subsequently cultured in the presence of 17β-estradiol. Three cell lines were used: i) MCF-10F cells as a control; ii) Alpha5 cells, a malignant and tumorigenic cell line; and iii) Tumor2 cells derived from Alpha5 cells injected into nude mice. Secondly, we also used normal, benign and malignant breast specimens obtained from biopsies. The results revealed that the MCF-10F cells were negative for c-Ha-Ras protein expression; however, the Alpha5 and Tumor2 cell lines were positive for c-Ha-Ras protein expression. The malignant breast samples were also strongly positive for c-Ha-Ras expression. The findings of our study indicate that c-Ha-Ras protein expression may be used as a marker to predict the progression of breast cancer; this

  2. A novel chalcone derivative which acts as a microtubule depolymerising agent and an inhibitor of P-gp and BCRP in in-vitro and in-vivo glioblastoma models

    PubMed Central

    2009-01-01

    Background Over the past decades, in spite of intensive search, no significant increase in the survival of patients with glioblastoma has been obtained. The role of the blood-brain barrier (BBB) and especially the activity of efflux pumps belonging to the ATP Binding Cassette (ABC) family may, in part, explain this defect. Methods The in-vitro activities of JAI-51 on cell proliferation were assessed by various experimental approaches in four human and a murine glioblastoma cell lines. Using drug exclusion assays and flow-cytometry, potential inhibitory effects of JAI-51 on P-gp and BCRP were evaluated in sensitive or resistant cell lines. JAI-51 activity on in-vitro microtubule polymerization was assessed by tubulin polymerization assay and direct binding measurements by analytical ultracentrifugation. Finally, a model of C57BL/6 mice bearing subcutaneous GL26 glioblastoma xenografts was used to assess the activity of the title compound in vivo. An HPLC method was designed to detect JAI-51 in the brain and other target organs of the treated animals, as well as in the tumours. Results In the four human and the murine glioblastoma cell lines tested, 10 μM JAI-51 inhibited proliferation and blocked cells in the M phase of the cell cycle, via its activity as a microtubule depolymerising agent. This ligand binds to tubulin with an association constant of 2 × 105 M-1, overlapping the colchicine binding site. JAI-51 also inhibited the activity of P-gp and BCRP, without being a substrate of these efflux pumps. These in vitro studies were reinforced by our in vivo investigations of C57BL/6 mice bearing GL26 glioblastoma xenografts, in which JAI-51 induced a delay in tumour onset and a tumour growth inhibition, following intraperitoneal administration of 96 mg/kg once a week. In accordance with these results, JAI-51 was detected by HPLC in the tumours of the treated animals. Moreover, JAI-51 was detected in the brain, showing that the molecule is also able to cross the BBB

  3. mRNA expression and protein localization of dentin matrix protein 1 during dental root formation.

    PubMed

    Toyosawa, S; Okabayashi, K; Komori, T; Ijuhin, N

    2004-01-01

    Dentin matrix protein 1 (DMP1) is an acidic phosphoprotein. DMP1 was initially detected in dentin and later in other mineralized tissues including cementum and bone, but the DMP1 expression pattern in tooth is still controversial. To determine the precise localization of DMP1 messenger RNA (mRNA) and the protein in the tooth, we performed in situ hybridization and immunohistochemical analyses using rat molars and incisors during various stages of root formation. During root dentin formation of molars, DMP1 mRNA was detected in root odontoblasts in parallel with mineralization of the dentin. However, the level of DMP1 mRNA expression in root odontoblasts decreased near the coronal part and was absent in coronal odontoblasts. DMP1 protein was localized along dentinal tubules and their branches in mineralized root dentin, and the distribution of DMP1 shifted from the end of dentinal tubules to the base of the tubules as dentin formation progressed. During the formation of the acellular cementum, DMP1 mRNA was detected in cementoblasts lining the acellular cementum where its protein was localized. During the formation of the cellular cementum, DMP1 mRNA was detected in cementocytes embedded in the cellular cementum but not in cementoblasts, and its protein was localized in the pericellular cementum of cementocytes including their processes. During dentin formation of incisors, DMP1 mRNA was detected in odontoblasts on the cementum-related dentin, where its protein was localized along dentinal tubules near the mineralization front. The localization of DMP1 mRNA and protein in dentin and cementum was related to their mineralization, suggesting that one of the functions of DMP1 may be involved in the mineralization of dentin and cementum during root formation. PMID:14751569

  4. Paeonol reverses paclitaxel resistance in human breast cancer cells by regulating the expression of transgelin 2.

    PubMed

    Cai, Jiangxia; Chen, Siying; Zhang, Weipeng; Hu, Sasa; Lu, Jun; Xing, Jianfeng; Dong, Yalin

    2014-06-15

    Paclitaxel (PTX) is a first-line antineoplastic drug that is commonly used in clinical chemotherapy for breast cancer treatment. However, the occurrence of drug resistance in chemotherapeutic treatment has greatly restricted its use. There is thus an urgent need to find ways of reversing paclitaxel chemotherapy resistance in breast cancer. Plant-derived agents have great potential in preventing the onset of the carcinogenic process and enhancing the efficacy of mainstream antitumor drugs. Paeonol, a main compound derived from the root bark of Paeonia suffruticosa, has various biological activities, and is reported to have reversal drug resistance effects. This study established a paclitaxel-resistant human breast cancer cell line (MCF-7/PTX) and applied the dual-luciferase reporter gene assay, MTT assay, flow cytometry, transfection assay, Western blotting and the quantitative real-time polymerase chain reaction (qRT-PCR) to investigate the reversing effects of paeonol and its underlying mechanisms. It was found that transgelin 2 may mediate the resistance of MCF-7/PTX cells to paclitaxel by up-regulating the expressions of the adenosine-triphosphate binding cassette transporter proteins, including P-glycoprotein (P-gp), multidrug resistance associated protein 1 (MRP1), and breast cancer resistance protein (BCRP). Furthermore, the ability of paeonol to reverse paclitaxel resistance in breast cancer was confirmed, with a superior 8.2-fold reversal index. In addition, this study found that paeonol down-regulated the transgelin 2-mediated paclitaxel resistance by reducing the expressions of P-gp, MRP1, and BCRP in MCF-7/PTX cells. These results not only provide insight into the potential application of paeonol to the reversal of paclitaxel resistance, thus facilitating the sensitivity of breast cancer chemotherapy, but also highlight a potential role of transgelin 2 in the development of paclitaxel resistance in breast cancer. PMID:24680370

  5. Real-time quantification of protein expression at the single-cell level via dynamic protein synthesis translocation reporters

    PubMed Central

    Aymoz, Delphine; Wosika, Victoria; Durandau, Eric; Pelet, Serge

    2016-01-01

    Protein expression is a dynamic process, which can be rapidly induced by extracellular signals. It is widely appreciated that single cells can display large variations in the level of gene induction. However, the variability in the dynamics of this process in individual cells is difficult to quantify using standard fluorescent protein (FP) expression assays, due to the slow maturation of their fluorophore. Here we have developed expression reporters that accurately measure both the levels and dynamics of protein synthesis in live single cells with a temporal resolution under a minute. Our system relies on the quantification of the translocation of a constitutively expressed FP into the nucleus. As a proof of concept, we used these reporters to measure the transient protein synthesis arising from two promoters responding to the yeast hyper osmolarity glycerol mitogen-activated protein kinase pathway (pSTL1 and pGPD1). They display distinct expression dynamics giving rise to strikingly different instantaneous expression noise. PMID:27098003

  6. Chronic intermittent mechanical stress increases MUC5AC protein expression.

    PubMed

    Park, Jin-Ah; Tschumperlin, Daniel J

    2009-10-01

    Increased abundance of mucin secretory cells is a characteristic feature of the epithelium in asthma and other chronic airway diseases. We showed previously that the mechanical stresses of airway constriction, both in the intact mouse lung and a cell culture model, activate the epidermal growth factor receptor (EGFR), a known modulator of mucin expression in airway epithelial cells. Here we tested whether chronic, intermittent, short-duration compressive stress (30 cm H(2)O) is sufficient to increase the abundance of MUC5AC-positive cells and intracellular mucin levels in human bronchial epithelial cells cultured at an air-liquid interface. Compressive stress applied for 1 hour per day for 14 days significantly increased the percentage of cells staining positively for MUC5AC protein (22.0 +/- 3.8%, mean +/- SD) relative to unstimulated controls (8.6 +/- 2.6%), and similarly changed intracellular MUC5AC protein levels measured by Western and slot blotting. The effect of compressive stress was gradual, with significant changes in MUC5AC-positive cell numbers evident by Day 7, but required as little as 10 minutes of compressive stress daily. Daily treatment of cells with an EGFR kinase inhibitor (AG1478, 1 muM) significantly but incompletely attenuated the response to compressive stress. Complete attenuation could be accomplished by simultaneous treatment with the combination of AG1478 and a transforming growth factor (TGF)-beta(2) (1 microg/ml)-neutralizing antibody, or with anti-TGF-beta(2) alone. Our findings demonstrate that short duration episodes of mechanical stress, representative of those occurring during bronchoconstriction, are sufficient to increase goblet cell number and MUC5AC protein expression in bronchial epithelial cells in vitro. We propose that the mechanical environment present in asthma may fundamentally bias the composition of airway epithelial lining in favor of mucin secretory cells. PMID:19168703

  7. Protein expression patterns of the yeast mating response.

    PubMed

    Yuan, Haiyu; Zhang, Rongfei; Shao, Bin; Wang, Xuan; Ouyang, Qi; Hao, Nan; Luo, Chunxiong

    2016-06-13

    Microfluidics, in combination with time-lapse microscopy, is a transformative technology that significantly enhances our ability to monitor and probe biological processes in living cells. However, high-throughput microfluidic devices mostly require sophisticated preparatory and setup work and are thus hard to adopt by non-experts. In this work, we designed an easy-to-use microfluidic chip, which enables tracking of 48 GFP-tagged yeast strains, with each strain under two different stimulus conditions, in a single experiment. We used this technology to investigate the dynamic pattern of protein expression during the yeast mating differentiation response. High doses of pheromone induce cell cycle arrest and the shmoo morphology, whereas low doses of pheromone lead to elongation and chemotrophic growth. By systematically analyzing the protein dynamics of 156 pheromone-regulated genes, we identified groups of genes that are preferentially induced in response to low-dose pheromone (elongation during growth) or high-dose pheromone (shmoo formation and cell cycle arrest). The protein dynamics of these genes may provide insights into the mechanisms underlying the differentiation switch induced by different doses of pheromone. PMID:27177258

  8. Wilms Tumor 1 protein is not expressed in oral lymphangiomas.

    PubMed

    Netto, Ana Carolina de Mesquita; de Oliveira, Mariana Batista; Bernardes, Vanessa Fátima; Gomes, Carolina Cavaliéri; Gomez, Ricardo Santiago

    2012-01-01

    Lymphangiomas are benign hamartomatous lesions of lymphatic vessels. Wilms Tumor 1 (WT1) is a transcription factor that is activated in some human neoplasias. WT1 protein expression is observed in endothelial cells during angiogenesis and is a useful marker to distinguish between vascular proliferations and vascular malformations. The purpose of the present study is to report a case series of oral lymphangiomas together with an immunohistochemical investigation of WT1. Seventeen cases of oral lymphangioma were retrieved and reviewed. Immunohistochemical analysis of WT1 protein was performed and pyogenic granuloma samples were used as positive controls. The male/female ratio was 1.125 and most of the lesions occurred in young subjects. While pyogenic granuloma showed positive staining for WT1, the endothelial cells lining the thin-walled dilated lymphatic vessels of lymphangiomas were negative for this protein. The findings strengthen the idea that oral lymphangioma is a vascular malformation characterized by lymphatic dilatation without significant endothelial proliferation. PMID:23338265

  9. Expression of Water Channel Proteins in Mesembryanthemum crystallinum1

    PubMed Central

    Kirch, Hans-Hubert; Vera-Estrella, Rosario; Golldack, Dortje; Quigley, Francoise; Michalowski, Christine B.; Barkla, Bronwyn J.; Bohnert, Hans J.

    2000-01-01

    We have characterized transcripts for nine major intrinsic proteins (MIPs), some of which function as water channels (aquaporins), from the ice plant Mesembryanthemum crystallinum. To determine the cellular distribution and expression of these MIPs, oligopeptide-based antibodies were generated against MIP-A, MIP-B, MIP-C, or MIP-F, which, according to sequence and functional characteristics, are located in the plasma membrane (PM) and tonoplast, respectively. MIPs were most abundant in cells involved in bulk water flow and solute flux. The tonoplast MIP-F was found in all cells, while signature cell types identified different PM-MIPs: MIP-A predominantly in phloem-associated cells, MIP-B in xylem parenchyma, and MIP-C in the epidermis and endodermis of immature roots. Membrane protein analysis confirmed MIP-F as tonoplast located. MIP-A and MIP-B were found in tonoplast fractions and also in fractions distinct from either the tonoplast or PM. MIP-C was most abundant but not exclusive to PM fractions, where it is expected based on its sequence signature. We suggest that within the cell, MIPs are mobile, which is similar to aquaporins cycling through animal endosomes. MIP cycling and the differential regulation of these proteins observed under conditions of salt stress may be fundamental for the control of tissue water flux. PMID:10806230

  10. Protein Expression Analysis of Melanocyte Differentiation Antigen TRP-2.

    PubMed

    Avogadri, Francesca; Gnjatic, Sacha; Tassello, Jodie; Frosina, Denise; Hanson, Nicole; Laudenbach, Megan; Ritter, Erika; Merghoub, Taha; Busam, Klaus J; Jungbluth, Achim A

    2016-03-01

    Melanocyte differentiation antigens, such as gp100, tyrosinase, and Melan-A and their corresponding antibodies HMB45, T311, and A103, are major diagnostic tools in surgical pathology. Little is known about tyrosinase-related protein 2 (TRP-2, or dopachrome tautomerase/DCT) another melanocyte differentiation antigen, which is an enzymatic component of melanogenesis. We identified a commercial reagent to TRP-2, monoclonal antibody (mAb) C-9 and undertook a comprehensive analysis to assess its specificity and usefulness for surgical pathology. Subsequently, we analyzed panels of normal tissues and tumors. We show that TRP-2 is regularly expressed in melanocytes of the normal skin. In cutaneous nevi, TRP-2 is present in junctional as well as in dermal nevocytes. In malignant tumors, C-9 reactivity is restricted to melanocytic and related lesions and present in 84% and 58% of primary and metastatic melanomas, respectively. Ten primary melanomas of the anorectal mucosa were all positive. Like the other melanocyte differentiation antigens, TRP-2 was absent in 6 desmoplastic melanomas. Also, only 2 of 9 angiomyolipomas were TRP-2 positive. We conclude that mAb C-9 is a valuable reagent for the analysis of TRP-2 expression in archival surgical pathology material. The expression pattern of TRP-2 in melanocytic and related lesions appears to parallel other melanocyte differentiation antigens, although the overall incidence is lower than other antigens, such as Melan-A or gp100. PMID:26894771

  11. Improved protein quality in transgenic soybean expressing a de novo synthetic protein, MB-16.

    PubMed

    Zhang, Yunfang; Schernthaner, Johann; Labbé, Natalie; Hefford, Mary A; Zhao, Jiping; Simmonds, Daina H

    2014-06-01

    To improve soybean [Glycine max (L.) Merrill] seed nutritional quality, a synthetic gene, MB-16 was introduced into the soybean genome to boost seed methionine content. MB-16, an 11 kDa de novo protein enriched in the essential amino acids (EAAs) methionine, threonine, lysine and leucine, was originally developed for expression in rumen bacteria. For efficient seed expression, constructs were designed using the soybean codon bias, with and without the KDEL ER retention sequence, and β-conglycinin or cruciferin seed specific protein storage promoters. Homozygous lines, with single locus integrations, were identified for several transgenic events. Transgene transmission and MB-16 protein expression were confirmed to the T5 and T7 generations, respectively. Quantitative RT-PCR analysis of developing seed showed that the transcript peaked in growing seed, 5-6 mm long, remained at this peak level to the full-sized green seed and then was significantly reduced in maturing yellow seed. Transformed events carrying constructs with the rumen bacteria codon preference showed the same transcription pattern as those with the soybean codon preference, but the transcript levels were lower at each developmental stage. MB-16 protein levels, as determined by immunoblots, were highest in full-sized green seed but the protein virtually disappeared in mature seed. However, amino acid analysis of mature seed, in the best transgenic line, showed a significant increase of 16.2 and 65.9 % in methionine and cysteine, respectively, as compared to the parent. This indicates that MB-16 elevated the sulfur amino acids, improved the EAA seed profile and confirms that a de novo synthetic gene can enhance the nutritional quality of soybean. PMID:24435987

  12. β-asarone and levodopa co-administration increase striatal dopamine level in 6-hydroxydopamine induced rats by modulating P-glycoprotein and tight junction proteins at the blood-brain barrier and promoting levodopa into the brain.

    PubMed

    Huang, Liping; Deng, Minzhen; He, Yuping; Lu, Shiyao; Ma, Ruanxin; Fang, Yongqi

    2016-06-01

    Levodopa (L-dopa) is widely considered as one of the most effective drug constituents in the treatment of Parkinson's disease (PD), but the blood-brain barrier (BBB) permeability of L-dopa is <5%, which causes low efficacy. Neuroprotective effects of β-asarone on 6-hydroxydopamine (6-OHDA)-induced PD rats were demonstrated by our previous studies. Co-administration of β-asarone and L-dopa has not been explored until being investigated on PD rats in this study. PD rats were divided into four groups: untreated, L-dopa-treated, β-asarone-treated and co-administered-treated groups. All of the treatments were administered to the rats twice per day for 30 days. The L-dopa, dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), S100β and neuron-specific enolase (NSE) levels were subsequently determined. The P-glycoprotein (P-gp), zonula occludens-1 (ZO-1), claudin-5, occludin and actin expression was also assessed in cortex. Changes in BBB ultrastructure were observed using transmission electron microscopy. Our results showed that the co-administered treatment increased levels of L-dopa, DA, DOPAC and HVA in striatum, and S100β in plasma, but down-regulated NSE, P-gp, ZO-1, occludin, actin and claudin-5 in cortex. Crevices were observed between capillary endothelial cells at intercellular tight junction of the striatum in co-administered-treated group, while the endothelial cells in untreated group were tightly jointing each other. In addition, the correlations of L-dopa or DA and P-gp or tight junction proteins respectively were significantly negative in co-administered- and β-asarone-treated groups. These findings suggest that co-administered treatment may enhance the L-dopa BBB permeability and attenuate brain injury, which may be beneficial to PD treatment. PMID:26991136

  13. Comprehensive bioinformatics analysis of cell-free protein synthesis: identification of multiple protein properties that correlate with successful expression.

    PubMed

    Kurotani, Atsushi; Takagi, Tetsuo; Toyama, Mitsutoshi; Shirouzu, Mikako; Yokoyama, Shigeyuki; Fukami, Yasuo; Tokmakov, Alexander A

    2010-04-01

    High-throughput cell-free protein synthesis is being used increasingly in structural/functional genomics projects. However, the factors determining expression success are poorly understood. Here, we evaluated the expression of 3066 human proteins and their domains in a bacterial cell-free system and analyzed the correlation of protein expression with 39 physicochemical and structural properties of proteins. As a result of the bioinformatics analysis performed, we determined the 18 most influential features that affect protein amenability to cell-free expression. They include protein length; hydrophobicity; pI; content of charged, nonpolar, and aromatic residues;, cysteine content; solvent accessibility; presence of coiled coil; content of intrinsically disordered and structured (alpha-helix and beta-sheet) sequence; number of disulfide bonds and functional domains; presence of transmembrane regions; PEST motifs; and signaling sequences. This study represents the first comprehensive bioinformatics analysis of heterologous protein synthesis in a cell-free system. The rules and correlations revealed here provide a plethora of important insights into rationalization of cell-free protein production and can be of practical use for protein engineering with the aim of increasing expression success.-Kurotani, A., Takagi, T., Toyama, M., Shirouzu, M., Yokoyama, S., Fukami, Y., Tokmakov, A. A. Comprehensive bioinformatics analysis of cell-free protein synthesis: identification of multiple protein properties that correlate with successful expression. PMID:19940260

  14. Segmental expression and C-terminal labeling of protein ERp44 through protein trans-splicing.

    PubMed

    Dai, Xudong; Liu, Xiang-Qin; Meng, Qing

    2015-08-01

    Endoplasmic reticulum resident protein 44 (ERp44) is a member of the protein disulfide isomerase family and functions in oxidative protein folding in the endoplasmic reticulum. A structurally flexible C-terminal tail (C-tail) of ERp44 plays critical roles in dynamically regulating ERp44's function in protein folding quality control. The structure-function dynamics of ERp44's C-tail may be studied further using fluorescence and other techniques, if methods are found to label the C-tail site-specifically with a fluorescent group or segmentally with other desired labels. Here we have developed such methods, employing split inteins capable of protein trans-splicing, and identifying atypical S1 split inteins able to function efficiently at a suitable split site in the ERp44 sequence. One method demonstrated segmental expression of ERp44 for segmental labeling of the C-tail, another method efficiently added a commercially available fluorescent group to the C-terminus of ERp44, and both methods may also be generally useful for studying other proteins. PMID:25907381

  15. Expression-Enhanced Fluorescent Proteins Based on Enhanced Green Fluorescent Protein for Super-resolution Microscopy.

    PubMed

    Duwé, Sam; De Zitter, Elke; Gielen, Vincent; Moeyaert, Benjamien; Vandenberg, Wim; Grotjohann, Tim; Clays, Koen; Jakobs, Stefan; Van Meervelt, Luc; Dedecker, Peter

    2015-10-27

    "Smart fluorophores", such as reversibly switchable fluorescent proteins, are crucial for advanced fluorescence imaging. However, only a limited number of such labels is available, and many display reduced biological performance compared to more classical variants. We present the development of robustly photoswitchable variants of enhanced green fluorescent protein (EGFP), named rsGreens, that display up to 30-fold higher fluorescence in E. coli colonies grown at 37 °C and more than 4-fold higher fluorescence when expressed in HEK293T cells compared to their ancestor protein rsEGFP. This enhancement is not due to an intrinsic increase in the fluorescence brightness of the probes, but rather due to enhanced expression levels that allow many more probe molecules to be functional at any given time. We developed rsGreens displaying a range of photoswitching kinetics and show how these can be used for multimodal diffraction-unlimited fluorescence imaging such as pcSOFI and RESOLFT, achieving a spatial resolution of ∼70 nm. By determining the first ever crystal structures of a negative reversibly switchable FP derived from Aequorea victoria in both the "on"- and "off"-conformation we were able to confirm the presence of a cis-trans isomerization and provide further insights into the mechanisms underlying the photochromism. Our work demonstrates that genetically encoded "smart fluorophores" can be readily optimized for biological performance and provides a practical strategy for developing maturation- and stability-enhanced photochromic fluorescent proteins. PMID:26308583

  16. Recombinant protein production data after expression in the bacterium Escherichia coli.

    PubMed

    Cantu-Bustos, J Enrique; Cano Del Villar, Kevin D; Vargas-Cortez, Teresa; Morones-Ramirez, Jose Ruben; Balderas-Renteria, Isaias; Zarate, Xristo

    2016-06-01

    Fusion proteins have become essential for the expression and purification of recombinant proteins in Escherichia coli. The metal-binding protein CusF has shown several features that make it an attractive fusion protein and affinity tag: "Expression and purification of recombinant proteins in Escherichia coli tagged with the metal-binding protein CusF" (Cantu-Bustos et al., 2016 [1]). Here we present accompanying data from protein expression experiments; we tested different protein tags, temperatures, expression times, cellular compartments, and concentrations of inducer in order to obtain soluble protein and low formation of inclusion bodies. Additionally, we present data from the purification of the green fluorescent protein (GFP) tagged with CusF, using Ag(I) metal affinity chromatography. PMID:27014739

  17. Recombinant protein production data after expression in the bacterium Escherichia coli

    PubMed Central

    Cantu-Bustos, J. Enrique; Cano del Villar, Kevin D.; Vargas-Cortez, Teresa; Morones-Ramirez, Jose Ruben; Balderas-Renteria, Isaias; Zarate, Xristo

    2016-01-01

    Fusion proteins have become essential for the expression and purification of recombinant proteins in Escherichia coli. The metal-binding protein CusF has shown several features that make it an attractive fusion protein and affinity tag: "Expression and purification of recombinant proteins in Escherichia coli tagged with the metal-binding protein CusF" (Cantu-Bustos et al., 2016 [1]). Here we present accompanying data from protein expression experiments; we tested different protein tags, temperatures, expression times, cellular compartments, and concentrations of inducer in order to obtain soluble protein and low formation of inclusion bodies. Additionally, we present data from the purification of the green fluorescent protein (GFP) tagged with CusF, using Ag(I) metal affinity chromatography. PMID:27014739

  18. Effect of various protein kinase inhibitors on the induction of milk protein gene expression by prolactin.

    PubMed

    Bayat-Sarmadi, M; Houdebine, L M

    1993-03-01

    Prolactin has many known functions and one of them is to induce the expression of milk protein gene expression in the mammary gland. Specific membrane receptors have been recently characterized but the transduction mechanism involved in the transfer of the prolactin signal to milk protein genes remains unknown. In the present work, it is shown that several protein kinase inhibitors block prolactin action on milk protein genes. Primary rabbit mammary cells were cultured for several days on floating collagen gel in a serum-free medium. Prolactin and the inhibitors of protein kinase were then added to the culture medium. After 1 day, the concentration of alpha s1-casein in the culture medium was measured using a specific radioimmunoassay. The concentration of several mRNAs in cell extracts was also evaluated using Northern blot analysis. alpha s1-Casein secretion and alpha s1-casein mRNA accumulation were induced by prolactin. This induction was blocked by staurosporine, sphingosine, quercetin, genistein and to some extent by o-hydroxyphenyl acetate, but not by H7, polymyxin B, benzylsuccinate and lavendustin A. The concentration of the mRNA coding for transferrin, which is abundantly secreted in rabbit milk independently of prolactin action, was only moderately altered by the inhibitors. The concentration of two house-keeping mRNAs, beta-actin and glyceraldehyde 3-phosphate dehydrogenase, was lowered only by genistein after 1 day but not after 4 h of culture. These data show for the first time that a Ser/Thre kinase, which is not kinase C, and possibly a tyrosine kinase is involved in the transduction of the prolactin message from the receptor to the milk protein genes. PMID:8472863

  19. Phytomonas: A non-pathogenic trypanosomatid model for functional expression of proteins.

    PubMed

    Miranda, Mariana R; Sayé, Melisa; Reigada, Chantal; Carrillo, Carolina; Pereira, Claudio A

    2015-10-01

    Phytomonas are protozoan parasites from the Trypanosomatidae family which infect a wide variety of plants. Herein, Phytomonas Jma was tested as a model for functional expression of heterologous proteins. Green fluorescent protein expression was evaluated in Phytomonas and compared with Trypanosoma cruzi, the etiological agent of Chagas' disease. Phytomonas was able to express GFP at levels similar to T. cruzi although the transgenic selection time was higher. It was possible to establish an efficient transfection and selection protocol for protein expression. These results demonstrate that Phytomonas can be a good model for functional expression of proteins from other trypanosomatids, presenting the advantage of being completely safe for humans. PMID:26142019

  20. Lytic Promoters Express Protein during Herpes Simplex Virus Latency

    PubMed Central

    Russell, Tiffany A.; Tscharke, David C.

    2016-01-01

    Herpes simplex virus (HSV) has provided the prototype for viral latency with previously well-defined acute or lytic and latent phases. More recently, the deep quiescence of HSV latency has been questioned with evidence that lytic genes can be transcribed in this state. However, to date the only evidence that these transcripts might be translated has come from immunological studies that show activated T cells persist in the nervous system during latency. Here we use a highly sensitive Cre-marking model to show that lytic and latent phases are less clearly defined in two significant ways. First, around half of the HSV spread leading to latently infected sites occurred beyond the initial acute infection and second, we show direct evidence that lytic promoters can drive protein expression during latency. PMID:27348812

  1. Mycobacterium tuberculosis Rv1096 protein: gene cloning, protein expression, and peptidoglycan deacetylase activity

    PubMed Central

    2014-01-01

    Background Many bacteria modulate and evade the immune defenses of their hosts through peptidoglycan (PG) deacetylation. The PG deacetylases from Streptococcus pneumonia, Listeria monocytogenes and Lactococcus lactis have been characterized. However, thus far, the PG deacetylase of Mycobacterium tuberculosis has not been identified. Results In this study, we cloned the Rv1096 gene from the M. tuberculosis H37Rv strain and expressed Rv1096 protein in both Escherichia coli and M. smegmatis. The results showed that the purified Rv1096 protein possessed metallo-dependent PG deacetylase activity, which increased in the presence of Co2+. The kinetic parameters of the PG deacetylase towards M. smegmatis PG as a substrate were as follows: Km, 0.910 ± 0.007 mM; Vmax, 0.514 ± 0.038 μMmin-1; and Kcat = 0.099 ± 0.007 (S-1). Additionally, the viability of M. smegmatis in the presence of over-expressed Rv1096 protein was 109-fold higher than that of wild-type M. smegmatis after lysozyme treatment. Additionally, light microscopy and scanning electron microscopy showed that in the presence of over-expressed Rv1096 protein, M. smegmatis kept its regular shape, with an undamaged cell wall and smooth surface. These results indicate that Rv1096 caused deacetylation of cell wall PG, leading to lysozyme resistance in M. smegmatis. Conclusion We have determined that M. tuberculosis Rv1096 is a PG deacetylase. The PG deacetylase activity of Rv1096 contributed to lysozyme resistance in M. smegmatis. Our findings suggest that deacetylation of cell wall PG may be involved in evasion of host immune defenses by M. tuberculosis. PMID:24975018

  2. Protein expression and secretion in the yeast Yarrowia lipolytica.

    PubMed

    Nicaud, Jean-Marc; Madzak, Catherine; van den Broek, Peter; Gysler, Christof; Duboc, Philippe; Niederberger, Peter; Gaillardin, Claude

    2002-08-01

    Strains and vectors for protein expression and secretion have been developed in the yeast Yarrowia lipolytica. Host strains were constructed with non-reverting auxotrophic markers, deletions of protease-encoding genes, and carrying a docking platform. To drive transcription, either the synthetic hp4d or the inducible POX2 promoter were used. Protein secretion is either directed by the targeting sequence of the alkaline extracellular protease or the extracellular lipase (LIP2p) signal sequence. We describe a set of vectors based on these promoters, targeting sequences and two URA3 alleles as selection markers. The wild-type URA3 allele, ura3d1, was used for single-copy integration and a mutant URA3 allele, ura3d4, was used to select for multi-copy integration into the genome. These vectors were used to express the Y. lipolytica extracellular lipase LIP2p and the Aspergillus oryzae leucine amino peptidase II. Lipase production under the control of the hp4d promoter by a strain containing a single copy reached 1000 U ml(-1) in shake flasks, while a strain containing multiple integrations reached 2000 U ml(-1) in shake flasks, 11500 U ml(-1) in batch and 90500 U ml(-1) in fed batch. Leucine amino peptidase production under the control of the hp4d promoter reached 320 mU ml(-1) in batch with a mono-copy lapA integrant and 28000 mU ml(-1) in fed batch with a multi-copy transformant. PMID:12702287

  3. Neurotoxocarosis alters myelin protein gene transcription and expression.

    PubMed

    Heuer, Lea; Beyerbach, Martin; Lühder, Fred; Beineke, Andreas; Strube, Christina

    2015-06-01

    Neurotoxocarosis is an infection of the central nervous system caused by migrating larvae of the common dog and cat roundworms (Toxocara canis and Toxocara cati), which are zoonotic agents. As these parasites are prevalent worldwide and neuropathological and molecular investigations on neurotoxocarosis are scare, this study aims to characterise nerve fibre demyelination associated with neurotoxocarosis on a molecular level. Transcription of eight myelin-associated genes (Cnp, Mag, Mbp, Mog, Mrf-1, Nogo-A, Plp1, Olig2) was determined in the mouse model during six time points of the chronic phase of infection using qRT-PCR. Expression of selected proteins was analysed by Western blotting or immunohistochemistry. Additionally, demyelination and neuronal damage were investigated histologically. Significant differences (p ≤ 0.05) between transcription rates of T. canis-infected and uninfected control mice were detected for all analysed genes while T. cati affected five of eight investigated genes. Interestingly, 2', 3 ´-cyclic nucleotide 3'-phosphodiesterase (Cnp) and myelin oligodendrocyte glycoprotein (Mog) were upregulated in both T. canis- and T. cati-infected mice preceding demyelination. Later, CNPase expression was additionally enhanced. As expected, myelin basic protein (Mbp) was downregulated in cerebra and cerebella of T. canis-infected mice when severe demyelination was present 120 days post infectionem (dpi). The transcriptional pattern observed in the present study appears to reflect direct traumatic and hypoxic effects of larval migration as well as secondary processes including host immune reactions, demyelination and attempts to remyelinate damaged areas. PMID:25773181

  4. Fast plasmid based protein expression analysis in insect cells using an automated SplitGFP screen.

    PubMed

    Bleckmann, Maren; Schmelz, Stefan; Schinkowski, Christian; Scrima, Andrea; van den Heuvel, Joop

    2016-09-01

    Recombinant protein expression often presents a bottleneck for the production of proteins for use in many areas of animal-cell biotechnology. Difficult-to-express proteins require the generation of numerous expression constructs, where popular prokaryotic screening systems often fail to identify expression of multi domain or full-length protein constructs. Post-translational modified mammalian proteins require an alternative host system such as insect cells using the Baculovirus Expression Vector System (BEVS). Unfortunately this is time-, labor-, and cost-intensive. It is clearly desirable to find an automated and miniaturized fast multi-sample screening method for protein expression in such systems. With this in mind, in this paper a high-throughput initial expression screening method is described using an automated Microcultivation system in conjunction with fast plasmid based transient transfection in insect cells for the efficient generation of protein constructs. The applicability of the system is demonstrated for the difficult to express Nucleotide-binding Oligomerization Domain-containing protein 2 (NOD2). To enable detection of proper protein expression the rather weak plasmid based expression has been improved by a sensitive inline detection system. Here we present the functionality and application of the sensitive SplitGFP (split green fluorescent protein) detection system in insect cells. The successful expression of constructs is monitored by direct measurement of the fluorescence in the BioLector Microcultivation system. Additionally, we show that the results obtained with our plasmid-based SplitGFP protein expression screen correlate directly to the level of soluble protein produced in BEVS. In conclusion our automated SplitGFP screen outlines a sensitive, fast and reliable method reducing the time and costs required for identifying the optimal expression construct prior to large scale protein production in baculovirus infected insect cells

  5. Human odontoblasts express transient receptor protein and acid-sensing ion channel mechanosensor proteins.

    PubMed

    Solé-Magdalena, Antonio; Revuelta, Enrique G; Menénez-Díaz, Ivan; Calavia, Marta G; Cobo, Teresa; García-Suárez, Olivia; Pérez-Piñera, Pablo; De Carlos, Felix; Cobo, Juan; Vega, Jose A

    2011-05-01

    Diverse proteins of the denegerin/epithelial sodium channel (DEG/ENa(+) C) superfamily, in particular those belonging to the acid-sensing ion channel (ASIC) family, as well as some members of the transient receptor protein (TRP) channel, function as mechanosensors or may be required for mechanosensation in a diverse range of species and cell types. Therefore, we investigated the putative mechanosensitive function of human odontoblasts using immunohistochemistry to detect ENa(+) C subunits (α, β, and γ) and ASIC (1, 2, 3, and 4) proteins, as well as TRPV4, in these cells. Positive and specific immunoreactivity in the odontoblast soma and/or processes was detected for all proteins studied except α-ENa(+) C. The intensity of immunostaining was high for β-ENa(+) C and ASIC2, whereas it was low for ASIC1, ASIC3, γ-ENa(+) C, and TRPV4, being absent for α-ENa(+) C and ASIC4. These results suggest that human odontoblasts in situ express proteins related to mechanosensitive channels that probably participate in the mechanisms involved in teeth sensory transmission. PMID:20836083

  6. Cognitive and emotional information processing: protein synthesis and gene expression

    PubMed Central

    Sajikumar, Sreedharan; Navakkode, Sheeja; Korz, Volker; Frey, Julietta U

    2007-01-01

    Recent findings suggest that functional plasticity phenomena such as long-term potentiation (LTP) and long-term depression (LTD) – cellular processes underlying memory – are restricted to functional dendritic compartments. It was also shown, however, that a relatively strong activation of a synaptic input can abolish compartment restrictions. Our data support these findings and we present one cellular pathway responsible for uncompartmentalization of the normally localized plasticity processes by the action of rolipram, an inhibitor of type 4 phosphodiesterases. In contrast with compartment-restricted information processing, uncompartmentalization requires transcription. In the search for system relevance of compartmentalization versus uncompartmentalization we describe firstly data which show that more cognitive information processing in rats' behaviour may follow rules of compartmentalization, whereas stressful, more life-threatening, inputs abolish compartment-restricted information processing involving transcription. Our findings allow us to suggest that consolidation of processes which take place during the cognitive event most probably depend on local protein synthesis, whereas stress immediately induces gene expression in addition, resulting in a compartment-unspecific up-regulation of plasticity-related proteins (PRPs), providing the entire neuron with a higher level of ‘reactiveness’. These data would provide a specific functional cellular mechanism to respond differentially and effectively to behaviourally weighted inputs. PMID:17702813

  7. Human Articular Chondrocytes Express Multiple Gap Junction Proteins

    PubMed Central

    Mayan, Maria D.; Carpintero-Fernandez, Paula; Gago-Fuentes, Raquel; Martinez-de-Ilarduya, Oskar; Wang, Hong-Zhang; Valiunas, Virginijus; Brink, Peter; Blanco, Francisco J.

    2014-01-01

    Osteoarthritis (OA) is the most common joint disease and involves progressive degeneration of articular cartilage. The aim of this study was to investigate if chondrocytes from human articular cartilage express gap junction proteins called connexins (Cxs). We show that human chondrocytes in tissue express Cx43, Cx45, Cx32, and Cx46. We also find that primary chondrocytes from adults retain the capacity to form functional voltage-dependent gap junctions. Immunohistochemistry experiments in cartilage from OA patients revealed significantly elevated levels of Cx43 and Cx45 in the superficial zone and down through the next approximately 1000 μm of tissue. These zones corresponded with regions damaged in OA that also had high levels of proliferative cell nuclear antigen. An increased number of Cxs may help explain the increased proliferation of cells in clusters that finally lead to tissue homeostasis loss. Conversely, high levels of Cxs in OA cartilage reflect the increased number of adjacent cells in clusters that are able to interact directly by gap junctions as compared with hemichannels on single cells in normal cartilage. Our data provide strong evidence that OA patients have a loss of the usual ordered distribution of Cxs in the damaged zones and that the reductions in Cx43 levels are accompanied by the loss of correct Cx localization in the nondamaged areas. PMID:23416160

  8. Patagonfibrase modifies protein expression of tissue factor and protein disulfide isomerase in rat skin.

    PubMed

    Peichoto, María Elisa; Santoro, Marcelo Larami

    2016-09-01

    Patagonfibrase is a hemorrhagic metalloproteinase isolated from the venom of the South American rear-fanged snake Philodryas patagoniensis, and is an important contributor to local lesions inflicted by this species. The tissue factor (TF)-factor VIIa complex, besides triggering the coagulation cascade, has been demonstrated to be involved in inflammatory events. Our aim was to determine whether patagonfibrase affects the expression of TF and protein disulfide isomerase (PDI), an enzyme that controls TF biological activity, at the site of patagonfibrase injection, and thus if they may play a role in hemostatic and inflammatory events induced by snake venoms. Patagonfibrase (60 μg/kg) was administered s.c. to rats, and after 3 h blood was collected to evaluate hemostasis parameters, and skin fragments close to the site of injection were taken to assess TF and PDI expression. Patagonfibrase did not alter blood cell counts, plasma fibrinogen levels, or levels of TF activity in plasma. However, by semiquantitative Western blotting, patagonfibrase increased TF expression by 2-fold, and decreased PDI expression by 3-fold in skin samples. In agreement, by immunohistochemical analyses, prominent TF expression was observed in the subcutaneous tissue. Thus, patagonfibrase affects the local expression of TF and PDI without inducing any systemic hemostatic disturbance, although that they may be involved in the local inflammatory events induced by hemorrhagic metalloproteinases. Once antivenom therapy is not totally effective to treat the local injury induced by snake venoms, modulation of the activity and expression of TF and/or PDI might become a strategy for treating snake envenomation. PMID:27390042

  9. Neuroendocrine secretory protein 7B2: structure, expression and functions.

    PubMed Central

    Mbikay, M; Seidah, N G; Chrétien, M

    2001-01-01

    7B2 is an acidic protein residing in the secretory granules of neuroendocrine cells. Its sequence has been elucidated in many phyla and species. It shows high similarity among mammals. A Pro-Pro-Asn-Pro-Cys-Pro polyproline motif is its most conserved feature, being carried by both vertebrate and invertebrate sequences. It is biosynthesized as a precursor protein that is cleaved into an N-terminal fragment and a C-terminal peptide. In neuroendocrine cells, 7B2 functions as a specific chaperone for the proprotein convertase (PC) 2. Through the sequence around its Pro-Pro-Asn-Pro-Cys-Pro motif, it binds to an inactive proPC2 and facilitates its transport from the endoplasmic reticulum to later compartments of the secretory pathway where the zymogen is proteolytically matured and activated. Its C-terminal peptide can inhibit PC2 in vitro and may contribute to keep the enzyme transiently inactive in vivo. The PC2-7B2 model defines a new neuroendocrine paradigm whereby proteolytic activation of prohormones and proneuropeptides in the secretory pathway is spatially and temporally regulated by the dynamics of interactions between converting enzymes and their binding proteins. Interestingly, unlike PC2-null mice, which are viable, 7B2-null mutants die early in life from Cushing's disease due to corticotropin ('ACTH') hypersecretion by the neurointermediate lobe, suggesting a possible involvement of 7B2 in secretory granule formation and in secretion regulation. The mechanism of this regulation is yet to be elucidated. 7B2 has been shown to be a good marker of several neuroendocrine cell dysfunctions in humans. The possibility that anomalies in its structure and expression could be aetiological causes of some of these dysfunctions warrants investigation. PMID:11439082

  10. Expression and purification of recombinant proteins in Escherichia coli tagged with the metal-binding protein CusF.

    PubMed

    Cantu-Bustos, J Enrique; Vargas-Cortez, Teresa; Morones-Ramirez, Jose Ruben; Balderas-Renteria, Isaias; Galbraith, David W; McEvoy, Megan M; Zarate, Xristo

    2016-05-01

    Production of recombinant proteins in Escherichia coli has been improved considerably through the use of fusion proteins, because they increase protein solubility and facilitate purification via affinity chromatography. In this article, we propose the use of CusF as a new fusion partner for expression and purification of recombinant proteins in E. coli. Using a cell-free protein expression system, based on the E. coli S30 extract, Green Fluorescent Protein (GFP) was expressed with a series of different N-terminal tags, immobilized on self-assembled protein microarrays, and its fluorescence quantified. GFP tagged with CusF showed the highest fluorescence intensity, and this was greater than the intensities from corresponding GFP constructs that contained MBP or GST tags. Analysis of protein production in vivo showed that CusF produces large amounts of soluble protein with low levels of inclusion bodies. Furthermore, fusion proteins can be exported to the cellular periplasm, if CusF contains the signal sequence. Taking advantage of its ability to bind copper ions, recombinant proteins can be purified with readily available IMAC resins charged with this metal ion, producing pure proteins after purification and tag removal. We therefore recommend the use of CusF as a viable alternative to MBP or GST as a fusion protein/affinity tag for the production of soluble recombinant proteins in E. coli. PMID:26805756

  11. Expression of epithelial adhesion proteins and integrins in chronic inflammation.

    PubMed Central

    Haapasalmi, K.; Mäkelä, M.; Oksala, O.; Heino, J.; Yamada, K. M.; Uitto, V. J.; Larjava, H.

    1995-01-01

    Epithelial cell behavior in chronic inflammation is poorly characterized. During inflammation of tooth-supporting structures (periodontal disease), increased proliferation of epithelial cells into the inflamed connective tissue stroma is commonly seen. In some areas ulceration and degeneration take place. We studied alterations in the expression of adhesion molecules and integrins during chronic periodontal inflammation. In inflamed tissue, laminin-1 and type IV collagen were still present in the basement membrane and surrounding blood vessels, but they were also found extravascularly in inflamed connective tissue stroma. Type VII collagen and laminin-5 (also known as kalinin, epiligrin, or nicein) were poorly preserved in the basement membrane zone, but both were found in unusual streak-like distributions in the subepithelial connective tissue stroma in inflamed tissue. Both fibronectin and tenascin were substantially decreased in chronically inflamed connective tissue, showing only punctate staining at the basement membrane zone. Integrins of the beta 1 family showed two distinct staining patterns in epithelial cells during chronic inflammation; focal losses of beta 1 integrins (alpha 2 beta 1 and alpha 3 beta 1) were found in most areas, while in other areas the entire pocket epithelium was found to be strongly positive for beta 1 integrins. No members of the alpha v integrin family were found in any epithelia studied. Expression of the alpha 6 beta 4 integrin was high in basal cells of healthy tissue, but weak in epithelium associated with chronic inflammation. Chronic inflammation therefore involves alterations in both adhesion proteins and integrins expressed by epithelial cells. Basement membrane components found at abnormal sites in stroma in chronic inflammation might serve as new adhesive ligands for various cell types in inflamed stroma. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 PMID:7541610

  12. Trichohyalin-like 1 protein, a member of fused S100 proteins, is expressed in normal and pathologic human skin.

    PubMed

    Yamakoshi, Takako; Makino, Teruhiko; Ur Rehman, Mati; Yoshihisa, Yoko; Sugimori, Michiya; Shimizu, Tadamichi

    2013-03-01

    Trichohyalin-like 1 (TCHHL1) protein is a novel member of the fused-type S100 protein gene family. The deduced amino acid sequence of TCHHL1 contains an EF-hand domain in the N-terminus, one trans-membrane domain and a nuclear localization signal. We generated specific antibodies against the C-terminus of the TCHHL1 protein and examined the expression of TCHHL1 proteins in normal and pathological human skin. An immunohistochemical study showed that TCHHL1 proteins were expressed in the basal layer of the normal epidermis. In addition, signals of TCHHL1 proteins were observed around the nuclei of cultured growing keratinocytes. Accordingly, TCHHL1 mRNA has been detected in normal skin and cultured growing keratinocytes. Furthermore, TCHHL1 proteins were strongly expressed in the peripheral areas of tumor nests in basal cell carcinomas and squamous cell carcinomas. A dramatic increase in the number of Ki67 positive cells was observed in TCHHL1-expressing areas. The expression of TCHHL1 proteins also increased in non-cancerous hyperproliferative epidermal tissues such as those of psoriasis vulgaris and lichen planus. These findings highlight the possibility that TCHHL1 proteins are expressed in growing keratinocytes of the epidermis and might be associated with the proliferation of keratinocytes. PMID:23376073

  13. Differential dissolved protein expression throughout the life cycle of Giardia lamblia.

    PubMed

    Lingdan, Li; Pengtao, Gong; Wenchao, Li; Jianhua, Li; Ju, Yang; Chengwu, Liu; He, Li; Guocai, Zhang; Wenzhi, Ren; Yujiang, Chen; Xichen, Zhang

    2012-12-01

    Giardia lamblia (G. lamblia) has a simple life cycle that alternates between a cyst and a trophozoite, and this parasite is an important human and animal pathogen. To increase our understanding of the molecular basis of the G. lamblia encystment, we have analyzed the soluble proteins expressed by trophozoites and cysts extracted from feces by quantitative proteomic analysis. A total of 63 proteins were identified by isobaric tags for relative and absolute quantitation (iTRAQ) labeling, and were categorized as cytoskeletal proteins, a cell-cycle-specific kinase, metabolic enzymes and stress resistance proteins. Importantly, we demonstrated that the expression of seven proteins differed significantly between trophozoites and cysts. In cysts, the expression of three proteins (one variable surface protein (VSP), ornithine carbamoyltransferase (OTC), β-tubulin) increased, whereas the expression of four proteins (14-3-3 protein, α-tubulin, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), protein disulfide isomerase 2 (PDI-2)) decreased significantly when compared with the levels of these proteins in trophozoites. The mRNA expression patterns of four of these proteins (OTC, α-tubulin, GAPDH, VSP) were similar to the expression levels of the proteins. These seven proteins appear to play an important role in the completion of the life cycle of G. lamblia. PMID:23058231

  14. Expression and purification of toxic anti-breast cancer p28-NRC chimeric protein

    PubMed Central

    Soleimani, Meysam; Mirmohammad-Sadeghi, Hamid; Sadeghi-Aliabadi, Hojjat; Jahanian-Najafabadi, Ali

    2016-01-01

    Background: Chimeric proteins consisting of a targeting moiety and a cytotoxic moiety are now under intense research focus for targeted therapy of cancer. Here, we report cloning, expression, and purification of such a targeted chimeric protein made up of p28 peptide as both targeting and anticancer moiety fused to NRC peptide as a cytotoxic moiety. However, since the antimicrobial activity of the NRC peptide would intervene expression of the chimeric protein in Escherichia coli, we evaluated the effects of two fusion tags, that is, thioredoxin (Trx) and 6x-His tags, and various expression conditions, on the expression of p28-NRC chimeric protein. Materials and Methods: In order to express the chimeric protein with only 6x-His tag, pET28 expression plasmid was used. Cloning in pET32 expression plasmid was performed to add both Trx and 6x-His tags to the chimeric protein. Expression of the chimeric protein with both plasmids was evaluated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot analysis following optimization of expression conditions and host strains. Results: Expression of the chimeric protein in pET28a was performed. However, expression yield of the chimeric protein was low. Optimization of culture conditions and host strains led to reasonable expression yield of the toxic chimeric protein in pET32a vector. In cases of both plasmids, approximately 10 kDa deviation of the apparent molecular weight from the theoretical one was seen in SDS-PAGE of purified chimeric proteins. Conclusions: The study leads to proper expression and purification yield of p28-NRC chimeric protein with Trx tag following optimizing culture conditions and host strains. PMID:27169101

  15. The Up-Regulation of Ribosomal Proteins Further Regulates Protein Expression Profile in Female Schistosoma japonicum after Pairing

    PubMed Central

    Sun, Jun; Li, Chen; Wang, Suwen

    2015-01-01

    Background Pairing of Schistosoma males and females leads to and maintains female sexual maturation. However, the mechanism by which pairing facilitates sexual maturation of females is not clear. An increasing body of evidence suggests that ribosomal proteins have regulatory rather than constitutive roles in protein translation. Methodology/Principal Findings To investigate the effect of ribosome regulation on female sex maturation, Solexa and iTRAQ techniques were used to analyze the relationship between ribosomal gene or protein expression and sexual development of Schistosoma females. In the present study, considerably higher number of ribosomal genes or proteins were found to be differentially expressed in paired 23-day-old females. Moreover, mature female-specific proteins associated with egg production, such as ferritin-1 heavy chain and superoxide dismutase, were selectively highly expressed in paired females, rather than higher level of protein synthesis of all transcripts compared with those in unpaired 23-day-old females. Furthermore, other developmental stages were utilized to investigate different expression pattern of ribosomal proteins in females by analysing 18-day-old female schistosomula from single- or double-sex infections to determine the relationship between ribosomal protein expression pattern and development. Results showed that undeveloped 18-day-old females from single- and double-sex infections, as well as 23-day-old unpaired females, possessed similar ribosomal protein expression patterns, which were distinct from those in 23-day-old paired females. Conclusions/Significance Our findings reveal that the pairing of females and males triggers a specialized ribosomal protein expression profile which further regulates the protein profile for sexual maturation in Schistosoma japonicum, based on its gene expression profile. PMID:26070205

  16. Use of high-throughput protein array for profiling of differentially expressed proteins in normal and malignant breast tissue.

    PubMed

    Hudelist, Gernot; Pacher-Zavisin, Margit; Singer, Christian F; Holper, Tina; Kubista, Ernst; Schreiber, Martin; Manavi, Mahmood; Bilban, Martin; Czerwenka, Klaus

    2004-08-01

    cDNA arrays provide a powerful tool to identify gene expression pattern that are potentially associated with tumor invasion and metastasis. However, genes work at the protein level and, since the transcriptional activity of a gene does not necessarily reflect cellular protein expression, the identification and quantification of proteins is essential for the understanding of molecular events leading to malignant transformation. We have therefore employed a high-throughput protein microarray system which contains 378 well-characterized monoclonal antibodies in order to compare the gene expression pattern of malignant and adjacent normal breast tissue in a patient with primary breast cancer. Using this technique, we have identified a number of proteins that show increased expression levels in malignant breast tissues such as casein kinase Ie, p53, annexin XI, CDC25C, eIF-4E and MAP kinase 7. The expression of other proteins, such as the multifunctional regulator 14-3-3e was found to be decreased in malignant breast tissue, whereas the majority of proteins remained unchanged when compared to the corresponding non-malignant samples. The protein expression pattern was confirmed by immunohistochemistry, in which antibodies against 8 representative proteins known to be involved in carcinogenesis were employed in paraffin-embedded normal and malignant tissue sections deriving from the same patient. In each case, the results obtained by IHC matched the data obtained by antibody microarray system. Taken together, we have described for the first time a tumor cell specificity protein expression pattern by use of a novel commercially available antibody microarray system. We have thus demonstrated the feasibility of high-throughput protein arrays in the proteomic analysis of human breast tissue. We hypothesize that the use of protein arrays will not only increase our understanding of the molecular events, but could prove useful in evaluating prognosis and in determining optimal

  17. A set of ligation-independent expression vectors for co-expression of proteins in Escherichia coli.

    PubMed

    Chanda, Pranab K; Edris, Wade A; Kennedy, Jeffrey D

    2006-05-01

    A set of ligation-independent expression vectors system has been developed for co-expression of proteins in Escherichia coli. These vectors contain a strong T7 promoter, different drug resistant genes, and an origin of DNA replication from a different incompatibility group, allowing combinations of these plasmids to be stably maintained together. In addition, these plasmids also contain the lacI gene, a transcriptional terminator, and a 3' polyhistidine (6x His) affinity tag (H6) for easy purification of target proteins. All of these vectors contain an identical transportable cassette flanked by suitable restriction enzyme cleavage sites for easy cloning and shuttling among different vectors. This cassette incorporates a ligation-independent cloning (LIC) site for LIC manipulations, an optimal ribosome binding site for efficient protein translation, and a 6x His affinity tag for protein purification Therefore, any E. coli expression vector of choice can be easily converted to LIC type expression vectors by shuttling the cassette using the restriction enzyme cleavage sites at the ends. We have demonstrated the expression capabilities of these vectors by co-expressing three bacterial (dsbA, dsbG, and Trx) and also two other mammalian proteins (KChIP1 and Kv4.3). We further show that co-expressed KChIP1/Kv4.3 forms soluble protein complexes that can be purified for further studies. PMID:16325426

  18. SP PROTEINS AND RUNX2 MEDIATE REGULATION OF MATRIX GLA PROTEIN (MGP) EXPRESSION BY PARATHYROID HORMONE

    PubMed Central

    Suttamanatwong, Supaporn; Jensen, Eric D; Shilling, Jody; Franceschi, Renny T.; Carlson, Ann E.; Mansky, Kim C.; Gopalakrishnan, Rajaram

    2009-01-01

    As part of its catabolic action in bone, parathyroid hormone (PTH) inhibits extracellular matrix mineralization. We previously showed that PTH dose-dependently induces matrix gla protein (MGP) expression in osteoblasts and this induction is at least partially responsible for PTH-mediated inhibition of mineralization. Recently, we identified PKA and ERK/MAPK as the key signaling pathways involved in PTH regulation of MGP expression. The goal of this study was to further characterize the mechanism by which PTH stimulates expression of MGP. Deletion analysis of the murine Mgp gene promoter identified a PTH-responsive region between -173 bp and -49 bp. Using gel-mobility shift assays we found that Sp1, Sp3 and Runx2 bind to distinct sites within this region. Mutation of either the Sp or the Runx2 site reduced MGP induction by PTH, while mutation of both sites completely abolished PTH responsiveness. Overexpression of Runx2 or Sp1 activated the Mgp reporter, while Sp3 was a dose-dependent repressor of MGP expression. Collectively, these data show that PTH regulates MGP gene transcription in osteoblasts through altered activities of Sp and Runx2 transcription factors. PMID:19306294

  19. Cloning, expression, and antigenic characterization of recombinant protein of Mycoplasma gallisepticum expressed in Escherichia coli.

    PubMed

    Rocha, T S; Tramuta, C; Catania, S; Matucci, A; Giuffrida, M G; Baro, C; Profiti, M; Bertolotti, L; Rosati, S

    2015-04-01

    Mycoplasma gallisepticum (MG) is a member of the most important avian mycoplasmas, causing chronic respiratory disease in chickens and leading to important economic losses in the poultry industry. Recombinant technology represents a strategic approach used to achieve highly reliable and specific diagnostic tests in veterinary diseases control: in particular this aspect is crucial for confirming mycoplasma infection and for maintaining mycoplasma-free breeder flocks. In this study, we identified a component of the pyruvate dehydrogenase dihydrolipoamide acetyltransferase (i.e., E2) protein by 2-dimensional electrophoresis (2-DE), characterized it in immunoblotting assays, and analyzed its recombinant (r-E2) in a rec-ELISA test. For full-length protein expression in Escherichia coli (EC) a point mutation was introduced. A rabbit antiserum produced against r-E2 was tested in a Western Blot using different samples of Mycoplasma species. The results showed the applicability of site-directed mutagenesis, with a good yield of the r-E2 after purification. Also, anti-E2 serum reacted with all the tested MG strains showing no cross reaction with other mycoplasmas. The developed E2 ELISA test was capable of detecting MG antibodies in the sera examined. Those results demonstrate the antigenic stability of the E2 protein which could represent a recombinant antigen with potential diagnostic applications. PMID:25667423

  20. Differentially expressed proteins associated with Fusarium head blight resistance in wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fusarium head blight (FHB), mainly caused by Fusarium graminearum, substantially reduces wheat grain yield and quality worldwide. Proteins play important roles in defense against the fungal infection. This study characterized differentially expressed proteins between near-isogenic lines (NILs) contr...

  1. An Approach to Heterologous Expression of Membrane Proteins. The Case of Bacteriorhodopsin

    PubMed Central

    Round, Ekaterina; Shevchenko, Vitaly; Gushchin, Ivan; Polovinkin, Vitaly; Borshchevskiy, Valentin; Gordeliy, Valentin

    2015-01-01

    Heterologous overexpression of functional membrane proteins is a major bottleneck of structural biology. Bacteriorhodopsin from Halobium salinarum (bR) is a striking example of the difficulties in membrane protein overexpression. We suggest a general approach with a finite number of steps which allows one to localize the underlying problem of poor expression of a membrane protein using bR as an example. Our approach is based on constructing chimeric proteins comprising parts of a protein of interest and complementary parts of a homologous protein demonstrating advantageous expression. This complementary protein approach allowed us to increase bR expression by two orders of magnitude through the introduction of two silent mutations into bR coding DNA. For the first time the high quality crystals of bR expressed in E. Coli were obtained using the produced protein. The crystals obtained with in meso nanovolume crystallization diffracted to 1.67 Å. PMID:26046789

  2. p53 protein expression in human breast carcinoma: relationship to expression of epidermal growth factor receptor, c-erbB-2 protein overexpression, and oestrogen receptor.

    PubMed Central

    Poller, D. N.; Hutchings, C. E.; Galea, M.; Bell, J. A.; Nicholson, R. A.; Elston, C. W.; Blamey, R. W.; Ellis, I. O.

    1992-01-01

    The expression of p53 protein, oestrogen receptor protein, epidermal growth factor receptor (EGFR) and overexpression of the c-erbB-2 oncoprotein was examined in a series of 149 primary symptomatic breast carcinomas. Expression of p53 was present in 62 of 146 cases (42.5%) of the invasive carcinoma and one of three cases (33.3%) of ductal carcinoma in situ (DCIS) examined. Statistical associations of tumour oestrogen receptor positivity and lack of p53 protein expression, chi 2 = 19.78 (d.f. = 1), P less than 0.001, positive tumour p53 status and poor tumour grade; chi 2 = 14.1 (d.f. = 2), P less than 0.001, EGFR expression chi 2 = 7.07, (d.f. = 1), P less than 0.01 and tumour c-erbB-2 protein overexpression; chi 2 = 4.61 (d.f. = 1), P = 0.032 were identified. Expression of p53 is rare in invasive lobular carcinoma of classical type (8.3% of cases examined) in contrast to other common types of mammary carcinoma. Non-significant trends of p53 protein expression and increased regional tumour recurrence; chi 2 = 3.20 (d.f. = 1), P = 0.074 and also poorer patient survival; chi 2 = 3.76 (d.f. = 1), P = 0.053 were identified. p53 protein expression is a common event in human breast cancer and is present in both DCIS and invasive mammary carcinoma. Abnormal expression of p53 protein is a feature of both in situ and invasive breast carcinoma, implying that the abnormal p53 protein expression may be implicated in the early stages of mammary carcinoma progression. Images Figure 1 PMID:1355662

  3. Proteasome dysfunction inhibits surfactant protein gene expression in lung epithelial cells: mechanism of inhibition of SP-B gene expression.

    PubMed

    Das, Aparajita; Boggaram, Vijayakumar

    2007-01-01

    Surfactant proteins maintain lung function through their actions to reduce alveolar surface tension and control of innate immune responses in the lung. The ubiquitin proteasome pathway is responsible for the degradation of majority of intracellular proteins in eukaryotic cells, and proteasome dysfunction has been linked to the development of neurodegenerative, cardiac, and other diseases. Proteasome function is impaired in interstitial lung diseases associated with surfactant protein C (SP-C) mutation mapping to the BRICHOS domain located in the proSP-C protein. In this study we determined the effects of proteasome inhibition on surfactant protein expression in H441 and MLE-12 lung epithelial cells to understand the relationship between proteasome dysfunction and surfactant protein gene expression. Proteasome inhibitors lactacystin and MG132 reduced the levels of SP-A, SP-B, and SP-C mRNAs in a concentration-dependent manner in H441 and MLE-12 cells. In H441 cells, lactacystin and MG132 inhibition of SP-B mRNA was associated with similar decreases in SP-B protein, and the inhibition was due to inhibition of gene transcription. Proteasome inhibitors decreased thyroid transcription factor-1 (TTF-1)/Nkx2.1 DNA binding activity, and the reduced TTF-1 DNA binding activity was due to reduced expression levels of TTF-1 protein. These data indicated that the ubiquitin proteasome pathway is essential for the maintenance of surfactant protein gene expression and that disruption of this pathway inhibits surfactant protein gene expression via reduced expression of TTF-1 protein. PMID:16905641

  4. Expression and purification of SARS coronavirus proteins using SUMO-fusions.

    PubMed

    Zuo, Xun; Mattern, Michael R; Tan, Robin; Li, Shuisen; Hall, John; Sterner, David E; Shoo, Joshua; Tran, Hiep; Lim, Peter; Sarafianos, Stefan G; Kazi, Lubna; Navas-Martin, Sonia; Weiss, Susan R; Butt, Tauseef R

    2005-07-01

    Severe acute respiratory syndrome coronavirus (SARS-CoV) proteins belong to a large group of proteins that is difficult to express in traditional expression systems. The ability to express and purify SARS-CoV proteins in large quantities is critical for basic research and for development of pharmaceutical agents. The work reported here demonstrates: (1) fusion of SUMO (small ubiquitin-related modifier), a 100 amino acid polypeptide, to the N-termini of SARS-CoV proteins dramatically enhances expression in Escherichia coli cells and (2) 6x His-tagged SUMO-fusions facilitate rapid purification of the viral proteins on a large scale. We have exploited the natural chaperoning properties of SUMO to develop an expression system suitable for proteins that cannot be expressed by traditional methodologies. A unique feature of the system is the SUMO tag, which enhances expression, facilitates purification, and can be efficiently cleaved by a SUMO-specific protease to generate native protein with a desired N-terminus. We have purified various SARS-CoV proteins under either native or denaturing conditions. These purified proteins have been used to generate highly specific polyclonal antibodies. Our study suggests that the SUMO-fusion technology will be useful for enhancing expression and purification of the viral proteins for structural and functional studies as well as for therapeutic uses. PMID:15939295

  5. RRE-dependent HIV-1 Env RNA effects on Gag protein expression, assembly and release

    SciTech Connect

    López, Claudia S.; Sloan, Rachel; Cylinder, Isabel; Kozak, Susan L.; Kabat, David; Barklis, Eric

    2014-08-15

    The HIV-1 Gag proteins are translated from the full-length HIV-1 viral RNA (vRNA), whereas the envelope (Env) protein is translated from incompletely spliced Env mRNAs. Nuclear export of vRNAs and Env mRNAs is mediated by the Rev accessory protein which binds to the rev-responsive element (RRE) present on these RNAs. Evidence has shown there is a direct or indirect interaction between the Gag protein, and the cytoplasmic tail (CT) of the Env protein. Our current work shows that env gene expression impacts HIV-1 Gag expression and function in two ways. At the protein level, full-length Env expression altered Gag protein expression, while Env CT-deletion proteins did not. At the RNA level, RRE-containing Env mRNA expression reduced Gag expression, processing, and virus particle release from cells. Our results support models in which Gag is influenced by the Env CT, and Env mRNAs compete with vRNAs for nuclear export. - Highlights: • At the protein level, full-length HIV-1 Env alters Gag protein expression. • HIV-1 Env RNA expression reduces Gag levels and virus release. • Env RNA effects on Gag are dependent on the RRE. • RRE-containing Env RNAs compete with vRNAs for nuclear export.

  6. High-throughput instant quantification of protein expression and purity based on photoactive yellow protein turn off/on label.

    PubMed

    Kim, Youngmin; Ganesan, Prabhakar; Ihee, Hyotcherl

    2013-08-01

    Quantifying the concentration and purity of a target protein is essential for high-throughput protein expression test and rapid screening of highly soluble proteins. However, conventional methods such as PAGE and dot blot assay generally involve multiple time-consuming tasks requiring hours or do not allow instant quantification. Here, we demonstrate a new method based on the Photoactive yellow protein turn Off/On Label (POOL) system that can instantly quantify the concentration and purity of a target protein. The main idea of POOL is to use Photoactive Yellow Protein (PYP), or its miniaturized version, as a fusion partner of the target protein. The characteristic blue light absorption and the consequent yellow color of PYP is absent when initially expressed without its chromophore, but can be turned on by binding its chromophore, p-coumaric acid. The appearance of yellow color upon adding a precursor of chromophore to the co-expressed PYP can be used to check the expression amount of the target protein via visual inspection within a few seconds as well as to quantify its concentration and purity with the aid of a spectrometer within a few minutes. The concentrations measured by the POOL method, which usually takes a few minutes, show excellent agreement with those by the BCA Kit, which usually takes ∼1 h. We demonstrate the applicability of POOL in E. coli, insect, and mammalian cells, and for high-throughput protein expression screening. PMID:23740751

  7. Expression of liver fatty acid binding protein in hepatocellular carcinoma.

    PubMed

    Cho, Soo-Jin; Ferrell, Linda D; Gill, Ryan M

    2016-04-01

    Loss of expression of liver fatty acid binding protein (LFABP) by immunohistochemistry has been shown to be characteristic of a subset of hepatocellular adenomas (HCAs) in which HNF1A is inactivated. Transformation to hepatocellular carcinoma is thought to be a very rare phenomenon in the HNF1A-inactivated variant of HCA. However, we recently observed 2 cases at our institution, 1 definite hepatocellular carcinoma and 1 possible hepatocellular carcinoma, with loss of LFABP staining, raising the possibility that LFABP down-regulation may be associated with hepatocellular carcinogenesis. Our aim was to evaluate hepatocellular carcinomas arising in various backgrounds and with varying degrees of differentiation for loss of LFABP staining. Twenty total cases of hepatocellular carcinoma were examined. Thirteen cases arose in a background of cirrhosis due to hepatitis C (n = 8) or steatohepatitis (n = 5); 7 cases arose in a noncirrhotic background, with 2 cases arising within HNF1A-inactivated variant HCA and 2 cases arising within inflammatory variant HCA. Complete loss of expression of LFABP was seen in 6 of 20 cases, including 2 cases of hepatocellular carcinoma arising within HNF1A-inactivated variant HCA. Thus, loss of staining for LFABP appears to be common in hepatocellular carcinoma and may be seen in well-differentiated hepatocellular carcinoma. Therefore, LFABP loss should not be interpreted as evidence for hepatocellular adenoma over carcinoma, when other features support a diagnosis of hepatocellular carcinoma. The findings raise consideration for a role of HNF1A inactivation in hepatocellular carcinogenesis, particularly in less differentiated tumors. PMID:26997447

  8. Identities of Sequestered Proteins in Aggregates from Cells with Induced Polyglutamine Expression

    PubMed Central

    Suhr, Steven T.; Senut, Marie-Claude; Whitelegge, Julian P.; Faull, Kym F.; Cuizon, Denise B.; Gage, Fred H.

    2001-01-01

    Proteins with expanded polyglutamine (polyQ) tracts have been linked to neurodegenerative diseases. One common characteristic of expanded-polyQ expression is the formation of intracellular aggregates (IAs). IAs purified from polyQ-expressing cells were dissociated and studied by protein blot assay and mass spectrometry to determine the identity, condition, and relative level of several proteins sequestered within aggregates. Most of the sequestered proteins comigrated with bands from control extracts, indicating that the sequestered proteins were intact and not irreversibly bound to the polyQ polymer. Among the proteins found sequestered at relatively high levels in purified IAs were ubiquitin, the cell cycle–regulating proteins p53 and mdm-2, HSP70, the global transcriptional regulator Tata-binding protein/TFIID, cytoskeleton proteins actin and 68-kD neurofilament, and proteins of the nuclear pore complex. These data reveal that IAs are highly complex structures with a multiplicity of contributing proteins. PMID:11309410

  9. Heterochromatin Protein 1 Binding Protein 3 Expression as a Candidate Marker of Intrinsic 5-Fluorouracil Resistance

    PubMed Central

    HADAC, JAMIE N.; MILLER, DEVON D.; GRIMES, IAN C.; CLIPSON, LINDA; NEWTON, MICHAEL A.; SCHELMAN, WILLIAM R.; HALBERG, RICHARD B.

    2016-01-01

    Background Despite receiving post-operative 5-fluorouracil (5-FU)-based chemotherapy, approximately 50% of patients with stage IIIC colon cancer experience recurrence. Currently, no molecular signature can predict response to 5-FU. Materials and Methods Mouse models of colon cancer have been developed and characterized. Individual tumors in these mice can be longitudinally monitored and assessed to identify differences between those that are responsive and those that are resistant to therapy. Gene expression was analyzed in serial biopsies that were collected before and after treatment with 5-FU. Colon tumors had heterogeneous responses to treatment with 5-FU. Microarray analysis of pretreatment biopsies revealed that Hp1bp3, a gene encoding heterochromatin protein 1 binding protein 3, was differentially expressed between sensitive and resistant tumors. Conclusion Using mouse models of human colorectal cancer, Hp1bp3 was identified as a candidate marker of intrinsic 5-FU resistance and may represent a potential biomarker for patient stratification or a target of clinical importance. PMID:26976970

  10. Differential expression of hemolymph proteins between susceptible and insecticide-resistant Blattella germanica (Blattodea: Blattellidae).

    PubMed

    Zhang, F; Wang, X J; Huang, Y H; Zhao, Z G; Zhang, S S; Gong, X S; Xie, L; Kang, D M; Jing, X

    2014-08-01

    A proteomic approach combining two-dimensional polyacrylamide gel electrophoresis and tandem mass spectrometry was used to compare hemolymph expression profiles of a beta-cypermethrin-resistant Blattella germanica L. strain and a beta-cypermethrin-susceptible strain. Twenty-eight hemolymph proteins were differentially expressed in the resistant cockroach strain; 19 proteins were upregulated and 9 proteins were downregulated compared with the susceptible strain. Protein identification indicated that expression of putative cuticular protein, nitric oxide synthase, triosephosphate isomerase, alpha-amylase, ABC transporter, and Per a 3 allergen was elevated, and expression of arginine kinase and glycosidase was reduced. The differential expression of these proteins reflects the overall change in cellular structure and metabolism related to the resistance of pyrethroid insecticides. PMID:25182623

  11. Expression Screening of Integral Membrane Proteins by Fusion to Fluorescent Reporters.

    PubMed

    Bird, Louise E; Nettleship, Joanne E; Järvinen, Valtteri; Rada, Heather; Verma, Anil; Owens, Raymond J

    2016-01-01

    The production of recombinant integral membrane proteins for structural and functional studies remains technically challenging due to their relatively low levels of expression. To address this problem, screening strategies have been developed to identify the optimal membrane sequence and expression host for protein production. A common approach is to genetically fuse the membrane protein to a fluorescent reporter, typically Green Fluorescent Protein (GFP) enabling expression levels, localization and detergent solubilisation to be assessed. Initially developed for screening the heterologous expression of bacterial membrane proteins in Escherichia coli, the method has been extended to eukaryotic hosts, including insect and mammalian cells. Overall, GFP-based expression screening has made a major impact on the number of membrane protein structures that have been determined in the last few years. PMID:27553231

  12. Expression of recombinant protein using Corynebacterium Glutamicum: progress, challenges and applications.

    PubMed

    Liu, Xiuxia; Yang, Yankun; Zhang, Wei; Sun, Yang; Peng, Feng; Jeffrey, Laura; Harvey, Linda; McNeil, Brian; Bai, Zhonghu

    2016-08-01

    Corynebacterium glutamicum (C. glutamicum) is a highly promising alternative prokaryotic host for recombinant protein expression, as it possesses several significant advantages over Escherichia coli (E. coli), the currently leading bacterial protein expression system. During the past decades, several experimental techniques and vector components for genetic manipulation of C. glutamicum have been developed and validated, including strong promoters for tightly regulating target gene expression, various types of plasmid vectors, protein secretion systems and methods of genetically modifying the host strain genome to improve protein production potential. This review critically discusses current progress in establishing C. glutamicum as a host for recombinant protein expression, and examines, in depth, some successful case studies of actual application of this expression system. The established "expression tool box" for developing novel constructs based on C. glutamicum as a host are also evaluated. Finally, the existing issues and solutions in process development with C. glutamicum as a host are specifically addressed. PMID:25714007

  13. Co-expression of protein tyrosine kinases EGFR-2 and PDGFRβ with protein tyrosine phosphatase 1B in Pichia pastoris.

    PubMed

    Tu, Pham Ngoc; Wang, Yamin; Cai, Menghao; Zhou, Xiangshan; Zhang, Yuanxing

    2014-02-28

    The regulation of protein tyrosine phosphorylation is mediated by protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs) and is essential for cellular homeostasis. Coexpression of PTKs with PTPs in Pichia pastoris was used to facilitate the expression of active PTKs by neutralizing their apparent toxicity to cells. In this study, the gene encoding phosphatase PTP1B with or without a blue fluorescent protein or peroxisomal targeting signal 1 was cloned into the expression vector pAG32 to produce four vectors. These vectors were subsequently transformed into P. pastoris GS115. The tyrosine kinases EGFR-2 and PDGFRβ were expressed from vector pPIC3.5K and were fused with a His-tag and green fluorescent protein at the N-terminus. The two plasmids were transformed into P. pastoris with or without PTP1B, resulting in 10 strains. The EGFR-2 and PDGFRβ fusion proteins were purified by Ni(2+) affinity chromatography. In the recombinant P. pastoris, the PTKs co-expressed with PTP1B exhibited higher kinase catalytic activity than did those expressing the PTKs alone. The highest activities were achieved by targeting the PTKs and PTP1B into peroxisomes. Therefore, the EGFR-2 and PDGFRβ fusion proteins expressed in P. pastoris may be attractive drug screening targets for anticancer therapeutics. PMID:24248091

  14. Surfactant Protein A Expression in Chronic Rhinosinusitis and Atrophic Rhinitis

    PubMed Central

    El-Anwar, Mohammad Waheed; Hamed, Atef A.; Mohamed, Abd ElRaof Said; Nofal, Ahmad Abdel-Fattah; Mohamed, Maha A.; Abdel-Aziz, Hesham R.

    2015-01-01

    Introduction Surfactant protein A (SP-A) exhibits antimicrobial properties and interacts with a variety of respiratory tract pathogens. Objective The objective of this study was to detect the presence of SP-A and measure its alterations in chronic rhinosinusitis (CRS) and primary atrophic rhinitis (PAR) versus healthy controls. Methods Inferior turbinate and sinus mucosal biopsies were taken from 30 patients with CRS, 30 patients with PAR, and 20 healthy controls. Immunohistochemical staining for SP-A and polymerase chain reaction (PCR) amplification of SP-A messenger RNA were performed on nasal tissue samples. Results Immunostaining localized SP-A to the mucosa and submucosal glands in CRS specimens but failed to localize it in PAR specimens. Quantitative PCR showed a high, statistically significant increase in the SP-A levels of patients with CRS when compared with controls (p < 0.0001) and also demonstrated a significant reduction of SP-A in patients with PAR compared with controls (p < 0.005). Conclusion SP-A is significantly increased in CRS and decreased significantly in PAR and appears to be expressed by respiratory epithelial cells and submucosal glandular elements of the sinonasal mucosa. The potential therapeutic applications of surfactant in the enhancement of mucociliary clearance need to be studied. PMID:25992168

  15. Proteomics Based Identification of Cell Migration Related Proteins in HBV Expressing HepG2 Cells

    PubMed Central

    Feng, Huixing; Li, Xi; Chan, Vincent; Chen, Wei Ning

    2014-01-01

    Proteomics study was performed to investigate the specific protein expression profiles of HepG2 cells transfected with mutant HBV compared with wildtype HBV genome, aiming to identify the specific functions of SH3 binding domain (proline rich region) located in HBx. In addition to the cell movement and kinetics changes due to the expression of HBV genome we have observed previously, here we further targeted to explore the specific changes of cellular proteins and potential intracellular protein interactions, which might provide more information of the potential cellular mechanism of the differentiated cell movements. Specific changes of a number of proteins were shown in global protein profiling in HepG2 cells expressing wildtype HBV, including cell migration related proteins, and interestingly the changes were found recovered by SH3 binding domain mutated HBV. The distinctive expressions of proteins were validated by Western blot analysis. PMID:24763314

  16. Cell-specific expression of the carrot EP2 lipid transfer protein gene.

    PubMed Central

    Sterk, P; Booij, H; Schellekens, G A; Van Kammen, A; De Vries, S C

    1991-01-01

    A cDNA corresponding to a 10-kD protein, designated extracellular protein 2 (EP2), that is secreted by embryogenic cell cultures of carrot was obtained by expression screening. The derived protein sequence and antisera against heterologous plant lipid transfer proteins identified the EP2 protein as a lipid transfer protein. Protein gel blot analysis showed that the EP2 protein is present in cell walls and conditioned medium of cell cultures. RNA gel blot analysis revealed that the EP2 gene is expressed in embryogenic cell cultures, the shoot apex of seedlings, developing flowers, and maturing seeds. In situ hybridization showed expression of the EP2 gene in protoderm cells of somatic and zygotic embryos and transient expression in epidermis cells of leaf primordia and all flower organs. In the shoot apical meristem, expression is found in the tunica and lateral zone. In maturing seeds, the EP2 gene is expressed in the outer epidermis of the integument, the seed coat, and the pericarp epidermis, as well as transiently in between both mericarps. Based on the extracellular location of the EP2 protein and the expression pattern of the encoding gene, we propose a role for plant lipid transfer proteins in the transport of cutin monomers through the extracellular matrix to sites of cutin synthesis. PMID:1822991

  17. Connecting protein and mRNA burst distributions for stochastic models of gene expression

    NASA Astrophysics Data System (ADS)

    Elgart, Vlad; Jia, Tao; Fenley, Andrew T.; Kulkarni, Rahul

    2011-08-01

    The intrinsic stochasticity of gene expression can lead to large variability in protein levels for genetically identical cells. Such variability in protein levels can arise from infrequent synthesis of mRNAs which in turn give rise to bursts of protein expression. Protein expression occurring in bursts has indeed been observed experimentally and recent studies have also found evidence for transcriptional bursting, i.e. production of mRNAs in bursts. Given that there are distinct experimental techniques for quantifying the noise at different stages of gene expression, it is of interest to derive analytical results connecting experimental observations at different levels. In this work, we consider stochastic models of gene expression for which mRNA and protein production occurs in independent bursts. For such models, we derive analytical expressions connecting protein and mRNA burst distributions which show how the functional form of the mRNA burst distribution can be inferred from the protein burst distribution. Additionally, if gene expression is repressed such that observed protein bursts arise only from single mRNAs, we show how observations of protein burst distributions (repressed and unrepressed) can be used to completely determine the mRNA burst distribution. Assuming independent contributions from individual bursts, we derive analytical expressions connecting means and variances for burst and steady-state protein distributions. Finally, we validate our general analytical results by considering a specific reaction scheme involving regulation of protein bursts by small RNAs. For a range of parameters, we derive analytical expressions for regulated protein distributions that are validated using stochastic simulations. The analytical results obtained in this work can thus serve as useful inputs for a broad range of studies focusing on stochasticity in gene expression.

  18. Aβ40 Reduces P-Glycoprotein at the Blood–Brain Barrier through the Ubiquitin–Proteasome Pathway

    PubMed Central

    Zhong, Yu; Wolf, Andrea; LeVine, Harry; Miller, David S.; Bauer, Björn

    2016-01-01

    Failure to clear amyloid-β (Aβ) from the brain is in part responsible for Aβ brain accumulation in Alzheimer's disease (AD). A critical protein for clearing Aβ across the blood–brain barrier is the efflux transporter P-glycoprotein (P-gp) in the luminal plasma membrane of the brain capillary endothelium. P-gp is reduced at the blood–brain barrier in AD, which has been shown to be associated with Aβ brain accumulation. However, the mechanism responsible for P-gp reduction in AD is not well understood. Here we focused on identifying critical mechanistic steps involved in reducing P-gp in AD. We exposed isolated rat brain capillaries to 100 nm Aβ40, Aβ40, aggregated Aβ40, and Aβ42. We observed that only Aβ40 triggered reduction of P-gp protein expression and transport activity levels; this occurred in a dose- and time-dependent manner. To identify the steps involved in Aβ-mediated P-gp reduction, we inhibited protein ubiquitination, protein trafficking, and the ubiquitin–proteasome system, and monitored P-gp protein expression, transport activity, and P-gp-ubiquitin levels. Thus, exposing brain capillaries to Aβ40 triggers ubiquitination, internalization, and proteasomal degradation of P-gp. These findings may provide potential therapeutic targets within the blood–brain barrier to limit P-gp degradation in AD and improve Aβ brain clearance. SIGNIFICANCE STATEMENT The mechanism reducing blood–brain barrier P-glycoprotein (P-gp) in Alzheimer's disease is poorly understood. In the present study, we focused on defining this mechanism. We demonstrate that Aβ40 drives P-gp ubiquitination, internalization, and proteasome-dependent degradation, reducing P-gp protein expression and transport activity in isolated brain capillaries. These findings may provide potential therapeutic avenues within the blood–brain barrier to limit P-gp degradation in Alzheimer's disease and improve Aβ brain clearance. PMID:26865616

  19. Analysis of differentially expressed proteins in colorectal cancer using hydroxyapatite column and SDS-PAGE.

    PubMed

    Lim, Shi-Rou; Gooi, Boon-Hui; Singh, Manjit; Gam, Lay-Harn

    2011-11-01

    Limitation on two dimensional (2D) gel electrophoresis technique causes some proteins to be under presented, especially the extreme acidic, basic, or membrane proteins. To overcome the limitation of 2D electrophoresis, an analysis method was developed for identification of differentially expressed proteins in normal and cancerous colonic tissues using self-pack hydroxyapatite (HA) column. Normal and cancerous colon tissues were homogenized and proteins were extracted using sodium phosphate buffer at pH 6.8. Protein concentration was determined and the proteins were loaded unto the HA column. HA column reduced the complexity of proteins mixture by fractionating the proteins according to their ionic strength. Further protein separation was accomplished by a simple and cost effective sodium dodecyl sulfate-polyacrylamide gel electrophoresis method. The protein bands were subjected to in-gel digestion and protein analysis was performed using electrospray ionization (ESI) ion trap mass spectrometer. There were 17 upregulated proteins and seven downregulated proteins detected with significant differential expression. Some of these proteins were low abundant proteins or proteins with extreme pH that were usually under presented in 2D gel analysis. We have identified brain mitochondrial carrier protein 1, T-cell surface glycoprotein CD1a, SOSS complex subunit B2, and Protein Jade 1 which were previously not detected in 2D gel analysis method. PMID:21863284

  20. Expression of chicken CTCF gene in COS-1 cells and partial purification of CTCF protein.

    PubMed

    Kotova, E S; Sorokina, I V; Akopov, S B; Nikolaev, L G; Sverdlov, E D

    2013-08-01

    The chicken gene for transcription factor CTCF was expressed in COS-1 mammalian cells. The CTCF protein containing polyhistidine tag was partially purified using metallo-affinity and ion-exchange chromatography. The expressed protein localized in the cell nucleus and was shown to be functionally active in the electrophoretic mobility shift assay and specifically interacted with anti-CTCF antibodies. PMID:24228875

  1. Maternal low protein diet and postnatal high fat diet increases adipose imprinted gene expression

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maternal and postnatal diet can alter Igf2 gene expression and DNA methylation. To test whether maternal low protein and postnatal high fat (HF) diet result in alteration in Igf2 expression and obesity, we fed obese-prone Sprague-Dawley rats 8% (LP) or 20% (NP) protein for 3 wk prior to breeding and...

  2. Teaching Molecular Biology to Undergraduate Biology Students: An Illustration of Protein Expression and Purification

    ERIC Educational Resources Information Center

    Sommer, Cesar Adolfo; Silva, Flavio Henrique; Novo, Maria Teresa Marques

    2004-01-01

    Practical classes on protein expression and purification were given to undergraduate biology students enrolled in the elective course "Introduction to Genetic Engineering." The heterologous expression of the green fluorescent protein (GFP)* of "Aequorea victoria" is an interesting system for didactic purposes because it can be viewed easily during…

  3. Interaction between Brome Mosaic Virus Proteins and RNAs: Effects on RNA Replication, Protein Expression, and RNA Stability

    PubMed Central

    Gopinath, K.; Dragnea, B.; Kao, C.

    2005-01-01

    Brome mosaic virus (BMV) RNA replication has been examined in a number of systems, including Saccharomyces cerevisiae. We developed an efficient T-DNA-based gene delivery system using Agrobacterium tumefaciens to transiently express BMV RNAs in Nicotiana benthamiana. The expressed RNAs can systemically infect plants and provide material to extract BMV replicase that can perform template-dependent RNA-dependent RNA synthesis in vitro. We also expressed the four BMV-encoded proteins from nonreplicating RNAs and analyzed their effects on BMV RNA accumulation. The capsid protein that coinfiltrated with constructs expressing RNA1 and RNA2 suppressed minus-strand levels but increased plus-strand RNA accumulation. The replication proteins 1a and 2a could function in trans to replicate and transcribe the BMV RNAs. None of the BMV proteins or RNA could efficiently suppress posttranscriptional silencing. However, 1a expressed in trans will suppress the production of a recombinant green fluorescent protein expressed from the nontranslated portions of BMV RNA1 and RNA2, suggesting that 1a may regulate translation from BMV RNAs. BMV replicase proteins 1a did not affect the accumulation of the BMV RNAs in the absence of RNA replication, unlike the situation reported for S. cerevisiae. This work demonstrates that the Agrobacterium-mediated gene delivery system can be used to study the cis- and trans-acting requirements for BMV RNA replication in plants and that significant differences can exist for BMV RNA replication in different hosts. PMID:16254357

  4. Borrelia burgdorferi Proteins Whose Expression Is Similarly Affected by Culture Temperature and pH

    PubMed Central

    Ramamoorthy, Ramesh; Scholl-Meeker, Dorothy

    2001-01-01

    Previously, we had demonstrated the upregulation in the expression of several proteins, including the lipoproteins OspC and P35, of Borrelia burgdorferi in the stationary growth phase. Since the expression of OspC is also known to be affected by culture temperature and pH, we examined the effects of both variables on the expression of the remaining stationary-phase-upregulated proteins. Our study revealed that the expression of each of the remaining stationary-phase-upregulated proteins, P35 included, was also influenced by culture temperature; these proteins were selectively expressed at 34°C but not at 24°C. Significantly, the expression of a majority of these proteins was also affected by culture pH, since they were abundantly expressed at pH 7.0 (resembling the tick midgut pH of 6.8 during feeding) but only sparsely at pH 8.0 (a condition closer to that of the unfed tick midgut pH of 7.4). We propose that this group of B. burgdorferi proteins, which in culture is selectively expressed under conditions of 34°C and pH 7.0, may be induced in the tick midgut during the feeding event. Furthermore, the differential and coordinate expression of these proteins under different environmental conditions suggests that the encoding genes may be coregulated. PMID:11254645

  5. Protein-protein interaction and gene co-expression maps of ARFs and Aux/IAAs in Arabidopsis

    PubMed Central

    Piya, Sarbottam; Shrestha, Sandesh K.; Binder, Brad; Stewart, C. Neal; Hewezi, Tarek

    2014-01-01

    The phytohormone auxin regulates nearly all aspects of plant growth and development. Based on the current model in Arabidopsis thaliana, Auxin/indole-3-acetic acid (Aux/IAA) proteins repress auxin-inducible genes by inhibiting auxin response transcription factors (ARFs). Experimental evidence suggests that heterodimerization between Aux/IAA and ARF proteins are related to their unique biological functions. The objective of this study was to generate the Aux/IAA-ARF protein-protein interaction map using full length sequences and locate the interacting protein pairs to specific gene co-expression networks in order to define tissue-specific responses of the Aux/IAA-ARF interactome. Pairwise interactions between 19 ARFs and 29 Aux/IAAs resulted in the identification of 213 specific interactions of which 79 interactions were previously unknown. The incorporation of co-expression profiles with protein-protein interaction data revealed a strong correlation of gene co-expression for 70% of the ARF-Aux/IAA interacting pairs in at least one tissue/organ, indicative of the biological significance of these interactions. Importantly, ARF4-8 and 19, which were found to interact with almost all Aux-Aux/IAA showed broad co-expression relationships with Aux/IAA genes, thus, formed the central hubs of the co-expression network. Our analyses provide new insights into the biological significance of ARF-Aux/IAA associations in the morphogenesis and development of various plant tissues and organs. PMID:25566309

  6. Enhanced protein expression in the baculovirus/insect cell system using engineered SUMO fusions.

    PubMed

    Liu, Li; Spurrier, Joshua; Butt, Tauseef R; Strickler, James E

    2008-11-01

    Recombinant protein expression in insect cells varies greatly from protein to protein. A fusion tag that is not only a tool for detection and purification, but also enhances expression and/or solubility would greatly facilitate both structure/function studies and therapeutic protein production. We have shown that fusion of SUMO (small ubiquitin-related modifier) to several test proteins leads to enhanced expression levels in Escherichia coli. In eukaryotic expression systems, however, the SUMO tag could be cleaved by endogenous desumoylase. In order to adapt SUMO-fusion technology to these systems, we have developed an alternative SUMO-derived tag, designated SUMOstar, which is not processed by native SUMO proteases. In the present study, we tested the SUMOstar tag in a baculovirus/insect cell system with several proteins, i.e. mouse UBP43, human tryptase beta II, USP4, USP15, and GFP. Our results demonstrate that fusion to SUMOstar enhanced protein expression levels at least 4-fold compared to either the native or His(6)-tagged proteins. We isolated active SUMOstar tagged UBP43, USP4, USP15, and GFP. Tryptase was active following cleavage with a SUMOstar specific protease. The SUMOstar system will make significant impact in difficult-to-express proteins and especially to those proteins that require the native N-terminal residue for function. PMID:18713650

  7. Stress protein expression in early phase spinal cord ischemia/reperfusion injury.

    PubMed

    Zhang, Shanyong; Wu, Dankai; Wang, Jincheng; Wang, Yongming; Wang, Guoxiang; Yang, Maoguang; Yang, Xiaoyu

    2013-08-25

    Spinal cord ischemia/reperfusion injury is a stress injury to the spinal cord. Our previous studies using differential proteomics identified 21 differentially expressed proteins (n > 2) in rabbits with spinal cord ischemia/reperfusion injury. Of these proteins, stress-related proteins included protein disulfide isomerase A3, stress-induced-phosphoprotein 1 and heat shock cognate protein 70. In this study, we established New Zealand rabbit models of spinal cord ischemia/reperfusion injury by abdominal aorta occlusion. Results demonstrated that hind limb function initially improved after spinal cord ischemia/reperfusion injury, but then deteriorated. The pathological morphology of the spinal cord became aggravated, but lessened 24 hours after reperfusion. However, the numbers of motor neurons and interneurons in the spinal cord gradually decreased. The expression of protein disulfide isomerase A3, stress-induced-phosphoprotein 1 and heat shock cognate protein 70 was induced by ischemia/reperfusion injury. The expression of these proteins increased within 12 hours after reperfusion, and then decreased, reached a minimum at 24 hours, but subsequently increased again to similar levels seen at 6-12 hours, showing a characterization of induction-inhibition-induction. These three proteins were expressed only in cytoplasm but not in the nuclei. Moreover, the expression was higher in interneurons than in motor neurons, and the survival rate of interneurons was greater than that of motor neurons. It is assumed that the expression of stress-related proteins exhibited a protective effect on neurons. PMID:25206532

  8. The N Terminus of Andes Virus L Protein Suppresses mRNA and Protein Expression in Mammalian Cells

    PubMed Central

    Heinemann, Patrick; Schmidt-Chanasit, Jonas

    2013-01-01

    Little is known about the structure and function of the 250-kDa L protein of hantaviruses, although it plays a central role in virus genome transcription and replication. When attempting to study Andes virus (ANDV) L protein in mammalian cells, we encountered difficulties. Even in a strong overexpression system, ANDV L protein could not be detected by immunoblotting. Deletion analysis revealed that the 534 N-terminal amino acid residues determine the low-expression phenotype. Inhibition of translation due to RNA secondary structures around the start codon, rapid proteasomal degradation, and reduced half-life time were excluded. However, ANDV L protein expression could be rescued upon mutation of the catalytic PD-E-K motif and further conserved residues of the putative endonuclease at the N terminus of the protein. In addition, wild-type ANDV L rather than expressible L mutants suppressed the level of L mRNA, as well as reporter mRNAs. Wild-type L protein also reduced the synthesis of cellular proteins in the high-molecular-weight range. Using expressible ANDV L mutants as a tool for localization studies, we show that L protein colocalizes with ANDV N and NSs but not Gc protein. A fraction of L protein also colocalized with the cellular processing (P) body component DCP1a. Overall, these data suggest that ANDV L protein possesses a highly active endonuclease at the N terminus suppressing the level of its own as well as heterologous mRNAs upon recombinant expression in mammalian cells. PMID:23576516

  9. Analysis of differential protein expression in normal and neoplastic human breast epithelial cell lines

    SciTech Connect

    Williams, K.; Chubb, C.; Huberman, E.; Giometti, C.S.

    1997-07-01

    High resolution two dimensional get electrophoresis (2DE) and database analysis was used to establish protein expression patterns for cultured normal human mammary epithelial cells and thirteen breast cancer cell lines. The Human Breast Epithelial Cell database contains the 2DE protein patterns, including relative protein abundances, for each cell line, plus a composite pattern that contains all the common and specifically expressed proteins from all the cell lines. Significant differences in protein expression, both qualitative and quantitative, were observed not only between normal cells and tumor cells, but also among the tumor cell lines. Eight percent of the consistently detected proteins were found in significantly (P < 0.001) variable levels among the cell lines. Using a combination of immunostaining, comigration with purified protein, subcellular fractionation, and amino-terminal protein sequencing, we identified a subset of the differentially expressed proteins. These identified proteins include the cytoskeletal proteins actin, tubulin, vimentin, and cytokeratins. The cell lines can be classified into four distinct groups based on their intermediate filament protein profile. We also identified heat shock proteins; hsp27, hsp60, and hsp70 varied in abundance and in some cases in the relative phosphorylation levels among the cell lines. Finally, we identified IMP dehydrogenase in each of the cell lines, and found the levels of this enzyme in the tumor cell lines elevated 2- to 20-fold relative to the levels in normal cells.

  10. Development of Novel Rifampicin-Derived P-Glycoprotein Activators/Inducers. Synthesis, In Silico Analysis and Application in the RBE4 Cell Model, Using Paraquat as Substrate

    PubMed Central

    Vilas-Boas, Vânia; Silva, Renata; Palmeira, Andreia; Sousa, Emília; Ferreira, Luísa Maria; Branco, Paula Sério; Carvalho, Félix; Bastos, Maria de Lourdes; Remião, Fernando

    2013-01-01

    P-glycoprotein (P-gp) is a 170 kDa transmembrane protein involved in the outward transport of many structurally unrelated substrates. P-gp activation/induction may function as an antidotal pathway to prevent the cytotoxicity of these substrates. In the present study we aimed at testing rifampicin (Rif) and three newly synthesized Rif derivatives (a mono-methoxylated derivative, MeORif, a peracetylated derivative, PerAcRif, and a reduced derivative, RedRif) to establish their ability to modulate P-gp expression and activity in a cellular model of the rat’s blood–brain barrier, the RBE4 cell line P-gp expression was assessed by western blot using C219 anti-P-gp antibody. P-gp function was evaluated by flow cytometry measuring the accumulation of rhodamine123. Whenever P-gp activation/induction ability was detected in a tested compound, its antidotal effect was further tested using paraquat as cytotoxicity model. Interactions between Rif or its derivatives and P-gp were also investigated by computational analysis. Rif led to a significant increase in P-gp expression at 72 h and RedRif significantly increased both P-gp expression and activity. No significant differences were observed for the other derivatives. Pre- or simultaneous treatment with RedRif protected cells against paraquat-induced cytotoxicity, an effect reverted by GF120918, a P-gp inhibitor, corroborating the observed P-gp activation ability. Interaction of RedRif with P-gp drug-binding pocket was consistent with an activation mechanism of action, which was confirmed with docking studies. Therefore, RedRif protection against paraquat-induced cytotoxicity in RBE4 cells, through P-gp activation/induction, suggests that it may be useful as an antidote for cytotoxic substrates of P-gp. PMID:23991219

  11. Virus-Derived Vectors for the Expression of Multiple Proteins in Plants.

    PubMed

    Saxena, Pooja; Thuenemann, Eva C; Sainsbury, Frank; Lomonossoff, George P

    2016-01-01

    This chapter constitutes a practical guide to using the "pEAQ" vector series for transient or stable expression of one or more protein(s) in Nicotiana benthamiana plants. The pEAQ vectors are a series of small binary vectors designed for controlled expression of multiple proteins in plants. To achieve high levels of expression, an expression system based on translational enhancement by the untranslated regions of RNA-2 from cowpea mosaic virus (CPMV), named CPMV-HT, is used. The expression vector pEAQ-HT combines the user-friendly pEAQ plasmid with CPMV-HT to provide a system for high-level expression of proteins in plants. PMID:26614280

  12. Quantitative proteomics of Xenopus laevis embryos: expression kinetics of nearly 4000 proteins during early development

    NASA Astrophysics Data System (ADS)

    Sun, Liangliang; Bertke, Michelle M.; Champion, Matthew M.; Zhu, Guijie; Huber, Paul W.; Dovichi, Norman J.

    2014-03-01

    While there is a rich literature on transcription dynamics during the development of many organisms, protein data is limited. We used iTRAQ isotopic labeling and mass spectrometry to generate the largest developmental proteomic dataset for any animal. Expression dynamics of nearly 4,000 proteins of Xenopus laevis was generated from fertilized egg to neurula embryo. Expression clusters into groups. The cluster profiles accurately reflect the major events that mark changes in gene expression patterns during early Xenopus development. We observed decline in the expression of ten DNA replication factors after the midblastula transition (MBT), including a marked decline of the licensing factor XCdc6. Ectopic expression of XCdc6 leads to apoptosis; temporal changes in this protein are critical for proper development. Measurement of expression in single embryos provided no evidence for significant protein heterogeneity between embryos at the same stage of development.

  13. Differential expression of proteins in monozygotic twins with discordance of infantile esotropic phenotypes

    PubMed Central

    Bai, Haiqing; Yan, Zhiyong; Ma, Yuna; Li, Hui

    2011-01-01

    Purpose To identify strabismus-related proteins, we performed proteome analysis in monozygotic twins with discordance of congenital esotropic phenotypes and in normal children. Methods Surface-enhanced laser desorption/ ionization time-of-flight mass spectrometry (SELDI-TOF-MS) technology was used to detect changes in protein expression in a pair of twins with discordant esotropic phenotypes (twin A is orthotropic and twin B is esotropic). In addition, two non-twin esotropic children and two orthotropic children of the same age were chosen. The differentially expressed proteome obtained was validated in twelve non-twin esotropic children and eighteen orthotropic children and compared to the protein database. Results We detected four differentially expressed proteins in monozygotic twins with discordance of congenital esotropic phenotypes. The corresponding molecular weights were 4,146 Da, 4,801 Da, 7,786 Da, and 5,859 Da, respectively. Among these 4 proteins, the first three proteins were down-regulated and the last was upregulated. The initial characterization of these detected proteins via protein library revealed that their characteristics were similar to those of the glucagon precursor, pituitary adenylate cyclase-activating polypeptide (PACAP), camp-dependent protein kinase inhibitor α, and anti-metastasis gene (antigen), respectively. Conclusions There were differentially expressed proteins between monozygotic twins with discordance of congenital esotropic phenotypes and normal children. These differentially expressed proteins were mainly down-regulated in the strabismus patients and may be involved in the occurrence and development of congenital esotropia. PMID:21738391

  14. Interaction of drugs of abuse and maintenance treatments with human P-glycoprotein (ABCB1) and breast cancer resistance protein (ABCG2).

    PubMed

    Tournier, Nicolas; Chevillard, Lucie; Megarbane, Bruno; Pirnay, Stéphane; Scherrmann, Jean-Michel; Declèves, Xavier

    2010-08-01

    Drug interaction with P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) may influence its tissue disposition including blood-brain barrier transport and result in potent drug-drug interactions. The limited data obtained using in-vitro models indicate that methadone, buprenorphine, and cannabinoids may interact with human P-gp; but almost nothing is known about drugs of abuse and BCRP. We used in vitro P-gp and BCRP inhibition flow cytometric assays with hMDR1- and hBCRP-transfected HEK293 cells to test 14 compounds or metabolites frequently involved in addiction, including buprenorphine, norbuprenorphine, methadone, ibogaine, cocaine, cocaethylene, amphetamine, N-methyl-3,4-methylenedioxyamphetamine, 3,4-methylenedioxyamphetamine, nicotine, ketamine, Delta9-tetrahydrocannabinol (THC), naloxone, and morphine. Drugs that in vitro inhibited P-gp or BCRP were tested in hMDR1- and hBCRP-MDCKII bidirectional transport studies. Human P-gp was significantly inhibited in a concentration-dependent manner by norbuprenorphine>buprenorphine>methadone>ibogaine and THC. Similarly, BCRP was inhibited by buprenorphine>norbuprenorphine>ibogaine and THC. None of the other tested compounds inhibited either transporter, even at high concentration (100 microm). Norbuprenorphine (transport efflux ratio approoximately 11) and methadone (transport efflux ratio approoximately 1.9) transport was P-gp-mediated; however, with no significant stereo-selectivity regarding methadone enantiomers. BCRP did not transport any of the tested compounds. However, the clinical significance of the interaction of norbuprenorphine with P-gp remains to be evaluated. PMID:19887017

  15. Verapamil and Rifampin Effect on P-Glycoprotein Expression in Hepatocellular Carcinoma

    PubMed Central

    Jalali, Amir; Ghasemian, Sepideh; Najafzadeh, Hossein; Galehdari, Hamid; Seifi, Masoud Reza; Zangene, Fateme; Dehdardargahi, Shaiesteh

    2014-01-01

    Background: High expression of p-glycoprotein (P-gp) has been associated with a poor prognosis in patients with hepatocellular carcinoma (HCC). It is likely that P-gp overexpression is responsible for multidrug resistance in HCC. Objectives: The aim of this study was to elucidate the effect of potent carcinogen nitrosamine with and without verapamil and rifampin drugs on P-gp expression at the mRNA level in HCC. Materials and Methods: Four groups of rats (n = 5) were selected with different treatments and one group as control. mRNA concentration changes were monitored using quantitative PCR (QPCR). Results: A significant difference was found between verapamil treated group and the control regarding the mRNA level. The mdr1a mRNA was significantly decreased in the verapamil group (P ≤ 0.001). Rifampin administrated group had a decreased level of the mdr1a mRNA compared to the control group (P ≤ 0.006). No significant changes were observed in HCC induced rats regarding the mdr1a mRNA level when treated with verapamil and rifampin. An enhanced expression of the mdr1a gene was found In the HCC induced animals when treated with drugs. Conclusions: Verapamil and rifampin were found specific and effective against P-gp expression in HCC. In conclusion, treatment efficacy of most anticancer drugs is increased in combination with verapamil and rifampin against most advanced HCC. PMID:25625052

  16. Multiplexed expression and screening for recombinant protein production in mammalian cells

    PubMed Central

    Chapple, Susan DJ; Crofts, Anna M; Shadbolt, S Paul; McCafferty, John; Dyson, Michael R

    2006-01-01

    Background A variety of approaches to understanding protein structure and function require production of recombinant protein. Mammalian based expression systems have advantages over bacterial systems for certain classes of protein but can be slower and more laborious. Thus the availability of a simple system for production and rapid screening of constructs or conditions for mammalian expression would be of great benefit. To this end we have coupled an efficient recombinant protein production system based on transient transfection in HEK-293 EBNA1 (HEK-293E) suspension cells with a dot blot method allowing pre-screening of proteins expressed in cells in a high throughput manner. Results A nested PCR approach was used to clone 21 extracellular domains of mouse receptors as CD4 fusions within a mammalian GATEWAY expression vector system. Following transient transfection, HEK-293E cells grown in 2 ml cultures in 24-deep well blocks showed similar growth kinetics, viability and recombinant protein expression profiles, to those grown in 50 ml shake flask cultures as judged by western blotting. Following optimisation, fluorescent dot blot analysis of transfection supernatants was shown to be a rapid method for analysing protein expression yielding similar results as western blot analysis. Addition of urea enhanced the binding of glycoproteins to a nitrocellulose membrane. A good correlation was observed between the results of a plate based small scale transient transfection dot blot pre-screen and successful purification of proteins expressed at the 50 ml scale. Conclusion The combination of small scale multi-well plate culture and dot blotting described here will allow the multiplex analysis of different mammalian expression experiments enabling a faster identification of high yield expression constructs or conditions prior to large scale protein production. The methods for parallel GATEWAY cloning and expression of multiple constructs in cell culture will also be useful

  17. Snorkel: an epitope tagging system for measuring the surface expression of membrane proteins.

    PubMed

    Brown, Michael; Stafford, Lewis J; Onisk, Dale; Joaquim, Tony; Tobb, Alhagie; Goldman, Larissa; Fancy, David; Stave, James; Chambers, Ross

    2013-01-01

    Tags are widely used to monitor a protein's expression level, interactions, protein trafficking, and localization. Membrane proteins are often tagged in their extracellular domains to allow discrimination between protein in the plasma membrane from that in internal pools. Multipass membrane proteins offer special challenges for inserting a tag since the extracellular regions are often composed of small loops and thus inserting an epitope tag risks perturbing the structure, function, or location of the membrane protein. We have developed a novel tagging system called snorkel where a transmembrane domain followed by a tag is appended to the cytoplasmic C-terminus of the membrane protein. In this way the tag is displayed extracellularly, but structurally separate from the membrane protein. We have tested the snorkel tag system on a diverse panel of membrane proteins including GPCRs and ion channels and demonstrated that it reliably allows for monitoring of the surface expression. PMID:24023844

  18. Differential protein expression in human corneal endothelial cells cultured from young and older donors

    PubMed Central

    Zhu, Cheng; Rawe, Ian

    2008-01-01

    Purpose To establish a baseline protein fingerprint of cultured human corneal endothelial cells (HCEC), to determine whether the protein profiles exhibit age-related differences, and to identify proteins differentially expressed in HCEC cultured from young and older donors. Methods Corneas were obtained from five young (<30 years old) and five older donors (>50 years old). HCEC were cultured, and protein was extracted from confluent passage 3 cells. Extracts from each age group were pooled to form two samples. Proteins were separated on two-dimensional (2-D) gels and stained with SyproRuby. Resultant images were compared to identify protein spots that were either similarly expressed or differentially expressed by at least twofold. Protein spots were then identified by matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry. Results Protein spots were well resolved, and patterns were reproducible on 2-D gels using either pH 3–10 or pH 4–7 IPG strips. Two-dimensional gels prepared with pH 4–7 IPG strips were used for differential display analysis, which was reproduced on three separate pairs of gels. MALDI-TOF identified 58 proteins with similar expression; 30 proteins were expressed twofold higher in HCEC from young donors; five proteins were expressed twofold higher in cells from older donors; and 10 proteins were identified in gels from young donors that did not match in gels from older donors. Several proteins expressed at higher levels in younger donors support metabolic activity, protect against oxidative damage, or mediate protein folding or degradation. Conclusions This is the first proteomic comparison of proteins expressed in HCEC cultured from young and older donors. Although restricted to proteins with isoelectric points between pH 4.0 and pH 7.0, the data obtained represent an initial step in the investigation of molecular mechanisms that underlie physiologically important age-related differences in cultured HCEC

  19. Development of anaerobically inducible nar promoter expression vectors for the expression of recombinant proteins in Escherichia coli.

    PubMed

    Kim, Nag-Jong; Choi, Jong Hyun; Kim, Yeon Chul; Lee, Jongwon; Lee, Sang Yup; Chang, Ho Nam; Lee, Pyung Cheon

    2011-01-10

    Dissolved oxygen (DO)-controlled nar promoter expression vectors were constructed, and their expression efficiency was compared with that of the T7 promoter pET22 expression vector by expressing human growth hormone (hGH), enhanced green fluorescence protein (EGFP), and β-tyrosinase in Escherichia coli cells. The nar promoter expression vector pRBS, which was engineered with a 5'-untranslated region and ribosomal binding site for the T7 promoter, expressed hGH at a rate of up to 32% of the total cellular proteins (TCP) in E. coli W3110narL⁻. The expression level of hGH was further enhanced, up to ~42% of the TCP, by adding the N-terminal peptide tag of β-galactosidase to hGH, which was comparable to the expression of ~43% of the TCP in pET-lac:hGH/BL21(DE3). A further engineered expression vector, pRBS(fnr), which coexpressed fumarate/nitrate reductase (fnr), expressed more EGFP than pET22 in BL21(DE3). In addition, recombinant β-tyrosinase was successfully expressed at a rate of up to ~45% of the TCP in pRBS(fnr) in W3110narL⁻. From these results, the DO-controlled nar promoter system developed in this study can be considered a reliable and cost-effective expression system for protein production, especially in large-scale fermentation, as an alternative to the pET/BL(DE3) system. PMID:21111764

  20. A mammalian germ cell-specific RNA-binding protein interacts with ubiquitously expressed proteins involved in splice site selection

    NASA Astrophysics Data System (ADS)

    Elliott, David J.; Bourgeois, Cyril F.; Klink, Albrecht; Stévenin, James; Cooke, Howard J.

    2000-05-01

    RNA-binding motif (RBM) genes are found on all mammalian Y chromosomes and are implicated in spermatogenesis. Within human germ cells, RBM protein shows a similar nuclear distribution to components of the pre-mRNA splicing machinery. To address the function of RBM, we have used protein-protein interaction assays to test for possible physical interactions between these proteins. We find that RBM protein directly interacts with members of the SR family of splicing factors and, in addition, strongly interacts with itself. We have mapped the protein domains responsible for mediating these interactions and expressed the mouse RBM interaction region as a bacterial fusion protein. This fusion protein can pull-down several functionally active SR protein species from cell extracts. Depletion and add-back experiments indicate that these SR proteins are the only splicing factors bound by RBM which are required for the splicing of a panel of pre-mRNAs. Our results suggest that RBM protein is an evolutionarily conserved mammalian splicing regulator which operates as a germ cell-specific cofactor for more ubiquitously expressed pre-mRNA splicing activators.

  1. Surface-layer protein from Caulobacter crescentus: expression, purification and X-ray crystallographic analysis.

    PubMed

    Jones, Michael D; Chan, Anson C K; Nomellini, John F; Murphy, Michael E P; Smit, John

    2016-09-01

    Protein surface layers are self-assembling, paracrystalline lattices on the surface of many prokaryotes. Surface-layer proteins have not benefited from widespread structural analysis owing to their resistance to crystallization. Here, the successful expression of a truncated version of RsaA, the surface-layer protein from Caulobacter crescentus, from a Caulobacter protein-expression system is reported. The purification, crystallization and initial X-ray diffraction analysis of the truncated RsaA, the largest surface-layer protein studied to date and the first from a Gram-negative bacterium, are also reported. PMID:27599857

  2. High-throughput Cloning and Expression of Integral Membrane Proteins in Escherichia coli

    PubMed Central

    Bruni, Renato

    2014-01-01

    Recently, several structural genomics centers have been established and a remarkable number of three-dimensional structures of soluble proteins have been solved. For membrane proteins, the number of structures solved has been significantly trailing those for their soluble counterparts, not least because over-expression and purification of membrane proteins is a much more arduous process. By using high throughput technologies, a large number of membrane protein targets can be screened simultaneously and a greater number of expression and purification conditions can be employed, leading to a higher probability of successfully determining the structure of membrane proteins. This unit describes the cloning, expression and screening of membrane proteins using high throughput methodologies developed in our laboratory. Basic Protocol 1 deals with the cloning of inserts into expression vectors by ligation-independent cloning. Basic Protocol 2 describes the expression and purification of the target proteins on a miniscale. Lastly, for the targets that express at the miniscale, basic protocols 3 and 4 outline the methods employed for the expression and purification of targets at the midi-scale, as well as a procedure for detergent screening and identification of detergent(s) in which the target protein is stable. PMID:24510647

  3. Dictyostelium discoideum--a promising expression system for the production of eukaryotic proteins.

    PubMed

    Arya, Ranjana; Bhattacharya, Alok; Saini, Kulvinder Singh

    2008-12-01

    In general, four different expression systems, namely, bacterial, yeast, baculovirus, and mammalian, are widely used for the overproduction of biochemical enzymes and therapeutic proteins. Clearly, bacterial expression systems offer ease of maneuverability with respect to large-scale production of recombinant proteins, while, a baculovirus expression system ensures proper protein modifications, processing, and refolding of complex proteins. Despite these advantages, mammalian cells remain the preferred host for many eukaryotic proteins of pharmaceutical importance, particularly, those requiring post-translational modifications. Recently, the single-celled slime mold, Dictyostelium discoideum (Dd), has emerged as a promising eukaryotic host for the expression of a variety of heterologous recombinant eukaryotic proteins. This organism possesses the complex cellular machinery required for orchestrating post-translational modifications similar to the one observed in higher eukaryotes. This review summarizes the advantages and disadvantages of Dictyostelium as an alternate system compared to other well-established expression systems. The key lessons learned from the expression of human recombinant proteins in this system are reviewed. Also, the strengths, weaknesses, and challenges associated with industrial-scale production of proteins in Dd expression system are discussed. PMID:18714070

  4. Promoter-cDNA-directed heterologous protein expression in Xenopus laevis oocytes.

    PubMed Central

    Swick, A G; Janicot, M; Cheneval-Kastelic, T; McLenithan, J C; Lane, M D

    1992-01-01

    Heterologous proteins can be expressed in Xenopus laevis oocytes by cytoplasmic microinjection of mRNA. To circumvent limitations inherent in this approach we investigate direct nuclear injection of strong viral expression vectors to drive transcription and subsequent translation of cDNAs encoding cytoplasmic, secreted, and plasma membrane proteins. After several viral promoters had been tested, the pMT2 vector was found to be a superior expression vector for X. laevis oocytes capable of directing expression of high levels of functional heterologous proteins. Typically the amount of protein derived from transcription-translation of the microinjected cDNA accounts for approximately 1% of total non-yolk protein. Moreover, the inefficiency usually associated with nuclear injections was overcome by coinjection of pMT2 driving expression of a secreted alkaline phosphatase as an internal control to select positive-expressing oocytes. Using this method, we have successfully expressed high levels of chloramphenicol acetyltransferase, the adipocyte-specific cytosolic 422(aP2) protein, and the membrane-associated glucose transporter GLUT1. The system described should be applicable to a wide variety of proteins for which cDNAs are available. Hence, the cumbersome and often inefficient in vitro synthesis of mRNA for studying ion channels, receptors, and transporters as well as for expression cloning in Xenopus oocytes should no longer be necessary. Images PMID:1542676

  5. DNA Microgels as a Platform for Cell-Free Protein Expression and Display.

    PubMed

    Kahn, Jason S; Ruiz, Roanna C H; Sureka, Swati; Peng, Songming; Derrien, Thomas L; An, Duo; Luo, Dan

    2016-06-13

    Protein expression and selection is an essential process in the modification of biological products. Expressed proteins are selected based on desired traits (phenotypes) from diverse gene libraries (genotypes), whose size may be limited due to the difficulties inherent in diverse cell preparation. In addition, not all genes can be expressed in cells, and linking genotype with phenotype further presents a great challenge in protein engineering. We present a DNA gel-based platform that demonstrates the versatility of two DNA microgel formats to address fundamental challenges of protein engineering, including high protein yield, isolation of gene sets, and protein display. We utilize microgels to show successful protein production and capture of a model protein, green fluorescent protein (GFP), which is further used to demonstrate a successful gene enrichment through fluorescence-activated cell sorting (FACS) of a mixed population of microgels containing the GFP gene. Through psoralen cross-linking of the hydrogels, we have synthesized DNA microgels capable of surviving denaturing conditions while still possessing the ability to produce protein. Lastly, we demonstrate a method of producing extremely high local gene concentrations of up to 32 000 gene repeats in hydrogels 1 to 2 μm in diameter. These DNA gels can serve as a novel cell-free platform for integrated protein expression and display, which can be applied toward more powerful, scalable protein engineering and cell-free synthetic biology with no physiological boundaries and limitations. PMID:27112709

  6. Enhanced expression of rabies virus surface G-protein in Escherichia coli using SUMO fusion.

    PubMed

    Singh, Ankit; Yadav, Dinesh; Rai, Krishan Mohan; Srivastava, Meenal; Verma, Praveen C; Singh, Pradhyumna K; Tuli, Rakesh

    2012-01-01

    Fusion systems are known to increase the expression of difficult to express recombinant proteins in soluble form to facilitate their purification. Rabies glycoprotein was also tough to express at sufficient level in soluble form in both E. coli and plant. The present work was aimed to over-express and purify this membrane protein from soluble extract of E. coli. Fusion of Small Ubiqutin like Modifier (SUMO) with rabies glycoprotein increased ~1.5 fold higher expression and ~3.0 fold solubility in comparison to non-fused in E. coli. The SUMO fusion also simplified the purification process. Previously engineered rabies glycoprotein gene in tobacco plants provides complete protection to mice, but the expression was very low for purification. Our finding demonstrated that the SUMO-fusion was useful for enhancing expression and solubility of the membrane protein and again proves to be a good alternative technology for applications in biomedical and pharmaceutical research. PMID:22134654

  7. INCREASED LIVER PATHOLOGY IN HEPATITIS C VIRUS TRANSGENIC MICE EXPRESSING THE HEPATITIS B VIRUS X PROTEIN

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Transgenic mice expressing the full-length HCV coding sequence were crossed with mice that express the HBV X gene-encoded regulatory protein HBx (ATX mice) to test the hypothesis that HBx expression accelerates HCV-induced liver pathogenesis. At 16 months (mo) of age, hepatocellular carcinoma was id...

  8. Selecting Optimum Eukaryotic Integral Membrane Proteins for Structure Determination by Rapid Expression and Solubilization Screening

    PubMed Central

    Li, Min; Hays, Franklin A.; Roe-Zurz, Zygy; Vuong, Linda; Kelly, Libusha; Ho, Chi-Min; Robbins, Renée M.; Pieper, Ursula; O’Connell, Joseph D.; Miercke, Larry J. W.; Giacomini, Kathleen M.; Sali, Andrej; Stroud, Robert M.

    2009-01-01

    A medium throughput approach is used to rapidly identify membrane proteins from a eukaryotic organism that are most amenable to expression in amounts and quality adequate to support structure determination. The goal was to expand knowledge of new membrane protein structures based on proteome-wide coverage. In the first phase membrane proteins from the budding yeast Saccharomyces cerevisiae were selected for homologous expression in S. cerevisiae, a system that can be adapted to expression of membrane proteins from other eukaryotes. We performed medium-scale expression and solubilization tests on 351 rationally selected membrane proteins from the budding yeast Saccharomyces cerevisiae. These targets are inclusive of all annotated and unannotated membrane protein families within the organism’s membrane proteome. 272 targets were expressed and of these 234 solubilized in the detergent n-dodecyl-β-D-maltopyranoside. Furthermore, we report the identity of a subset of targets that were purified to homogeneity to facilitate structure determinations. The extensibility of this approach is demonstrated with the expression of ten human integral membrane proteins from the solute carrier superfamily (SLC). This discovery-oriented pipeline provides an efficient way to select proteins from particular membrane protein classes, families, or organisms that may be more suited to structure analysis than others. PMID:19061901

  9. Construction of prokaryotic expression plasmid of mtrC protein of Neisseria gonorrhoeae and its expression in E. coli.

    PubMed

    Chen, Hongxiang; Tu, Yating; Lin, Nengxing; Huang, Changzheng

    2005-01-01

    In order to provide a rational research basis for detection of resistance of Neisseria gonorrhoeae to antimicrobial hydrophobic agents and study on the resistant mechanism of multiple transferable resistance (mtr) efflux system, plasmid pET-28a(+) encoding mtrC gene was constructed and the related target protein was expressed in Escherichia coli (E. coli) DE3. The fragments of mtrC gene of Neisseria gonorrhoeae from the standard strains were amplified and cloned into prokaryotic expression plasmid pET-28a(+) with restriction endonuclease to construct recombinant pET-mtrC which was verified by restriction endonuclease and DNA sequencing. The recombinant was transformed into E. coli DE3 to express the protein mtrC induced by IPTG. The results showed mtrC DNA fragment was proved correct through restriction endonuclease and DNA sequencing. Its sequence was 99.5% homologus to that published on GeneBank (U14993). A 48.5 kD fusion protein which was induced by IPTG was detected by SDS-PAGE. It was concluded that the construction of prokaryotic expression plasmid of mtrC protein of Neisseria gonorrhoeae was correct and the fusion protein was successively expressed in E. coli. PMID:16463681

  10. Proteomic analysis of differentially expressed proteins in Penaeus monodon hemocytes after Vibrio harveyi infection

    PubMed Central

    2010-01-01

    Background Viral and bacterial diseases can cause mass mortalities in commercial shrimp aquaculture. In contrast to studies on the antiviral response, the responses of shrimps to bacterial infections by high throughput techniques have been reported only at the transcriptional level and not at the translational level. In this study, a proteomic analysis of shrimp hemocytes to identify differentially expressed proteins in response to a luminous bacterium Vibrio harveyi was evaluated for its feasibility and is reported for the first time. Results The two-dimensional gel electrophoresis (2-DE) patterns of the hemocyte proteins from the unchallenged and V. harveyi challenged shrimp, Penaeus monodon, at 24 and 48 h post infection were compared. From this, 27 differentially expressed protein spots, and a further 12 weakly to non-differentially regulated control spots, were selected for further analyses by the LC-ESI-MS/MS. The 21 differentially expressed proteins that could be identified by homologous annotation were comprised of proteins that are directly involved in the host defense responses, such as hemocyanin, prophenoloxidase, serine proteinase-like protein, heat shock protein 90 and alpha-2-macroglobulin, and those involved in signal transduction, such as the14-3-3 protein epsilon and calmodulin. Western blot analysis confirmed the up-regulation of hemocyanin expression upon bacterial infection. The expression of the selected proteins which were the representatives of the down-regulated proteins (the 14-3-3 protein epsilon and alpha-2-macroglobulin) and of the up-regulated proteins (hemocyanin) was further assessed at the transcription level using real-time RT-PCR. Conclusions This work suggests the usefulness of a proteomic approach to the study of shrimp immunity and revealed hemocyte proteins whose expression were up regulated upon V. harveyi infection such as hemocyanin, arginine kinase and down regulated such as alpha-2-macroglobulin, calmodulin and 14

  11. Functional over-expression of the Stm1 protein, a G-protein-coupled receptor, in Schizosaccharomyces pombe.

    PubMed

    Chung, Kyung-Sook; Kim, Dong-Uk; Ryoo, Sung-Woo; Kang, Eun-Jung; Won, Misun; Kim, Lila; Jang, Young-Joo; Maeng, Pil-Jae; Kim, Sei-Chang; Yoo, Hyang-Sook; Hoe, Kwang-Lae

    2003-02-01

    We report here the first functional over-expression of the Stm1 protein, a G-protein-coupled receptor with seven-trans-membrane spanning regions, in a homologous expression system without internal modification of the open reading frame of Stm1. The entire coding sequence, except for the termination codon followed by a C-terminal His6 tag, has been cloned into the pREP1 vector. The functionally active Stm1-His6 was over-expressed in Schizosaccharomyces pombe under the control of the nmt1 (no message in thiamine) promoter. The expression after induction was 120 times as much as that of control before induction and it gave approximately 500 ng protein/2 x 10(7) cells. PMID:12882583

  12. Decreased expression of nucleophosmin/B23 increases drug sensitivity of adriamycin-resistant Molt-4 leukemia cells through mdr-1 regulation and Akt/mTOR signaling.

    PubMed

    Wang, Lingyan; Chen, Buyuan; Lin, Minhui; Cao, Yanqin; Chen, Yingyu; Chen, Xinji; Liu, Tingbo; Hu, Jianda

    2015-03-01

    Nucleophosmin/B23 (NPM) is a nuclear protein with prosurvival and ribosomal RNA processing functions. However, the potential role of NPM involved in drug-resistance in leukemia has not been investigated clearly. In this study, we generated an adriamycin (ADM)-resistant lymphoblastic cell line Molt-4/ADR (MAR) by stepwise induction. Cell proliferation, sensitivity to chemotherapy agents and expressions of drug resistance related molecules were assessed. The IC50 of Molt-4 cells were 0.58±0.11μmol/L and MAR cells were 22.56±1.94μmol/L, meaning MAR cells were 38.63 fold resistant to Molt-4 cells. Furthermore, MAR cells gained an expression of mdr-1 (P-gp) and a higher expression of NPM compared to Molt-4 cells. Knockdown of NPM by RNA interference (RNAi) suppressed the viability of both Molt-4 and MAR cells. After NPM RNAi, the IC50 of MAR and Molt-4 cells were 3.83±0.38μmol/L and 0.19±0.02μmol/L respectively. Both of them revealed an increase of drug sensitivity with down-regulation of mdr-1 and Akt/mTOR signaling. Knockdown of mdr-1 could also reverse the drug resistance, with no change in NPM expression. It could be concluded that knockdown of NPM reversed the drug resistance by down-regulating P-gp and Akt/mTOR signal pathway, indicating that NPM may serve as a potential modulator in drug resistance. PMID:25457413

  13. Store-Operated Ca2+ Channels in Mesangial Cells Inhibit Matrix Protein Expression.

    PubMed

    Wu, Peiwen; Wang, Yanxia; Davis, Mark E; Zuckerman, Jonathan E; Chaudhari, Sarika; Begg, Malcolm; Ma, Rong

    2015-11-01

    Accumulation of extracellular matrix derived from glomerular mesangial cells is an early feature of diabetic nephropathy. Ca(2+) signals mediated by store-operated Ca(2+) channels regulate protein production in a variety of cell types. The aim of this study was to determine the effect of store-operated Ca(2+) channels in mesangial cells on extracellular matrix protein expression. In cultured human mesangial cells, activation of store-operated Ca(2+) channels by thapsigargin significantly decreased fibronectin protein expression and collagen IV mRNA expression in a dose-dependent manner. Conversely, inhibition of the channels by 2-aminoethyl diphenylborinate significantly increased the expression of fibronectin and collagen IV. Similarly, overexpression of stromal interacting molecule 1 reduced, but knockdown of calcium release-activated calcium channel protein 1 (Orai1) increased fibronectin protein expression. Furthermore, 2-aminoethyl diphenylborinate significantly augmented angiotensin II-induced fibronectin protein expression, whereas thapsigargin abrogated high glucose- and TGF-β1-stimulated matrix protein expression. In vivo knockdown of Orai1 in mesangial cells of mice using a targeted nanoparticle siRNA delivery system resulted in increased expression of glomerular fibronectin and collagen IV, and mice showed significant mesangial expansion compared with controls. Similarly, in vivo knockdown of stromal interacting molecule 1 in mesangial cells by recombinant adeno-associated virus-encoded shRNA markedly increased collagen IV protein expression in renal cortex and caused mesangial expansion in rats. These results suggest that store-operated Ca(2+) channels in mesangial cells negatively regulate extracellular matrix protein expression in the kidney, which may serve as an endogenous renoprotective mechanism in diabetes. PMID:25788524

  14. Yeast PPR proteins, watchdogs of mitochondrial gene expression

    PubMed Central

    Herbert, Christopher J; Golik, Pawel; Bonnefoy, Nathalie

    2013-01-01

    PPR proteins are a family of ubiquitous RNA-binding factors, found in all the Eukaryotic lineages, and are particularly numerous in higher plants. According to recent bioinformatic analyses, yeast genomes encode from 10 (in S. pombe) to 15 (in S. cerevisiae) PPR proteins. All of these proteins are mitochondrial and very often interact with the mitochondrial membrane. Apart from the general factors, RNA polymerase and RNase P, most yeast PPR proteins are involved in the stability and/or translation of mitochondrially encoded RNAs. At present, some information concerning the target RNA(s) of most of these proteins is available, the next challenge will be to refine our understanding of the function of the proteins and to resolve the yeast PPR-RNA-binding code, which might differ significantly from the plant PPR code. PMID:24184848

  15. Purification of Human and Mammalian Membrane Proteins Expressed in Xenopus laevis Frog Oocytes for Structural Studies.

    PubMed

    Boggavarapu, Rajendra; Hirschi, Stephan; Harder, Daniel; Meury, Marcel; Ucurum, Zöhre; Bergeron, Marc J; Fotiadis, Dimitrios

    2016-01-01

    This protocol describes the isolation of recombinant human and mammalian membrane proteins expressed in Xenopus laevis frog oocytes for structural studies. The cDNA-derived cRNA of the desired genes is injected into several hundreds of oocytes, which are incubated for several days to allow protein expression. Recombinant proteins are then purified via affinity chromatography. The novelty of this method comes from the design of a plasmid that produces multi-tagged proteins and, most importantly, the development of a protocol for efficiently discarding lipids, phospholipids, and lipoproteins from the oocyte egg yolk, which represent the major contaminants in protein purifications. Thus, the high protein purity and good yield obtained from this method allows protein structure determination by transmission electron microscopy of single detergent-solubilized protein particles and of 2D crystals of membrane protein embedded in lipid bilayers. Additionally, a radiotracer assay for functional analysis of the expressed target proteins in oocytes is described. Overall, this method is a valuable option for structural studies of mammalian and particularly human proteins, for which other expression systems often fail. PMID:27485339

  16. Robust microarray production of freshly expressed proteins in a human milieu

    PubMed Central

    Festa, Fernanda; Rollins, Sean M.; Vattem, Krishna; Hathaway, Margarita; Lorenz, Phillip; Mendoza, Eliseo Alejandro; Yu, Xiaobo; Qiu, Ji; Kilmer, Greg; Jensen, Penny; Webb, Brian; Ryan, Ed T.; LaBaer, Joshua

    2013-01-01

    Purpose In vitro transcription/translation (IVTT) systems are widely used in proteomics. For clinical applications, mammalian systems are preferred for protein folding and activity; however, the level of protein obtained is low. A new system extracted from human cells (1-Step Human Coupled IVT) has the potential to overcome this problem and deliver high yields of protein expressed in a human milieu. Experimental design Western blots and self-assembled protein microarrays were used to test the efficiency of protein synthesis by 1-Step Human Coupled IVT (HCIVT) compared to rabbit reticulocyte lysate (RRL). The arrays were also used to measure the immune response obtained from serum of patients exposed to pathogens or vaccine. Results HCIVT performed better than RRL in all experiments. The yield of protein synthesized in HCIVT is more than 10 times higher than RRL, in both western blot and protein microarrays. Moreover, HCIVT showed a robust lot-to-lot reproducibility. In immune assays, the signals of many antigens were detected only in HCIVT-expressed arrays, mainly due to the reduction in the background signal and the increased levels of protein on the array. Conclusion and clinical relevance HCIVT is a robust IVTT system that yields high levels of protein produced in a human milieu. It can be used in applications where protein expression in a mammalian system and high yields are needed. The increased immunogenic response of HCIVT-expressed proteins will be critical for biomarker discovery in many diseases, including cancer. PMID:23027544

  17. Affinity Purification of a Recombinant Protein Expressed as a Fusion with the Maltose-Binding Protein (MBP) Tag

    PubMed Central

    Duong-Ly, Krisna C.; Gabelli, Sandra B.

    2015-01-01

    Expression of fusion proteins such as MBP fusions can be used as a way to improve the solubility of the expressed protein in E. coli (Fox and Waugh, 2003; Nallamsetty et al., 2005; Nallamsetty and Waugh, 2006) and as a way to introduce an affinity purification tag. The protocol that follows was designed by the authors as a first step in the purification of a recombinant protein fused with MBP, using fast protein liquid chromatography (FPLC). Cells should have been thawed, resuspended in binding buffer, and lysed by sonication or microfluidization before mixing with the amylose resin or loading on the column. Slight modifications to this protocol may be made to accommodate both the protein of interest and the availability of equipment. PMID:26096500

  18. High-throughput recombinant protein expression in Escherichia coli: current status and future perspectives

    PubMed Central

    2016-01-01

    The ease of genetic manipulation, low cost, rapid growth and number of previous studies have made Escherichia coli one of the most widely used microorganism species for producing recombinant proteins. In this post-genomic era, challenges remain to rapidly express and purify large numbers of proteins for academic and commercial purposes in a high-throughput manner. In this review, we describe several state-of-the-art approaches that are suitable for the cloning, expression and purification, conducted in parallel, of numerous molecules, and we discuss recent progress related to soluble protein expression, mRNA folding, fusion tags, post-translational modification and production of membrane proteins. Moreover, we address the ongoing efforts to overcome various challenges faced in protein expression in E. coli, which could lead to an improvement of the current system from trial and error to a predictable and rational design. PMID:27581654

  19. Proteomic Profiling Of Two-Dimensional Gel Electrophoresis Protein Expression Data

    NASA Astrophysics Data System (ADS)

    Ahmad, Norhaiza; Zhang, J.; Brown, P. J.; James, D. C.; Birch, J. R.; Racher, A. J.; Smales, C. M.

    2008-01-01

    We have undertaken two-dimensional gel electrophoresis (2-DE) proteomic profiling on a series of cell lines with different recombinant antibody production rates. Due to the nature of 2-DE proteomic investigations there will always be `process variability' factors in any data set collected in this way. Some of this variation will arise during sample preparation, gel running and staining, while further variation will arise from the gel analysis procedure. Therefore, in order to identify all significant changes in protein expression between biological samples when analysed by 2-DE, the system precision or `error', and how this correlates to protein abundance, must be known. Only then can the system be considered robust and investigators accurately and confidently report all observable statistically significant changes in protein expression. We introduce an expression variability test to identify protein spots whose expression correlates with increased antibody production. The results have highlighted a small number of candidate proteins for further investigation.

  20. A self-inducible heterologous protein expression system in Escherichia coli

    PubMed Central

    Briand, L.; Marcion, G.; Kriznik, A.; Heydel, J. M.; Artur, Y.; Garrido, C.; Seigneuric, R.; Neiers, F.

    2016-01-01

    Escherichia coli is an important experimental, medical and industrial cell factory for recombinant protein production. The inducible lac promoter is one of the most commonly used promoters for heterologous protein expression in E. coli. Isopropyl-β-D-thiogalactoside (IPTG) is currently the most efficient molecular inducer for regulating this promoter’s transcriptional activity. However, limitations have been observed in large-scale and microplate production, including toxicity, cost and culture monitoring. Here, we report the novel SILEX (Self-InducibLe Expression) system, which is a convenient, cost-effective alternative that does not require cell density monitoring or IPTG induction. We demonstrate the broad utility of the presented self-inducible method for a panel of diverse proteins produced in large amounts. The SILEX system is compatible with all classical culture media and growth temperatures and allows protein expression modulation. Importantly, the SILEX system is proven to be efficient for protein expression screening on a microplate scale. PMID:27611846

  1. Selective Methyl Labeling of Eukaryotic Membrane Proteins Using Cell-Free Expression

    PubMed Central

    2015-01-01

    Structural characterization of membrane proteins and other large proteins with NMR relies increasingly on perdeuteration combined with incorporation of specifically protonated amino acid moieties, such as methyl groups of isoleucines, valines, or leucines. The resulting proton dilution reduces dipolar broadening producing sharper resonance lines, ameliorates spectral crowding, and enables measuring of crucial distances between and to methyl groups. While incorporation of specific methyl labeling is now well established for bacterial expression using suitable precursors, corresponding methods are still lacking for cell-free expression, which is often the only choice for producing labeled eukaryotic membrane proteins in mg quantities. Here we show that we can express methyl-labeled human integral membrane proteins cost-effectively by cell-free expression based of crude hydrolyzed ILV-labeled OmpX inclusion bodies. These are obtained in Escherichia coli with very high quantity and represent an optimal intermediate to channel ILV precursors into the eukaryotic proteins. PMID:24937763

  2. High-throughput recombinant protein expression in Escherichia coli: current status and future perspectives.

    PubMed

    Jia, Baolei; Jeon, Che Ok

    2016-08-01

    The ease of genetic manipulation, low cost, rapid growth and number of previous studies have made Escherichia coli one of the most widely used microorganism species for producing recombinant proteins. In this post-genomic era, challenges remain to rapidly express and purify large numbers of proteins for academic and commercial purposes in a high-throughput manner. In this review, we describe several state-of-the-art approaches that are suitable for the cloning, expression and purification, conducted in parallel, of numerous molecules, and we discuss recent progress related to soluble protein expression, mRNA folding, fusion tags, post-translational modification and production of membrane proteins. Moreover, we address the ongoing efforts to overcome various challenges faced in protein expression in E. coli, which could lead to an improvement of the current system from trial and error to a predictable and rational design. PMID:27581654

  3. Selective methyl labeling of eukaryotic membrane proteins using cell-free expression.

    PubMed

    Linser, Rasmus; Gelev, Vladimir; Hagn, Franz; Arthanari, Haribabu; Hyberts, Sven G; Wagner, Gerhard

    2014-08-13

    Structural characterization of membrane proteins and other large proteins with NMR relies increasingly on perdeuteration combined with incorporation of specifically protonated amino acid moieties, such as methyl groups of isoleucines, valines, or leucines. The resulting proton dilution reduces dipolar broadening producing sharper resonance lines, ameliorates spectral crowding, and enables measuring of crucial distances between and to methyl groups. While incorporation of specific methyl labeling is now well established for bacterial expression using suitable precursors, corresponding methods are still lacking for cell-free expression, which is often the only choice for producing labeled eukaryotic membrane proteins in mg quantities. Here we show that we can express methyl-labeled human integral membrane proteins cost-effectively by cell-free expression based of crude hydrolyzed ILV-labeled OmpX inclusion bodies. These are obtained in Escherichia coli with very high quantity and represent an optimal intermediate to channel ILV precursors into the eukaryotic proteins. PMID:24937763

  4. A self-inducible heterologous protein expression system in Escherichia coli.

    PubMed

    Briand, L; Marcion, G; Kriznik, A; Heydel, J M; Artur, Y; Garrido, C; Seigneuric, R; Neiers, F

    2016-01-01

    Escherichia coli is an important experimental, medical and industrial cell factory for recombinant protein production. The inducible lac promoter is one of the most commonly used promoters for heterologous protein expression in E. coli. Isopropyl-β-D-thiogalactoside (IPTG) is currently the most efficient molecular inducer for regulating this promoter's transcriptional activity. However, limitations have been observed in large-scale and microplate production, including toxicity, cost and culture monitoring. Here, we report the novel SILEX (Self-InducibLe Expression) system, which is a convenient, cost-effective alternative that does not require cell density monitoring or IPTG induction. We demonstrate the broad utility of the presented self-inducible method for a panel of diverse proteins produced in large amounts. The SILEX system is compatible with all classical culture media and growth temperatures and allows protein expression modulation. Importantly, the SILEX system is proven to be efficient for protein expression screening on a microplate scale. PMID:27611846

  5. A Link Between Integral Membrane Protein Expression and Simulated Integration Efficiency

    PubMed Central

    Müller, Axel; Tiemann, Katrin; Saladi, Shyam M.; Galimidi, Rachel P.; Zhang, Bin; Clemons, William M.; Miller, Thomas F.

    2016-01-01

    Integral membrane proteins (IMP) control the flow of information and nutrients across cell membranes, yet IMP mechanistic studies are hindered by difficulties in expression. We investigate this issue by addressing the connection between IMP sequence and observed expression levels. For homologs of the IMP TatC, observed expression levels widely vary and are affected by small changes in protein sequence. The effect of sequence changes on experimentally observed expression levels strongly correlates with the simulated integration efficiency obtained from coarse-grained modeling, which is directly confirmed using an in vivo assay. Furthermore, mutations that improve the simulated integration efficiency likewise increase the experimentally observed expression levels. Demonstration of these trends in both Escherichia coli and Mycobacterium smegmatis suggests that the results are general to other expression systems. This work suggests that IMP integration is a determinant for successful expression, raising the possibility of controlling IMP expression via rational design. PMID:27524616

  6. A Link between Integral Membrane Protein Expression and Simulated Integration Efficiency.

    PubMed

    Marshall, Stephen S; Niesen, Michiel J M; Müller, Axel; Tiemann, Katrin; Saladi, Shyam M; Galimidi, Rachel P; Zhang, Bin; Clemons, William M; Miller, Thomas F

    2016-08-23

    Integral membrane proteins (IMPs) control the flow of information and nutrients across cell membranes, yet IMP mechanistic studies are hindered by difficulties in expression. We investigate this issue by addressing the connection between IMP sequence and observed expression levels. For homologs of the IMP TatC, observed expression levels vary widely and are affected by small changes in protein sequence. The effect of sequence changes on experimentally observed expression levels strongly correlates with the simulated integration efficiency obtained from coarse-grained modeling, which is directly confirmed using an in vivo assay. Furthermore, mutations that improve the simulated integration efficiency likewise increase the experimentally observed expression levels. Demonstration of these trends in both Escherichia coli and Mycobacterium smegmatis suggests that the results are general to other expression systems. This work suggests that IMP integration is a determinant for successful expression, raising the possibility of controlling IMP expression via rational design. PMID:27524616

  7. In-Vivo Real-Time Control of Protein Expression from Endogenous and Synthetic Gene Networks

    PubMed Central

    Orabona, Emanuele; De Stefano, Luca; Ferry, Mike; Hasty, Jeff; di Bernardo, Mario; di Bernardo, Diego

    2014-01-01

    We describe an innovative experimental and computational approach to control the expression of a protein in a population of yeast cells. We designed a simple control algorithm to automatically regulate the administration of inducer molecules to the cells by comparing the actual protein expression level in the cell population with the desired expression level. We then built an automated platform based on a microfluidic device, a time-lapse microscopy apparatus, and a set of motorized syringes, all controlled by a computer. We tested the platform to force yeast cells to express a desired fixed, or time-varying, amount of a reporter protein over thousands of minutes. The computer automatically switched the type of sugar administered to the cells, its concentration and its duration, according to the control algorithm. Our approach can be used to control expression of any protein, fused to a fluorescent reporter, provided that an external molecule known to (indirectly) affect its promoter activity is available. PMID:24831205

  8. Protein expression profiles of intestinal epithelial co-cultures: effect of functionalised carbon nanotube exposure

    PubMed Central

    Lai, Xianyin; Blazer-Yost, Bonnie L.; Clack, James W.; Fears, Sharry L.; Mitra, Somenath; Ntim, Susana Addo; Ringham, Heather N.

    2013-01-01

    To assess the biological effects of low level, water dispersible, functionalised carbon nanotube (f-CNT) exposure in an in vitro model simulating the digestive tract, cellular protein expression was quantified and compared using label-free quantitative mass spectrometry (LFQMS). Co-cultured cells were exposed to well-characterised SWCNT-COOH, MWCNT-COOH, and MWCNT-PVP. The relative expression of 2,282 unique proteins was compared across the dose groups. 428 proteins were found to be differentially expressed. At the high dose, the extent of differential protein expression was CNT-specific and directly related to CNT colloidal stability. Cells responded to low level MWCNT-PVP exposure with three-fold greater differential expression. Bioinformatic analysis indicated significant and f-CNT-specific effects on relevant molecular and cellular functions and canonical pathways, with little overlap across f-CNT type and in the absence of overt toxicity. PMID:24228069

  9. In-vivo real-time control of protein expression from endogenous and synthetic gene networks.

    PubMed

    Menolascina, Filippo; Fiore, Gianfranco; Orabona, Emanuele; De Stefano, Luca; Ferry, Mike; Hasty, Jeff; di Bernardo, Mario; di Bernardo, Diego

    2014-05-01

    We describe an innovative experimental and computational approach to control the expression of a protein in a population of yeast cells. We designed a simple control algorithm to automatically regulate the administration of inducer molecules to the cells by comparing the actual protein expression level in the cell population with the desired expression level. We then built an automated platform based on a microfluidic device, a time-lapse microscopy apparatus, and a set of motorized syringes, all controlled by a computer. We tested the platform to force yeast cells to express a desired fixed, or time-varying, amount of a reporter protein over thousands of minutes. The computer automatically switched the type of sugar administered to the cells, its concentration and its duration, according to the control algorithm. Our approach can be used to control expression of any protein, fused to a fluorescent reporter, provided that an external molecule known to (indirectly) affect its promoter activity is available. PMID:24831205

  10. Contaminant loading in remote Arctic lakes affects cellular stress-related proteins expression in feral charr.

    USGS Publications Warehouse

    Wiseman, Steve; Jorgensen, Even H.; Maule, Alec G.; Vijayan, Mathilakath M.

    2011-01-01

    The remote Arctic lakes on Bjornoya Island, Norway, offer a unique opportunity to study possible affect of lifelong contaminant exposure in wild populations of landlocked Arctic charr (Salvelinus alpinus). This is because Lake Ellasjoen has persistent organic pollutant (POP) levels that are significantly greater than in the nearby Lake Oyangen. We examined whether this differential contaminant loading was reflected in the expression of protein markers of exposure and effect in the native fish. We assessed the expressions of cellular stress markers, including cytochrome P4501A (Cyp1A), heat shock protein 70 (hsp70), and glucocorticoid receptor (GR) in feral charr from the two lakes. The average polychlorinated biphenyl (PCB) load in the charr liver from Ellasjoen was approximately 25-fold higher than in individuals from Oyangen. Liver Cyp1A protein expression was significantly higher in individuals from Ellasjoen compared with Oyangen, confirming differential PCB exposure. There was no significant difference in hsp70 protein expression in charr liver between the two lakes. However, brain hsp70 protein expression was significantly elevated in charr from Ellasjoen compared with Oyangen. Also, liver GR protein expression was significantly higher in the Ellasjoen charr compared with Oyangen charr. Taken together, our results suggest changes to cellular stress-related protein expression as a possible adaptation to chronic-contaminant exposure in feral charr in the Norwegian high-Arctic.

  11. Gastrointestinal stromal tumors regularly express synaptic vesicle proteins: evidence of a neuroendocrine phenotype.

    PubMed

    Bümming, Per; Nilsson, Ola; Ahlman, Håkan; Welbencer, Anna; Andersson, Mattias K; Sjölund, Katarina; Nilsson, Bengt

    2007-09-01

    Gastrointestinal stromal tumors (GISTs) are thought to originate from the interstitial cells of Cajal, which share many properties with neurons of the gastrointestinal tract. Recently, we demonstrated expression of the hormone ghrelin in GIST. The aim of the present study was therefore to evaluate a possible neuroendocrine phenotype of GIST. Specimens from 41 GISTs were examined for the expression of 12 different synaptic vesicle proteins. Expression of synaptic-like microvesicle proteins, e.g., Synaptic vesicle protein 2 (SV2), synaptobrevin, synapsin 1, and amphiphysin was demonstrated in a majority of GISTs by immunohistochemistry, western blotting, and quantitative reversetranscriptase PCR. One-third of the tumors also expressed the large dense core vesicle protein vesicular monoamine transporter 1. Presence of microvesicles and dense core vesicles in GIST was confirmed by electron microscopy. The expression of synaptic-like microvesicle proteins in GIST was not related to risk profile or to KIT/platelet derived growth factor alpha (PDGFRA) mutational status. Thus, GISTs regularly express a subset of synaptic-like microvesicle proteins necessary for the regulated secretion of neurotransmitters and hormones. Expression of synaptic-like micro-vesicle proteins, ghrelin and peptide hormone receptors in GIST indicate a neuroendocrine phenotype and suggest novel possibilities to treat therapy-resistant GIST. PMID:17914114

  12. Cross-tissue Analysis of Gene and Protein Expression in Normal and Cancer Tissues

    PubMed Central

    Kosti, Idit; Jain, Nishant; Aran, Dvir; Butte, Atul J.; Sirota, Marina

    2016-01-01

    The central dogma of molecular biology describes the translation of genetic information from mRNA to protein, but does not specify the quantitation or timing of this process across the genome. We have analyzed protein and gene expression in a diverse set of human tissues. To study concordance and discordance of gene and protein expression, we integrated mass spectrometry data from the Human Proteome Map project and RNA-Seq measurements from the Genotype-Tissue Expression project. We analyzed 16,561 genes and the corresponding proteins in 14 tissue types across nearly 200 samples. A comprehensive tissue- and gene-specific analysis revealed that across the 14 tissues, correlation between mRNA and protein expression was positive and ranged from 0.36 to 0.5. We also identified 1,012 genes whose RNA and protein expression was correlated across all the tissues and examined genes and proteins that were concordantly and discordantly expressed for each tissue of interest. We extended our analysis to look for genes and proteins that were differentially correlated in cancer compared to normal tissues, showing higher levels of correlation in normal tissues. Finally, we explored the implications of these findings in the context of biomarker and drug target discovery. PMID:27142790

  13. Cross-tissue Analysis of Gene and Protein Expression in Normal and Cancer Tissues.

    PubMed

    Kosti, Idit; Jain, Nishant; Aran, Dvir; Butte, Atul J; Sirota, Marina

    2016-01-01

    The central dogma of molecular biology describes the translation of genetic information from mRNA to protein, but does not specify the quantitation or timing of this process across the genome. We have analyzed protein and gene expression in a diverse set of human tissues. To study concordance and discordance of gene and protein expression, we integrated mass spectrometry data from the Human Proteome Map project and RNA-Seq measurements from the Genotype-Tissue Expression project. We analyzed 16,561 genes and the corresponding proteins in 14 tissue types across nearly 200 samples. A comprehensive tissue- and gene-specific analysis revealed that across the 14 tissues, correlation between mRNA and protein expression was positive and ranged from 0.36 to 0.5. We also identified 1,012 genes whose RNA and protein expression was correlated across all the tissues and examined genes and proteins that were concordantly and discordantly expressed for each tissue of interest. We extended our analysis to look for genes and proteins that were differentially correlated in cancer compared to normal tissues, showing higher levels of correlation in normal tissues. Finally, we explored the implications of these findings in the context of biomarker and drug target discovery. PMID:27142790

  14. Rhythmic expression of DEC2 protein in vitro and in vivo

    PubMed Central

    SATO, FUYUKI; MURAGAKI, YASUTERU; KAWAMOTO, TAKESHI; FUJIMOTO, KATSUMI; KATO, YUKIO; ZHANG, YANPING

    2016-01-01

    Basic helix-loop-helix (bHLH) transcription factor DEC2 (bHLHE41/Sharp1) is one of the clock genes that show a circadian rhythm in various tissues. DEC2 regulates differentiation, sleep length, tumor cell invasion and apoptosis. Although studies have been conducted on the rhythmic expression of DEC2 mRNA in various tissues, the precise molecular mechanism of DEC2 expression is poorly understood. In the present study, we examined whether DEC2 protein had a rhythmic expression. Western blot analysis for DEC2 protein revealed a rhythmic expression in mouse liver, lung and muscle and in MCF-7 and U2OS cells. In addition, AMP-activated protein kinase (AMPK) activity (phosphorylation of AMPK) in mouse embryonic fibroblasts (MEFs) exhibited a rhythmic expression under the condition of medium change or glucose-depleted medium. However, the rhythmic expression of DEC2 in MEF gradually decreased in time under these conditions. The medium change affected the levels of DEC2 protein and phosphorylation of AMPK. In addition, the levels of DEC2 protein showed a rhythmic expression in vivo and in MCF-7 and U2OS cells. The results showed that the phosphorylation of AMPK immunoreactivity was strongly detected in the liver and lung of DEC2 knockout mice compared with that of wild-type mice. These results may provide new insights into rhythmic expression and the regulation between DEC2 protein and AMPK activity. PMID:27284410

  15. Proteins expressed in blue-green sharpshooter leafhoppers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We used a metagenomics approach to identify proteins from the blue-green sharpshooter, Graphocephala atropunctata (Hemiptera: Cicadellidae) which is an important vector of Pierce’s disease of grapes. The 44 proteins are being used as markers to monitor and identify current and exotic introductions o...

  16. Utility of proteomics techniques for assessing protein expression

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In recent years, proteomic technologies have been frequently used as an effective analytical tool for examining modifications of protein profiles for accessing the bio-safety of genetically modified crops (GMO). Understanding of natural variation of soybean seed proteins is critical for determining...

  17. Utility of proteomics techniques for assessing protein expression

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Proteomic technologies are currently used as an effective analytical tool for examining modifications in protein profiles for assessing the bio-safety of genetically modified (GM) crop organisms. Understanding the natural variation of soybean seed proteins is necessary to evaluate potential uninten...

  18. miR-24 and miR-205 expression is dependent on HPV onco-protein expression in keratinocytes

    SciTech Connect

    McKenna, Declan J.; Patel, Daksha; McCance, Dennis J.

    2014-01-05

    A screen of microRNA (miRNA) expression following differentiation in human foreskin keratinocytes (HFKs) identified changes in several miRNAs, including miR-24 and miR-205. We investigated how expression of Human Papilloma Virus Type-16 (HPV16) onco-proteins E6 and E7 affected expression of miR-24 and miR-205 during proliferation and differentiation of HFKs. We show that the induction of both miR-24 and miR-205 observed during differentiation of HFKs is lost in HFKs expressing E6 and E7. We demonstrate that the effect on miR-205 is due to E7 activity, as miR-205 expression is dependent on pRb expression. Finally, we provide evidence that miR-24 effects in the cell may be due to targeting of cyclin dependent kinase inhibitor p27. In summary, these results indicate that expression of both miR-24 and miR-205 are impacted by E6 and/or E7 expression, which may be one mechanism by which HPV onco-proteins can disrupt the balance between proliferation and differentiation in keratinocytes. - Highlights: • miR-24 and miR-205 are induced during keratinocyte differentiation. • This induction is lost in keratinocytes expressing HPV onco-proteins E6 and E7. • miR-205 is dependent upon pRb expression. • miR-24 targets p27 in cycling keratinocytes.

  19. Evolutionary Divergence of Gene and Protein Expression in the Brains of Humans and Chimpanzees

    PubMed Central

    Bauernfeind, Amy L.; Soderblom, Erik J.; Turner, Meredith E.; Moseley, M. Arthur; Ely, John J.; Hof, Patrick R.; Sherwood, Chet C.; Wray, Gregory A.; Babbitt, Courtney C.

    2015-01-01

    Although transcriptomic profiling has become the standard approach for exploring molecular differences in the primate brain, very little is known about how the expression levels of gene transcripts relate to downstream protein abundance. Moreover, it is unknown whether the relationship changes depending on the brain region or species under investigation. We performed high-throughput transcriptomic (RNA-Seq) and proteomic (liquid chromatography coupled with tandem mass spectrometry) analyses on two regions of the human and chimpanzee brain: The anterior cingulate cortex and caudate nucleus. In both brain regions, we found a lower correlation between mRNA and protein expression levels in humans and chimpanzees than has been reported for other tissues and cell types, suggesting that the brain may engage extensive tissue-specific regulation affecting protein abundance. In both species, only a few categories of biological function exhibited strong correlations between mRNA and protein expression levels. These categories included oxidative metabolism and protein synthesis and modification, indicating that the expression levels of mRNA transcripts supporting these biological functions are more predictive of protein expression compared with other functional categories. More generally, however, the two measures of molecular expression provided strikingly divergent perspectives into differential expression between human and chimpanzee brains: mRNA comparisons revealed significant differences in neuronal communication, ion transport, and regulatory processes, whereas protein comparisons indicated differences in perception and cognition, metabolic processes, and organization of the cytoskeleton. Our results highlight the importance of examining protein expression in evolutionary analyses and call for a more thorough understanding of tissue-specific protein expression levels. PMID:26163674

  20. PepGMV Rep-Protein Expression in Mammalian Cells

    PubMed Central

    Chapa-Oliver, Angela María; Mejía-Teniente, Laura; García-Gasca, Teresa; Guevara-Gonzalez, Ramon Gerardo; Torres-Pacheco, Irineo

    2012-01-01

    The Geminiviruses genome is a small, single strand DNA that replicates in the plant cell nucleus. Analogous to animal DNA viruses, Geminiviruses depend on the host replication machinery to amplify their genomes and only supply the factors required to initiate their replication. Consequently, Geminiviruses remove the cell-cycle arrest and induce the host replication machinery using an endocycle process. They encode proteins, such as the conserved replication-associated proteins (Rep) that interact with retinoblastoma-like proteins in plants and alter the cell division cycle in yeasts. Therefore, the aim of this work is to analyze the impact of Pepper Golden Mosaic Virus (PepGMV) Rep protein in mammalian cells. Results indicate that the pTracer-SV40:Rep construction obtained in this work can be used to analyze the Rep protein effect in mammalian cells in order to compare the cell cycle regulation mechanisms in plants and animals. PMID:23170183

  1. Expression of Epitope-Tagged Proteins in Mammalian Cells in Culture.

    PubMed

    Bhatt, Jay M; Styers, Melanie L; Sztul, Elizabeth

    2016-01-01

    Before the advent of molecular methods to tag proteins, visualization of proteins within cells required the use of antibodies directed against the protein of interest. Thus, only proteins for which antibodies were available could be visualized. Epitope tagging allows the detection of all proteins with existing sequence information, irrespective of the availability of antibodies directed against them. This technique involves the generation of DNA constructs that express the protein of interest tagged with an epitope that can be recognized by a commercially available antibody. Proteins can be tagged with a wide variety of epitopes using commercially available vectors that allow expression in mammalian cells. Epitope-tagged proteins are easily transfected into mammalian cell lines and, in most cases, tightly mimic the behavior of the endogenous protein. Tagged proteins exogenously expressed in cells provide different types of information depending on the subsequent detection approaches. Using immunofluorescence and immunoelectron microscopy with anti-tag antibodies, relative to known markers of cellular organelles, can provide information on the subcellular localization of the tagged protein and may provide clues regarding the protein's function. Immunofluorescence with anti-tag antibodies can also be utilized to assess the tagged protein's responses to cellular signals and pharmacological treatments. Immunoprecipitations with anti-tag antibodies can recover protein complexes containing the protein of interest, resulting in the identification of interacting proteins. Recovery of tagged proteins on affinity matrices allows their purification for use in biochemical assays. In addition, specialized fluorescent tags, such as the green fluorescent protein (GFP) allow the analysis of cellular dynamics in live cells in real time. PMID:27515071

  2. Dynamic Stabilization of Expressed Proteins in Engineered Diatom Biosilica Matrices.

    PubMed

    Xiong, Yijia; Ford, Nicole R; Hecht, Karen A; Roesijadi, Guritno; Squier, Thomas C

    2016-05-18

    Self-assembly of recombinant proteins within the biosilica of living diatoms represents a means to construct functional materials in a reproducible and scalable manner that will enable applications that harness the inherent specificities of proteins to sense and respond to environmental cues. Here we describe the use of a silaffin-derived lysine-rich 39-amino-acid targeting sequence (Sil3T8) that directs a single chain fragment variable (scFv) antibody or an enhanced green fluorescent protein (EGFP) to assemble within the biosilica frustule, resulting in abundance of >200 000 proteins per frustule. Using either a fluorescent ligand bound to the scFv or the intrinsic fluorescence of EGFP, we monitored protein conformational dynamics, accessibility to external quenchers, binding affinity, and conformational stability. Like proteins in solution, proteins within isolated frustules undergo isotropic rotational motion, but with 2-fold increases in rotational correlation times that are indicative of weak macromolecular associations within the biosilica. Solvent accessibilities and high-affinity (pM) binding are comparable to those in solution. In contrast to solution conditions, scFv antibodies within the biosilica matrix retain their binding affinity in the presence of chaotropic agents (i.e., 8 M urea). Together, these results argue that dramatic increases in protein conformational stability within the biosilica matrices arise through molecular crowding, acting to retain native protein folds and associated functionality with the potential to allow the utility of engineered proteins under a range of harsh environmental conditions associated with environmental sensing and industrial catalytic transformations. PMID:27139003

  3. Expression of two membrane fusion proteins, synaptosome-associated protein of 25 kDa and vesicle-associated membrane protein, in choroid plexus epithelium.

    PubMed

    Chung, I; Burkart, A; Szmydynger-Chodobska, J; Dodd, K A; Trimble, W S; Miller, K V; Shim, M; Chodobski, A

    2003-01-01

    In addition to being the major site of cerebrospinal fluid formation, the choroid plexus epithelium emerges as an important source of polypeptides in the brain. Physiologically regulated release of some polypeptides synthesized by the choroid plexus has been shown. The molecular mechanisms underlying this polypeptide secretion have not been characterized, however. In the present study, synaptosome-associated protein of 25 kDa and vesicle-associated membrane protein, two membrane fusion proteins playing a critical role in exocytosis in neurons and endocrine cells, were found to be expressed in the choroid plexus epithelium. It was also shown that in choroidal epithelium, synaptosome-associated protein of 25 kDa and vesicle-associated membrane protein stably interact. Two members of the vesicle-associated membrane protein family, vesicle-associated membrane protein-1 and vesicle-associated membrane protein-2, were expressed in the rat choroid plexus at the messenger RNA and protein level. However, their newly discovered isoforms, vesicle-associated membrane protein-1b and vesicle-associated membrane protein-2b, produced by alternative RNA splicing, were not detected in choroidal tissue. Immunohistochemistry demonstrated that vesicle-associated membrane protein is confined to the cytoplasm of choroidal epithelium, whereas synaptosome-associated protein of 25 kDa is associated with plasma membranes, albeit with a varied cellular distribution among species studied. Specifically, in the rat choroid plexus, synaptosome-associated protein of 25 kDa was localized to the basolateral membrane domain of choroidal epithelium and was expressed in small groups of cells. In comparison, in ovine and human choroidal tissues, apical staining for synaptosome-associated protein of 25 kDa was found in the majority of epithelial cells. These species-related differences in cellular synaptosome-associated protein of 25 kDa distribution suggested that the synaptosome-associated protein of

  4. Pan-Cancer Analysis for Studying Cancer Stage using Protein Expression Data

    PubMed Central

    Mishra, Sameer; Kaddi, Chanchala D.; Wang, May D.

    2016-01-01

    Pan-cancer analyses attempt to discover similar features among multiple cancers in order to identify fundamental patterns common to cancer development and progression. Pan-cancer analysis at the level of protein expression is particularly important because protein expression is more immediately related to patient phenotype than genomic or transcriptomic data. This study aims to analyze differentially expressed (DE) proteins between early and advanced cases of multiple cancer types through the usage of reverse-phase protein array data. The relevance of these proteins is further investigated by developing predictive models using K-nearest neighbor and linear discriminant analysis classifiers. The results of this study suggest that a pan-cancer analysis may be highly complementary to standard analysis of an individual cancer for identifying biologically relevant DE proteins, and can assist in developing effective predictive models for cancer progression. PMID:26738195

  5. Murine cerebellar neurons express a novel gene encoding a protein related to cell cycle control and cell fate determination proteins.

    PubMed

    Taoka, M; Isobe, T; Okuyama, T; Watanabe, M; Kondo, H; Yamakawa, Y; Ozawa, F; Hishinuma, F; Kubota, M; Minegishi, A

    1994-04-01

    We cloned cDNAs of a novel protein (designated V-1) that has been identified from among the developmentally regulated proteins in the rat cerebellum. Protein sequencing analysis (Taoka, M., Yamakuni, T., Song, S.-Y., Yamakawa, Y., Seta, K., Okuyama, T., and Isobe, T. (1992) Eur. J. Biochem. 207, 615-620) and cDNA sequence analysis revealed that the V-1 protein consists of 117 amino acids and contains 2.5 contiguous repeats of the cdc10/SWI6 motif, which was originally found in the products of the cell cycle control genes of yeasts and the cell fate determination genes in Drosophila and Caenorhabditis elegans. In situ hybridization histochemistry revealed that the expression of the V-1 gene is transiently increased in postmigratory granule cells during postnatal rat cerebellar development and thereafter is markedly suppressed, whereas Purkinje cells constitutively express V-1 mRNA. In contrast, cerebellar granule cells of the staggerer mutant mouse continue to express the V-1 gene even when the granule cells of the normal mouse have ceased to express the V-1 gene, suggesting that the expression of the V-1 gene in granule cells is regulated through the interaction with Purkinje cells. On the basis of these results, we postulate that the V-1 protein has a potential role in the differentiation of granule cells. PMID:8144589

  6. Expression Atlas update—an integrated database of gene and protein expression in humans, animals and plants

    PubMed Central

    Petryszak, Robert; Keays, Maria; Tang, Y. Amy; Fonseca, Nuno A.; Barrera, Elisabet; Burdett, Tony; Füllgrabe, Anja; Fuentes, Alfonso Muñoz-Pomer; Jupp, Simon; Koskinen, Satu; Mannion, Oliver; Huerta, Laura; Megy, Karine; Snow, Catherine; Williams, Eleanor; Barzine, Mitra; Hastings, Emma; Weisser, Hendrik; Wright, James; Jaiswal, Pankaj; Huber, Wolfgang; Choudhary, Jyoti; Parkinson, Helen E.; Brazma, Alvis

    2016-01-01

    Expression Atlas (http://www.ebi.ac.uk/gxa) provides information about gene and protein expression in animal and plant samples of different cell types, organism parts, developmental stages, diseases and other conditions. It consists of selected microarray and RNA-sequencing studies from ArrayExpress, which have been manually curated, annotated with ontology terms, checked for high quality and processed using standardised analysis methods. Since the last update, Atlas has grown seven-fold (1572 studies as of August 2015), and incorporates baseline expression profiles of tissues from Human Protein Atlas, GTEx and FANTOM5, and of cancer cell lines from ENCODE, CCLE and Genentech projects. Plant studies constitute a quarter of Atlas data. For genes of interest, the user can view baseline expression in tissues, and differential expression for biologically meaningful pairwise comparisons—estimated using consistent methodology across all of Atlas. Our first proteomics study in human tissues is now displayed alongside transcriptomics data in the same tissues. Novel analyses and visualisations include: ‘enrichment’ in each differential comparison of GO terms, Reactome, Plant Reactome pathways and InterPro domains; hierarchical clustering (by baseline expression) of most variable genes and experimental conditions; and, for a given gene-condition, distribution of baseline expression across biological replicates. PMID:26481351

  7. Differentiation inducing factor-1 (DIF-1) induces gene and protein expression of the Dictyostelium nuclear calmodulin-binding protein nucleomorphin.

    PubMed

    O'Day, Danton H; Poloz, Yekaterina; Myre, Michael A

    2009-02-01

    The nucleomorphin gene numA1 from Dictyostelium codes for a multi-domain, calmodulin binding protein that regulates nuclear number. To gain insight into the regulation of numA, we assessed the effects of the stalk cell differentiation inducing factor-1 (DIF-1), an extracellular signalling molecule, on the expression of numA1 RNA and protein. For comparison, the extracellular signalling molecules cAMP (mediates chemotaxis, prestalk and prespore differentiation) and ammonia (NH(3)/NH(4)(+); antagonizes DIF) were also studied. Starvation, which is a signal for multicellular development, results in a greater than 80% decrease in numA1 mRNA expression within 4 h. Treatment with ammonium chloride led to a greater than 90% inhibition of numA1 RNA expression within 2 h. In contrast, the addition of DIF-1 completely blocked the decrease in numA1 gene expression caused by starvation. Treatment of vegetative cells with cAMP led to decreases in numA1 RNA expression that were equivalent to those seen with starvation. Western blotting after various morphogen treatments showed that the maintenance of vegetative levels of numA1 RNA by DIF-1 in starved cells was reflected in significantly increased numA1 protein levels. Treatment with cAMP and/or ammonia led to decreased protein expression and each of these morphogens suppressed the stimulatory effects of DIF-1. Protein expression levels of CBP4a, a calcium-dependent binding partner of numA1, were regulated in the same manner as numA1 suggesting this potential co-regulation may be related to their functional relationship. NumA1 is the first calmodulin binding protein shown to be regulated by developmental morphogens in Dictyostelium being upregulated by DIF-1 and down-regulated by cAMP and ammonia. PMID:19000924

  8. Fluorescent probe for high-throughput screening of membrane protein expression

    PubMed Central

    Backmark, A E; Olivier, N; Snijder, A; Gordon, E; Dekker, N; Ferguson, A D

    2013-01-01

    Screening of protein variants requires specific detection methods to assay protein levels and stability in crude mixtures. Many strategies apply fluorescence-detection size-exclusion chromatography (FSEC) using green fluorescent protein (GFP) fusion proteins to qualitatively monitor expression, stability, and monodispersity. However, GFP fusion proteins have several important disadvantages; including false-positives, protein aggregation after proteolytic removal of GFP, and reductions in protein yields without the GFP fusion. Here we describe a FSEC screening strategy based on a fluorescent multivalent NTA probe that interacts with polyhistidine-tags on target proteins. This method overcomes the limitations of GFP fusion proteins, and can be used to rank protein production based on qualitative and quantitative parameters. Domain boundaries of the human G-protein coupled adenosine A2a receptor were readily identified from crude detergent-extracts of a library of construct variants transiently produced in suspension-adapted HEK293-6E cells. Well expressing clones of MraY, an important bacterial infection target, could be identified from a library of 24 orthologs. This probe provides a highly sensitive tool to detect target proteins to expression levels down to 0.02 mg/L in crude lysate, and requires minimal amounts of cell culture. PMID:23776061

  9. Rift Valley Fever Virus Structural and Nonstructural Proteins: Recombinant Protein Expression and Immunoreactivity Against Antisera from Sheep

    PubMed Central

    Faburay, Bonto; Wilson, William; McVey, D. Scott; Drolet, Barbara S.; Weingartl, Hana; Madden, Daniel; Young, Alan; Ma, Wenjun

    2013-01-01

    Abstract The Rift Valley fever virus (RVFV) encodes the structural proteins nucleoprotein (N), aminoterminal glycoprotein (Gn), carboxyterminal glycoprotein (Gc), and L protein, 78-kD, and the nonstructural proteins NSm and NSs. Using the baculovirus system, we expressed the full-length coding sequence of N, NSs, NSm, Gc, and the ectodomain of the coding sequence of the Gn glycoprotein derived from the virulent strain of RVFV ZH548. Western blot analysis using anti-His antibodies and monoclonal antibodies against Gn and N confirmed expression of the recombinant proteins, and in vitro biochemical analysis showed that the two glycoproteins, Gn and Gc, were expressed in glycosylated form. Immunoreactivity profiles of the recombinant proteins in western blot and in indirect enzyme-linked immunosorbent assay against a panel of antisera obtained from vaccinated or wild type (RVFV)-challenged sheep confirmed the results obtained with anti-His antibodies and demonstrated the suitability of the baculo-expressed antigens for diagnostic assays. In addition, these recombinant proteins could be valuable for the development of diagnostic methods that differentiate infected from vaccinated animals (DIVA). PMID:23962238

  10. RNA binding protein and binding site useful for expression of recombinant molecules

    DOEpatents

    Mayfield, Stephen

    2000-01-01

    The present invention relates to a gene expression system in eukaryotic and prokaryotic cells, preferably plant cells and intact plants. In particular, the invention relates to an expression system having a RB47 binding site upstream of a translation initiation site for regulation of translation mediated by binding of RB47 protein, a member of the poly(A) binding protein family. Regulation is further effected by RB60, a protein disulfide isomerase. The expression system is capable of functioning in the nuclear/cytoplasm of cells and in the chloroplast of plants. Translation regulation of a desired molecule is enhanced approximately 100 fold over that obtained without RB47 binding site activation.

  11. RNA binding protein and binding site useful for expression of recombinant molecules

    DOEpatents

    Mayfield, Stephen P.

    2006-10-17

    The present invention relates to a gene expression system in eukaryotic and prokaryotic cells, preferably plant cells and intact plants. In particular, the invention relates to an expression system having a RB47 binding site upstream of a translation initiation site for regulation of translation mediated by binding of RB47 protein, a member of the poly(A) binding protein family. Regulation is further effected by RB60, a protein disulfide isomerase. The expression system is capable of functioning in the nuclear/cytoplasm of cells and in the chloroplast of plants. Translation regulation of a desired molecule is enhanced approximately 100 fold over that obtained without RB47 binding site activation.

  12. Differential expression of the regulator of G protein signaling RGS9 protein in nociceptive pathways of different age rats.

    PubMed

    Kim, Ki Jun; Moriyama, Kumi; Han, Kyung Ream; Sharma, Manohar; Han, Xiaokang; Xie, Guo-xi; Palmer, Pamela Pierce

    2005-11-01

    Regulators of G protein signaling (RGS) proteins are GTPase-activating proteins which act as modulators of G-protein-coupled receptors. RGS9 has two alternative splicing variants. RGS9-1 is expressed in the retina. RGS9-2 is expressed in the brain, especially abundant in the striatum. It is believed to be an essential regulatory component of dopamine and opioid signaling. In this study, we compared the expression of RGS9 proteins in the nervous system of different age groups of rats employing immunocytochemistry. In both 3-week- and 1-year-old rats, RGS9 is expressed abundantly in caudate-putamen, nucleus accumbens, and olfactory tubercle. It is also expressed abundantly in the ventral horn of the spinal cord and the dorsal root ganglion (DRG) cells. Quantitative analysis showed that the intensities of RGS9 expression in 1-year-old rats are higher than those in the 3-week-old rats in caudate-putamen, nucleus accumbens, olfactory tubercle, periaqueductal gray, and gray matter of the spinal cord. In contrast, in thalamic nuclei and locus coeruleus, the intensities of RGS9 immunostaining in 3-week-old rats are higher than in 1-year-old rats. In DRG cells, there is no significant difference between the two age groups. These data suggest that RGS9 is differentially expressed with age. Such differential expression may play an important role in neuronal differentiation and development as well as in neuronal function, such as dopamine and opioid signaling. PMID:16153714

  13. Expression and affinity purification of recombinant proteins from plants

    NASA Technical Reports Server (NTRS)

    Desai, Urvee A.; Sur, Gargi; Daunert, Sylvia; Babbitt, Ruth; Li, Qingshun

    2002-01-01

    With recent advances in plant biotechnology, transgenic plants have been targeted as an inexpensive means for the mass production of proteins for biopharmaceutical and industrial uses. However, the current plant purification techniques lack a generally applicable, economic, large-scale strategy. In this study, we demonstrate the purification of a model protein, beta-glucuronidase (GUS), by employing the protein calmodulin (CaM) as an affinity tag. In the proposed system, CaM is fused to GUS. In the presence of calcium, the calmodulin fusion protein binds specifically to a phenothiazine-modified surface of an affinity column. When calcium is removed with a complexing agent, e.g., EDTA, calmodulin undergoes a conformational change allowing the dissociation of the calmodulin-phenothiazine complex and, therefore, permitting the elution of the GUS-CaM fusion protein. The advantages of this approach are the fast, efficient, and economical isolation of the target protein under mild elution conditions, thus preserving the activity of the target protein. Two types of transformation methods were used in this study, namely, the Agrobacterium-mediated system and the viral-vector-mediated transformation system. Copyright 2002 Elsevier Science (USA).

  14. Protein expressions and their immunogenicity from Riemerella anatipestifer cultured in iron restriction medium.

    PubMed

    Yang, Yifei; Gu, Changqin; Liao, Yonghong; Luo, Qingping; Hu, Xueying; Zhang, Wanpo; Shao, Huabin; Cheng, Guofu

    2013-01-01

    Riemerella anatipestifer was cultured in both iron restriction media and normal media. Two-dimensional gel electrophoresis identified 23 proteins that significantly increased in the iron restriction media. Of them 12 proteins were analyzed with mass spectrography. Nine of 12 proteins belong to 6 different protein families: fibronectin type iii domain protein, secreted subtilase family protein, phosphoglycerate kinase, translation elongation factor, leucine-rich repeat-containing protein, and Galactose-binding domain-like protein. Other 3 proteins were novel with unknown function. Two novel proteins (Riean_1750 and Riean_1752) were expressed in prokaryotic expression systems. The specificities of these 2 novel proteins to R. anatipestifer were confirmed by western-blotting analysis. The ducks immunized with either protein had low mortality challenged by R. anatipestifer, 33.3% and 16.7%, respectively. The ducks developed 100% immunity when immunized with combined Riean_1750 and Riean_1752 proteins. The data suggested 2 novel proteins play important roles in the bacterial survival in the iron restricted environment. They could be used as subunit vaccines of R. anatipestifer. PMID:23755292

  15. A second rhodopsin-like protein in Cyanophora paradoxa: gene sequence and protein expression in a cell-free system.

    PubMed

    Frassanito, Anna Maria; Barsanti, Laura; Passarelli, Vincenzo; Evangelista, Valtere; Gualtieri, Paolo

    2013-08-01

    Here we report the identification and expression of a second rhodopsin-like protein in the alga Cyanophora paradoxa (Glaucophyta), named Cyanophopsin_2. This new protein was identified due to a serendipity event, since the RACE reaction performed to complete the sequence of Cyanophopsin_1, (the first rhodopsin-like protein of C. paradoxa identified in 2009 by our group), amplified a 619 bp sequence corresponding to a portion of a new gene of the same protein family. The full sequence consists of 1175 bp consisting of 849 bp coding DNA sequence and 4 introns of 326 bp. The protein is characterized by an N-terminal region of 47 amino acids, followed by a region with 7 α-helices of 213 amino acids and a C-terminal region of 22 amino acids. This protein showed high identity with Cyanophopsin_1 and other rhodopsin-like proteins of Archea, Bacteria, Fungi and Algae. Cyanophosin_2 (CpR2) was expressed in a cell-free expression system, and characterized by means of absorption spectroscopy. PMID:23851421

  16. Expression and immunological characterization of cardamom mosaic virus coat protein displaying HIV gp41 epitopes.

    PubMed

    Damodharan, Subha; Gujar, Ravindra; Pattabiraman, Sathyamurthy; Nesakumar, Manohar; Hanna, Luke Elizabeth; Vadakkuppattu, Ramanathan D; Usha, Ramakrishnan

    2013-05-01

    The coat protein of cardamom mosaic virus (CdMV), a member of the genus Macluravirus, assembles into virus-like particles when expressed in an Escherichia coli expression system. The N and C-termini of the coat protein were engineered with the Kennedy peptide and the 2F5 and 4E10 epitopes of gp41 of HIV. The chimeric proteins reacted with sera from HIV positive persons and also stimulated secretion of cytokines by peripheral blood mononuclear cells from these persons. Thus, a system based on the coat protein of CdMV can be used to display HIV-1 antigens. PMID:23668610

  17. Elimination of truncated recombinant protein expressed in Escherichia coli by removing cryptic translation initiation site.

    PubMed

    Jennings, Matthew J; Barrios, Adam F; Tan, Song

    2016-05-01

    Undesirable truncated recombinant protein products pose a special expression and purification challenge because such products often share similar chromatographic properties as the desired full length protein. We describe here our observation of both full length and a truncated form of a yeast protein (Gcn5) expressed in Escherichia coli, and the reduction or elimination of the truncated form by mutating a cryptic Shine-Dalgarno or START codon within the Gcn5 coding region. Unsuccessful attempts to engineer in a cryptic translation initiation site into other recombinant proteins suggest that cryptic Shine-Dalgarno or START codon sequences are necessary but not sufficient for cryptic translation in E. coli. PMID:26739786

  18. Selective expression of prion protein in peripheral tissues of the adult mouse.

    PubMed

    Ford, M J; Burton, L J; Morris, R J; Hall, S M

    2002-01-01

    The level of expression of normal cellular prion protein, PrP(c) (cellular prion protein), controls both the rate and the route of neuroinvasive infection, from peripheral entry portal to the CNS. Paradoxically, an overview of the distribution of PrP(c) within tissues outside the CNS is lacking. We have used novel antibodies that recognise cellular prion protein in glutaraldehyde-fixed tissue (in order to optimise immunohistochemical labelling of this conformationally labile protein), in combination with in situ hybridisation, to examine the expression of PrP(c) in peripheral tissues of the adult mouse. We found that although prion protein is expressed in many tissues, it is expressed at high levels only in discrete subpopulations of cells. Prominent amongst these are elements of the "hardwired neuroimmune network" that integrate the body's immune defence and neuroendocrine systems under CNS control. These prion protein-expressing elements include small diameter afferent nerves in the skin and the lamina propria of the aerodigestive tract, sympathetic ganglia and nerves, antigen presenting and processing cells (both follicular and non-follicular dendritic cells) and sub-populations of lymphocytes particularly in skin, gut- and bronchus-associated lymphoid tissues. Prion protein is also expressed in the parasympathetic and enteric nervous systems, in the dispersed neuroendocrine system, and in peripheral nervous system axons and their associated Schwann cells. This selective expression of cellular prion protein provides a variety of alternative routes for the propagation and transport of prion infection entering from peripheral sites, either naturally (via the aerodigestive tract or abraded skin) or experimentally (by intraperitoneal injection) to the brain. Key regulatory cells that express prion protein, and in particular enteroendocrine cells in the mucosal wall of the gut, and dendritic cells that convey pathogens from epithelial layers to secondary lymphoid

  19. Erythroid 5-aminolevulinate synthase mediates the upregulation of membrane band 3 protein expression by iron.

    PubMed

    Huang, Qianchuan; Li, Jinying; Feng, Weihua; Xu, Yanqun; Huang, Zhenxia; Lv, Shuqing; Zhou, Hong; Gao, Lei

    2010-03-01

    Iron deficiency leads to abnormal expression and function of band 3 protein in erythrocytes, but the underlying mechanisms remain elusive. The mRNA of erythroid-specific 5-aminolevulinate synthase (eALAS) contains an iron response element and the eALAS protein is an important mediator of iron utilization by erythrocytes. In this study, we investigated the effect of short hairpin RNA (shRNA) mediated silencing of eALAS on the expression of band 3 protein induced by iron. By real-time RT-PCR and Western blot we showed that at mRNA and protein level iron-induced expression of band 3 protein was lower in eALAS-shRNA transfected K562 cells than in control cells. Of note, the lowest expression was detected in K562 cells cultured in iron deficiency condition (p < 0.01). Thus either iron deficiency or depletion of eALAS could suppress the expression of erythroid band 3 protein. These results demonstrated for the first time that iron and the iron-regulatory system regulate the expression of the erythrocyte membrane proteins. PMID:20087844