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Sample records for acetyltransferase chat expression

  1. Regulatory region in choline acetyltransferase gene directs developmental and tissue-specific expression in transgenic mice.

    PubMed Central

    Lönnerberg, P; Lendahl, U; Funakoshi, H; Arhlund-Richter, L; Persson, H; Ibáñez, C F

    1995-01-01

    Acetylcholine, one of the main neurotransmitters in the nervous system, is synthesized by the enzyme choline acetyltransferase (ChAT; acetyl-CoA:choline O-acetyltransferase, EC 2.3.1.6). The molecular mechanisms controlling the establishment, maintenance, and plasticity of the cholinergic phenotype in vivo are largely unknown. A previous report showed that a 3800-bp, but not a 1450-bp, 5' flanking segment from the rat ChAT gene promoter directed cell type-specific expression of a reporter gene in cholinergic cells in vitro. Now we have characterized a distal regulatory region of the ChAT gene that confers cholinergic specificity on a heterologous downstream promoter in a cholinergic cell line and in transgenic mice. A 2342-bp segment from the 5' flanking region of the ChAT gene behaved as an enhancer in cholinergic cells but as a repressor in noncholinergic cells in an orientation-independent manner. Combined with a heterologous basal promoter, this fragment targeted transgene expression to several cholinergic regions of the central nervous system of transgenic mice, including basal forebrain, cortex, pons, and spinal cord. In eight independent transgenic lines, the pattern of transgene expression paralleled qualitatively and quantitatively that displayed by endogenous ChAT mRNA in various regions of the rat central nervous system. In the lumbar enlargement of the spinal cord, 85-90% of the transgene expression was targeted to the ventral part of the cord, where cholinergic alpha-motor neurons are located. Transgene expression in the spinal cord was developmentally regulated and responded to nerve injury in a similar way as the endogenous ChAT gene, indicating that the 2342-bp regulatory sequence contains elements controlling the plasticity of the cholinergic phenotype in developing and injured neurons. Images Fig. 1 Fig. 2 PMID:7732028

  2. Regulation of choline acetyltransferase expression by 17 β-oestradiol in NSC-34 cells and in the spinal cord.

    PubMed

    Johann, S; Dahm, M; Kipp, M; Zahn, U; Beyer, C

    2011-09-01

    Motoneurones located in the ventral horn of the spinal cord conciliate cholinergic innervation of skeletal muscles. These neurones appear to be exceedingly affected in neurodegenerative diseases such as amyotrophic lateral sclerosis. The dysfunction of motoneurones is typically accompanied by alterations of cholinergic metabolism and signalling, as demonstrated by a decrease in choline acetyltransferase (ChAT) expression. 17 β-Oestradiol (E(2)) is generally accepted as neuroprotective factor in the brain under acute toxic and neurodegenerative conditions and also appears to exert a protective role for motoneurones. In the present study, we attempted to analyse the role of E(2) signalling on ChAT expression in the motoneurone-like cell line NSC-34 and in vivo. In a first step, we demonstrated the presence of oestrogen receptor α and β in NSC-34 cells, as well as in the cervical and lumbar parts, of the male mouse spinal cord. Subsequently, we investigated the effect of E(2) treatment on ChAT expression. The application of E(2) significantly increased the transcription of ChAT in NSC-34 cells and in the cervical but not lumbar part of the spinal cord. Our results indicate that E(2) can influence the cholinergic system by increasing ChAT expression in the mouse spinal cord. This mechanism might support motoneurones, in addition to survival-promoting mechanisms, in the temporal balance toxic or neurodegenerative challenges. PMID:21790808

  3. Cereboost™, an American ginseng extract, improves cognitive function via up-regulation of choline acetyltransferase expression and neuroprotection.

    PubMed

    Shin, Kyungha; Guo, Haiyu; Cha, Yeseul; Ban, Young-Hwan; Seo, Da Woom; Choi, Youngjin; Kim, Tae-Su; Lee, Sung-Pyo; Kim, Jong-Choon; Choi, Ehn-Kyoung; Yon, Jung-Min; Kim, Yun-Bae

    2016-07-01

    In Alzheimer disease (AD), amyloid-beta (Aβ) peptides induce the degeneration of presynaptic cholinergic system, in which decreased activity of enzyme choline acetyltransferase (ChAT) responsible for acetylcholine synthesis is observed. Cereboost™, an extract of American ginseng extract, contains a high concentration of Rb1 ginsenoside which is a well-known ingredient improving human cognitive function. We investigated the effects of Cereboost™ on learning and memory function of mice challenged with an Aβ1-42 peptide and the underlying mechanisms in vitro. Cereboost™ protected against Aβ1-42-induced cytotoxicity in F3.ChAT stem cells, and enhanced the ChAT gene expression. Aβ1-42 injection into the mouse brain impaired the cognitive function, which was recovered by oral administration of Cereboost™. In addition, Cereboost™ restored brain microtubule-associated protein 2 and synaptophysin as well as acetylcholine concentration. The results demonstrate that Cereboost™ administration recovered the cognitive function of AD model animals by enhancing acetylcholine level via ChAT gene expression and neuroprotection. PMID:27112419

  4. Adolescent, but Not Adult, Binge Ethanol Exposure Leads to Persistent Global Reductions of Choline Acetyltransferase Expressing Neurons in Brain

    PubMed Central

    Vetreno, Ryan P.; Broadwater, Margaret; Liu, Wen; Spear, Linda P.; Crews, Fulton T.

    2014-01-01

    During the adolescent transition from childhood to adulthood, notable maturational changes occur in brain neurotransmitter systems. The cholinergic system is composed of several distinct nuclei that exert neuromodulatory control over cognition, arousal, and reward. Binge drinking and alcohol abuse are common during this stage, which might alter the developmental trajectory of this system leading to long-term changes in adult neurobiology. In Experiment 1, adolescent intermittent ethanol (AIE; 5.0 g/kg, i.g., 2-day on/2-day off from postnatal day [P] 25 to P55) treatment led to persistent, global reductions of choline acetyltransferase (ChAT) expression. Administration of the Toll-like receptor 4 agonist lipopolysaccharide to young adult rats (P70) produced a reduction in ChAT+IR that mimicked AIE. To determine if the binge ethanol-induced ChAT decline was unique to the adolescent, Experiment 2 examined ChAT+IR in the basal forebrain following adolescent (P28–P48) and adult (P70–P90) binge ethanol exposure. Twenty-five days later, ChAT expression was reduced in adolescent, but not adult, binge ethanol-exposed animals. In Experiment 3, expression of ChAT and vesicular acetylcholine transporter expression was found to be significantly reduced in the alcoholic basal forebrain relative to moderate drinking controls. Together, these data suggest that adolescent binge ethanol decreases adult ChAT expression, possibly through neuroimmune mechanisms, which might impact adult cognition, arousal, or reward sensitivity. PMID:25405505

  5. Localization of choline acetyltransferase (ChAT) immunoreactivity in the brain of a caecilian amphibian, Dermophis mexicanus (Amphibia: Gymnophiona).

    PubMed

    González, Agustín; López, Jesús M; Sánchez-Camacho, Cristina; Marín, Oscar

    2002-07-01

    The organization of the cholinergic system in the brain of anuran and urodele amphibians was recently studied, and significant differences were noted between both amphibian orders. However, comparable data are not available for the third order of amphibians, the limbless gymnophionans (caecilians). To further assess general and derived features of the cholinergic system in amphibians, we have investigated the distribution of choline acetyltransferase immunoreactive (ChAT-ir) cell bodies and fibers in the brain of the gymnophionan Dermophis mexicanus. This distribution showed particular features of gymnophionans such as the existence of a particularly large cholinergic population in the striatum, the presence of ChAT-ir cells in the mesencephalic tectum, and the organization of the cranial nerve motor nuclei. These peculiarities probably reflect major adaptations of gymnophionans to a fossorial habit. Comparison of our results with those in other vertebrates, including a segmental approach to correlate cell populations across species, shows that the general pattern of organization of cholinergic systems in vertebrates can be modified in certain species in response to adaptative processes that lead to morphological and behavioral modifications of members of a given class of vertebrates, as shown for gymnophionans. PMID:12115707

  6. Recombinant genomes which express chloramphenicol acetyltransferase in mammalian cells

    SciTech Connect

    Gorman, C.M.; Moffat, L.F.; Howard, B.H.

    1982-09-01

    The authors constructed a series of recombinant genomes which directed expression of the enzyme chloramphenicol acetyltransferase (CAT) in mammalian cells. The prototype recombinant in this series, pSV2-cat, consisted of the beta-lactamase gene and origin of replication from pBR322 coupled to a simian virus 40 (SV40) early transcription region into which CAT coding sequences were inserted. Readily measured levels of CAT accumulated within 48 h after the introduction of pSV2-cat DNA into African green monkey kidney CV-1 cells. Because endogenous CAT activity is not present in CV-1 or other mammalian cells, and because rapid, sensitive assays for CAT activity are available, these recombinants provided a uniquely convenient system for monitoring the expression of foreign DNAs in tissue culture cells. To demonstrate the usefulness of this system, we constructed derivatives of pSV2-cat from which part or all of the SV 40 promoter region was removed. Deletion of one copy of the 72-base-pair repeat sequence in the SV40 promoter caused no significant decrease in CAT synthesis in monkey kidney CV-1 cells; however, an additional deletion of 50 base pairs from the second copy of the repeats reduced CAT synthesis to 11% of its level in the wild type. They also constructed a recombinant, pSVO-cat, in which the entire SV40 promoter region was removed and a unique HindIII site was substituted for the insertion of other promoter sequences.

  7. Reduced expression of choline acetyltransferase in vagal motoneurons and gastric motor dysfunction in a 6-OHDA rat model of Parkinson's disease.

    PubMed

    Zheng, Li-Fei; Wang, Zhi-Yong; Li, Xiao-feng; Song, Jin; Hong, Feng; Lian, Hui; Wang, Qian; Feng, Xiao-Yan; Tang, Yuan-yuan; Zhang, Yue; Zhu, Jin-Xia

    2011-10-28

    Parkinson's disease (PD) has been characterized by dopaminergic neuron degeneration in the substantia nigra (SN) accompanied by pathology of the dorsal motor nucleus of the vagus (DMV). PD patients have often experienced gastrointestinal dysfunctions, such as gastroparesis. However, the mechanism underlying these symptoms in PD patients is not clear. In the present study, we investigated alterations of cholinergic and catecholaminergic neurons in the DMV and gastric motor function in rats microinjected with 6-hydroxydopamine (6-OHDA) bilaterally into the SN (referred to as 6-OHDA rats) and explored possible mechanisms. A strain gauge force transducer was used to record gastric motility in vivo. Expression of choline acetyltransferase (ChAT) and tyrosine hydroxylase (TH) was evaluated by immunofluorescence and western blot analysis. Acetylcholine (Ach) content was measured using ultra-performance liquid chromatography tandem mass spectrometry (UPLC/MS/MS) analysis. After treatment with 6-OHDA for 6weeks, 6-OHDA rats exhibited decreased ChAT and enhanced TH expression in the DMV and decreased Ach content in the gastric muscular layer. Delayed gastric emptying and impaired gastric motility in vivo were observed in 6-OHDA rats. The results of the present study indicated that decreased ChAT and enhanced TH expression in the DMV may be correlated with the development of delayed gastric emptying and impaired gastric motility, which may be partly due to the decreased Ach release from the vagus. PMID:21955729

  8. N-Alpha-Acetyltransferases and Regulation of CFTR Expression

    PubMed Central

    Patrick, Anna E.; Hudson, Henry; Thomas, Philip J.

    2016-01-01

    The majority of cystic fibrosis (CF)-causing mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) lead to the misfolding, mistrafficking, and degradation of the mutant protein. Inhibition of degradation does not effectively increase the amount of trafficking competent CFTR, but typically leads to increased ER retention of misfolded forms. Thus, the initial off pathway steps occur early in the processing of the protein. To identify proteins that interact with these early forms of CFTR, in vitro crosslink experiments identified cotranslational partners of the nascent chain of the severe misfolded mutant, G85E CFTR. The mutant preferentially interacts with a subunit of an N-alpha-acetyltransferase A. Based on recent reports that acetylation of the N-termini of some N-end rule substrates control their ubiquitination and subsequent degradation, a potential role for this modification in regulation of CFTR expression was assessed. Knockdown experiments identified two complexes, which affect G85E CFTR proteins levels, NatA and NatB. Effects of the knockdowns on mRNA levels, translation rates, and degradation rates established that the two complexes regulate G85E CFTR through two separate mechanisms. NatA acts indirectly by regulating transcription levels and NatB acts through a previously identified, but incompletely understood posttranslational mechanism. This regulation did not effect trafficking of G85E CFTR, which remains retained in the ER, nor did it alter the degradation rate of CFTR. A mutation predicted to inhibit N-terminal acetylation of CFTR, Q2P, was without effect, suggesting neither system acts directly on CFTR. These results contradict the prediction that N-terminal acetylation of CFTR determines its fitness as a proteasome substrate, but rather NatB plays a role in the conformational maturation of CFTR in the ER through actions on an unidentified protein. PMID:27182737

  9. N-Alpha-Acetyltransferases and Regulation of CFTR Expression.

    PubMed

    Vetter, Ali J; Karamyshev, Andrey L; Patrick, Anna E; Hudson, Henry; Thomas, Philip J

    2016-01-01

    The majority of cystic fibrosis (CF)-causing mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) lead to the misfolding, mistrafficking, and degradation of the mutant protein. Inhibition of degradation does not effectively increase the amount of trafficking competent CFTR, but typically leads to increased ER retention of misfolded forms. Thus, the initial off pathway steps occur early in the processing of the protein. To identify proteins that interact with these early forms of CFTR, in vitro crosslink experiments identified cotranslational partners of the nascent chain of the severe misfolded mutant, G85E CFTR. The mutant preferentially interacts with a subunit of an N-alpha-acetyltransferase A. Based on recent reports that acetylation of the N-termini of some N-end rule substrates control their ubiquitination and subsequent degradation, a potential role for this modification in regulation of CFTR expression was assessed. Knockdown experiments identified two complexes, which affect G85E CFTR proteins levels, NatA and NatB. Effects of the knockdowns on mRNA levels, translation rates, and degradation rates established that the two complexes regulate G85E CFTR through two separate mechanisms. NatA acts indirectly by regulating transcription levels and NatB acts through a previously identified, but incompletely understood posttranslational mechanism. This regulation did not effect trafficking of G85E CFTR, which remains retained in the ER, nor did it alter the degradation rate of CFTR. A mutation predicted to inhibit N-terminal acetylation of CFTR, Q2P, was without effect, suggesting neither system acts directly on CFTR. These results contradict the prediction that N-terminal acetylation of CFTR determines its fitness as a proteasome substrate, but rather NatB plays a role in the conformational maturation of CFTR in the ER through actions on an unidentified protein. PMID:27182737

  10. Postnatal development of nestin positive neurons in rat basal forebrain: different onset and topography with choline acetyltransferase and parvalbumin expression.

    PubMed

    Guo, Kai-Hua; Li, Dong-Pei; Gu, Huai-Yu; Jie-Xu; Yao, Zhi-Bin

    2014-06-01

    Our previous studies identified a sub-population of cholinergic neurons which express nestin in the rostral part of the basal forebrain (BF) in normal adult rats. In the present study, the postnatal developmental patterns of nestin, choline acetyl transferase (ChAT) and parvalbumin (PV) positive neurons were explored by means of immunohistochemistry combined with immunofluorescence double label methods. Compared with early onset of ChAT expression (from P1) and delayed onset of PV expression (from P16), nestin positive activity was detected in the BF from P9 and co-expressed by parts of the ChAT positive neurons within the same region during the whole postnatal development process. However, ChAT and PV were not coexpressed by the neurons within the medial septum-diagonal band of Broca (MS-DBB) of BF. These results might imply a composite of separate development patterns displayed by different subpopulations of cholinergic neurons (nestin positive cholinergic neurons and nestin negative cholinergic neurons) within this region. Moreover, the topographic distribution of nestin, ChAT and PV positive neurons also showed different characteristics. In summary, our present study revealed a remarkable timing and topographic difference on the postnatal development of the nestin expression within the MS-DBB of BF compared with ChAT and PV expression. It is further suggested that nestin is re-expressed by cholinergic neurons in the BF after differentiation but not persisted from neuronal precursor cells. PMID:24657285

  11. Enteric plexuses of two choline-acetyltransferase transgenic mouse lines: chemical neuroanatomy of the fluorescent protein-expressing nerve cells.

    PubMed

    Wilhelm, Márta; Lawrence, J Josh; Gábriel, Robert

    2015-02-01

    We studied cholinergic circuit elements in the enteric nervous system (ENS) of two distinct transgenic mouse lines in which fluorescent protein expression was driven by the choline-acetyltransferase (ChAT) promoter. In the first mouse line, green fluorescent protein was fused to the tau gene. This construct allowed the visualization of the fiber tracts and ganglia, however the nerve cells were poorly resolved. In the second mouse line (ChATcre-YFP), CRE/loxP recombination yielded cytosolic expression of yellow fluorescent protein (YFP). In these preparations the morphology of enteric neurons could be well studied. We also determined the neurochemical identity of ENS neurons in muscular and submucous layers using antibodies against YFP, calretinin (CALR), calbindin (CALB), and vasoactive intestinal peptide (VIP). Confocal microscopic imaging was used to visualize fluorescently-conjugated secondary antibodies. In ChATcre-YFP preparations, YFP was readily apparent in somatodendritic regions of ENS neurons. In the myenteric plexus, YFP/CALR/VIP staining revealed that 34% of cholinergic cells co-labeled with CALR. Few single-stained CR-positive cells were observed. Neither YFP nor CALR co-localized with VIP. In GFP/CALB/CALR staining, all co-localization combinations were represented. In the submucosal plexus, YFP/CALR/VIP staining revealed discrete neuronal populations. However, in separate preparations, double labeling was observed for YFP/CALR and CALR/VIP. In YFP/CALR/CALB staining, all combinations of double staining and triple labeling were verified. In conclusion, the neurochemical coding of ENS neurons in these mouse lines is consistent with many observations in non-transgenic animals. Thus, they provide useful tools for physiological and pharmacological studies on distinct neurochemical subtypes of ENS neurons. PMID:25592616

  12. Suppression of exogenous gene expression by spermidine/spermine N1-acetyltransferase 1 (SSAT1) cotransfection.

    PubMed

    Lee, Seung Bum; Park, Jong Hwan; Woster, Patrick M; Casero, Robert A; Park, Myung Hee

    2010-05-14

    Spermidine/spermine N(1)-acetyltransferase 1 (SSAT1), which catalyzes the N(1)-acetylation of spermidine and spermine to form acetyl derivatives, is a rate-limiting enzyme in polyamine catabolism. We now report a novel activity of transiently transfected SSAT1 in suppressing the exogenous expression of other proteins, i.e. green fluorescent protein (GFP) or GFP-eIF5A. Spermidine/spermine N(1)-acetyltransferase 2 (SSAT2) or inactive SSAT1 mutant enzymes (R101A or R101K) were without effect. The loss of exogenous gene expression is not due to accelerated protein degradation, because various inhibitors of proteases, lysosome, or autophagy did not mitigate the effects. This SSAT1 effect cannot be attributed to the depletion of overall cellular polyamines or accumulation of N(1)-acetylspermidine (N(1)-AcSpd) because of the following: (i) addition of putrescine, spermidine, spermine, or N(1)-AcSpd did not restore the expression of GFP or GFP-eIF5A; (ii) depletion of cellular polyamines with alpha-difluoromethylornithine, an inhibitor of ornithine decarboxylase, did not inhibit exogenous gene expression; and (iii) N(1),N(11)-bis(ethyl)norspermine caused a drastic depletion of cellular polyamines through induction of endogenous SSAT1 but did not block exogenous gene expression. SSAT1 transient transfection did not affect stable expression of GFP, and stably expressed SSAT1 did not affect exogenous expression of GFP, suggesting that only transiently (episomally) expressed SSAT1 blocks exogenous (episomal) expression of other proteins. SSAT1 may regulate exogenous gene expression by blocking steps involved in transcription/translation from an episomal vector by targeting non-polyamine substrate(s) critical for this pathway. PMID:20212040

  13. A method to detect transfected chloramphenicol acetyltransferase gene expression in intact animals

    SciTech Connect

    Narayanan, R.; Jastreboff, M.M.; Chiu, Chang Fang; Ito, Etsuro; Bertino, J.R. )

    1988-01-01

    A rapid procedure is described for assaying chloramphenicol acetyltransferase enzyme activity in intact animals following transfection of the RSV CAT plasmid into mouse bone marrow cells by electroporation. The reconstituted mice were injected with ({sup 14}C)chloramphenicol and ethyl acetate extracts of 24-h urine samples were analyzed by TLC autoradiography for the excretion of {sup 14}C-labeled metabolites. CAT expression in vivo can be detected by the presence of acetylated {sup 14}C-labeled metabolites in the urine within 1 week after bone marrow transplantation and, under the conditions described, these metabolites can be detected for at least 3 months. CAT expression in intact mice as monitored by the urine assay correlates with the CAT expression in the hematopoietic tissues assayed in vitro. This method offers a quick mode of screening for introduced CAT gene expression in vivo without sacrificing the mice.

  14. K-Lysine acetyltransferase 2a regulates a hippocampal gene expression network linked to memory formation

    PubMed Central

    Stilling, Roman M; Rönicke, Raik; Benito, Eva; Urbanke, Hendrik; Capece, Vincenzo; Burkhardt, Susanne; Bahari-Javan, Sanaz; Barth, Jonas; Sananbenesi, Farahnaz; Schütz, Anna L; Dyczkowski, Jerzy; Martinez-Hernandez, Ana; Kerimoglu, Cemil; Dent, Sharon YR; Bonn, Stefan; Reymann, Klaus G; Fischer, Andre

    2014-01-01

    Neuronal histone acetylation has been linked to memory consolidation, and targeting histone acetylation has emerged as a promising therapeutic strategy for neuropsychiatric diseases. However, the role of histone-modifying enzymes in the adult brain is still far from being understood. Here we use RNA sequencing to screen the levels of all known histone acetyltransferases (HATs) in the hippocampal CA1 region and find that K-acetyltransferase 2a (Kat2a)—a HAT that has not been studied for its role in memory function so far—shows highest expression. Mice that lack Kat2a show impaired hippocampal synaptic plasticity and long-term memory consolidation. We furthermore show that Kat2a regulates a highly interconnected hippocampal gene expression network linked to neuroactive receptor signaling via a mechanism that involves nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). In conclusion, our data establish Kat2a as a novel and essential regulator of hippocampal memory consolidation. PMID:25024434

  15. STEREOLOGICAL ESTIMATES OF THE BASAL FOREBRAIN CELL POPULATION IN THE RAT, INCLUDING NEURONS CONTAINING CHOLINE ACETYLTRANSFERASE (ChAT), GLUTAMIC ACID DECARBOXYLASE (GAD) OR PHOSPHATE-ACTIVATED GLUTAMINASE (PAG) AND COLOCALIZING VESICULAR GLUTAMATE TRANSPORTERS (VGluTs)

    PubMed Central

    GRITTI, I.; HENNY, P.; GALLONI, F.; MAINVILLE, L.; MARIOTTI, M.; JONES, B. E.

    2006-01-01

    The basal forebrain (BF) plays an important role in modulating cortical activity and influencing attention, learning and memory. These activities are fulfilled importantly yet not entirely by cholinergic neurons. Noncholinergic neurons also contribute and are comprised by GABAergic neurons and other possibly glutamatergic neurons. The aim of the present study was to estimate the total number of cells in the BF of the rat and the proportions of that total represented by cholinergic, GABAergic and glutamatergic neurons. For this purpose, cells were counted using unbiased stereological methods within the medial septum, diagonal band, magnocellular preoptic nucleus, substantia innominata and globus pallidus in sections stained for Nissl substance and/or the neurotransmitter enzymes, choline acetyltransferase (ChAT), glutamic acid decarboxylase (GAD) or phosphate-activated glutaminase (PAG). In Nissl-stained sections, the total number of neurons in the BF was estimated as ~355,000 and the numbers of ChAT-immuno-positive (+) as ~22,000, GAD+ ~119,000 and PAG+ ~316,000, corresponding to ~5%, ~35% and ~90% of the total. Thus, of the large population of BF neurons, only a small proportion has the capacity to synthesize acetylcholine (ACh), one third to synthesize GABA and the vast majority to synthesize glutamate (Glu). Moreover, through the presence of PAG, a proportion of ACh- and GABA-synthesizing neurons also have the capacity to synthesize Glu. In sections dual fluorescent immunostained for vesicular transporters, VGluT3 and not VGluT2 was present in the cell bodies of most PAG+ and ChAT+ and half the GAD+ cells. Given previous results showing that VGluT2 and not VGluT3 was present in BF axon terminals and not colocalized with VAChT or VGAT, we conclude that the BF cell population influences cortical and subcortical regions through neurons which release ACh, GABA or Glu from their terminals but which in part can also synthesize and release Glu from their soma or

  16. Mutations in HISTONE ACETYLTRANSFERASE1 affect sugar response and gene expression in Arabidopsis

    PubMed Central

    Heisel, Timothy J.; Li, Chun Yao; Grey, Katia M.; Gibson, Susan I.

    2013-01-01

    Nutrient response networks are likely to have been among the first response networks to evolve, as the ability to sense and respond to the levels of available nutrients is critical for all organisms. Although several forward genetic screens have been successful in identifying components of plant sugar-response networks, many components remain to be identified. Toward this end, a reverse genetic screen was conducted in Arabidopsis thaliana to identify additional components of sugar-response networks. This screen was based on the rationale that some of the genes involved in sugar-response networks are likely to be themselves sugar regulated at the steady-state mRNA level and to encode proteins with activities commonly associated with response networks. This rationale was validated by the identification of hac1 mutants that are defective in sugar response. HAC1 encodes a histone acetyltransferase. Histone acetyltransferases increase transcription of specific genes by acetylating histones associated with those genes. Mutations in HAC1 also cause reduced fertility, a moderate degree of resistance to paclobutrazol and altered transcript levels of specific genes. Previous research has shown that hac1 mutants exhibit delayed flowering. The sugar-response and fertility defects of hac1 mutants may be partially explained by decreased expression of AtPV42a and AtPV42b, which are putative components of plant SnRK1 complexes. SnRK1 complexes have been shown to function as central regulators of plant nutrient and energy status. Involvement of a histone acetyltransferase in sugar response provides a possible mechanism whereby nutritional status could exert long-term effects on plant development and metabolism. PMID:23882272

  17. 82-kDa choline acetyltransferase and SATB1 localize to β-amyloid induced matrix attachment regions.

    PubMed

    Winick-Ng, Warren; Caetano, Fabiana A; Winick-Ng, Jennifer; Morey, Trevor M; Heit, Bryan; Rylett, R Jane

    2016-01-01

    The M-transcript of human choline acetyltransferase (ChAT) produces an 82-kDa protein (82-kDa ChAT) that concentrates in nuclei of cholinergic neurons. We assessed the effects of acute exposure to oligomeric amyloid-β1-42 (Aβ1-42) on 82-kDa ChAT disposition in SH-SY5Y neural cells, finding that acute exposure to Aβ1-42 results in increased association of 82-kDa ChAT with chromatin and formation of 82-kDa ChAT aggregates in nuclei. When measured by chromatin immunoprecipitation with next-generation sequencing (ChIP-seq), we identified that Aβ1-42-exposure increases 82-kDa ChAT association with gene promoters and introns. The Aβ1-42-induced 82-kDa ChAT aggregates co-localize with special AT-rich binding protein 1 (SATB1), which anchors DNA to scaffolding/matrix attachment regions (S/MARs). SATB1 had a similar genomic association as 82-kDa ChAT, with both proteins associating with synapse and cell stress genes. After Aβ1-42 -exposure, both SATB1 and 82-kDa ChAT are enriched at the same S/MAR on the APP gene, with 82-kDa ChAT expression attenuating an increase in an isoform-specific APP mRNA transcript. Finally, 82-kDa ChAT and SATB1 have patterned genomic association at regions enriched with S/MAR binding motifs. These results demonstrate that 82-kDa ChAT and SATB1 play critical roles in the response of neural cells to acute Aβ-exposure. PMID:27052102

  18. 82-kDa choline acetyltransferase and SATB1 localize to β-amyloid induced matrix attachment regions

    PubMed Central

    Winick-Ng, Warren; Caetano, Fabiana A.; Winick-Ng, Jennifer; Morey, Trevor M.; Heit, Bryan; Rylett, R. Jane

    2016-01-01

    The M-transcript of human choline acetyltransferase (ChAT) produces an 82-kDa protein (82-kDa ChAT) that concentrates in nuclei of cholinergic neurons. We assessed the effects of acute exposure to oligomeric amyloid-β1–42 (Aβ1–42) on 82-kDa ChAT disposition in SH-SY5Y neural cells, finding that acute exposure to Aβ1–42 results in increased association of 82-kDa ChAT with chromatin and formation of 82-kDa ChAT aggregates in nuclei. When measured by chromatin immunoprecipitation with next-generation sequencing (ChIP-seq), we identified that Aβ1–42 -exposure increases 82-kDa ChAT association with gene promoters and introns. The Aβ1–42 -induced 82-kDa ChAT aggregates co-localize with special AT-rich binding protein 1 (SATB1), which anchors DNA to scaffolding/matrix attachment regions (S/MARs). SATB1 had a similar genomic association as 82-kDa ChAT, with both proteins associating with synapse and cell stress genes. After Aβ1–42 -exposure, both SATB1 and 82-kDa ChAT are enriched at the same S/MAR on the APP gene, with 82-kDa ChAT expression attenuating an increase in an isoform-specific APP mRNA transcript. Finally, 82-kDa ChAT and SATB1 have patterned genomic association at regions enriched with S/MAR binding motifs. These results demonstrate that 82-kDa ChAT and SATB1 play critical roles in the response of neural cells to acute Aβ -exposure. PMID:27052102

  19. Construction and Use of a Replication-Competent Human Immunodeficiency Virus (HIV-1) that Expresses the Chloramphenicol Acetyltransferase Enzyme

    NASA Astrophysics Data System (ADS)

    Terwilliger, E. F.; Godin, B.; Sodroski, J. G.; Haseltine, W. A.

    1989-05-01

    The construction and properties of an infectious human immunodeficiency virus (HIV) that expresses the bacterial gene chloramphenicol acetyltransferase are described. This virus can be used in vitro to screen for drugs that inhibit HIV infection. The marked virus may also be used to trace the routes of infection from the site of inoculation in animal experiments.

  20. P300 acetyltransferase regulates fatty acid synthase expression, lipid metabolism and prostate cancer growth.

    PubMed

    Gang, Xiaokun; Yang, Yinhui; Zhong, Jian; Jiang, Kui; Pan, Yunqian; Karnes, R Jeffrey; Zhang, Jun; Xu, Wanhai; Wang, Guixia; Huang, Haojie

    2016-03-22

    De novo fatty acid (FA) synthesis is required for prostate cancer (PCa) survival and progression. As a key enzyme for FA synthesis fatty acid synthase (FASN) is often overexpressed in human prostate cancers and its expression correlates with worse prognosis and poor survival. P300 is an acetyltransferase that acts as a transcription co-activator. Increasing evidence suggests that P300 is a major PCa promoter, although the underlying mechanism remains poorly understood. Here, we demonstrated that P300 binds to and increases histone H3 lysine 27 acetylation (H3K27Ac) in the FASN gene promoter. We provided evidence that P300 transcriptionally upregulates FASN expression and promotes lipid accumulation in human PCa cells in culture and Pten knockout prostate tumors in mice. Pharmacological inhibition of P300 decreased FASN expression and lipid droplet accumulation in PCa cells. Immunohistochemistry analysis revealed that expression of P300 protein positively correlates with FASN protein levels in a cohort of human PCa specimens. We further showed that FASN is a key mediator of P300-induced growth of PCa cells in culture and in mice. Together, our findings demonstrate P300 as a key factor that regulates FASN expression, lipid accumulation and cell growth in PCa. They also suggest that this regulatory pathway can serve as a new therapeutic target for PCa treatment. PMID:26934656

  1. An aminoglycoside sensing riboswitch controls the expression of aminoglycoside resistance acetyltransferase and adenyltransferases.

    PubMed

    Chen, Dongrong; Murchie, Alastair I H

    2014-10-01

    The emergence of antibiotic resistance in human pathogens is an increasing threat to public health. The fundamental mechanisms that control the high levels of expression of antibiotic resistance genes are not yet completely understood. The aminoglycosides are one of the earliest classes of antibiotics that were introduced in the 1940s. In the clinic aminoglycoside resistance is conferred most commonly through enzymatic modification of the drug although resistance through enzymatic modification of the target rRNA through methylation or the overexpression of efflux pumps is also appearing. An aminoglycoside sensing riboswitch has been identified that controls expression of the aminoglycoside resistance genes that encode the aminoglycoside acetyltransferase (AAC) and aminoglycoside nucleotidyltransferase (ANT) (adenyltransferase (AAD)) enzymes. AAC and ANT cause resistance to aminoglycoside antibiotics through modification of the drugs. Expression of the AAC and ANT resistance genes is regulated by aminoglycoside binding to the 5' leader RNA of the aac/aad genes. The aminoglycoside sensing RNA is also associated with the integron cassette system that captures antibiotic resistance genes. Specific aminoglycoside binding to the leader RNA induces a structural transition in the leader RNA, and consequently induction of resistance protein expression. Reporter gene expression, direct measurements of drug RNA binding, chemical probing and UV cross-linking combined with mutational analysis demonstrated that the leader RNA functioned as an aminoglycoside sensing riboswitch in which drug binding to the leader RNA leads to the induction of aminoglycoside antibiotic resistance. This article is part of a Special Issue entitled: Riboswitches. PMID:24631585

  2. Targeting of a histone acetyltransferase domain to a promoter enhances protein expression levels in mammalian cells.

    PubMed

    Kwaks, T H J; Sewalt, R G A B; van Blokland, R; Siersma, T J; Kasiem, M; Kelder, A; Otte, A P

    2005-01-12

    Silencing of transfected genes in mammalian cells is a fundamental problem that probably involves the (in)accessibility status of chromatin. A potential solution to this problem is to provide a cell with protein factors that make the chromatin of a promoter more open or accessible for transcription. We tested this by targeting such proteins to different promoters. We found that targeting the p300 histone acetyltransferase (HAT) domain to strong viral or cellular promoters is sufficient to result in higher expression levels of a reporter protein. In contrast, targeting the chromatin-remodeling factor Brahma does not result in stable, higher protein expression levels. The long-term effects of the targeted p300HAT domain on protein expression levels are positively reinforced, when also anti-repressor elements are applied to flank the reporter construct. These elements were previously shown to be potent blockers of chromatin-associated repressors. The simultaneous application of the targeted p300HAT domain and anti-repressor elements conveys long-term stability to protein expression. Whereas no copy number dependency is achieved by targeting of the p300HAT domain alone, copy number dependency is improved when anti-repressor elements are included. We conclude that targeting of protein domains such as HAT domains helps to facilitate expression of transfected genes in mammalian cells. However, the simultaneous application of other genomic elements such as the anti-repressor elements prevents silencing more efficiently. PMID:15607223

  3. P300 acetyltransferase regulates fatty acid synthase expression, lipid metabolism and prostate cancer growth

    PubMed Central

    Zhong, Jian; Jiang, Kui; Pan, Yunqian; Karnes, R. Jeffrey; Zhang, Jun; Xu, Wanhai; Wang, Guixia; Huang, Haojie

    2016-01-01

    De novo fatty acid (FA) synthesis is required for prostate cancer (PCa) survival and progression. As a key enzyme for FA synthesis fatty acid synthase (FASN) is often overexpressed in human prostate cancers and its expression correlates with worse prognosis and poor survival. P300 is an acetyltransferase that acts as a transcription co-activator. Increasing evidence suggests that P300 is a major PCa promoter, although the underlying mechanism remains poorly understood. Here, we demonstrated that P300 binds to and increases histone H3 lysine 27 acetylation (H3K27Ac) in the FASN gene promoter. We provided evidence that P300 transcriptionally upregulates FASN expression and promotes lipid accumulation in human PCa cells in culture and Pten knockout prostate tumors in mice. Pharmacological inhibition of P300 decreased FASN expression and lipid droplet accumulation in PCa cells. Immunohistochemistry analysis revealed that expression of P300 protein positively correlates with FASN protein levels in a cohort of human PCa specimens. We further showed that FASN is a key mediator of P300-induced growth of PCa cells in culture and in mice. Together, our findings demonstrate P300 as a key factor that regulates FASN expression, lipid accumulation and cell growth in PCa. They also suggest that this regulatory pathway can serve as a new therapeutic target for PCa treatment. PMID:26934656

  4. Retinal, pineal and diencephalic expression of frog arylalkylamine N-acetyltransferase-1.

    PubMed

    Isorna, Esther; Besseau, Laurence; Boeuf, Gilles; Desdevises, Yves; Vuilleumier, Robin; Alonso-Gómez, Angel L; Delgado, María J; Falcón, Jack

    2006-06-27

    The arylalkylamine N-acetyltransferase (AANAT) is a key enzyme in the rhythmic production of melatonin. Two Aanats are expressed in Teleost fish (Aanat1 in the retina and Aanat2 in the pineal organ) but only Aanat1 is found in tetrapods. This study reports the cloning of Aanat1 from R. perezi. Transcripts were mainly expressed in the retina, diencephalon, intestine and testis. In the retina and pineal organ, Aanat1 expression was in the photoreceptor cells. Expression was also seen in ependymal cells of the 3rd ventricle and discrete cells of the suprachiasmatic area. The expression of Aanat1 in both the retina and pineal organ, and the absence of Aanat2 suggests that green frog resembles more to birds and mammals than to Teleost fish, as far as Aanat is concerned. The significance of Aanat1 in extra-pineal and extra-retinal tissues remains to be elucidated; in the diencephalon, it might be associated to the so-called deep brain photoreceptor cells. PMID:16687207

  5. Differential effect of lithium on spermidine/spermine N1-acetyltransferase expression in suicidal behaviour.

    PubMed

    Squassina, Alessio; Manchia, Mirko; Chillotti, Caterina; Deiana, Valeria; Congiu, Donatella; Paribello, Francesco; Roncada, Paola; Soggiu, Alessio; Piras, Cristian; Urbani, Andrea; Robertson, George S; Keddy, Paul; Turecki, Gustavo; Rouleau, Guy A; Alda, Martin; Del Zompo, Maria

    2013-11-01

    An altered polyamine system has been suggested to play a key role in mood disorders and suicide, a hypothesis corroborated by the evidence that lithium inhibits the polyamine mediated stress response in the rat brain. Recent post-mortem studies have shown that spermidine/spermine N1-acetyltransferase (SAT1), the key regulator of cellular polyamine content, is under-expressed in brains from suicide victims compared to controls. In our study we tested the effect of in vitro lithium treatment on SAT1 gene and protein expression in B lymphoblastoid cell lines (BLCLs) from bipolar disorder (BD) patients who committed suicide (and for which BLCLs were collected prior to their death), BD patients with high and low risk of suicide and a sample of non-psychiatric controls. Baseline mRNA levels were similar in the four groups of subjects (p > 0.05). Lithium had no effect in suicide completers (p > 0.05) while it significantly increased SAT1 expression in the high risk (p < 0.001) and low risk (p < 0.01) groups as well as in controls (p < 0.001). Protein and mRNA levels were not correlated; lithium significantly reduced protein levels only in the control sample (p < 0.05). Our findings suggest that SAT1 transcription is influenced by lithium and that this effect is altered in BD patients who completed suicide, further supporting a role for polyamines in suicide. PMID:23768751

  6. Human Neural Stem Cells Overexpressing Choline Acetyltransferase Restore Unconditioned Fear in Rats with Amygdala Injury

    PubMed Central

    Shin, Kyungha; Cha, Yeseul; Kim, Kwang Sei; Choi, Ehn-Kyoung; Choi, Youngjin; Guo, Haiyu; Ban, Young-Hwan; Kim, Jong-Choon; Park, Dongsun; Kim, Yun-Bae

    2016-01-01

    Amygdala is involved in the fear memory that recognizes certain environmental cues predicting threatening events. Manipulation of neurotransmission within the amygdala affects the expression of conditioned and unconditioned emotional memories such as fear freezing behaviour. We previously demonstrated that F3.ChAT human neural stem cells (NSCs) overexpressing choline acetyltransferase (ChAT) improve cognitive function of Alzheimer's disease model rats with hippocampal or cholinergic nerve injuries by increasing acetylcholine (ACh) level. In the present study, we examined the effect of F3.ChAT cells on the deficit of unconditioned fear freezing. Rats given N-methyl-d-aspartate (NMDA) in their amygdala 2 weeks prior to cat odor exposure displayed very short resting (freezing) time compared to normal animals. NMDA induced neuronal degeneration in the amygdala, leading to a decreased ACh concentration in cerebrospinal fluid. However, intracerebroventricular transplantation of F3.ChAT cells attenuated amygdala lesions 4 weeks after transplantation. The transplanted cells were found in the NMDA-injury sites and produced ChAT protein. In addition, F3.ChAT-receiving rats recuperated freezing time staying remote from the cat odor source, according to the recovery of brain ACh concentration. The results indicate that human NSCs overexpressing ChAT may facilitate retrieval of unconditioned fear memory by increasing ACh level. PMID:27087745

  7. Human Neural Stem Cells Overexpressing Choline Acetyltransferase Restore Unconditioned Fear in Rats with Amygdala Injury.

    PubMed

    Shin, Kyungha; Cha, Yeseul; Kim, Kwang Sei; Choi, Ehn-Kyoung; Choi, Youngjin; Guo, Haiyu; Ban, Young-Hwan; Kim, Jong-Choon; Park, Dongsun; Kim, Yun-Bae

    2016-01-01

    Amygdala is involved in the fear memory that recognizes certain environmental cues predicting threatening events. Manipulation of neurotransmission within the amygdala affects the expression of conditioned and unconditioned emotional memories such as fear freezing behaviour. We previously demonstrated that F3.ChAT human neural stem cells (NSCs) overexpressing choline acetyltransferase (ChAT) improve cognitive function of Alzheimer's disease model rats with hippocampal or cholinergic nerve injuries by increasing acetylcholine (ACh) level. In the present study, we examined the effect of F3.ChAT cells on the deficit of unconditioned fear freezing. Rats given N-methyl-d-aspartate (NMDA) in their amygdala 2 weeks prior to cat odor exposure displayed very short resting (freezing) time compared to normal animals. NMDA induced neuronal degeneration in the amygdala, leading to a decreased ACh concentration in cerebrospinal fluid. However, intracerebroventricular transplantation of F3.ChAT cells attenuated amygdala lesions 4 weeks after transplantation. The transplanted cells were found in the NMDA-injury sites and produced ChAT protein. In addition, F3.ChAT-receiving rats recuperated freezing time staying remote from the cat odor source, according to the recovery of brain ACh concentration. The results indicate that human NSCs overexpressing ChAT may facilitate retrieval of unconditioned fear memory by increasing ACh level. PMID:27087745

  8. Enhanced ubiquitination and proteasomal degradation of catalytically deficient human choline acetyltransferase mutants.

    PubMed

    Morey, Trevor M; Albers, Shawn; Shilton, Brian H; Rylett, R Jane

    2016-05-01

    Choline acetyltransferase (ChAT) is essential for cholinergic neuron function as it mediates synthesis of the neurotransmitter acetylcholine. ChAT mutations have been linked to the neuromuscular disorder congenital myasthenic syndrome (CMS). One CMS-related ChAT mutation, V18M, reduces enzyme activity and cellular protein levels, and is positioned within a highly conserved proline-rich motif with the sequence 14 PKLPVPP20 . We demonstrate that N-terminal truncation that includes this proline-rich motif, as well as mutation of prolines-17/19 together to alanine (P17A/P19A), dramatically reduces ChAT steady-state protein levels and cellular activity when expressed in cholinergic SN56 neural cells. The in vitro activity of bacterially expressed recombinant P17A/P19A-ChAT is also reduced, although this is not caused by changes in protein secondary structure or thermal stability. Treatment of SN56 cells with the proteasome inhibitor MG132 increases cellular P17A/P19A-ChAT steady-state protein levels, and by immunoprecipitation we found that ChAT is ubiquitinated and that polyubiquitination of P17A/P19A-ChAT is increased compared to wild-type (WT) ChAT. Using a novel fluorescent-biorthogonal pulse-chase protocol in SN56 cells, we determined that the protein half-life of P17A/P19A-ChAT (2.2 h) is substantially reduced compared to WT-ChAT (19.7 h). Lastly, we show that two CMS-related ChAT mutants (V18M and A513T) have enhanced ubiquitination, and that treatment with MG132 can partially restore both the steady-state protein levels as well as cellular activity of some CMS-mutant ChAT. These results identify a novel mechanism for regulation of ChAT through the ubiquitin-proteasome system that is influenced by the conserved N-terminal proline-rich motif of ChAT and may be implicated in CMS pathology. Choline acetyltransferase (ChAT) synthesizes acetylcholine in cholinergic neurons. In this study we find that steady-state protein levels of human 69-kDa ChAT are regulated by

  9. Co-expression of GAD67 and choline acetyltransferase in neurons in the mouse spinal cord: A focus on lamina X.

    PubMed

    Gotts, Jittima; Atkinson, Lucy; Yanagawa, Yuchio; Deuchars, Jim; Deuchars, Susan A

    2016-09-01

    Lamina X of the spinal cord is a functionally diverse area with roles in locomotion, autonomic control and processing of mechano and nociceptive information. It is also a neurochemically diverse region. However, the different populations of cells in lamina X remain to be fully characterised. To determine the co-localisation of the enzymes responsible for the production of GABA and acetylcholine (which play major roles in the spinal cord) in lamina X of the adult and juvenile mouse, we used a transgenic mouse expressing green fluorescent protein (GFP) in glutamate decarboxylase 67 (GAD67) neurons, combined with choline acetyltransferase (ChAT) immunohistochemistry. ChAT-immunoreactive (IR) and GAD67-GFP containing neurons were observed in lamina X of both adult and juvenile mice and in both age groups a population of cells containing both ChAT-IR and GAD67-GFP were observed in lumbar, thoracic and cervical spinal cord. Such dual labelled cells were predominantly located ventral to the central canal. Immunohistochemistry for vesicular acetylcholine transporter (VAChT) and GAD67 revealed a small number of double labelled terminals located lateral, dorsolateral and ventrolateral to the central canal. This study therefore describes in detail a population of ChAT-IR/GAD67-GFP neurons predominantly ventral to the central canal of the cervical, thoracic and lumbar spinal cord of adult and juvenile mice. These cells potentially correspond to a sub-population of the cholinergic central canal cluster cells which may play a unique role in controlling spinal cord circuitry. PMID:27378584

  10. MYST2 acetyltransferase expression and Histone H4 Lysine acetylation are suppressed in AML.

    PubMed

    Sauer, Tim; Arteaga, Maria Francisca; Isken, Fabienne; Rohde, Christian; Hebestreit, Katja; Mikesch, Jan-Henrik; Stelljes, Matthias; Cui, Chunhong; Zhou, Fengbiao; Göllner, Stefanie; Bäumer, Nicole; Köhler, Gabriele; Krug, Utz; Thiede, Christian; Ehninger, Gerhard; Edemir, Bayram; Schlenke, Peter; Berdel, Wolfgang E; Dugas, Martin; Müller-Tidow, Carsten

    2015-09-01

    Chromatin-modifying enzymes are frequently altered in acute myeloid leukemia (AML). In the current study, we identified MYST2, a core histone acetyltransferase, to be suppressed in blast cells from AML patients compared with nonmalignant hematopoietic progenitor cells. Functionally, loss of MYST2 accelerated leukemic growth and colony formation, while forced expression of MYST2 induced H4K5 acetylation (H4K5Ac) and suppressed hematopoietic progenitor cell growth. Consistently, global H4K5Ac levels were frequently decreased in AML blasts. Low levels of H4K5Ac were most prominent in patients with complex karyotype AML and were associated with inferior overall survival in univariate but not multivariate analysis. ChIP-seq experiments in primary AML patients' blasts revealed widespread H4K5Ac deregulation, most prominent at gene promoters. Taken together, MYST2 is a repressed growth suppressor in AML mediating reduced acetylation of histone 4 at residue 5 and is associated with inferior AML patient survival. PMID:26072331

  11. The histone acetyltransferase p300 inhibitor C646 reduces pro-inflammatory gene expression and inhibits histone deacetylases

    PubMed Central

    van den Bosch, Thea; Boichenko, Alexander; Leus, Niek G. J.; Eleni Ourailidou, Maria; Wapenaar, Hannah; Rotili, Dante; Mai, Antonello; Imhof, Axel; Bischoff, Rainer; Haisma, Hidde J.; Dekker, Frank J.

    2016-01-01

    Lysine acetylations are reversible posttranslational modifications of histone and non-histone proteins that play important regulatory roles in signal transduction cascades and gene expression. Lysine acetylations are regulated by histone acetyltransferases as writers and histone deacetylases as erasers. Because of their role in signal transduction cascades, these enzymes are important players in inflammation. Therefore, applications of histone acetyltransferase inhibitors to reduce inflammatory responses are interesting. Among the few histone acetyltransferase inhibitors described, C646 is one of the most potent (Ki of 0.4 μM for histone acetyltransferase p300). C646 was described to regulate the NF-κB pathway; an important pathway in inflammatory responses, which is regulated by acetylation. Interestingly, this pathway has been implicated in asthma and COPD. Therefore we hypothesized that via regulation of the NF-κB signaling pathway, C646 can inhibit pro-inflammatory gene expression, and have potential for the treatment of inflammatory lung diseases. In line with this, here we demonstrate that C646 reduces pro-inflammatory gene expression in RAW264.7 murine macrophages and murine precision-cut lung slices. To unravel its effects on cellular substrates we applied mass spectrometry and found, counterintuitively, a slight increase in acetylation of histone H3. Based on this finding, and structural features of C646, we presumed inhibitory activity of C646 on histone deacetylases, and indeed found inhibition of histone deacetylases from 7 μM and higher concentrations. This indicates that C646 has potential for further development towards applications in the treatment of inflammation, however, its newly discovered lack of selectivity at higher concentrations needs to be taken into account. PMID:26718586

  12. The histone acetyltransferase p300 inhibitor C646 reduces pro-inflammatory gene expression and inhibits histone deacetylases.

    PubMed

    van den Bosch, Thea; Boichenko, Alexander; Leus, Niek G J; Ourailidou, Maria E; Wapenaar, Hannah; Rotili, Dante; Mai, Antonello; Imhof, Axel; Bischoff, Rainer; Haisma, Hidde J; Dekker, Frank J

    2016-02-15

    Lysine acetylations are reversible posttranslational modifications of histone and non-histone proteins that play important regulatory roles in signal transduction cascades and gene expression. Lysine acetylations are regulated by histone acetyltransferases as writers and histone deacetylases as erasers. Because of their role in signal transduction cascades, these enzymes are important players in inflammation. Therefore, histone acetyltransferase inhibitors could reduce inflammatory responses. Among the few histone acetyltransferase inhibitors described, C646 is one of the most potent (Ki of 0.4μM for histone acetyltransferase p300). C646 was described to affect the NF-κB pathway; an important pathway in inflammatory responses, which is regulated by acetylation. This pathway has been implicated in asthma and COPD. Therefore, we hypothesized that via regulation of the NF-κB signaling pathway, C646 can inhibit pro-inflammatory gene expression, and have potential for the treatment of inflammatory lung diseases. In line with this, we demonstrate here that C646 reduces pro-inflammatory gene expression in RAW264.7 murine macrophages and murine precision-cut lung slices. To unravel its effects on cellular substrates we applied mass spectrometry and found, counterintuitively, a slight increase in acetylation of histone H3. Based on this finding, and structural features of C646, we presumed inhibitory activity of C646 on histone deacetylases, and indeed found inhibition of histone deacetylases from 7μM and higher concentrations. This indicates that C646 has potential for further development towards applications in the treatment of inflammation, however, its newly discovered lack of selectivity at higher concentrations needs to be taken into account. PMID:26718586

  13. Microarray analysis of genes differentially expressed in melatonin-rich transgenic rice expressing a sheep serotonin N-acetyltransferase.

    PubMed

    Byeon, Yeong; Park, Sangkyu; Kim, Young Soon; Back, Kyoungwhan

    2013-11-01

    Transgenic rice plants overexpressing a sheep serotonin N-acetyltransferase led to an enhanced production of melatonin with various physiological effects, including seminal root elongation and resistance against cold and oxidative stress, which raises the possibility that melatonin may alter gene expression profiles in the transgenic rice. Therefore, we performed a microarray analysis to investigate the regulatory role of melatonin using the melatonin-rich transgenic rice. We identified 260 and 204 genes that were up- or downregulated in the melatonin-rich transgenic rice when compared with the wild type. Of these, 20 upregulated genes were identified in the seedlings of melatonin-rich rice at more than twice the levels in the wild type (P < 0.05), while 23 downregulated genes were also detected. The representative upregulated genes included caleosin, a Ca(2+) -binding oil-body surface protein involved in the degradation of lipids stored in oil bodies and various signaling proteins such as a cyclin F-box protein and leucine-rich repeat protein. In contrast, jasmonate-induced protein, senescence-associated protein, and polygalacturonase were included in the downregulated gene group. These results suggest that melatonin has an important role in modulating a wide range of gene expression, reflecting its pleiotropic physiological roles in plant growth and development. PMID:23889160

  14. Choline acetyltransferase mutations causing congenital myasthenic syndrome: molecular findings and genotype-phenotype correlations

    PubMed Central

    Arredondo, Juan; Lara, Marian; Gospe, Sídney M.; Mazia, Claudio G.; Vaccarezza, Maria; Garcia-Erro, Marcela; Bowe, Constance; Chang, Celia; Mezei, Michelle; Maselli, Ricardo A.

    2015-01-01

    Choline acetyltransferase catalyzes the synthesis of acetylcholine at cholinergic nerves. Mutations in human CHAT cause a congenital myasthenic syndrome (CMS) due to impaired synthesis of ACh; this severe variant of the disease is frequently associated with unexpected episodes of potentially fatal apnea. The severity of this condition varies remarkably, and the molecular factors determining this variability are poorly understood. Furthermore, genotype–phenotype correlations have been difficult to establish in patients with biallelic mutations. We analyzed the protein expression of seven ChAT mutations, p.Val136Met, p.Arg207His, p.Arg186Trp, p.Val194Leu, p.Pro211Ala, p.Arg566Cys and p.Ser694Cys, in HEK-293 cells to phosphorylated ChAT, determined their enzyme kinetics and thermal instability, and examined their structural changes. Three mutations, p.Arg207His, p.Arg186Trp and p.Arg566Cys, are novel, and p.Val136Met and p.Arg207His are homozygous in three families and associated with severe disease. The characterization of mutants showed a decrease in the overall catalytic efficiency of ChAT; in particular, those located near the active-site tunnel produced the most seriously disruptive phenotypic effects. On the other hand, p.Val136Met is located far from both active and substrate-binding sites produced the most drastic reduction of ChAT expression. Overall, CHAT mutations producing low enzyme expression and severe kinetic effects are associated with the most severe phenotypes. PMID:26080897

  15. Popular Chat Day Q & A

    MedlinePlus

    ... Day / Popular Chat Day Q & A Popular Chat Day Q & A Print Read students’ most popular questions ... Cool Order Free Materials National Drugs & Alcohol Chat Day Chat Day Participant FAQs Popular Chat Day Q & ...

  16. The human serotonin N-acetyltransferase (EC 2.3.1.87) gene (AANAT): Structure, chromosomal localization, and tissue expression

    SciTech Connect

    Coon, S.L.; Bernard, M.; Roseboom, P.H.

    1996-05-15

    Serotonin N-acetyltransferase (arylalkylamine N-acetyltransferase, AA-NAT, HGMW-approved symbol AANAT;EC 2.3.1.87) is the penultimate enzyme in melatonin synthesis and controls the night/day rhythm in melatonin production in the vertebrate pineal gland. We have found that the human AA-NAT gene spans {approx}2.5 kb, contains four exons, and is located at chromosome 17q25. The open reading frame encodes a 23.2-kDa protein that is {approx}80% identical to sheep and rat AA-NAT. The AA-NAT transcript ({approx}1 kb) is highly abundant in the pineal gland and is expressed at lower levels in the retina and in the Y79 retinoblastoma cell line. AA-NAT mRNA is also detectable at low levels in several brain regions and the pituitary gland, but not in several peripheral tissues examined. Brain and pituitary AA-NAT could modulate serotonin-dependent aspects of human behavior and pituitary function. 31 refs., 5 figs.

  17. In vivo knockdown of basal forebrain p75 neurotrophin receptor stimulates choline acetyltransferase activity in the mature hippocampus.

    PubMed

    Barrett, Graham L; Naim, Timur; Trieu, Jennifer; Huang, Mengjie

    2016-05-01

    This study seeks to determine whether knockdown of basal forebrain p75 neurotrophin receptor (p75(NTR) ) expression elicits increased hippocampal choline acetyltransferase (ChAT) activity in mature animals. Antisense (AS) oligonucleotides (oligos) targeting p75(NTR) were infused into the medial septal area of mature rats continuously for 4 weeks. In all rats, the cannula outlet was placed equidistant between the left and the right sides of the vertical diagonal band of Broca. We tested phosphorothioate (PS), morpholino (Mo), and gapmer (mixed PS/RNA) oligos. Gapmer AS infusions of 7.5 and 22 μg/day decreased septal p75(NTR) mRNA by 34% and 48%, respectively. The same infusions increased hippocampal ChAT activity by 41% and 55%. Increased hippocampal ChAT activity correlated strongly with septal p75(NTR) downregulation in individual rats. Infusions of PS and Mo AS oligos did not downregulate p75(NTR) mRNA or stimulate ChAT activity. These results demonstrate that p75(NTR) can dynamically regulate hippocampal ChAT activity in the mature CNS. They also reveal the different efficacies of three diverse AS oligo chemistries when infused intracerebrally. Among the three types, gapmer oligos worked best. PMID:26864466

  18. Melatonin production in Escherichia coli by dual expression of serotonin N-acetyltransferase and caffeic acid O-methyltransferase.

    PubMed

    Byeon, Yeong; Back, Kyoungwhan

    2016-08-01

    Melatonin is a well-known bioactive molecule produced in animals and plants and a well-studied natural compound. Two enzymatic steps are required for the biosynthesis of melatonin from serotonin. First, serotonin N-acetyltransferase (SNAT) catalyzes serotonin to N-acetylserotonin (NAS) followed by the action of N-acetylserotonin O-methyltransferase (ASMT), resulting in the synthesis of O-methylated NAS, also known as melatonin. Attempts to document melatonin production in Escherichia coli have been unsuccessful to date due to either low enzyme activity or inactive ASMT expression. Here, we employed caffeic acid O-methyltransferase (COMT) instead of ASMT, as COMT is a multifunctional enzyme that has ASMT activity as well. Among several combinations of dual expression cassettes, recombinant E. coli that expressed sheep SNAT with rice COMT produced a high quantity of melatonin, which was measured in a culture medium (1.46 mg/L in response to 1 mM serotonin). This level was several orders of magnitude higher than that produced in transgenic rice and tomato overexpressing sheep SNAT and ASMT, respectively. This heterologous expression system can be widely employed to screen various putative SNAT or ASMT genes from animals and plants as well as to overproduce melatonin in various useful microorganisms. PMID:27005412

  19. Modulation of the biliary expression of arylalkylamine N-acetyltransferase alters the autocrine proliferative responses of cholangiocytes

    PubMed Central

    Renzi, Anastasia; DeMorrow, Sharon; Onori, Paolo; Carpino, Guido; Mancinelli, Romina; Meng, Fanyin; Venter, Julie; White, Mellanie; Franchitto, Antonio; Francis, Heather; Han, Yuyan; Ueno, Yoshiyuki; Dusio, Giuseppina; Jensen, Kendal J; Greene, John J; Glaser, Shannon; Gaudio, Eugenio; Alpini, Gianfranco

    2012-01-01

    Background & Aims Secretin stimulates ductal secretion by interacting with secretin receptor (SR) activating cAMP⇒CFTR⇒Cl−/HCO3− AE2 signaling that is elevated by biliary hyperplasia. Cholangiocytes secrete several neuroendocrine factors regulating biliary functions by autocrine mechanisms. Melatonin inhibits biliary growth and secretin-stimulated choleresis in cholestatic bile duct ligated (BDL) rats by interaction with melatonin type 1 (MT1) receptor via downregulation of cAMP-dependent signaling. No data exists regarding the role of melatonin synthesized locally by cholangiocytes in the autocrine regulation of biliary growth and function. Methods In this study, we evaluated: (i) the expression of arylalkylamine N-acetyltransferase (AANAT, the rate-limiting enzyme for melatonin synthesis from serotonin) in cholangiocytes; and (ii) the effect of local modulation of biliary AANAT expression on the autocrine proliferative/secretory responses of cholangiocytes. Results In the liver, cholangiocytes (and to lower extent BDL hepatocytes) expressed AANAT. AANAT expression and melatonin secretion: (i) increased in BDL compared to normal rats and BDL rats treated with melatonin; and (ii) decreased in normal and BDL rats treated with AANAT Vivo-Morpholino compared to controls. The decrease in AANAT expression and subsequent lower melatonin secretion by cholangiocytes was associated with increased biliary proliferation and increased SR, CFTR, and Cl−/HCO3− AE2 expression. Overexpression of AANAT in cholangiocyte cell lines decreased the basal proliferative rate and expression of SR, CFTR, and Cl−/HCO3− AE2 and ablated secretin-stimulated biliary secretion in these cells. Conclusion Local modulation of melatonin synthesis may be important for the management of the balance between biliary proliferation/damage that is typical of cholangiopathies. PMID:23080076

  20. Functional Consequences and Structural Interpretation of Mutations of Human Choline Acetyltransferase

    PubMed Central

    Shen, Xin-Ming; Crawford, Thomas O.; Brengman, Joan; Acsadi, Gyula; Iannaconne, Susan; Karaca, Emin; Khoury, Chaouky; Mah, Jean K.; Edvardson, Shimon; Bajzer, Zeljko; Rodgers, David; Engel, Andrew G.

    2011-01-01

    Choline acetyltransferase (ChAT; EC 2.3.1.6) catalyzes synthesis of acetylcholine from acetyl-CoA and choline in cholinergic neurons. Mutations in CHAT (MIM # 118490) cause potentially lethal congenital myasthenic syndromes associated with episodic apnea (ChAT-CMS) (MIM # 254210). Here we analyze the functional consequences of 12 missense and 1 nonsense mutations of CHAT in 11 patients. Nine of the mutations are novel. We examine expression of the recombinant missense mutants in Bosc 23 cells, determine their kinetic properties and thermal stability, and interpret the functional effects of 11 mutations in the context of the atomic structural model of human ChAT. Five mutations (p.Trp421Ser, p.Ser498Pro, p.Thr553Asn, p.Ala557Thr, p.Ser572Trp) reduce enzyme expression to <50% of wild-type. Mutations with severe kinetic effects are located in the active-site tunnel (p.Met202Arg, p.Thr553Asn and p.Ala557Thr) or adjacent to the substrate binding site (p.Ser572Trp), or exert their effect allosterically (p.Trp421Ser and p.Ile689Ser). Two mutations with milder kinetic effects (p.Val136Met, p.Ala235Thr) are also predicted to act allosterically. One mutation (p.Thr608Asn) below the nucleotide binding site of CoA enhances dissociation of AcCoA from the enzyme-substrate complex. Two mutations introducing a proline residue into an α-helix (p.Ser498Pro and p.Ser704Pro) impair the thermal stability of ChAT. PMID:21786365

  1. Differential expression of histone deacetylase and acetyltransferase genes in gastric cancer and their modulation by trichostatin A.

    PubMed

    Wisnieski, Fernanda; Calcagno, Danielle Queiroz; Leal, Mariana Ferreira; Chen, Elizabeth Suchi; Gigek, Carolina Oliveira; Santos, Leonardo Caires; Pontes, Thaís Brilhante; Rasmussen, Lucas Trevizani; Payão, Spencer Luiz Marques; Assumpção, Paulo Pimentel; Lourenço, Laércio Gomes; Demachki, Sâmia; Artigiani, Ricardo; Burbano, Rommel Rodríguez; Smith, Marília Cardoso

    2014-07-01

    Gastric cancer is still the second leading cause of cancer-related death worldwide, even though its incidence and mortality have declined over the recent few decades. Epigenetic control using histone deacetylase inhibitors, such as trichostatin A (TSA), is a promising cancer therapy. This study aimed to assess the messenger RNA (mRNA) levels of three histone deacetylases (HDAC1, HDAC2, and HDAC3), two histone acetyltransferases (GCN5 and PCAF), and two possible targets of these histone modifiers (MYC and CDKN1A) in 50 matched pairs of gastric tumors and corresponding adjacent nontumors samples from patients with gastric adenocarcinoma, as well as their correlations and their possible associations with clinicopathological features. Additionally, we evaluated whether these genes are sensitive to TSA in gastric cancer cell lines. Our results demonstrated downregulation of HDAC1, PCAF, and CDKN1A in gastric tumors compared with adjacent nontumors (P < 0.05). On the other hand, upregulation of HDAC2, GCN5, and MYC was observed in gastric tumors compared with adjacent nontumors (P < 0.05). The mRNA level of MYC was correlated to HDAC3 and GCN5 (P < 0.05), whereas CDKN1A was correlated to HDAC1 and GCN5 (P < 0.05 and P < 0.01, respectively). In addition, the reduced expression of PCAF was associated with intestinal-type gastric cancer (P = 0.03) and TNM stages I/II (P = 0.01). The increased expression of GCN5 was associated with advanced stage gastric cancer (P = 0.02) and tumor invasion (P = 0.03). The gastric cell lines treated with TSA showed different patterns of histone deacetylase and acetyltransferase mRNA expression, downregulation of MYC, and upregulation of CDKN1A. Our findings suggest that alteration of histone modifier genes play an important role in gastric carcinogenesis, contributing to MYC and CDKN1A deregulation. In addition, all genes studied here are modulated by TSA, although this modulation appears to be dependent of the genetic background of the cell

  2. Elevated arylalkylamine-N-acetyltransferase (AA-NAT) gene expression in medial habenular and suprachiasmatic nuclei of hibernating ground squirrels.

    PubMed

    Yu, Erik Z; Hallenbeck, John M; Cai, Decheng; McCarron, Richard M

    2002-06-15

    Hibernation, an adaptive response for energy conservation in mammals, involves a variety of physiological changes. Melatonin is linked with the regulation of core body temperature and intervenes in generating circadian cycles; its role in seasonal (circannual) rhythms of hibernation is explored here. Melatonin is primarily produced in the pineal gland. Since arylalkylamine-N-acetyltransferase (AA-NAT) is the rate-limiting enzyme for synthesizing melatonin, AA-NAT gene expression was investigated to assess the possible role of melatonin in hibernation. The findings presented here utilized combined in situ hybridization and immunohistochemistry methodologies to evaluate the AA-NAT mRNA expression in brains of both hibernating and non-hibernating ground squirrels. Brains were examined for the expression of AA-NAT mRNA using a oligonucleotide AA-NAT probe; antibody against neurofilament-70 (NF-70) was used as a neuronal marker. All hibernating animals expressed significantly (P<0.01) elevated levels of AA-NAT mRNA in both the epithalamic medial habenular nuclei (MHb) area and the hypothalamic suprachiasmatic nuclei (SCN), which is also known as the master biologic clock. These findings represent the first demonstration of the expression of mRNA encoding for AA-NAT in the extra-pineal (i.e. SCN and MHb) sites of thirteen-lined ground squirrels and indicate that the habenular nucleus may be an important supplementary location for melatonin biosynthesis. The data presented here indicate that AA-NAT gene is one of the few specific genes up-regulated during hibernation and suggest that elevation of its expression in SCN and MHb may play an essential role in the generation and maintenance of hibernation. PMID:12191489

  3. G9a-mediated methylation of ERα links the PHF20/MOF histone acetyltransferase complex to hormonal gene expression

    PubMed Central

    Zhang, Xi; Peng, Danni; Xi, Yuanxin; Yuan, Chao; Sagum, Cari A.; Klein, Brianna J.; Tanaka, Kaori; Wen, Hong; Kutateladze, Tatiana G.; Li, Wei; Bedford, Mark T.; Shi, Xiaobing

    2016-01-01

    The euchromatin histone methyltransferase 2 (also known as G9a) methylates histone H3K9 to repress gene expression, but it also acts as a coactivator for some nuclear receptors. The molecular mechanisms underlying this activation remain elusive. Here we show that G9a functions as a coactivator of the endogenous oestrogen receptor α (ERα) in breast cancer cells in a histone methylation-independent manner. G9a dimethylates ERα at K235 both in vitro and in cells. Dimethylation of ERαK235 is recognized by the Tudor domain of PHF20, which recruits the MOF histone acetyltransferase (HAT) complex to ERα target gene promoters to deposit histone H4K16 acetylation promoting active transcription. Together, our data suggest the molecular mechanism by which G9a functions as an ERα coactivator. Along with the PHF20/MOF complex, G9a links the crosstalk between ERα methylation and histone acetylation that governs the epigenetic regulation of hormonal gene expression. PMID:26960573

  4. Co-expression of G2-EPSPS and glyphosate acetyltransferase GAT genes conferring high tolerance to glyphosate in soybean

    PubMed Central

    Guo, Bingfu; Guo, Yong; Hong, Huilong; Jin, Longguo; Zhang, Lijuan; Chang, Ru-Zhen; Lu, Wei; Lin, Min; Qiu, Li-Juan

    2015-01-01

    Glyphosate is a widely used non-selective herbicide with broad spectrum of weed control around the world. At present, most of the commercial glyphosate tolerant soybeans utilize glyphosate tolerant gene CP4-EPSPS or glyphosate acetyltransferase gene GAT separately. In this study, both glyphosate tolerant gene G2-EPSPS and glyphosate degraded gene GAT were co-transferred into soybean and transgenic plants showed high tolerance to glyphosate. Molecular analysis including PCR, Sothern blot, qRT-PCR, and Western blot revealed that target genes have been integrated into genome and expressed effectively at both mRNA and protein levels. Furthermore, the glyphosate tolerance analysis showed that no typical symptom was observed when compared with a glyphosate tolerant line HJ06-698 derived from GR1 transgenic soybean even at fourfold labeled rate of Roundup. Chlorophyll and shikimic acid content analysis of transgenic plant also revealed that these two indexes were not significantly altered after glyphosate application. These results indicated that co-expression of G2-EPSPS and GAT conferred high tolerance to the herbicide glyphosate in soybean. Therefore, combination of tolerant and degraded genes provides a new strategy for developing glyphosate tolerant transgenic crops. PMID:26528311

  5. Over-expression, purification, and characterization of recombinant human arylamine N-acetyltransferase 1.

    PubMed

    Wang, Haiqing; Vath, Gregory M; Kawamura, Akane; Bates, Caleb A; Sim, Edith; Hanna, Patrick E; Wagner, Carston R

    2005-02-01

    Human arylamine N-acetyltransferase 1 (NAT1) has been overexpressed in E. coli as a mutant dihydrofolic acid reductase (DHFR) fusion protein with a thrombin sensitive linker. An initial DEAE anion-exchange chromatography resulted in partial purification of the fusion protein. The fusion protein was cleaved with thrombin, and human rNAT1 was purified with a second DEAE column. A total of 8 mg of human rNAT1 from 2 1 of cell culture was purified to homogeneity with this methodology. Arylamine substrate specificities were determined for human rNATI and hamster rNAT2. With both NATs, the second order rate constants (k(cat)/ Kmb) for p-aminobenzoic acid (PABA) and 2-aminofluorene (2-AF) were several thousand-fold higher than those for procainamide (PA), consistent with the expected substrate specificities of the enzymes. However, p-aminosalicylic acid (PAS), previously reported to be a human NAT1 and hamster NAT2 selective substrate, exhibits 20-fold higher specificity for hamster rNAT2 (k(cat)/Kmb 3410 microM(-1) s(-1)) than for human rNAT1 (k(cat)/Kmb 169.4 microM(-1) s(-1)). p-aminobenzoyl-glutamic acid (pABglu) was acetylated 10-fold more efficiently by human rNAT1 than by hamster rNAT2. Inhibition studies of human rNAT1 and hamster rNAT2 revealed that folic acid and methotrexate (MTX) are competitive inhibitors of both the unacetylated and acetylated forms of the enzymes, with K(I) values in 50 - 300 micro range. Dihydrofolic acid (DHF) was a much poorer inhibitor of human rNAT1 than of hamster rNAT2. The combined results demonstrate that human rNAT1 and hamster rNAT2 have similar but distinct kinetic properties with certain substrates, and suggest that folic acid, at least in the non-polyglutamate form, may not have an effect on human NAT1 activity in vivo. PMID:16003948

  6. Co-expression of GAD67 and choline acetyltransferase reveals a novel neuronal phenotype in the mouse medulla oblongata.

    PubMed

    Gotts, Jittima; Atkinson, Lucy; Edwards, Ian J; Yanagawa, Yuchio; Deuchars, Susan A; Deuchars, Jim

    2015-12-01

    GABAergic and cholinergic systems play an important part in autonomic pathways. To determine the distribution of the enzymes responsible for the production of GABA and acetylcholine in areas involved in autonomic control in the mouse brainstem, we used a transgenic mouse expressing green fluorescent protein (GFP) in glutamate decarboxylase 67 (GAD67) neurones, combined with choline acetyl transferase (ChAT) immunohistochemistry. ChAT-immunoreactive (IR) and GAD67-GFP containing neurones were observed throughout the brainstem. A small number of cells contained both ChAT-IR and GAD67-GFP. Such double labelled cells were observed in the NTS (predominantly in the intermediate and central subnuclei), the area postrema, reticular formation and lateral paragigantocellular nucleus. All ChAT-IR neurones in the area postrema contained GAD67-GFP. Double labelled neurones were not observed in the dorsal vagal motor nucleus, nucleus ambiguus or hypoglossal nucleus. Double labelled ChAT-IR/GAD67-GFP cells in the NTS did not contain neuronal nitric oxide synthase (nNOS) immunoreactivity, whereas those in the reticular formation and lateral paragigantocellular nucleus did. The function of these small populations of double labelled cells is currently unknown, however their location suggests a potential role in integrating signals involved in oromotor behaviours. PMID:26015156

  7. The histone acetyltransferase p300 regulates the expression of pluripotency factors and odontogenic differentiation of human dental pulp cells.

    PubMed

    Wang, Tong; Liu, Huijuan; Ning, Yanyang; Xu, Qiong

    2014-01-01

    p300 is a well-known histone acetyltransferase (HAT) and coactivator that plays vital roles in many physiological processes. Despite extensive research on the involvement of p300 in the regulation of transcription in numerous cell lines, the roles of this protein in regulating pluripotency genes and odontogenic differentiation in human dental pulp cells (HDPCs) are poorly understood. To address this issue, we investigated the expression of OCT4, NANOG and SOX2 and the proliferation and odontogenic differentiation capacity of HDPCs following p300 overexpression. We found that p300 overexpression did not overtly affect the ability of HDPCs to proliferate. The overexpression of p300 upregulated the promoter activity and the mRNA and protein expression of NANOG and SOX2. The HAT activity of p300 appeared to partially mediate the regulation of these factors; indeed, when a mutant form of p300 lacking the HAT domain was overexpressed, the promoter activity and expression of NANOG and SOX2 decreased relative to p300 overexpression but was greater than in the control. Furthermore, we demonstrated that the mRNA levels of the odontogenic marker genes dentine matrix protein-1 (DMP-1), dentin sialophosphoprotein (DSPP), dentin sialoprotein (DSP), osteopontin (OPN) and osteocalcin (OCN) were significantly decreased in HDPCs overexpressing p300 cultured under normal culture conditions and increased in HDPCs inducted to undergo odontogenic differentiation. This finding was further confirmed by measuring levels of alkaline phosphatase (ALP) activity and assessing the formation of mineralized nodules. The HAT activity of p300 had no significant effect on odontogenic differentiation. p300 was recruited to the promoter regions of OCN and DSPP and might be acting as a coactivator to increase the acetylation of lysine 9 of histone H3 of OCN and DSPP. Collectively, our results show that p300 plays an important role in regulating the expression of key pluripotency genes in HDPCs and

  8. Method to produce acetyldiacylglycerols (ac-TAGs) by expression of an acetyltransferase gene isolated from Euonymus alatus (burning bush)

    DOEpatents

    Durrett, Timothy; Ohlrogge, John; Pollard, Michael

    2016-05-03

    The present invention relates to novel diacylglycerol acyltransferase genes and proteins, and methods of their use. In particular, the invention describes genes encoding proteins having diacylglycerol acetyltransferase activity, specifically for transferring an acetyl group to a diacylglycerol substrate to form acetyl-Triacylglycerols (ac-TAGS), for example, a 3-acetyl-1,2-diacyl-sn-glycerol. The present invention encompasses both native and recombinant wild-type forms of the transferase, as well as mutants and variant forms. The present invention also relates to methods of using novel diacylglycerol acyltransferase genes and proteins, including their expression in transgenic organisms at commercially viable levels, for increasing production of 3-acetyl-1,2-diacyl-sn-glycerols in plant oils and altering the composition of oils produced by microorganisms, such as yeast, by increasing ac-TAG production. Additionally, oils produced by methods of the present inventions comprising genes and proteins are contemplated for use as biodiesel fuel, in polymer production and as naturally produced food oils with reduced calories.

  9. Modified Checklist for Autism in Toddlers (M-CHAT) Screening at 18 Months of Age Predicts Concurrent Understanding of Desires, Word Learning and Expressive Vocabulary

    ERIC Educational Resources Information Center

    Wright, Kristyn; Poulin-Dubois, Diane

    2012-01-01

    The Modified Checklist for Autism in Toddlers (M-CHAT) is a 23-item questionnaire used in primary screening of Autism Spectrum Disorder (ASD). The current studies examine the concurrent validity of the M-CHAT in its ability to predict 18-month-olds' performance on theory of mind and word learning tasks. In Experiment 1, infants' understanding of…

  10. Spatial Memory Consolidation is Associated with Induction of Several Lysine-Acetyltransferase (Histone Acetyltransferase) Expression Levels and H2B/H4 Acetylation-Dependent Transcriptional Events in the Rat Hippocampus

    PubMed Central

    Bousiges, Olivier; Vasconcelos, Anne Pereira de; Neidl, Romain; Cosquer, Brigitte; Herbeaux, Karine; Panteleeva, Irina; Loeffler, Jean-Philippe; Cassel, Jean-Christophe; Boutillier, Anne-Laurence

    2010-01-01

    Numerous genetic studies have shown that the CREB-binding protein (CBP) is an essential component of long-term memory formation, through its histone acetyltransferase (HAT) function. E1A-binding protein p300 and p300/CBP-associated factor (PCAF) have also recently been involved in memory formation. By contrast, only a few studies have reported on acetylation modifications during memory formation, and it remains unclear as to how the system is regulated during this dynamic phase. We investigated acetylation-dependent events and the expression profiles of these HATs during a hippocampus-dependent task taxing spatial reference memory in the Morris water maze. We found a specific increase in H2B and H4 acetylation in the rat dorsal hippocampus, while spatial memory was being consolidated. This increase correlated with the degree of specific acetylated histones enrichment on some memory/plasticity-related gene promoters. Overall, a global increase in HAT activity was measured during this memory consolidation phase, together with a global increase of CBP, p300, and PCAF expression. Interestingly, these regulations were altered in a model of hippocampal denervation disrupting spatial memory consolidation, making it impossible for the hippocampus to recruit the CBP pathway (CBP regulation and acetylated-H2B-dependent transcription). CBP has long been thought to be present in limited concentrations in the cells. These results show, for the first time, that CBP, p300, and PCAF are dynamically modulated during the establishment of a spatial memory and are likely to contribute to the induction of a specific epigenetic tagging of the genome for hippocampus-dependent (spatial) memory consolidation. These findings suggest the use of HAT-activating molecules in new therapeutic strategies of pathological aging, Alzheimer's disease, and other neurodegenerative disorders. PMID:20811339

  11. The Importance of Nonverbal Elements in Online Chat

    ERIC Educational Resources Information Center

    Gajadhar, Joan; Green, John

    2005-01-01

    Communication is often not so much what people write or say but how they write and often what they do not say. Thus, meaning in real-world chat messages depends not only on the words they use but also on how they express meaning through nonverbal cues. Online chat is simple, direct, and unrestrained. While it contains many of the elements of…

  12. Expression Levels of the Yeast Alcohol Acetyltransferase Genes ATF1, Lg-ATF1, and ATF2 Control the Formation of a Broad Range of Volatile Esters

    PubMed Central

    Verstrepen, Kevin J.; Van Laere, Stijn D. M.; Vanderhaegen, Bart M. P.; Derdelinckx, Guy; Dufour, Jean-Pierre; Pretorius, Isak S.; Winderickx, Joris; Thevelein, Johan M.; Delvaux, Freddy R.

    2003-01-01

    Volatile aroma-active esters are responsible for the fruity character of fermented alcoholic beverages such as beer and wine. Esters are produced by fermenting yeast cells in an enzyme-catalyzed intracellular reaction. In order to investigate and compare the roles of the known Saccharomyces cerevisiae alcohol acetyltransferases, Atf1p, Atf2p and Lg-Atf1p, in volatile ester production, the respective genes were either deleted or overexpressed in a laboratory strain and a commercial brewing strain. Subsequently, the ester formation of the transformants was monitored by headspace gas chromatography and gas chromatography combined with mass spectroscopy (GC-MS). Analysis of the fermentation products confirmed that the expression levels of ATF1 and ATF2 greatly affect the production of ethyl acetate and isoamyl acetate. GC-MS analysis revealed that Atf1p and Atf2p are also responsible for the formation of a broad range of less volatile esters, such as propyl acetate, isobutyl acetate, pentyl acetate, hexyl acetate, heptyl acetate, octyl acetate, and phenyl ethyl acetate. With respect to the esters analyzed in this study, Atf2p seemed to play only a minor role compared to Atf1p. The atf1Δ atf2Δ double deletion strain did not form any isoamyl acetate, showing that together, Atf1p and Atf2p are responsible for the total cellular isoamyl alcohol acetyltransferase activity. However, the double deletion strain still produced considerable amounts of certain other esters, such as ethyl acetate (50% of the wild-type strain), propyl acetate (50%), and isobutyl acetate (40%), which provides evidence for the existence of additional, as-yet-unknown ester synthases in the yeast proteome. Interestingly, overexpression of different alleles of ATF1 and ATF2 led to different ester production rates, indicating that differences in the aroma profiles of yeast strains may be partially due to mutations in their ATF genes. PMID:12957907

  13. A human parvovirus, adeno-associated virus, as a eucaryotic vector: Transient expression and encapsidation of the procaryotic gene for chloramphenicol acetyltransferase

    SciTech Connect

    Tratschin, J.D.; West, M.H.P.; Sandbank, T.; Carter, B.J.

    1984-10-01

    The authors have used the defective human parvovirus adeno-associated virus (AAV) as a novel eurocaryotic vector (parvector) for the expression of a foreign gene in human cells. The recombinant, pAV2, contains the AAV genome in a pBR322-derived bacterial plasmid. When pAV2 is transfected into human cells together with helper adenovirus particles, the AAV genome is rescued from the recombinant plasmid and replicated to produce infectious AAV particles at high efficiency. To create a vector, we inserted a procaryotic sequence coding for chloramphenicol acetyltransferase (CAT) into derivatives of pAV2 following either of the AAV promoters p/sub 40/ (pAVHiCAT) and p/sub 19/ (pAVBcCAT). When transfected into human 293 cells or HeLa cells, pAVHiCAT expressed CAT activity in the absence of adenovirus. In the presence of adenovirus, this vector produced increased amounts of CAT activity and the recombinant AAV-CAT genome was replicated. In 293 cells, pAVBcCAT expressed a similar amount of CAT activity in the absence or presence of adenovirus and the recombinant AAV-CAT genome was not replicated. In HeLa cells, pAVBcCAT expressed low levels of CAT activity, but this level was elevated by coinfection with adenovirus particles or by cotransfection with a plasmid which expressed the adenovirus early region 1A (E1A) product. The E1A product is a transcriptional activator and is expressed in 293 cells. Thus, expression from two AAV promoters is differentially regulated: expression from p/sub 19/ is increased by E1A, whereas p/sub 40/ yields high levels of constitutive expression in the absence of E1A. Both AAV vectors were packaged into AAV particles by complementation with wild-type AAV and yielded CAT activity when subsequently infected into cells in the presence of adenovirus.

  14. Anacardic acid, a histone acetyltransferase inhibitor, modulates LPS-induced IL-8 expression in a human alveolar epithelial cell line A549

    PubMed Central

    Takizawa, Hajime

    2013-01-01

    Objective and design: The histone acetylation processes, which are believed to play a critical role in the regulation of many inflammatory genes, are reversible and regulated by histone acetyltransferases (HATs), which promote acetylation, and histone deacetylases (HDACs), which promote deacetylation. We studied the effects of lipopolysaccharide (LPS) on histone acetylation and its role in the regulation of interleukin (IL)-8 expression.  Material: A human alveolar epithelial cell line A549 was used in vitro. Methods: Histone H4 acetylation at the IL-8 promoter region was assessed by a chromatin immunoprecipitation (ChIP) assay. The expression and production of IL-8 were evaluated by quantitative polymerase chain reaction and specific immunoassay. Effects of a HDAC inhibitor, trichostatin A (TSA), and a HAT inhibitor, anacardic acid, were assessed.  Results: Escherichia coli-derived LPS showed a dose- and time-dependent stimulatory effect on IL-8 protein production and mRNA expression in A549 cells in vitro. LPS showed a significant stimulatory effect on histone H4 acetylation at the IL-8 promoter region by ChIP assay. Pretreatment with TSA showed a dose-dependent stimulatory effect on IL-8 release from A549 cells as compared to LPS alone. Conversely, pretreatment with anacardic acid inhibited IL-8 production and expression in A549 cells.  Conclusion: These data suggest that LPS-mediated proinflammatory responses in the lungs might be modulated via changing chromatin remodeling by HAT inhibition. PMID:24627774

  15. A rice chloroplast transit peptide sequence does not alter the cytoplasmic localization of sheep serotonin N-acetyltransferase expressed in transgenic rice plants.

    PubMed

    Byeon, Yeong; Lee, Hyoung Yool; Lee, Kyungjin; Back, Kyoungwhan

    2014-09-01

    Ectopic overexpression of melatonin biosynthetic genes of animal origin has been used to generate melatonin-rich transgenic plants to examine the functional roles of melatonin in plants. However, the subcellular localization of these proteins expressed in the transgenic plants remains unknown. We studied the localization of sheep (Ovis aries) serotonin N-acetyltransferase (OaSNAT) and a translational fusion of a rice SNAT transit peptide to OaSNAT (TS:OaSNAT) in plants. Laser confocal microscopy analysis revealed that both OaSNAT and TS:OaSNAT proteins were localized to the cytoplasm even with the addition of the transit sequence to OaSNAT. Transgenic rice plants overexpressing the TS:OaSNAT fusion transgene exhibited high SNAT enzyme activity relative to untransformed wild-type plants, but lower activity than transgenic rice plants expressing the wild-type OaSNAT gene. Melatonin levels in both types of transgenic rice plant corresponded well with SNAT enzyme activity levels. The TS:OaSNAT transgenic lines exhibited increased seminal root growth relative to wild-type plants, but less than in the OaSNAT transgenic lines, confirming that melatonin promotes root growth. Seed-specific OaSNAT expression under the control of a rice prolamin promoter did not confer high levels of melatonin production in transgenic rice seeds compared with seeds from transgenic plants expressing OaSNAT under the control of the constitutive maize ubiquitin promoter. PMID:24920304

  16. Chat Reference. SPEC Kit.

    ERIC Educational Resources Information Center

    Ronan, Jana, Comp.; Turner, Carol, Comp.

    2002-01-01

    This SPEC (Systems and Procedures Exchange Center) Kit presents the results of a survey of Association of Research Libraries (ARL) member libraries designed to gather data on chat reference service. A total of 66 of 124 ARL member libraries responded to the survey. A copy of the questionnaire with tabulated results is presented. Representative…

  17. Internet Relay Chat.

    ERIC Educational Resources Information Center

    Simpson, Carol

    2000-01-01

    Describes Internet Relay Chats (IRCs), electronic conversations over the Internet that allow multiple users to write messages, and their applications to educational settings such as teacher collaboration and conversations between classes. Explains hardware and software requirements, IRC organization into nets and channels, and benefits and…

  18. Valproic acid exposure decreases Cbp/p300 protein expression and histone acetyltransferase activity in P19 cells.

    PubMed

    Lamparter, Christina L; Winn, Louise M

    2016-09-01

    The teratogenicity of the antiepileptic drug valproic acid (VPA) is well established and its inhibition of histone deacetylases (HDAC) is proposed as an initiating factor. Recently, VPA-mediated HDAC inhibition was demonstrated to involve transcriptional downregulation of histone acetyltransferases (HATs), which was proposed to compensate for the increased acetylation resulting from HDAC inhibition. Cbp and p300 are HATs required for embryonic development and deficiencies in either are associated with congenital malformations and embryolethality. The objective of the present study was to characterize Cbp/p300 following VPA exposure in P19 cells. Consistent with previous studies, exposure to 5mM VPA over 24h induced a moderate decrease in Cbp/p300 mRNA, which preceded a strong decrease in total cellular protein mediated by ubiquitin-proteasome degradation. Nuclear Cbp/p300 protein was also decreased following VPA exposure, although to a lesser extent. Total cellular and nuclear p300 HAT activity was reduced proportionately to p300 protein levels, however while total cellular HAT activity also decreased, nuclear HAT activity was unaffected. Using the Cbp/p300 HAT inhibitor C646, we demonstrated that HAT inhibition similarly affected many of the same endpoints as VPA, including increased reactive oxygen species and caspase-3 cleavage, the latter of which could be attenuated by pre-treatment with the antioxidant catalase. C646 exposure also decreased NF-κB/p65 protein, which was not due to reduced mRNA and was not attenuated with catalase pre-treatment. This study provides support for an adaptive HAT response following VPA exposure and suggests that reduced Cbp/p300 HAT activity could contribute to VPA-mediated alterations. PMID:27381264

  19. Effects of chronic social defeat stress on behaviour, endoplasmic reticulum proteins and choline acetyltransferase in adolescent mice.

    PubMed

    Huang, Guang-Biao; Zhao, Tong; Muna, Sushma Shrestha; Bagalkot, Tarique Rajasaheb; Jin, Hong-Mei; Chae, Han-Jung; Chung, Young-Chul

    2013-08-01

    The present study investigated the effects of social defeat stress on the behaviours and expressions of 78-kDa glucose-regulated protein (Grp78), CCAAT/enhancer-binding protein (C/EBP) homologous protein (CHOP) and choline acetyltransferase (Chat) in the brains of adolescent mice. Adolescent male C57BL/6J mice were divided into two groups (susceptible and unsusceptible) after 10 d social defeat stress. In expt 1, behavioural tests were conducted and brains were processed for Western blotting on day 21 after stress. In expt 2, social avoidance tests were conducted and brains were subsequently processed for Western blotting on day 12 after stress. Chronic social defeat stress produced more pronounced depression-like behaviours such as decreased locomotion and social interaction, increased anxiety-like behaviours and immobility, and impaired memory performance in susceptible mice. Moreover, susceptible mice showed greater expression of Grp78 and CHOP in the amygdala (Amyg) on days 12 and 21 compared with the other groups. Susceptible and unsusceptible groups showed significant increases in Grp78 and CHOP expression in the prefrontal cortex (PFC) and hippocampus (Hipp) on day 12 compared with the control group; this persisted until day 21. The levels of Chat measured on days 12 and 21 were significantly lower in the PFC, Amyg and Hipp of all defeated mice compared with controls. The findings of the behavioural tests indicate that chronic social defeat in adolescents produces anxiety-like behaviours, social withdrawal, despair-like behaviours and cognitive impairment. The Grp78, CHOP and Chat results suggest that the selective response of endoplasmic reticulum stress proteins in the Amyg plays an important role in the vulnerability-stress model of depression. PMID:23442729

  20. Spermine analogue-regulated expression of spermidine/spermine N1-acetyltransferase and its effects on depletion of intracellular polyamine pools in mouse fetal fibroblasts.

    PubMed

    Uimari, Anne; Keinänen, Tuomo A; Karppinen, Anne; Woster, Patrick; Uimari, Pekka; Jänne, Juhani; Alhonen, Leena

    2009-08-15

    SSAT (Spermidine/spermine N1-acetyltransferase, also known as SAT1), the key enzyme in the catabolism of polyamines, is turned over rapidly and there is only a low amount present in the cell. In the present study, the regulation of SSAT by spermine analogues, the inducers of the enzyme, was studied in wild-type mouse fetal fibroblasts, expressing endogenous SSAT, and in the SSAT-deficient mouse fetal fibroblasts transiently expressing an SSAT-EGFP (enhanced green fluorescent protein) fusion gene. In both cell lines treatments with DENSpm (N(1),N(11)-diethylnorspermine), CPENSpm (N(1)-ethyl-N(11)-[(cyclopropyl)-methy]-4,8-diazaundecane) and CHENSpm (N(1)-ethyl-N(11)-[(cycloheptyl)methy]-4,8-diazaundecane) led to high, moderate or low induction of SSAT activity respectively. The level of activity detected correlated with the presence of SSAT and SSAT-EGFP proteins, the latter localizing both in the cytoplasm and nucleus. RT-PCR (reverse transcription-PCR) results suggested that the analogue-affected regulation of SSAT-EGFP expression occurred, mainly, after transcription. In wild-type cells, DENSpm increased the amount of SSAT mRNA, and both DENSpm and CHENSpm affected splicing of the SSAT pre-mRNA. Depleted intracellular spermidine and spermine levels inversely correlated with detected SSAT activity. Interestingly, the analogues also reduced polyamine levels in the SSAT-deficient cells expressing the EGFP control. The results from the present study show that the distinct SSAT regulation by different analogues involves regulatory actions at multiple levels, and that the spermine analogues, in addition to inducing SSAT, lower intracellular polyamine pools by SSAT-independent mechanisms. PMID:19473115

  1. Novel ligands of Choline Acetyltransferase designed by in silico molecular docking, hologram QSAR and lead optimization

    PubMed Central

    Kumar, Rajnish; Långström, Bengt; Darreh-Shori, Taher

    2016-01-01

    Recent reports have brought back the acetylcholine synthesizing enzyme, choline acetyltransferase in the mainstream research in dementia and the cholinergic anti-inflammatory pathway. Here we report, a specific strategy for the design of novel ChAT ligands based on molecular docking, Hologram Quantitative Structure Activity Relationship (HQSAR) and lead optimization. Molecular docking was performed on a series of ChAT inhibitors to decipher the molecular fingerprint of their interaction with the active site of ChAT. Then robust statistical fragment HQSAR models were developed. A library of novel ligands was generated based on the pharmacophoric and shape similarity scoring function, and evaluated in silico for their molecular interactions with ChAT. Ten of the top scoring invented compounds are reported here. We confirmed the activity of α-NETA, the only commercially available ChAT inhibitor, and one of the seed compounds in our model, using a new simple colorimetric ChAT assay (IC50 ~ 88 nM). In contrast, α-NETA exhibited an IC50 of ~30 μM for the ACh-degrading cholinesterases. In conclusion, the overall results may provide useful insight for discovering novel ChAT ligands and potential positron emission tomography tracers as in vivo functional biomarkers of the health of central cholinergic system in neurodegenerative disorders, such as Alzheimer’s disease. PMID:27507101

  2. Novel ligands of Choline Acetyltransferase designed by in silico molecular docking, hologram QSAR and lead optimization.

    PubMed

    Kumar, Rajnish; Långström, Bengt; Darreh-Shori, Taher

    2016-01-01

    Recent reports have brought back the acetylcholine synthesizing enzyme, choline acetyltransferase in the mainstream research in dementia and the cholinergic anti-inflammatory pathway. Here we report, a specific strategy for the design of novel ChAT ligands based on molecular docking, Hologram Quantitative Structure Activity Relationship (HQSAR) and lead optimization. Molecular docking was performed on a series of ChAT inhibitors to decipher the molecular fingerprint of their interaction with the active site of ChAT. Then robust statistical fragment HQSAR models were developed. A library of novel ligands was generated based on the pharmacophoric and shape similarity scoring function, and evaluated in silico for their molecular interactions with ChAT. Ten of the top scoring invented compounds are reported here. We confirmed the activity of α-NETA, the only commercially available ChAT inhibitor, and one of the seed compounds in our model, using a new simple colorimetric ChAT assay (IC50 ~ 88 nM). In contrast, α-NETA exhibited an IC50 of ~30 μM for the ACh-degrading cholinesterases. In conclusion, the overall results may provide useful insight for discovering novel ChAT ligands and potential positron emission tomography tracers as in vivo functional biomarkers of the health of central cholinergic system in neurodegenerative disorders, such as Alzheimer's disease. PMID:27507101

  3. Isoform-level brain expression profiling of the spermidine/spermine N1-Acetyltransferase1 (SAT1) gene in major depression and suicide

    PubMed Central

    Pantazatos, Spiro P.; Andrews, Stuart J.; Dunning-Broadbent, Jane; Pang, Jiuhong; Huang, Yung-yu; Arango, Victoria; Nagy, Peter L.; Mann, J. John

    2016-01-01

    Low brain expression of the spermidine/spermine N-1 acetyltransferase (SAT1) gene, the rate-limiting enzyme involved in catabolism of polyamines that mediate the polyamine stress response (PSR), has been reported in depressed suicides. However, it is unknown whether this effect is associated with depression or with suicide and whether all or only specific isoforms expressed by SAT1, such as the primary 171 amino acid protein-encoding transcript (SSAT), or an alternative splice variant (SSATX) that is involved in SAT1 regulated unproductive splicing and transcription (RUST), are involved. We applied next generation sequencing (RNA-seq) to assess gene-level, isoform-level, and exon-level SAT1 expression differences between healthy controls (HC, N = 29), DSM-IV major depressive disorder suicides (MDD-S, N = 21) and MDD non-suicides (MDD, N = 9) in the dorsal lateral prefrontal cortex (Brodmann Area 9, BA9) of medication-free individuals postmortem. Using small RNA-seq, we also examined miRNA species putatively involved in SAT1 post-transcriptional regulation. A DSM-IV diagnosis was made by structured interview. Toxicology and history ruled out recent psychotropic medication. At the gene-level, we found low SAT1 expression in both MDD-S (vs. HC, p = 0.002) and MDD (vs. HC, p = 0.002). At the isoform-level, reductions in MDD-S (vs. HC) were most pronounced in four transcripts including SSAT and SSATX, while reductions in MDD (vs. HC) were pronounced in three transcripts, one of which was reduced in MDD relative to MDD-S (all p < 0.1 FDR corrected). We did not observe evidence for differential exon-usage (i.e. splicing) nor differences in miRNA expression. Results replicate the finding of low SAT1 brain expression in depressed suicides in an independent sample and implicate low SAT1 brain expression in MDD independent of suicide. Low expressions of both SSAT and SATX isoforms suggest that shared transcriptional mechanisms involved in RUST may account for low SAT1 brain

  4. Promotion of Cell Viability and Histone Gene Expression by the Acetyltransferase Gcn5 and the Protein Phosphatase PP2A in Saccharomyces cerevisiae.

    PubMed

    Petty, Emily L; Lafon, Anne; Tomlinson, Shannon L; Mendelsohn, Bryce A; Pillus, Lorraine

    2016-08-01

    Histone modifications direct chromatin-templated events in the genome and regulate access to DNA sequence information. There are multiple types of modifications, and a common feature is their dynamic nature. An essential step for understanding their regulation, therefore, lies in characterizing the enzymes responsible for adding and removing histone modifications. Starting with a dosage-suppressor screen in Saccharomyces cerevisiae, we have discovered a functional interaction between the acetyltransferase Gcn5 and the protein phosphatase 2A (PP2A) complex, two factors that regulate post-translational modifications. We find that RTS1, one of two genes encoding PP2A regulatory subunits, is a robust and specific high-copy suppressor of temperature sensitivity of gcn5∆ and a subset of other gcn5∆ phenotypes. Conversely, loss of both PP2A(Rts1) and Gcn5 function in the SAGA and SLIK/SALSA complexes is lethal. RTS1 does not restore global transcriptional defects in gcn5∆; however, histone gene expression is restored, suggesting that the mechanism of RTS1 rescue includes restoration of specific cell cycle transcripts. Pointing to new mechanisms of acetylation-phosphorylation cross-talk, RTS1 high-copy rescue of gcn5∆ growth requires two residues of H2B that are phosphorylated in human cells. These data highlight the potential significance of dynamic phosphorylation and dephosphorylation of these deeply conserved histone residues for cell viability. PMID:27317677

  5. RNAi-mediated knock-down of arylamine N-acetyltransferase-1 expression induces E-cadherin up-regulation and cell-cell contact growth inhibition.

    PubMed

    Tiang, Jacky M; Butcher, Neville J; Cullinane, Carleen; Humbert, Patrick O; Minchin, Rodney F

    2011-01-01

    Arylamine N-acetyltransferase-1 (NAT1) is an enzyme that catalyzes the biotransformation of arylamine and hydrazine substrates. It also has a role in the catabolism of the folate metabolite p-aminobenzoyl glutamate. Recent bioinformatics studies have correlated NAT1 expression with various cancer subtypes. However, a direct role for NAT1 in cell biology has not been established. In this study, we have knocked down NAT1 in the colon adenocarcinoma cell-line HT-29 and found a marked change in cell morphology that was accompanied by an increase in cell-cell contact growth inhibition and a loss of cell viability at confluence. NAT1 knock-down also led to attenuation in anchorage independent growth in soft agar. Loss of NAT1 led to the up-regulation of E-cadherin mRNA and protein levels. This change in E-cadherin was not attributed to RNAi off-target effects and was also observed in the prostate cancer cell-line 22Rv1. In vivo, NAT1 knock-down cells grew with a longer doubling time compared to cells stably transfected with a scrambled RNAi or to parental HT-29 cells. This study has shown that NAT1 affects cell growth and morphology. In addition, it suggests that NAT1 may be a novel drug target for cancer therapeutics. PMID:21347396

  6. Substrate Binding and Catalytic Mechanism of Human Choline Acetyltransferase

    SciTech Connect

    Kim,A.; Rylett, J.; Shilton, B.

    2006-01-01

    Choline acetyltransferase (ChAT) catalyzes the synthesis of the neurotransmitter acetylcholine from choline and acetyl-CoA, and its presence is a defining feature of cholinergic neurons. We report the structure of human ChAT to a resolution of 2.2 {angstrom} along with structures for binary complexes of ChAT with choline, CoA, and a nonhydrolyzable acetyl-CoA analogue, S-(2-oxopropyl)-CoA. The ChAT-choline complex shows which features of choline are important for binding and explains how modifications of the choline trimethylammonium group can be tolerated by the enzyme. A detailed model of the ternary Michaelis complex fully supports the direct transfer of the acetyl group from acetyl-CoA to choline through a mechanism similar to that seen in the serine hydrolases for the formation of an acyl-enzyme intermediate. Domain movements accompany CoA binding, and a surface loop, which is disordered in the unliganded enzyme, becomes localized and binds directly to the phosphates of CoA, stabilizing the complex. Interactions between this surface loop and CoA may function to lower the K{sub M} for CoA and could be important for phosphorylation-dependent regulation of ChAT activity.

  7. Chatting in Paragraphs: Towards Academic Discourse in Foreign Language Chat

    ERIC Educational Resources Information Center

    Mendelson, Adam

    2012-01-01

    This paper presents a case study of an individual student's increasing approximation of academic discourse during a third-semester Spanish class that included chat-based instruction. During both chat-based activities and oral discussions in class, the student's language use became increasingly characterized by longer turns and the use of…

  8. Emotional persistence in online chatting communities

    NASA Astrophysics Data System (ADS)

    Garas, Antonios; Garcia, David; Skowron, Marcin; Schweitzer, Frank

    2012-05-01

    How do users behave in online chatrooms, where they instantaneously read and write posts? We analyzed about 2.5 million posts covering various topics in Internet relay channels, and found that user activity patterns follow known power-law and stretched exponential distributions, indicating that online chat activity is not different from other forms of communication. Analysing the emotional expressions (positive, negative, neutral) of users, we revealed a remarkable persistence both for individual users and channels. I.e. despite their anonymity, users tend to follow social norms in repeated interactions in online chats, which results in a specific emotional ``tone'' of the channels. We provide an agent-based model of emotional interaction, which recovers qualitatively both the activity patterns in chatrooms and the emotional persistence of users and channels. While our assumptions about agent's emotional expressions are rooted in psychology, the model allows to test different hypothesis regarding their emotional impact in online communication.

  9. Integrating CHAT and Action Research

    ERIC Educational Resources Information Center

    Wells, Gordon

    2011-01-01

    The question as to how action research (AR) is related to cultural-historical activity theory (CHAT) is not answerable in categorical terms. Both CHAT and AR have been variously interpreted and much depends on the individual biographies of those who pronounce on their relationship. The aim of this paper is to show how action research, conducted…

  10. Expression, essentiality, and a microtiter plate assay for mycobacterial GlmU, the bifunctional glucosamine-1-phosphate acetyltransferase and N-acetylglucosamine-1-phosphate uridyltransferase

    PubMed Central

    Zhang, Wenli; Jones, Victoria C.; Scherman, Michael S.; Mahapatra, Sebabrata; Crick, Dean; Bhamidi, Suresh; Xin, Yi; McNeil, Michael R.; Ma, Yufang

    2008-01-01

    UDP-N-acetyl-D-glucosamine (UDP-GlcNAc) is an essential precursor of peptidoglycan and the rhamnose-GlcNAc linker region of mycobacterial cell wall. In Mycobacterium tuberculosis H37Rv genome, Rv1018c shows strong homology to the GlmU protein involved in the formation of UDP-GlcNAc from other bacteria. GlmU is a bifunctional enzyme that catalyzes two sequential steps in UDP-GlcNAc biosynthesis. Glucosamine-1-phosphate acetyl transferase catalyzes the formation of N-acetylglucosamine-1-phosphate, and N-acetylglucosamine-1-phosphate uridylyltransferase catalyzes the formation of UDP-GlcNAc. Since inhibition of peptidoglycan synthesis often results in cell lysis, M. tuberculosis GlmU is a potential anti-tuberculosis drug target. In this study we cloned M. tuberculosis Rv1018c (glmU gene) and expressed soluble GlmU protein in E. coli BL21(DE3). Enzymatic assays showed that M. tuberculosis GlmU protein exhibits both glucosamine-1-phosphate acetyltransferase and N-acetylglucosamine-1-phosphate uridylyltransferase activities. We also investigated the effect on Mycobacterium smegmatis when the activity of GlmU is fully removed or reduced via a genetic approach. The results showed that activity of GlmU is required for growth of M. smegmatis as the bacteria did not grow in the absence of active GlmU enzyme. As the amount of functional GlmU enzyme was gradually reduced in a temperature shift experiment, the M. smegmatis cells became non-viable and their morphology changed from a normal rod shape to stubby-rounded morphology and in some cases they lysed. Finally a microtiter plate based assay for GlmU activity with an OD340 read out was developed. These studies therefore support the further development of M. tuberculosis GlmU enzyme as a target for new anti-tuberculosis drugs. PMID:18573680

  11. Comparative inhibition of chloramphenicol acetyltransferase gene expression by antisense oligonucleotide analogues having alkyl phosphotriester, methylphosphonate and phosphorothioate linkages.

    PubMed Central

    Marcus-Sekura, C J; Woerner, A M; Shinozuka, K; Zon, G; Quinnan, G V

    1987-01-01

    Several classes of oligonucleotide antisense compounds of sequence complementary to the start of the mRNA coding sequence for chloramphenicol acetyl transferase (CAT), including methylphosphonate, alkyltriester, and phosphorothioate analogues of DNA, have been compared to "normal" phosphodiester oligonucleotides for their ability to inhibit expression of plasmid-directed CAT gene activity in CV-1 cells. CAT gene expression was inhibited when transfection with plasmid DNA containing the gene for CAT coupled to simian virus 40 regulatory sequences (pSV2CAT) or the human immunodeficiency virus enhancer (pHIVCAT) was carried out in the presence of 30 microM concentrations of analogue. For the oligo-methylphosphonate analogue, inhibition was dependent on both oligomer concentration and chain length. Analogues with phosphodiester linkages that alternated with either methylphosphonate, ethyl phosphotriester, or isopropyl phosphotriester linkages were less effective inhibitors, in that order. The phosphorothioate analogue was about two-times more potent than the oligo-methylphosphonate, which was in turn approximately twice as potent as the normal oligonucleotide. Images PMID:3475677

  12. Resistance to glufosinate is proportional to phosphinothricin acetyltransferase expression and activity in LibertyLink® and WideStrike® Cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    LibertyLink® cotton cultivars are engineered for glufosinate resistance by overexpressing the bar gene that encodes phosphinothricin acetyltransferase (PAT), whereas the insect-resistant WideStrike® cultivars were obtained by using the similar pat gene as a selectable marker. The latter cultivars ca...

  13. Association between Fatigue and Autistic Symptoms in Children with Cri du Chat Syndrome

    ERIC Educational Resources Information Center

    Claro, Anthony; Cornish, Kim; Gruber, Reut

    2011-01-01

    In the current study, the authors examined whether the fatigue level of children diagnosed with cri du chat syndrome was associated with the expression of autistic symptoms. Sixty-nine children with cri du chat syndrome were compared with 47 children with moderate to severe intellectual disabilities who did not differ on intellectual severity.…

  14. Cri du Chat syndrome

    PubMed Central

    Cerruti Mainardi, Paola

    2006-01-01

    The Cri du Chat syndrome (CdCS) is a genetic disease resulting from a deletion of variable size occurring on the short arm of chromosome 5 (5p-). The incidence ranges from 1:15,000 to 1:50,000 live-born infants. The main clinical features are a high-pitched monochromatic cry, microcephaly, broad nasal bridge, epicanthal folds, micrognathia, abnormal dermatoglyphics, and severe psychomotor and mental retardation. Malformations, although not very frequent, may be present: cardiac, neurological and renal abnormalities, preauricular tags, syndactyly, hypospadias, and cryptorchidism. Molecular cytogenetic analysis has allowed a cytogenetic and phenotypic map of 5p to be defined, even if results from the studies reported up to now are not completely in agreement. Genotype-phenotype correlation studies showed a clinical and cytogenetic variability. The identification of phenotypic subsets associated with a specific size and type of deletion is of diagnostic and prognostic relevance. Specific growth and psychomotor development charts have been established. Two genes, Semaphorin F (SEMAF) and δ-catenin (CTNND2), which have been mapped to the "critical regions", are potentially involved in cerebral development and their deletion may be associated with mental retardation in CdCS patients. Deletion of the telomerase reverse transcriptase (hTERT) gene, localised to 5p15.33, could contribute to the phenotypic changes in CdCS. The critical regions were recently refined by using array comparative genomic hybridisation. The cat-like cry critical region was further narrowed using quantitative polymerase chain reaction (PCR) and three candidate genes were characterised in this region. The diagnosis is based on typical clinical manifestations. Karyotype analysis and, in doubtful cases, FISH analysis will confirm the diagnosis. There is no specific therapy for CdCS but early rehabilitative and educational interventions improve the prognosis and considerable progress has been made in

  15. Learning about Cri du Chat Syndrome

    MedlinePlus

    ... chat syndrome - also known as 5p- syndrome and cat cry syndrome - is a rare genetic condition that ... du chat syndrome usually include a high-pitched cat-like cry, mental retardation, delayed development, distinctive facial ...

  16. Expression, crystallization and preliminary X-ray crystallographic analyses of two N-terminal acetyltransferase-related proteins from Thermoplasma acidophilum

    SciTech Connect

    Han, Sang Hee; Ha, Jun Yong; Kim, Kyoung Hoon; Oh, Sung Jin; Kim, Do Jin; Kang, Ji Yong; Yoon, Hye Jin; Kim, Se-Hee; Seo, Ji Hae; Kim, Kyu-Won; Suh, Se Won

    2006-11-01

    An N-terminal acetyltransferase ARD1 subunit-related protein (Ta0058) and an N-terminal acetyltransferase-related protein (Ta1140) from T. acidophilum were crystallized. X-ray diffraction data were collected to 2.17 and 2.40 Å, respectively. N-terminal acetylation is one of the most common protein modifications in eukaryotes, occurring in approximately 80–90% of cytosolic mammalian proteins and about 50% of yeast proteins. ARD1 (arrest-defective protein 1), together with NAT1 (N-acetyltransferase protein 1) and possibly NAT5, is responsible for the NatA activity in Saccharomyces cerevisiae. In mammals, ARD1 is involved in cell proliferation, neuronal development and cancer. Interestingly, it has been reported that mouse ARD1 (mARD1{sup 225}) mediates ∊-acetylation of hypoxia-inducible factor 1α (HIF-1α) and thereby enhances HIF-1α ubiquitination and degradation. Here, the preliminary X-ray crystallographic analyses of two N-terminal acetyltransferase-related proteins encoded by the Ta0058 and Ta1140 genes of Thermoplasma acidophilum are reported. The Ta0058 protein is related to an N-terminal acetyltransferase complex ARD1 subunit, while Ta1140 is a putative N-terminal acetyltransferase-related protein. Ta0058 shows 26% amino-acid sequence identity to both mARD1{sup 225} and human ARD1{sup 235}.The sequence identity between Ta0058 and Ta1140 is 28%. Ta0058 and Ta1140 were overexpressed in Escherichia coli fused with an N-terminal purification tag. Ta0058 was crystallized at 297 K using a reservoir solution consisting of 0.1 M sodium acetate pH 4.6, 8%(w/v) polyethylene glycol 4000 and 35%(v/v) glycerol. X-ray diffraction data were collected to 2.17 Å. The Ta0058 crystals belong to space group P4{sub 1} (or P4{sub 3}), with unit-cell parameters a = b = 49.334, c = 70.384 Å, α = β = γ = 90°. The asymmetric unit contains a monomer, giving a calculated crystal volume per protein weight (V{sub M}) of 2.13 Å{sup 3} Da{sup −1} and a solvent content of 42

  17. Internet Chat in Simulations: Taking BULLYING Online

    ERIC Educational Resources Information Center

    Hull, Emily Blackshear

    2008-01-01

    This article discusses the pedagogical implications of using Internet chat in simulations for second-language learners. The author reviews several published simulations and explains how to use Internet chat effectively in the classroom. The author also relays her experience with using Internet chat with the BULLYING simulation.

  18. Constructing Sexuality and Identity in an Online Teen Chat Room

    ERIC Educational Resources Information Center

    Subrahmanyam, K.; Greenfield, P. M.; Tynes, B.

    2004-01-01

    In this article, we propose that adolescents' online interactions are both a literal and a metaphoric screen for representing major adolescent developmental issues, such as sexuality and identity. Because of the public nature of Internet chat rooms, they provide an open window into the expression of adolescent concerns. Our study utilizes this…

  19. TESTING AND ANALYSES OF CHAT AND ASPHALT-CONTAINING CHAT

    EPA Science Inventory

    Granular mine waste are generated from the extraction and beneficiation of lead/zinc minerals. The fine gravel waste, commonly known as chat, in the Tristate Mining District contains elevated levels of lead, zinc and cadmium which can result in potentially serious human health a...

  20. Immunoreactivity for Choline Acetyltransferase of Peripheral-Type (pChAT) in the Trigeminal Ganglion Neurons of the Non-Human Primate Macaca fascicularis

    PubMed Central

    Koga, Tsuneyuki; Bellier, Jean-Pierre; Kimura, Hiroshi; Tooyama, Ikuo

    2013-01-01

    Transcripts of the choline acetyltransferase (ChAT) gene reveal a number of different splice variants including ChAT of a peripheral type (pChAT). Immunohistochemical staining of the brain using an antibody against pChAT clearly revealed peripheral cholinergic neurons, but failed to detect cholinergic neurons in the central nervous system. In rodents, pChAT-immunoreactivity has been detected in cholinergic parasympathetic postganglionic and enteric ganglion neurons. In addition, pChAT has been observed in non-cholinergic neurons such as peripheral sensory neurons in the trigeminal and dorsal root ganglia. The common type of ChAT (cChAT) has been investigated in many parts of the brain and the spinal cord of non-human primates, but little information is available about the localization of pChAT in primate species. Here, we report the detection of pChAT immunoreactivity in trigeminal ganglion (TG) neurons and its co-localization with Substance P (SP) and/or calcitonin gene-related peptide (CGRP) in the cynomolgus monkey, Macaca fascicularis. Neurons positive for pChAT were observed in a rather uniform pattern in approximately half of the trigeminal neurons throughout the TG. Most pChAT-positive neurons had small or medium-sized cell bodies. Double-immunofluorescence staining showed that 85.1% of SP-positive cells and 74.0% of CGRP-positive cells exhibited pChAT immunoreactivity. Most pChAT-positive cells were part of a larger population of neurons that co-expressed SP and/or CGRP. PMID:23720604

  1. Chat Widgets for Science Libraries

    ERIC Educational Resources Information Center

    Meier, John J.

    2008-01-01

    This paper describes chat widgets, chunks of code that can be embedded on a web site to appear as an instant messaging system, and how they can be used on a science library web site to better serve library users. Interviews were conducted concerning experiences at science and humanities libraries and more similarities than differences were…

  2. Small CHAT plant. Final report

    SciTech Connect

    Nakhamkin, M.; Swenson, E.

    1997-11-01

    The Cascaded Humidified Advanced Turbine (CHAT) concept applied to small capacity simple cycle gas turbines fulfills the need for a small capacity, highly efficient, cost effective, flexible, and reliable plant with near term delivery. The objective of this report is to provide a status of the development of the small CHAT plant based including performance and cost estimates, potential suppliers, and operating advantages offered by the cycle itself. The small CHAT plant based upon the use of the Allison 501 KM7 engine on the low pressure power generation shaft produces 11.1 MW at ISO conditions with a net plant efficiency of 44.1%, LHV. This design requires only minor modification to the Allison KM engine. At maximum power, the plant can produce 12.8 MW at an efficiency of 43.1%. The estimated turn key capital cost of the plant at maximum power rating is approximately $750/kW. The next generation CHAT plant which requires additional modification to the Allison shaft is expected to produce 12.2 MW at 46.4% efficiency.

  3. The role of nitric oxide in the PKA inhibitor induced spatial memory deficits in rat: involvement of choline acetyltransferase.

    PubMed

    Najafi, Sheyda; Payandemehr, Borna; Tabrizian, Kaveh; Shariatpanahi, Marjan; Nassireslami, Ehsan; Azami, Kian; Mohammadi, Mojdeh; Asadi, Farideh; Roghani, Ali; Sharifzadeh, Mohammad

    2013-08-15

    Several lines of evidence show that cAMP-PKA signaling pathway plays critical role in memory functions and suggest nitric oxide as an important modulator in learning and memory. In this study, we assessed the effects of intra-hippocampal infusion of H-89, a selective PKAII inhibitor, and 1400 W, a selective inducible nitric oxide synthase (iNOS) inhibitor, on spatial memory in rats. By using the Morris water maze, spatial memory retention parameters were examined 48 h after the infusions through measuring escape latency, traveled distance, and swimming speed. The rats receiving intra-hippocampal infusions of 1400 W (100 µM/side) showed a significant reduction (*P<0.05) in escape latency and traveled distance in comparison with the control saline group. In contrast, a significant increase (**P<0.01) in escape latency and traveled distance was observed after infusion of 10 µM H-89. Moreover, among combination groups, co-administration of 1400 W (400 µM/side) with 10 µM/side of H-89 caused a significant reduction (*P<0.05) in escape latency and traveled distance in comparison with the H-89 group. Also, we evaluated the molecular effects of 1400 W on the expression of choline acetyltransferase (ChAT), a cholinergic marker, in the CA1 region of the hippocampus and medial septal area (MSA). Immunohistochemical analysis of post-training bilateral intra-hippocampal infusion of 1400 W revealed a significant increase in ChAT immunoreactivity levels in both the CA1 and the MSA regions. Overall, the results suggest that 1400 W has protective effect against H89-induced spatial memory impairment. Moreover, the observed memory improvements caused by 1400 W infusions, might be due to interaction of iNOS with the cholinergic system. PMID:23834774

  4. Coexistence of choline acetyltransferase and GABA in axon terminals in the dorsal cap of the rat inferior olive.

    PubMed

    Caffé, A R; Hawkins, R K; De Zeeuw, C I

    1996-06-10

    The dorsal cap of Kooy of the inferior olive (DC) is involved in compensatory eye movements. The rat DC receives a prominent input from the nucleus prepositus hypoglossi (NPH); part of these axon terminals are immunoreactive for choline acetyltransferase (ChAT) and part of them are GABAergic. In the present study we investigated the fine distribution of cholinergic terminals in the rat DC, and the possible coexistence of ChAT and GABA. ChAT-positive terminals were observed throughout the entire neuropil of the rat DC contacting both extraglomerular and intraglomerular dendrites. Twenty nine percent of these terminals also contained GABA. The ChAT/GABA double-labelled terminals showed the same morphological characteristics as terminals traced from the NPH. The present data demonstrate colocalization of ChAT and GABA in axon terminals of the rat DC and strongly suggest that neurons in the NPH are the source of these profiles. PMID:8816268

  5. Virtual reference: chat with us!

    PubMed

    Lapidus, Mariana; Bond, Irena

    2009-01-01

    Virtual chat services represent an exciting way to provide patrons of medical libraries with instant reference help in an academic environment. The purpose of this article is to examine the implementation, marketing process, use, and development of a virtual reference service initiated at the Massachusetts College of Pharmacy and Health Sciences and its three-campus libraries. In addition, this paper will discuss practical recommendations for the future improvement of the service. PMID:19384714

  6. Correlation of ghrelin concentration and ghrelin, ghrelin-O-acetyltransferase (GOAT) and growth hormone secretagogue receptor 1a mRNAs expression in the proventriculus and brain of the growing chicken.

    PubMed

    Kitazawa, Takio; Hiraga, Takeo; Teraoka, Hiroki; Yaosaka, Noriko; Kaiya, Hiroyuki

    2015-01-01

    To determine mechanisms for age-related decrease of GHS-R1a expression in the chicken proventriculus, changes in mRNA expression of ghrelin and ghrelin-O-acetyltransferase (GOAT) as well as ghrelin concentrations in the proventriculus and plasma were examined in growing chickens. Changes in expression levels of ghrelin, GOAT and GHS-R1a mRNAs were also examined in different brain regions (pituitary, hypothalamus, thalamus, cerebellum, cerebral cortex, olfactory bulb, midbrain and medulla oblongata). Ghrelin concentrations in the proventriculus and plasma increased with aging and reached plateaus at 30-50 days after hatching. High level of ghrelin mRNA decreased at 3 days after hatching, and it became stable at half of the initial level. Expression levels of GHS-R1a and GOAT decreased 3 or 5 days after hatching and became stable at low levels. Significant negative correlations were found between plasma ghrelin and mRNA levels of GOAT and GHS-R1a. Expression levels of ghrelin mRNA were different in the brain regions, but a significant change was not seen with aging. GHS-R1a expression was detected in all brain regions, and age-dependent changes were observed in the pituitary and cerebellum. Different from the proventriculus, the expression of GOAT in the brain increased or did not change with aging. These results suggest that decreased GHS-R1a and GOAT mRNA expression in the proventriculus is due to endogenous ghrelin-induced down-regulation. Expression levels of ghrelin, GOAT and GHS-R1a in the brain were independently regulated from that in the proventriculus, and age-related and region-dependent regulation pattern suggests a local effect of ghrelin system in chicken brain. PMID:25435492

  7. Polymorphic variation in CHAT gene modulates general cognitive ability: An association study with random student cohort.

    PubMed

    Liu, Xu; Shi, Yuanyu; Niu, Binbin; Shi, Zhangyan; Li, Junlin; Ma, Zhe; Wang, Jian; Gong, Pingyuan; Zheng, Anyun; Zhang, Fuchang; Gao, Xiaocai; Zhang, Kejin

    2016-03-23

    The choline O-acetyltransferase (CHAT) gene has been associated with various human disorders that involve cognitive impairment or deficiency. However, the influence of disease-associated variants of CHAT on normal individuals remains dubious. Here we demonstrated the impact of CHAT sequence variants (G-120A) on general human cognitive ability in a cohort of 750 Chinese undergraduate students. A multiple choice questionnaire was used to obtain basic demographic information, such as parents' occupations and education levels. We also administered and scored the Raven's Standard Progressive Matrices (RSPM). A one-way analysis of variance (ANOVA) and Kruskal-Wallis test (K-W) revealed a significant association between sequence polymorphisms of G-120A and individuals' Raven score (p=0.031 for ANOVA and p=0.026 for K-W tests). Moreover, further hierarchical analysis showed a similar trend in the association between G-120A variants and Raven scores only in the female subjects (p=0.008 for ANOVA and p=0.024 for K-W tests) but not in the male subjects. The results of a multiple linear regression confirmed that after we controlled gender, age, birthplace and other non-genetic factors, CHAT G-120A polymorphisms still significantly influenced individual Raven scores (B=-0.70, SE=0.28, t=-2.50, p=0.013). Our results demonstrated that sequence variants of CHAT were associated with human cognitive ability in not only patients with psychiatric disorders but also normal healthy individuals. However, some issues remained indeterminable, such as gender differences and the extent of the influence on individuals' general cognitive abilities; thus, the further research using an independent random sample was required. PMID:26854842

  8. Going Prime Time with Live Chat Reference.

    ERIC Educational Resources Information Center

    Hoag, Tara J.; Cichanowicz, Edana McCaffrey

    2001-01-01

    Describes the development of the Suffolk Cooperative Library System's live, online chat reference service, a pilot project for public libraries in Suffolk County (New York). Topics include chat software selection; a virtual reference collection; marketing; funding; staffing; evaluation; expanded hours of service; email; and extracting data from…

  9. Investigating L2 Performance in Text Chat

    ERIC Educational Resources Information Center

    Sauro, Shannon; Smith, Bryan

    2010-01-01

    This study examines the linguistic complexity and lexical diversity of both overt and covert L2 output produced during synchronous written computer-mediated communication, also referred to as chat. Video enhanced chatscripts produced by university learners of German (N = 23) engaged in dyadic task-based chat interaction were coded and analyzed for…

  10. Focus on Form in Live Chats

    ERIC Educational Resources Information Center

    Chen, Wen-Chun; Eslami, Zohreh

    2013-01-01

    This study investigated the effectiveness of incidental focus on form in promoting second language development in text-based live chats. Sixteen college-level Taiwanese English language learners were partnered with American college students to complete two communicative tasks via synchronous chats on Instant Messenger. Language-related episodes…

  11. Chat reference service in medical libraries: part 1--An introduction.

    PubMed

    Dee, Cheryl R

    2003-01-01

    Chat reference services offer the opportunity to provide immediate access to quality information to meet the medical information needs of students, faculty, staff, physicians, nurses, and allied health care professionals. Part 1 of this two-part article on chat reference service in medical libraries is an introduction to the management of chat reference services and to features available for chat reference. The management of chat reference services raises issues of planning, staffing, selecting, and marketing. Planning issues focus on the identification of the users, the users' medical information needs, and the users' information-seeking behavior. Staffing issues relate to the selection of chat hours, the location of the chat service, and participation in collaborative agreements. Selecting chat software weighs the sophistication of the chat features against the related cost. Marketing uses techniques similar to traditional reference services and often begins slowly as chat expertise develops. Part 2 of the article discusses trends in chat reference services in medical libraries. PMID:12723810

  12. Protein N-terminal acetyltransferases in cancer.

    PubMed

    Kalvik, T V; Arnesen, T

    2013-01-17

    The human N-terminal acetyltransferases (NATs) catalyze the transfer of acetyl moieties to the N-termini of 80-90% of all human proteins. Six NAT types are present in humans, NatA-NatF, each is composed of specific subunits and each acetylates a set of substrates defined by the N-terminal amino-acid sequence. NATs have been suggested to act as oncoproteins as well as tumor suppressors in human cancers, and NAT expression may be both elevated and decreased in cancer versus non-cancer tissues. Manipulation of NATs in cancer cells induced cell-cycle arrest, apoptosis or autophagy, implying that these enzymes target a variety of pathways. Of particular interest is hNaa10p (human ARD1), the catalytic subunit of the NatA complex, which was coupled to a number of signaling molecules including hypoxia inducible factor-1α, β-catenin/cyclin D1, TSC2/mammalian target of rapamycin, myosin light chain kinase , DNA methyltransferase1/E-cadherin and p21-activated kinase-interacting exchange factors (PIX)/Cdc42/Rac1. The variety of mechanistic links where hNaa10p acts as a NAT, a lysine acetyltransferase or displaying a non-catalytic role, provide insights to how hNaa10p may act as both a tumor suppressor and oncoprotein. PMID:22391571

  13. Modeling the Interaction between β-Amyloid Aggregates and Choline Acetyltransferase Activity and Its Relation with Cholinergic Dysfunction through Two-Enzyme/Two-Compartment Model

    PubMed Central

    Fgaier, Hedia; Mustafa, Ibrahim H. I.; Awad, Asmaa A. R.; Elkamel, Ali

    2015-01-01

    The effect of β-amyloid aggregates on activity of choline acetyltransferase (ChAT) which is responsible for synthesizing acetylcholine (ACh) in human brain is investigated through the two-enzyme/two-compartment (2E2C) model where the presynaptic neuron is considered as compartment 1 while both the synaptic cleft and the postsynaptic neuron are considered as compartment 2 through suggesting three different kinetic mechanisms for the inhibition effect. It is found that the incorporation of ChAT inhibition by β-amyloid aggregates into the 2E2C model is able to yield dynamic solutions for concentrations of generated β-amyloid, ACh, choline, acetate, and pH in addition to the rates of ACh synthesis and ACh hydrolysis in compartments 1 and 2. It is observed that ChAT activity needs a high concentration of β-amyloid aggregates production rate. It is found that ChAT activity is reduced significantly when neurons are exposed to high levels of β-amyloid aggregates leading to reduction in levels of ACh which is one of the most significant physiological symptoms of AD. Furthermore, the system of ACh neurocycle is dominated by the oscillatory behavior when ChAT enzyme is completely inhibited by β-amyloid. It is observed that the direct inactivation of ChAT by β-amyloid aggregates may be a probable mechanism contributing to the development of AD. PMID:26413144

  14. Extending Prior Posts in Dyadic Online Text Chat

    ERIC Educational Resources Information Center

    Tudini, Vincenza

    2015-01-01

    This study explores whether chat users are able to extend prior, apparently completed posts in the dyadic online text chat context. Dyadic text chat has a unique turn-taking system, and most chat softwares do not permit users to monitor one another's written messages-in-progress. This is likely to impact on their use of online extensions as an…

  15. Perfume formulation: words and chats.

    PubMed

    Ellena, Céline

    2008-06-01

    What does it mean to create fragrances with materials from chemistry and/or from nature? How are they used to display their characteristic differences, their own personality? Is it easier to create with synthetic raw materials or with essential oils? This review explains why a perfume formulation corresponds in fact to a conversation, an interplay between synthetic and natural perfumery materials. A synthetic raw material carries a single information, and usually is very linear. Its smell is uniform, clear, and faithful. Natural raw materials, on the contrary, provide a strong, complex and generous image. While a synthetic material can be seen as a single word, a natural one such as rose oil could be compared to chatting: cold, warm, sticky, heavy, transparent, pepper, green, metallic, smooth, watery, fruity... full of information. Yet, if a very small amount of the natural material is used, nothing happens, the fragrance will not change. However, if a large amount is used, the rose oil will swallow up everything else. The fragrance will smell of nothing else except rose! To formulate a perfume is not to create a culinary recipe, with only dosing the ingredients in well-balanced amounts. To formulate rather means to flexibly knit materials together with a lively stitch, meeting or repelling each other, building a pleasant form, which is neither fixed, nor solid, nor rigid. A fragrance has an overall structure, which ranges from a clear sound, made up of stable, unique, and linear items, to a background chat, comfortable and reassuring. But that does, of course, not mean that there is only one way of creating a fragrance! PMID:18618806

  16. Molecular Motor MYO1C, Acetyltransferase KAT6B and Osteogenetic Transcription Factor RUNX2 Expression in Human Masseter Muscle Contributes to Development of Malocclusion

    PubMed Central

    Desh, Heather; Gray, S Lauren; Horton, Michael J; Raoul, Gwenael; Rowlerson, Anthea M; Ferri, Joel; Vieira, Alexandre R; Sciote, James J

    2014-01-01

    Objective Type I myosins are molecular motors necessary for glucose transport in the cytoplasm and initiation of transcription in the nucleus. Two of these, MYO1H and MYO1C, are paralogs which may be important in the development of malocclusion. The objective of this study was to investigate their gene expression in the masseter muscle of malocclusion subjects. Two functionally related proteins known to contribute to malocclusion were also investigated: KAT6B (a chromatin remodeling epigenetic enzyme which is activated by MYO1C) and RUNX2 (a transcription factor regulating osteogenesis which is activated by KAT6B). Design Masseter muscle samples and malocclusion classifications were obtained from orthognathic surgery subjects. Muscle was sectioned and immunostained to determine fiber type properties. RNA was isolated from the remaining sample to determine expression levels for the four genes by TaqMan® RT-PCR. Fiber type properties, gene expression quantities and malocclusion classification were compared. Results There were very significant associations (P<0.0000001) between MYO1C and KAT6B expressions. There were also significant associations (P<0.005) between RUNX2 expression and masseter muscle type II fiber properties. Very few significant associations were identified between MYO1C and masseter muscle fiber type properties. Conclusions The relationship between MYO1C and KAT6B suggests that the two are interacting in chromatin remodeling for gene expression. This is the nuclear myosin1 (NM1) function of MYO1C. A surprising finding is the relationship between RUNX2 and type II masseter muscle fibers, since RUNX2 expression in mature muscle was previously unknown. Further investigations are necessary to elucidate the role of RUNX2 in adult masseter muscle. PMID:24698832

  17. The Cascaded Humidified Advanced Turbine (CHAT)

    SciTech Connect

    Nakhamkin, M.; Swensen, E.C.; Wilson, J.M.; Gaul, G.; Polsky, M.

    1996-07-01

    This paper introduces the Cascaded Humidified Advanced Turbine (CHAT) plant, a gas turbine based power generation plant utilizing intercooling, reheat, and humidification. It is based upon the integration of an existing heavy duty gas turbine with an additional shaft comprising industrial compressors and high pressure expander. CHAT capitalizes on the latest proven gas turbine technology, which, combined with a sophisticated thermal cycle configuration, results in substantial improvement in gas turbine efficiency, compared to a simple cycle, while still maintaining typical advantages and merits of a combustion turbine plant. Built with a commercial combustion turbine and available industrial compressors and expanders, the CHAT plant does not require extensive product development and testing. As a result, the CHAT power plant can be offered with specific capital costs up to 20 percent lower than the combined cycle plant, and with competing efficiency. Compared to a combined cycle plant, the CHAT plant offers lower emissions (due to air humidification) and other significant operating advantages with regard to start-up time and costs, better efficiency at part load, lower power degradation at higher ambient temperatures, and simpler operations and maintenance due to elimination of the complexities and costs associated with steam production. The CHAT plant also integrates very effectively with coal gasification and particularly well with the water quench design. This feature has been discussed in previous publications.

  18. The Chat Is Coming from inside the House: An Analysis of Perceived Chat Behavior and Reality

    ERIC Educational Resources Information Center

    Berndt-Morris, Elizabeth; Minnis, Samantha M.

    2014-01-01

    When looking for ways to improve library services, we considered what data sources were readily available to us and how we could harvest and use this data. We investigated three years of chat reference statistics at Central Michigan University, a large research institution, to gain a better understanding of our patrons' chat behavior. We then…

  19. Chat about what matters most: an analysis of chat contributions posted to an outpatient fertility website.

    PubMed

    Van Selm, Martine; Tuil, Wouter; Verhaak, Christianne; Woldringh, Gwendolyn; Kremer, Jan

    2008-12-01

    A content analysis of chat utterances generated by in vitro fertilization (IVF) patients and healthcare professionals revealed that most chat is about the treatment itself and not about childlessness; 56% discloses psychological aspects, 27% physical aspects, and 17% social aspects of the treatment; and that accounts of both external and internal coping behaviors could be identified. PMID:18954274

  20. Drug Facts Chat Day: NIH Experts Answer Students' Drug Questions

    MedlinePlus

    ... Home Current Issue Past Issues Drug Facts Chat Day: NIH Experts Answer Students' Drug Questions Past Issues / ... Drug Abuse during their first Drug Facts Chat Day. Photo courtesy of NIDA The questions poured in… ...

  1. Choline acetyltransferase immunoreactive cortical interneurons do not occur in all rodents: a study of the phylogenetic occurrence of this neural characteristic.

    PubMed

    Bhagwandin, Adhil; Fuxe, Kjell; Manger, Paul R

    2006-12-01

    The present study was designed to provide results aimed at testing whether the interneurons with choline acetyltransferase immunoreactivity (ChAT), probably representing GABA interneurons, found in the cerebral cortex of the rat represent a common feature of the order Rodentia. Initially we verified the presence of ChAT immunoreactive bipolar cell bodies, axons and terminal-like fibres in pigmented (Long-Evans) and non-pigmented (Sprague-Dawley) strains of Rattus norvegicus, confirming that the ChAT polyclonal antibodies (AB144P and AB143, Chemicon; VChAT, Sigma) with the immunohistochemical techniques used provided the same staining as previously described for this species. We then examined pigmented (AKR3) and non-pigmented (C3H) strains of Mus musculus, wild caught striped mice (Rhabdomys pumilio), bushveld gerbil (Tatera brantsii), greater canerat (Thryonomys swinderianus) and common molerat (Cryptomys hottentotus). The AB144P antibody revealed cortical interneurons in both strains of M. musculus and in R. pumilio, but not in the other species. In all species/strains cortical ChAT immunoreactive axons and terminal-like fibres were localized with the AB144P antibody. In the non-Rattus species/strains there was no evidence for localization of ChAT immunoreactivity in any cortical cell bodies using the AB143 and vesicular acetylcholine transporter (VChAT) antibodies despite extensive localization in axons and terminal-like fibres. It is concluded that bipolar cortical GABA interneurons in certain rodent species may develop ChAT immunoreactivity but not VChAT immunoreactivity making the cholinergic relevance of ChAT in the GABA interneurons uncertain and may exclude these neurons from being part of the traditionally defined cholinergic system. PMID:17049807

  2. Chat Rooms: Teens Hanging Out on the Web.

    ERIC Educational Resources Information Center

    Purdy, Rebecca; Web Surfers from Central Rappahannock Regional Library

    2002-01-01

    Discusses the use of chat rooms by teens in libraries, including educational reasons and socialization. Considers problems encountered when using chat, including viruses; stresses the need for establishing safety tips; and provides descriptions of five Web sites that allow chat, including instant messaging. (LRW)

  3. You Are There: No Budget for Travel? Try Video Chat

    ERIC Educational Resources Information Center

    Langhorst, Eric

    2009-01-01

    The author discusses how he used video chat as an alternative to a physical trip. Any teacher with an Internet hookup and a $30 webcam can connect with anyone in the world using video chat. Programs like Skype Video and the Google Mail's video chat function make it easy and, best of all, are completely free. The author discusses how to get started…

  4. The Use of Chat in EFL/ESL.

    ERIC Educational Resources Information Center

    d'Eca, Teresa Almeida

    2003-01-01

    Presents the case for using chat (synchronous online communication) in the language classroom from the point of view of a teacher with positive experiences and a balanced awareness of the potential of the medium. Discuses how to integrate chat in language learning, examines the advantages and disadvantages of chat to the language learner, and…

  5. Visualising Knowledge from Chat Debates in Argument Diagrams

    ERIC Educational Resources Information Center

    Salminen, T.; Marttunen, M.; Laurinen, L.

    2010-01-01

    This study investigates whether combining chat discussion and construction of an argument diagram stimulates students to formulate new ideas in practising argumentation. In this study, 16 secondary school students discussed vivisection and gender equality in pairs using both free and structured chat tools. In structured chat, the students selected…

  6. Semiotic Processes in Chat-Based Problem-Solving Situations

    ERIC Educational Resources Information Center

    Schreiber, Christof

    2013-01-01

    This article seeks to illustrate the analysis of episodes of chat sessions based on Charles Sanders Peirce's triadic sign relation. The episodes are from a project called "Math-Chat", which is based on the use of mathematical inscriptions in an experimental setting. What is characteristic of this chat setting is that pupils are required to…

  7. No evidence for role of extracellular choline-acetyltransferase in generation of gamma oscillations in rat hippocampal slices in vitro.

    PubMed

    Hollnagel, J O; ul Haq, R; Behrens, C J; Maslarova, A; Mody, I; Heinemann, U

    2015-01-22

    Acetylcholine (ACh) is well known to induce persistent γ-oscillations in the hippocampus when applied together with physostigmine, an inhibitor of the ACh degrading enzyme acetylcholinesterase (AChE). Here we report that physostigmine alone can also dose-dependently induce γ-oscillations in rat hippocampal slices. We hypothesized that this effect was due to the presence of choline in the extracellular space and that this choline is taken up into cholinergic fibers where it is converted to ACh by the enzyme choline-acetyltransferase (ChAT). Release of ACh from cholinergic fibers in turn may then induce γ-oscillations. We therefore tested the effects of the choline uptake inhibitor hemicholinium-3 (HC-3) on persistent γ-oscillations either induced by physostigmine alone or by co-application of ACh and physostigmine. We found that HC-3 itself did not induce γ-oscillations and also did not prevent physostigmine-induced γ-oscillation while washout of physostigmine and ACh-induced γ-oscillations was accelerated. It was recently reported that ChAT might also be present in the extracellular space (Vijayaraghavan et al., 2013). Here we show that the effect of physostigmine was prevented by the ChAT inhibitor (2-benzoylethyl)-trimethylammonium iodide (BETA) which could indicate extracellular synthesis of ACh. However, when we tested for effects of extracellularly applied acetyl-CoA, a substrate of ChAT for synthesis of ACh, physostigmine-induced γ-oscillations were attenuated. Together, these findings do not support the idea that ACh can be synthesized by an extracellularly located ChAT. PMID:25453770

  8. Evaluating the Quality of a Chat Service

    ERIC Educational Resources Information Center

    Arnold, Julie; Kaske, Neal K.

    2005-01-01

    A quantitative study of a university chat reference service (online synchronous) addresses the following research questions: (1) What types of questions are being asked? (2) Who is asking the questions of the service? and (3) Did the customers get correct answers to their questions? All the transcripts (351) from January through August 2002 were…

  9. First Things First: Internet Relay Chat Openings.

    ERIC Educational Resources Information Center

    Rintel, E. Sean; Mulholland, Joan; Pittam, Jeffery

    2001-01-01

    Argues that Internet Relay Chat (IRC) research needs to systematically address links between interaction structures, technological mediation and the instantiation and development of interpersonal relationships. Finds that openings that occur directly following user's entries into public IRC channels are often ambiguous, can disrupt relationship…

  10. Online "Chat" Facilities as Pedagogic Tools

    ERIC Educational Resources Information Center

    Kirkpatrick, Graeme

    2005-01-01

    This article assesses the pedagogic value of the "chat" facility in the Blackboard integrated learning platform. It draws on a case study carried out by the author in the 2001-2 academic session. A level three class in research methods involved students in group working away from class and student feedback indicated that more support was needed to…

  11. Sign Communication in Cri du Chat Syndrome

    ERIC Educational Resources Information Center

    Erlenkamp, Sonja; Kristoffersen, Kristian Emil

    2010-01-01

    This paper presents findings from a study on the use of sign supported Norwegian (SSN) in two individuals with Cri du chat syndrome (CCS). The study gives a first account of some selected aspects of production and intelligibility of SSN in CCS. Possible deviance in manual parameters, in particular inter- and/or intra-subject variation in the use…

  12. Recognizing connotative meaning in military chat communications

    NASA Astrophysics Data System (ADS)

    Budlong, Emily R.; Walter, Sharon M.; Yilmazel, Ozgur

    2009-05-01

    Over the last five to seven years the use of chat in military contexts has expanded quite significantly, in some cases becoming a primary means of communicating time-sensitive data to decision makers and operators. For example, during humanitarian operations with Joint Task Force-Katrina, chat was used extensively to plan, task, and coordinate predeployment and ongoing operations. The informal nature of chat communications allows the relay of far more information than the technical content of messages. Unlike formal documents such as newspapers, chat is often emotive. "Reading between the lines" to understand the connotative meaning of communication exchanges is now feasible, and often important. Understanding the connotative meaning of text is necessary to enable more useful automatic intelligence exploitation. The research project described in this paper was directed at recognizing user connotations of uncertainty and urgency. The project built a matrix of speech features indicative of these categories of meaning, developed data mining software to recognize them, and evaluated the results.

  13. Inhibition of Histone Acetyltransferase by Glycosaminoglycans

    PubMed Central

    Buczek-Thomas, Jo Ann; Hsia, Edward; Rich, Celeste B.; Foster, Judith A.; Nugent, Matthew A.

    2008-01-01

    Histone acetyltransferases (HATs) are a class of enzymes that participate in modulating chromatin structure and gene expression. Altered HAT activity has been implicated in a number of diseases, yet little is known about the regulation of HATs. In this study, we report that glycosaminoglycans are potent inhibitors of p300 and pCAF HAT activities in vitro, with heparin and heparan sulfate proteoglycans being the most potent inhibitors. The mechanism of inhibition by heparin was investigated. The ability of heparin to inhibit HAT activity was in part dependent upon its size and structure, as small heparin-derived oligosaccharides (> 8 sugars) and N-desulfated or O-desulfated heparin showed reduced inhibitory activity. Heparin was shown to bind to pCAF; and enzyme assays indicated that heparin shows the characteristics of a competitive-like inhibitor causing an ~50-fold increase in the apparent Km of pCAF for histone H4. Heparan sulfate proteoglycans isolated from corneal and pulmonary fibroblasts inhibited HAT activity with similar effectiveness as heparin. As evidence that endogenous glycosaminoglycans might be involved in modulating histone acetylation, the direct addition of heparin to pulmonary fibroblasts resulted in an ~50% reduction of histone H3 acetylation after 6 hours of treatment. In addition, Chinese hamster ovary cells deficient in glycosaminoglycan synthesis showed increased levels of acetylated histone H3 compared to wild-type parent cells. Glycosaminoglycans represent a new class of HAT inhibitors that might participate in modulating cell function by regulating histone acetylation. PMID:18459114

  14. Chatting behavior and patient satisfaction in the outpatient encounter.

    PubMed Central

    Daaleman, Timothy P.; Mueller, Jan

    2004-01-01

    Communication studies suggest that patient sociodemographic factors are embedded within medical encounters and impact patient expectations, judgments, and outcomes, such as satisfaction. Physician chatting has been suggested as one way to enhance patient satisfaction; however, little is known about chatting within the context of the clinical encounter or of the interaction of chatting with patient sociodemographic factors and patient satisfaction. The study's purpose was to determine the prevalence and patterns of chatting, and to examine the association of chatting with patient sociodemographic factors and patient satisfaction with their physician. A convenience sample of adult outpatients from an urban family practice underwent an exit interview. A total of 105 patients participated; 63 (61%) reported chatting from their recent encounter. No sociodemographic differences were observed between patients reporting chatting and those reporting no chatting. Chatting behavior pertaining to the patient's family or friends was the predominant topic, and more nonwhite (30%) than white (13%) patients reported this activity (p<0.001). There was no significant difference in satisfaction scores between patients that reported chatting behavior and those that did not (23.73 vs. 22.79, p=0.076). In addition, there was no difference in patient satisfaction scores for physician personal manner, technical skill, visit explanation, time spent with the physician, and overall visit between the chatting and nonchatting groups. PMID:15160982

  15. Acetyl-L-carnitine restores choline acetyltransferase activity in the hippocampus of rats with partial unilateral fimbria-fornix transection.

    PubMed

    Piovesan, P; Quatrini, G; Pacifici, L; Taglialatela, G; Angelucci, L

    1995-02-01

    Transection of the fimbria-fornix bundle in adult rats results in degeneration of the septohippocampal cholinergic pathway, reminiscent of that occurring in aging as well as Alzheimer disease. We report here a study of the effect of a treatment with acetyl-L-carnitine (ALCAR) in three-month-old Fischer 344 rats bearing a partial unilateral fimbria-fornix transection. ALCAR is known to ameliorate some morphological and functional disturbances in the aged central nervous system (CNS). We used choline acetyltransferase (ChAT) and acetyl cholinesterase (AChE) as markers of central cholinergic function, and nerve growth factor (NGF) levels as indicative of the trophic regulation of the medio-septal cholinergic system. ChAT and AChE activities were significantly reduced in the hippocampus (HIPP) ipsilateral to the lesion as compared to the contralateral one, while no changes were observed in the septum (SPT), nucleus basalis magnocellularis (NBM) or frontal cortex (FCX). ALCAR treatment restored ChAT activity in the ipsilateral HIPP, while AChE levels were not different from those of untreated animals, and did not affect NGF content in either SPT or HIPP. PMID:7793306

  16. Genetic Association of CHAT rs3810950 and rs2177369 Polymorphisms with the Risk of Alzheimer's Disease: A Meta-Analysis

    PubMed Central

    Liu, Yong; Chen, Qicong; Liu, Xu; Dou, Mengmeng; Li, Silu; Zhou, Jiahui; Liu, Hong

    2016-01-01

    Choline acetyltransferase (CHAT) rs3810950 and rs2177369 polymorphisms have been implicated in susceptibility to Alzheimer's disease (AD). Due to the inconsistent results from previous studies, a meta-analysis was performed to estimate the association between these polymorphisms and AD risk more precisely. Pooled results of our meta-analysis indicated CHAT rs2177369 polymorphism was correlated with decreasing AD risk in one of five genetic models (dominant: OR = 0.77, 95% CI: 0.62–0.96), while rs3810950 mutant was associated with AD development in three models (allelic: OR = 1.18, 95% CI: 1.01–1.37, homozygous: OR = 1.63, 95% CI: 1.09–2.42, and recessive: OR = 1.65, 95% CI: 1.20–2.26). In subgroup analysis by ethnicity, the association between CHAT rs3810950 polymorphism and AD risk was just found in the recessive model (OR = 1.47, 95% CI: 1.05–2.07) among Caucasians, while four genetic models (allelic: OR = 1.23, 95% CI: 1.01–1.48; homozygous: OR = 2.24, 95% CI: 1.48–3.39; dominant: OR = 1.21, 95% CI: 1.06–1.40; and recessive: OR = 2.18, 95% CI: 1.45–3.29) assumed this association in Asians. In conclusion, our meta-analysis indicated CHAT rs2177369 polymorphism might play a protective role in AD, while rs3810950 variant was a risk factor for AD but its single heterozygous mutations might not influence susceptibility to AD. PMID:27597977

  17. Genetic Association of CHAT rs3810950 and rs2177369 Polymorphisms with the Risk of Alzheimer's Disease: A Meta-Analysis.

    PubMed

    Liu, Yong; Chen, Qicong; Liu, Xu; Dou, Mengmeng; Li, Silu; Zhou, Jiahui; Liu, Hong; Wu, Yongfu; Huang, Zunnan

    2016-01-01

    Choline acetyltransferase (CHAT) rs3810950 and rs2177369 polymorphisms have been implicated in susceptibility to Alzheimer's disease (AD). Due to the inconsistent results from previous studies, a meta-analysis was performed to estimate the association between these polymorphisms and AD risk more precisely. Pooled results of our meta-analysis indicated CHAT rs2177369 polymorphism was correlated with decreasing AD risk in one of five genetic models (dominant: OR = 0.77, 95% CI: 0.62-0.96), while rs3810950 mutant was associated with AD development in three models (allelic: OR = 1.18, 95% CI: 1.01-1.37, homozygous: OR = 1.63, 95% CI: 1.09-2.42, and recessive: OR = 1.65, 95% CI: 1.20-2.26). In subgroup analysis by ethnicity, the association between CHAT rs3810950 polymorphism and AD risk was just found in the recessive model (OR = 1.47, 95% CI: 1.05-2.07) among Caucasians, while four genetic models (allelic: OR = 1.23, 95% CI: 1.01-1.48; homozygous: OR = 2.24, 95% CI: 1.48-3.39; dominant: OR = 1.21, 95% CI: 1.06-1.40; and recessive: OR = 2.18, 95% CI: 1.45-3.29) assumed this association in Asians. In conclusion, our meta-analysis indicated CHAT rs2177369 polymorphism might play a protective role in AD, while rs3810950 variant was a risk factor for AD but its single heterozygous mutations might not influence susceptibility to AD. PMID:27597977

  18. Neisseria meningitidis serogroup A capsular polysaccharide acetyltransferase, methods and compositions

    SciTech Connect

    Stephens, David S.; Gudlavalleti, Seshu K.; Tzeng, Yih-Ling; Datta, Anup K.; Carlson, Russell W.

    2011-02-08

    Provided are methods for recombinant production of an O-acetyltransferase and methods for acetylating capsular polysaccharides, especially those of a Serogroup A Neisseria meningitidis using the recombinant O-acetyltransferase, and immunogenic compositions comprising the acetylated capsular polysaccharide.

  19. Insights into the Specificity of Lysine Acetyltransferases*

    PubMed Central

    Tucker, Alex C.; Taylor, Keenan C.; Rank, Katherine C.; Rayment, Ivan; Escalante-Semerena, Jorge C.

    2014-01-01

    Reversible lysine acetylation by protein acetyltransferases is a conserved regulatory mechanism that controls diverse cellular pathways. Gcn5-related N-acetyltransferases (GNATs), named after their founding member, are found in all domains of life. GNATs are known for their role as histone acetyltransferases, but non-histone bacterial protein acetytransferases have been identified. Only structures of GNAT complexes with short histone peptide substrates are available in databases. Given the biological importance of this modification and the abundance of lysine in polypeptides, how specificity is attained for larger protein substrates is central to understanding acetyl-lysine-regulated networks. Here we report the structure of a GNAT in complex with a globular protein substrate solved to 1.9 Å. GNAT binds the protein substrate with extensive surface interactions distinct from those reported for GNAT-peptide complexes. Our data reveal determinants needed for the recognition of a protein substrate and provide insight into the specificity of GNATs. PMID:25381442

  20. Unintended Consequences: High phosphinothricin acetyltransferase activity causes reduced fitness in barley

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Selectable markers used in plant transformation, such as phosphinothricin acetyltransferase (PAT) derived from the bar gene, have been chosen for selection efficacy as well as for the absence of pleiotropic effects. Recent research has suggested that expression of bar in Arabidopsis affects the tran...

  1. Defining the Orphan Functions of Lysine Acetyltransferases

    PubMed Central

    2016-01-01

    Long known for their role in histone acetylation, recent studies have demonstrated that lysine acetyltransferases also carry out distinct “orphan” functions. These activities impact a wide range of biological phenomena including metabolism, RNA modification, nuclear morphology, and mitochondrial function. Here, we review the discovery and characterization of orphan lysine acetyltransferase functions. In addition to highlighting the evidence and biological role for these functions in human disease, we discuss the part emerging chemical tools may play in investigating this versatile enzyme superfamily. PMID:25591746

  2. Rapid quantitative assay for chloramphenicol acetyltransferase

    SciTech Connect

    Neumann, J.R.; Morency, C.A.; Russian, K.O.

    1987-05-01

    Measuring the expression of exogenous genetic material in mammalian cells is commonly done by fusing the DNA of interest to a gene encoding an easily-detected enzyme. Chloramphenicol acetyltransferase(CAT) is a convenient marker because it is not normally found in eukaryotes. CAT activity has usually been detected using a thin-layer chromatographic separation followed by autoradiography. An organic solvent extraction-based method for CAT detection has also been described, as well as a procedure utilizing HPLC analysis. Building on the extraction technique, they developed a rapid sensitive kinetic method for measuring CAT activity in cell homogenates. The method exploits the differential organic solubility of the substrate ((/sup 3/H) or (/sup 14/C)acetyl CoA) and the product (labeled acetylchloramphenicol). The assay is a simple one-vial, two-phase procedure and requires no tedious manipulations after the initial setup. Briefly, a 0.25 ml reaction with 100mM Tris-HCL, 1mM chloramphenicol, 0.1mM (/sup 14/C)acetyl CoA and variable amounts of cell homogenate is pipetted into a miniscintillation vial, overlaid with 5 ml of a water-immiscible fluor, and incubated at 37/sup 0/C. At suitable intervals the vial is counted and the CAT level is quantitatively determined as the rate of increase in counts/min of the labeled product as it diffuses into the fluor phase, compared to a standard curve. When used to measure CAT in transfected Balb 3T3 cells the method correlated well with the other techniques.

  3. The Effect of Choline Acetyltransferase Genotype on Donepezil Treatment Response in Patients with Alzheimer’s Disease

    PubMed Central

    Lee, Kang Uk; Lee, Jung Hie; Lee, Dong Young; Youn, Jong Chul; Kim, Jeong Lan; Moon, Seok Woo; Kim, Bong-Jo; Ryu, Seung-Ho; Kim, Moon Doo; Lee, Chang-Uk; Lee, Nam-Jin; Chang, Sung Man; Kim, Young Hoon; Kim, Do Hoon; Lee, Hae-Kook; Woo, Jong Inn; Kim, Ki Woong; Jhoo, Jin Hyeong

    2015-01-01

    Objective We examined the difference in responses to donepezil between carriers and non-carriers of the A allele at the +4 position of the choline acetyltransferase (ChAT) gene in Koreans. Methods Patients who met the criteria for probable Alzheimer’s disease (AD) (n=199) were recruited. Among these, 145 completed the 12-week follow-up evaluation and 135 completed the 26-week scheduled course. Differences and changes in the Korean version of the mini-mental state examination (MMSE-KC) score, Korean version of the Consortium to Establish a Registry for Alzheimer’s Disease Neuropsychological Assessment Battery (CERAD-K[N]) wordlist subtest score (WSS), CERAD-K(N) total score (TS), and the Korean version of geriatric depression scale (GDS-K) score between baseline and 12 weeks or 26 weeks were assessed by the Student’s t-test. Results At 12 weeks, the changes in the MMSE-KC score, CERAD-K(N) WSS, and CERAD-K(N) TS from baseline were not significant between ChAT A allele carriers and non-carriers; however, at 26 weeks, these changes were significantly larger in ChAT A allele carriers than in non-carriers (p=0.02 for MMSE-KC and p=0.03 for CERAD-K(N) WSS respectively). Conclusion Our findings in this study suggested that presence of the A allele at the +4 position of ChAT might positively influence the treatment effect of donepezil in the early stages of AD in Koreans. PMID:26243844

  4. TESTING AND ANALYSES OF CHAT AND ASPHALT-CONTAINING CHAT (PRESENTATION)

    EPA Science Inventory

    Granular mine waste are generated from the extraction and beneficiation of lead/zinc minerals. The fine gravel waste, commonly known as chat, in the Tristate Mining District contains elevated levels of lead, zinc and cadmium which can result in potentially serious human health a...

  5. Counseling Children at a Helpline: Chatting or Calling?

    ERIC Educational Resources Information Center

    Fukkink, Ruben; Hermanns, Jo

    2009-01-01

    In a quantitative content analysis, the telephone-based and Web-based support of the Dutch child helpline were studied. Both adult judges and the children themselves indicated that the quality of chat conversations was better than that of telephone conversations. Both the chat and telephone service succeeded in improving children's well-being and…

  6. Chatting It Up Online: Students Talk to a Favorite Author.

    ERIC Educational Resources Information Center

    Livingston, Pamela

    1999-01-01

    Explains procedures for students participating in an author chat using the Internet, based on experiences with children's author Mary Pope Osborne and a third grade class. Discusses equipment needs, how to formulate appropriate questions, and benefits of online chats, including the immediate response time. (LRW)

  7. The Value of Chat Reference Services: A Pilot Study

    ERIC Educational Resources Information Center

    Jacoby, JoAnn; Ward, David; Avery, Susan; Marcyk, Emilia

    2016-01-01

    This article explores student, instructor, and librarian perceptions of chat reference in the context of an introductory composition course. Participants in a mixed-method study responded to an anonymized chat transcript. While student respondents valued speed and efficiency, they were willing to receive instruction and open to questions that…

  8. Children's Experiences with Chat Support and Telephone Support

    ERIC Educational Resources Information Center

    Fukkink, Ruben G.; Hermanns, Jo M. A.

    2009-01-01

    Background: In line with the wider trend of offering support via the Internet, many counseling and referral services for children have introduced online chat, often in addition to a traditional telephone service. Methods: A comparative study was conducted between the telephone service and the confidential one-on-one online chat service of the…

  9. Generation of Human Embryonic Stem Cell Line Expressing zsGreen in Cholinergic Neurons Using CRISPR/Cas9 System.

    PubMed

    Zhou, Jing; Wang, Chencheng; Zhang, Kunshan; Wang, Yingying; Gong, Xi; Wang, Yanlu; Li, Siguang; Luo, Yuping

    2016-08-01

    Lineage specific human embryonic stem cell (hESC) reporter cell line is a versatile tool for biological studies on real time monitoring of differentiation, physiological and biochemical features of special cell types and pathological mechanism of disease. Here we report the generation of ChAT-zsGreen reporter hESC line that express zsGreen under the control of the choline acetyltransferase (ChAT) promoter using CRISPR (Clustered Regularly Interspersed Short Palindromic Repeats)/Cas9 system. We show that the ChAT-zsGreen hESC reporter cell lines retain the features of undifferentiated hESC. After cholinergic neuronal differentiation, cholinergic neurons were clearly labeled with green fluorescence protein (zsGreen). The ChAT-zsGreen reporter hESC lines are invaluable not only for the monitoring cholinergic neuronal differentiation but also for study physiological and biochemical hallmarks of cholinergic neurons. PMID:27113041

  10. Perceived safety and teen risk taking in online chat sites.

    PubMed

    McCarty, Cheryl; Prawitz, Aimee D; Derscheid, Linda E; Montgomery, Bette

    2011-03-01

    Framed by theories of adolescent development, this study explored relationships among adolescents' perceptions of chat-site safety, time spent chatting, and risky online behaviors. Tenth graders (N = 139) in rural Midwestern U.S. schools completed surveys. Factor analysis produced three factors each for perception of safety and risk-taking behaviors. Regression analyses revealed that perception of safety factors were useful in predicting online risk-taking behaviors. Teens with more social discomfort and those who thought it was safe to reveal personal information and trust chat-site "friends" were more likely to take risks. As time spent in chat sites increased, so did risk-taking behaviors. Implications for educators and parents are discussed, such as initiation of conversations about safe Internet use, parental participation in chat sites as teens' invited "friends," and school programs to teach safe online practices. PMID:20677982

  11. L-cysteine biosynthesis in Escherichia coli: nucleotide sequence and expression of the serine acetyltransferase (cysE) gene from the wild-type and a cysteine-excreting mutant.

    PubMed

    Denk, D; Böck, A

    1987-03-01

    Serine acetyltransferase (SAT) from Escherichia coli is subject to feedback inhibition by L-cysteine. A mutant was isolated which excretes L-cysteine because of a lesion in cysE, the structural gene for SAT, rendering the enzyme less feedback sensitive. To analyse the structural basis for this mutation the cysE genes both from wild-type E. coli and the mutant strain were cloned and their nucleotide sequences determined. The cysE gene contained an open reading frame consisting of 819 bp, equivalent to a protein of 273 amino acids. The mutant gene showed a single base change in position 767 resulting in a methionine to isoleucine substitution. A causal connection between this SAT sequence alteration, feedback insensitivity and L-cysteine excretion was demonstrated. The SAT from the wild-type strain was purified. It was composed of a single polypeptide chain migrating in SDS gels according to an Mr of 34,000. As in Salmonella typhimurium, the enzyme was associated in a bifunctional complex with O-acetylserine (thiol)-lyase. PMID:3309158

  12. Kinesin-II Is Required for Axonal Transport of Choline Acetyltransferase in Drosophila

    PubMed Central

    Ray, Krishanu; Perez, Sharon E.; Yang, Zhaohuai; Xu, Jenny; Ritchings, Bruce W.; Steller, Hermann; Goldstein, Lawrence S.B.

    1999-01-01

    KLP64D and KLP68D are members of the kinesin-II family of proteins in Drosophila. Immunostaining for KLP68D and ribonucleic acid in situ hybridization for KLP64D demonstrated their preferential expression in cholinergic neurons. KLP68D was also found to accumulate in cholinergic neurons in axonal obstructions caused by the loss of kinesin light chain. Mutations in the KLP64D gene cause uncoordinated sluggish movement and death, and reduce transport of choline acetyltransferase from cell bodies to the synapse. The inviability of KLP64D mutations can be rescued by expression of mammalian KIF3A. Together, these data suggest that kinesin-II is required for the axonal transport of a soluble enzyme, choline acetyltransferase, in a specific subset of neurons in Drosophila. Furthermore, the data lead to the conclusion that the cargo transport requirements of different classes of neurons may lead to upregulation of specific pathways of axonal transport. PMID:10545496

  13. Immunohistochemical localization of two types of choline acetyltransferase in neurons and sensory cells of the octopus arm.

    PubMed

    Sakaue, Yuko; Bellier, Jean-Pierre; Kimura, Shin; D'Este, Loredana; Takeuchi, Yoshihiro; Kimura, Hiroshi

    2014-01-01

    Cholinergic structures in the arm of the cephalopod Octopus vulgaris were studied by immunohistochemistry using specific antisera for two types (common and peripheral) of acetylcholine synthetic enzyme choline acetyltransferase (ChAT): antiserum raised against the rat common type ChAT (cChAT), which is cross-reactive with molluscan cChAT, and antiserum raised against the rat peripheral type ChAT (pChAT), which has been used to delineate peripheral cholinergic structures in vertebrates, but not previously in invertebrates. Western blot analysis of octopus extracts revealed a single pChAT-positive band, suggesting that pChAT antiserum is cross-reactive with an octopus counterpart of rat pChAT. In immunohistochemistry, only neuronal structures of the octopus arm were stained by cChAT and pChAT antisera, although the pattern of distribution clearly differed between the two antisera. cChAT-positive varicose nerve fibers were observed in both the cerebrobrachial tract and neuropil of the axial nerve cord, while pChAT-positive varicose fibers were detected only in the neuropil of the axial nerve cord. After epitope retrieval, pChAT-positive neuronal cells and their processes became visible in all ganglia of the arm, including the axial and intramuscular nerve cords, and in ganglia of suckers. Moreover, pChAT-positive structures also became detectable in nerve fibers connecting the different ganglia, in smooth nerve fibers among muscle layers and dermal connective tissues, and in sensory cells of the suckers. These results suggest that the octopus arm has two types of cholinergic nerves: cChAT-positive nerves from brain ganglia and pChAT-positive nerves that are intrinsic to the arm. PMID:23354679

  14. The histone acetyltransferase MOF overexpression blunts cardiac hypertrophy by targeting ROS in mice.

    PubMed

    Qiao, Weiwei; Zhang, Weili; Gai, Yusheng; Zhao, Lan; Fan, Juexin

    2014-06-13

    Imbalance between histone acetylation/deacetylation critically participates in the expression of hypertrophic fetal genes and development of cardiac hypertrophy. While histone deacetylases play dual roles in hypertrophy, current evidence reveals that histone acetyltransferase such as p300 and PCAF act as pro-hypertrophic factors. However, it remains elusive whether some histone acetyltransferases can prevent the development of hypertrophy. Males absent on the first (MOF) is a histone acetyltransferase belonging to the MYST (MOZ, Ybf2/Sas3, Sas2 and TIP60) family. Here in this study, we reported that MOF expression was down-regulated in failing human hearts and hypertrophic murine hearts at protein and mRNA levels. To evaluate the roles of MOF in cardiac hypertrophy, we generated cardiac-specific MOF transgenic mice. MOF transgenic mice did not show any differences from their wide-type littermates at baseline. However, cardiac-specific MOF overexpression protected mice from transverse aortic constriction (TAC)-induced cardiac hypertrophy, with reduced radios of heart weight (HW)/body weight (BW), lung weight/BW and HW/tibia length, decreased left ventricular wall thickness and increased fractional shortening. We also observed lower expression of hypertrophic fetal genes in TAC-challenged MOF transgenic mice compared with that of wide-type mice. Mechanically, MOF overexpression increased the expression of Catalase and MnSOD, which blocked TAC-induced ROS and ROS downstream c-Raf-MEK-ERK pathway that promotes hypertrophy. Taken together, our findings identify a novel anti-hypertrophic role of MOF, and MOF is the first reported anti-hypertrophic histone acetyltransferase. PMID:24802406

  15. M4M chat rooms: individual socialization and sexual autonomy.

    PubMed

    Sanders, T C

    2008-04-01

    This paper uses data from twenty-one online and in-person qualitative interviews to examine the meaning and use of chat rooms located on men for men (M4M) websites from the perspectives of men seeking men on the Internet. This research is inspired by recent public health and social sciences literature on gay websites and chat rooms. The data indicate that these online sites help expedite learning about sex and sexuality and, for men who are shy or geographically isolated, to interact with metropolitan gay communities. There is, however, a measure of stigma associated with use of these chat rooms, particularly by men who are older or in coupled relationships. Using these data, the paper argues that M4M chat rooms play a vital role in fostering the sexual autonomy of many men who frequent these venues and that sociologists should devote more study to the complexity of online social interaction. PMID:18432425

  16. Speaking Math: Using Chat in the Multicultural Math Classroom

    ERIC Educational Resources Information Center

    Graham, Janet; Hodgson, Ted

    2008-01-01

    Electronic communication is a powerful tool teachers can leverage to improve learning. In this article, the authors explain how they used chat and discussion forums to improve their mathematics classes, and how others can adapt their strategies across the curriculum.

  17. Structure of Mesorhizobium loti arylamine N-acetyltransferase 1

    SciTech Connect

    Holton, Simon J.; Dairou, Julien; Sandy, James; Rodrigues-Lima, Fernando; Dupret, Jean-Marie; Noble, Martin E. M.; Sim, Edith

    2005-01-01

    The crystal structure of a M. loti arylamine N-acetyltransferase 1 has been determined at 2.0 Å resolution. The arylamine N-acetyltransferase (NAT) enzymes have been found in a broad range of both eukaryotic and prokaryotic organisms. The NAT enzymes catalyse the transfer of an acetyl group from acetyl Co-enzyme A onto the terminal nitrogen of a range of arylamine, hydrazine and arylhydrazine compounds. Recently, several NAT structures have been reported from different prokaryotic sources including Salmonella typhimurium, Mycobacterium smegmatis and Pseudomonas aeruginosa. Bioinformatics analysis of the Mesorhizobium loti genome revealed two NAT paralogues, the first example of multiple NAT isoenzymes in a eubacterial organism. The M. loti NAT 1 enzyme was recombinantly expressed and purified for X-ray crystallographic studies. The purified enzyme was crystallized in 0.5 M Ca(OAc){sub 2}, 16% PEG 3350, 0.1 M Tris–HCl pH 8.5 using the sitting-drop vapour-diffusion method. A data set diffracting to 2.0 Å was collected from a single crystal at 100 K. The crystal belongs to the orthorhombic spacegroup P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 53.2, b = 97.3, c = 114.3 Å. The structure was refined to a final free-R factor of 24.8%. The structure reveals that despite low sequence homology, M. loti NAT1 shares the common fold as reported in previous NAT structures and exhibits the same catalytic triad of residues (Cys-His-Asp) in the active site.

  18. Regulation and function of histone acetyltransferase MOF.

    PubMed

    Yang, Yang; Han, Xiaofei; Guan, Jingyun; Li, Xiangzhi

    2014-03-01

    The mammalian MOF (male absent on the first), a member of the MYST (MOZ, YBF2, SAS2, and Tip60) family of histone acetyltransferases (HATs), is the major enzyme that catalyzes the acetylation of histone H4 on lysine 16. Acetylation of K16 is a prevalent mark associated with chromatin decondensation. MOF has recently been shown to play an essential role in maintaining normal cell functions. In this study, we discuss the important roles of MOF in DNA damage repair, apoptosis, and tumorigenesis. We also analyze the role of MOF as a key regulator of the core transcriptional network of embryonic stem cells. PMID:24452550

  19. Who benefits from chatting, and why? The roles of extraversion and supportiveness in online chatting and emotional adjustment.

    PubMed

    Van Zalk, Maarten H W; Branje, Susan J T; Denissen, Jaap; Van Aken, Marcel A G; Meeus, Wim H J

    2011-09-01

    The current study aimed to provide more insight into the role of online chatting in young adults' emotional adjustment. A model was tested that takes into account (a) extraversion of individuals who communicate online, (b) the kind of peers these individuals communicate with online (i.e., online-exclusive peers vs. friends), and (c) the extent to which effects of online chatting on emotional adjustment are mediated by individuals' ability to provide support to others. Young adults (age M = 18.9) filled out questionnaires about themselves and their fellow students at three measurements with a 4-month interval. Results showed that only for less extraverted individuals, chatting with peers found exclusively online directly predicted higher self-esteem and indirectly predicted less depressive symptoms through increases in supportiveness. Thus, results supported a model of social compensation where effects of online chatting with online-exclusive peers improved young adults' emotional adjustment. PMID:21673194

  20. In vitro inhibition of choline acetyltransferase by a series of 2-benzylidene-3-quinuclidinones

    SciTech Connect

    Capacio, B.R.

    1988-01-01

    Ten substituted 2-benzylidene-3-quinuclidinones were synthesized and evaluated for their relative potency as in vitro inhibitors of choline acetyltransferase (ChAT). Acetylcholine (ACh) synthesis was followed radiometrically by the incorporation of labeled acetate originating from {sup 14}C-acetyl-CoA. Woolf-Augustinsson-Hofstee data analysis was used to calculate Vmax, Km, and Ki values. The inhibition was found to be noncompetitive or uncompetitive with respect to choline. Quantitative structure activity relationship correlations demonstrated a primary dependence on {kappa}-{sigma}, as well as steric properties of the substituted benzene ring. Additional radiometric and spectrophotometric were performed with 2-(3{prime}-methyl)-benzylidene-3-quinuclidinone, one of the more potent analogs, to further elucidate the inhibitory mechanism. ChAT-mediated cleavage of ACh was measured spectrophotometrically by following the appearance of NADH at 340 nanometers in an enzyme coupled assay. Lineweaver-Burk analysis indicated mixed or uncompetitive inhibition with respect to both substrates of the forward reaction, suggesting interference with a rate limiting step.

  1. The histone acetyltransferase hMOF suppresses hepatocellular carcinoma growth.

    PubMed

    Zhang, Jin; Liu, Hui; Pan, Hao; Yang, Yuan; Huang, Gang; Yang, Yun; Zhou, Wei-Ping; Pan, Ze-Ya

    2014-09-26

    Males absent on the first (MOF) is a histone acetyltransferase belongs to the MYST (MOZ, Ybf2/Sas3, Sas2 and TIP60) family. In mammals, MOF plays critical roles in transcription activation by acetylating histone H4K16, a prevalent mark associated with chromatin decondensation. MOF can also acetylate transcription factor p53 on K120, which is important for activation of pro-apoptotic genes; and TIP5, the largest subunit of NoRC, on K633. However, the role of hMOF in hepatocellular carcinoma remains unknown. Here we find that the expression of hMOF is significantly down-regulated in human hepatocellular carcinoma and cell lines. Furthermore, our survival analysis indicates that low hMOF expression predicts poor overall and disease-free survival. We demonstrate that hMOF knockdown promotes hepatocellular carcinoma growth in vitro and in vivo, while hMOF overexpression reduces hepatocellular carcinoma growth in vitro and in vivo. Mechanically, we show that hMOF regulates the expression of SIRT6 and its downstream genes. In summary, our findings demonstrate that hMOF participates in human hepatocellular carcinoma by targeting SIRT6, and hMOF activators may serve as potential drug candidates for hepatocellular carcinoma therapy. PMID:25181338

  2. Anacardic acid (6-nonadecyl salicylic acid), an inhibitor of histone acetyltransferase, suppresses expression of nuclear factor-κB–regulated gene products involved in cell survival, proliferation, invasion, and inflammation through inhibition of the inhibitory subunit of nuclear factor-κBα kinase, leading to potentiation of apoptosis

    PubMed Central

    Sung, Bokyung; Pandey, Manoj K.; Ahn, Kwang Seok; Yi, Tingfang; Chaturvedi, Madan M.; Liu, Mingyao

    2008-01-01

    Anacardic acid (6-pentadecylsalicylic acid) is derived from traditional medicinal plants, such as cashew nuts, and has been linked to anticancer, anti-inflammatory, and radiosensitization activities through a mechanism that is not yet fully understood. Because of the role of nuclear factor-κB (NF-κB) activation in these cellular responses, we postulated that anacardic acid might interfere with this pathway. We found that this salicylic acid potentiated the apoptosis induced by cytokine and chemotherapeutic agents, which correlated with the down-regulation of various gene products that mediate proliferation (cyclin D1 and cyclooxygenase-2), survival (Bcl-2, Bcl-xL, cFLIP, cIAP-1, and survivin), invasion (matrix metalloproteinase-9 and intercellular adhesion molecule-1), and angiogenesis (vascular endothelial growth factor), all known to be regulated by the NF-κB. We found that anacardic acid inhibited both inducible and constitutive NF-κB activation; suppressed the activation of IκBα kinase that led to abrogation of phosphorylation and degradation of IκBα; inhibited acetylation and nuclear translocation of p65; and suppressed NF-κB–dependent reporter gene expression. Down-regulation of the p300 histone acetyltransferase gene by RNA interference abrogated the effect of anacardic acid on NF-κB suppression, suggesting the critical role of this enzyme. Overall, our results demonstrate a novel role for anacardic acid in potentially preventing or treating cancer through modulation of NF-κB signaling pathway. PMID:18349320

  3. Structural and Functional Evidence for Bacillus subtilis PaiA as a Novel N1-spermidine/spermine acetyltransferase (SSAT)

    SciTech Connect

    Forouhar,F.; Lee, I.; Vujcic, J.; Vujcic, S.; Shen, J.; Vorobiev, S.; Xiao, R.; Acton, T.; Montelione, G.; et al.

    2005-01-01

    Bacillus subtilis PaiA has been implicated in the negative control of sporulation as well as production of degradative enzymes. PaiA shares recognizable sequence homology with N-acetyltransferases, including those that can acetylate spermidine/spermine substrates (SSATs). We have determined the crystal structure of PaiA in complex with CoA at 1.9 Angstrom resolution and found that PaiA is a member of the N-acetyltransferase superfamily of enzymes. Unexpectedly, we observed the binding of an oxidized CoA dimer in the active site of PaiA, and the structural information suggests the substrates of the enzyme could be linear, positively charged compounds. Our biochemical characterization is also consistent with this possibility since purified PaiA possesses N1-acetyltransferase activity towards polyamine substrates including spermidine and spermine. Further, conditional over-expression of PaiA in bacteria results in increased acetylation of endogenous spermidine pools. Thus, our structural and biochemical analyses indicate that PaiA is a novel N-acetyltransferase capable of acetylating both spermidine and spermine. In this way, the pai operon may function in regulating intracellular polyamine concentrations and/or binding capabilities. In addition to preventing toxicity due to polyamine excess, this function may also serve to regulate expression of certain bacterial gene products such as those involved in sporulation.

  4. Global Profiling of Acetyltransferase Feedback Regulation.

    PubMed

    Montgomery, David C; Garlick, Julie M; Kulkarni, Rhushikesh A; Kennedy, Steven; Allali-Hassani, Abdellah; Kuo, Yin-Ming; Andrews, Andrew J; Wu, Hong; Vedadi, Masoud; Meier, Jordan L

    2016-05-25

    Lysine acetyltransferases (KATs) are key mediators of cell signaling. Methods capable of providing new insights into their regulation thus constitute an important goal. Here we report an optimized platform for profiling KAT-ligand interactions in complex proteomes using inhibitor-functionalized capture resins. This approach greatly expands the scope of KATs, KAT complexes, and CoA-dependent enzymes accessible to chemoproteomic methods. This enhanced profiling platform is then applied in the most comprehensive analysis to date of KAT inhibition by the feedback metabolite CoA. Our studies reveal that members of the KAT superfamily possess a spectrum of sensitivity to CoA and highlight NAT10 as a novel KAT that may be susceptible to metabolic feedback inhibition. This platform provides a powerful tool to define the potency and selectivity of reversible stimuli, such as small molecules and metabolites, that regulate KAT-dependent signaling. PMID:27149119

  5. The Functional Analysis of Histone Acetyltransferase MOF in Tumorigenesis

    PubMed Central

    Su, Jiaming; Wang, Fei; Cai, Yong; Jin, Jingji

    2016-01-01

    Changes in chromatin structure and heritably regulating the gene expression by epigenetic mechanisms, such as histone post-translational modification, are involved in most cellular biological processes. Thus, abnormal regulation of epigenetics is implicated in the occurrence of various diseases, including cancer. Human MOF (males absent on the first) is a member of the MYST (Moz-Ybf2/Sas3-Sas2-Tip60) family of histone acetyltransferases (HATs). As a catalytic subunit, MOF can form at least two distinct multiprotein complexes (MSL and NSL) in human cells. Both complexes can acetylate histone H4 at lysine 16 (H4K16); however, the NSL complex possesses broader substrate specificity and can also acetylate histone H4 at lysines 5 and 8 (H4K5 and H4K8), suggesting the complexity of the intracellular functions of MOF. Silencing of MOF in cells leads to genomic instability, inactivation of gene transcription, defective DNA damage repair and early embryonic lethality. Unbalanced MOF expression and its corresponding acetylation of H4K16 have been found in certain primary cancer tissues, including breast cancer, medulloblastoma, ovarian cancer, renal cell carcinoma, colorectal carcinoma, gastric cancer, as well as non-small cell lung cancer. In this review, we provide a brief overview of MOF and its corresponding histone acetylation, introduce recent research findings that link MOF functions to tumorigenesis and speculate on the potential role that may be relevant to tumorigenic pathways. PMID:26784169

  6. N-acetyltransferase 2 activity and folate levels

    PubMed Central

    Cao, Wen; Strnatka, Diana; McQueen, Charlene A.; Hunter, Robert J.; Erickson, Robert P.

    2010-01-01

    Aims To determine whether increased N-acetyltransferase (NAT) activity might have a toxic effect during development and an influence on folate levels since previous work has shown that only low levels of exogenous NAT can be achieved in constitutionally transgenic mice (Cao, et al, 2005) Main Methods A human NAT1 tet-inducible construct was used that would not be expressed until the inducer was delivered. Human NAT1 cDNA was cloned into pTRE2 and injected into mouse oocytes. Two transgenic lines were crossed to mouse line TgN(rtTahCMV)4Uh containing the CMV promoted “teton.”Measurements of red blood cell folate levels in inbred strains of mice were performed. Key findings Only low levels of human NAT1 could be achieved in kidney (highly responsive in other studies) whether the inducer, doxycycline, was given by gavage or in drinking water.An inverse correlation of folate levels with Nat2 enzyme activity was found. Significance Since increasing NAT1 activity decrease folate in at least one tissue, the detrimental effect of expression of human NAT1 in combination with endogenous mouse Nat2 may be a consequence of increased catabolism of folate. PMID:19932120

  7. The Functional Analysis of Histone Acetyltransferase MOF in Tumorigenesis.

    PubMed

    Su, Jiaming; Wang, Fei; Cai, Yong; Jin, Jingji

    2016-01-01

    Changes in chromatin structure and heritably regulating the gene expression by epigenetic mechanisms, such as histone post-translational modification, are involved in most cellular biological processes. Thus, abnormal regulation of epigenetics is implicated in the occurrence of various diseases, including cancer. Human MOF (males absent on the first) is a member of the MYST (Moz-Ybf2/Sas3-Sas2-Tip60) family of histone acetyltransferases (HATs). As a catalytic subunit, MOF can form at least two distinct multiprotein complexes (MSL and NSL) in human cells. Both complexes can acetylate histone H4 at lysine 16 (H4K16); however, the NSL complex possesses broader substrate specificity and can also acetylate histone H4 at lysines 5 and 8 (H4K5 and H4K8), suggesting the complexity of the intracellular functions of MOF. Silencing of MOF in cells leads to genomic instability, inactivation of gene transcription, defective DNA damage repair and early embryonic lethality. Unbalanced MOF expression and its corresponding acetylation of H4K16 have been found in certain primary cancer tissues, including breast cancer, medulloblastoma, ovarian cancer, renal cell carcinoma, colorectal carcinoma, gastric cancer, as well as non-small cell lung cancer. In this review, we provide a brief overview of MOF and its corresponding histone acetylation, introduce recent research findings that link MOF functions to tumorigenesis and speculate on the potential role that may be relevant to tumorigenic pathways. PMID:26784169

  8. Chat reference service in medical libraries: part 2--Trends in medical school libraries.

    PubMed

    Dee, Cheryl R

    2003-01-01

    An increasing number of medical school libraries offer chat service to provide immediate, high quality information at the time and point of need to students, faculty, staff, and health care professionals. Part 2 of Chat Reference Service in Medical Libraries presents a snapshot of the current trends in chat reference service in medical school libraries. In late 2002, 25 (21%) medical school libraries provided chat reference. Trends in chat reference services in medical school libraries were compiled from an exploration of medical school library Web sites and informal correspondence from medical school library personnel. Many medical libraries are actively investigating and planning new chat reference services, while others have decided not to pursue chat reference at this time. Anecdotal comments from medical school library staff provide insights into chat reference service. PMID:12723811

  9. Communication Strategy Use and Negotiation of Meaning in Text Chat and Videoconferencing

    ERIC Educational Resources Information Center

    Zhao, Ying

    2010-01-01

    This study aims at investigating meaning negotiation and communication strategy use among nonnative speakers of English in text chat and videoconferencing. Learners in a Chinese and a Japanese university participated in text chats and videoconferences to discuss culture-related topics using English as the common language. Text chat scripts and…

  10. Opinions of Female Juvenile Delinquents about Their Interactions in Chat Rooms

    ERIC Educational Resources Information Center

    Sanger, Dixie; Long, Amie; Ritzman, Mitzi; Stofer, Keri; Davis, Candy

    2004-01-01

    The purpose of this study was to survey the opinions of 62 adolescent females residing in a correctional facility about their use of the Internet to participate in chat room conversations. Findings indicated that 54 of 62 girls (87.09%), with a mean age of 16.72 years, participated in chat room interactions. Most (n = 47) interacted in chat rooms…

  11. Reviving a Digital Dinosaur: Text-Only Synchronous Online Chats and Peer Tutoring in Communication Centers

    ERIC Educational Resources Information Center

    Schwartzman, Roy

    2013-01-01

    A qualitative and quantitative content analysis was conducted of all text-based synchronous online chats at an oral communication peer tutoring center throughout a semester. As a comparative benchmark, chats at the same university's main library were analyzed over the same time period. The library's chats were much more heavily weighted…

  12. Transcription and the New Functionalism: A Counterproposal to CHILDES' CHAT Conventions.

    ERIC Educational Resources Information Center

    Edwards, Jane A.

    The CHAT transcription standard of the Child Language Data Exchange System (CHILDES), the world's largest computer archive of child language data, is critiqued. CHAT is being considered as a possible standard for the field of child language as a whole. It is argued that CHAT is biased toward three views that are no longer current in the field: (1)…

  13. Online Chat Dependency: The Influence of Social Anxiety

    NASA Astrophysics Data System (ADS)

    Wang, Chih-Chien; Chang, Shu-Chen

    Recent developments in information technology have made it easy for people to “chat” online with others in real time, and many do so regularly. “Virtual” relationships can be attractive, especially for people with social interaction problems in the “real world”. This study examines the influence on online chat dependency of three dimensions of social anxiety: general social situation fear, negative evaluation fear, and novel social situation fear. Participants of this study were 454 college students. The survey results show that negative evaluation fear and general social situation fear are relative to online chat dependency, while novel social situation fear does not seem to be a relevant factor.

  14. Small molecule modulators of histone acetyltransferase p300.

    PubMed

    Balasubramanyam, Karanam; Swaminathan, V; Ranganathan, Anupama; Kundu, Tapas K

    2003-05-23

    Histone acetyltransferases (HATs) are a group of enzymes that play a significant role in the regulation of gene expression. These enzymes covalently modify the N-terminal lysine residues of histones by the addition of acetyl groups from acetyl-CoA. Dysfunction of these enzymes is often associated with the manifestation of several diseases, predominantly cancer. Here we report that anacardic acid from cashew nut shell liquid is a potent inhibitor of p300 and p300/CBP-associated factor histone acetyltranferase activities. Although it does not affect DNA transcription, HAT-dependent transcription from a chromatin template was strongly inhibited by anacardic acid. Furthermore, we describe the design and synthesis of an amide derivative N-(4-chloro-3-trifluoromethyl-phenyl)-2-ethoxy-6-pentadecyl-benzamide (CTPB) using anacardic acid as a synthon, which remarkably activates p300 HAT activity but not that of p300/CBP-associated factor. Although CTPB does not affect DNA transcription, it enhances the p300 HAT-dependent transcriptional activation from in vitro assembled chromatin template. However, it has no effect on histone deacetylase activity. These compounds would be useful as biological switching molecules for probing into the role of p300 in transcriptional studies and may also be useful as new chemical entities for the development of anticancer drugs. PMID:12624111

  15. A regulatory cascade involving AarG, a putative sensor kinase, controls the expression of the 2'-N-acetyltransferase and an intrinsic multiple antibiotic resistance (Mar) response in Providencia stuartii.

    PubMed

    Rather, P N; Paradise, M R; Parojcic, M M; Patel, S

    1998-06-01

    A recessive mutation, aarG1, has been identified that resulted in an 18-fold increase in the expression of beta-galactosidase from an aac(2')-lacZ fusion. Transcriptional fusions and Northern blot analysis demonstrated that the aarG1 allele also resulted in a large increase in the expression of aarP, a gene encoding a transcriptional activator of aac(2')-Ia. The effects of aarG1 on aac(2')-Ia expression were mediated by aarP-dependent and -independent mechanisms. The aarG1 allele also resulted in a multiple antibiotic resistance (Mar) phenotype, which included increased chloramphenicol, tetracycline and fluoroquinolone resistance. This Mar phenotype also resulted from aarP-dependent and -independent mechanisms. Sequence analysis of the aarG locus revealed the presence of two open reading frames, designated aarR and aarG, organized in tandem. The putative AarR protein displayed 75% amino acid identity to the response regulator PhoP, and the AarG protein displayed 57% amino acid identity to the sensor kinase PhoQ. The aarG1 mutation, a C to T substitution, resulted in a threonine to isoleucine substitution at position 279 (T279I) in the putative sensor kinase. The AarG product was functionally similar to PhoQ, as it was able to restore wild-type levels of maganin resistance to a Salmonella typhimurium phoQ mutant. However, expression of the aarP and aac(2')-Ia genes was not significantly affected by the levels of Mg2+ or Ca2+, suggesting that aarG senses a signal other than divalent cations. PMID:9680222

  16. Cognitive functioning in children with typical cri du chat (5p-) syndrome.

    PubMed

    Cornish, K M; Bramble, D; Munir, F; Pigram, J

    1999-04-01

    This study is the first attempt to assess systematically the cognitive functioning in children diagnosed with typical cri du chat syndrome (CDCS) using neuropsychological test measures. Twenty-six children aged between 6 years 4 months and 15 years 5 months (mean 8 years 3 months) completed a battery of tasks measuring IQ level, receptive and expressive language skills, and articulation. Twenty-four children were in the severe learning-disability range with no specific verbal or performance profile. Using more finely tuned measures of cognition, however, a clear discrepancy in the pattern of language functioning was found with better receptive than expressive language skills. One implication of these findings is that parents and professionals should be more optimistic about the capacities of children with CDCS to understand more complex verbal commands than their expressive language skills would suggest. PMID:10355811

  17. Energy Matters: An Invitation to Chat About Clean Tech Markets

    ScienceCinema

    Kauffman, Richard

    2013-05-29

    Do you have questions or ideas about how the U.S. Department of Energy can better move renewable energy technologies from labs to the market, to successful full-scale deployment? Richard Kauffman, newly appointed Senior Advisor to Energy Secretary Steven Chu, and former CEO of Good Energies would like to hear them. **LIVE CHAT EXPIRED**

  18. Interaction Management Strategies on IRC and Virtual Chat Rooms.

    ERIC Educational Resources Information Center

    Altun, Arif

    Internet Relay Chat (IRC) is an electronic medium that combines orthographic form with real time, synchronous transmission in an unregulated global multi-user environment. The orthographic letters mediate the interaction in that users can only access the IRC session through reading and writing; they have no access to any visual representations at…

  19. Energy Matters: An invitation to Chat About Industrial Efficiency

    SciTech Connect

    Hogan, Kathleen

    2011-01-01

    Do you have questions or ideas about how the U.S. Department of Energy can contribute to global competitiveness through industrial efficiency? Dr. Kathleen Hogan would like to hear them. Submit your questions via: Email ( newmedia@hq.doe.gov ) Twitter ( @Energy ) Facebook ( Facebook.com/Energygov ) **LIVE CHAT IS EXPIRED**

  20. Energy Matters: An invitation to Chat About Industrial Efficiency

    ScienceCinema

    Hogan, Kathleen

    2013-05-29

    Do you have questions or ideas about how the U.S. Department of Energy can contribute to global competitiveness through industrial efficiency? Dr. Kathleen Hogan would like to hear them. Submit your questions via: Email ( newmedia@hq.doe.gov ) Twitter ( @Energy ) Facebook ( Facebook.com/Energygov ) **LIVE CHAT IS EXPIRED**

  1. Astronaut Thagard and fellow Mir 18 crewmembers chat at JSC

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Astronaut Norman E. Thagard, right, chats with two Russian cosmonauts with whom he will be launched into space early next year for a three month mission. Designated Mir 18, the mission aboard the Russian space station will include Mir 18 crew members Genn

  2. Energy Matters: An Invitation to Chat About Clean Tech Markets

    SciTech Connect

    Kauffman, Richard

    2011-01-01

    Do you have questions or ideas about how the U.S. Department of Energy can better move renewable energy technologies from labs to the market, to successful full-scale deployment? Richard Kauffman, newly appointed Senior Advisor to Energy Secretary Steven Chu, and former CEO of Good Energies would like to hear them. **LIVE CHAT EXPIRED**

  3. Metaphors of Synchrony: Emergence and Differentiation of Online Chat Devices

    ERIC Educational Resources Information Center

    Latzko-Toth, Guillaume

    2010-01-01

    Through a detailed account of the history of online chat devices, this article shows the emergence, over time, of two distinct interactional formats underlying these social media. They may be captured by two generic metaphors of synchrony: "conference" (a gathering in a virtual place where unfocused interactions and group sociability occur) and…

  4. Cyan fluorescent protein expression in ganglion and amacrine cells in a thy1-CFP transgenic mouse retina

    PubMed Central

    Vila, Alejandro; Huynh, Uyen-Chi N.; Brecha, Nicholas C.

    2008-01-01

    Purpose To characterize cyan fluorescent protein (CFP) expression in the retina of the thy1-CFP (B6.Cg-Tg(Thy1-CFP)23Jrs/J) transgenic mouse line. Methods CFP expression was characterized using morphometric methods and immunohistochemistry with antibodies to neurofilament light (NF-L), neuronal nuclei (NeuN), POU-domain protein (Brn3a) and calretinin, which immunolabel ganglion cells, and syntaxin 1 (HPC-1), glutamate decarboxylase 67 (GAD67), GABA plasma membrane transporter-1 (GAT-1), and choline acetyltransferase (ChAT), which immunolabel amacrine cells. Results CFP was extensively expressed in the inner retina, primarily in the inner plexiform layer (IPL), ganglion cell layer (GCL), nerve fiber layer, and optic nerve. CFP fluorescent cell bodies were in all retinal regions and their processes ramified in all laminae of the IPL. Some small, weakly CFP fluorescent somata were in the inner nuclear layer (INL). CFP-containing somata in the GCL ranged from 6 to 20 μm in diameter, and they had a density of 2636±347 cells/mm2 at 1.5 mm from the optic nerve head. Immunohistochemical studies demonstrated colocalization of CFP with the ganglion cell markers NF-L, NeuN, Brn3a, and calretinin. Immunohistochemistry with antibodies to HPC-1, GAD67, GAT-1, and ChAT indicated that the small, weakly fluorescent CFP cells in the INL and GCL were cholinergic amacrine cells. Conclusions The total number and density of CFP-fluorescent cells in the GCL were within the range of previous estimates of the total number of ganglion cells in the C57BL/6J line. Together these findings suggest that most ganglion cells in the thy1-CFP mouse line 23 express CFP. In conclusion, the thy1-CFP mouse line is highly useful for studies requiring the identification of ganglion cells. PMID:18728756

  5. Autoacetylation of the Histone Acetyltransferase Rtt109*

    PubMed Central

    Albaugh, Brittany N.; Arnold, Kevin M.; Lee, Susan; Denu, John M.

    2011-01-01

    Rtt109 is a yeast histone acetyltransferase (HAT) that associates with histone chaperones Asf1 and Vps75 to acetylate H3K56, H3K9, and H3K27 and is important in DNA replication and maintaining genomic integrity. Recently, mass spectrometry and structural studies of Rtt109 have shown that active site residue Lys-290 is acetylated. However, the functional role of this modification and how the acetyl group is added to Lys-290 was unclear. Here, we examined the mechanism of Lys-290 acetylation and found that Rtt109 catalyzes intramolecular autoacetylation of Lys-290 ∼200-times slower than H3 acetylation. Deacetylated Rtt109 was prepared by reacting with a sirtuin protein deacetylase, producing an enzyme with negligible HAT activity. Autoacetylation of Rtt109 restored full HAT activity, indicating that autoacetylation is necessary for HAT activity and is a fully reversible process. To dissect the mechanism of activation, biochemical, and kinetic analyses were performed with Lys-290 variants of the Rtt109-Vps75 complex. We found that autoacetylation of Lys-290 increases the binding affinity for acetyl-CoA and enhances the rate of acetyl-transfer onto histone substrates. This study represents the first detailed investigation of a HAT enzyme regulated by single-site intramolecular autoacetylation. PMID:21606491

  6. Characterization and transcriptional regulation of the 2'-N-acetyltransferase gene from Providencia stuartii.

    PubMed Central

    Rather, P N; Orosz, E; Shaw, K J; Hare, R; Miller, G

    1993-01-01

    We have cloned the chromosomally encoded 2'-N-acetyltransferase gene [aac(2')-Ia] from Providencia stuartii. DNA sequence analysis of the cloned insert identified a single open reading frame, which is capable of encoding a protein with a predicted molecular mass of 20,073 Da. The deduced AAC(2')-Ia protein showed no significant homology to other proteins, including all of the AAC(3) and AAC(6') proteins. Primer extension analysis was used to identify the aac(2')-Ia promoter, which contained an unusual sequence (CTTTTT) at the -35 region. Expression of the aac(2')-Ia gene occurs at low levels in wild-type P. stuartii strains; therefore, they are aminoglycoside susceptible. We have isolated mutants with high-level AAC(2')-Ia expression at a frequency of 4.8 x 10(-6). Detailed analysis of one mutant demonstrated a 12.2-fold increase in the accumulation of aac(2')-Ia mRNA. In addition, the levels of beta-galactosidase expression from a plasmid-encoded aac(2')-lacZ transcriptional fusion were increased 11.5-fold in this mutant relative to those in an isogenic wild-type strain. These results suggested that a trans-acting factor, designated aar (for aminoglycoside acetyltransferase regulator), controls AAC(2')-Ia expression in P. stuartii. Images PMID:8407825

  7. An exploratory study of Internet-initiated sexual offenses and the chat room sex offender: has the Internet enabled a new typology of sex offender?

    PubMed

    Briggs, Peter; Simon, Walter T; Simonsen, Stacy

    2011-03-01

    This exploratory study examined 51 participants convicted of an Internet-initiated sex offense in which they attempted to entice an adolescent into a sexual relationship using an Internet chat room. All participants were convicted of a sex offense and subject to an evaluation as a part of sentencing requirements in Colorado. Clinical and behavioral data were obtained from each subject's offense-specific evaluation and chat room transcripts. The results of the study found that 90% of the participants were apprehended as a result of an Internet sex sting. The authors conclude that Internet chat room sex offenders constitute a separate group characterized by less severe criminogenic factors than other sex offenders (rapists, child molesters). It can be hypothesized that chat room sex offenders avoid relationships and spend a significant amount of time in online chat rooms as a primary social and sexual outlet, and engage in other sexually compulsive behaviors. Within this offender group, it was discovered that two subgroups exist: a contact-driven group motivated to engage in offline sexual behavior with an adolescent and a fantasy-driven group motivated to engage an adolescent in online cybersex without an express intent to meet offline. The chat room sex offender presents a significant clinical issue to treatment providers as a live victim does not exist. Thus, it is unclear if Internet sex stings prevent incidents of child sexual exploitation and may result in convictions of individuals who may never have abused a child. The data suggest a tentative sex offender typology, including subtypes, which need to be replicated in future studies. PMID:20947699

  8. The distribution and morphological characteristics of cholinergic cells in the brain of monotremes as revealed by ChAT immunohistochemistry.

    PubMed

    Manger, P R; Fahringer, H M; Pettigrew, J D; Siegel, J M

    2002-01-01

    The present study employs choline acetyltransferase (ChAT) immunohistochemistry to identify the cholinergic neuronal population in the central nervous system of the monotremes. Two of the three extant species of monotreme were studied: the platypus (Ornithorhynchus anatinus) and the short-beaked echidna (Tachyglossus aculeatus). The distribution of cholinergic cells in the brain of these two species was virtually identical. Distinct groups of cholinergic cells were observed in the striatum, basal forebrain, habenula, pontomesencephalon, cranial nerve motor nuclei, and spinal cord. In contrast to other tetrapods studied with this technique, we failed to find evidence for cholinergic cells in the hypothalamus, the parabigeminal nucleus (or nucleus isthmus), or the cerebral cortex. The lack of hypothalamic cholinergic neurons creates a hiatus in the continuous antero-posterior aggregation of cholinergic neurons seen in other tetrapods. This hiatus might be functionally related to the phenomenology of monotreme sleep and to the ontogeny of sleep in mammals, as juvenile placental mammals exhibit a similar combination of sleep elements to that found in adult monotremes. PMID:12476054

  9. The identification of five novel genes in the cri-du-chat critical region

    SciTech Connect

    Simmons, A.D.; Gallardo, T.D.; Lovett, M.

    1994-09-01

    Cri-du-chat is a contiguous gene syndrome associated with deletions in the short arm of chromosome 5 (chr 5). Chr 5p-specific markers have been used to define two critical regions: a larynx malformation region, located at 5p15.3, and a region responsible for the remaining clinical features of the syndrome, which maps to 5p15.2. Thirty cosmids that map to this latter region have been isolated from the LANL chr 5-specific library using 5 STSs. More recently, we have constructed a YAC contig of the region which encompasses 2-3 Mb. The 30 framework cosmids were used in a direct selection with cDNAs from placenta, activated T-cells and cerebellum to isolate an initial set of expressed sequences from this region. Since no genes, to date, have been isolated or localized within the cri-du-chat deletion, a cosmid containing a control reporter gene (ANX6) was used to monitor enrichment. ANX6 cDNAs were enriched by several thousand-fold in the selected cDNAs. A total of nine non overlapping cDNA fragments were obtained from the cDNA pools. These have been ordered within the YAC contig, map to 5 discrete cosmid sets in the critical region and thus conservatively represent five discrete transcription units. The DNA sequences of these fragments are novel by sequence database comparisons. PCR primers were constructed and were used to confirm gene placements in the YAC contig, as well as to investigate the expression profile of these genes in several different tissues and cell types. In one case, these primer sets enabled two of the nine fragments to be linked into a larger cDNA. The nine cDNAs showed various patterns of differential expression in a panel of tissues. These expressed sequences represent the first genes isolated within the cri-du-chat critical region and represent the initial steps in the derivation of a comprehensive inventory and expression profile of the estimated 100 genes that may reside in this region.

  10. N-palmitoyl serotonin alleviates scopolamine-induced memory impairment via regulation of cholinergic and antioxidant systems, and expression of BDNF and p-CREB in mice.

    PubMed

    Min, A Young; Doo, Choon Nan; Son, Eun Jung; Sung, Nak Yun; Lee, Kun Jong; Sok, Dai-Eun; Kim, Mee Ree

    2015-12-01

    N-Palmitoyl-5-hydroxytryptamines (Pal-5HT), a cannabinoid, has recently been reported to express anti-allergic and anti-inflammatory actions in RBL-2H3 cells, and ameliorate glutamate-induced cytotoxicity in HT-22 cells. In this study, we examined the effect of Pal-5HT on deficits of learning and memory induced by scopolamine in mice. Memory performance was evaluated using Morris water maze test and passive avoidance test. Activities of acetylcholinesterase (AChE) and choline acetyltransferase (ChAT), level of oxidative stress markers, and expression of brain-derived neurotrophic factor (BDNF), phosphorylation of cAMP response element-binding protein (p-CREB) were determined. Loss of neuronal cells in hippocampus was evaluated by histological examinations. Pal-5HT significantly improved the amnesia in the behavioral assessment. Pal-5HT regulated cholinergic function by inhibiting scopolamine-induced elevation of AChE activity and decline of ChAT activity. Pal-5HT suppressed oxidative stress by increasing activities of glutathione peroxidase (GPx), glutathione reductase (GR) or NAD(P)H quinine oxidoreductase-1 (NQO-1) and lowering MDA level. Additionally, it prevented against scopolamine-induced expression of iNOS and COX-2. Moreover, Pal-5HT suppressed the death of neuronal cells in CA1 and CA3 regions, while it restored expression of p-CREB and BDNF in hippocampus. Taken together, Pal-5HT is suggested to ameliorate deficits of memory and learning through regulation of cholinergic function, activation of antioxidant systems as well as restoration of BDNF and p-CREB expression. From these, Pal-5HT may be a potential candidate to prevent against neurodegeneration related to the memory deficit. PMID:26408985

  11. Human NAT10 Is an ATP-dependent RNA Acetyltransferase Responsible for N4-Acetylcytidine Formation in 18 S Ribosomal RNA (rRNA)*

    PubMed Central

    Ito, Satoshi; Horikawa, Sayuri; Suzuki, Tateki; Kawauchi, Hiroki; Tanaka, Yoshikazu; Suzuki, Takeo; Suzuki, Tsutomu

    2014-01-01

    Human N-acetyltransferase 10 (NAT10) is known to be a lysine acetyltransferase that targets microtubules and histones and plays an important role in cell division. NAT10 is highly expressed in malignant tumors, and is also a promising target for therapies against laminopathies and premature aging. Here we report that NAT10 is an ATP-dependent RNA acetyltransferase responsible for formation of N4-acetylcytidine (ac4C) at position 1842 in the terminal helix of mammalian 18 S rRNA. RNAi-mediated knockdown of NAT10 resulted in growth retardation of human cells, and this was accompanied by high-level accumulation of the 30 S precursor of 18 S rRNA, suggesting that ac4C1842 formation catalyzed by NAT10 is involved in rRNA processing and ribosome biogenesis. PMID:25411247

  12. Structure of a putative acetyltransferase (PA1377) from Pseudomonas aeruginosa

    SciTech Connect

    Davies, Anna M.; Tata, Renée; Chauviac, François-Xavier; Sutton, Brian J.; Brown, Paul R.

    2008-05-01

    The crystal structure of an acetyltransferase encoded by the gene PA1377 from Pseudomonas aeruginosa has been determined at 2.25 Å resolution. Comparison with a related acetyltransferase revealed a structural difference in the active site that was taken to reflect a difference in substrate binding and/or specificity between the two enzymes. Gene PA1377 from Pseudomonas aeruginosa encodes a 177-amino-acid conserved hypothetical protein of unknown function. The structure of this protein (termed pitax) has been solved in space group I222 to 2.25 Å resolution. Pitax belongs to the GCN5-related N-acetyltransferase family and contains all four sequence motifs conserved among family members. The β-strand structure in one of these motifs (motif A) is disrupted, which is believed to affect binding of the substrate that accepts the acetyl group from acetyl-CoA.

  13. GABAergic neurons of the laterodorsal and pedunculopontine tegmental nuclei of the cat express c-fos during carbachol-induced active sleep.

    PubMed

    Torterolo, P; Yamuy, J; Sampogna, S; Morales, F R; Chase, M H

    2001-02-23

    The laterodorsal and pedunculopontine tegmental nuclei (LDT-PPT) are involved in the generation of active sleep (AS; also called REM or rapid eye movement sleep). Although the LDT-PPT are composed principally of cholinergic neurons that participate in the control of sleep and waking states, the function of the large number of GABAergic neurons that are also located in the LDT-PPT is unknown. Consequently, we sought to determine if these neurons are activated (as indicated by their c-fos expression) during active sleep induced by the microinjection of carbachol into the rostro-dorsal pons (AS-carbachol). Accordingly, immunocytochemical double-labeling techniques were used to identify GABA and Fos protein, as well as choline acetyltransferase (ChAT), in histological sections of the LDT-PPT. Compared to control awake cats, there was a larger number of GABAergic neurons that expressed c-fos during AS-carbachol (31.5+/-6.1 vs. 112+/-15.2, P<0.005). This increase in the number of GABA+Fos+ neurons occurred on the ipsilateral side relative to the injection site; there was a small decrease in GABA+Fos+ cells in the contralateral LDT-PPT. However, the LDT-PPT neurons that exhibited the largest increase in c-fos expression during AS-carbachol were neither GABA+ nor ChAT+ (47+/-22.5 vs. 228.7+/-14.0, P<0.0005). The number of cholinergic neurons that expressed c-fos during AS-carbachol was not significantly different compared to wakefulness. These data demonstrate that, during AS-carbachol, GABAergic as well as an unidentified population of neurons are activated in the LDT-PPT. We propose that these non-cholinergic LDT-PPT neurons may participate in the regulation of active sleep. PMID:11172778

  14. Location based chat application for iPhone

    NASA Astrophysics Data System (ADS)

    Rana, Pradeep

    With the increasing use of mobile devices everywhere in the world, there is a lack of social interaction between people. The objective of this thesis project is to create a location based chat application, which will help users to interact with other people around them. It will provide an opportunity to meet people when someone visits a new place. The app will use GPS coordinates of the user and will show him a list of other users based on his location. The user can then choose any of the other users from the list and start chatting with them. This app will consist of a frontend and backend. The frontend will be an iOS application and the backend will be a PHP/MYSQL server.

  15. Astronaut Jean-Francois Clervoy chats with STS-66 crewmates

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Astronaut Jean-Francois Clervoy (center), STS-66 international mission specialist, chats with payload crew mates during a training session on emergency egress procedures. Wearing training versions of the launch and entry suits, the crew members are, left to right, Scott E. Parazynski, Joseph P. Tanner, Clervoy and Ellen Ochoa. Ochoa is the payload commander, Tanner and Parazynski are NASA mission specialists and Clervoy represents the European Space Agency (ESA) as a mission specialist.

  16. Choline acetyltransferase-like immunoreactivity in a physiologically distinct subtype of olfactory nonspiking local interneurons in the cockroach (periplaneta americana).

    PubMed

    Fusca, Debora; Husch, Andreas; Baumann, Arnd; Kloppenburg, Peter

    2013-10-15

    Behavioral and physiological studies have shown that local interneurons are pivotal for processing odor information in the insect antennal lobe. They mediate inhibitory and excitatory interactions between the glomerular pathways and ultimately shape the tuning profile of projection neurons. To identify putative cholinergic local interneurons in the antennal lobe of Periplaneta americana, an antibody raised against the biosynthetic enzyme choline acetyltransferase (ChAT) was applied to individual morphologically and electrophysiologically characterized local interneurons. In nonspiking type IIa1 local interneurons, which were classified in this study, we found ChAT-like immunoreactivity suggesting that they are most likely excitatory. This is a well-defined population of neurons that generates Ca(2+) -driven spikelets upon depolarization and stimulation with odorants, but not Na(+) -driven action potentials, because they lack voltage-activated transient Na(+) currents. The nonspiking type IIa2 and type IIb local interneurons, in which Ca(2+) -driven spikelets were absent, had no ChAT-like immunoreactivity. The GABA-like immunoreactive, spiking type I local interneurons had no ChAT-like immunoreactivity. In addition, we showed that uniglomerular projection neurons with cell bodies located in the ventral portion of the ventrolateral somata group and projections along the inner antennocerebral tract exhibited ChAT-like immunoreactivity. Assigning potential transmitters and neuromodulators to distinct morphological and electrophysiological types of antennal lobe neurons is an important prerequisite for a detailed understanding of odor information processing in insects. PMID:23749599

  17. A Cooperative Human-Adaptive Traffic Simulation (CHATS)

    NASA Technical Reports Server (NTRS)

    Phillips, Charles T.; Ballin, Mark G.

    1999-01-01

    NASA is considering the development of a Cooperative Human-Adaptive Traffic Simulation (CHATS), to examine and evaluate performance of the National Airspace System (NAS) as the aviation community moves toward free flight. CHATS will be specifically oriented toward simulating strategic decision-making by airspace users and by the service provider s traffic management personnel, within the context of different airspace and rules assumptions. It will use human teams to represent these interests and make decisions, and will rely on computer modeling and simulation to calculate the impacts of these decisions. The simulation objectives will be to examine: 1. evolution of airspace users and the service provider s strategies, through adaptation to new operational environments; 2. air carriers competitive and cooperative behavior; 3. expected benefits to airspace users and the service provider as compared to the current NAS; 4. operational limitations of free flight concepts due to congestion and safety concerns. This paper describes an operational concept for CHATS, and presents a high-level functional design which would utilize a combination of existing and new models and simulation capabilities.

  18. The N-terminal acetyltransferase Naa10 is essential for zebrafish development

    PubMed Central

    Ree, Rasmus; Myklebust, Line M.; Thiel, Puja; Foyn, Håvard; Fladmark, Kari E.; Arnesen, Thomas

    2015-01-01

    N-terminal acetylation, catalysed by N-terminal acetyltransferases (NATs), is among the most common protein modifications in eukaryotes and involves the transfer of an acetyl group from acetyl-CoA to the α-amino group of the first amino acid. Functions of N-terminal acetylation include protein degradation and sub-cellular targeting. Recent findings in humans indicate that a dysfunctional Nα-acetyltransferase (Naa) 10, the catalytic subunit of NatA, the major NAT, is associated with lethality during infancy. In the present study, we identified the Danio rerio orthologue zebrafish Naa 10 (zNaa10). In vitro N-terminal acetylation assays revealed that zNaa10 has NAT activity with substrate specificity highly similar to that of human Naa10. Spatiotemporal expression pattern was determined by in situ hybridization, showing ubiquitous expression with especially strong staining in brain and eye. By morpholino-mediated knockdown, we demonstrated that naa10 morphants displayed increased lethality, growth retardation and developmental abnormalities like bent axis, abnormal eyes and bent tails. In conclusion, we identified the zebrafish Naa10 orthologue and revealed that it is essential for normal development and viability of zebrafish. PMID:26251455

  19. Improvement of L-citrulline production in Corynebacterium glutamicum by ornithine acetyltransferase.

    PubMed

    Hao, N; Mu, J; Hu, N; Xu, S; Yan, M; Li, Y; Guo, K; Xu, L

    2015-02-01

    In this study, Corynebacterium glutamicum ATCC 13032 was engineered to produce L-citrulline through a metabolic engineering strategy. To prevent the flux away from L-citrulline and to increase the expression levels of genes involved in the citrulline biosynthesis pathway, the argininosuccinate synthase gene (argG) and the repressor gene (argR) were inactivated. The engineered C. glutamicum ATCC 13032 ∆argG ∆argR (CIT 2) produced higher amounts of L-citrulline (5.43 g/L) compared to the wildtype strain (0.15 g/L). To determine new strategies for further enhancement of L-citrulline production, the effect of L-citrulline on ornithine acetyltransferase (EC 2.3.1.35; OATase; ArgJ) was first investigated. Citrulline was determined to inhibit Ornithine acetyltransferase; for 50 % inhibition, citrulline concentration was 30 mM. The argJ gene from C. glutamicum ATCC 13032 was cloned, and the recombinant shuttle plasmid pXMJ19-argJ was constructed and expressed in C. glutamicum ATCC 13032 ∆argG ∆argR (CIT 2). Overexpression of the argJ gene exhibited increased OAT activity and resulted in a positive effect on citrulline production (8.51 g/L). These results indicate that OAT plays a vital role during L-citrulline production in C. glutamicum. PMID:25492493

  20. Mutations in KAT6B, Encoding a Histone Acetyltransferase, Cause Genitopatellar Syndrome

    PubMed Central

    Campeau, Philippe M.; Kim, Jaeseung C.; Lu, James T.; Schwartzentruber, Jeremy A.; Abdul-Rahman, Omar A.; Schlaubitz, Silke; Murdock, David M.; Jiang, Ming-Ming; Lammer, Edward J.; Enns, Gregory M.; Rhead, William J.; Rowland, Jon; Robertson, Stephen P.; Cormier-Daire, Valérie; Bainbridge, Matthew N.; Yang, Xiang-Jiao; Gingras, Marie-Claude; Gibbs, Richard A.; Rosenblatt, David S.; Majewski, Jacek; Lee, Brendan H.

    2012-01-01

    Genitopatellar syndrome (GPS) is a skeletal dysplasia with cerebral and genital anomalies for which the molecular basis has not yet been determined. By exome sequencing, we found de novo heterozygous truncating mutations in KAT6B (lysine acetyltransferase 6B, formerly known as MYST4 and MORF) in three subjects; then by Sanger sequencing of KAT6B, we found similar mutations in three additional subjects. The mutant transcripts do not undergo nonsense-mediated decay in cells from subjects with GPS. In addition, human pathological analyses and mouse expression studies point to systemic roles of KAT6B in controlling organismal growth and development. Myst4 (the mouse orthologous gene) is expressed in mouse tissues corresponding to those affected by GPS. Phenotypic differences and similarities between GPS, the Say-Barber-Biesecker variant of Ohdo syndrome (caused by different mutations of KAT6B), and Rubinstein-Taybi syndrome (caused by mutations in other histone acetyltransferases) are discussed. Together, the data support an epigenetic dysregulation of the limb, brain, and genital developmental programs. PMID:22265014

  1. Mutations in KAT6B, encoding a histone acetyltransferase, cause Genitopatellar syndrome.

    PubMed

    Campeau, Philippe M; Kim, Jaeseung C; Lu, James T; Schwartzentruber, Jeremy A; Abdul-Rahman, Omar A; Schlaubitz, Silke; Murdock, David M; Jiang, Ming-Ming; Lammer, Edward J; Enns, Gregory M; Rhead, William J; Rowland, Jon; Robertson, Stephen P; Cormier-Daire, Valérie; Bainbridge, Matthew N; Yang, Xiang-Jiao; Gingras, Marie-Claude; Gibbs, Richard A; Rosenblatt, David S; Majewski, Jacek; Lee, Brendan H

    2012-02-10

    Genitopatellar syndrome (GPS) is a skeletal dysplasia with cerebral and genital anomalies for which the molecular basis has not yet been determined. By exome sequencing, we found de novo heterozygous truncating mutations in KAT6B (lysine acetyltransferase 6B, formerly known as MYST4 and MORF) in three subjects; then by Sanger sequencing of KAT6B, we found similar mutations in three additional subjects. The mutant transcripts do not undergo nonsense-mediated decay in cells from subjects with GPS. In addition, human pathological analyses and mouse expression studies point to systemic roles of KAT6B in controlling organismal growth and development. Myst4 (the mouse orthologous gene) is expressed in mouse tissues corresponding to those affected by GPS. Phenotypic differences and similarities between GPS, the Say-Barber-Biesecker variant of Ohdo syndrome (caused by different mutations of KAT6B), and Rubinstein-Taybi syndrome (caused by mutations in other histone acetyltransferases) are discussed. Together, the data support an epigenetic dysregulation of the limb, brain, and genital developmental programs. PMID:22265014

  2. CBP histone acetyltransferase activity is a critical component of memory consolidation.

    PubMed

    Korzus, Edward; Rosenfeld, Michael G; Mayford, Mark

    2004-06-24

    The stabilization of learned information into long-term memories requires new gene expression. CREB binding protein (CBP) is a coactivator of transcription that can be independently regulated in neurons. CBP functions both as a platform for recruiting other required components of the transcriptional machinery and as a histone acetyltransferase (HAT) that alters chromatin structure. To dissect the chromatin remodeling versus platform function of CBP or the developmental versus adult role of this gene, we generated transgenic mice that express CBP in which HAT activity is eliminated. Acquisition of new information and short-term memory is spared in these mice, while the stabilization of short-term memory into long-term memory is impaired. The behavioral phenotype is due to an acute requirement for CBP HAT activity in the adult as it is rescued by both suppression of transgene expression or by administration of the histone deacetylase inhibitor Trichostatin A (TSA) in adult animals. PMID:15207240

  3. Structure and Biochemical Characterization of Protein Acetyltransferase from Sulfolobus solfataricus

    SciTech Connect

    Brent, Michael M.; Iwata, Ayaka; Carten, Juliana; Zhao, Kehao; Marmorstein, Ronen

    2009-09-02

    The Sulfolobus solfataricus protein acetyltransferase (PAT) acetylates ALBA, an abundant nonspecific DNA-binding protein, on Lys{sup 16} to reduce its DNA affinity, and the Sir2 deacetylase reverses the modification to cause transcriptional repression. This represents a 'primitive' model for chromatin regulation analogous to histone modification in eukaryotes. We report the 1.84-{angstrom} crystal structure of PAT in complex with coenzyme A. The structure reveals homology to both prokaryotic GNAT acetyltransferases and eukaryotic histone acetyltransferases (HATs), with an additional 'bent helix' proximal to the substrate binding site that might play an autoregulatory function. Investigation of active site mutants suggests that PAT does not use a single general base or acid residue for substrate deprotonation and product reprotonation, respectively, and that a diffusional step, such as substrate binding, may be rate-limiting. The catalytic efficiency of PAT toward ALBA is low relative to other acetyltransferases, suggesting that there may be better, unidentified substrates for PAT. The structural similarity of PAT to eukaryotic HATs combined with its conserved role in chromatin regulation suggests that PAT is evolutionarily related to the eukaryotic HATs.

  4. Spermidine induces autophagy by inhibiting the acetyltransferase EP300

    PubMed Central

    Pietrocola, F; Lachkar, S; Enot, D P; Niso-Santano, M; Bravo-San Pedro, J M; Sica, V; Izzo, V; Maiuri, M C; Madeo, F; Mariño, G; Kroemer, G

    2015-01-01

    Several natural compounds found in health-related food items can inhibit acetyltransferases as they induce autophagy. Here we show that this applies to anacardic acid, curcumin, garcinol and spermidine, all of which reduce the acetylation level of cultured human cells as they induce signs of increased autophagic flux (such as the formation of green fluorescent protein-microtubule-associated protein 1A/1B-light chain 3 (GFP-LC3) puncta and the depletion of sequestosome-1, p62/SQSTM1) coupled to the inhibition of the mammalian target of rapamycin complex 1 (mTORC1). We performed a screen to identify the acetyltransferases whose depletion would activate autophagy and simultaneously inhibit mTORC1. The knockdown of only two acetyltransferases (among 43 candidates) had such effects: EP300 (E1A-binding protein p300), which is a lysine acetyltranferase, and NAA20 (N(α)-acetyltransferase 20, also known as NAT5), which catalyzes the N-terminal acetylation of methionine residues. Subsequent studies validated the capacity of a pharmacological EP300 inhibitor, C646, to induce autophagy in both normal and enucleated cells (cytoplasts), underscoring the capacity of EP300 to repress autophagy by cytoplasmic (non-nuclear) effects. Notably, anacardic acid, curcumin, garcinol and spermidine all inhibited the acetyltransferase activity of recombinant EP300 protein in vitro. Altogether, these results support the idea that EP300 acts as an endogenous repressor of autophagy and that potent autophagy inducers including spermidine de facto act as EP300 inhibitors. PMID:25526088

  5. Epigenetic change in kidney tumor: downregulation of histone acetyltransferase MYST1 in human renal cell carcinoma

    PubMed Central

    2013-01-01

    Background MYST1 (also known as hMOF), a member of the MYST family of histone acetyltransferases (HATs) as an epigenetic mark of active genes, is mainly responsible for histone H4K16 acetylation in the cells. Recent studies have shown that the abnormal gene expression of hMOF is involved in certain primary cancers. Here we examined the involvement of hMOF expression and histone H4K16 acetylation in primary renal cell carcinoma (RCC). Simultaneously, we investigated the correlation between the expression of hMOF and clear cell RCC (ccRCC) biomarker carbohydrase IX (CA9) in RCC. Materials and methods The frozen RCC tissues and RCC cell lines as materials, the reverse transcription polymerase chain reaction (RT-PCR), western blotting and immunohistochemical staining approaches were used. Results RT-PCR results indicate that hMOF gene expression levels frequently downregulated in 90.5% of patients (19/21) with RCC. The reduction of hMOF protein in both RCC tissues and RCC cell lines is tightly correlated with acetylation of histone H4K16. In addition, overexpression of CA9 was detected in 100% of ccRCC patients (21/21). However, transient transfection of hMOF in ccRCC 786–0 cells did not affect both the gene and protein expression of CA9. Conclusion hMOF as an acetyltransferase of H4K16 might be involved in the pathogenesis of kidney cancer, and this epigenetic changes might be a new CA9-independent RCC diagnostic maker. PMID:23394073

  6. Cysteine biosynthesis in Lactobacillus casei: identification and characterization of a serine acetyltransferase.

    PubMed

    Bogicevic, Biljana; Berthoud, Hélène; Portmann, Reto; Bavan, Tharmatha; Meile, Leo; Irmler, Stefan

    2016-02-01

    In bacteria, cysteine can be synthesized from serine by two steps involving an L-serine O-acetyltransferase (SAT) and a cysteine synthase (CysK). While CysK is found in the publicly available annotated genome from Lactobacillus casei ATCC 334, a gene encoding SAT (cysE) is missing. In this study, we found that various strains of L. casei grew in a chemically defined medium containing sulfide as the sole sulfur source, indicating the presence of a serine O-acetyltransferase. The gene lying upstream of cysK is predicted to encode a homoserine trans-succinylase (metA). To study the function of this gene, it was cloned from L. casei FAM18110. The purified, recombinant protein did not acylate L-homoserine in vitro. Instead, it catalyzed the formation of O-acetyl serine from L-serine and acetyl-CoA. Furthermore, the plasmid expressing the L. casei gene complemented an Escherichia coli cysE mutant strain but not an E. coli metA mutant. This clearly demonstrated that the gene annotated as metA in fact encodes the SAT function and should be annotated as cysE. PMID:26790714

  7. Histone acetyltransferase PCAF is required for Hedgehog-Gli-dependent transcription and cancer cell proliferation.

    PubMed

    Malatesta, Martina; Steinhauer, Cornelia; Mohammad, Faizaan; Pandey, Deo P; Squatrito, Massimo; Helin, Kristian

    2013-10-15

    The Hedgehog (Hh) signaling pathway plays an important role in embryonic patterning and development of many tissues and organs as well as in maintaining and repairing mature tissues in adults. Uncontrolled activation of the Hh-Gli pathway has been implicated in developmental abnormalities as well as in several cancers, including brain tumors like medulloblastoma and glioblastoma. Inhibition of aberrant Hh-Gli signaling has, thus, emerged as an attractive approach for anticancer therapy; however, the mechanisms that mediate Hh-Gli signaling in vertebrates remain poorly understood. Here, we show that the histone acetyltransferase PCAF/KAT2B is an important factor of the Hh pathway. Specifically, we show that PCAF depletion impairs Hh activity and reduces expression of Hh target genes. Consequently, PCAF downregulation in medulloblastoma and glioblastoma cells leads to decreased proliferation and increased apoptosis. In addition, we found that PCAF interacts with GLI1, the downstream effector in the Hh-Gli pathway, and that PCAF or GLI1 loss reduces the levels of H3K9 acetylation on Hh target gene promoters. Finally, we observed that PCAF silencing reduces the tumor-forming potential of neural stem cells in vivo. In summary, our study identified the acetyltransferase PCAF as a positive cofactor of the Hh-Gli signaling pathway, leading us to propose PCAF as a candidate therapeutic target for the treatment of patients with medulloblastoma and glioblastoma. PMID:23943798

  8. Cysteine biosynthesis in Lactobacillus casei: identification and characterization of a serine acetyltransferase

    PubMed Central

    Bogicevic, Biljana; Berthoud, Hélène; Portmann, Reto; Bavan, Tharmatha; Meile, Leo; Irmler, Stefan

    2016-01-01

    In bacteria, cysteine can be synthesized from serine by two steps involving an L-serine O-acetyltransferase (SAT) and a cysteine synthase (CysK). While CysK is found in the publicly available annotated genome from Lactobacillus casei ATCC 334, a gene encoding SAT (cysE) is missing. In this study, we found that various strains of L. casei grew in a chemically defined medium containing sulfide as the sole sulfur source, indicating the presence of a serine O-acetyltransferase. The gene lying upstream of cysK is predicted to encode a homoserine trans-succinylase (metA). To study the function of this gene, it was cloned from L. casei FAM18110. The purified, recombinant protein did not acylate L-homoserine in vitro. Instead, it catalyzed the formation of O-acetyl serine from L-serine and acetyl-CoA. Furthermore, the plasmid expressing the L. casei gene complemented an Escherichia coli cysE mutant strain but not an E. coli metA mutant. This clearly demonstrated that the gene annotated as metA in fact encodes the SAT function and should be annotated as cysE. PMID:26790714

  9. Chemoproteomic Profiling of Lysine Acetyltransferases Highlights an Expanded Landscape of Catalytic Acetylation

    PubMed Central

    2015-01-01

    Lysine acetyltransferases (KATs) play a critical role in the regulation of gene expression, metabolism, and other key cellular functions. One shortcoming of traditional KAT assays is their inability to study KAT activity in complex settings, a limitation that hinders efforts at KAT discovery, characterization, and inhibitor development. To address this challenge, here we describe a suite of cofactor-based affinity probes capable of profiling KAT activity in biological contexts. Conversion of KAT bisubstrate inhibitors to clickable photoaffinity probes enables the selective covalent labeling of three phylogenetically distinct families of KAT enzymes. Cofactor-based affinity probes report on KAT activity in cell lysates, where KATs exist as multiprotein complexes. Chemical affinity purification and unbiased LC–MS/MS profiling highlights an expanded landscape of orphan lysine acetyltransferases present in the human genome and provides insight into the global selectivity and sensitivity of CoA-based proteomic probes that will guide future applications. Chemoproteomic profiling provides a powerful method to study the molecular interactions of KATs in native contexts and will aid investigations into the role of KATs in cell state and disease. PMID:24836640

  10. A three-generation family with terminal microdeletion involving 5p15.33-32 due to a whole-arm 5;15 chromosomal translocation with a steady phenotype of atypical cri du chat syndrome.

    PubMed

    Elmakky, Amira; Carli, Diana; Lugli, Licia; Torelli, Paola; Guidi, Battista; Falcinelli, Cristina; Fini, Sergio; Ferrari, Fabrizio; Percesepe, Antonio

    2014-03-01

    Cri du chat syndrome is characterized by cat-like cry, facial dysmorphisms, microcephaly, speech delay, intellectual disability and slow growth rate, which are present with variable frequency. The typical cri du chat syndrome, due to 5p15.2 deletion, includes severe intellectual disability, facial dysmorphisms, neonatal hypotonia and pre- and post-natal growth retardation, whereas more distal deletions in 5p15.3 lead to cat-like cry and speech delay and produce the clinical picture of the atypical cri du chat syndrome, with minimal or absent intellectual impairment. In this article we report a three-generation family with an unbalanced whole arm translocation between chromosome 5 and 15 and a microdeletion of 5.5 Mb involving 5p15.33-32. By reporting the smallest terminal deletion of 5p15.3 described so far and by reviewing the literature we discuss the genotype/phenotype correlations of the distal region of the cri du chat syndrome. The previously described critical region for the speech delay may be narrowed down and microcephaly, growth retardation and dysmorphic facial features can be included in the phenotypic expression of the atypical cri du chat syndrome due to 5p15.3 deletions. PMID:24556499

  11. Chat Widgets on the Library Website: Help at the Point of Need

    ERIC Educational Resources Information Center

    Meier, John J.

    2008-01-01

    This article describes the use of chat widgets on library websites and how it affects daily work and organizational culture. The use of chat widgets can be as simple or confusing as the website itself, but it helps to make choices that fit the web design and the organizational culture. Too often change is driven from outside, which can make…

  12. Tutorial Chat: A Case Study of Synchronous Communication in a Learning Environment

    ERIC Educational Resources Information Center

    Rutter, Malcolm

    2006-01-01

    This case study describes the use of a web-based synchronous chat application, run during computing tutorials. The chat room was moderated by a paid demonstrator, who assisted and encouraged students whenever possible. Most of the discussion was banter, which acted as a lubricant for relevant factual communication. Students were permitted a degree…

  13. Synchronous CMC and Pragmatic Development: Effects of Oral and Written Chat

    ERIC Educational Resources Information Center

    Sykes, Julie M.

    2005-01-01

    This study systematically examines the strength of the connection between synchronous CMC and pragmatic instruction by measuring the effects of three types of synchronous group discussion (written chat [WC], oral chat [OC], and traditional face-to-face [FF] discussion) on the acquisition of the speech act (refusals of an invitation) in the target…

  14. Evaluating a Chat Reference Service at the University of South Alabama's Baugh Biomedical Library

    ERIC Educational Resources Information Center

    Clanton, Clista C.; Staggs, Geneva B.; Williams, Thomas L.

    2006-01-01

    The University of South Alabama's Baugh Biomedical Library recently initiated a chat reference service targeted at distance education students in the biomedical sciences. After one year of service, the library conducted an evaluation of the chat reference to assess the success of this mode of reference service. Both traditional reference and…

  15. Chat Reference Training after One Decade: The Results of a National Survey of Academic Libraries

    ERIC Educational Resources Information Center

    Devine, Christopher; Paladino, Emily Bounds; Davis, John A.

    2011-01-01

    The first comprehensive national survey of all academic libraries in the United States which were conducting chat reference service was carried out to determine: what practices were being used to prepare personnel for chat reference service, what competencies were being taught, how and why training practices may have changed over time, and what…

  16. R-U-Typing-2-Me? Evolving a Chat Tool to Increase Understanding in Learning Activities

    ERIC Educational Resources Information Center

    Fuks, Hugo; Pimentel, Mariano; Lucena, Carlos Jose Pereira de

    2006-01-01

    Very often, when using a chat tool where more than one participant is talking simultaneously, it is difficult to follow the conversation, read all the different messages and work out who is talking to whom about what. This problem has been dubbed "Chat Confusion." This article investigates this problem in debate sessions in an online university…

  17. Visualization of Expert Chat Development in a World of Warcraft Player Group

    ERIC Educational Resources Information Center

    Chen, Mark

    2009-01-01

    This article describes expertise development in a player group in the massively multiplayer online game World of Warcraft using visualization of chat log data. Charts were created to get a general sense of chat trends in a specific player group engaged in "high-end raiding", a 40-person collaborative activity. These charts helped identify patterns…

  18. Synchronous Discussion in Online Courses: A Pedagogical Strategy for Taming the Chat Beast

    ERIC Educational Resources Information Center

    Smith, Craig W.

    2006-01-01

    Many online classes use synchronous communication--chat--as a way to conduct class discussion. However, chat can quickly disintegrate into nonproductive chaos if allowed to flow unchecked. The tools provided by course management systems such as Blackboard provide one solution to this problem by allowing instructors to grant or deny access to…

  19. Potential of Text-Based Internet Chats for Improving Oral Fluency in a Second Language

    ERIC Educational Resources Information Center

    Blake, Christopher

    2009-01-01

    Although a number of studies have reported on the positive effects of Internet chats in the second language classroom, to the best of my knowledge no studies to date have examined the effect of text-based chats on oral fluency development. This exploratory study addressed the above question by examining the oral fluency development of 34 English…

  20. Conversations--and Negotiated Interaction--in Text and Voice Chat Rooms

    ERIC Educational Resources Information Center

    Jepson, Kevin

    2005-01-01

    Despite the expanded use of the Internet for language learning and practice, little attention if any has been given to the quality of interaction among English L2 speakers in conversational text or voice chat rooms. This study explored the patterns of repair moves in synchronous non-native speaker (NNS) text chat rooms in comparison to voice chat…

  1. A Linguistic Analysis of Chat Reference Conversations with 18-24 Year-Old College Students

    ERIC Educational Resources Information Center

    Maness, Jack M.

    2008-01-01

    Thirty-one chat reference conversations were linguistically analyzed, compared to twenty-three instant messaging (IM) conversations held between students, and further correlated to students' satisfaction with the reference interaction. Conversations between librarians and students in chat reference are more formal than those solely involving…

  2. Overlapping Chat's Accessibility Requirements between Students with and without Disabilities Due to the Mobile Limitations

    ERIC Educational Resources Information Center

    Calvo, Rocío; Iglesias, Ana; Moreno, Lourdes

    2014-01-01

    The use of Chats has been extended to mobile-learning (m-learning) environments in the last decade. Students and teachers can communicate in real time and they do not need waiting till their next tutoring date to solve their problems and doubts. However, Chats have many accessibility barriers and many students cannot use this collaborative tool.…

  3. "PolyCAFe"--Automatic Support for the Polyphonic Analysis of CSCL Chats

    ERIC Educational Resources Information Center

    Trausan-Matu, Stefan; Dascalu, Mihai; Rebedea, Traian

    2014-01-01

    Chat conversations and other types of online communication environments are widely used within CSCL educational scenarios. However, there is a lack of theoretical and methodological background for the analysis of collaboration. Manual assessing of non-moderated chat discussions is difficult and time-consuming, having as a consequence that learning…

  4. Methodological Issues in Developing a Multi-Dimensional Coding Procedure for Small-Group Chat Communication

    ERIC Educational Resources Information Center

    Strijbos, Jan-Willem; Stahl, Gerry

    2007-01-01

    In CSCL research, collaboration through chat has primarily been studied in dyadic settings. This article discusses three issues that emerged during the development of a multi-dimensional coding procedure for small-group chat communication: (a) the unit of analysis and unit fragmentation, (b) the reconstruction of the response structure and (c)…

  5. Radioenzymatic assays for aminoglycosides with kanamycin 6'- acetyltransferase

    SciTech Connect

    Weber, A.; Smith, A.L.; Opheim, K.E.

    1985-03-01

    To facilitate the rapid and accurate quantitation of parenterally administered aminoglycosides, the optimum conditions (pH, duration of incubation, and cofactor concentrations) were defined to permit radioenzymatic assays with kanamycin acetyltransferase. The accuracy in quantitating tobramycin, netilmicin, kanamycin, and amikacin at concentrations in the therapeutic range was greater than 90%, with a mean recovery of 102.8%. The mean of the interassay coefficient of variation was 7.8%. Typical standard curves at six different concentrations resulted in a correlation coefficient (r value) of greater than 0.99 for each aminoglycoside. The radioenzymatic assay correlates well with the bioassay (tobramycin and netilmicin) and radioimmunoassay (amikacin and kanamycin); the correlation coefficient is greater than 0.90 for all. The authors conclude that the radioenzymatic assay utilizing kanamycin 6'-acetyltransferase is feasible for all commercially available parenterally administered aminoglycosides.

  6. A new arylalkylamine N-acetyltransferase in silkworm (Bombyx mori) affects integument pigmentation.

    PubMed

    Long, Yaohang; Li, Jiaorong; Zhao, Tianfu; Li, Guannan; Zhu, Yong

    2015-04-01

    Dopamine is a precursor for melanin synthesis. Arylalkylamine N-acetyltransferase (AANAT) is involved in the melatonin formation in insects because it could catalyze the transformation from dopamine to dopamine-N-acetyldopamine. In this study, we identified a new AANAT gene in the silkworm (Bombyx mori) and assessed its role in the silkworm. The cDNA of this gene encodes 233 amino acids that shares 57 % amino acid identity with the Bm-iAANAT protein. We thus refer to this gene as Bm-iAANAT2. To investigate the role of Bm-iAANAT2, we constructed a transgenic interference system using a 3xp3 promoter to suppress the expression of Bm-iAANAT2 in the silkworm. We observed that melanin deposition occurs in the head and integument in transgenic lines. To verify the melanism pattern, dopamine content and the enzyme activity of AANAT were determined by high-performance liquid chromatography (HPLC). We found that an increase in dopamine levels affects melanism patterns on the heads of transgenic B. mori. A reduction in the enzyme activity of AANAT leads to changes in dopamine levels. We analyzed the expression of the Bm-iAANAT2 genes by qPCR and found that the expression of Bm-iAANAT2 gene is significantly lower in transgenic lines. Our results lead us to conclude that Bm-iAANAT2 is a new arylalkylamine N-acetyltransferase gene in the silkworm and is involved in the metabolism of the dopamine to avoid the generation of melanin. PMID:25712907

  7. The transcriptional coactivator and acetyltransferase p300 in fibroblast biology and fibrosis.

    PubMed

    Ghosh, Asish K; Varga, John

    2007-12-01

    The transcriptional coactivator p300 is a ubiquitous nuclear phosphoprotein and transcriptional cofactor with intrinsic acetyltransferase activity. p300 controls the expression of numerous genes in cell-type and signal-specific manner, and plays a pivotal role in cellular proliferation, apoptosis, and embryogenesis. By catalyzing acetylation of histones and transcription factors, p300 plays a significant role in epigenetic regulation. Recent evidence suggests that abnormal p300 function is associated with deregulated target gene expression, and is implicated in inflammation, cancer, cardiac hypertrophy, and genetic disorders such as the Rubinstein-Taybi syndrome. The activity of p300 is regulated at multiple levels, including developmental stage-specific expression, post-translational modifications, subcellular localization, and cell-type and gene-specific interactions with transcription factors. Although p300 has been investigated extensively in epithelial and hematopoietic cells, its role in fibroblast biology and tissue repair has received little attention to date. Recent studies implicate p300 in the regulation of collagen synthesis by transforming growth factor-beta (TGF-beta). Both the acetyltransferase activity of p300 and its inducible interaction with Smad3 are essential for mediating TGF-beta-induced stimulation of collagen synthesis. As a signal integrator whose availability for intracellular interactions with transcription factors is strictly limiting, p300 mediates the antagonistic regulation of TGF-beta-induced collagen synthesis by IFN-gamma and TNF-alpha via intracellular competition for limiting amount of p300. Significantly, p300 is itself a direct transcriptional target of TGF-beta in normal fibroblasts, and its levels are significantly elevated in fibrotic lesions as well as in experimental models of fibrosis. The emerging appreciation of the importance of p300 in extracellular matrix (ECM) remodeling and fibrosis and novel insights concerning

  8. Histone acetyltransferase HAT4 modulates navigation across G2/M and re-entry into G1 in Leishmania donovani

    PubMed Central

    Yadav, Aarti; Chandra, Udita; Saha, Swati

    2016-01-01

    Histone acetyltransferases impact multiple processes. This study investigates the role of histone acetyltransferase HAT4 in Leishmania donovani. Though HAT4 was dispensable for survival, its elimination decreased cell viability and caused cell cycle defects, with HAT4-nulls experiencing an unusually long G2/M. Survival of HAT4-nulls in macrophages was also substantially compromised. DNA microarray analysis revealed that HAT4 modestly regulated the expression of only a select number of genes, thus not being a major modulator of global gene expression. Significantly, cdc20 was among the downregulated genes. To ascertain if decreased expression of cdc20 was responsible for HAT4-null growth and cell cycle defects we expressed LdCdc20 ectopically in HAT4-nulls. We found this to alleviate the aberrant growth and cell cycle progression patterns displayed by HAT4-nulls, with cells navigating G2/M phase and re-entering G1 phase smoothly. HAT4-nulls expressing LdCdc20 ectopically showed survival rates comparable to wild type within macrophages, suggesting that G2/M defects were responsible for poor survival of HAT4-nulls within host cells also. These are the first data analyzing the in vivo functional role of HAT4 in any trypanosomatid. Our results directly demonstrate for the first time a role for Cdc20 in regulating trypanosomatid G2/M events, opening avenues for further research in this area. PMID:27272906

  9. Histone acetyltransferase HAT4 modulates navigation across G2/M and re-entry into G1 in Leishmania donovani.

    PubMed

    Yadav, Aarti; Chandra, Udita; Saha, Swati

    2016-01-01

    Histone acetyltransferases impact multiple processes. This study investigates the role of histone acetyltransferase HAT4 in Leishmania donovani. Though HAT4 was dispensable for survival, its elimination decreased cell viability and caused cell cycle defects, with HAT4-nulls experiencing an unusually long G2/M. Survival of HAT4-nulls in macrophages was also substantially compromised. DNA microarray analysis revealed that HAT4 modestly regulated the expression of only a select number of genes, thus not being a major modulator of global gene expression. Significantly, cdc20 was among the downregulated genes. To ascertain if decreased expression of cdc20 was responsible for HAT4-null growth and cell cycle defects we expressed LdCdc20 ectopically in HAT4-nulls. We found this to alleviate the aberrant growth and cell cycle progression patterns displayed by HAT4-nulls, with cells navigating G2/M phase and re-entering G1 phase smoothly. HAT4-nulls expressing LdCdc20 ectopically showed survival rates comparable to wild type within macrophages, suggesting that G2/M defects were responsible for poor survival of HAT4-nulls within host cells also. These are the first data analyzing the in vivo functional role of HAT4 in any trypanosomatid. Our results directly demonstrate for the first time a role for Cdc20 in regulating trypanosomatid G2/M events, opening avenues for further research in this area. PMID:27272906

  10. Chagas’ disease parasite-derived neurotrophic factor activates cholinergic gene expression in neuronal PC12 cells

    PubMed Central

    Akpan, Nsikan; Caradonna, Kacey; Chuenkova, Marina V.; PereiraPerrin, Mercio

    2008-01-01

    A parasite-derived neurotrophic factor (PDNF) produced by the Chagas’ disease parasite Trypanosoma cruzi binds nerve growth factor (NGF) receptor TrkA, increasing receptor autophosphorylation, activating phosphatidylinositol 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK/Erk) pathways, and transcription factor CREB. The end-result is enhanced survival and neuritogenesis of various types of neurons. PDNF also enhances the expression and activity of tyrosine hydroxylase, a rate limiting enzyme in the synthesis of dopamine and other catecholamine neurotransmitters. It remains unknown, however, if PDNF alters expression and metabolism of acetylcholine (ACh), a neurotransmitter thought to play a role in Chagas’ disease progression. Here we demonstrate that PDNF stimulates mRNA and protein expression of choline acetyltransferase (ChAT) and vesicular acetylcholine transporter (VAChT), which are critical for synthesis and storage of ACh. Stimulation requires functional TrkA because it did not occur in cell mutants that lack the receptor and in TrkA-expressing wild-type cells treated with K252a, an inhibitor of TrkA kinase activity. It also requires TrkA-dependent PI3K and MAPK/Erk signaling pathways because PDNF stimulation of cholinergic transcripts is abolished by specific pharmacological inhibitors. Furthermore, the cholinergic actions of PDNF were reproduced by PDNF-expressing extracellular T. cruzi trypomastigotes at the start of host cell invasion. In contrast, host cells bearing intracellular T. cruzi showed decreased, rather than increased, cholinergic gene expression. These results suggest that T. cruzi invasion of the nervous system alters cholinergic gene expression and that could play a role in neuropathology, and/or lack thereof, in Chagas’ disease patients. PMID:18502403

  11. Chagas' disease parasite-derived neurotrophic factor activates cholinergic gene expression in neuronal PC12 cells.

    PubMed

    Akpan, Nsikan; Caradonna, Kacey; Chuenkova, Marina V; PereiraPerrin, Mercio

    2008-06-27

    A parasite-derived neurotrophic factor (PDNF) produced by the Chagas' disease parasite Trypanosoma cruzi binds nerve growth factor (NGF) receptor TrkA, increasing receptor autophosphorylation, and activating phosphatidylinositol 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK/Erk) pathways, and transcription factor CREB. The end-result is enhanced survival and neuritogenesis of various types of neurons. PDNF also enhances the expression and activity of tyrosine hydroxylase, a rate limiting enzyme in the synthesis of dopamine and other catecholamine neurotransmitters. It remains unknown, however, if PDNF alters expression and metabolism of acetylcholine (ACh), a neurotransmitter thought to play a role in Chagas' disease progression. Here we demonstrate that PDNF stimulates mRNA and protein expression of choline acetyltransferase (ChAT) and vesicular acetylcholine transporter (VAChT), which are critical for synthesis and storage of ACh. Stimulation requires functional TrkA because it did not occur in cell mutants that lack the receptor and in TrkA-expressing wild-type cells treated with K252a, an inhibitor of TrkA kinase activity. It also requires TrkA-dependent PI3K and MAPK/Erk signaling pathways because PDNF stimulation of cholinergic transcripts is abolished by specific pharmacological inhibitors. Furthermore, the cholinergic actions of PDNF were reproduced by PDNF-expressing extracellular T. cruzi trypomastigotes at the start of host cell invasion. In contrast, host cells bearing intracellular T. cruzi showed decreased, rather than increased, cholinergic gene expression. These results suggest that T. cruzi invasion of the nervous system alters cholinergic gene expression and that could play a role in neuropathology, and/or lack thereof, in Chagas' disease patients. PMID:18502403

  12. Ectopic transgene expression in the retina of four transgenic mouse lines.

    PubMed

    Gábriel, Robert; Erdélyi, Ferenc; Szabó, Gábor; Lawrence, J Josh; Wilhelm, Márta

    2016-09-01

    Retinal expression of transgenes was examined in four mouse lines. Two constructs were driven by the choline acetyltransferase (ChAT) promoter: green fluorescent protein conjugated to tau protein (tau-GFP) or cytosolic yellow fluorescent protein (YFP) generated through CRE recombinase-induced expression of Rosa26 (ChAT-CRE/Rosa26YFP). Two other constructs targeted inhibitory interneurons: GABAergic horizontal and amacrine cells identified by glutamic acid decarboxylase (GAD65-GFP) or parvalbumin (PV) cells (PV-CRE/Rosa26YFP). Animals were transcardially perfused and retinal sections prepared. Antibodies against PV, calretinin (CALR), calbindin (CALB), and tyrosine hydroxylase (TH) were used to counterstain transgene-expressing cells. In PVxRosa and ChAT-tauGFP constructs, staining appeared in vertically oriented row of processes resembling Müller cells. In the ChATxRosa construct, populations of amacrine cells and neurons in the ganglion cell layer were labeled. Some cones also exhibited GFP fluorescence. CALR, PV and TH were found in none of these cells. Occasionally, we found GFP/CALR and GFP/PV double-stained cells in the ganglion cell layer (GCL). In the GAD65-GFP construct, all layers of the neuroretina were labeled, except photoreceptors. Not all horizontal cells expressed GFP. We did not find GFP/TH double-labeled cells and GFP was rarely present in CALR- and CALB-containing cells. Many PV-positive neurons were also labeled for GFP, including small diameter amacrines. In the GCL, single labeling for GFP and PV was ascertained, as well as several CALR/PV double-stained neurons. In the GCL, cells triple labeled with GFP/CALR/CALB were sparse. In conclusion, only one of the four transgenic constructs exhibited an expression pattern consistent with endogenous retinal protein expression, while the others strongly suggested ectopic gene expression. PMID:26563404

  13. Paramecium bursaria Chlorella Virus 1 Encodes a Polyamine Acetyltransferase*

    PubMed Central

    Charlop-Powers, Zachary; Jakoncic, Jean; Gurnon, James R.; Van Etten, James L.; Zhou, Ming-Ming

    2012-01-01

    Paramecium bursaria chlorella virus 1 (PBCV-1), a large DNA virus that infects green algae, encodes a histone H3 lysine 27-specific methyltransferase that functions in global transcriptional silencing of the host. PBCV-1 has another gene a654l that encodes a protein with sequence similarity to the GCN5 family histone acetyltransferases. In this study, we report a 1.5 Å crystal structure of PBCV-1 A654L in a complex with coenzyme A. The structure reveals a unique feature of A654L that precludes its acetylation of histone peptide substrates. We demonstrate that A654L, hence named viral polyamine acetyltransferase (vPAT), acetylates polyamines such as putrescine, spermidine, cadaverine, and homospermidine present in both PBCV-1 and its host through a reaction dependent upon a conserved glutamate 27. Our study suggests that as the first virally encoded polyamine acetyltransferase, vPAT plays a possible key role in the regulation of polyamine catabolism in the host during viral replication. PMID:22277659

  14. Characterization of the mississippian chat in South-central Kansas

    USGS Publications Warehouse

    Watney, W.L.; Guy, W.J.; Byrnes, A.P.

    2001-01-01

    To understand production from low resistivity-high porosity Mississippian chat reservoirs in south-central Kansas it is necessary to understand the nature of deposition and diagenesis, how tectonics is a factor, the lithofacies controls on petrophysical properties, and log response to these properties. The initial mudstones to sponge-spicule wacke-packstones were deposited in transgressive-regressive (T-R) cycles on a shelf to shelf margin setting, resulting in a series of shallowing-upward cycles. Sponge-spicule content appears to increase upward with increasing cycle thickness. After early silicification, inter- and post-Mississippian subaerial exposure resulted in further diagenesis, including sponge-spicule dissolution, vuggy porosity development in moldic-rich rocks, and autobrecciation. Meteoric water infiltration is limited in depth below the exposure surface and in distance downdip into unaltered, cherty Cowley Formation facies. Areas of thicker preserved chat and increased diagenesis can be correlated with structural lineaments and, in some areas, with recurrent basement block movement. Combination of folding or block fault movement prior to or during development of the basal Pennsylvanian unconformity, sponge-spicule concentration, and possibly thickness of overlying bioclastic wacke-grainstones resulted in variable reservoir properties and the creation of pods of production separated by nonproductive cherty dolomite mudstones. These events also resulted in alteration of the depositional cycles to produce a series of lithofacies that exhibit unique petrophysical properties. From bottom to top in a complete cycle seven lithofacies are present: (1) argillaceous dolomite mudstone, (2) argillaceous dolomite mudstone that has chert nodules, (3) clean dolomite mudstone that has nodular chert, (4) nodular to bedded chert, (5) autoclastic chert, (6) autoclastic chert that has clay infill, and (7) bioclastic wacke-grainstone. The uppermost cycle was terminated by

  15. Primary structure of the human M2 mitochondrial autoantigen of primary biliary cirrhosis: Dihydrolipoamide acetyltransferase

    SciTech Connect

    Coppel, R.L.; McNeilage, L.J.; Surh, C.D.; Van De Water, J.; Spithill, T.W.; Whittingham, S.; Gershwin, M.E. )

    1988-10-01

    Primary biliary cirrhosis is a chronic, destructive autoimmune liver disease of humans. Patient sera are characterized by a high frequency of autoantibodies to a M{sub r} 70,000 mitochondrial antigen a component of the M2 antigen complex. The authors have identified a human cDNA clone encoding the complete amino acid sequence of this autoantigen. The predicted structure has significant similarity with the dihydrolipoamide acetyltransferase of the Escherichia coli pyruvate dehydrogenase multienzyme complex. The human sequence preserves the Glu-Thr-Asp-Lys-Ala motif of the lipoyl-binding site and has two potential binding sites. Expressed fragments of the cDNA react strongly with sera from patients with primary biliary cirrhosis but not with sera from patients with autoimmune chronic active hepatitis or sera from healthy subjects.

  16. Differential co-localization with choline acetyltransferase in nervus terminalis suggests functional differences for GnRH isoforms in bonnethead sharks (Sphyrna tiburo).

    PubMed

    Moeller, John F; Meredith, Michael

    2010-12-17

    The nervus terminalis (NT) is a vertebrate cranial nerve whose function in adults is unknown. In bonnethead sharks, the nerve is anatomically independent of the olfactory system, with two major cell populations within one or more ganglia along its exposed length. Most cells are immunoreactive for either gonadotropin-releasing hormone (GnRH) or RF-amide-like peptides. To define further the cell populations and connectivity, we used double-label immunocytochemistry with antisera to different isoforms of GnRH and to choline acetyltransferase (ChAT). The labeling patterns of two GnRH antisera revealed different populations of GnRH-immunoreactive (ir) cell profiles in the NT ganglion. One antiserum labeled a large group of cells and fibers, which likely contain mammalian GnRH (GnRH-I) as described in previous studies and which were ChAT immunoreactive. The other antiserum labeled large club-like structures, which were anuclear, and a sparse number of fibers, but with no clear labeling of cell bodies in the ganglion. These club structures were choline acetyltrasferase (ChAT)-negative, and preabsorption control tests suggest they may contain chicken-GnRH-II (GnRH-II) or dogfish GnRH. The second major NT ganglion cell-type was immunoreactive for RF-amides, which regulate GnRH release in other vertebrates, and may provide an intraganglionic influence on GnRH release. The immunocytochemical and anatomical differences between the two GnRH-immunoreactive profile types indicate possible functional differences for these isoforms in the NT. The club-like structures may be sites of GnRH release into the general circulation since these structures were observed near blood vessels and resembled structures seen in the median eminence of rats. PMID:20950589

  17. A distinct DGAT with sn-3 acetyltransferase activity that synthesizes unusual, reduced-viscosity oils in Euonymus and transgenic seeds

    PubMed Central

    Durrett, Timothy P.; McClosky, Daniel D.; Tumaney, Ajay W.; Elzinga, Dezi A.; Ohlrogge, John; Pollard, Mike

    2010-01-01

    Endosperm and embryo tissues from the seeds of Euonymus alatus (Burning Bush) accumulate high levels of 3-acetyl-1,2-diacyl-sn-glycerols (acTAGs) as their major storage lipids. In contrast, the aril tissue surrounding the seed produces long-chain triacylglycerols (lcTAGs) typical of most other organisms. The presence of the sn-3 acetyl group imparts acTAGs with different physical and chemical properties, such as a 30% reduction in viscosity, compared to lcTAGs. Comparative transcriptome analysis of developing endosperm and aril tissues using pyrosequencing technology was performed to isolate the enzyme necessary for the synthesis of acTAGs. An uncharacterized membrane-bound O-acyltransferase (MBOAT) family member was the most abundant acyltransferase in the endosperm but was absent from the aril. Expression of this MBOAT in yeast resulted in the accumulation of acTAGs but not lcTAG; hence, the enzyme was named EaDAcT (Euonymus alatus diacylglycerol acetyltransferase). Yeast microsomes expressing EaDAcT possessed acetyl-CoA diacylglycerol acetyltransferase activity but lacked long-chain acyl-CoA diacylglycerol acyltransferase activity. Expression of EaDAcT under the control of a strong, seed-specific promoter in Arabidopsis resulted in the accumulation of acTAGs, up to 40 mol % of total TAG in the seed oil. These results demonstrate the utility of deep transcriptional profiling with multiple tissues as a gene discovery strategy for low-abundance proteins. They also show that EaDAcT is the acetyltransferase necessary and sufficient for the production of acTAGs in Euonymus seeds, and that this activity can be introduced into the seeds of other plants, allowing the evaluation of these unusual TAGs for biofuel and other applications. PMID:20439724

  18. Function and subcellular localization of Gcn5, a histone acetyltransferase in Candida albicans.

    PubMed

    Chang, Peng; Fan, Xueyi; Chen, Jiangye

    2015-08-01

    Candida albicans is an opportunistic fungal pathogen commonly found in humans. It has the ability to switch reversibly between three growth forms: budding yeast, pseudohypha, and hypha. The transition between yeast and hyphal growth forms is critical for the pathogenesis of C. albicans. During the yeast-to-hypha morphologic transition, gene expression is regulated by transcriptional regulators including histone modifying complexes and chromatin remodeling complexes. We previously reported that Esa1, a catalytic subunit in the histone acetyltransferase complex NuA4, is essential for the hyphal development of C. albicans. In this study, we analyzed the functional roles of Gcn5, a catalytic subunit in the histone acetyltransferase complex SAGA, in C. albicans. Gcn5 is required for the invasive and filamentous growth of C. albicans. Deletion of GCN5 impaired hyphal elongation in sensing serum and attenuated the virulence of C. albicans in a mouse systemic infection model. The C. albicans gcn5/gcn5 mutant cells also exhibited sensitivity to cell wall stress. Functional analysis showed that the HAT domain and Bromodomain in Gcn5 play distinct roles in morphogenesis and cell wall stress response of C. albicans. Our results show that the conserved residue Glu188 is crucial for the Gcn5 HAT activity and for Gcn5 function during filamentous growth. In addition, the subcellular distribution of ectopically expressed GFP-Gcn5 correlates with the different growth states of C. albicans. In stationary phase, Gcn5 accumulated in the nucleus, while during vegetative growth it localized in the cytoplasm in a morpha-independent manner. Our results suggest that the nuclear localization of Gcn5 depends on the existence of its N-terminal NLS and HAT domains. PMID:25656079

  19. A systematic review of the oral and craniofacial manifestations of cri du chat syndrome.

    PubMed

    Corcuera-Flores, José-Ramón; Casttellanos-Cosano, Lizett; Torres-Lagares, Daniel; Serrera-Figallo, María Ángeles; Rodríguez-Caballero, Ángela; Machuca-Portillo, Guillermo

    2016-07-01

    Cri du chat syndrome is an autosomal disorder. Because it affects few people in the population it is considered a rare disease, yet it is one of the most common autosomal chromosomal syndromes in humans. It entails pathognomonic alterations that affect the craniofacial and oral anatomy of patients. The aim of this study is to review these craniofacial and oral abnormalities in patients with Cri du chat syndrome. The PubMed Medline database was searched using two different strategies. First, we used "Dentistry" and "Cri du chat" as keywords; second, we used "Cri du chat" and "craniofacial." Seven articles in which the main orofacial and cranio-skeletal characteristics of patients with Cri du chat syndrome were described were selected according to the inclusion and exclusion criteria. Cri du Chat syndrome entails pathognomonic characteristics in the craniofacial area (epicanthus, short philtrum, and wide nasal bridge), the oral area (mandibular retrognathism and anterior open bite) and the cranial region (alterations at the cranial base angle and a small upper airway). However, more studies on larger samples are needed to specify the orofacial and craniofacial characteristics of patients with Cri du chat syndrome more accurately. Clin. Anat. 29:555-560, 2016. © 2015 Wiley Periodicals, Inc. PMID:26457586

  20. M-CHAT Mexican Version Validity and Reliability and Some Cultural Considerations

    PubMed Central

    Albores-Gallo, Lilia; Roldán-Ceballos, Ofelia; Villarreal-Valdes, Gabriela; Betanzos-Cruz, Blanca Xochitl; Santos-Sánchez, Claudia; Martínez-Jaime, Maria Magdalena; Lemus-Espinosa, Isaac; Hilton, Claudia List

    2012-01-01

    The Modified Checklist for Autism in Toddlers (M-CHAT) questionnaire is a brief measure available in Spanish which needs to be validated for the Mexican population. Parents of children from (1) community with typical development (TD) and (2) psychiatric outpatient unit completed the CBCL/1.5–5 and the Mexican/MM-CHAT-version. The study sample consisted of 456 children (age M = 4.46, SD = 1.12), 74.34% TD children and 26.65% with Autism Spectrum Disorders (ASD). The MM-CHAT mean score for failed key items was higher for the ASD group compared with the TD group. Internal consistency for the Mexican/M-CHAT version was .76 for total score and .70 for the 6 critical items. Correlations between the MM-CHAT and the CBCL/1.5: PDD and Withdrawn subscales and with ADI-R dimensions: B non verbal) and A were high, and were moderate with ADI-R dimensions B1 (verbal) and C The failure rate of the MM-CHAT between the groups did not reproduce all the critical items found in other studies. Although the instrument has good psychometric properties and can be used for screening purposes in primary settings or busy specialized psychiatric clinics, these results support evidence for cultural differences in item responses, making it difficult to compare M-CHAT results internationally. PMID:22811934

  1. Emotion Chat: A Web Chatroom with Emotion Regulation for E-Learners

    NASA Astrophysics Data System (ADS)

    Zheng, Deli; Tian, Feng; Liu, Jun; Zheng, Qinghua; Qin, Jiwei

    In order to compensate for lack of emotion communication between teachers and students in e-learning systems, we have designed and implemented the EmotionChat -- a web chatroom with emotion regulation. EmotionChat perceives e-learners' emotional states based on interactive text. And it recommends resources such as music, cartoons, and mottos to an e-learner when it detects negative emotional states. Meanwhile, it recommends emotion regulation cases to the e-learner's listeners and teachers. The result of our initial experiment shows that EmotionChat can recommend valuable emotion regulation policies for e-learners.

  2. 2-Amino-3,8-dimethylimidazo-[4,5-f]quinoxaline-induced DNA adduct formation and mutagenesis in DNA repair-deficient Chinese hamster ovary cells expressing human cytochrome P4501A1 and rapid or slow acetylator N-acetyltransferase 2.

    PubMed

    Bendaly, Jean; Zhao, Shuang; Neale, Jason R; Metry, Kristin J; Doll, Mark A; States, J Christopher; Pierce, William M; Hein, David W

    2007-07-01

    2-Amino-3,8-dimethylimidazo-[4,5-f]quinoxaline (MeIQx) is one of the most potent and abundant mutagens in the western diet. Bioactivation includes N-hydroxylation catalyzed by cytochrome P450s followed by O-acetylation catalyzed by N-acetyltransferase 2 (NAT2). In humans, NAT2*4 allele is associated with rapid acetylator phenotype, whereas NAT2*5B allele is associated with slow acetylator phenotype. We hypothesized that rapid acetylator phenotype predisposes humans to DNA damage and mutagenesis from MeIQx. Nucleotide excision repair-deficient Chinese hamster ovary cells were constructed by stable transfection of human cytochrome P4501A1 (CYP1A1) and a single copy of either NAT2*4 (rapid acetylator) or NAT2*5B (slow acetylator) alleles. CYP1A1 and NAT2 catalytic activities were undetectable in untransfected Chinese hamster ovary cell lines. CYP1A1 activity did not differ significantly (P > 0.05) among the CYP1A1-transfected cell lines. Cells transfected with NAT2*4 had 20-fold significantly higher levels of sulfamethazine N-acetyltransferase (P = 0.0001) and 6-fold higher levels of N-hydroxy-MeIQx O-acetyltransferase (P = 0.0093) catalytic activity than cells transfected with NAT2*5B. Only cells transfected with both CYP1A1 and NAT2*4 showed concentration-dependent cytotoxicity and hypoxanthine phosphoribosyl transferase mutagenesis following MeIQx treatment. Deoxyguanosine-C8-MeIQx was the primary DNA adduct formed and levels were dose dependent in each cell line and in the following order: untransfected < transfected with CYP1A1 < transfected with CYP1A1 and NAT2*5B < transfected with CYP1A1 and NAT2*4. MeIQx DNA adduct levels were significantly higher (P < 0.001) in CYP1A1/NAT2*4 than CYP1A1/NAT2*5B cells at all concentrations of MeIQx tested. MeIQx-induced DNA adduct levels correlated very highly (r2 = 0.88) with MeIQx-induced mutants. These results strongly support extrahepatic activation of MeIQx by CYP1A1 and a robust effect of human NAT2 genetic polymorphism

  3. Hello Harlie: Enabling Speech Monitoring Through Chat-Bot Conversations.

    PubMed

    Ireland, David; Atay, Christina; Liddle, Jacki; Bradford, Dana; Lee, Helen; Rushin, Olivia; Mullins, Thomas; Angus, Dan; Wiles, Janet; McBride, Simon; Vogel, Adam

    2016-01-01

    People with neurological conditions such as Parkinson's disease and dementia are known to have difficulties in language and communication. This paper presents initial testing of an artificial conversational agent, called Harlie. Harlie runs on a smartphone and is able to converse with the user on a variety of topics. A description of the application and a sample dialog are provided to illustrate the various roles chat-bots can play in the management of neurological conditions. Harlie can be used for measuring voice and communication outcomes during the daily life of the user, and for gaining information about challenges encountered. Moreover, it is anticipated that she may also have an educational and support role. PMID:27440289

  4. Dan Goldin chats with First Lady Hillary Clinton

    NASA Technical Reports Server (NTRS)

    1999-01-01

    At the Apollo/Saturn V Center, NASA Administrator Daniel Goldin (right) chats with First Lady Hillary Rodham Clinton and others while waiting for the launch of STS-93. Much attention has been generated over STS-93 due to Commander Eileen M. Collins, the first woman to serve as commander of a Shuttle mission. The primary payload of the five-day mission is the Chandra X-ray Observatory, which will allow scientists from around the world to study some of the most distant, powerful and dynamic objects in the universe. The new telescope is 20 to 50 times more sensitive than any previous X-ray telescope and is expected to unlock the secrets of supernovae, quasars and black holes. Liftoff of Space Shuttle Columbia is scheduled for 12:36 a.m. EDT July 20.

  5. Cholinergic chemosensory cells of the thymic medulla express the bitter receptor Tas2r131.

    PubMed

    Soultanova, Aichurek; Voigt, Anja; Chubanov, Vladimir; Gudermann, Thomas; Meyerhof, Wolfgang; Boehm, Ulrich; Kummer, Wolfgang

    2015-11-01

    The thymus is the site of T cell maturation which includes positive selection in the cortex and negative selection in the medulla. Acetylcholine is locally produced in the thymus and cholinergic signaling influences the T cell development. We recently described a distinct subset of medullary epithelial cells in the murine thymus which express the acetylcholine-synthesizing enzyme choline acetyltransferase (ChAT) and components of the canonical taste transduction cascade, i.e. transient receptor potential melastatin-like subtype 5 channel (TRPM5), phospholipase Cβ(2), and Gα-gustducin. Such a chemical phenotype is characteristic for chemosensory cells of mucosal surfaces which utilize bitter receptors for detection of potentially hazardous compounds and cholinergic signaling to initiate avoidance reflexes. We here demonstrate mRNA expression of bitter receptors Tas2r105, Tas2r108, and Tas2r131 in the murine thymus. Using a Tas2r131-tauGFP reporter mouse we localized the expression of this receptor to cholinergic cells expressing the downstream elements of the taste transduction pathway. These cells are distinct from the medullary thymic epithelial cells which promiscuously express tissue-restricted self-antigens during the process of negative selection, since double-labeling immunofluorescence showed no colocalization of autoimmune regulator (AIRE), the key mediator of negative selection, and TRPM5. These data demonstrate the presence of bitter taste-sensing signaling in cholinergic epithelial cells in the thymic medulla and opens a discussion as to what is the physiological role of this pathway. PMID:26102274

  6. Sulphoacetaldehyde acetyltransferase yields acetyl phosphate: purification from Alcaligenes defragrans and gene clusters in taurine degradation.

    PubMed

    Ruff, Jürgen; Denger, Karin; Cook, Alasdair M

    2003-01-15

    The facultatively anaerobic bacterium Alcaligenes defragrans NKNTAU was found to oxidize taurine (2-aminoethanesulphonate) with nitrate as the terminal electron acceptor. Taurine was transaminated to 2-sulphoacetaldehyde. This was not converted into sulphite and acetate by a "sulphoacetaldehyde sulpho-lyase" (EC 4.4.1.12), but into sulphite and acetyl phosphate, which was identified by three methods. The enzyme, which required the addition of phosphate, thiamin diphosphate and Mg(2+) ions for activity, was renamed sulphoacetaldehyde acetyltransferase (Xsc; EC 2.3.1.-). Inducible Xsc was expressed at high levels, and a three-step 11-fold purification yielded an essentially homogeneous soluble protein, which was a homotetramer in its native form; the molecular mass of the subunit was found to be between about 63 kDa (SDS/PAGE) and 65.3 kDa (matrix-assisted laser-desorption ionization-time-of-flight MS). The N-terminal and two internal amino acid sequences were determined, and PCR primers were generated. The xsc gene was amplified and sequenced; the derived molecular mass of the processed protein was 65.0 kDa. The downstream gene presumably encoded the inducible phosphate acetyltransferase (Pta) found in crude extracts. The desulphonative enzymes ("EC 4.4.1.12") from Achromobacter xylosoxidans NCIMB 10751 and Desulfonispora thiosulfatigenes GKNTAU were shown to be Xscs. We detected at least three subclasses of xsc in Proteobacteria and in Gram-positive bacteria, and they comprised a distinct group within the acetohydroxyacid synthase supergene family. Genome sequencing data revealed xsc genes in Burkholderia fungorum (80% sequence identity) and Sinorhizobium meliloti (61%) with closely linked pta genes. Different patterns of regulation for the transport and dissimilation of taurine were hypothesized for S. meliloti and B. fungorum. PMID:12358600

  7. Sulphoacetaldehyde acetyltransferase yields acetyl phosphate: purification from Alcaligenes defragrans and gene clusters in taurine degradation.

    PubMed Central

    Ruff, Jürgen; Denger, Karin; Cook, Alasdair M

    2003-01-01

    The facultatively anaerobic bacterium Alcaligenes defragrans NKNTAU was found to oxidize taurine (2-aminoethanesulphonate) with nitrate as the terminal electron acceptor. Taurine was transaminated to 2-sulphoacetaldehyde. This was not converted into sulphite and acetate by a "sulphoacetaldehyde sulpho-lyase" (EC 4.4.1.12), but into sulphite and acetyl phosphate, which was identified by three methods. The enzyme, which required the addition of phosphate, thiamin diphosphate and Mg(2+) ions for activity, was renamed sulphoacetaldehyde acetyltransferase (Xsc; EC 2.3.1.-). Inducible Xsc was expressed at high levels, and a three-step 11-fold purification yielded an essentially homogeneous soluble protein, which was a homotetramer in its native form; the molecular mass of the subunit was found to be between about 63 kDa (SDS/PAGE) and 65.3 kDa (matrix-assisted laser-desorption ionization-time-of-flight MS). The N-terminal and two internal amino acid sequences were determined, and PCR primers were generated. The xsc gene was amplified and sequenced; the derived molecular mass of the processed protein was 65.0 kDa. The downstream gene presumably encoded the inducible phosphate acetyltransferase (Pta) found in crude extracts. The desulphonative enzymes ("EC 4.4.1.12") from Achromobacter xylosoxidans NCIMB 10751 and Desulfonispora thiosulfatigenes GKNTAU were shown to be Xscs. We detected at least three subclasses of xsc in Proteobacteria and in Gram-positive bacteria, and they comprised a distinct group within the acetohydroxyacid synthase supergene family. Genome sequencing data revealed xsc genes in Burkholderia fungorum (80% sequence identity) and Sinorhizobium meliloti (61%) with closely linked pta genes. Different patterns of regulation for the transport and dissimilation of taurine were hypothesized for S. meliloti and B. fungorum. PMID:12358600

  8. Rapid, sensitive, and inexpensive assay for chloramphenicol acetyltransferase

    SciTech Connect

    Nordeen, S.K.; Green, P.P. III; Fowlkes, D.M.

    1987-04-01

    We present a rapid, sensitive enzymatic assay for chloramphenicol acetyltransferase (CAT) that does not require chromatography, HPLC, or autoradiography. The assay is based on the use of an inexpensive substrate, tritiated acetate, instead of (/sup 14/C)chloramphenicol. The method is adapted from one originally used by de Crombrugghe et al. and by Shaw, but with simplifications appropriate for routine use. In our hands, the method is as sensitive as the customary thin-layer chromatography assay and is far more efficient for the performance of many assays, both in terms of labor and expense.

  9. 40 CFR 278.3 - Criteria for use of chat in Federally funded transportation projects.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) IN ASPHALT CONCRETE AND PORTLAND CEMENT CONCRETE IN TRANSPORTATION CONSTRUCTION PROJECTS FUNDED IN..., or in epoxy seal; or (b) The chat is used in Portland cement concrete, granular road base,...

  10. 40 CFR 278.3 - Criteria for use of chat in Federally funded transportation projects.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) IN ASPHALT CONCRETE AND PORTLAND CEMENT CONCRETE IN TRANSPORTATION CONSTRUCTION PROJECTS FUNDED IN..., or in epoxy seal; or (b) The chat is used in Portland cement concrete, granular road base,...

  11. 40 CFR 278.3 - Criteria for use of chat in Federally funded transportation projects.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) IN ASPHALT CONCRETE AND PORTLAND CEMENT CONCRETE IN TRANSPORTATION CONSTRUCTION PROJECTS FUNDED IN..., or in epoxy seal; or (b) The chat is used in Portland cement concrete, granular road base,...

  12. 40 CFR 278.3 - Criteria for use of chat in Federally funded transportation projects.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) IN ASPHALT CONCRETE AND PORTLAND CEMENT CONCRETE IN TRANSPORTATION CONSTRUCTION PROJECTS FUNDED IN..., or in epoxy seal; or (b) The chat is used in Portland cement concrete, granular road base,...

  13. 40 CFR 278.3 - Criteria for use of chat in Federally funded transportation projects.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) IN ASPHALT CONCRETE AND PORTLAND CEMENT CONCRETE IN TRANSPORTATION CONSTRUCTION PROJECTS FUNDED IN..., or in epoxy seal; or (b) The chat is used in Portland cement concrete, granular road base,...

  14. Genome-Wide Relationships between TAF1 and Histone Acetyltransferases in Saccharomyces cerevisiae†

    PubMed Central

    Durant, Melissa; Pugh, B. Franklin

    2006-01-01

    Histone acetylation regulates gene expression, yet the functional contributions of the numerous histone acetyltransferases (HATs) to gene expression and their relationships with each other remain largely unexplored. The central role of the putative HAT-containing TAF1 subunit of TFIID in gene expression raises the fundamental question as to what extent, if any, TAF1 contributes to acetylation in vivo and to what extent it is redundant with other HATs. Our findings herein do not support the basic tenet that TAF1 is a major HAT in Saccharomyces cerevisiae, nor do we find that TAF1 is functionally redundant with other HATs, including Gcn5, Elp3, Hat1, Hpa2, Sas3, and Esa1, which is in contrast to previous conclusions regarding Gcn5. Our findings do reveal that of these HATs, only Gcn5 and Esa1 contribute substantially to gene expression genome wide. Interestingly, histone acetylation at promoter regions throughout the genome does not require TAF1 or RNA polymerase II, indicating that most acetylation is likely to precede transcription and not depend upon it. TAF1 function has been linked to Bdf1, which binds TFIID and acetylated histone H4 tails, but no linkage between TAF1 and the H4 HAT Esa1 has been established. Here, we present evidence for such a linkage through Bdf1. PMID:16537921

  15. A yeast artificial chromosome contig of the critical region for cri-du-chat syndrome

    SciTech Connect

    Goodart, S.A.; Rojas, K.; Overhauser, J.

    1994-11-01

    Cri-du-chat is a chromosomal deletion syndrome characterized by partial deletion of the short arm of chromosome 5. The clinical symptoms include growth and mental retardation, microcephaly, hypertelorism, epicanthal folds, hyptonia, and a high-pitched monochromatic cry that is usually considered diagnostic for the syndrome. Recently, a correlation between clinical features and the extent of the chromosome 5 deletions has identified two regions of the short arm that appear to be critical for the abnormal development manifested in this syndrome. Loss of a small region in 5p15.2 correlates with all of the clinical features of cri-du-chat with the exception of the cat-like cry, which maps to 5p15.3. Here the authors report the construction of a YAC contig that spans the chromosomal region in 5p15.2 that plays a major role in the etiology of the cri-du-chat syndrome. YACs that span the 2-Mb cri-du-chat critical region have been identified and characterized. This YAC contig lays the groundwork for the construction of a transcriptional map of this region and the eventual identification of genes involved in the clinical features associated with the cri-du-chat syndrome. It also provides a new diagnostic tool for cri-du-chat in the shape of a YAC clone that may span the entire critical region. 24 refs., 4 figs., 2 tabs.

  16. Brain Region–Specific Alterations in the Gene Expression of Cytokines, Immune Cell Markers and Cholinergic System Components during Peripheral Endotoxin–Induced Inflammation

    PubMed Central

    Silverman, Harold A; Dancho, Meghan; Regnier-Golanov, Angelique; Nasim, Mansoor; Ochani, Mahendar; Olofsson, Peder S; Ahmed, Mohamed; Miller, Edmund J; Chavan, Sangeeta S; Golanov, Eugene; Metz, Christine N; Tracey, Kevin J; Pavlov, Valentin A

    2014-01-01

    Inflammatory conditions characterized by excessive peripheral immune responses are associated with diverse alterations in brain function, and brain-derived neural pathways regulate peripheral inflammation. Important aspects of this bidirectional peripheral immune–brain communication, including the impact of peripheral inflammation on brain region–specific cytokine responses, and brain cholinergic signaling (which plays a role in controlling peripheral cytokine levels), remain unclear. To provide insight, we studied gene expression of cytokines, immune cell markers and brain cholinergic system components in the cortex, cerebellum, brainstem, hippocampus, hypothalamus, striatum and thalamus in mice after an intraperitoneal lipopolysaccharide injection. Endotoxemia was accompanied by elevated serum levels of interleukin (IL)-1β, IL-6 and other cytokines and brain region–specific increases in Il1b (the highest increase, relative to basal level, was in cortex; the lowest increase was in cerebellum) and Il6 (highest increase in cerebellum; lowest increase in striatum) mRNA expression. Gene expression of brain Gfap (astrocyte marker) was also differentially increased. However, Iba1 (microglia marker) mRNA expression was decreased in the cortex, hippocampus and other brain regions in parallel with morphological changes, indicating microglia activation. Brain choline acetyltransferase (Chat ) mRNA expression was decreased in the striatum, acetylcholinesterase (Ache) mRNA expression was decreased in the cortex and increased in the hippocampus, and M1 muscarinic acetylcholine receptor (Chrm1) mRNA expression was decreased in the cortex and the brainstem. These results reveal a previously unrecognized regional specificity in brain immunoregulatory and cholinergic system gene expression in the context of peripheral inflammation and are of interest for designing future antiinflammatory approaches. PMID:25299421

  17. Purification, crystallization and preliminary X-ray analysis of the glucosamine-6-phosphate N-acetyltransferase from human liver

    SciTech Connect

    Wang, Juan; Zhou, Yan-Feng; Li, Lan-Fen; Liang, Yu-He Su, Xiao-Dong

    2006-11-01

    Glucosamine-6-phosphate N-acetyltransferase from human liver was expressed, purified and crystallized. Diffraction data have been collected to 2.6 Å resolution. Glucosamine-6-phosphate N-acetyltransferase from human liver, which catalyzes the transfer of an acetyl group from acetyl coenzyme A (AcCoA) to the primary amine of d-glucosamine 6-phosphate to form N-acetyl-d-glucosamine 6-phosphate, was expressed in a soluble form from Escherichia coli strain BL21 (DE3). The protein was purified to homogeneity using Ni{sup 2+}-chelating chromatography followed by size-exclusion chromatography. Crystals of the protein were obtained by the hanging-drop vapour-diffusion method and diffracted to 2.6 Å resolution. The crystals belonged to space group P4{sub 1}2{sub 1}2 or P4{sub 3}2{sub 1}2, with unit-cell parameters a = b = 50.08, c = 142.88 Å.

  18. Enzyme kinetics and inhibition of histone acetyltransferase KAT8

    PubMed Central

    Wapenaar, Hannah; van der Wouden, Petra E.; Groves, Matthew R.; Rotili, Dante; Mai, Antonello; Dekker, Frank J.

    2016-01-01

    Lysine acetyltransferase 8 (KAT8) is a histone acetyltransferase (HAT) responsible for acetylating lysine 16 on histone H4 (H4K16) and plays a role in cell cycle progression as well as acetylation of the tumor suppressor protein p53. Further studies on its biological function and drug discovery initiatives will benefit from the development of small molecule inhibitors for this enzyme. As a first step towards this aim we investigated the enzyme kinetics of this bi-substrate enzyme. The kinetic experiments indicate a ping-pong mechanism in which the enzyme binds Ac-CoA first, followed by binding of the histone substrate. This mechanism is supported by affinity measurements of both substrates using isothermal titration calorimetry (ITC). Using this information, the KAT8 inhibition of a focused compound collection around the non-selective HAT inhibitor anacardic acid has been investigated. Kinetic studies with anacardic acid were performed, based on which a model for the catalytic activity of KAT8 and the inhibitory action of AA was proposed. This enabled the calculation of the inhibition constant Ki of anacardic acid derivatives using an adaptation of the Cheng-Prusoff equation. The results described in this study give insight into the catalytic mechanism of KAT8 and present the first well-characterized small-molecule inhibitors for this HAT. PMID:26505788

  19. Molecular mechanism underlying promiscuous polyamine recognition by spermidine acetyltransferase.

    PubMed

    Sugiyama, Shigeru; Ishikawa, Sae; Tomitori, Hideyuki; Niiyama, Mayumi; Hirose, Mika; Miyazaki, Yuma; Higashi, Kyohei; Murata, Michio; Adachi, Hiroaki; Takano, Kazufumi; Murakami, Satoshi; Inoue, Tsuyoshi; Mori, Yusuke; Kashiwagi, Keiko; Igarashi, Kazuei; Matsumura, Hiroyoshi

    2016-07-01

    Spermidine acetyltransferase (SAT) from Escherichia coli, which catalyses the transfer of acetyl groups from acetyl-CoA to spermidine, is a key enzyme in controlling polyamine levels in prokaryotic cells. In this study, we determined the crystal structure of SAT in complex with spermidine (SPD) and CoA at 2.5Å resolution. SAT is a dodecamer organized as a hexamer of dimers. The secondary structural element and folding topology of the SAT dimer resemble those of spermidine/spermine N(1)-acetyltransferase (SSAT), suggesting an evolutionary link between SAT and SSAT. However, the polyamine specificity of SAT is distinct from that of SSAT and is promiscuous. The SPD molecule is also located at the inter-dimer interface. The distance between SPD and CoA molecules is 13Å. A deep, highly acidic, water-filled cavity encompasses the SPD and CoA binding sites. Structure-based mutagenesis and in-vitro assays identified SPD-bound residues, and the acidic residues lining the walls of the cavity are mostly essential for enzymatic activities. Based on mutagenesis and structural data, we propose an acetylation mechanism underlying promiscuous polyamine recognition for SAT. PMID:27163532

  20. Enzyme kinetics and inhibition of histone acetyltransferase KAT8.

    PubMed

    Wapenaar, Hannah; van der Wouden, Petra E; Groves, Matthew R; Rotili, Dante; Mai, Antonello; Dekker, Frank J

    2015-11-13

    Lysine acetyltransferase 8 (KAT8) is a histone acetyltransferase (HAT) responsible for acetylating lysine 16 on histone H4 (H4K16) and plays a role in cell cycle progression as well as acetylation of the tumor suppressor protein p53. Further studies on its biological function and drug discovery initiatives will benefit from the development of small molecule inhibitors for this enzyme. As a first step towards this aim we investigated the enzyme kinetics of this bi-substrate enzyme. The kinetic experiments indicate a ping-pong mechanism in which the enzyme binds Ac-CoA first, followed by binding of the histone substrate. This mechanism is supported by affinity measurements of both substrates using isothermal titration calorimetry (ITC). Using this information, the KAT8 inhibition of a focused compound collection around the non-selective HAT inhibitor anacardic acid has been investigated. Kinetic studies with anacardic acid were performed, based on which a model for the catalytic activity of KAT8 and the inhibitory action of anacardic acid (AA) was proposed. This enabled the calculation of the inhibition constant Ki of anacardic acid derivatives using an adaptation of the Cheng-Prusoff equation. The results described in this study give insight into the catalytic mechanism of KAT8 and present the first well-characterized small-molecule inhibitors for this HAT. PMID:26505788

  1. A Bacterial Acetyltransferase Destroys Plant Microtubule Networks and Blocks Secretion

    PubMed Central

    Lee, Amy Huei-Yi; Hurley, Brenden; Felsensteiner, Corinna; Yea, Carmen; Ckurshumova, Wenzislava; Bartetzko, Verena; Wang, Pauline W.; Quach, Van; Lewis, Jennifer D.; Liu, Yulu C.; Börnke, Frederik; Angers, Stephane; Wilde, Andrew

    2012-01-01

    The eukaryotic cytoskeleton is essential for structural support and intracellular transport, and is therefore a common target of animal pathogens. However, no phytopathogenic effector has yet been demonstrated to specifically target the plant cytoskeleton. Here we show that the Pseudomonas syringae type III secreted effector HopZ1a interacts with tubulin and polymerized microtubules. We demonstrate that HopZ1a is an acetyltransferase activated by the eukaryotic co-factor phytic acid. Activated HopZ1a acetylates itself and tubulin. The conserved autoacetylation site of the YopJ / HopZ superfamily, K289, plays a critical role in both the avirulence and virulence function of HopZ1a. Furthermore, HopZ1a requires its acetyltransferase activity to cause a dramatic decrease in Arabidopsis thaliana microtubule networks, disrupt the plant secretory pathway and suppress cell wall-mediated defense. Together, this study supports the hypothesis that HopZ1a promotes virulence through cytoskeletal and secretory disruption. PMID:22319451

  2. Using a book chat to improve attitudes and perceptions of long-term care staff about dementia.

    PubMed

    Larocque, Natasha; Schotsman, Chloe; Kaasalainen, Sharon; Crawshaw, Diane; McAiney, Carrie; Brazil, Emma

    2014-05-01

    This study sought to evaluate a book chat intervention based on Lisa Genova's novel, Still Alice, to influence long-term care (LTC) staff perceptions and attitudes when caring for individuals with dementia. A qualitative descriptive design was used. Eleven participants partook in a 2.5-hour book chat at a southern Ontario LTC facility. Following the book chat, participants answered two open-ended questions to assess how the book chat influenced their views on dementia. Thematic content analysis was used to analyze the qualitative questionnaire. Content analysis of the participants' responses revealed that the book chat positively influenced their attitudes and perceptions toward dementia, particularly by providing more insight into the individual's personal struggle with the disease. Furthermore, participants found that the book chat influenced their care practices. By creating innovative learning opportunities, attitudes and perceptions about dementia care can be transcended and greatly benefit staff, family, and residents. PMID:24443888

  3. Atomic resolution structure of human α-tubulin acetyltransferase bound to acetyl-CoA

    PubMed Central

    Taschner, Michael; Vetter, Melanie; Lorentzen, Esben

    2012-01-01

    Acetylation of lysine residues is an important posttranslational modification found in all domains of life. α-tubulin is specifically acetylated on lysine 40, a modification that serves to stabilize microtubules of axons and cilia. Whereas histone acetyltransferases have been extensively studied, there is no structural and mechanistic information available on α-tubulin acetyltransferases. Here, we present the structure of the human α-tubulin acetyltransferase catalytic domain bound to its cosubstrate acetyl-CoA at 1.05 Å resolution. Compared with other lysine acetyltransferases of known structure, α-tubulin acetyltransferase displays a relatively well-conserved cosubstrate binding pocket but is unique in its active site and putative α-tubulin binding site. Using acetylation assays with structure-guided mutants, we map residues important for acetyl-CoA binding, substrate binding, and catalysis. This analysis reveals a basic patch implicated in substrate binding and a conserved glutamine residue required for catalysis, demonstrating that the family of α-tubulin acetyltransferases uses a reaction mechanism different from other lysine acetyltransferases characterized to date. PMID:23071318

  4. Biochemical pathways that regulate acetyltransferase and deacetylase activity in mammalian cells

    PubMed Central

    Mellert, Hestia S.; McMahon, Steven B.

    2009-01-01

    Protein phosphorylation is dynamically regulated in eukaryotic cells via modulation of the enzymatic activity of kinases and phosphatases. Like phosphorylation, acetylation has emerged as a critical regulatory protein modification that is dynamically altered in response to diverse cellular cues. Moreover, acetyltransferases and deacetylases are tightly linked to cellular signaling pathways. Recent studies provide clues about the mechanisms utilized to regulate acetyltransferases and deacetylases. The therapeutic value of deacetylase inhibitors suggests that understanding acetylation pathways will directly impact our ability to rationally target these enzymes in patients. Recently discovered mechanisms which directly regulate the catalytic activity of acetyltransferases and deacetylases provide exciting new insights about these enzymes. PMID:19819149

  5. [The biological role of prokaryotic and eukaryotic N-acetyltransferase].

    PubMed

    Zabost, Anna; Zwolska, Zofia; Augustynowicz-Kopeć, Ewa

    2013-01-01

    The N-acetyltransferases (NAT; E.C.2.3.1.5) are involved in the metabolism of drugs and environmental toxins. They catalyse the acetyl transfer from acetyl coenzyme A to an aromatic amine, heterocyclic amine, or hydrazine compound. NAT homologues are present in numerous species from bacteria to human. Sequence variations in the human NAT1 and NAT2 result in the production of NAT proteins with variable enzyme activity or stability, leading to slow or rapid acetylation. Therefore, genetic polymorphisms in NAT1 and NAT2 influence drug metabolism and drug-related toxicity. Epidemiological studies suggest that the NAT1 and NAT2 acetylation polymorphisms modify the risk of developing cancers of the urinary bladder, colorectal, breast, head and neck, and lung. PMID:23420430

  6. Crystal structure of homoserine O-acetyltransferase from Leptospira interrogans

    SciTech Connect

    Wang Mingzhu; Liu Lin; Wang Yanli; Wei Zhiyi; Zhang Ping; Li Yikun; Jiang Xiaohua; Xu Hang Gong Weimin

    2007-11-30

    Homoserine O-acetyltransferase (HTA, EC 2.3.1.31) initiates methionine biosynthesis pathway by catalyzing the transfer of acetyl group from acetyl-CoA to homoserine. This study reports the crystal structure of HTA from Leptospira interrogans determined at 2.2 A resolution using selenomethionyl single-wavelength anomalous diffraction method. HTA is modular and consists of two structurally distinct domains-a core {alpha}/{beta} domain containing the catalytic site and a helical bundle called the lid domain. Overall, the structure fold belongs to {alpha}/{beta} hydrolase superfamily with the characteristic 'catalytic triad' residues in the active site. Detailed structure analysis showed that the catalytic histidine and serine are both present in two conformations, which may be involved in the catalytic mechanism for acetyl transfer.

  7. The Role of Histone Acetyltransferases in Normal and Malignant Hematopoiesis

    PubMed Central

    Sun, Xiao-Jian; Man, Na; Tan, Yurong; Nimer, Stephen D.; Wang, Lan

    2015-01-01

    Histone, and non-histone, protein acetylation plays an important role in a variety of cellular events, including the normal and abnormal development of blood cells, by changing the epigenetic status of chromatin and regulating non-histone protein function. Histone acetyltransferases (HATs), which are the enzymes responsible for histone and non-histone protein acetylation, contain p300/CBP, MYST, and GNAT family members. HATs are not only protein modifiers and epigenetic factors but also critical regulators of cell development and carcinogenesis. Here, we will review the function of HATs such as p300/CBP, Tip60, MOZ/MORF, and GCN5/PCAF in normal hematopoiesis and the pathogenesis of hematological malignancies. The inhibitors that have been developed to target HATs will also be reviewed here. Understanding the roles of HATs in normal/malignant hematopoiesis will provide the potential therapeutic targets for the hematological malignancies. PMID:26075180

  8. The Role of Histone Acetyltransferases in Normal and Malignant Hematopoiesis.

    PubMed

    Sun, Xiao-Jian; Man, Na; Tan, Yurong; Nimer, Stephen D; Wang, Lan

    2015-01-01

    Histone, and non-histone, protein acetylation plays an important role in a variety of cellular events, including the normal and abnormal development of blood cells, by changing the epigenetic status of chromatin and regulating non-histone protein function. Histone acetyltransferases (HATs), which are the enzymes responsible for histone and non-histone protein acetylation, contain p300/CBP, MYST, and GNAT family members. HATs are not only protein modifiers and epigenetic factors but also critical regulators of cell development and carcinogenesis. Here, we will review the function of HATs such as p300/CBP, Tip60, MOZ/MORF, and GCN5/PCAF in normal hematopoiesis and the pathogenesis of hematological malignancies. The inhibitors that have been developed to target HATs will also be reviewed here. Understanding the roles of HATs in normal/malignant hematopoiesis will provide the potential therapeutic targets for the hematological malignancies. PMID:26075180

  9. The MOZ histone acetyltransferase in epigenetic signaling and disease.

    PubMed

    Carlson, Samuel; Glass, Karen C

    2014-11-01

    The monocytic leukemic zinc finger (MOZ) histone acetyltransferase (HAT) plays a role in acute myeloid leukemia (AML). It functions as a quaternary complex with the bromodomain PHD finger protein 1 (BRPF1), the human Esa1-associated factor 6 homolog (hEAF6), and the inhibitor of growth 5 (ING5). Each of these subunits contain chromatin reader domains that recognize specific post-translational modifications (PTMs) on histone tails, and this recognition directs the MOZ HAT complex to specific chromatin substrates. The structure and function of these epigenetic reader modules has now been elucidated, and a model describing how the cooperative action of these domains regulates HAT activity in response to the epigenetic landscape is proposed. The emerging role of epigenetic reader domains in disease, and their therapeutic potential for many types of cancer is also highlighted. PMID:24633655

  10. KATching-Up on Small Molecule Modulators of Lysine Acetyltransferases.

    PubMed

    Simon, Roman P; Robaa, Dina; Alhalabi, Zayan; Sippl, Wolfgang; Jung, Manfred

    2016-02-25

    The reversible acetylation of lysines is one of the best characterized epigenetic modifications. Its involvement in many key physiological and pathological processes has been documented in numerous studies. Lysine deacetylases (KDACs) and acetyltransferases (KATs) maintain the acetylation equilibrium at histones but also many other proteins. Besides acetylation, also other acyl groups are reversibly installed at the side chain of lysines in proteins. Because of their involvement in disease, KDACs and KATs were proposed to be promising drug targets, and for KDACs, indeed, five inhibitors are now approved for human use. While there is a similar level of evidence for the potential of KATs as drug targets, no inhibitor is in clinical trials. Here, we review the evidence for the diverse roles of KATs in disease pathology, provide an overview of structural features and the available modulators, including those targeting the bromodomains of KATs, and present an outlook. PMID:26701186

  11. Cloning and characterization of a serotonin N-acetyltransferase from a gymnosperm, loblolly pine (Pinus taeda).

    PubMed

    Park, Sangkyu; Byeon, Yeong; Lee, Hyoung Yool; Kim, Young-Soon; Ahn, Taeho; Back, Kyoungwhan

    2014-10-01

    Serotonin N-acetyltransferase (SNAT) is the penultimate enzyme in melatonin biosynthesis in both animals and plants. SNAT catalyzes serotonin into N-acetylserotonin, an immediate precursor for melatonin biosynthesis by N-acetylserotonin methyltransferase (ASMT). We cloned the SNAT gene from a gymnosperm loblolly pine (Pinus teada). The loblolly pine SNAT (PtSNAT) gene encodes 255 amino acids harboring a transit sequence with 67 amino acids and shows 67% amino acid identity with rice SNAT when comparing the mature polypeptide regions. Purified recombinant PtSNAT showed peak activity at 55°C with the K(m) (428 μM) and Vmax (3.9 nmol/min/mg protein) values. As predicted, PtSNAT localized to chloroplasts. The SNAT mRNA was constitutively expressed in all tissues, including leaf, bud, flower, and pinecone, whereas the corresponding protein was detected only in leaf. In accordance with the exclusive SNAT protein expression in leaf, melatonin was detected only in leaf at 0.45 ng per gram fresh weight. Sequence and phylogenetic analysis indicated that the gymnosperm PtSNAT had high homology with SNATs from all plant phyla (even with cyanobacteria), and formed a clade separated from the angiosperm SNATs, suggestive of direct gene transfer from cyanobacteria via endosymbiosis. PMID:25208036

  12. Histone acetyltransferase Hbo1: catalytic activity, cellular abundance, and links to primary cancers.

    PubMed

    Iizuka, Masayoshi; Takahashi, Yoshihisa; Mizzen, Craig A; Cook, Richard G; Fujita, Masatoshi; Allis, C David; Frierson, Henry F; Fukusato, Toshio; Smith, M Mitchell

    2009-05-01

    In addition to the well-characterized proteins that comprise the pre-replicative complex, recent studies suggest that chromatin structure plays an important role in DNA replication initiation. One of these chromatin factors is the histone acetyltransferase (HAT) Hbo1 which is unique among HAT enzymes in that it serves as a positive regulator of DNA replication. However, several of the basic properties of Hbo1 have not been previously examined, including its intrinsic catalytic activity, its molecular abundance in cells, and its pattern of expression in primary cancer cells. Here we show that recombinant Hbo1 can acetylate nucleosomal histone H4 in vitro, with a preference for lysines 5 and 12. Using semi-quantitative western blot analysis, we find that Hbo1 is approximately equimolar with the number of active replication origins in normal human fibroblasts but is an order of magnitude more abundant in both MCF7 and Saos-2 established cancer cell lines. Immunohistochemistry for Hbo1 in 11 primary human tumor types revealed strong Hbo1 protein expression in carcinomas of the testis, ovary, breast, stomach/esophagus, and bladder. PMID:19393168

  13. Reconstitution of active and stoichiometric multisubunit lysine acetyltransferase complexes in insect cells.

    PubMed

    Yan, Kezhi; Wu, Chao-Jung; Pelletier, Nadine; Yang, Xiang-Jiao

    2012-01-01

    Protein lysine acetyltransferases (KATs) catalyze acetylation of the ε-amino group on a specific lysine residue, and this posttranslational modification is important for regulating the function and activities of thousands of proteins in diverse organisms from bacteria to humans. Interestingly, many known KATs exist in multisubunit complexes and complex formation is important for their proper structure, function, and regulation. Thus, it is necessary to reconstitute enzymatically active complexes for studying the relationship between subunits and determining structures of the complexes. Due to inherent limitations of bacterial and mammalian expression systems, baculovirus-mediated protein expression in insect cells has proven useful for assembling such multisubunit complexes. Related to this, we have adopted such an approach for reconstituting active tetrameric complexes of monocytic leukemia zinc (MOZ, finger protein, recently renamed MYST3 or KAT6A) and MOZ-related factor (MORF, also known as MYST4 or KAT6B), two KATs directly linked to development of leukemia and self-renewal of stem cells. Herein, we use these complexes as examples to describe the related procedures. Similar methods have been used for reconstituting active complexes of histone deacetylases, lysine demethylases, and ubiquitin ligases, so this simple approach can be adapted for molecular dissection of various multisubunit complexes. PMID:22113293

  14. Cloning, sequencing, characterisation and implications for vaccine design of the novel dihydrolipoyl acetyltransferase of Neisseria meningitidis.

    PubMed

    Ala' Aldeen, D A; Westphal, A H; De Kok, A; Weston, V; Atta, M S; Baldwin, T J; Bartley, J; Borriello, S P

    1996-12-01

    A lambdaZap-II expression library of Neisseria meningitidis was screened with a rabbit polyclonal antiserum (R-70) raised against c. 70-kDa proteins purified from outer membrane vesicles by elution from preparative SDS-polyacrylamide gels. Selected clones were isolated, further purified, and their recombinant pBluescript SKII plasmids were excised. The cloned DNA insert was sequenced from positive clones and analysed. Four open reading frames (ORFs) were identified, three of which showed a high degree of homology with the pyruvate dehydrogenase (E1p), dihydrolipoyl acetyltransferase (E2p) and dihydrolipoyl dehydrogenase (E3) components of the pyruvate dehydrogenase complex (PDHC) of a number of prokaryotic and eukaryotic species. Sequence analysis indicated that the meningococcal E2p (Men-E2p) contains two N-terminal lipoyl domains, an E1/E3 binding domain and a catalytic domain. The domains are separated by hinge regions rich in alanine, proline and charged residues. Another lipoyl domain with high sequence similarity to the Men-E2p lipoyl domain was found at the N-terminal of the E3 component. A further ORF, coding for a 16.5-kDa protein, was found between the ORFs encoding the E2p and E3 components. The identity and functional characteristics of the expressed and purified heterologous Men-E2p were confirmed as dihydrolipoyl acetyltransferase by immunological and biochemical assays. N-terminal amino-acid analysis confirmed the sequence of the DNA-derived mature protein. Purified Men-E2p reacted with monospecific antisera raised against the whole E2p molecule and against the lipoyl domain of the Azotobacter vinelandii E2p. Conversely, rabbit antiserum raised against Men-E2p reacted with protein extracts of A. vinelandii, Escherichia coli and N. gonorrhoeae and with the lipoyl and catalytic domains of E2p obtained by limited proteolysis. In contrast, the original R-70 antiserum reacted almost exclusively with the lipoyl domain, indicating the strong immunogenicity

  15. Oridonin, a novel lysine acetyltransferases inhibitor, inhibits proliferation and induces apoptosis in gastric cancer cells through p53- and caspase-3-mediated mechanisms

    PubMed Central

    Zhang, Juan; Diao, Hua; Li, Guangming; Xu, Ling; Wang, Ting; Wei, Jue; Meng, Wenying; Ma, Jia-Li; Yu, Heguo; Wang, Yu-Gang

    2016-01-01

    Lysine acetylation has been reported to involve in the pathogenesis of multiple diseases including cancer. In our screening study to identify natural compounds with lysine acetyltransferase inhibitor (KATi) activity, oridonin was found to possess acetyltransferase-inhibitory effects on multiple acetyltransferases including P300, GCN5, Tip60, and pCAF. In gastric cancer cells, oridonin treatment inhibited cell proliferation in a concentration-dependent manner and down-regulated the expression of p53 downstream genes, whereas p53 inhibition by PFT-α reversed the antiproliferative effects of oridonin. Moreover, oridonin treatment induced cell apoptosis, increased the levels of activated caspase-3 and caspase-9, and decreased the mitochondrial membrane potential in gastric cancer cells in a concentration-dependent manner. Caspase-3 inhibition by Ac-DEVD-CHO reversed the proapoptosis effect of oridonin. In conclusion, our study identified oridonin as a novel KATi and demonstrated its tumor suppressive effects in gastric cancer cells at least partially through p53-and caspase-3-mediated mechanisms. PMID:26980707

  16. Connecting developmental constructions to the internet: identity presentation and sexual exploration in online teen chat rooms.

    PubMed

    Subrahmanyam, Kaveri; Smahel, David; Greenfield, Patricia

    2006-05-01

    The authors examined the online construction of identity and sexuality in a large sample of conversations from monitored and unmonitored teen chat rooms. More than half of the 583 participants (identified by a distinct screen name) communicated identity information, most frequently gender. In this way, participants compensated for the text-based chat environment by providing information about themselves that would be visible and obvious in face-to-face communication. Sexual themes constituted 5% of all utterances (1 sexual comment per minute); bad or obscene language constituted 3% of the sample (1 obscenity every 2 minutes). Participants who self-identified as female produced more implicit sexual communication, participants who self-identified as male produced more explicit sexual communication. The protected environment of monitored chat (hosts who enforce basic behavioral rules) contained an environment with less explicit sexuality and fewer obscenities than the freer environment of unmonitored chat. These differences were attributable both to the monitoring process itself and to the differing populations attracted to each type of chat room (monitored: more participants self-identified as younger and female; unmonitored: more participants self-identified as older and male). PMID:16756432

  17. Narrative discourse and sociocognitive abilities of a child with Cri-du-Chat syndrome.

    PubMed

    Albano, Stefania; Piccardi, Laura; Pizzamiglio, Maria Rosa; Volpe, Cristino; D'Amico, Simonetta

    2013-01-01

    The authors investigated narrative competence, sociocognitive abilities and emotion comprehension in a 9-year-old child (FS) with Cri-du-Chat Syndrome (CdCS) who had only a mild mental delay and relatively preserved language. Considering that the production of narratives is a major step in development and in the acquisition of learning skills related to conceptual, linguistic, structural, and pragmatic knowledge, and in the development of psychological lexicon, that is, the ability to use theory of mind (ToM) processes also in atypical development, this case provided an opportunity to study aspects of this genetic syndrome never investigated before. The authors found that the child's performance on different stories was comparable to that of chronological age controls for several narrative and emotional competences and even better than that of mental age controls. However, her ability to reason was still incomplete according ToM; in fact, FS was able to express her mental states, but she was unable to understand emotions, specifically mixed emotions. This finding suggests that in CdCS children with a well-developed language narrative and emotional competence could be a point of strength for improving their social skills with important effects on their familiar and school life. Also in CdCS children with the typical poor developed language, the narrative discourse could be introduced in their communication by means of any type of alternative language (i.e., sign language or augmentative and alternative communication) to improve their social abilities and to reduce behavioral disorders due to the difficulty in expressing their personal experiences. PMID:23534097

  18. Comparative genomic and phylogenetic investigation of the xenobiotic metabolizing arylamine N-acetyltransferase enzyme family

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Arylamine N-acetyltransferases (NATs) are xenobiotic metabolizing enzymes characterized in several bacteria and eukaryotic organisms. We report a comprehensive phylogenetic analysis employing an exhaustive dataset of NAT-homologous sequences recovered through inspection of 2445 genomes. We describe ...

  19. Enhancer of Acetyltransferase Chameau (EAChm) Is a Novel Transcriptional Co-Activator

    PubMed Central

    Imamura, Yuko; Higashi, Miki; Yoneda, Mitsuhiro; Ito, Takashi

    2015-01-01

    Acetylation of nucleosomal histones by diverse histone acetyltransferases (HAT) plays pivotal roles in many cellular events. Discoveries of novel HATs and HAT related factors have provided new insights to understand the roles and mechanisms of histone acetylation. In this study, we identified prominent Histone H3 acetylation activity in vitro and purified its activity, showing that it is composed of the MYST acetyltransferase Chameau and Enhancer of the Acetyltransferase Chameau (EAChm) family. EAChm is a negatively charged acidic protein retaining aspartate and glutamate. Furthermore, we identified that Chameau and EAChm stimulate transcription in vitro together with purified general transcription factors. In addition, RNA-seq analysis of Chameu KD and EAChm KD S2 cells suggest that Chameau and EAChm regulate transcription of common genes in vivo. Our results suggest that EAChm regulates gene transcription in Drosophila embryos by enhancing Acetyltransferase Chameau activity. PMID:26555228

  20. The Q-CHAT (Quantitative CHecklist for Autism in Toddlers): A Normally Distributed Quantitative Measure of Autistic Traits at 18-24 Months of Age--Preliminary Report

    ERIC Educational Resources Information Center

    Allison, Carrie; Baron-Cohen, Simon; Wheelwright, Sally; Charman, Tony; Richler, Jennifer; Pasco, Greg; Brayne, Carol

    2008-01-01

    We report a major revision of the CHecklist for Autism in Toddlers (CHAT). This "quantitative" CHAT (Q-CHAT) contains 25 items, scored on a 5 point scale (0-4). The Q-CHAT was completed by parents of n = 779 unselected toddlers (mean age 21 months) and n = 160 toddlers and preschoolers (mean age 44 months) with an Autism Spectrum Condition (ASC).…

  1. [Dental education for college students based on WeChat public platform].

    PubMed

    Chen, Chuan-Jun; Sun, Tan

    2016-06-01

    The authors proposed a model for dental education based on WeChat public platform. In this model, teachers send various kinds of digital teaching information such as PPT,word and video to the WeChat public platform and students share the information for preview before class and differentiate the key-point knowledge from those information for in-depth learning in class. Teachers also send reference materials for expansive learning after class. Questionaire through the WeChat public platform is used to evaluate teaching effect of teachers and improvement may be taken based on the feedback questionnaire. A discussion and interaction based on WeCchat between students and teacher can be aroused on a specific topic to reach a proper solution. With technique development of mobile terminal, mobile class will come true in near future. PMID:27609397

  2. Autonomy in nursing students process of knowledge construction: the educational chat as a teaching tool.

    PubMed

    da Silva, Ana Paula Scheffer Schell; Pedro, Eva Néri Rubim

    2010-01-01

    This documental study has the qualitative approach of a case study. It analyzes how autonomy has been developed in nursing students process of knowledge construction, in a context mediated by the use of educational chat in Learning Management Systems (LMS). The analyzed materials were eight discussions promoted by students, professors, and monitors in the chat session of TelEduc LMS. The software NVivo was used to categorize data and Content Analysis for the analysis of information. Data analysis used Freire as a reference point, revealing that nursing students need to develop their autonomy by acknowledging their incompleteness. Professors can aid this process by problematizing and developing critical dialogical relations. The potential of the educational chat as a pedagogical tool is highlighted because it encourages students to autonomously seek knowledge. PMID:20549120

  3. Interactions between Text Chat and Audio Modalities for L2 Communication and Feedback in the Synthetic World "Second Life"

    ERIC Educational Resources Information Center

    Wigham, Ciara R.; Chanier, Thierry

    2015-01-01

    This paper reports on a study of the interactions between text chat and audio modalities in L2 communication in a synthetic (virtual) world and observes whether the text chat modality was used for corrective feedback and the characteristics of the latter. This is examined within the context of a hybrid content and language integrated learning…

  4. Observations of Chat Room Conversations on the Internet: Implications for Educators Addressing the Needs of Female Adolescents

    ERIC Educational Resources Information Center

    Sanger, Dixie; Ritzman, Mitzi; LaCost, Barbara; Stofer, Keri; Long, Amie; Grady, Marilyn

    2005-01-01

    This qualitative study explored the meanings of chat room conversations through observations of teenagers using the Internet. Adolescent girls were a focus because of their shaky sense of self. Participants in ten chat rooms included 534 individuals. Six themes, emerging from analyzing 2526 utterances [descriptive statements], included (a)…

  5. 77 FR 49059 - Requested Administrative Waiver of the Coastwise Trade Laws: Vessel CHAT DE MER; Invitation for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-15

    ... published on April 11, 2000 (65 FR 19477-78). By Order of the Maritime Administrator. Dated: August 9, 2012... Maritime Administration Requested Administrative Waiver of the Coastwise Trade Laws: Vessel CHAT DE MER... of the vessel CHAT DE MER is: Intended Commercial Use of Vessel: Primarily carrying passengers...

  6. Bringing Japan and Taiwan Closer Electronically: A Look at an Intercultural Online Synchronic Chat Task and Its Effect on Motivation

    ERIC Educational Resources Information Center

    Freiermuth, Mark R.; Huang, Hsin-chou

    2012-01-01

    This study examines the motivation of 20 Japanese students of English as a foreign language (EFL) who chatted electronically with 19 Taiwanese EFL students using online synchronous chat software. In particular, we were interested in four factors that affect task-based motivation: the willingness to communicate, task attractiveness, task…

  7. Effects of Face-to-Face versus Chat Communication on Performance in a Collaborative Inquiry Modeling Task

    ERIC Educational Resources Information Center

    Sins, Patrick H. M.; Savelsbergh, Elwin R.; van Joolingen, Wouter R.; van Hout-Wolters, Bernadette H. A. M.

    2011-01-01

    In many contemporary collaborative inquiry learning environments, chat is being used as a means for communication. Still, it remains an open issue whether chat communication is an appropriate means to support the deep reasoning process students need to perform in such environments. Purpose of the present study was to compare the impact of chat…

  8. When Is It Appropriate to Talk? Managing Overlapping Talk in Multi-Participant Voice-Based Chat Rooms

    ERIC Educational Resources Information Center

    Jenks, Christopher Joseph

    2009-01-01

    There has been extensive reporting on the interactional characteristics of multi-participant text-based chat rooms. In these chat rooms there are several students typing at the same time, often on more than one topic. As a result, it is not uncommon to see multiple overlapping utterances. Despite these communicative challenges, research suggests…

  9. Chat (Catha edulis): a socio economic crop in Harar Region, Eastern Ethiopia.

    PubMed

    Kandari, Laxman S; Yadav, Hiranmai R; Thakur, Ashok K; Kandari, Tripti

    2014-01-01

    Chat (Catha edulis) is an important perennial crop and its leaves are chewed for a stimulating effect. It is widely cultivated in the Ethiopian highlands of Oromia region and is figured as Ethiopia's second largest foreign exchange earner. Its cultivation accounts for about 70% of farmer's income in the study area. The common effect of its consumption leads to insomnia, a condition that the users sometimes try to overcome with sedatives or alcohol. The present study is an attempt to survey and assess the impact of crop on the community. It has been observed to implicate health problems, reduces savings and nutritional standards of the family members. The chat yields in the area ranges from 1500-1800 kg/ha through monoculture. During the study, the average monthly income of the family practicing chat cultivation was from Birr 8, 533.00 to 13, 166.00 kg/ha per year in Baate and Genede cultivating areas. When the average cost per/ha was rupees 60/kg. The present study shows that during the recent past, leaf consumption has increased significantly. Chat growers are not only producers but also traders and consumers. Its consumption has become a widespread habit from secondary schools. Highest number of consumers was found to be among drivers followed by students and shopkeepers. The consumption of the plant is not considered a taboo but on contrary a status symbol in the region. It has no legal or moral implications and is considered as a part of custom and habit of local people. High value cash crop like vegetables and orchard fruits needs to be used as a replacement for chat which could be a regular source of income to farmers. Alternative sources of income for farmers needs to be scientifically worked out and proposed keeping in view the proportion of agricultural land reserved under chat cultivation and to increase the production of food grains being produced. PMID:25332879

  10. Cloning and characterization of two genes coding for the histone acetyltransferases, Elp3 and Mof, in brown planthopper (BPH), Nilaparvata lugens (Stål).

    PubMed

    Zhu, Youli; Xie, Zhijuan; Wang, Jian; Liu, Yaping; Wang, Jianjun

    2013-01-15

    Histone acetylation is a vital mechanism for the post-translational modifications of chromatin components. Histone acetyltransferases (HATs) are critical elements that determine histone acetylation and regulate chromatin dynamics and gene expression. While histone acetyltransferases have been well studied in mammals and Drosophila melanogaster, information from agriculturally important insect pests is still limited. In our effort to understand the epigenetic mechanisms regulating development in the brown planthopper, Nilaparvata lugens (Stål) (Hemiptera: Geometroidea), a major rice pest in many parts of Asia, two full-length cDNA sequences encoding HAT members of the GNAT and MYST family, namely NlElp3 and NlMof, respectively, were isolated and structurally and phylogenetically characterized. The NlElp3 contains an open reading frame (ORF) of 1656bp encoding a protein of 551 amino acids. The NlMof contains a 1353bp ORF encoding a protein of 450 amino acids. Sequence analysis showed that NlElp3 contains GNAT-type HAT domain and Radical SAM domain, and NlMof contains chromodomain and MOZ-SAS acetyltransferase domain. Multiple sequence alignments showed that NlElp3 and NlMof have high amino acid sequence identity with other insect homologues. Expression analysis of the NlElp3 and NlMof revealed significant differences in mRNA expression levels among N. lugens developmental stages, suggesting that HAT activities of NlElp3 and NlMof may be controlled, at least in part, by their developmental regulation. Remarkably, the mRNA expression levels of NlElp3 and NlMof in female adults were significantly higher than that in male adults, supporting an important role for both genes in female reproductive function in N. lugens. PMID:23142031

  11. The acetyltransferase Tip60 contributes to mammary tumorigenesis by modulating DNA repair

    PubMed Central

    Bassi, C; Li, Y-T; Khu, K; Mateo, F; Baniasadi, P S; Elia, A; Mason, J; Stambolic, V; Pujana, M A; Mak, T W; Gorrini, C

    2016-01-01

    The acetyltransferase Tip60/Kat5 acetylates both histone and non-histone proteins, and is involved in a variety of biological processes. By acetylating p53, Tip60 controls p53-dependent transcriptional activity and so is implicated as a tumor suppressor. However, many breast cancers with low Tip60 also show p53 mutation, implying that Tip60 has a tumor suppressor function independent of its acetylation of p53. Here, we show in a p53-null mouse model of sporadic invasive breast adenocarcinoma that heterozygosity for Tip60 deletion promotes mammary tumorigenesis. Low Tip60 reduces DNA repair in normal and tumor mammary epithelial cells, both under resting conditions and following genotoxic stress. We demonstrate that Tip60 controls homologous recombination (HR)-directed DNA repair, and that Tip60 levels correlate inversely with a gene expression signature associated with defective HR-directed DNA repair. In human breast cancer data sets, Tip60 mRNA is downregulated, with low Tip60 levels correlating with p53 mutations in basal-like breast cancers. Our findings indicate that Tip60 is a novel breast tumor suppressor gene whose loss results in genomic instability leading to cancer formation. PMID:26915295

  12. The Aspergillus flavus Histone Acetyltransferase AflGcnE Regulates Morphogenesis, Aflatoxin Biosynthesis, and Pathogenicity

    PubMed Central

    Lan, Huahui; Sun, Ruilin; Fan, Kun; Yang, Kunlong; Zhang, Feng; Nie, Xin Y.; Wang, Xiunai; Zhuang, Zhenhong; Wang, Shihua

    2016-01-01

    Histone acetyltransferases (HATs) help regulate fungal development and the production of secondary metabolites. In this study, we determined that the HAT AflGcnE influenced morphogenesis and aflatoxin biosynthesis in Aspergillus flavus. We observed that AflGcnE localized to the nucleus and cytoplasm during the conidial production and germination stages, while it was located mainly in the nucleus during the hyphal development stage. Deletion of AflgcnE inhibited the growth of A. flavus and decreased the hydrophobicity of the cell surface. The ΔAflgcnE mutant exhibited a lack of asexual sporulation and was unable to generate sclerotia. Additionally, AflgcnE was required to maintain cell wall integrity and genotoxic stress responses. Importantly, the ΔAflgcnE mutant did not produce aflatoxins, which was consistent with a significant down-regulation of aflatoxin gene expression levels. Furthermore, our data revealed that AflgcnE is a pathogenicity factor required for colonizing maize seeds. In summary, we revealed that A. flavus AflGcnE is crucial for morphological development, aflatoxin biosynthesis, stress responses, and pathogenicity. Our findings help clarify the functional divergence of GcnE orthologs, and may provide a possible target for controlling A. flavus infections of agriculturally important crops. PMID:27625637

  13. The Aspergillus flavus Histone Acetyltransferase AflGcnE Regulates Morphogenesis, Aflatoxin Biosynthesis, and Pathogenicity.

    PubMed

    Lan, Huahui; Sun, Ruilin; Fan, Kun; Yang, Kunlong; Zhang, Feng; Nie, Xin Y; Wang, Xiunai; Zhuang, Zhenhong; Wang, Shihua

    2016-01-01

    Histone acetyltransferases (HATs) help regulate fungal development and the production of secondary metabolites. In this study, we determined that the HAT AflGcnE influenced morphogenesis and aflatoxin biosynthesis in Aspergillus flavus. We observed that AflGcnE localized to the nucleus and cytoplasm during the conidial production and germination stages, while it was located mainly in the nucleus during the hyphal development stage. Deletion of AflgcnE inhibited the growth of A. flavus and decreased the hydrophobicity of the cell surface. The ΔAflgcnE mutant exhibited a lack of asexual sporulation and was unable to generate sclerotia. Additionally, AflgcnE was required to maintain cell wall integrity and genotoxic stress responses. Importantly, the ΔAflgcnE mutant did not produce aflatoxins, which was consistent with a significant down-regulation of aflatoxin gene expression levels. Furthermore, our data revealed that AflgcnE is a pathogenicity factor required for colonizing maize seeds. In summary, we revealed that A. flavus AflGcnE is crucial for morphological development, aflatoxin biosynthesis, stress responses, and pathogenicity. Our findings help clarify the functional divergence of GcnE orthologs, and may provide a possible target for controlling A. flavus infections of agriculturally important crops. PMID:27625637

  14. Mechanistic and Structural Analysis of Drosophila melanogaster Arylalkylamine N-Acetyltransferases

    PubMed Central

    2015-01-01

    Arylalkylamine N-acetyltransferase (AANAT) catalyzes the penultimate step in the biosynthesis of melatonin and other N-acetylarylalkylamides from the corresponding arylalkylamine and acetyl-CoA. The N-acetylation of arylalkylamines is a critical step in Drosophila melanogaster for the inactivation of the bioactive amines and the sclerotization of the cuticle. Two AANAT variants (AANATA and AANATB) have been identified in D. melanogaster, in which AANATA differs from AANATB by the truncation of 35 amino acids from the N-terminus. We have expressed and purified both D. melanogaster AANAT variants (AANATA and AANATB) in Escherichia coli and used the purified enzymes to demonstrate that this N-terminal truncation does not affect the activity of the enzyme. Subsequent characterization of the kinetic and chemical mechanism of AANATA identified an ordered sequential mechanism, with acetyl-CoA binding first, followed by tyramine. We used a combination of pH–activity profiling and site-directed mutagenesis to study prospective residues believed to function in AANATA catalysis. These data led to an assignment of Glu-47 as the general base in catalysis with an apparent pKa of 7.0. Using the data generated for the kinetic mechanism, structure–function relationships, pH–rate profiles, and site-directed mutagenesis, we propose a chemical mechanism for AANATA. PMID:25406072

  15. The acetyltransferase Tip60 contributes to mammary tumorigenesis by modulating DNA repair.

    PubMed

    Bassi, C; Li, Y-T; Khu, K; Mateo, F; Baniasadi, P S; Elia, A; Mason, J; Stambolic, V; Pujana, M A; Mak, T W; Gorrini, C

    2016-07-01

    The acetyltransferase Tip60/Kat5 acetylates both histone and non-histone proteins, and is involved in a variety of biological processes. By acetylating p53, Tip60 controls p53-dependent transcriptional activity and so is implicated as a tumor suppressor. However, many breast cancers with low Tip60 also show p53 mutation, implying that Tip60 has a tumor suppressor function independent of its acetylation of p53. Here, we show in a p53-null mouse model of sporadic invasive breast adenocarcinoma that heterozygosity for Tip60 deletion promotes mammary tumorigenesis. Low Tip60 reduces DNA repair in normal and tumor mammary epithelial cells, both under resting conditions and following genotoxic stress. We demonstrate that Tip60 controls homologous recombination (HR)-directed DNA repair, and that Tip60 levels correlate inversely with a gene expression signature associated with defective HR-directed DNA repair. In human breast cancer data sets, Tip60 mRNA is downregulated, with low Tip60 levels correlating with p53 mutations in basal-like breast cancers. Our findings indicate that Tip60 is a novel breast tumor suppressor gene whose loss results in genomic instability leading to cancer formation. PMID:26915295

  16. Mechanistic and structural analysis of Drosophila melanogaster arylalkylamine N-acetyltransferases.

    PubMed

    Dempsey, Daniel R; Jeffries, Kristen A; Bond, Jason D; Carpenter, Anne-Marie; Rodriguez-Ospina, Santiago; Breydo, Leonid; Caswell, K Kenneth; Merkler, David J

    2014-12-16

    Arylalkylamine N-acetyltransferase (AANAT) catalyzes the penultimate step in the biosynthesis of melatonin and other N-acetylarylalkylamides from the corresponding arylalkylamine and acetyl-CoA. The N-acetylation of arylalkylamines is a critical step in Drosophila melanogaster for the inactivation of the bioactive amines and the sclerotization of the cuticle. Two AANAT variants (AANATA and AANATB) have been identified in D. melanogaster, in which AANATA differs from AANATB by the truncation of 35 amino acids from the N-terminus. We have expressed and purified both D. melanogaster AANAT variants (AANATA and AANATB) in Escherichia coli and used the purified enzymes to demonstrate that this N-terminal truncation does not affect the activity of the enzyme. Subsequent characterization of the kinetic and chemical mechanism of AANATA identified an ordered sequential mechanism, with acetyl-CoA binding first, followed by tyramine. We used a combination of pH-activity profiling and site-directed mutagenesis to study prospective residues believed to function in AANATA catalysis. These data led to an assignment of Glu-47 as the general base in catalysis with an apparent pKa of 7.0. Using the data generated for the kinetic mechanism, structure-function relationships, pH-rate profiles, and site-directed mutagenesis, we propose a chemical mechanism for AANATA. PMID:25406072

  17. Arylamine N-acetyltransferase activity in bronchial epithelial cells and its inhibition by cellular oxidants

    SciTech Connect

    Dairou, Julien; Petit, Emile; Ragunathan, Nilusha; Baeza-Squiban, Armelle; Marano, Francelyne; Dupret, Jean-Marie; Rodrigues-Lima, Fernando

    2009-05-01

    Bronchial epithelial cells express xenobiotic-metabolizing enzymes (XMEs) that are involved in the biotransformation of inhaled toxic compounds. The activities of these XMEs in the lung may modulate respiratory toxicity and have been linked to several diseases of the airways. Arylamine N-acetyltransferases (NAT) are conjugating XMEs that play a key role in the biotransformation of aromatic amine pollutants such as the tobacco-smoke carcinogens 4-aminobiphenyl (4-ABP) and {beta}-naphthylamine ({beta}-NA). We show here that functional human NAT1 or its murine counterpart Nat2 are present in different lung epithelial cells i.e. Clara cells, type II alveolar cells and bronchial epithelial cells, thus indicating that inhaled aromatic amines may undergo NAT-dependent biotransformation in lung epithelium. Exposure of these cells to pathophysiologically relevant amounts of oxidants known to contribute to lung dysfunction, such as H{sub 2}O{sub 2} or peroxynitrite, was found to impair the NAT1/Nat2-dependent cellular biotransformation of aromatic amines. Genetic and non genetic impairment of intracellular NAT enzyme activities has been suggested to compromise the important detoxification pathway of aromatic amine N-acetylation and subsequently to contribute to an exacerbation of untoward effects of these pollutants on health. Our study suggests that oxidative/nitroxidative stress in lung epithelial cells, due to air pollution and/or inflammation, could contribute to local and/or systemic dysfunctions through the alteration of the functions of pulmonary NAT enzymes.

  18. Characterization of two acetyltransferase genes in the pyripyropene biosynthetic gene cluster from Penicillium coprobium

    PubMed Central

    Hu, Jie; Furutani, Ayako; Yamamoto, Kentaro; Oyama, Kazuhiko; Mitomi, Masaaki; Anzai, Hiroyuki

    2014-01-01

    Pyripyropenes potently and selectively inhibit acyl-CoA:cholesterol acyltransferase 2 (ACAT-2). Among multiple isomers of pyripyropene (A to R), pyripyropene A (PyA) has insecticidal properties in addition to its growth inhibition properties against human umbilical vein endothelial cells. Based on the predicted biosynthetic gene cluster of pyripyropene A, two genes (ppb8 and ppb9) encoding two acetyltransferases (ATs) were separately isolated and introduced into the model fungus Aspergillus oryzae, using the protoplast–polyethylene glycol method. The bioconversion of certain predicted intermediates in the transformants revealed the manner by which acetylation occurred in the biosynthetic pathway by the products expressed by these two genes (AT-1 and AT-2). The acetylated products detected by high-performance liquid chromatography (HPLC) in the extracts from AT-1 and AT-2 transformant clones were not present in the extract from the transformant clone with an empty vector. The HLPC charts of each bioconversion study exhibited high peaks at 12, 10.5 and 9 min, respectively. Further ultraviolet absorption and mass spectrometry analyses identified the products as PyE, PyO and PyA, respectively. AT-1 acetylated the C-1 of deacetyl-pyripyropene E (deAc-PyE), while AT-2 played an active role in acetylating the C-11 of 11-deAc-PyO and C-7 of deAc-PyA at two different steps of the biosynthetic pathway. PMID:26019565

  19. Histone acetyltransferases and histone deacetylases in B- and T-cell development, physiology and malignancy

    PubMed Central

    Haery, Leila; Thompson, Ryan C.; Gilmore, Thomas D.

    2015-01-01

    The development of B and T cells from hematopoietic precursors and the regulation of the functions of these immune cells are complex processes that involve highly regulated signaling pathways and transcriptional control. The signaling pathways and gene expression patterns that give rise to these developmental processes are coordinated, in part, by two opposing classes of broad-based enzymatic regulators: histone acetyltransferases (HATs) and histone deacetylases (HDACs). HATs and HDACs can modulate gene transcription by altering histone acetylation to modify chromatin structure, and by regulating the activity of non-histone substrates, including an array of immune-cell transcription factors. In addition to their role in normal B and T cells, dysregulation of HAT and HDAC activity is associated with a variety of B- and T-cell malignancies. In this review, we describe the roles of HATs and HDACs in normal B- and T-cell physiology, describe mutations and dysregulation of HATs and HDACs that are implicated lymphoma and leukemia, and discuss HAT and HDAC inhibitors that have been explored as treatment options for leukemias and lymphomas. PMID:26124919

  20. Improvement of L-arginine production by overexpression of a bifunctional ornithine acetyltransferase in Corynebacterium crenatum.

    PubMed

    Dou, Wenfang; Xu, Meijuan; Cai, Dongmei; Zhang, Xiaomei; Rao, Zhiming; Xu, Zhenghong

    2011-10-01

    Ornithine acetyltransferase (EC 2.3.1.35; OATase) gene (argJ) from the L-arginine-producing mutant Corynebacterium crenatum SYPA5-5 was cloned, sequenced, and expressed in Escherichia coli BL21 (DE3). Analysis of the argJ sequence revealed that the argJ coded a polypeptide of 388 amino acids with a calculated molecular weight of 39.7 kDa. In this study, the function of the OATase (argJ) of C. crenatum SYPA5-5 has been identified as a conserved ATML sequence for the autolysis of the protein to α- and β-subunits. When the argJ regions corresponding to the α- and β-subunits were cloned and expressed separately in E. coli BL21, OATase activities were abolished. At the same time, a functional study revealed that OATase from C. crenatum SYPA5-5 was a bifunctional enzyme with the functions of acetylglutamate synthase (EC 2.3.1.1, NAGS) and acetylornithine deacetylase (EC 3.5.1.16, AOase) activities. In order to investigate the effects of the overexpression of the argJ gene on L: -arginine production, the argJ gene was inserted into pJCtac to yield the recombinant shuttle plasmid pJCtac-argJ and then transformed into C. crenatum SYPA5-5. The results showed that the engineered strains could not only express more OATase (90.9%) but also increase the production of L: -arginine significantly (16.8%). PMID:21785983

  1. Effect of arylamine acetyltransferase Nat3 gene knockout on N-acetylation in the mouse.

    PubMed

    Sugamori, K S; Brenneman, D; Wong, S; Gaedigk, A; Yu, V; Abramovici, H; Rozmahel, R; Grant, D M

    2007-07-01

    Arylamine N-acetyltransferases (NAT) catalyze the biotransformation of many important arylamine drugs and procarcinogens. NAT can either detoxify or activate procarcinogens, complicating the manner in which these enzymes may participate in enhancing or preventing toxic responses to particular agents. Mice possess three NAT isoenzymes: Nat1, Nat2, and Nat3. Whereas Nat1 and Nat2 can efficiently acetylate many arylamines, few substrates appear to be appreciably metabolized by Nat3. We generated a Nat3 knockout mouse strain and used it along with our double Nat1/2(-/-) knockout strain to further investigate the functional role of Nat3. Nat3(-/-) mice showed normal viability and reproductive capacity. Nat3 expression was very low in wild-type animals and completely undetectable in Nat3(-/-) mice. In contrast, greatly elevated expression of Nat3 transcript was observed in Nat1/2(-/-) mice. We used a transcribed marker polymorphism approach to establish that the increased expression of Nat3 in Nat1/2(-/-) mice is a positional artifact of insertion of the phosphoglycerate kinase-neomycin resistance cassette in place of the Nat1/Nat2 gene region and upstream of the intact Nat3 gene, rather than a biological compensatory mechanism. Despite the increase in Nat3 transcript, the N-acetylation of p-aminosalicylate, sulfamethazine, 2-aminofluorene, and 4-aminobiphenyl was undetectable either in vivo or in vitro in Nat1/2(-/-) animals. In parallel, no difference was observed in the in vivo clearance or in vitro metabolism of any of these substrates between wild-type and Nat3(-/-) mice. Thus, Nat3 is unlikely to play a significant role in the N-acetylation of arylamines either in wild-type mice or in mice lacking Nat1 and Nat2 activities. PMID:17403913

  2. Histone acetyltransferase activity of yeast Gcn5p is required for the activation of target genes in vivo

    PubMed Central

    Kuo, Min-Hao; Zhou, Jianxin; Jambeck, Per; Churchill, Mair E.A.; Allis, C. David

    1998-01-01

    Gcn5p is a transcriptional coactivator required for correct expression of various genes in yeast. Several transcriptional regulators, including Gcn5p, possess intrinsic histone acetyltransferase (HAT) activity in vitro. However, whether the HAT activity of any of these proteins is required for gene activation remains unclear. Here, we demonstrate that the HAT activity of Gcn5p is critical for transcriptional activation of target genes in vivo. Core histones are hyperacetylated in cells overproducing functional Gcn5p, and promoters of Gcn5p-regulated genes are associated with hyperacetylated histones upon activation by low-copy Gcn5p. Point mutations within the Gcn5p catalytic domain abolish both promoter-directed histone acetylation and Gcn5p-mediated transcriptional activation. These data provide the first in vivo evidence that promoter-specific histone acetylation, catalyzed by functional Gcn5p, plays a critical role in gene activation. PMID:9499399

  3. Reconstruction of N-acetyltransferase 2 haplotypes using PHASE.

    PubMed

    Golka, Klaus; Blaszkewicz, Meinolf; Samimi, Mirabutaleb; Bolt, Hermann M; Selinski, Silvia

    2008-04-01

    The genotyping of N-acetyltransferase 2 (NAT2) by PCR/RFLP methods yields in a considerable percentage ambiguous results. To resolve this methodical problem a statistical approach was applied. PHASE v2.1.1, a statistical program for haplotype reconstruction was used to estimate haplotype pairs from NAT2 genotyping data, obtained by the analysis of seven single nucleotide polymorphisms relevant for Caucasians. In 1,011 out of 2,921 (35%) subjects the haplotype pairs were clearcut by the PCR/RFLP data only. For the majority of the data the applied method resulted in a multiplicity (2-4) of possible haplotype pairs. Haplotype reconstruction using PHASE v2.1.1 cleared this ambiguity in all cases but one, where an alternative haplotype pair was considered with a probability of 0.029. The estimation of the NAT2 haplotype is important because the assignment of the NAT2 alleles *12A, *12B, *12C or *13 to the rapid or slow NAT2 genotype has been discussed controversially. A clear assignment is indispensable in surveys of human bladder cancer caused by aromatic amine exposures. In conclusion, PHASE v2.1.1 software allowed an unambiguous haplotype reconstruction in 2,920 of 2,921 cases (>99.9%). PMID:17879084

  4. Histone acetyltransferase inhibitors block neuroblastoma cell growth in vivo

    PubMed Central

    Gajer, J M; Furdas, S D; Gründer, A; Gothwal, M; Heinicke, U; Keller, K; Colland, F; Fulda, S; Pahl, H L; Fichtner, I; Sippl, W; Jung, M

    2015-01-01

    We have previously described novel histone acetyltransferase (HAT) inhibitors that block neuroblastoma cell growth in vitro. Here we show that two selected pyridoisothiazolone HAT inhibitors, PU139 and PU141, induce cellular histone hypoacetylation and inhibit growth of several neoplastic cell lines originating from different tissues. Broader in vitro selectivity profiling shows that PU139 blocks the HATs Gcn5, p300/CBP-associated factor (PCAF), CREB (cAMP response element-binding) protein (CBP) and p300, whereas PU141 is selective toward CBP and p300. The pan-inhibitor PU139 triggers caspase-independent cell death in cell culture. Both inhibitors block growth of SK-N-SH neuroblastoma xenografts in mice and the PU139 was shown to synergize with doxorubicin in vivo. The latter also reduces histone lysine acetylation in vivo at concentrations that block neoplastic xenograft growth. This is one of the very few reports on hypoacetylating agents with in vivo anticancer activity. PMID:25664930

  5. Obesity and lipid stress inhibit carnitine acetyltransferase activity.

    PubMed

    Seiler, Sarah E; Martin, Ola J; Noland, Robert C; Slentz, Dorothy H; DeBalsi, Karen L; Ilkayeva, Olga R; An, Jie; Newgard, Christopher B; Koves, Timothy R; Muoio, Deborah M

    2014-04-01

    Carnitine acetyltransferase (CrAT) is a mitochondrial matrix enzyme that catalyzes the interconversion of acetyl-CoA and acetylcarnitine. Emerging evidence suggests that this enzyme functions as a positive regulator of total body glucose tolerance and muscle activity of pyruvate dehydrogenase (PDH), a mitochondrial enzyme complex that promotes glucose oxidation and is feedback inhibited by acetyl-CoA. Here, we used tandem mass spectrometry-based metabolic profiling to identify a negative relationship between CrAT activity and muscle content of lipid intermediates. CrAT specific activity was diminished in muscles from obese and diabetic rodents despite increased protein abundance. This reduction in enzyme activity was accompanied by muscle accumulation of long-chain acylcarnitines (LCACs) and acyl-CoAs and a decline in the acetylcarnitine/acetyl-CoA ratio. In vitro assays demonstrated that palmitoyl-CoA acts as a direct mixed-model inhibitor of CrAT. Similarly, in primary human myocytes grown in culture, nutritional and genetic manipulations that promoted mitochondrial influx of fatty acids resulted in accumulation of LCACs but a pronounced decrease of CrAT-derived short-chain acylcarnitines. These results suggest that lipid-induced antagonism of CrAT might contribute to decreased PDH activity and glucose disposal in the context of obesity and diabetes. PMID:24395925

  6. Inhibition of aminoglycoside acetyltransferase resistance enzymes by metal salts.

    PubMed

    Li, Yijia; Green, Keith D; Johnson, Brooke R; Garneau-Tsodikova, Sylvie

    2015-07-01

    Aminoglycosides (AGs) are clinically relevant antibiotics used to treat infections caused by both Gram-negative and Gram-positive bacteria, as well as Mycobacteria. As with all current antibacterial agents, resistance to AGs is an increasing problem. The most common mechanism of resistance to AGs is the presence of AG-modifying enzymes (AMEs) in bacterial cells, with AG acetyltransferases (AACs) being the most prevalent. Recently, it was discovered that Zn(2+) metal ions displayed an inhibitory effect on the resistance enzyme AAC(6')-Ib in Acinetobacter baumannii and Escherichia coli. In this study, we explore a wide array of metal salts (Mg(2+), Cr(3+), Cr(6+), Mn(2+), Co(2+), Ni(2+), Cu(2+), Zn(2+), Cd(2+), and Au(3+) with different counter ions) and their inhibitory effect on a large repertoire of AACs [AAC(2')-Ic, AAC(3)-Ia, AAC(3)-Ib, AAC(3)-IV, AAC(6')-Ib', AAC(6')-Ie, AAC(6')-IId, and Eis]. In addition, we determine the MIC values for amikacin and tobramycin in combination with a zinc pyrithione complex in clinical isolates of various bacterial strains (two strains of A. baumannii, three of Enterobacter cloacae, and four of Klebsiella pneumoniae) and one representative of each species purchased from the American Type Culture Collection. PMID:25941215

  7. Inhibition of Aminoglycoside Acetyltransferase Resistance Enzymes by Metal Salts

    PubMed Central

    Li, Yijia; Green, Keith D.; Johnson, Brooke R.

    2015-01-01

    Aminoglycosides (AGs) are clinically relevant antibiotics used to treat infections caused by both Gram-negative and Gram-positive bacteria, as well as Mycobacteria. As with all current antibacterial agents, resistance to AGs is an increasing problem. The most common mechanism of resistance to AGs is the presence of AG-modifying enzymes (AMEs) in bacterial cells, with AG acetyltransferases (AACs) being the most prevalent. Recently, it was discovered that Zn2+ metal ions displayed an inhibitory effect on the resistance enzyme AAC(6′)-Ib in Acinetobacter baumannii and Escherichia coli. In this study, we explore a wide array of metal salts (Mg2+, Cr3+, Cr6+, Mn2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, and Au3+ with different counter ions) and their inhibitory effect on a large repertoire of AACs [AAC(2′)-Ic, AAC(3)-Ia, AAC(3)-Ib, AAC(3)-IV, AAC(6′)-Ib′, AAC(6′)-Ie, AAC(6′)-IId, and Eis]. In addition, we determine the MIC values for amikacin and tobramycin in combination with a zinc pyrithione complex in clinical isolates of various bacterial strains (two strains of A. baumannii, three of Enterobacter cloacae, and four of Klebsiella pneumoniae) and one representative of each species purchased from the American Type Culture Collection. PMID:25941215

  8. Molecular identification and functional characterization of the first Nα-acetyltransferase in plastids by global acetylome profiling

    PubMed Central

    Dinh, Trinh V; Bienvenut, Willy V; Linster, Eric; Feldman-Salit, Anna; Jung, Vincent A; Meinnel, Thierry; Hell, Rüdiger; Giglione, Carmela; Wirtz, Markus

    2015-01-01

    Protein Nα-terminal acetylation represents one of the most abundant protein modifications of higher eukaryotes. In humans, six Nα-acetyltransferases (Nats) are responsible for the acetylation of approximately 80% of the cytosolic proteins. N-terminal protein acetylation has not been evidenced in organelles of metazoans, but in higher plants is a widespread modification not only in the cytosol but also in the chloroplast. In this study, we identify and characterize the first organellar-localized Nat in eukaryotes. A primary sequence-based search in Arabidopsis thaliana revealed seven putatively plastid-localized Nats of which AT2G39000 (AtNAA70) showed the highest conservation of the acetyl-CoA binding pocket. The chloroplastic localization of AtNAA70 was demonstrated by transient expression of AtNAA70:YFP in Arabidopsis mesophyll protoplasts. Homology modeling uncovered a significant conservation of tertiary structural elements between human HsNAA50 and AtNAA70. The in vivo acetylation activity of AtNAA70 was demonstrated on a number of distinct protein Nα-termini with a newly established global acetylome profiling test after expression of AtNAA70 in E. coli. AtNAA70 predominately acetylated proteins starting with M, A, S and T, providing an explanation for most protein N-termini acetylation events found in chloroplasts. Like HsNAA50, AtNAA70 displays Nε-acetyltransferase activity on three internal lysine residues. All MS data have been deposited in the ProteomeXchange with identifier PXD001947 (http://proteomecentral.proteomexchange.org/dataset/PXD001947). PMID:25951519

  9. Structures of Wild-Type and Mutant Human Spermidine/Spermine N1-acetyltransferase, a Potential Therapeutic Drug Target

    SciTech Connect

    Bewley,M.; Graziano, V.; Jiang, J.; Matz, E.; Studier, F.; Pegg, A.; Coleman, C.; Flanagan, J.

    2006-01-01

    Spermidine/spermine N{sup 1}-acetyltransferase (SSAT) is a key enzyme in the control of polyamine levels in human cells, as acetylation of spermidine and spermine triggers export or degradation. Increased intracellular polyamine levels accompany several types of cancers as well as other human diseases, and compounds that affect the expression, activity, or stability of SSAT are being explored as potential therapeutic drugs. We have expressed human SSAT from the cloned cDNA in Escherichia coli and have determined high-resolution structures of wild-type and mutant SSAT, as the free dimer and in binary and ternary complexes with CoA, acetyl-CoA (AcCoA), spermine, and the inhibitor N{sup 1},N{sup 11}-bis-(ethyl)-norspermine (BE-3-3-3). These structures show details of binding sites for cofactor, substrates, and inhibitor and provide a framework to understand enzymatic activity, mutations, and the action of potential drugs. Two dimer conformations were observed: a symmetric form with two open surface channels capable of binding substrate or cofactor, and an asymmetric form in which only one of the surface channels appears capable of binding and acetylating polyamines. SSAT was found to self-acetylate lysine-26 in the presence of AcCoA and absence of substrate, a reaction apparently catalyzed by AcCoA bound in the second channel of the asymmetric dimer. These unexpected and intriguing complexities seem likely to have some as yet undefined role in regulating SSAT activity or stability as a part of polyamine homeostasis. Sequence signatures group SSAT with proteins that appear to have thialysine N{sup {var_epsilon}}-acetyltransferase activity.

  10. Doing Being Reprehensive: Some Interactional Features of English as a Lingua Franca in a Chat Room

    ERIC Educational Resources Information Center

    Jenks, Christopher Joseph

    2012-01-01

    Great diversity exists in the way English is being used in the world today. It is now not uncommon to hear a Korean and a Brazilian do business in English, or a Syrian and a Norwegian debating politics in an English-speaking chat room. As opportunities to use English increase and evolve, researchers are left with the difficult challenge of…

  11. Comparing Six Video Chat Tools: A Critical Evaluation by Language Teachers

    ERIC Educational Resources Information Center

    Eroz-Tuga, Betil; Sadler, Randall

    2009-01-01

    This article presents a critical comparison of the usefulness and practicality of six CMC video chat tools (CUworld, ICQ, MSN Messenger, Paltalk, Skype, and Yahoo Messenger) from the perspective of language teaching professionals. This comparison is based on the results of a semester-long project between graduate students at an American university…

  12. Redesigning Chat Forum for Critical Thinking in a Problem-Based Learning Environment

    ERIC Educational Resources Information Center

    Chiang, Akcell Chii-Chung; Fung, Isaac Pak-Wah

    2004-01-01

    Support is needed to promote problem-based learning (PBL) and to enhance critical thinking skills in discussion-based Internet forums. By advancing the capabilities of chat room and forum software, problem-based discussions for learning can be supported further in online learning environments. In this paper, the authors report on MALESAbrain, an…

  13. Negotiation of Meaning and Noticing in Text-Based Online Chat

    ERIC Educational Resources Information Center

    Shekary, M.; Tahririan, M. H.

    2006-01-01

    The aim of this study was to explore the claim that the hybrid nature of synchronic computer-mediated chat (SCMC) promotes the noticing of target language forms, which may, in turn, stimulate the process of second language actuation. When viewed in the context of interaction theory, the hybrid nature of SCMC makes online negotiation a potentially…

  14. Cognitive, Social and Teaching Presence in a Virtual World and a Text Chat

    ERIC Educational Resources Information Center

    Traphagan, Tomoko Watanabe; Chiang, Yueh-hui Vanessa; Chang, Hyeseung Maria; Wattanawaha, Benjaporn; Lee, Haekyung; Mayrath, Michael Charles; Woo, Jeongwon; Yoon, Hyo-Jin; Jee, Min Jung; Resta, Paul E.

    2010-01-01

    Using a framework of cognitive, social, and teaching presence, the nature of learning experiences in a three-dimensional virtual world environment (Second Life) and a text-chat learning environment without visuals (TeachNet) were investigated. A mixed method of code frequencies, coherence graphs, interviews, and a survey was used. The results…

  15. Screening for Autism in Iranian Preschoolers: Contrasting M-CHAT and a Scale Developed in Iran

    ERIC Educational Resources Information Center

    Samadi, Sayyed Ali; McConkey, Roy

    2015-01-01

    Suitable screening instruments for the early diagnosis of autism are not readily available for use with preschoolers in non-Western countries. This study evaluated two tools: M-CHAT which is widely used internationally and one developed in Iran called Hiva. A population sample was recruited of nearly 3000 preschoolers in one Iranian city. Parents…

  16. Inflectional Morphology in Cri du Chat Syndrome--A Case Study

    ERIC Educational Resources Information Center

    Kristoffersen, Kristian Emil

    2012-01-01

    This study examined morphological skills in a girl with cri du chat syndrome, addressing three questions: (1) To what extent does the subject inflect words? (2) To what extent are words inflected correctly? (3) To what extent do the inflected words reflect productive morphological rules, and to what extent can they be considered to be…

  17. Polymorphisms of CHAT but not TFAM or VR22 are Associated with Alzheimer Disease Risk.

    PubMed

    Gao, Lili; Zhang, Yan; Deng, Jinghua; Yu, Wenbing; Yu, Yunxia

    2016-01-01

    BACKGROUND Alzheimer disease (AD) is a chronic neurodegenerative disease that is one of the most prevalent health problems among seniors. The cause of AD has not yet been elucidated, but many risk factors have been identified that might contribute to the pathogenesis and prognosis of AD. We conducted a meta-analysis of studies involving CHAT, TFAM, and VR22 polymorphisms and AD susceptibility to further understand the pathogenesis of AD. MATERIAL AND METHODS PubMed/Medline, Embase, Web of Science, the Cochrane Library, and Google Scholar were searched for relevant articles. Rs1880676, rs2177369, rs3810950, and rs868750 of CHAT; rs1937 and rs2306604 of TFAM; and rs10997691 and rs7070570 of VR22 are studied in this meta-analysis. RESULTS A total of 51 case-control studies with 16 446 cases and 16 057 controls were enrolled. For CHAT, rs2177369 (G>A) in whites and rs3810950 (G>A) in Asians were found to be associated with AD susceptibility. No association was detected between rs1880676 and rs868750 and AD risk. For TFAM and VR22, no significant association was detected in studied single-nucleotide polymorphisms (SNPs). CONCLUSIONS Rs2177369 and rs3810950 of CHAT are associated with AD susceptibility, but rs1880676 and rs868750 are not. Rs1937 and rs2306604 of TFAM, and rs10997691 and rs7070570 of VR22 are not significantly associated with AD risk. PMID:27272392

  18. Researching Contradictions: Cultural Historical Activity Theory Research (CHAT) in the English Classroom

    ERIC Educational Resources Information Center

    Thompson, Ian

    2015-01-01

    This article argues that Cultural Historical Activity Theory (CHAT) is an appropriate theoretical and methodological framework for researchers in English interested in the social contexts of culture and its relationship with the formation of mind and activity in the English classroom. Two key concepts in Vygotsky's thought central to understanding…

  19. Speech and Language Development in Cri Du Chat Syndrome: A Critical Review

    ERIC Educational Resources Information Center

    Kristoffersen, Kristian Emil

    2008-01-01

    This article reviews research on speech and language abilities in people with cri du chat syndrome (CCS). CCS is a rare genetic disorder, with an estimated incidence between 1 in 15,000 and 1 in 50,000 births, resulting from a deletion on the short arm of chromosome 5. In general, individuals have delayed speech and language development, and some…

  20. Grammatical Constructions in Cri du Chat Syndrome--Findings from a Case Study

    ERIC Educational Resources Information Center

    Kristoffersen, Kristian Emil

    2009-01-01

    The literature on grammatical skills in persons with Cri du chat syndrome (CCS) is very limited, and the need for more knowledge in this area is thus evident, in particular for speech and language therapists working with individuals with this syndrome. This case study report describes the syntactic skills of a 14-year-old Norwegian girl with CCS.…

  1. Effects of Interactive Chat versus Independent Writing on L2 Learning

    ERIC Educational Resources Information Center

    Tare, Medha; Golonka, Ewa M.; Vatz, Karen; Bonilla, Carrie L.; Crooks, Carolyn; Strong, Rachel

    2014-01-01

    This study examines the importance of interaction for second language (L2) acquisition by analyzing outcomes from two types of out-of-class activities. The study compared: (a) interactive homework, completed via text chat, and (b) individual homework, completed via independent writing. In a between-subjects design, participants in two…

  2. Combining IM and Vendor-Based Chat: A Report from the Frontlines of an Integrated Service

    ERIC Educational Resources Information Center

    Ward, David; Kern, M. Kathleen

    2006-01-01

    Driven by studies showing that Millennials (ages 18-24) have adopted IM (instant messaging) as a standard communications medium, many libraries are reaching out to their own patrons in this way. At the same time, some of these libraries have invested thousands of dollars in vendor-based chat reference solutions that provide duplicate…

  3. Chatting in L2 Spanish: Interactivity, Self-Efficacy and Interpersonal Relations

    ERIC Educational Resources Information Center

    Sanchez-Castro, Olga; Mrowa-Hopkins, Colette

    2012-01-01

    This study seeks to examine variations in patterns of interactivity as they are displayed in the ongoing discourse construction of high and low self-efficacy learners of Spanish in the context of computer-mediated-communication. The paper specifically focuses on the analysis of synchronous text chats of six university students of Spanish at…

  4. A Technology User's Bill of Rights: Lessons Learned in Chat Rooms

    ERIC Educational Resources Information Center

    Norton-Meier, Lori A.

    2004-01-01

    For the past five years, the author has spent time talking with, interviewing, interacting with, and investigating language with adolescent females in chat rooms while they engage in synchronous talk. The discussion often centers on their interest in pop culture--music, movies, television, books, games, and anything else that is worthy of…

  5. Sleep in Individuals with Cri du Chat Syndrome: A Comparative Study

    ERIC Educational Resources Information Center

    Maas, A. P. H. M.; Didden, R.; Korzilius, H.; Braam, W.; Smits, M. G.; Curfs, L. M. G.

    2009-01-01

    Background: Sleep problems are common in individuals with intellectual disability. Little is known about sleep in children and adults with Cri du Chat syndrome (CDC). Method: Sleep was investigated in 30 individuals with CDC using a sleep questionnaire. Sleep problems and sleep behaviours in individuals with CDC were compared with individuals with…

  6. Changes in Reference Question Complexity Following the Implementation of a Proactive Chat System: Implications for Practice

    ERIC Educational Resources Information Center

    Maloney, Krisellen; Kemp, Jan H.

    2015-01-01

    There has been longstanding debate about whether the level of complexity of questions received at reference desks and via online chat services requires a librarian's expertise. Continued decreases in the number and complexity of reference questions have all but ended the debate; many academic libraries no longer staff service points with…

  7. What Are Youth Asking about Drugs? A Report of NIDA Drug Facts Chat Day

    ERIC Educational Resources Information Center

    Morton, Cory M.; Hoefinger, Heidi; Linn-Walton, Rebecca; Aikins, Ross; Falkin, Gregory P.

    2015-01-01

    The current study analyzes a sample of questions about drugs asked online by youth who participated in the National Institute on Drug Abuse's (NIDA) "Drug Facts Chat Day." The types of drugs youth asked about were coded into 17 substance categories, and the topics they raised were coded into seven thematic categories. The top five…

  8. Comparing Protest Movements in Chile and California: Interculturality in an Internet Chat Exchange

    ERIC Educational Resources Information Center

    Menard-Warwick, Julia

    2009-01-01

    This paper is based on an analysis of chat transcripts from an English-language telecollaboration project between students at universities in Chile and California. This research found that the richest intercultural interactions involved events that could not have been foreseen: the immigrant rights demonstrations in the USA and the massive student…

  9. Text Chat as a Tool for Referential Questioning in Asperger Syndrome

    ERIC Educational Resources Information Center

    Rajendran, Gnanathusharan; Mitchell, Peter

    2006-01-01

    Purpose: This article reports a study in which referential communication in 11 individuals with Asperger syndrome (AS) and 11 controls was compared between text chat and telephone, using a route-solving task. Method: Participants deduced routes by asking closed questions, and the dependent variables were (a) accuracy in working out the route, (b)…

  10. The Effects of Synchronous CMC on Speaking Proficiency and Anxiety: Text versus Voice Chat

    ERIC Educational Resources Information Center

    Satar, H. Muge; Ozdener, Nesrin

    2008-01-01

    This article reports on a study investigating the use of 2 synchronous computer-mediated communication tools: text and voice chat. The experimental design employed 3 groups (text, voice, and control), each consisting of 30 novice-level secondary school learners of English as a foreign language. Over a 4-week period, the participants in the…

  11. Mobile-Based Chatting for Meaning Negotiation in Foreign Language Learning

    ERIC Educational Resources Information Center

    Castrillo, María Dolores; Martín-Monje, Elena; Bárcena, Elena

    2014-01-01

    This paper analyzes the adequacy of mobile chatting via Whatsapp for the enhancement of a type of spontaneous and colloquial written interaction which has a strong connection with oral discourse. This is part of a research project undertaken with Spanish students of German as a foreign language with a beginner's or quasi-beginner's level. The…

  12. Office Hours as You Like Them: Integrating Real-Time Chats into the Course Media Mix.

    ERIC Educational Resources Information Center

    McKeage, Kim

    2001-01-01

    Reports on one professor's use of integrated synchronous electronic office hours (i.e., a "chat room") with asynchronous course conferencing (i.e., email) in a class on introductory marketing. Describes its uses, limitations, benefits, potential problems, and results from a student survey. (EV)

  13. An Overview of Cultural Historical Activity Theory (CHAT) Use in Classroom Research 2000 to 2009

    ERIC Educational Resources Information Center

    Nussbaumer, Doris

    2012-01-01

    Western educational researchers have eagerly accepted activity theory (AT) also known as cultural historical activity theory (CHAT) to collect and analyze data in rich description of complex situations. As this theory is applicable to a wide variety of disciplines, this review is limited to education and specifically to qualitative studies of…

  14. Interaction, Facilitation, and Deep Learning in Cross-Cultural Chat: A Case Study

    ERIC Educational Resources Information Center

    Osman, Gihan; Herring, Susan C.

    2007-01-01

    This case study evaluates the potential of synchronous chat for deep learning in the context of a distance education program between two universities in different cultural contexts, with a focus on interaction and facilitation. Three rubrics--functional moves, social construction of knowledge, and teaching presence--were applied in a longitudinal…

  15. Connecting Developmental Constructions to the Internet: Identity Presentation and Sexual Exploration in Online Teen Chat Rooms

    ERIC Educational Resources Information Center

    Subrahmanyam, Kaveri; Smahel, David; Greenfield, Patricia

    2006-01-01

    The authors examined the online construction of identity and sexuality in a large sample of conversations from monitored and unmonitored teen chat rooms. More than half of the 583 participants (identified by a distinct screen name) communicated identity information, most frequently gender. In this way, participants compensated for the text-based…

  16. From "Hello" to Higher-Order Thinking: The Effect of Coaching and Feedback on Online Chats

    ERIC Educational Resources Information Center

    Stein, David S.; Wanstreet, Constance E.; Slagle, Paula; Trinko, Lynn A.; Lutz, Michelle

    2013-01-01

    This exploratory study examined the effect of a coaching and feedback intervention in teaching presence and social presence on higher-order thinking in an online community of inquiry. Coaching occurred before each chat, and feedback was provided immediately afterwards. The findings suggest that over time, the frequency of higher-order thinking…

  17. More than "Hello" and "Bye-Bye": Opening and Closing the Online Chats in Mandarin Chinese

    ERIC Educational Resources Information Center

    Zhang, De

    2014-01-01

    Reporting on a descriptive study on the first semester Chinese language learners' openings and closings in online chats with age-peer native speakers of Chinese, this paper demonstrates the great promise that telecollaboration holds for foreign language education, and argues for an increasing role of pragmatics in Chinese language…

  18. A Comparison of Chat Room Productivity: In-Class versus Out-of-Class

    ERIC Educational Resources Information Center

    Sanders, Robert

    2006-01-01

    Language production of Spanish students using synchronous CMC (chat) during class time was compared with that of students meeting outside of class. The study included about 100 participants enrolled in 10 sections of a first-quarter Spanish course at a US university. Students in the control group spent 30 minutes of their weekly class time in…

  19. Managing Mutual Orientation in the Absence of Physical Copresence: Multiparty Voice-Based Chat Room Interaction

    ERIC Educational Resources Information Center

    Jenks, Christopher Joseph; Brandt, Adam

    2013-01-01

    This study investigates the interactional work involved in ratifying mutual participation in online, multiparty, voice-based chat rooms. The purpose of this article is to provide a preliminary sketch of how talk and participation is managed in a spoken communication environment that comprises interactants who are not physically copresent but are…

  20. Outcomes of Chat and Discussion Board Use in Online Learning: A Research Synthesis

    ERIC Educational Resources Information Center

    Blackmon, Stephanie J.

    2012-01-01

    Online discussion boards are often used in traditional courses, hybrid courses, and fully online courses. Online chats and discussions can be particularly useful in fully online courses, as these communication connections are often students' only means of connecting with each other and sharing ideas in an open forum. While traditional face-to-face…

  1. Reenergising Professional Creativity from a CHAT Perspective: Seeing Knowledge and History in Practice

    ERIC Educational Resources Information Center

    Ellis, Viv

    2011-01-01

    This article offers a critical examination of aspects of a practice- and theory-developing intervention in the teacher education setting in England designed as a variation of Developmental Work Research. A positive case is argued for the distinctiveness of such cultural-historical activity theory (CHAT-) informed interventions and some points of…

  2. Pilot Susan L. Still chats with white room closeout crew member

    NASA Technical Reports Server (NTRS)

    1997-01-01

    KENNEDY SPACE CENTER, FLA. -- STS-83 Pilot Susan L. Still chats with white room closeout crew member Rene Arriens as she prepares to enter the Space Shuttle Columbia at Launch Pad 39A with assistance from closeout crew worker Bob Saulnier (behind Still).

  3. Polymorphisms of CHAT but not TFAM or VR22 are Associated with Alzheimer Disease Risk

    PubMed Central

    Gao, Lili; Zhang, Yan; Deng, Jinghua; Yu, Wenbing; Yu, Yunxia

    2016-01-01

    Background Alzheimer disease (AD) is a chronic neurodegenerative disease that is one of the most prevalent health problems among seniors. The cause of AD has not yet been elucidated, but many risk factors have been identified that might contribute to the pathogenesis and prognosis of AD. We conducted a meta-analysis of studies involving CHAT, TFAM, and VR22 polymorphisms and AD susceptibility to further understand the pathogenesis of AD. Material/Methods PubMed/Medline, Embase, Web of Science, the Cochrane Library, and Google Scholar were searched for relevant articles. Rs1880676, rs2177369, rs3810950, and rs868750 of CHAT; rs1937 and rs2306604 of TFAM; and rs10997691 and rs7070570 of VR22 are studied in this meta-analysis. Results A total of 51 case-control studies with 16 446 cases and 16 057 controls were enrolled. For CHAT, rs2177369 (G>A) in whites and rs3810950 (G>A) in Asians were found to be associated with AD susceptibility. No association was detected between rs1880676 and rs868750 and AD risk. For TFAM and VR22, no significant association was detected in studied single-nucleotide polymorphisms (SNPs). Conclusions Rs2177369 and rs3810950 of CHAT are associated with AD susceptibility, but rs1880676 and rs868750 are not. Rs1937 and rs2306604 of TFAM, and rs10997691 and rs7070570 of VR22 are not significantly associated with AD risk. PMID:27272392

  4. Combining Live Video and Audio Broadcasting, Synchronous Chat, and Asynchronous Open Forum Discussions in Distance Education

    ERIC Educational Resources Information Center

    Teng, Tian-Lih; Taveras, Marypat

    2004-01-01

    This article outlines the evolution of a unique distance education program that began as a hybrid--combining face-to-face instruction with asynchronous online teaching--and evolved to become an innovative combination of synchronous education using live streaming video, audio, and chat over the Internet, blended with asynchronous online discussions…

  5. Intercomprehension between Romance Languages and the Role of English: A Study of Multilingual Chat Rooms

    ERIC Educational Resources Information Center

    Melo-Pfeifer, Sílvia

    2014-01-01

    In this article, we focus on the role English plays in multilingual chat rooms in Romance Languages. We intend to demonstrate how English, even as forbidden language in this particular setting, is a mediation and a remediation tool. Our conclusions point out that: (1) English is an constructive resource in multilingual communication; (2) it has a…

  6. Collaborative Learning through Chat Discussions and Argument Diagrams in Secondary School

    ERIC Educational Resources Information Center

    Marttunen, Miika; Laurinen, Leena

    2007-01-01

    This study clarifies whether secondary school students develop their argumentation skills through reading and collaboration. The students first constructed an individual argument diagram on genetically modified organisms, read three articles, and improved their diagrams. Next, they engaged in a chat debate, reflected on their debate by…

  7. Prevalence of Autism Spectrum Phenomenology in Cornelia de Lange and Cri du Chat Syndromes

    ERIC Educational Resources Information Center

    Moss, Joanna F.; Oliver, Chris; Berg, Katy; Kaur, Gurmeash; Jephcott, Lesley; Cornish, Kim

    2008-01-01

    Autism spectrum disorder characteristics have not been evaluated in Cornelia de Lange and Cri du Chat syndromes using robust assessments. The Autism Diagnostic Observation Schedule and Social Communication Questionnaire were administered to 34 participants with Cornelia de Lange syndrome and a comparison group of 23 participants with Cri du Chat…

  8. Alert: the dark side of chats--internet without boundaries.

    PubMed

    Aderet, Avshalom

    2009-01-01

    The web has some unique advantages: It eliminates barriers of space and time; information flows quicker and is more accessible to all; the markets are more effective; community and interpersonal communication is more evolved. However, the web is also anonymous, without supervision, freedom of speech is exploited, minors and other web users are exploited, racism and prejudice are encouraged. These manifestations of violence not only hurt many people but actually pose a threat to the existence of the web as a place for exchanging ideas and thoughts, as a tool for relaying messages in a liberal and democratic fashion. Today, it is not legally possible to stop any discussion group or chats, like the one in which Eran participated, which develop dialogues regarding death or suicide. A wise and proper use of the web will be achieved by agreements and not enforcement. It is a process of education in its widest meaning that will be accomplished through the acceptance of norms. Proper use of the web will be possible when all sides--users, site owners and suppliers--willingly commit to values of mutual respect, decency and protection of individual fundamental rights to freedom. The web, which is a great blessing to the communication between people, organizations and cultures, carries with it substantial risks, especially to young users. The rapid expansion of the web and the increase in the number of users has brought many social-ideological dangers alongside the many advantages. In order to deal with these issues, a few years ago I initiated an association known as Eshnav (www.eshnav.org.il) which acts to increase public awareness to the risks and dangers of the web. Eshnav's mission, established to commemorate Eran's memory, is to promote public awareness to the positive and negative aspects of using the web on society and its values, and to promote the wise and safe use of the web. Eran was in great distress and needed empathy, encouragement and support. Sadly, when his

  9. Generation patterns of four groups of cholinergic neurons in rat cervical spinal cord: a combined tritiated thymidine autoradiographic and choline acetyltransferase immunocytochemical study

    SciTech Connect

    Phelps, P.E.; Barber, R.P.; Vaughn, J.E.

    1988-07-22

    This report examines the generation of cholinergic neurons in the spinal cord in order to determine whether the transmitter phenotype of neurons is associated with specific patterns of neurogenesis. Previous immunocytochemical studies identified four groups of choline acetyltransferase (ChAT)-positive neurons in the cervical enlargement of the rat spinal cord. These cell groups vary in both somatic size and location along the previously described ventrodorsal neurogenic gradient of the spinal cord. Thus, large (and small) motoneurons are located in the ventral horn, medium-sized partition cells are found in the intermediate gray matter, small central canal cluster cells are situated within lamina X, and small dorsal horn neurons are scattered predominantly through laminae III-V. The relationships among the birthdays of these four subsets of cholinergic neurons have been examined by combining 3H-thymidine autoradiography and ChAT immunocytochemistry. Embryonic day 11 was the earliest time that neurons were generated within the cervical enlargement. Large and small ChAT-positive motoneurons were produced on E11 and 12, with 70% of both groups being born on E11. ChAT-positive partition cells were produced between E11 and 13, with their peak generation occurring on E12. Approximately 70% of the cholinergic central canal cluster and dorsal horn cells were born on E13, and the remainder of each of these groups was generated on E14. Other investigators have shown that all neurons within the rat cervical spinal cord are produced in a ventrodorsal sequence between E11 and E16. In contrast, ChAT-positive neurons are born only from E11 to E14 and are among the earliest cells generated in the ventral, intermediate, and dorsal subdivisions of the spinal cord.

  10. Measurement of choline acetyltransferase with (/sup 14/C)acetate by a cycling procedure

    SciTech Connect

    O'Neill, J.J.; Hruschak, K.A.

    1987-06-01

    A multiple enzyme and multisubstrate cycling system is described for the radiometric determination of cholineacetyltransferase (ChAT) activity in crude tissue homogenates. The methods employs (/sup 14/C)acetate coupled with the enzymes acetate kinase (AK) and phosphotransacetylase (PTA) for the generation of (/sup 14/C)acetyl CoA. By recycling it was possible to avoid product inhibition of ChAT by CoA, ATP was maintained constant by rephosphorylation of ADP. Kinetics of the individual enzyme reactions were studied and the parameters obtained were used to select appropriate conditions to maintain linearity of varying amounts ChAT activity over a sixty minute time course. The sensitivity of the method is limited only by the specific activity of commercially available isotope labeled acetate.

  11. Isolation of a gene encoding a 1,2-diacylglycerol-sn-acetyl-CoA acetyltransferase from developing seeds of Euonymus alatus.

    PubMed

    Milcamps, Anne; Tumaney, Ajay W; Paddock, Troy; Pan, David A; Ohlrogge, John; Pollard, Mike

    2005-02-18

    1,2-Diacyl-3-acetyl-sn-glycerols (ac-TAG) are unusual triacylglycerols that constitute the major storage lipid in the seeds of Euonymus alatus (Burning Bush). These ac-TAGs have long-chain acyl groups esterified at both the sn-1 and sn-2 positions of glycerol. Cell-free extracts of developing seeds of E. alatus contain both long-chain acyl-CoA and acetyl-CoA sn-1,2-diacylglycerol acyltransferase (DGAT) activity. We have isolated a gene from developing seeds of Euonymus alatus that shows a very high sequence similarity to the members of the DGAT1 gene family (i.e. related to acyl-CoA:cholesterol acyltransferases). This Euonymus DGAT1 gene, when expressed in wild type yeast, results in a 5-fold enhancement of long-chain triacylglycerol (lc-TAG) accumulation, as well as the appearance of low levels of ac-TAG. Hydrogenated ac-TAG molecular species were identified by gas chromatography-mass spectrometry. Microsomes isolated from this transformed yeast show diacylglycerol:acetyl-CoA acetyltransferase activity, which is about 40-fold higher than that measured in microsomes prepared from yeast transformed with the empty vector or with the Arabidopsis thaliana DGAT1 gene. The specific activity of this microsomal acetyltransferase activity is of the same order of magnitude as the microsomal long-chain DGAT activities measured for yeast lines transformed with the empty vector or either the Arabidopsis or Euonymus DGAT1 genes. Despite this, ac-TAG accumulation in yeast transformed with the Euonymus DGAT1 gene was very low (0.26% of lc-TAG), whereas lc-TAG accumulation was enhanced. Possible reasons for this anomaly are discussed. Expression of the Euonymus DGAT1-like gene in yeast lines where endogenous TAG synthesis has been deleted confirmed that the gene product has both long-chain acyl- and acetyltransferase activity. PMID:15579902

  12. Estimation of volume and mass and of changes in volume and mass of selected chat piles in the Picher mining district, Ottawa County, Oklahoma, 2005-10

    USGS Publications Warehouse

    Smith, S. Jerrod

    2013-01-01

    From the 1890s through the 1970s the Picher mining district in northeastern Ottawa County, Oklahoma, was the site of mining and processing of lead and zinc ore. When mining ceased in about 1979, as much as 165–300 million tons of mine tailings, locally referred to as “chat,” remained in the Picher mining district. Since 1979, some chat piles have been mined for aggregate materials and have decreased in volume and mass. Currently (2013), the land surface in the Picher mining district is covered by thousands of acres of chat, much of which remains on Indian trust land owned by allottees. The Bureau of Indian Affairs manages these allotted lands and oversees the sale and removal of chat from these properties. To help the Bureau of Indian Affairs better manage the sale and removal of chat, the U.S. Geological Survey, in cooperation with the Bureau of Indian Affairs, estimated the 2005 and 2010 volumes and masses of selected chat piles remaining on allotted lands in the Picher mining district. The U.S. Geological Survey also estimated the changes in volume and mass of these chat piles for the period 2005 through 2010. The 2005 and 2010 chat-pile volume and mass estimates were computed for 34 selected chat piles on 16 properties in the study area. All computations of volume and mass were performed on individual chat piles and on groups of chat piles in the same property. The Sooner property had the greatest estimated volume (4.644 million cubic yards) and mass (5.253 ± 0.473 million tons) of chat in 2010. Five of the selected properties (Sooner, Western, Lawyers, Skelton, and St. Joe) contained estimated chat volumes exceeding 1 million cubic yards and estimated chat masses exceeding 1 million tons in 2010. Four of the selected properties (Lucky Bill Humbah, Ta Mee Heh, Bird Dog, and St. Louis No. 6) contained estimated chat volumes of less than 0.1 million cubic yards and estimated chat masses of less than 0.1 million tons in 2010. The total volume of all

  13. Delphinidin, a specific inhibitor of histone acetyltransferase, suppresses inflammatory signaling via prevention of NF-{kappa}B acetylation in fibroblast-like synoviocyte MH7A cells

    SciTech Connect

    Seong, Ah-Reum; Yoo, Jung-Yoon; Choi, KyungChul; Lee, Mee-Hee; Lee, Yoo-Hyun; Lee, Jeongmin; Jun, Woojin; Kim, Sunoh; Yoon, Ho-Geun

    2011-07-08

    Highlights: {yields} Delphinidin is a novel inhibitor of p300/CBP histone acetyltransferase. {yields} Delphinidin prevents the hyperacetylation of p65 by inhibiting the HAT activity of p300/CBP. {yields} Delphinidin efficiently suppresses the expression of inflammatory cytokines in MH7A cells via hypoacetylation of NF-{kappa}B. {yields} Delphinidin inhibits cytokine release in the Jurkat T lymphocyte cell line. -- Abstract: Histone acetyltransferase (HAT) inhibitors (HATi) isolated from dietary compounds have been shown to suppress inflammatory signaling, which contributes to rheumatoid arthritis. Here, we identified a novel HATi in Punica granatum L. known as delphinidin (DP). DP did not affect the activity of other epigenetic enzymes (histone deacetylase, histone methyltransferase, or sirtuin1). DP specifically inhibited the HAT activities of p300/CBP. It also inhibited p65 acetylation in MH7A cells, a human rheumatoid arthritis synovial cell line. DP-induced hypoacetylation was accompanied by cytosolic accumulation of p65 and nuclear localization of IKB{alpha}. Accordingly, DP treatment inhibited TNF{alpha}-stimulated increases in NF-{kappa}B function and expression of NF-{kappa}B target genes in these cells. Importantly, DP suppressed lipopolysaccharide-induced pro-inflammatory cytokine expression in Jurkat T lymphocytes, demonstrating that HATi efficiently suppresses cytokine-mediated immune responses. Together, these results show that the HATi activity of DP counters anti-inflammatory signaling by blocking p65 acetylation and that this compound may be useful in preventing inflammatory arthritis.

  14. Histone acetyltransferase p300 mediates histone acetylation of PS1 and BACE1 in a cellular model of Alzheimer's disease.

    PubMed

    Lu, Xi; Deng, Yushuang; Yu, Daohai; Cao, Huiming; Wang, Li; Liu, Li; Yu, Caijia; Zhang, Yuping; Guo, Xiuming; Yu, Gang

    2014-01-01

    Epigenetic modifications, particularly histone acetylation, have been implicated in Alzheimer's disease (AD). While previous studies have suggested that histone hypoacetylation may regulate the expression of genes associated with memory and learning in AD, little is known about histone regulation of AD-related genes such as Presenilin 1(PS1) and beta-site amyloid precursor protein cleaving enzyme 1(BACE1). By utilizing neuroblastoma N2a cells transfected with Swedish mutated human amyloid precursor protein (APP) (N2a/APPswe) and wild-type APP (N2a/APPwt) as cellular models of AD, we examined the alterations of histone acetylation at the promoter regions of PS1 and BACE1 in these cells. Our results revealed that histone H3 acetylation in PS1 and BACE1 promoters is markedly increased in N2a/APPswe cells when compared to N2a/APPwt cells and control cells (vector-transfected), respectively, causing the elevated expression of PS1 and BACE1. In addition, expression of histone acetyltransferase (HAT) adenoviral E1A-associated 300-kDa protein (p300) is dramatically enhanced in N2a/APPswe cells compared to N2a/APPwt and control cells. We have further demonstrated the direct binding of p300 protein to the PS1 and BACE1 promoters in N2a/APPswe cells. The expression levels of H3 acetylation of the PS1 and BACE1 promoters and p300 protein, however, were found to be not significantly different in N2a/APPwt cells when compared to controls in our studies. Furthermore, curcumin, a natural selective inhibitor of p300 in HATs, significantly suppressed the expression of PS1 and BACE1 through inhibition of H3 acetylation in their promoter regions in N2a/APPswe cells. These findings indicated that histone acetyltransferase p300 plays a critical role in controlling the expression of AD-related genes through regulating the acetylation of their promoter regions, suggesting that p300 may represent a novel potential therapeutic target for AD. PMID:25051175

  15. An Acetyltransferase Conferring Tolerance to Toxic Aromatic Amine Chemicals

    PubMed Central

    Martins, Marta; Rodrigues-Lima, Fernando; Dairou, Julien; Lamouri, Aazdine; Malagnac, Fabienne; Silar, Philippe; Dupret, Jean-Marie

    2009-01-01

    Aromatic amines (AA) are a major class of environmental pollutants that have been shown to have genotoxic and cytotoxic potentials toward most living organisms. Fungi are able to tolerate a diverse range of chemical compounds including certain AA and have long been used as models to understand general biological processes. Deciphering the mechanisms underlying this tolerance may improve our understanding of the adaptation of organisms to stressful environments and pave the way for novel pharmaceutical and/or biotechnological applications. We have identified and characterized two arylamine N-acetyltransferase (NAT) enzymes (PaNAT1 and PaNAT2) from the model fungus Podospora anserina that acetylate a wide range of AA. Targeted gene disruption experiments revealed that PaNAT2 was required for the growth and survival of the fungus in the presence of toxic AA. Functional studies using the knock-out strains and chemically acetylated AA indicated that tolerance of P. anserina to toxic AA was due to the N-acetylation of these chemicals by PaNAT2. Moreover, we provide proof-of-concept remediation experiments where P. anserina, through its PaNAT2 enzyme, is able to detoxify the highly toxic pesticide residue 3,4-dichloroaniline in experimentally contaminated soil samples. Overall, our data show that a single xenobiotic-metabolizing enzyme can mediate tolerance to a major class of pollutants in a eukaryotic species. These findings expand the understanding of the role of xenobiotic-metabolizing enzyme and in particular of NATs in the adaptation of organisms to their chemical environment and provide a basis for new systems for the bioremediation of contaminated soils. PMID:19416981

  16. Structural Studies on a Glucosamine/Glucosaminide N-Acetyltransferase.

    PubMed

    Dopkins, Brandon J; Tipton, Peter A; Thoden, James B; Holden, Hazel M

    2016-08-16

    Glucosamine/glucosaminide N-acetyltransferase or GlmA catalyzes the transfer of an acetyl group from acetyl CoA to the primary amino group of glucosamine. The enzyme from Clostridium acetobutylicum is thought to be involved in cell wall rescue. In addition to glucosamine, GlmA has been shown to function on di- and trisaccharides of glucosamine as well. Here we present a structural and kinetic analysis of the enzyme. For this investigation, eight structures were determined to resolutions of 2.0 Å or better. The overall three-dimensional fold of GlmA places it into the tandem GNAT superfamily. Each subunit of the dimer folds into two distinct domains which exhibit high three-dimensional structural similarity. Whereas both domains bind acetyl CoA, it is the C-terminal domain that is catalytically competent. On the basis of the various structures determined in this investigation, two amino acid residues were targeted for further study: Asp 287 and Tyr 297. Although their positions in the active site suggested that they may play key roles in catalysis by functioning as active site bases and acids, respectively, this was not borne out by characterization of the D287N and Y297F variants. The kinetic properties revealed that both residues were important for substrate binding but had no critical roles as acid/base catalysts. Kinetic analyses also indicated that GlmA follows an ordered mechanism with acetyl CoA binding first followed by glucosamine. The product N-acetylglucosamine is then released prior to CoA. The investigation described herein provides significantly new information on enzymes belonging to the tandem GNAT superfamily. PMID:27348258

  17. Polymorphisms of human N-acetyltransferases and cancer risk.

    PubMed

    Agúndez, José A G

    2008-07-01

    Human arylamine N-acetyltransferases (CoASAc; NAT, EC 2.3.1.5) NAT1 and NAT2 play a key role in the metabolism of drugs and environmental chemicals and in the metabolic activation and detoxification of procarcinogens. Phenotyping analyses have revealed an association between NAT enzyme activities and the risk of developing several forms of cancer. As genotyping procedures have become available for NAT1 and NAT2 gene variations, hundreds of association studies on NAT polymorphisms and cancer risk have been conducted. Here we review the findings obtained from these studies. Evidence for a putative association of NAT1 polymorphism and myeloma, lung and bladder cancer, as well as association of NAT2 polymorphisms with non-Hodgkin lymphoma, liver, colorectal and bladder cancer have been reported. In contrast, no consistent evidence for a relevant association of NAT polymorphisms with brain, head & neck, breast, gastric, pancreatic or prostate cancer have been described. Although preliminary data are available, further well-powered studies are required to fully elucidate the role of NAT1 in most human cancers, and that of NAT2 in astrocytoma, meningioma, esophageal, renal, cervical and testicular cancers, as well as in leukaemia and myeloma. This review discusses controversial findings on cancer risk and putative causes of heterogeneity in the proposed associations, and it identifies topics that require further investigation, particularly mechanisms underlying association of NAT polymorphisms and risk for subsets of cancer patients with specific exposures, putative epistatic contribution of polymorphism for other xenobiotic-metabolising enzymes such as glutathione S-transferases of Cytochrome P450 enzymes, and genetic plus environmental interaction. PMID:18680472

  18. The Candida albicans Histone Acetyltransferase Hat1 Regulates Stress Resistance and Virulence via Distinct Chromatin Assembly Pathways

    PubMed Central

    Tscherner, Michael; Zwolanek, Florian; Jenull, Sabrina; Sedlazeck, Fritz J.; Petryshyn, Andriy; Frohner, Ingrid E.; Mavrianos, John; Chauhan, Neeraj; von Haeseler, Arndt; Kuchler, Karl

    2015-01-01

    Human fungal pathogens like Candida albicans respond to host immune surveillance by rapidly adapting their transcriptional programs. Chromatin assembly factors are involved in the regulation of stress genes by modulating the histone density at these loci. Here, we report a novel role for the chromatin assembly-associated histone acetyltransferase complex NuB4 in regulating oxidative stress resistance, antifungal drug tolerance and virulence in C. albicans. Strikingly, depletion of the NuB4 catalytic subunit, the histone acetyltransferase Hat1, markedly increases resistance to oxidative stress and tolerance to azole antifungals. Hydrogen peroxide resistance in cells lacking Hat1 results from higher induction rates of oxidative stress gene expression, accompanied by reduced histone density as well as subsequent increased RNA polymerase recruitment. Furthermore, hat1Δ/Δ cells, despite showing growth defects in vitro, display reduced susceptibility to reactive oxygen-mediated killing by innate immune cells. Thus, clearance from infected mice is delayed although cells lacking Hat1 are severely compromised in killing the host. Interestingly, increased oxidative stress resistance and azole tolerance are phenocopied by the loss of histone chaperone complexes CAF-1 and HIR, respectively, suggesting a central role for NuB4 in the delivery of histones destined for chromatin assembly via distinct pathways. Remarkably, the oxidative stress phenotype of hat1Δ/Δ cells is a species-specific trait only found in C. albicans and members of the CTG clade. The reduced azole susceptibility appears to be conserved in a wider range of fungi. Thus, our work demonstrates how highly conserved chromatin assembly pathways can acquire new functions in pathogenic fungi during coevolution with the host. PMID:26473952

  19. Characterization of a Trypanosoma cruzi acetyltransferase: cellular location, activity and structure.

    PubMed

    Ochaya, Stephen; Respuela, Patricia; Simonsson, Maria; Saraswathi, Abhiman; Branche, Carole; Lee, Jennifer; Búa, Jacqueline; Nilsson, Daniel; Aslund, Lena; Bontempi, Esteban J; Andersson, Björn

    2007-04-01

    Trypanosomatids are widespread parasites that cause three major tropical diseases. In trypanosomatids, as in most other organisms, acetylation is a common protein modification that is important in multiple, diverse processes. This paper describes a new member of the Trypanosoma cruzi acetyltransferase family. The gene is single copy and orthologs are also present in the other two sequenced trypanosomatids, Trypanosoma brucei and Leishmania major. This protein (TcAT-1) has the essential motifs present in members of the GCN5-related acetyltransferase (GNAT) family, as well as an additional motif also found in some enzymes from plant and animal species. The protein is evolutionarily more closely related to this group of enzymes than to histone acetyltransferases. The native protein has a cytosolic cellular location and is present in all three life-cycle stages of the parasite. The recombinant protein was shown to have autoacetylation enzymatic activity. PMID:17270289

  20. Immunity status of adults and children against poliomyelitis virus type 1 strains CHAT and Sabin (LSc-2ab) in Germany

    PubMed Central

    2010-01-01

    Background In October 2007, the working group CEN/TC 216 of the European Committee for standardisation suggested that the Sabin oral poliovirus vaccine type 1 strain (LSc-2ab) presently used for virucidal tests should be replaced by another attenuated vaccine poliovirus type 1 strain, CHAT. Both strains were historically used as oral vaccines, but the Sabin type 1 strain was acknowledged to be more attenuated. In Germany, vaccination against poliomyelitis was introduced in 1962 using the oral polio vaccine (OPV) containing Sabin strain LSc-2ab. The vaccination schedule was changed from OPV to an inactivated polio vaccine (IPV) containing wild polio virus type 1 strain Mahoney in 1998. In the present study, we assessed potential differences in neutralising antibody titres to Sabin and CHAT in persons with a history of either OPV, IPV, or OPV with IPV booster. Methods Neutralisation poliovirus antibodies against CHAT and Sabin 1 were measured in sera of 41 adults vaccinated with OPV. Additionally, sera from 28 children less than 10 years of age and immunised with IPV only were analysed. The neutralisation assay against poliovirus was performed according to WHO guidelines. Results The neutralisation activity against CHAT in adults with OPV vaccination history was significantly lower than against Sabin poliovirus type 1 strains (Wilcoxon signed-rank test P < 0.025). In eight sera, the antibody titres measured against CHAT were less than 8, although the titre against Sabin 1 varied between 8 and 64. Following IPV booster, anti-CHAT antibodies increased rapidly in sera of CHAT-negative adults with OPV history. Sera from children with IPV history neutralised CHAT and Sabin 1 strains equally. Conclusion The lack of neutralising antibodies against the CHAT strain in persons vaccinated with OPV might be associated with an increased risk of reinfection with the CHAT polio virus type 1, and this implies a putative risk of transmission of the virus to polio-free communities. We

  1. A Novel Assay Platform for the Detection of Translation Modulators of Spermidine/Spermine Acetyltransferase

    PubMed Central

    Perez-Leal, Oscar; Abou-Gharbia, Magid; Gordon, John; Childers, Wayne E.; Merali, Salim

    2013-01-01

    Spermidine/spermine-N1-acetyltransferase (SSAT) is a mitochondrial-localized enzyme that is highly inducible and tightly controlled and is the rate-limiting enzyme in polyamine catabolism. It is known that SSAT is induced when polyamine level increases. Although multiple mechanisms have been implicated, translational control is thought to be paramount. Previous studies with transgenic and knockout mice suggested that for certain human conditions, the modulation of SSAT levels could offer therapeutic benefits. Besides polyamines and their analogs, certain stimuli can increase SSAT levels, suggesting that the development of reporters for high throughput screening can lead to the identification of novel pharmacophores that can modulate SSAT translation. Here we report the development and validation of a luciferase-based biosensor system for the identification of compounds that are able to either promote or prevent the translation of SSAT. The system uses HEK293T cells transfected with a construct composed of SSAT mRNA modified to lack upstream open reading frame (uORF) function, is mutated to reduce translational repression and is linked with luciferase. As a proof of principle of the utility of the SSAT translation sensor, we screened the Prestwick drug library (1,200 FDA Approved compounds). The library contained 14 compounds that activated SSAT translation by at least 40% more than the basal expression, but none exceeded the positive control N1, N11-diethylnorspermine. On the other hand, 38 compounds were found to strongly inhibit SSAT translation. We conclude that this biosensor can lead to the identification of novel pharmacophores that are able to modulate the translation of SSAT. PMID:23701549

  2. Degradation of Serotonin N-Acetyltransferase, a Circadian Regulator, by the N-end Rule Pathway.

    PubMed

    Wadas, Brandon; Borjigin, Jimo; Huang, Zheping; Oh, Jang-Hyun; Hwang, Cheol-Sang; Varshavsky, Alexander

    2016-08-12

    Serotonin N-acetyltransferase (AANAT) converts serotonin to N-acetylserotonin (NAS), a distinct biological regulator and the immediate precursor of melatonin, a circulating hormone that influences circadian processes, including sleep. N-terminal sequences of AANAT enzymes vary among vertebrates. Mechanisms that regulate the levels of AANAT are incompletely understood. Previous findings were consistent with the possibility that AANAT may be controlled through its degradation by the N-end rule pathway. By expressing the rat and human AANATs and their mutants not only in mammalian cells but also in the yeast Saccharomyces cerevisiae, and by taking advantage of yeast genetics, we show here that two "complementary" forms of rat AANAT are targeted for degradation by two "complementary" branches of the N-end rule pathway. Specifically, the N(α)-terminally acetylated (Nt-acetylated) Ac-AANAT is destroyed through the recognition of its Nt-acetylated N-terminal Met residue by the Ac/N-end rule pathway, whereas the non-Nt-acetylated AANAT is targeted by the Arg/N-end rule pathway, which recognizes the unacetylated N-terminal Met-Leu sequence of rat AANAT. We also show, by constructing lysine-to-arginine mutants of rat AANAT, that its degradation is mediated by polyubiquitylation of its Lys residue(s). Human AANAT, whose N-terminal sequence differs from that of rodent AANATs, is longer-lived than its rat counterpart and appears to be refractory to degradation by the N-end rule pathway. Together, these and related results indicate both a major involvement of the N-end rule pathway in the control of rodent AANATs and substantial differences in the regulation of rodent and human AANATs that stem from differences in their N-terminal sequences. PMID:27339900

  3. Arylamine N-acetyltransferases: from drug metabolism and pharmacogenetics to drug discovery.

    PubMed

    Sim, E; Abuhammad, A; Ryan, A

    2014-06-01

    Arylamine N-acetyltransferases (NATs) are polymorphic drug-metabolizing enzymes, acetylating arylamine carcinogens and drugs including hydralazine and sulphonamides. The slow NAT phenotype increases susceptibility to hydralazine and isoniazid toxicity and to occupational bladder cancer. The two polymorphic human NAT loci show linkage disequilibrium. All mammalian Nat genes have an intronless open reading frame and non-coding exons. The human gene products NAT1 and NAT2 have distinct substrate specificities: NAT2 acetylates hydralazine and human NAT1 acetylates p-aminosalicylate (p-AS) and the folate catabolite para-aminobenzoylglutamate (p-abaglu). Human NAT2 is mainly in liver and gut. Human NAT1 and its murine homologue are in many adult tissues and in early embryos. Human NAT1 is strongly expressed in oestrogen receptor-positive breast cancer and may contribute to folate and acetyl CoA homeostasis. NAT enzymes act through a catalytic triad of Cys, His and Asp with the architecture of the active site-modulating specificity. Polymorphisms may cause unfolded protein. The C-terminus helps bind acetyl CoA and differs among NATs including prokaryotic homologues. NAT in Salmonella typhimurium supports carcinogen activation and NAT in mycobacteria metabolizes isoniazid with polymorphism a minor factor in isoniazid resistance. Importantly, nat is in a gene cluster essential for Mycobacterium tuberculosis survival inside macrophages. NAT inhibitors are a starting point for novel anti-tuberculosis drugs. Human NAT1-specific inhibitors may act in biomarker detection in breast cancer and in cancer therapy. NAT inhibitors for co-administration with 5-aminosalicylate (5-AS) in inflammatory bowel disease has prompted ongoing investigations of azoreductases in gut bacteria which release 5-AS from prodrugs including balsalazide. PMID:24467436

  4. Arylamine N-acetyltransferases: from drug metabolism and pharmacogenetics to drug discovery

    PubMed Central

    Sim, E; Abuhammad, A; Ryan, A

    2014-01-01

    Arylamine N-acetyltransferases (NATs) are polymorphic drug-metabolizing enzymes, acetylating arylamine carcinogens and drugs including hydralazine and sulphonamides. The slow NAT phenotype increases susceptibility to hydralazine and isoniazid toxicity and to occupational bladder cancer. The two polymorphic human NAT loci show linkage disequilibrium. All mammalian Nat genes have an intronless open reading frame and non-coding exons. The human gene products NAT1 and NAT2 have distinct substrate specificities: NAT2 acetylates hydralazine and human NAT1 acetylates p-aminosalicylate (p-AS) and the folate catabolite para-aminobenzoylglutamate (p-abaglu). Human NAT2 is mainly in liver and gut. Human NAT1 and its murine homologue are in many adult tissues and in early embryos. Human NAT1 is strongly expressed in oestrogen receptor-positive breast cancer and may contribute to folate and acetyl CoA homeostasis. NAT enzymes act through a catalytic triad of Cys, His and Asp with the architecture of the active site-modulating specificity. Polymorphisms may cause unfolded protein. The C-terminus helps bind acetyl CoA and differs among NATs including prokaryotic homologues. NAT in Salmonella typhimurium supports carcinogen activation and NAT in mycobacteria metabolizes isoniazid with polymorphism a minor factor in isoniazid resistance. Importantly, nat is in a gene cluster essential for Mycobacterium tuberculosis survival inside macrophages. NAT inhibitors are a starting point for novel anti-tuberculosis drugs. Human NAT1-specific inhibitors may act in biomarker detection in breast cancer and in cancer therapy. NAT inhibitors for co-administration with 5-aminosalicylate (5-AS) in inflammatory bowel disease has prompted ongoing investigations of azoreductases in gut bacteria which release 5-AS from prodrugs including balsalazide. PMID:24467436

  5. Internet Relay Chat as a Tool in the Autonomous Development of ESL Learners' English Language Ability: An Exploratory Study

    ERIC Educational Resources Information Center

    Coniam, David; Wong, Richard

    2004-01-01

    This pilot study explores the use of Internet Relay Chat facilities such as ICQ in an independent-use mode, as a vehicle for potential English language enhancement. In a small-scale study, a number of Hong Kong secondary school students (Grades 7-10) agreed to participate in an on-line "chatting" programme (in a text-only mode) for a minimum of 20…

  6. Two proteins with ornithine acetyltransferase activity show different functions in Streptomyces clavuligerus: Oat2 modulates clavulanic acid biosynthesis in response to arginine.

    PubMed

    de la Fuente, A; Martín, J F; Rodríguez-García, A; Liras, P

    2004-10-01

    The oat2 gene, located in the clavulanic acid gene cluster in Streptomyces clavuligerus, is similar to argJ, which encodes N-acetylornithine:glutamic acid acetyltransferase activity. Purified proteins obtained by expression in Escherichia coli of the argJ and oat2 genes of S. clavuligerus posses N-acetyltransferase activity. The kinetics and substrate specificities of both proteins are very similar. Deletion of the oat2 gene did not affect the total N-acetylornithine transferase activity and slightly reduced the formation of clavulanic acid under standard culture conditions. However, the oat2 mutant produced more clavulanic acid than the parental strain in cultures supplemented with high levels (above 1 mM) of arginine. The purified S. clavuligerus ArgR protein bound the arginine box in the oat2 promoter, and the expression of oat2 was higher in mutants with a disruption in argR (arginine-deregulated), confirming that the Arg boxes of oat2 are functional in vivo. Our results suggest that the Oat2 protein or one of its reaction products has a regulatory role that modulates clavulanic acid biosynthesis in response to high arginine concentrations. PMID:15375131

  7. Entrainment of the circadian rhythm in the rat pineal N-acetyltransferase activity by prolonged periods of light.

    PubMed

    Illnerová, H; Vanĕcek, J

    1987-08-01

    Entertainment of the circadian rhythm in the pineal N-acetyltranferase activity by prolonged periods of light was studied in rats synchronized with a light:dark regime of 12:12 h by observing phase-shifts in rhythm after delays in switching off the light in the evening or after bringing forward of the morning onset of light. When rats were subjected to delays in switching off the light of up to 10 h and then were released into darkness, phase-delays of the evening N-acetyltransferase rise during the same night corresponded roughly to delays in the light switch off. However, phase-delays of the morning decline were much smaller. After a delay in the evening switch off of 11 h, no N-acetyltransferase rhythm was found in the subsequent darkness. The evening N-acetyltransferase rise was phase-delayed by 6.2 h at most 1 day after delays. Phase-delays of the morning N-acetyltransferase decline were shorter than phase-delays of the N-acetyltransferase rise by only 0.7 h to 0.9 h at most. Hence, 1 day after delays in the evening switch off, the period of the high night N-acetyltransferase activity may be shortened only slightly. The N-acetyltransferase rhythm was abolished only after a 12 h delay in switching off the light. Rats were subjected to a bringing forward of the morning light onset and then were released into darkness 4 h before the usual switch off of light. In the following night, the morning N-acetyltransferase decline, but not the evening rise, was phase advanced considerably. Moreover, when the onset of light was brought forward to before midnight, the N-acetyltransferase rise was even phase-delayed. Hence, 1 day after bringing forward the morning onset of light, the period of the high night N-acetyltransferase activity may be drastically reduced. When rats were subjected to a 4 h light pulse around midnight and then released into darkness, the N-acetyltransferase rhythm in the next night was abolished. The data are discussed in terms of a two

  8. Vers la génération de chats de Schrödinger optiques

    NASA Astrophysics Data System (ADS)

    Ourjoumtsev, A.; Laurat, J.; Tualle-Brouri, R.; Grangier, Ph.

    2006-10-01

    Nous réalisons actuellement une implémentation expérimentale d'un protocole de création de petits chats de Schrödinger optiques. Ces états présentent un fort intérêt dans le domaine de l'information quantique, notamment dans des protocoles de calcul universel ou de métrologie quantique [1,2].

  9. Le syndrome de Cri du Chat : A propos d’une observation

    PubMed Central

    Ouldim, Karim; Samri, Imane; Bouguenouch, Laila; Hamdaoui, Hasna; Otmani, Ihsan El; Hbibi, Mohamed; Chaouki, Sana; Hida, Moustapha

    2012-01-01

    Le syndrome du Cri du Chat (Cri du Chat syndrome, CdCS) est une anomalie chromosomique résultant d’une délétion de taille variable de l’extrémité du bras court du chromosome 5 (5p), incluant une région critique située en p15.2. Il représente une des délétions chromosomiques les plus fréquentes, son incidence dans la population générale est de 1/20 000 à 1/50 000. Les caractéristiques cliniques comprennent un cri monochromatique aigu, une microcéphalie, une dysmorphie cranio-faciale caractéristique évoluant avec l’âge et un retard mental et psychomoteur important. La taille de la délétion est variable, Le traitement est fonction des différents symptômes. Un remaniement chromosomique parental est retrouvé dans 12% des cas et la majorité des délétions responsables de la maladie du cri-du-chat surviennent de novo. Nous présentons une observation d’un syndrome du Cri du Chat, confirmé par caryotype métaphasique (46,XY,del(5)(p13) de novo). A travers cette observation nous mettrons à jour, les actualités scientifiques de ce rare syndrome, ainsi que la place des explorations cytogénétiques dans le diagnostic précis et le conseil génétique des syndromes dysmorphiques. PMID:22368747

  10. STS-79 MISSION SPECIALIST JOHN E. BLAHA AND COMMANDER WILLIAM F. READDY CHAT DURING EMERGENCY EGRESS

    NASA Technical Reports Server (NTRS)

    1996-01-01

    STS-79 Mission Specialist John E. Blaha (left) and Mission Commander William F. Readdy chat during emergency egress training at the 195-foot (59-meter) level of Launch Pad 39A. The training is part of their Terminal Countdown Demonstration Test (TCDT) activities. A dress rehearsal for launch, the TCDT culminates with a simulated countdown. The Space Shuttle Atlantis is undergoing preparations for liftoff on STS-79 no earlier than Sept. 12.

  11. Histone acetyltransferase GCN5 is essential for heat stress-responsive gene activation and thermotolerance in Arabidopsis.

    PubMed

    Hu, Zhaorong; Song, Na; Zheng, Mei; Liu, Xinye; Liu, Zhenshan; Xing, Jiewen; Ma, Junhua; Guo, Weiwei; Yao, Yingyin; Peng, Huiru; Xin, Mingming; Zhou, Dao-Xiu; Ni, Zhongfu; Sun, Qixin

    2015-12-01

    Exposure to temperatures exceeding the normal optimum levels, or heat stress (HS), constitutes an environmental disruption for plants, resulting in severe growth and development retardation. Here we show that loss of function of the Arabidopsis histone acetyltransferase GCN5 results in serious defects in terms of thermotolerance, and considerably impairs the transcriptional activation of HS-responsive genes. Notably, expression of several key regulators such as the HS transcription factors HSFA2 and HSFA3, Multiprotein Bridging Factor 1c (MBF1c) and UV-HYPERSENSITIVE 6 (UVH6) is down-regulated in the gcn5 mutant under HS compared with the wild-type. Chromatin immunoprecipitation (ChIP) assays indicated that GCN5 protein is enriched at the promoter regions of HSFA3 and UVH6 genes, but not in HSFA2 and MBF1c, and that GCN5 facilitates H3K9 and H3K14 acetylation, which are associated with HSFA3 and UVH6 activation under HS. Moreover, constitutive expression of UVH6 in the gcn5 mutant partially restores heat tolerance. Taken together, our data indicate that GCN5 plays a key role in the preservation of thermotolerance via versatile regulation in Arabidopsis. In addition, expression of the wheat TaGCN5 gene re-establishes heat tolerance in Arabidopsis gcn5 mutant plants, suggesting that GCN5-mediated thermotolerance may be conserved between Arabidopsis and wheat. PMID:26576681

  12. Spt-Ada-Gcn5-Acetyltransferase (SAGA) Complex in Plants: Genome Wide Identification, Evolutionary Conservation and Functional Determination

    PubMed Central

    Srivastava, Rakesh; Rai, Krishan Mohan; Pandey, Bindu; Singh, Sudhir P.; Sawant, Samir V.

    2015-01-01

    The recruitment of RNA polymerase II on a promoter is assisted by the assembly of basal transcriptional machinery in eukaryotes. The Spt-Ada-Gcn5-Acetyltransferase (SAGA) complex plays an important role in transcription regulation in eukaryotes. However, even in the advent of genome sequencing of various plants, SAGA complex has been poorly defined for their components and roles in plant development and physiological functions. Computational analysis of Arabidopsis thaliana and Oryza sativa genomes for SAGA complex resulted in the identification of 17 to 18 potential candidates for SAGA subunits. We have further classified the SAGA complex based on the conserved domains. Phylogenetic analysis revealed that the SAGA complex proteins are evolutionary conserved between plants, yeast and mammals. Functional annotation showed that they participate not only in chromatin remodeling and gene regulation, but also in different biological processes, which could be indirect and possibly mediated via the regulation of gene expression. The in silico expression analysis of the SAGA components in Arabidopsis and O. sativa clearly indicates that its components have a distinct expression profile at different developmental stages. The co-expression analysis of the SAGA components suggests that many of these subunits co-express at different developmental stages, during hormonal interaction and in response to stress conditions. Quantitative real-time PCR analysis of SAGA component genes further confirmed their expression in different plant tissues and stresses. The expression of representative salt, heat and light inducible genes were affected in mutant lines of SAGA subunits in Arabidopsis. Altogether, the present study reveals expedient evidences of involvement of the SAGA complex in plant gene regulation and stress responses. PMID:26263547

  13. Argumentation in Secondary School Students' Structured and Unstructured Chat Discussions

    ERIC Educational Resources Information Center

    Salminen, Timo; Marttunen, Miika; Laurinen, Leena

    2012-01-01

    Joint construction of new knowledge demands that persons can express their statements in a convincing way and explore other people's arguments constructively. For this reason, more knowledge on different means to support collaborative argumentation is needed. This study clarifies whether structured interaction supports students' critical and…

  14. Comparative investigation of the xenobiotic metabolizing arylamine N-acetyltransferase enzyme family among fungi

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Arylamine N-acetyltransferases (NATs) are xenobiotic metabolizing enzymes well-characterized in several bacteria and higher eukaryotes. The role of NATs in fungal biology has only recently been investigated. The NAT1 gene of Gibberella moniliformis was the first NAT cloned and characterized from fun...

  15. Structure of soybean serine acetyltransferase and formation of the cysteine regulatory complex as a molecular chaperone

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Serine acetyltransferase (SAT) catalyzes the limiting reaction in plant and microbial biosynthesis of cysteine. In addition to its enzymatic function, SAT forms a macromolecular complex with O-acetylserine sulfhydrylase (OASS). Formation of the cysteine regulatory complex (CRC) is a critical biochem...

  16. AAC(3)-XI, a new aminoglycoside 3-N-acetyltransferase from Corynebacterium striatum.

    PubMed

    Galimand, Marc; Fishovitz, Jennifer; Lambert, Thierry; Barbe, Valérie; Zajicek, Jaroslav; Mobashery, Shahriar; Courvalin, Patrice

    2015-09-01

    Corynebacterium striatum BM4687 was resistant to gentamicin and tobramycin but susceptible to kanamycin A and amikacin, a phenotype distinct among Gram-positive bacteria. Analysis of the entire genome of this strain did not detect any genes for known aminoglycoside resistance enzymes. Yet, annotation of the coding sequences identified 12 putative acetyltransferases or GCN5-related N-acetyltransferases. A total of 11 of these coding sequences were also present in the genomes of other Corynebacterium spp. The 12th coding sequence had 55 to 60% amino acid identity with acetyltransferases in Actinomycetales. The gene was cloned in Escherichia coli, where it conferred resistance to aminoglycosides by acetylation. The protein was purified to homogeneity, and its steady-state kinetic parameters were determined for dibekacin and kanamycin B. The product of the turnover of dibekacin was purified, and its structure was elucidated by high-field nuclear magnetic resonance (NMR), indicating transfer of the acetyl group to the amine at the C-3 position. Due to the unique profile of the reaction, it was designated aminoglycoside 3-N-acetyltransferase type XI. PMID:26149994

  17. Phylogenetic and biological investigation of the xenobiotic metabolizing arylamine N-acetyltransferase enzyme family among fungi

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Arylamine N-acetyltransferases (NATs) are xenobiotic metabolizing enzymes well-characterized in several bacteria and eukaryotic organisms. The role of NATs in fungal biology has only recently been investigated. The NAT1 (FDB2) gene of Fusarium verticillioides was the first NAT cloned and character...

  18. AAC(3)-XI, a New Aminoglycoside 3-N-Acetyltransferase from Corynebacterium striatum

    PubMed Central

    Galimand, Marc; Fishovitz, Jennifer; Lambert, Thierry; Barbe, Valérie; Zajicek, Jaroslav

    2015-01-01

    Corynebacterium striatum BM4687 was resistant to gentamicin and tobramycin but susceptible to kanamycin A and amikacin, a phenotype distinct among Gram-positive bacteria. Analysis of the entire genome of this strain did not detect any genes for known aminoglycoside resistance enzymes. Yet, annotation of the coding sequences identified 12 putative acetyltransferases or GCN5-related N-acetyltransferases. A total of 11 of these coding sequences were also present in the genomes of other Corynebacterium spp. The 12th coding sequence had 55 to 60% amino acid identity with acetyltransferases in Actinomycetales. The gene was cloned in Escherichia coli, where it conferred resistance to aminoglycosides by acetylation. The protein was purified to homogeneity, and its steady-state kinetic parameters were determined for dibekacin and kanamycin B. The product of the turnover of dibekacin was purified, and its structure was elucidated by high-field nuclear magnetic resonance (NMR), indicating transfer of the acetyl group to the amine at the C-3 position. Due to the unique profile of the reaction, it was designated aminoglycoside 3-N-acetyltransferase type XI. PMID:26149994

  19. Genetic Variation at the N-acetyltransferase (NAT) Genes in Global Populations

    EPA Science Inventory

    Functional variability at the N-acetyltransferase (NAT) genes is associated with adverse drug reactions and cancer susceptibility in humans. Previous studies of small sets of ethnic groups have indicated that the NAT genes have high levels of amino acid variation that differ in f...

  20. Optimizing Fracture Treatments in a Mississippian "Chat" Reservoir, South-Central Kansas

    SciTech Connect

    K. David Newell; Saibal Bhattacharya; Alan Byrnes; W. Lynn Watney; Willard Guy

    2005-10-01

    This project is a collaboration of Woolsey Petroleum Corporation (a small independent operator) and the Kansas Geological Survey. The project will investigate geologic and engineering factors critical for designing hydraulic fracture treatments in Mississippian ''chat'' reservoirs. Mississippian reservoirs, including the chat, account for 159 million m3 (1 billion barrels) of the cumulative oil produced in Kansas. Mississippian reservoirs presently represent {approx}40% of the state's 5.6*106m3 (35 million barrels) annual production. Although geographically widespread, the ''chat'' is a heterogeneous reservoir composed of chert, cherty dolomite, and argillaceous limestone. Fractured chert with micro-moldic porosity is the best reservoir in this 18- to 30-m-thick (60- to 100-ft) unit. The chat will be cored in an infill well in the Medicine Lodge North field (417,638 m3 [2,626,858 bbls] oil; 217,811,000 m3 [7,692,010 mcf] gas cumulative production; discovered 1954). The core and modern wireline logs will provide geological and petrophysical data for designing a fracture treatment. Optimum hydraulic fracturing design is poorly defined in the chat, with poor correlation of treatment size to production increase. To establish new geologic and petrophysical guidelines for these treatments, data from core petrophysics, wireline logs, and oil-field maps will be input to a fracture-treatment simulation program. Parameters will be established for optimal size of the treatment and geologic characteristics of the predicted fracturing. The fracturing will be performed and subsequent wellsite tests will ascertain the results for comparison to predictions. A reservoir simulation program will then predict the rate and volumetric increase in production. Comparison of the predicted increase in production with that of reality, and the hypothetical fracturing behavior of the reservoir with that of its actual behavior, will serve as tests of the geologic and petrophysical

  1. Regulation of a Protein Acetyltransferase in Myxococcus xanthus by the Coenzyme NADP+

    PubMed Central

    Liu, Xin-Xin

    2015-01-01

    ABSTRACT NADP+ is a vital cofactor involved in a wide variety of activities, such as redox potential and cell death. Here, we show that NADP+ negatively regulates an acetyltransferase from Myxococcus xanthus, Mxan_3215 (MxKat), at physiologic concentrations. MxKat possesses an NAD(P)-binding domain fused to the Gcn5-type N-acetyltransferase (GNAT) domain. We used isothermal titration calorimetry (ITC) and a coupled enzyme assay to show that NADP+ bound to MxKat and that the binding had strong effects on enzyme activity. The Gly11 residue of MxKat was confirmed to play an important role in NADP+ binding using site-directed mutagenesis and circular dichroism spectrometry. In addition, using mass spectrometry, site-directed mutagenesis, and a coupling enzymatic assay, we demonstrated that MxKat acetylates acetyl coenzyme A (acetyl-CoA) synthetase (Mxan_2570) at Lys622 in response to changes in NADP+ concentration. Collectively, our results uncovered a mechanism of protein acetyltransferase regulation by the coenzyme NADP+ at physiological concentrations, suggesting a novel signaling pathway for the regulation of cellular protein acetylation. IMPORTANCE Microorganisms have developed various protein posttranslational modifications (PTMs), which enable cells to respond quickly to changes in the intracellular and extracellular milieus. This work provides the first biochemical characterization of a protein acetyltransferase (MxKat) that contains a fusion between a GNAT domain and NADP+-binding domain with Rossmann folds, and it demonstrates a novel signaling pathway for regulating cellular protein acetylation in M. xanthus. We found that NADP+ specifically binds to the Rossmann fold of MxKat and negatively regulates its acetyltransferase activity. This finding provides novel insight for connecting cellular metabolic status (NADP+ metabolism) with levels of protein acetylation, and it extends our understanding of the regulatory mechanisms underlying PTMs. PMID:26598367

  2. Epigenetic regulation of proliferation and invasion in hepatocellular carcinoma cells by CBP/p300 histone acetyltransferase activity.

    PubMed

    Inagaki, Yuji; Shiraki, Katsuya; Sugimoto, Kazushi; Yada, Takazumi; Tameda, Masahiko; Ogura, Suguru; Yamamoto, Norihiko; Takei, Yoshiyuki; Ito, Masaaki

    2016-02-01

    Altered epigenetic control of gene expression plays a substantial role in tumor development and progression. Accumulating studies suggest that somatic mutations of CREB binding proteins (CBP)/p300 occur in some cancer cells. CBP/p300 possess histone acetyltransferase (HAT) activity, and are involved in many cellular processes. In this study, we investigated the expression and functional role of CBP/p300 in hepatocellular carcinoma (HCC) using the specific inhibitor C646 of CBP/p300 HAT activity. We examined its effect on several apoptosis-related proteins and invasion-related genes. The results showed that CBP/p300 were highly expressed in HCC tissues and that expression of p300, but not of CBP, was strongly correlated with the malignant character of HCC. C646 inhibited proliferation of HCC cell lines in a dose dependent manner. C646 significantly augmented TRAIL-induced apoptotic sensitivity, which was accompanied by reduced levels of survivin, in HepG2, HLE and SK-HEP1 cells. C646 significantly inhibited invasion of Huh7, HLE and SK-HEP1 cells. The level of matrix metallopeptidase 15 (MMP15) mRNA expression was significantly reduced, whereas the level of laminin alpha 3 (LAMA3) and secreted phosphoprotein 1 (SPP1) mRNA expression was significantly increased in Huh7 cells following exposure to C646. In conclusion, our results suggest that CBP/p300 HAT activity has an important role in malignant transformation, proliferation, apoptotic sensitivity and invasion in HCC. CBP/p300 could be a promising therapeutic target in HCC. PMID:26676548

  3. Cohesin recruits the Esco1 acetyltransferase genome wide to repress transcription and promote cohesion in somatic cells.

    PubMed

    Rahman, Sadia; Jones, Mathew J K; Jallepalli, Prasad V

    2015-09-01

    The cohesin complex links DNA molecules and plays key roles in the organization, expression, repair, and segregation of eukaryotic genomes. In vertebrates the Esco1 and Esco2 acetyltransferases both modify cohesin's Smc3 subunit to establish sister chromatid cohesion during S phase, but differ in their N-terminal domains and expression during development and across the cell cycle. Here we show that Esco1 and Esco2 also differ dramatically in their interaction with chromatin, as Esco1 is recruited by cohesin to over 11,000 sites, whereas Esco2 is infrequently enriched at REST/NRSF target genes. Esco1's colocalization with cohesin occurs throughout the cell cycle and depends on two short motifs (the A-box and B-box) present in and unique to all Esco1 orthologs. Deleting either motif led to the derepression of Esco1-proximal genes and functional uncoupling of cohesion from Smc3 acetylation. In contrast, other mutations that preserved Esco1's recruitment separated its roles in cohesion establishment and gene silencing. We conclude that Esco1 uses cohesin as both a substrate and a scaffold for coordinating multiple chromatin-based transactions in somatic cells. PMID:26305936

  4. Nuclear Arc Interacts with the Histone Acetyltransferase Tip60 to Modify H4K12 Acetylation1,2,3

    PubMed Central

    Wee, Caroline L.; Teo, Shaun; Oey, Nicodemus E.; Wright, Graham D.; VanDongen, Hendrika M.A.

    2014-01-01

    Abstract Arc is an immediate-early gene whose genetic ablation selectively abrogates long-term memory, indicating a critical role in memory consolidation. Although Arc protein is found at synapses, it also localizes to the neuronal nucleus, where its function is less understood. Nuclear Arc forms a complex with the β-spectrin isoform βSpIVΣ5 and associates with PML bodies, sites of epigenetic regulation of gene expression. We report here a novel interaction between Arc and Tip60, a histone-acetyltransferase and subunit of a chromatin-remodelling complex, using biochemistry and super-resolution microscopy in primary rat hippocampal neurons. Arc and βSpIVΣ5 are recruited to nuclear Tip60 speckles, and the three proteins form a tight complex that localizes to nuclear perichromatin regions, sites of transcriptional activity. Neuronal activity-induced expression of Arc (1) increases endogenous nuclear Tip60 puncta, (2) recruits Tip60 to PML bodies, and (3) increases histone acetylation of Tip60 substrate H4K12, a learning-induced chromatin modification. These mechanisms point to an epigenetic role for Arc in regulating memory consolidation. PMID:26464963

  5. Rare allele of a previously unidentified histone H4 acetyltransferase enhances grain weight, yield, and plant biomass in rice

    PubMed Central

    Song, Xian Jun; Kuroha, Takeshi; Ayano, Madoka; Furuta, Tomoyuki; Nagai, Keisuke; Komeda, Norio; Segami, Shuhei; Miura, Kotaro; Ogawa, Daisuke; Kamura, Takumi; Suzuki, Takamasa; Higashiyama, Tetsuya; Yamasaki, Masanori; Mori, Hitoshi; Inukai, Yoshiaki; Wu, Jianzhong; Kitano, Hidemi; Sakakibara, Hitoshi; Jacobsen, Steven E.; Ashikari, Motoyuki

    2015-01-01

    Grain weight is an important crop yield component; however, its underlying regulatory mechanisms are largely unknown. Here, we identify a grain-weight quantitative trait locus (QTL) encoding a new-type GNAT-like protein that harbors intrinsic histone acetyltransferase activity (OsglHAT1). Our genetic and molecular evidences pinpointed the QTL-OsglHAT1’s allelic variations to a 1.2-kb region upstream of the gene body, which is consistent with its function as a positive regulator of the traits. Elevated OsglHAT1 expression enhances grain weight and yield by enlarging spikelet hulls via increasing cell number and accelerating grain filling, and increases global acetylation levels of histone H4. OsglHAT1 localizes to the nucleus, where it likely functions through the regulation of transcription. Despite its positive agronomical effects on grain weight, yield, and plant biomass, the rare allele elevating OsglHAT1 expression has so far escaped human selection. Our findings reveal the first example, to our knowledge, of a QTL for a yield component trait being due to a chromatin modifier that has the potential to improve crop high-yield breeding. PMID:25535376

  6. NAT8L (N-Acetyltransferase 8-Like) Accelerates Lipid Turnover and Increases Energy Expenditure in Brown Adipocytes*

    PubMed Central

    Pessentheiner, Ariane R.; Pelzmann, Helmut J.; Walenta, Evelyn; Schweiger, Martina; Groschner, Lukas N.; Graier, Wolfgang F.; Kolb, Dagmar; Uno, Kyosuke; Miyazaki, Toh; Nitta, Atsumi; Rieder, Dietmar; Prokesch, Andreas; Bogner-Strauss, Juliane G.

    2013-01-01

    NAT8L (N-acetyltransferase 8-like) catalyzes the formation of N-acetylaspartate (NAA) from acetyl-CoA and aspartate. In the brain, NAA delivers the acetate moiety for synthesis of acetyl-CoA that is further used for fatty acid generation. However, its function in other tissues remained elusive. Here, we show for the first time that Nat8l is highly expressed in adipose tissues and murine and human adipogenic cell lines and is localized in the mitochondria of brown adipocytes. Stable overexpression of Nat8l in immortalized brown adipogenic cells strongly increases glucose incorporation into neutral lipids, accompanied by increased lipolysis, indicating an accelerated lipid turnover. Additionally, mitochondrial mass and number as well as oxygen consumption are elevated upon Nat8l overexpression. Concordantly, expression levels of brown marker genes, such as Prdm16, Cidea, Pgc1α, Pparα, and particularly UCP1, are markedly elevated in these cells. Treatment with a PPARα antagonist indicates that the increase in UCP1 expression and oxygen consumption is PPARα-dependent. Nat8l knockdown in brown adipocytes has no impact on cellular triglyceride content, lipogenesis, or oxygen consumption, but lipolysis and brown marker gene expression are increased; the latter is also observed in BAT of Nat8l-KO mice. Interestingly, the expression of ATP-citrate lyase is increased in Nat8l-silenced adipocytes and BAT of Nat8l-KO mice, indicating a compensatory mechanism to sustain the acetyl-CoA pool once Nat8l levels are reduced. Taken together, our data show that Nat8l impacts on the brown adipogenic phenotype and suggests the existence of the NAT8L-driven NAA metabolism as a novel pathway to provide cytosolic acetyl-CoA for lipid synthesis in adipocytes. PMID:24155240

  7. Subfunctionalization of arylalkylamine N-acetyltransferases in the sea bass Dicentrarchus labrax: two-ones for one two.

    PubMed

    Paulin, Charles-Hubert; Cazaméa-Catalan, Damien; Zilberman-Peled, Bina; Herrera-Perez, Patricia; Sauzet, Sandrine; Magnanou, Elodie; Fuentès, Michael; Gothilf, Yoav; Muñoz-Cueto, Jose Antonio; Falcón, Jack; Besseau, Laurence

    2015-10-01

    Melatonin is an important component of the vertebrates circadian system, synthetized from serotonin by the successive action of the arylalkylamine N-acetyltransferase (Aanat: serotonin→N-acetylserotonin) and acetylserotonin-O-methyltransferase (Asmt: N-acetylserotonin→melatonin). Aanat is responsible for the daily rhythm in melatonin production. Teleost fish are unique because they express two Aanat genes, aanat1 and aanat2, mainly expressed in the retina and pineal gland, respectively. In silico analysis indicated that the teleost-specific whole-genome duplication generated Aanat1 duplicates (aanat1a and aanat1b); some fish express both of them, while others express either one of the isoforms. Here, we bring the first information on the structure, function, and distribution of Aanat1a and Aanat1b in a teleost, the sea bass Dicentrarchus labrax. Aanat1a and Aanat1b displayed a wide and distinct distribution in the nervous system and peripheral tissues, while Aanat2 appeared as a pineal enzyme. Co-expression of Aanats with asmt was found in the pineal gland and the three retinal nuclear layers. Enzyme kinetics indicated subtle differences in the affinity and catalytic efficiency of Aanat1a and Aanat1b for indolethylamines and phenylethylamines, respectively. Our data are consistent with the idea that Aanat2 is a pineal enzyme involved in melatonin production, while Aanat1 enzymes have a broader range of functions including melatonin synthesis in the retina, and catabolism of serotonin and dopamine in the retina and other tissues. The data are discussed in light of the recently uncovered roles of N-acetylserotonin and N-acetyldopamine as antioxidants, neuroprotectants, and modulators of cell proliferation and enzyme activities. PMID:26267754

  8. Nickel and cobalt resistance engineered in Escherichia coli by overexpression of serine acetyltransferase from the nickel hyperaccumulator plant Thlaspi goesingense.

    PubMed

    Freeman, John L; Persans, Michael W; Nieman, Ken; Salt, David E

    2005-12-01

    The overexpression of serine acetyltransferase from the Ni-hyperaccumulating plant Thlaspi goesingense causes enhanced nickel and cobalt resistance in Escherichia coli. Furthermore, overexpression of T. goesingense serine acetyltransferase results in enhanced sensitivity to cadmium and has no significant effect on resistance to zinc. Enhanced nickel resistance is directly related to the constitutive overactivation of sulfur assimilation and glutathione biosynthesis, driven by the overproduction of O-acetyl-L-serine, the product of serine acetyltransferase and a positive regulator of the cysteine regulon. Nickel in the serine acetyltransferase-overexpressing strains is not detoxified by coordination or precipitation with sulfur, suggesting that glutathione is involved in reducing the oxidative damage imposed by nickel. PMID:16332856

  9. Nickel and Cobalt Resistance Engineered in Escherichia coli by Overexpression of Serine Acetyltransferase from the Nickel Hyperaccumulator Plant Thlaspi goesingense

    PubMed Central

    Freeman, John L.; Persans, Michael W.; Nieman, Ken; Salt, David E.

    2005-01-01

    The overexpression of serine acetyltransferase from the Ni-hyperaccumulating plant Thlaspi goesingense causes enhanced nickel and cobalt resistance in Escherichia coli. Furthermore, overexpression of T. goesingense serine acetyltransferase results in enhanced sensitivity to cadmium and has no significant effect on resistance to zinc. Enhanced nickel resistance is directly related to the constitutive overactivation of sulfur assimilation and glutathione biosynthesis, driven by the overproduction of O-acetyl-l-serine, the product of serine acetyltransferase and a positive regulator of the cysteine regulon. Nickel in the serine acetyltransferase-overexpressing strains is not detoxified by coordination or precipitation with sulfur, suggesting that glutathione is involved in reducing the oxidative damage imposed by nickel. PMID:16332856

  10. System-wide Studies of N-Lysine Acetylation in Rhodopseudomonas palustris Reveals Substrate Specificity of Protein Acetyltransferases

    SciTech Connect

    Crosby, Heidi A; Pelletier, Dale A; Hurst, Gregory {Greg} B; Escalante-Semerena, Jorge C

    2012-01-01

    Background: Protein acetylation is widespread in prokaryotes. Results: Six new acyl-CoA synthetases whose activities are controlled by acetylation were identified, and their substrate preference established. A new protein acetyltransferase was also identified and its substrate specificity determined. Conclusion: Protein acetyltransferases acetylate a conserved lysine residue in protein substrates. Significance: The R. palustris Pat enzyme specifically acetylates AMP-forming acyl-CoA synthetases and regulates fatty acid metabolism.

  11. Physical mapping in the Cri du Chat region on human chromosome 5

    SciTech Connect

    Church, D.M.; Bengtsson, U.; Niebuhr, E.

    1994-09-01

    The Cri du Chat syndrome is a segmental aneusomy associated with deletions in the short arm of human chromosome 5. More specifically, the cytogenetic band 5p15.2 must be deleted in order to manifest the typical phenotypic signs. We have studied several cell lines from individuals who have chromosomal abnormalities within this cytogenetic band but who do not have typical Cri du Chat syndrome. In fact, several individual studied have no discernible features of this syndrome. Using fluorescent in situ hybridization (FISH) analysis and PCR analysis on somatic cell hybrids we have mapped the breakpoints relative to each other within this band. There is a great degree of phenotypic heterogeneity between several of the patients, even those which share common breakpoints. This heterogeneity makes it very difficult to narrow the region of interest to a very small (<1 Mb) region. In order to more thoroughly analyze this region, we have assembled a yeast artificial chromosome (YAC) contig of part of this region. This contig has been analyzed for STS content and covers approximately a 1.5-2.0 Mb region within 5p15.2. In addition, we have constructed a radiation hybrid map of the region. The YACs contained within the minimal contig have been used as hybridization probes to isolate corresponding cosmid clones within the region of interest. These cosmids, in turn, are being utilized to obtain potential exons using exon amplification. Several cosmids within this region have been isolated by STS content and potential exons have been isolated from them. These exons have been used as probes to isolate cDNA clones from the region. It is our hope that isolation of genes throughout the region of interest will allow a better understanding of the etiology of Cri du Chat.

  12. Effects of human arylamine N-acetyltransferase I knockdown in triple-negative breast cancer cell lines

    PubMed Central

    Tiang, Jacky M; Butcher, Neville J; Minchin, Rodney F

    2015-01-01

    Expression of human arylamine N-acetyltransferase I (NAT1) has been associated with various cancer subtypes and inhibition of this enzyme with small molecule inhibitors or siRNA affects cell growth and survival. Here, we have investigated the role of NAT1 in the invasiveness of breast cancer cells both in vitro and in vivo. We knocked down NAT1 using a lentivirus-based shRNA approach and observed marked changes in cell morphology in the triple-negative breast cancer cell lines MDA-MB-231, MDA-MB-436, and BT-549. Most notable was a reduction in the number and size of the filopodia protrusions on the surface of the cells. The loss of filopodia could be rescued by the reintroduction of NAT1 into the knockdown cells. NAT1 expression was localized to the lamellipodia and extended into the filopodia protrusions. In vitro invasion through Geltrex was significantly inhibited in both the MDA cell lines but not in the BT-549 cells. The expression of Snail increased when NAT1 was knocked down, while other genes associated with mesenchymal to epithelial transition (vimentin, cytokeratin-18, and Twist) did not show any changes. By contrast, both N-cadherin and β-catenin were significantly reduced. When MDA-MB-231 cells expressing shRNA were injected in vivo into BALB/c nu/nu nude mice, a significant reduction in the number of colonies that formed in the lungs was observed. Taken together, the results show that NAT1 can alter the invasion and metastatic properties of some triple-negative breast cancer cells but not all. The study suggests that NAT1 may be a novel therapeutic target in a subset of breast cancers. PMID:25627111

  13. Identification of the satA gene encoding a streptogramin A acetyltransferase in Enterococcus faecium BM4145.

    PubMed Central

    Rende-Fournier, R; Leclercq, R; Galimand, M; Duval, J; Courvalin, P

    1993-01-01

    Enterococcus faecium BM4145, a clinical isolate from urine, was resistant to streptogramin group A antibiotics by inactivation. The strain harbored a plasmid containing a gene, satA, responsible for this resistance; this gene was cloned and sequenced. It encoded SatA, a protein deduced to be 23,634 Da in mass and homologous with a new family of chloramphenicol acetyltransferases described in Agrobacterium tumefaciens, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. The similarity of SatA to other acetyltransferases, LacA (thiogalactoside acetyltransferase) and CysE (serine acetyltransferase) from E. coli, and to two putative acetyltransferases, NodL from Rhizobium leguminosarum and Urf1 from E. coli, was also observed in a region considered to be the enzyme's active site. Acetylation experiments indicated that acetyl coenzyme A was necessary for SatA activity and that a single acetylated derivative of pristinamycin IIA was produced. Other members of the streptogramin A group such as virginiamycin M and RP54476 were also substrates for the enzyme. We conclude that resistance to the streptogramin A group of antibiotics in E. faecium BM4145 is due to acetylation by an enzyme related to the novel chloramphenicol acetyltransferase family. Images PMID:8257133

  14. Real-time reference: the use of chat technology to improve point of need assistance.

    PubMed

    Connor, Elizabeth

    2002-01-01

    Chat reference refers to the use of instant messaging and call center software to support interactive text or voice communication with library patrons. Instant messaging has been integrated into many e-commerce environments, and into the social lives of many teenagers and young adults, affording a level of immediacy and intimacy not possible with e-mail applications. The convergence and interoperability of new and emerging technologies can be used to develop new communities of users that view libraries as being essential to their education, patient care, and research activities. PMID:12659452

  15. IRC on your dime? What you really need to know about Internet relay chat

    SciTech Connect

    ERayome, J.; Romig, S., LLNL

    1998-05-22

    The purpose of this paper is to describe recent trends CIAC has encountered while working with sites that have been compromised. Frequently, the intruders set up and run Internet Relay Chat (IRC) to exchange information and to show off their success at having compromised a site. Invariably, this protocol consumes bandwidth, uses CPU cycles and is a source of embarrassment for the site. This paper focuses on these negative aspects of IRC and concedes that one can cite numerous examples where IRC is used in a positive manner.

  16. Disembodiment in online social interaction: impact of online chat on social support and psychosocial well-being.

    PubMed

    Kang, Seok

    2007-06-01

    This study investigates how disembodiment--that is, transcendence of body constraints in cyberspace--in online chat affects social psychological well-being. The results demonstrate that disembodiment is a strong predictor of increased loneliness and depression, and decreased social support. However, the amount of chat use is a positive contributor to decreased offline estrangement and depression, and increased happiness. These contrasting results suggest that online chat use is a technology for social connection used for offline connectivity, but the disembodiment motive is associated with declines in social support and psychosocial well-being. The investigation of specified motives for online interaction, personal competency, or advanced technological alternatives in interaction is suggested for future research on the effects of online interaction on offline outcomes. PMID:17594274

  17. Inclinometer monitoring system for stability analysis: the western slope of the Bełchatów field case study

    NASA Astrophysics Data System (ADS)

    Cała, Marek; Jakóbczyk, Joanna; Cyran, Katarzyna

    2016-06-01

    The geological structure of the Bełchatów area is very complicated as a result of tectonic and sedimentation processes. The long-term exploitation of the Bełchatów field influenced the development of horizontal displacements. The variety of factors that have impact on the Bełchatów western slope stability conditions, forced the necessity of complex geotechnical monitoring. The geotechnical monitoring of the western slope was carried out with the use of slope inclinometers. From 2005 to 2013 fourteen slope inclinometers were installed, however, currently seven of them are in operation. The present analysis depicts inclinometers situated in the north part of the western slope, for which the largest deformations were registered. The results revealed that the horizontal displacements and formation of slip surfaces are related to complicated geological structure and intensive tectonic deformations in the area. Therefore, the influence of exploitation marked by changes in slope geometry was also noticeable.

  18. Variable Omission of "ne" in Real-Time French Chat: A Corpus-Driven Comparison of Educational and Non-Educational Contexts

    ERIC Educational Resources Information Center

    van Compernolle, Remi A.; Williams, Lawrence

    2009-01-01

    This article reports on the variable omission of the French negative particle "ne" (the first marker of verbal negation) in synchronous (i.e., real-time) electronic communication environments. Patterns of variation in a corpus of non-educational chat (i.e., free, public-access Internet chat) are analyzed and compared to data produced by first-,…

  19. Frequency and Content of Chat Questions by Time of Semester at the University of Central Florida: Implications for Training, Staffing and Marketing

    ERIC Educational Resources Information Center

    Goda, Donna; Bishop, Corinne

    2008-01-01

    The more than 4,000 "chats" received by the University of Central Florida's (UCF) Ask-A-Librarian digital reference service are the subject of this practitioner-based, descriptive case study. Question content from chats received during four semesters between January 2005 and May 2006 are categorized and plotted, by semester, to show the number of…

  20. Developmental Chronology of Preverbal Social Behaviors in Infancy Using the M-CHAT: Baseline for Early Detection of Atypical Social Development

    ERIC Educational Resources Information Center

    Inada, Naoko; Kamio, Yoko; Koyama, Tomonori

    2010-01-01

    This study aimed to identify the age of emergence and subsequent order of preverbal social behaviors, which have not yet been fully clarified. This was accomplished using 16 items of social behaviors extracted from the Modified Checklist for Toddlers with Autism (M-CHAT). The Japanese version of the M-CHAT was completed voluntarily by the parents…

  1. Reflections on CHAT and Freire's Participatory Action Research from the West of Scotland: "Praxis," Politics, and the "Struggle for Meaningful Life"

    ERIC Educational Resources Information Center

    Collins, Chik

    2011-01-01

    This article offers a perspective on the relationship between cultural-historical activity theory (CHAT) and one particular strand of action research--Freirean participatory action research (PAR). It reflects on a research collaboration conducted two decades ago with a community organisation and seeks to "show" the interaction of CHAT and Freirean…

  2. Crystallization of ornithine acetyltransferase from yeast by counter-diffusion and preliminary X-ray study

    SciTech Connect

    Maes, Dominique Crabeel, Marjolaine; Van de Weerdt, Cécile; Martial, Joseph; Peeters, Eveline; Charlier, Daniël; Decanniere, Klaas; Vanhee, Celine; Wyns, Lode; Zegers, Ingrid

    2006-12-01

    A study on the crystallization of ornithine acetyltransferase from yeast, catalysing the fifth step in microbial arginine synthesis, is presented. The use of the counter-diffusion technique removes the disorder present in one dimension in crystals grown by either batch or hanging-drop techniques. A study is presented on the crystallization of ornithine acetyltransferase from yeast, which catalyzes the fifth step in microbial arginine synthesis. The use of the counter-diffusion technique removes the disorder present in one dimension in crystals grown by either the batch or hanging-drop techniques. This makes the difference between useless crystals and crystals that allow successful determination of the structure of the protein. The crystals belong to space group P4, with unit-cell parameters a = b = 66.98, c = 427.09 Å, and a data set was collected to 2.76 Å.

  3. Application of a High-throughput Fluorescent Acetyltransferase Assay to Identify Inhibitors of Homocitrate Synthase

    PubMed Central

    Bulfer, Stacie L.; McQuade, Thomas J.; Larsen, Martha J.; Trievel, Raymond C.

    2011-01-01

    Homocitrate synthase (HCS) catalyzes the first step of L-lysine biosynthesis in fungi by condensing acetyl-Coenzyme A and 2-oxoglutarate to form 3R-homocitrate and Coenzyme A. Due to its conservation in pathogenic fungi, HCS has been proposed as a candidate for antifungal drug design. Here we report the development and validation of a robust, fluorescent assay for HCS that is amenable to high-throughput screening for inhibitors in vitro. Using this assay, Schizosaccharomyces pombe HCS was screened against a diverse library of ~41,000 small molecules. Following confirmation, counter screens, and dose-response analysis, we prioritized over 100 compounds for further in vitro and in vivo analysis. This assay can be readily adapted to screen for small molecule modulators of other acyl-CoA-dependent acyltransferases or enzymes that generate a product with a free sulfhydryl group, including histone acetyltransferases, aminoglycoside N-acetyltransferases, thioesterases and enzymes involved in lipid metabolism. PMID:21073853

  4. The Acetyltransferase Tip60 Is a Critical Regulator of the Differentiation-Dependent Amplification of Human Papillomaviruses

    PubMed Central

    Hong, Shiyuan; Dutta, Anindya

    2015-01-01

    ABSTRACT The life cycle of human papillomaviruses (HPVs) is dependent upon differentiation of the infected host epithelial cell as well as activation of the ataxia telangiectasia mutated (ATM) DNA repair pathway that in normal cells acts to repair double-strand DNA breaks. In normal cells, following DNA damage the acetyltransferase Tip60 must acetylate ATM proteins prior to their full activation by autophosphorylation. E6 proteins have been shown to induce the degradation of Tip60, suggesting that Tip60 action may not be required for activation of the ATM pathway in HPV-positive cells. We investigated what role, if any, Tip60 plays in regulating the differentiation-dependent HPV life cycle. Our study indicates that Tip60 levels and activity are increased in cells that stably maintain complete HPV genomes as episomes, while low levels are seen in cells that express only HPV E6 and E7 proteins. Knockdown of Tip60 with short hairpin RNAs in cells that maintain HPV episomes blocked ATM induction and differentiation-dependent genome amplification, demonstrating the critical role of Tip60 in the viral life cycle. The JAK/STAT transcription factor STAT-5 has previously been shown to regulate the phosphorylation of ATM. Our studies demonstrate that STAT-5 regulates Tip60 activation and this occurs in part by targeting glycogen synthase kinase 3β (GSK3β). Inhibition of either STAT-5, Tip60, or GSK3β blocked differentiation-dependent genome amplification. Taken together, our findings identify Tip60 to be an important regulator of HPV genome amplification whose activity during the viral life cycle is controlled by STAT-5 and the kinase GSK3β. IMPORTANCE Human papillomaviruses (HPVs) are the etiological agents of cervical and other anogenital cancers. HPVs regulate their differentiation-dependent life cycle by activation of DNA damage pathways. This study demonstrates that HPVs regulate the ATM DNA damage pathway through the action of the acetyltransferase Tip60

  5. Difficulties in everyday life: young persons with attention-deficit/hyperactivity disorder and autism spectrum disorders perspectives. A chat-log analysis.

    PubMed

    Ahlström, Britt H; Wentz, Elisabet

    2014-01-01

    This study focuses on the everyday life of young persons with attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). There are follow-up studies describing ADHD, and ASD in adults, and residual impairments that affect life. Few qualitative studies have been conducted on the subject of their experiences of everyday life, and even fewer are from young persons' perspectives. This study's aim was to describe how young persons with ADHD and ASD function and how they manage their everyday life based on analyses of Internet-based chat logs. Twelve young persons (7 males and 5 females aged 15-26) diagnosed with ADHD and ASD were included consecutively and offered 8 weeks of Internet-based Support and Coaching (IBSC). Data were collected from 12 chat logs (445 pages of text) produced interactively by the participants and the coaches. Qualitative content analysis was applied. The text was coded and sorted into subthemes and further interpreted into themes. The findings revealed two themes: "fighting against an everyday life lived in vulnerability" with the following subthemes: "difficult things," "stress and rest," and "when feelings and thoughts are a concern"; and the theme "struggling to find a life of one's own" with the following subthemes: "decide and carry out," "making life choices," and "taking care of oneself." Dealing with the problematic situations that everyday encompasses requires personal strength and a desire to find adequate solutions, as well as to discover a role in society. This study, into the provision of support and coaching over the Internet, led to more in-depth knowledge about these young persons' everyday lives and revealed their ability to use IBSC to express the complexity of everyday life for young persons with ADHD and ASD. The implications of the findings are that using online coaching makes available new opportunities for healthcare professionals to acknowledge these young persons' problems. PMID:24875238

  6. Mechanism of the lysosomal membrane enzyme acetyl coenzyme A: alpha-glucosaminide N-acetyltransferase

    SciTech Connect

    Bame, K.J.

    1986-01-01

    Acetyl-CoA:..cap alpha..-glucosaminide N-acetyltransferase is a lysosomal membrane enzyme, deficient in the genetic disease Sanfilippo C syndrome. The enzyme catalyzes the transfer of an acetyl group from cytoplasmic acetyl-CoA to terminal ..cap alpha..-glucosamine residues of heparan sulfate within the organelle. The reaction mechanism was examined using high purified lysosomal membranes from rat liver and human fibroblasts. The N-acetyltransferase reaction is optimal above pH 5.5 and a 2-3 fold stimulation of activity is observed in the presence of 0.1% taurodeoxycholate. Double reciprocal analysis and product inhibition studies indicate that the enzyme works by a Di-Iso Ping Pong Bi Bi mechanism. The binding of acetyl-CoA to the enzyme is measured by exchange label from (/sup 3/H)CoA to acetyl-CoA, and is optimal at pH's above 7.0. The acetyl-enzyme intermediate is formed by incubating membranes with (/sup 3/H)acetyl-CoA. The acetyl group can be transferred to glucosamine, forming (/sup 3/H)N-acetylglucosamine; the transfer is optimal between pH 4 and 5. Lysosomal membranes from Sanfilippo C fibroblasts confirm that these half reactions carried out by the N-acetyltransferase. The enzyme is inactivated by N-bromosuccinimide and diethylpyrocarbonate, indicating that a histidine is involved in the reaction. These results suggest that the histidine residue is at the active site of the enzyme. The properties of the N-acetyltransferase in the membrane, the characterization of the enzyme kinetics, the chemistry of a histidine mediated acetylation and the pH difference across the lysosomal membrane all support a transmembrane acetylation mechanism.

  7. Implication of an Aldehyde Dehydrogenase Gene and a Phosphinothricin N-Acetyltransferase Gene in the Diversity of Pseudomonas cichorii Virulence

    PubMed Central

    Tanaka, Masayuki; Wali, Ullah Md; Nakayashiki, Hitoshi; Fukuda, Tatsuya; Mizumoto, Hiroyuki; Ohnishi, Kouhei; Kiba, Akinori; Hikichi, Yasufumi

    2011-01-01

    Pseudomonas cichorii harbors the hrp genes. hrp-mutants lose their virulence on eggplant but not on lettuce. A phosphinothricin N-acetyltransferase gene (pat) is located between hrpL and an aldehyde dehydrogenase gene (aldH) in the genome of P. cichorii. Comparison of nucleotide sequences and composition of the genes among pseudomonads suggests a common ancestor of hrp and pat between P. cichorii strains and P. viridiflava strains harboring the single hrp pathogenicity island. In contrast, phylogenetic diversification of aldH corresponded to species diversification amongst pseudomonads. In this study, the involvement of aldH and pat in P. cichorii virulence was analyzed. An aldH-deleted mutant (ΔaldH) and a pat-deleted mutant (Δpat) lost their virulence on eggplant but not on lettuce. P. cichorii expressed both genes in eggplant leaves, independent of HrpL, the transcriptional activator for the hrp. Inoculation into Asteraceae species susceptible to P. cichorii showed that the involvement of hrp, pat and aldH in P. cichorii virulence is independent of each other and has no relationship with the phylogeny of Asteraceae species based on the nucleotide sequences of ndhF and rbcL. It is thus thought that not only the hrp genes but also pat and aldH are implicated in the diversity of P. cichorii virulence on susceptible host plant species. PMID:24704843

  8. Competitive Inhibition of Lysine Acetyltransferase 2B by a Small Motif of the Adenoviral Oncoprotein E1A.

    PubMed

    Shi, Shasha; Liu, Ke; Chen, Yanheng; Zhang, Shijun; Lin, Juanyu; Gong, Chenfang; Jin, Quanwen; Yang, Xiang-Jiao; Chen, Ruichuan; Ji, Zhiliang; Han, Aidong

    2016-07-01

    The adenovirus early region 1A (E1A) oncoprotein hijacks host cells via direct interactions with many key cellular proteins, such as KAT2B, also known as PCAF (p300/CBP associated factor). E1A binds the histone acetyltransferase (HAT) domain of KAT2B to repress its transcriptional activation. However, the molecular mechanism by which E1A inhibits the HAT activity is not known. Here we demonstrate that a short and relatively conserved N-terminal motif (cNM) in the intrinsically disordered E1A protein is crucial for KAT2B interaction, and inhibits its HAT activity through a direct competition with acetyl-CoA, but not its substrate histone H3. Molecular modeling together with a series of mutagenesis experiments suggests that the major helix of E1A cNM binds to a surface of the acetyl-CoA pocket of the KAT2B HAT domain. Moreover, transient expression of the cNM peptide is sufficient to inhibit KAT2B-specific H3 acetylation H3K14ac in vivo Together, our data define an essential motif cNM in N-terminal E1A as an acetyl-CoA entry blocker that directly associates with the entrance of acetyl-CoA binding pocket to block the HAT domain access to its cofactor. PMID:27143356

  9. Absence of Rtt109p, a fungal-specific histone acetyltransferase, results in improved acetic acid tolerance of Saccharomyces cerevisiae.

    PubMed

    Cheng, Cheng; Zhao, Xinqing; Zhang, Mingming; Bai, Fengwu

    2016-03-01

    RTT109 is a histone acetyltransferase for the acetylation of histone H3. It is still not clear whether RTT109 plays a role in regulation of gene expression under environmental stresses. In this study, the involvement of RTT109 in acetic acid stress tolerance of Saccharomyces cerevisiae was investigated. It was revealed that the absence of RTT109 enhanced resistance to 5.5 g L(-1) acetic acid, which was indicated by improved growth of RTT109Δ mutant compared with that of the wild-type BY4741 strain. Meanwhile, the lag phase was shortened for 48 h and glucose consumption completed 36 h in advance for RTT109Δ mutant compared to the wild-type strain, with ethanol production rate increased from 0.39 to 0.60 g L(-1) h(-1). Significantly, elevated transcription levels of HSP12, CTT1 and GSH1, as well as increased activities of antioxidant enzymes were observed in RTT109Δ under acetic acid stress. Improved flocculation of RTT109Δ compared to that of the control strain BY4741 under the acetic acid stress was also observed. These results suggest that the absence of RTT109 not only activates transcription of stress responsive genes, but also improves resistance to oxidative stress, which ultimately contributes to improved acetic acid tolerance in S. cerevisiae. PMID:26851403

  10. An efficient high-throughput screening method for MYST family acetyltransferases, a new class of epigenetic drug targets.

    PubMed

    Falk, Hendrik; Connor, Theresa; Yang, Hong; Loft, Karen J; Alcindor, Joanne L; Nikolakopoulos, George; Surjadi, Regina N; Bentley, John D; Hattarki, Meghan K; Dolezal, Olan; Murphy, James M; Monahan, Brendon J; Peat, Thomas S; Thomas, Tim; Baell, Jonathan B; Parisot, John P; Street, Ian P

    2011-12-01

    Epigenetic aberrations are increasingly regarded as key factors in cancer progression. Recently, deregulation of histone acetyltransferases (HATs) has been linked to several types of cancer. Monocytic leukemia zinc finger protein (MOZ) is a member of the MYST family of HATs, which regulate gene expression in cell proliferation and differentiation. Deregulation of these processes through constitutively active MOZ fusion proteins gives rise to the formation of leukemic stem cells, rendering MOZ an excellent target for treating myeloid leukemia. The authors implemented a hit discovery campaign to identify small-molecule inhibitors of MOZ-HAT activity. They developed a robust, homogeneous assay measuring the acetylation of synthetic histone peptides. In a primary screening campaign testing 243 000 lead-like compounds, they identified inhibitors from several chemical classes. Secondary assays were used to eliminate assay-interfering compounds and prioritize confirmed hits. This study establishes a new high-throughput assay for HAT activity and could provide the foundation for the development of a new class of drugs for the treatment of leukemias. PMID:22086725

  11. Synergistic action of histone acetyltransferase GCN5 and receptor CLAVATA1 negatively affects ethylene responses in Arabidopsis thaliana.

    PubMed

    Poulios, Stylianos; Vlachonasios, Konstantinos E

    2016-02-01

    GENERAL CONTROL NON-REPRESSIBLE 5 (GCN5) is a histone acetyltransferase (HAT) and the catalytic subunit of several multicomponent HAT complexes that acetylate lysine residues of histone H3. Mutants in AtGCN5 display pleiotropic developmental defects including aberrant meristem function. Shoot apical meristem (SAM) maintenance is regulated by CLAVATA1 (CLV1), a receptor kinase that controls the size of the shoot and floral meristems. Upon activation through CLV3 binding, CLV1 signals to the transcription factor WUSCHEL (WUS), restricting WUS expression and thus the meristem size. We hypothesized that GCN5 and CLV1 act together to affect SAM function. Using genetic and molecular approaches, we generated and characterized clv gcn5 mutants. Surprisingly, the clv1-1 gcn5-1 double mutant exhibited constitutive ethylene responses, suggesting that GCN5 and CLV signaling act synergistically to inhibit ethylene responses in Arabidopsis. This genetic and molecular interaction was mediated by ETHYLENE INSENSITIVE 3/ EIN3-LIKE1 (EIN3/EIL1) transcription factors. Our data suggest that signals from the CLV transduction pathway reach the GCN5-containing complexes in the nucleus and alter the histone acetylation status of ethylene-responsive genes, thus translating the CLV information to transcriptional activity and uncovering a link between histone acetylation and SAM maintenance in the complex mode of ethylene signaling. PMID:26596766

  12. RNA Cytidine Acetyltransferase of Small-Subunit Ribosomal RNA: Identification of Acetylation Sites and the Responsible Acetyltransferase in Fission Yeast, Schizosaccharomyces pombe

    PubMed Central

    Taoka, Masato; Ishikawa, Daisuke; Nobe, Yuko; Ishikawa, Hideaki; Yamauchi, Yoshio; Terukina, Goro; Nakayama, Hiroshi; Hirota, Kouji; Takahashi, Nobuhiro; Isobe, Toshiaki

    2014-01-01

    The eukaryotic small-subunit (SSU) ribosomal RNA (rRNA) has two evolutionarily conserved acetylcytidines. However, the acetylation sites and the acetyltransferase responsible for the acetylation have not been identified. We performed a comprehensive MS-based analysis covering the entire sequence of the fission yeast, Schizosaccharomyces pombe, SSU rRNA and identified two acetylcytidines at positions 1297 and 1815 in the 3′ half of the rRNA. To identify the enzyme responsible for the cytidine acetylation, we searched for an S. pombe gene homologous to TmcA, a bacterial tRNA N-acetyltransferase, and found one potential candidate, Nat10. A temperature-sensitive strain of Nat10 with a mutation in the Walker A type ATP-binding motif abolished the cytidine acetylation in SSU rRNA, and the wild-type Nat10 supplemented to this strain recovered the acetylation, providing evidence that Nat10 is necessary for acetylation of SSU rRNA. The Nat10 mutant strain showed a slow-growth phenotype and was defective in forming the SSU rRNA from the precursor RNA, suggesting that cytidine acetylation is necessary for ribosome assembly. PMID:25402480

  13. Conformational flexibility and subunit arrangement of the modular yeast Spt-Ada-Gcn5 acetyltransferase complex.

    PubMed

    Setiaputra, Dheva; Ross, James D; Lu, Shan; Cheng, Derrick T; Dong, Meng-Qiu; Yip, Calvin K

    2015-04-17

    The Spt-Ada-Gcn5 acetyltransferase (SAGA) complex is a highly conserved, 19-subunit histone acetyltransferase complex that activates transcription through acetylation and deubiquitination of nucleosomal histones in Saccharomyces cerevisiae. Because SAGA has been shown to display conformational variability, we applied gradient fixation to stabilize purified SAGA and systematically analyzed this flexibility using single-particle EM. Our two- and three-dimensional studies show that SAGA adopts three major conformations, and mutations of specific subunits affect the distribution among these. We also located the four functional modules of SAGA using electron microscopy-based labeling and transcriptional activator binding analyses and show that the acetyltransferase module is localized in the most mobile region of the complex. We further comprehensively mapped the subunit interconnectivity of SAGA using cross-linking mass spectrometry, revealing that the Spt and Taf subunits form the structural core of the complex. These results provide the necessary restraints for us to generate a model of the spatial arrangement of all SAGA subunits. According to this model, the chromatin-binding domains of SAGA are all clustered in one face of the complex that is highly flexible. Our results relate information of overall SAGA structure with detailed subunit level interactions, improving our understanding of its architecture and flexibility. PMID:25713136

  14. Conformational Flexibility and Subunit Arrangement of the Modular Yeast Spt-Ada-Gcn5 Acetyltransferase Complex*

    PubMed Central

    Setiaputra, Dheva; Ross, James D.; Lu, Shan; Cheng, Derrick T.; Dong, Meng-Qiu; Yip, Calvin K.

    2015-01-01

    The Spt-Ada-Gcn5 acetyltransferase (SAGA) complex is a highly conserved, 19-subunit histone acetyltransferase complex that activates transcription through acetylation and deubiquitination of nucleosomal histones in Saccharomyces cerevisiae. Because SAGA has been shown to display conformational variability, we applied gradient fixation to stabilize purified SAGA and systematically analyzed this flexibility using single-particle EM. Our two- and three-dimensional studies show that SAGA adopts three major conformations, and mutations of specific subunits affect the distribution among these. We also located the four functional modules of SAGA using electron microscopy-based labeling and transcriptional activator binding analyses and show that the acetyltransferase module is localized in the most mobile region of the complex. We further comprehensively mapped the subunit interconnectivity of SAGA using cross-linking mass spectrometry, revealing that the Spt and Taf subunits form the structural core of the complex. These results provide the necessary restraints for us to generate a model of the spatial arrangement of all SAGA subunits. According to this model, the chromatin-binding domains of SAGA are all clustered in one face of the complex that is highly flexible. Our results relate information of overall SAGA structure with detailed subunit level interactions, improving our understanding of its architecture and flexibility. PMID:25713136

  15. MOZ and MORF acetyltransferases: Molecular interaction, animal development and human disease.

    PubMed

    Yang, Xiang-Jiao

    2015-08-01

    Lysine residues are subject to many forms of covalent modification and one such modification is acetylation of the ε-amino group. Initially identified on histone proteins in the 1960s, lysine acetylation is now considered as an important form of post-translational modification that rivals phosphorylation. However, only about a dozen of human lysine acetyltransferases have been identified. Among them are MOZ (monocytic leukemia zinc finger protein; a.k.a. MYST3 and KAT6A) and its paralog MORF (a.k.a. MYST4 and KAT6B). Although there is a distantly related protein in Drosophila and sea urchin, these two enzymes are vertebrate-specific. They form tetrameric complexes with BRPF1 (bromodomain- and PHD finger-containing protein 1) and two small non-catalytic subunits. These two acetyltransferases and BRPF1 play key roles in various developmental processes; for example, they are important for development of hematopoietic and neural stem cells. The human KAT6A and KAT6B genes are recurrently mutated in leukemia, non-hematologic malignancies, and multiple developmental disorders displaying intellectual disability and various other abnormalities. In addition, the BRPF1 gene is mutated in childhood leukemia and adult medulloblastoma. Therefore, these two acetyltransferases and their partner BRPF1 are important in animal development and human disease. PMID:25920810

  16. Assay for peptidoglycan O-acetyltransferase: a potential new antibacterial target.

    PubMed

    Moynihan, Patrick J; Clarke, Anthony J

    2013-08-15

    The O-acetylation of peptidoglycan occurs at the C-6 hydroxyl group of muramoyl residues in many human pathogens, both gram positive and gram negative, such as Staphylococcus aureus and species of Campylobacter, Helicobacter, Neisseria, and Bacillus, including Bacillus anthracis. The process is a maturation event being catalyzed either by integral membrane O-acetylpeptidoglycan transferase (Oat) of gram-positive bacteria or by a two-component peptidoglycan O-acetyltransferase system (PatA/PatB) in gram-negative cells. Here, we describe the development of the first in vitro assay for any peptidoglycan O-acetyltransferase using PatB from Neisseria gonorrhoeae as the model enzyme. This assay is based on the use of chromogenic p-nitrophenyl acetate as the donor substrate and chitooligosaccharides as model acceptor substrates in place of peptidoglycan. The identity of the O-acetylated chitooligosaccharides was confirmed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Rates of transacetylations were determined spectrophotometrically by monitoring p-nitrophenol release after accounting for both spontaneous and enzyme-catalyzed hydrolysis of the acetate donor. Conditions were established for use of the assay in microtiter plate format, and its applicability was demonstrated by determining the first Michaelis-Menten kinetic parameters for PatB. The assay is readily amenable for application in the high-throughput screening for potential inhibitors of peptidoglycan O-acetyltransferases that may prove to be leads for novel classes of antibiotics. PMID:23660013

  17. "De-humanised females and Amazonians": British wartime fashion and its representation in Home chat, 1914-1918.

    PubMed

    Buckley, Cheryl

    2002-01-01

    Popular representations of the fashionably dressed female body between 1914 and 1918 were highly contradictory and, as this essay will show, were sharply delineated in Home Chat, one of a growing number of relatively new women's magazines which addressed the needs of an expanding skilled working-class and lower-middle-class female readership. Aiming to provide women with practical advice about all aspects of their daily lives, from the traditional concerns of fashion and beauty, marriage and children, to the more contentious issue of women's aspirations beyond the home, Home Chat was uniquely placed to reflect shifting gender and class relations. PMID:17484102

  18. Association of Choline Acetyltransferase Gene Polymorphisms (SNPs rs868750G/A, rs1880676G/A, rs2177369G/A and rs3810950G/A) with Alzheimer’s Disease Risk: A Meta-Analysis

    PubMed Central

    Yuan, Hai; Xia, Qing; Ling, Kang; Wang, Xiaotong; Wang, Xiumin; Du, Xunping

    2016-01-01

    Background Epidemiological studies have investigated the role of choline acetyltransferase (ChAT) in Alzheimer’s disease (AD). ChAT gene polymorphisms (SNPs rs868750G/A, rs1880676G/A, rs2177369G/A, and rs3810950G/A) may be associated with the risk of AD. In this meta-analysis, we determined the relationship between the four polymorphisms and the risk of AD. Methods We searched MEDLINE, EMBASE, and HuGEnet databases for studies linking the four polymorphisms with AD risk. We included 16 articles in our meta-analysis to assess the association between the four polymorphisms and susceptibility to AD by calculating the pooled odds ratios (ORs) and 95% confidence intervals (CIs). Results The combined results showed no significant association with rs1880676G/A and rs2177369G/A polymorphisms. The risk of AD (GG+GA versus AA: OR = 0.01, 95%CI = 0.01–0.02, P < 0.05; GG versus GA+AA: OR = 0.85, 95%CI = 0.72–1.00, P = 0.05; GA versus AA: OR = 0.60, 95% CI = 0.37–0.98, P = 0.04) with rs868750G/A polymorphism, or the association of rs3810950G/A polymorphism with AD risk in the overall population (GA versus AA: OR = 0.64, 95% CI = 0.44–0.93, P = 0.02; GG+GA versus AA: OR = 0.62, 95% CI = 0.39–0.97, P = 0.04) or Asian group (GA versus AA: OR = 0.50, 95% CI = 0.32–0.76, P = 0.001, and GG+GA versus AA: OR = 0.46, 95% CI = 0.30–0.09, P = 0.0002) was demonstrated. Conclusions Our meta-analysis suggested that rs1880670G/A, and rs2177369 G/A polymorphisms were not risk factors for AD. However, rs3810950G/A, or rs868750G/A genetic polymorphism was a genetic risk factor for the development of AD. The rs3810950G/A polymorphism had a negative effect on the risk of AD for GA or GG+GA genotypes compared with AA in the overall population or Asians. PMID:27390868

  19. Automatic Association of Chats and Video Tracks for Activity Learning and Recognition in Aerial Video Surveillance

    PubMed Central

    Hammoud, Riad I.; Sahin, Cem S.; Blasch, Erik P.; Rhodes, Bradley J.; Wang, Tao

    2014-01-01

    We describe two advanced video analysis techniques, including video-indexed by voice annotations (VIVA) and multi-media indexing and explorer (MINER). VIVA utilizes analyst call-outs (ACOs) in the form of chat messages (voice-to-text) to associate labels with video target tracks, to designate spatial-temporal activity boundaries and to augment video tracking in challenging scenarios. Challenging scenarios include low-resolution sensors, moving targets and target trajectories obscured by natural and man-made clutter. MINER includes: (1) a fusion of graphical track and text data using probabilistic methods; (2) an activity pattern learning framework to support querying an index of activities of interest (AOIs) and targets of interest (TOIs) by movement type and geolocation; and (3) a user interface to support streaming multi-intelligence data processing. We also present an activity pattern learning framework that uses the multi-source associated data as training to index a large archive of full-motion videos (FMV). VIVA and MINER examples are demonstrated for wide aerial/overhead imagery over common data sets affording an improvement in tracking from video data alone, leading to 84% detection with modest misdetection/false alarm results due to the complexity of the scenario. The novel use of ACOs and chat messages in video tracking paves the way for user interaction, correction and preparation of situation awareness reports. PMID:25340453

  20. Automatic association of chats and video tracks for activity learning and recognition in aerial video surveillance.

    PubMed

    Hammoud, Riad I; Sahin, Cem S; Blasch, Erik P; Rhodes, Bradley J; Wang, Tao

    2014-01-01

    We describe two advanced video analysis techniques, including video-indexed by voice annotations (VIVA) and multi-media indexing and explorer (MINER). VIVA utilizes analyst call-outs (ACOs) in the form of chat messages (voice-to-text) to associate labels with video target tracks, to designate spatial-temporal activity boundaries and to augment video tracking in challenging scenarios. Challenging scenarios include low-resolution sensors, moving targets and target trajectories obscured by natural and man-made clutter. MINER includes: (1) a fusion of graphical track and text data using probabilistic methods; (2) an activity pattern learning framework to support querying an index of activities of interest (AOIs) and targets of interest (TOIs) by movement type and geolocation; and (3) a user interface to support streaming multi-intelligence data processing. We also present an activity pattern learning framework that uses the multi-source associated data as training to index a large archive of full-motion videos (FMV). VIVA and MINER examples are demonstrated for wide aerial/overhead imagery over common data sets affording an improvement in tracking from video data alone, leading to 84% detection with modest misdetection/false alarm results due to the complexity of the scenario. The novel use of ACOs and chat Sensors 2014, 14 19844 messages in video tracking paves the way for user interaction, correction and preparation of situation awareness reports. PMID:25340453

  1. Cloning, sequencing, and use as a molecular probe of a gene encoding an aminoglycoside 6'-N-acetyltransferase of broad substrate profile.

    PubMed Central

    Terán, F J; Suárez, J E; Mendoza, M C

    1991-01-01

    A gene coding for an aminoglycoside 6'-N-acetyltransferase that was able to modify amikacin was cloned from a plasmid isolated from a clinical strain of Enterobacter cloacae. Sequencing of a 955-bp segment which mediates the modifying activity revealed a single open reading frame of 432 nucleotides that predicted a polypeptide of 144 amino acid residues with a molecular weight of 16,021. Putative ribosomal binding sites and -10 and -35 sequences were located at the 5' end of the gene. The size of the polypeptide was confirmed through minicell analysis of the expression products of plasmids containing the sequence. The use of the gene as a molecular probe revealed its specificity toward strains harboring genes coding for related enzymes. This probe is therefore useful for epidemiological studies. Images PMID:2069376

  2. Inhibition of p300 lysine acetyltransferase activity by luteolin reduces tumor growth in head and neck squamous cell carcinoma (HNSCC) xenograft mouse model.

    PubMed

    Selvi, Ruthrotha B; Swaminathan, Amrutha; Chatterjee, Snehajyoti; Shanmugam, Muthu K; Li, Feng; Ramakrishnan, Gowsica B; Siveen, Kodappully Sivaraman; Chinnathambi, Arunachalam; Zayed, M Emam; Alharbi, Sulaiman Ali; Basha, Jeelan; Bhat, Akshay; Vasudevan, Madavan; Dharmarajan, Arunasalam; Sethi, Gautam; Kundu, Tapas K

    2015-12-22

    Chromatin acetylation is attributed with distinct functional relevance with respect to gene expression in normal and diseased conditions thereby leading to a topical interest in the concept of epigenetic modulators and therapy. We report here the identification and characterization of the acetylation inhibitory potential of an important dietary flavonoid, luteolin. Luteolin was found to inhibit p300 acetyltransferase with competitive binding to the acetyl CoA binding site. Luteolin treatment in a xenografted tumor model of head and neck squamous cell carcinoma (HNSCC), led to a dramatic reduction in tumor growth within 4 weeks corresponding to a decrease in histone acetylation. Cells treated with luteolin exhibit cell cycle arrest and decreased cell migration. Luteolin treatment led to an alteration in gene expression and miRNA profile including up-regulation of p53 induced miR-195/215, let7C; potentially translating into a tumor suppressor function. It also led to down-regulation of oncomiRNAs such as miR-135a, thereby reflecting global changes in the microRNA network. Furthermore, a direct correlation between the inhibition of histone acetylation and gene expression was established using chromatin immunoprecipitation on promoters of differentially expressed genes. A network of dysregulated genes and miRNAs was mapped along with the gene ontology categories, and the effects of luteolin were observed to be potentially at multiple levels: at the level of gene expression, miRNA expression and miRNA processing. PMID:26517526

  3. Inhibition of p300 lysine acetyltransferase activity by luteolin reduces tumor growth in head and neck squamous cell carcinoma (HNSCC) xenograft mouse model

    PubMed Central

    Selvi, Ruthrotha B.; Swaminathan, Amrutha; Chatterjee, Snehajyoti; Shanmugam, Muthu K.; Li, Feng; Ramakrishnan, Gowsica B.; Siveen, Kodappully Sivaraman; Chinnathambi, Arunachalam; Zayed, M. Emam; Alharbi, Sulaiman Ali; Basha, Jeelan; Bhat, Akshay; Vasudevan, Madavan; Dharmarajan, Arunasalam; Sethi, Gautam; Kundu, Tapas K.

    2015-01-01

    Chromatin acetylation is attributed with distinct functional relevance with respect to gene expression in normal and diseased conditions thereby leading to a topical interest in the concept of epigenetic modulators and therapy. We report here the identification and characterization of the acetylation inhibitory potential of an important dietary flavonoid, luteolin. Luteolin was found to inhibit p300 acetyltransferase with competitive binding to the acetyl CoA binding site. Luteolin treatment in a xenografted tumor model of head and neck squamous cell carcinoma (HNSCC), led to a dramatic reduction in tumor growth within 4 weeks corresponding to a decrease in histone acetylation. Cells treated with luteolin exhibit cell cycle arrest and decreased cell migration. Luteolin treatment led to an alteration in gene expression and miRNA profile including up-regulation of p53 induced miR-195/215, let7C; potentially translating into a tumor suppressor function. It also led to down-regulation of oncomiRNAs such as miR-135a, thereby reflecting global changes in the microRNA network. Furthermore, a direct correlation between the inhibition of histone acetylation and gene expression was established using chromatin immunoprecipitation on promoters of differentially expressed genes. A network of dysregulated genes and miRNAs was mapped along with the gene ontology categories, and the effects of luteolin were observed to be potentially at multiple levels: at the level of gene expression, miRNA expression and miRNA processing. PMID:26517526

  4. The enhancing effect of genistein on apoptosis induced by trichostatin A in lung cancer cells with wild type p53 genes is associated with upregulation of histone acetyltransferase.

    PubMed

    Wu, Tzu-Chin; Lin, Yi-Chin; Chen, Hsiao-Ling; Huang, Pei-Ru; Liu, Shang-Yu; Yeh, Shu-Lan

    2016-02-01

    Genistein has been shown to enhance the antitumor activity of trichostatin A (TSA) in human lung carcinoma A549 cells. However, whether the combined treatment exerts the same effect in other lung cancer cells is unclear. In the present study we first compared the enhancing effect of genistein on the antitumor effect of TSA in ABC-1, NCI-H460 (H460) and A549 cells. Second, we investigated whether the effects of genistein are associated with increased histone/non-histone protein acetylation. We found that the enhancing effect of genistein on cell-growth-arrest in ABC-1 cells (p53 mutant) was less than in A549 and H460 cells. Genistein enhanced TSA induced apoptosis in A549 and H460 cells rather than in ABC-1 cells. After silencing p53 expression in A549 and H460 cells, the enhancing effect of genistein was diminished. In addition, genistein increased TSA-induced histone H3/H4 acetylation in A549 and H460 cells. Genistein also increased p53 acetylation in H460 cells. The inhibitor of acetyltransferase, anacardic acid, diminished the enhancing effect of genistein on all TSA-induced histone/p53 acetylation and apoptosis. Genistein in combination with TSA increased the expression of p300 protein, an acetyltransferase, in A549 and NCI-H460 cells. Furthermore, we demonstrated that genistein also enhanced the antitumor effect of genistein in A549-tumor-bearing mice. Taken together, these results suggest that the enhancing effects of genistein on TSA-induced apoptosis in lung cancer cells were p53-dependent and were associated with histone/non-histone protein acetylation. PMID:26768552

  5. Direct Introduction of Genes into Rats and Expression of the Genes

    NASA Astrophysics Data System (ADS)

    Benvenisty, Nissim; Reshef, Lea

    1986-12-01

    A method of introducing actively expressed genes into intact mammals is described. DNA precipitated with calcium phosphate has been injected intraperitoneally into newborn rats. The injected genes have been taken up and expressed by the animal tissues. To examine the generality of the method we have injected newborn rats with the chloramphenicol acetyltransferase prokaryotic gene fused with various viral and cellular gene promoters and the gene for hepatitis B surface antigen, and we observed appearance of chloramphenicol acetyltransferase activity and hepatitis B surface antigen in liver and spleen. In addition, administration of genes coding for hormones (insulin or growth hormone) resulted in their expression.

  6. Nonchromatographic assay for expression of the chloramphenicol acetyltransferase gene in eukaryotic cells

    SciTech Connect

    Sleigh, M.J.

    1986-01-01

    A rapid procedure is described for assaying chloramphenicol acetyltranserase (CAT) enzyme activity following transfection of the CAT gene into eukaryotic cells. CAT enzyme activity in cell extracts catalyzes the transfer of (/sup 14/C)acetyl groups from labeled acetyl coenzyme A to unlabeled chloramphenicol. Labeled reaction product is quantitated by liquid scintillation counting after extraction into ethyl acetate. The method is valid for use with transfected cell extracts only if the extracts are first heated to 65/sup 0/C to remove a factor which degrades acetyl coenzyme A. The revised procedure offers considerable advantages in speed and ease of performance over the chromatographic assay in current use.

  7. Psychological Well-Being in Parents of Children with Angelman, Cornelia de Lange and Cri du Chat Syndromes

    ERIC Educational Resources Information Center

    Griffith, G. M.; Hastings, R. P.; Oliver, C.; Howlin, P.; Moss, J.; Petty, J.; Tunnicliffe, P.

    2011-01-01

    Background: The current study focuses on mothers and fathers of children with three rare genetic syndromes that are relatively unexplored in terms of family experience: Angelman syndrome, Cornelia de Lange syndrome and Cri du Chat syndrome. Method: Parents of children with Angelman syndrome (n = 15), Cornelia de Lange syndrome (n = 16) and Cri du…

  8. A Description of Adaptive and Maladaptive Behaviour in Children and Adolescents with Cri-du-Chat Syndrome

    ERIC Educational Resources Information Center

    Teixeira, M. C. T. V.; Emerich, D. R.; Orsati, F. T.; Rimerio, R. C.; Gatto, K. R.; Chappaz, I. O.; Kim, C. A.

    2011-01-01

    Background: Psychological tests can be useful to record adaptive and maladaptive behaviours of children with intellectual disability. The objective of this study was to describe the adaptive and maladaptive behaviour of children and adolescents with Cri-du-chat syndrome. Methods: The sample consisted of 10 children and adolescents with Cri-du-chat…

  9. "O Que Diriam Sobre Os Portugueses?????" [What Would You Say about Portuguese People?]: Intercultural Curiosity in Multilingual Chat-Rooms

    ERIC Educational Resources Information Center

    Araujo e Sa, Maria Helena; de Carlo, Maddalena; Melo-Pfeifer, Silvia

    2010-01-01

    In this study, we intend to discuss questioning as a sign of Intercultural Communicative Competence in plurilingual environments, stressing the relationship between questioning and the process of developing discovery skills in Romance chat-rooms. Focusing specifically on episodes beginning with intercultural questioning, we will analyse: (1)…

  10. Looking from a CHAT-IT Perspective to Undergraduate Mexican Physics: Organizational Trajectories or Professors as Agents of Change?

    ERIC Educational Resources Information Center

    Kahveci, Ajda

    2010-01-01

    Recent elaborations on cultural-historical activity theory (CHAT) (Engestrom et al., eds., "Perspectives on activity theory." New York: Cambridge University Press, "1999") and its relation to organizational theories have produced a theoretical amalgam of these earlier ideas, which allow for the exploration of learning in formal organizational…

  11. Prisons and Primary Schools: Using CHAT to Analyse the Relationship between Developing Identity, Developing Musicianship and Transformative Processes

    ERIC Educational Resources Information Center

    Henley, Jennie

    2015-01-01

    This paper draws on three different research projects to demonstrate the use of an expanded model of Cultural Historical Activity Theory (CHAT), developed as part of a doctoral research study. The first project is an evaluation of the impacts of a Music Partnership Project within Primary and Secondary schools. The second project is an evaluation…

  12. Deutsch, Doyc or Doitsch? Chatters as Languagers--The Case of a German-Turkish Chat Room

    ERIC Educational Resources Information Center

    Hinnenkamp, Volker

    2008-01-01

    The paper looks at the process of online-languaging of adolescents with a migratory and ethnic Turkish background in a diasporic chat room. The multiple resources and voices used are analysed. One particular example is looked at more thoroughly to illustrate the process of languaging and how it is legitimised by the chatters themselves. Finally,…

  13. Reliability and Validity of the Japanese Version of the Modified Checklist for Autism in Toddlers (M-CHAT)

    ERIC Educational Resources Information Center

    Inada, Naoko; Koyama, Tomonori; Inokuchi, Eiko; Kuroda, Miho; Kamio, Yoko

    2011-01-01

    Early detection and intervention is essential for children with autism spectrum disorders (ASD). Therefore, we examined the reliability and validity of the Japanese version of the Modified Checklist for autism in toddlers (M-CHAT), a 23-item, yes-no questionnaire regarding early autistic symptoms completed by parents of children at 18-24 months of…

  14. Examination of the Properties of the Modified Checklist for Autism in Toddlers (M-CHAT) in a Population Sample

    ERIC Educational Resources Information Center

    Yama, Brie; Freeman, Tom; Graves, Erin; Yuan, Su; Campbell, M. Karen

    2012-01-01

    This study examines the following properties of the Modified Checklist for Autism in Toddlers (M-CHAT) in an unselected low-risk sample: (a) the maximum age for screen administration; (b) the positive screen rate in the absence of follow-up telephone interviews and; (c) the distributional properties of positive screens. Data came from a…

  15. Voice vs. Text Chats: Their Efficacy for Learning Probing Questions by Non-Native Speaking Medical Professionals in Online Courses

    ERIC Educational Resources Information Center

    Ellis, Olga

    2012-01-01

    Through an English for Specific Purposes (ESP): Communication in Nursing online course, the present study examines the efficacy of synchronous voice-based and text-based chats as instructional and communicative modes in learning to use open questions for probing in therapeutic dialogues by non-native speaking (NNS) participants, students of a…

  16. Social Behavior and Characteristics of Autism Spectrum Disorder in Angelman, Cornelia de Lange, and Cri du Chat Syndromes

    ERIC Educational Resources Information Center

    Moss, Joanna; Howlin, Patricia; Hastings, Richard Patrick; Beaumont, Sarah; Griffith, Gemma M.; Petty, Jane; Tunnicliffe, Penny; Yates, Rachel; Villa, Darrelle; Oliver, Chris

    2013-01-01

    We evaluated autism spectrum disorder (ASD) characteristics and social behavior in Angelman (AS; "n" ?=? 19; mean age ?=?10.35 years), Cornelia de Lange (CdLS; "n" ?=? 15; mean age ?=?12.40 years), and Cri du Chat (CdCS, also known as 5 p-syndrome; "n" ?=? 19; mean age ?=? 8.80 years) syndromes. The proportion of…

  17. Evaluating Reliability and Predictive Validity of the Persian Translation of Quantitative Checklist for Autism in Toddlers (Q-CHAT)

    PubMed Central

    Mohammadian, Mehrdad; Mohammadi, Mohammad Reza; Karimi, Issa

    2015-01-01

    Objective: Early screening of autism increases the chance of receiving timely intervention. Using the Parent Report Questionnaires is effective in screening autism. The Q-CHAT is a new instrument that has shown several advantages than other screening tools. Because there is no adequate tool for the early screening of autistic traits in Iranian children, we aimed to investigate the adequacy of the Persian translation of Q-CHAT. Method: At first, we prepared the Persian translation of the Quantitative Checklist for Autism in Toddlers (Q-CHAT). After that, an appropriate sample was selected and the check list was administered. Our sample included 100 children in two groups (typically developing and autistic children) who had been selected conveniently. Pearson’s r was used to determine test-retest reliability, and Cronbach’s alpha coefficient was used to explore the internal consistency of Q-CHAT. We used the receiver operating characteristics curve (ROC) to investigate whether Q-CHAT can adequately discriminate between typically developing and ASD children or not. Data analysis was carried out by SPSS 19. Result: The typically developing group consisted of 50 children with the mean age of 27.14 months, and the ASD group included50 children with the mean age of 29.62 months. The mean of the total score for the typically developing group was 22.4 (SD=6.26) on Q-CHAT and it was 50.94 (SD=12.35) for the ASD group, which was significantly different (p=0.00).The Cronbach’s alpha coefficient of the checklist was 0.886, and test-retest reliability was calculated as 0.997 (p<0.01). The estimated area under the curve (AUC) was 0.971. It seems that the total score equal to 30 can be a good cut point to identify toddlers who are at risk of autism (sensitivity= 0.96 and specificity= 0.90). Conclusion: The Persian translation of Q-CHAT has good reliability and predictive validity and can be used as a screening tool to detect 18 to 24 months old children who are at risk of

  18. The Chromatin Regulator BRPF3 Preferentially Activates the HBO1 Acetyltransferase but Is Dispensable for Mouse Development and Survival.

    PubMed

    Yan, Kezhi; You, Linya; Degerny, Cindy; Ghorbani, Mohammad; Liu, Xin; Chen, Lulu; Li, Lin; Miao, Dengshun; Yang, Xiang-Jiao

    2016-02-01

    To interpret epigenetic information, chromatin readers utilize various protein domains for recognition of DNA and histone modifications. Some readers possess multidomains for modification recognition and are thus multivalent. Bromodomain- and plant homeodomain-linked finger-containing protein 3 (BRPF3) is such a chromatin reader, containing two plant homeodomain-linked fingers, one bromodomain and a PWWP domain. However, its molecular and biological functions remain to be investigated. Here, we report that endogenous BRPF3 preferentially forms a tetrameric complex with HBO1 (also known as KAT7) and two other subunits but not with related acetyltransferases such as MOZ, MORF, TIP60, and MOF (also known as KAT6A, KAT6B, KAT5, and KAT8, respectively). We have also characterized a mutant mouse strain with a lacZ reporter inserted at the Brpf3 locus. Systematic analysis of β-galactosidase activity revealed dynamic spatiotemporal expression of Brpf3 during mouse embryogenesis and high expression in the adult brain and testis. Brpf3 disruption, however, resulted in no obvious gross phenotypes. This is in stark contrast to Brpf1 and Brpf2, whose loss causes lethality at E9.5 and E15.5, respectively. In Brpf3-null mice and embryonic fibroblasts, RT-quantitative PCR uncovered no changes in levels of Brpf1 and Brpf2 transcripts, confirming no compensation from them. These results indicate that BRPF3 forms a functional tetrameric complex with HBO1 but is not required for mouse development and survival, thereby distinguishing BRPF3 from its paralogs, BRPF1 and BRPF2. PMID:26677226

  19. An Approach to Identify SNPs in the Gene Encoding Acetyl-CoA Acetyltransferase-2 (ACAT-2) and Their Proposed Role in Metabolic Processes in Pig

    PubMed Central

    Song, Ki Duk; Sharma, Neelesh; Kim, Jeong Hyun; Kim, Nam Eun; Lee, Sung Jin; Kang, Chul Woong; Oh, Sung Jong; Jeong, Dong Kee

    2014-01-01

    The novel liver protein acetyl-CoA acetyltransferase-2 (ACAT2) is involved in the beta-oxidation and lipid metabolism. Its comprehensive relative expression, in silico non-synonymous single nucleotide polymorphism (nsSNP) analysis, as well as its annotation in terms of metabolic process with another protein from the same family, namely, acetyl-CoA acyltransferase-2 (ACAA2) was performed in Sus scrofa. This investigation was conducted to understand the most important nsSNPs of ACAT2 in terms of their effects on metabolic activities and protein conformation. The two most deleterious mutations at residues 122 (I to V) and 281 (R to H) were found in ACAT2. Validation of expression of genes in the laboratory also supported the idea of differential expression of ACAT2 and ACAA2 conceived through the in silico analysis. Analysis of the relative expression of ACAT2 and ACAA2 in the liver tissue of Jeju native pig showed that the former expressed significantly higher (P<0.05). Overall, the computational prediction supported by wet laboratory analysis suggests that ACAT2 might contribute more to metabolic processes than ACAA2 in swine. Further associations of SNPs in ACAT2 with production traits might guide efforts to improve growth performance in Jeju native pigs. PMID:25050817

  20. New N-Acetyltransferase Fold in the Structure and Mechanism of the Phosphonate Biosynthetic Enzyme FrbF

    SciTech Connect

    Bae, Brian; Cobb, Ryan E.; DeSieno, Matthew A.; Zhao, Huimin; Nair, Satish K.

    2015-10-15

    The enzyme FrbF from Streptomyces rubellomurinus has attracted significant attention due to its role in the biosynthesis of the antimalarial phosphonate FR-900098. The enzyme catalyzes acetyl transfer onto the hydroxamate of the FR-900098 precursors cytidine 5'-monophosphate-3-aminopropylphosphonate and cytidine 5'-monophosphate-N-hydroxy-3-aminopropylphosphonate. Despite the established function as a bona fide N-acetyltransferase, FrbF shows no sequence similarity to any member of the GCN5-like N-acetyltransferase (GNAT) superfamily. Here, we present the 2.0 {angstrom} resolution crystal structure of FrbF in complex with acetyl-CoA, which demonstrates a unique architecture that is distinct from those of canonical GNAT-like acetyltransferases. We also utilized the co-crystal structure to guide structure-function studies that identified the roles of putative active site residues in the acetyltransferase mechanism. The combined biochemical and structural analyses of FrbF provide insights into this previously uncharacterized family of N-acetyltransferases and also provide a molecular framework toward the production of novel N-acyl derivatives of FR-900098.

  1. New N-acetyltransferase fold in the structure and mechanism of the phosphonate biosynthetic enzyme FrbF.

    PubMed

    Bae, Brian; Cobb, Ryan E; DeSieno, Matthew A; Zhao, Huimin; Nair, Satish K

    2011-10-14

    The enzyme FrbF from Streptomyces rubellomurinus has attracted significant attention due to its role in the biosynthesis of the antimalarial phosphonate FR-900098. The enzyme catalyzes acetyl transfer onto the hydroxamate of the FR-900098 precursors cytidine 5'-monophosphate-3-aminopropylphosphonate and cytidine 5'-monophosphate-N-hydroxy-3-aminopropylphosphonate. Despite the established function as a bona fide N-acetyltransferase, FrbF shows no sequence similarity to any member of the GCN5-like N-acetyltransferase (GNAT) superfamily. Here, we present the 2.0 Å resolution crystal structure of FrbF in complex with acetyl-CoA, which demonstrates a unique architecture that is distinct from those of canonical GNAT-like acetyltransferases. We also utilized the co-crystal structure to guide structure-function studies that identified the roles of putative active site residues in the acetyltransferase mechanism. The combined biochemical and structural analyses of FrbF provide insights into this previously uncharacterized family of N-acetyltransferases and also provide a molecular framework toward the production of novel N-acyl derivatives of FR-900098. PMID:21865168

  2. Teachers' instructional goals for science practice: Identifying knowledge gaps using cultural-historical activity theory (CHAT)

    NASA Astrophysics Data System (ADS)

    Farrar, Cynthia Hamen

    In AP Biology, the course goal, with respect to scientific acts and reasoning, has recently shifted toward a reform goal of science practice, where the goal is for students to have a scientific perspective that views science as a practice of a community rather than a body of knowledge. Given this recent shift, this study is interested in the gaps that may exist between an individual teacher's instructional goal and the goals of the AP Biology course. A Cultural-Historical Activity Theory (CHAT) methodology and perspective is used to analyze four teachers' knowledge, practice, and learning. Teachers have content knowledge for teaching, a form of knowledge that is unique for teaching called specialized content knowledge. This specialized content knowledge (SCK) defines their instructional goals, the student outcomes they ultimately aim to achieve with their students. The study employs a cultural-historical continuum of scientific acts and reasoning, which represents the development of the AP Biology goal over time, to study gaps in their instructional goal. The study also analyzes the contradictions within their teaching practice and how teachers address those contradictions to shift their instructional practice and learn. The findings suggest that teachers have different interpretations of the AP Biology goals of science practice, placing their instructional goal at different points along the continuum. Based on the location of their instructional goal, different micro-communities of teachers exist along the continuum, comprised of teachers with a shared goal, language, and culture of their AP Biology teaching. The in-depth study of one teacher's AP Biology teaching, using a CHAT perspective, provides a means for studying the mechanisms that connect SCK to classroom actions and ultimately to instructional practice. CHAT also reveals the nature and importance of contradictions or cognitive dissonance in teacher learning and the types of support teachers need to

  3. Express

    Integrated Risk Information System (IRIS)

    Express ; CASRN 101200 - 48 - 0 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Effect

  4. What Are Youth Asking About Drugs? A Report of NIDA Drug Facts Chat Day.

    PubMed

    Morton, Cory M; Hoefinger, Heidi; Linn-Walton, Rebecca; Aikins, Ross; Falkin, Gregory P

    2015-01-01

    The current study analyzes a sample of questions about drugs asked online by youth who participated in the National Institute on Drug Abuse's (NIDA) "Drug Facts Chat Day." The types of drugs youth asked about were coded into 17 substance categories, and the topics they raised were coded into seven thematic categories. The top five queried drugs were marijuana (16.4%), alcohol (8.5%), tobacco (6%), cocaine (5.7), and pharmaceutical drugs (4.5%). The effects of drug use, experience of being high, the addictiveness of drugs, pharmacology, and drug sales were among the more common types of questions to emerge but varied depending on the substance. These findings show the types of information young people are seeking about drugs and have clear implications to inform youth drug education programs. PMID:26862133

  5. 2012 ARPA-E Energy Innovation Summit: Fireside Chat with Steven Chu and Bill Gates

    SciTech Connect

    Chu, Steven; Gates, Bill; Podesta, John

    2012-02-28

    The third annual ARPA-E Energy Innovation Summit was held in Washington D.C. in February, 2012. The event brought together key players from across the energy ecosystem - researchers, entrepreneurs, investors, corporate executives, and government officials - to share ideas for developing and deploying the next generation of energy technologies. This video captures a session called 'Fireside Chat' that featured Steven Chu, the Secretary of Energy, and Bill Gates, Chairman of Microsoft Corporation. The session is moderated by John Podesta, Chair of the Center for American Progress. Energy Secretary Steven Chu and Microsoft Founder and Chairman Bill Gates exchanged ideas about how small businesses and innovators can overcome the challenges that face many startups.

  6. What Makes Sports Fans Interactive? Identifying Factors Affecting Chat Interactions in Online Sports Viewing

    PubMed Central

    Yeo, Jaeryong; Lee, Juyeong

    2016-01-01

    Sports fans are able to watch games from many locations using TV services while interacting with other fans online. In this paper, we identify the factors that affect sports viewers’ online interactions. Using a large-scale dataset of more than 25 million chat messages from a popular social TV site for baseball, we extract various game-related factors, and investigate the relationships between these factors and fans’ interactions using a series of multiple regression analyses. As a result, we identify several factors that are significantly related to viewer interactions. In addition, we determine that the influence of these factors varies according to the user group; i.e., active vs. less active users, and loyal vs. non-loyal users. PMID:26849568

  7. 2012 ARPA-E Energy Innovation Summit: Fireside Chat with Steven Chu and Bill Gates

    ScienceCinema

    Chu, Steven (U.S. Department of Energy Secretary); Gates, Bill (Microsoft, Chairman); Podesta, John (Center for American Progress, Chair and Counselor)

    2012-03-21

    The third annual ARPA-E Energy Innovation Summit was held in Washington D.C. in February, 2012. The event brought together key players from across the energy ecosystem - researchers, entrepreneurs, investors, corporate executives, and government officials - to share ideas for developing and deploying the next generation of energy technologies. This video captures a session called 'Fireside Chat' that featured Steven Chu, the Secretary of Energy, and Bill Gates, Chairman of Microsoft Corporation. The session is moderated by John Podesta, Chair of the Center for American Progress. Energy Secretary Steven Chu and Microsoft Founder and Chairman Bill Gates exchanged ideas about how small businesses and innovators can overcome the challenges that face many startups.

  8. What Makes Sports Fans Interactive? Identifying Factors Affecting Chat Interactions in Online Sports Viewing.

    PubMed

    Ko, Minsam; Yeo, Jaeryong; Lee, Juyeong; Lee, Uichin; Jang, Young Jae

    2016-01-01

    Sports fans are able to watch games from many locations using TV services while interacting with other fans online. In this paper, we identify the factors that affect sports viewers' online interactions. Using a large-scale dataset of more than 25 million chat messages from a popular social TV site for baseball, we extract various game-related factors, and investigate the relationships between these factors and fans' interactions using a series of multiple regression analyses. As a result, we identify several factors that are significantly related to viewer interactions. In addition, we determine that the influence of these factors varies according to the user group; i.e., active vs. less active users, and loyal vs. non-loyal users. PMID:26849568

  9. On-Line "Chat Room" Tutorials—An Unusual Gender Bias in Computer Use

    NASA Astrophysics Data System (ADS)

    Kimbrough, Doris R.

    1999-09-01

    Research into gender bias in attitudes, access, and effectiveness associated with computers has produced conflicting results, resulting in conflicting opinions as to whether a technological gender gap favoring male students exists. No previous study, however, has ever demonstrated a preference for female use of a particular computer application. This work describes gender differences in the use of on-line ("chat room") tutorials by non-traditional chemistry students enrolled in distance learning sections of a general chemistry course. Higher percentages of female students participated in the on-line tutorials and they participated with greater frequency than male students. Furthermore, the correlation between frequency of participation and course performance was higher among the female students. Various explanations for this unusual gender bias are offered, and the conclusion that the diversity of computer applications available today requires that research into gender bias refrain from viewing the computer as a single entity is supported.

  10. From pen pals to chat rooms: the impact of social media on Middle Eastern Society.

    PubMed

    Hatfield, Elaine; Rapson, Richard L

    2015-01-01

    In this article, we will discuss what is known about a surprisingly popular phenomenon in the Middle East-the use of social media to communicate. We will begin with a discussion of what "social media" sites are (sites such as Facebook, Your Middle East, YouTube, Flickr, Muslima.com, chat rooms, and instant messaging) and point out how common they are in the Middle East. Next, we will discuss the reasons why men and women are currently using Internet and social media. Finally, we will discuss what impact social media have had on politics, political dissent, education, and men's and women's relationships-and the impact they might be expected to have in future years. Finally, we will focus on the impact of such media on men's and women's relationships-including cross-gender friendships, romantic relationships, and sexual relationships. PMID:26090303

  11. Protein-energy malnutrition is frequent and precocious in children with cri du chat syndrome.

    PubMed

    Lefranc, Violaine; de Luca, Arnaud; Hankard, Régis

    2016-05-01

    Protein-energy malnutrition (PEM) is poorly reported in cri du chat syndrome (CDCS) (OMIM #123450), a genetic disease that causes developmental delay and global growth retardation. The objective was to determine the nutritional status at different ages in children with CDCS and factors associated with PEM. A questionnaire focused on growth and nutritional care was sent to 190 families. Among 36 analyzable questionnaires, growth and nutritional indices compatible with PEM occurred in 47% of patients: 19% before 6 months of age, 24% between 6-12 months and 34% after 12 months. Eight patients received enteral feeding. Speech therapy for swallowing education was performed more often in malnourished children (63% vs. 22%, P < 0.02). PEM is frequent and occurs early in this disease, requiring closed nutritional monitoring. © 2016 Wiley Periodicals, Inc. PMID:26872355

  12. Repowering with an integrated gasification-cascaded humidified advanced turbine (IG-CHAT) cycle

    SciTech Connect

    Freier, M.D.; Goldstein, H.N.; Swensen, E.C.

    1998-12-31

    This paper presents the results of an evaluation of repowering a typical US based coal fired power plant with a combination of coal gasification and advanced turbine technologies. In this case, an oxygen blown, fixed bed gasifier (based on British Gas-Lurgi technology) generates clean, low temperature, medium Btu gas which is fired in an advanced type of power cycle; namely, the Cascaded Humidified Advanced Turbine, or CHAT cycle which is defined and described below. This conceptual site repowering follows the same methodology and uses the same design parameters as in a recent evaluation of plant repowering utilizing a broad suite of advanced technologies, many of which are currently being demonstrated in the Clean Coal Technology Demonstration Program.

  13. Structure and stability of online chat networks built on emotion-carrying links

    NASA Astrophysics Data System (ADS)

    Gligorijević, Vladimir; Skowron, Marcin; Tadić, Bosiljka

    2013-02-01

    High-resolution data of online chats are studied as a physical system in the laboratory in order to quantify collective behavior of users. Our analysis reveals strong regularities characteristic of natural systems with additional features. In particular, we find self-organized dynamics with long-range correlations in user actions and persistent associations among users that have the properties of a social network. Furthermore, the evolution of the graph and its architecture with specific k-core structure are shown to be related with the type and the emotion arousal of exchanged messages. Partitioning of the graph by deletion of the links which carry high arousal messages exhibits critical fluctuations at the percolation threshold.

  14. The molecular structure of ornithine acetyltransferase from Mycobacterium tuberculosis bound to ornithine, a competitive inhibitor.

    PubMed

    Sankaranarayanan, Ramasamy; Cherney, Maia M; Garen, Craig; Garen, Grace; Niu, Chunying; Yuan, Marshall; James, Michael N G

    2010-04-01

    Mycobacterium tuberculosis ornithine acetyltransferase (Mtb OAT; E.C. 2.3.1.35) is a key enzyme of the acetyl recycling pathway during arginine biosynthesis. It reversibly catalyzes the transfer of the acetyl group from N-acetylornithine (NAORN) to L-glutamate. Mtb OAT is a member of the N-terminal nucleophile fold family of enzymes. The crystal structures of Mtb OAT in native form and in its complex with ornithine (ORN) have been determined at 1.7 and 2.4 A resolutions, respectively. ORN is a competitive inhibitor of this enzyme against L-glutamate as substrate. Although the acyl-enzyme complex of Streptomyces clavuligerus ornithine acetyltransferase has been determined, ours is the first crystal structure to be reported of an ornithine acetyltransferase in complex with an inhibitor. ORN binding does not alter the structure of Mtb OAT globally. However, its presence stabilizes the three C-terminal residues that are disordered and not observed in the native structure. Also, stabilization of the C-terminal residues by ORN reduces the size of the active-site pocket volume in the structure of the ORN complex. The interactions of ORN and the protein residues of Mtb OAT unambiguously delineate the active-site residues of this enzyme in Mtb. Moreover, modeling studies carried out with NAORN based on the structure of the ORN-Mtb OAT complex reveal important interactions of the carbonyl oxygen of the acetyl group of NAORN with the main-chain nitrogen atom of Gly128 and with the side-chain oxygen of Thr127. These interactions likely help in the stabilization of oxyanion formation during enzymatic reaction and also will polarize the carbonyl carbon-oxygen bond, thereby enabling the side-chain atom O(gamma 1) of Thr200 to launch a nucleophilic attack on the carbonyl-carbon atom of the acetyl group of NAORN. PMID:20184895

  15. Activation Domain-Specific and General Transcription Stimulation by Native Histone Acetyltransferase Complexes

    PubMed Central

    Ikeda, Keiko; Steger, David J.; Eberharter, Anton; Workman, Jerry L.

    1999-01-01

    Recent progress in identifying the catalytic subunits of histone acetyltransferase (HAT) complexes has implicated histone acetylation in the regulation of transcription. Here, we have analyzed the function of two native yeast HAT complexes, SAGA (Spt-Ada-Gcn5 Acetyltransferase) and NuA4 (nucleosome acetyltransferase of H4), in activating transcription from preassembled nucleosomal array templates in vitro. Each complex was tested for the ability to enhance transcription driven by GAL4 derivatives containing either acidic, glutamine-rich, or proline-rich activation domains. On nucleosomal array templates, the SAGA complex selectively stimulates transcription driven by the VP16 acidic activation domain in an acetyl coenzyme A-dependent manner. In contrast, the NuA4 complex facilitates transcription mediated by any of the activation domains tested if allowed to preacetylate the nucleosomal template, indicating a general stimulatory effect of histone H4 acetylation. However, when the extent of acetylation by NuA4 is limited, the complex also preferentially stimulates VP16-driven transcription. SAGA and NuA4 interact directly with the VP16 activation domain but not with a glutamine-rich or proline-rich activation domain. These data suggest that recruitment of the SAGA and NuA4 HAT complexes by the VP16 activation domain contributes to HAT-dependent activation. In addition, extensive H4/H2B acetylation by NuA4 leads to a general activation of transcription, which is independent of activator-NuA4 interactions. PMID:9858608

  16. New substrate analogues of human serotonin N-acetyltransferase produce in situ specific and potent inhibitors.

    PubMed

    Ferry, Gilles; Ubeaud, Caroline; Mozo, Julien; Péan, Christophe; Hennig, Philippe; Rodriguez, Marianne; Scoul, Catherine; Bonnaud, Anne; Nosjean, Olivier; Galizzi, Jean-Pierre; Delagrange, Philippe; Renard, Pierre; Volland, Jean-Paul; Yous, Said; Lesieur, Daniel; Boutin, Jean A

    2004-01-01

    Melatonin is synthesized by an enzymatic pathway, in which arylalkylamine (serotonin) N-acetyltransferase catalyzes the rate-limiting step. A previous study reported the discovery of bromoacetyltryptamine (BAT), a new type of inhibitor of this enzyme. This compound is the precursor of a potent bifunctional inhibitor (analogue of the transition state), capable of interfering with both the substrate and the cosubstrate binding sites. This inhibitor is biosynthesized by the enzyme itself in the presence of free coenzyme A. In the present report, we describe the potency of new N-halogenoacetyl derivatives leading to a strong in situ inhibition of serotonin N-acetyltransferase. The new concept behind the mechanism of action of these precursors was studied by following the biosynthesis of the inhibitor from tritiated-BAT in a living cell. The fate of tritiated-phenylethylamine (PEA), a natural substrate of the enzyme, in the presence or absence of [(3)H]BAT was also followed, leading to their incorporation into the reaction product or the inhibitor (N-acetyl[(3)H]PEA and coenzyme A-S[(3)H]acetyltryptamine, respectively). The biosynthesis of this bifunctional inhibitor derived from BAT was also followed by nuclear magnetic resonance during its catalytic production by the pure enzyme. In a similar manner we studied the production of another inhibitor generated from N-[2-(7-hydroxynaphth-1-yl)ethyl]bromoacetamide. New derivatives were also screened for their capacity to inhibit a purified enzyme, in addition to enzyme overexpressed in a cellular model. Some of these compounds proved to be extremely potent, with IC(50)s of approximately 30 nM. As these compounds, by definition, closely resemble the natural substrates of arylalkylamine N-acetyltransferase, we also show that they are potent ligands at the melatonin receptors. Nevertheless, these inhibitors form a series of pharmacological tools that could be used to understand more closely the inhibition of pineal melatonin

  17. Evaluation of CancerChatCanada: a program of online support for Canadians affected by cancer

    PubMed Central

    Stephen, J.; Rojubally, A.; MacGregor, K.; McLeod, D.; Speca, M.; Taylor–Brown, J.; Fergus, K.; Collie, K.; Turner, J.; Sellick, S.; Mackenzie, G.

    2013-01-01

    Background Professional-led cancer support groups can improve quality of life and address unmet needs, but most Canadians affected by cancer do not have access to or do not make use of cancer support groups. A collaborative interdisciplinary team developed, operated, and evaluated Internet-based, professional-led, live-chat support groups (osgs) for cancer patients, caregivers, and survivors across Canada. Objective Our study aimed to report participant and participation characteristics in the pan-Canadian initiative known as CancerChatCanada, and to understand participant perspectives about the quality of communication and professional facilitation, overall satisfaction, and psychosocial benefits and outcomes. Methods Participants in osgs provided informed consent. Participant and participation characteristics were gathered from program data collection tools and are described using frequencies, means, and chi-squares. Patient, survivor, and caregiver perspectives were derived from 102 telephone interviews conducted after osg completion and subjected to a directed qualitative content analysis. Results The 55 professional-led osgs enrolled 351 participants from 9 provinces. More than half the participants came from rural or semirural areas, and more than 84% had no received previous cancer support. The attendance rate was 75%, the dropout rate was 26%, and 80% of participants were satisfied or very satisfied. The convenience and privacy of osgs were benefits. Meaningful communication about important and difficult topics, kinship and bonding with others, and improved mood and self-care were perceived outcomes. Conclusions Our results demonstrate that this collaborative initiative was successful in increasing reach and access, and that pan-Canadian, professional-led osgs provide psychosocial benefit to underserved and burdened cancer patients, survivors, and family caregivers. PMID:23443892

  18. Analysis of Streptococcus pyogenes promoters by using novel Tn916-based shuttle vectors for the construction of transcriptional fusions to chloramphenicol acetyltransferase.

    PubMed Central

    Geist, R T; Okada, N; Caparon, M G

    1993-01-01

    We have developed a series of shuttle vectors based on the conjugative transposon Tn916 that have been designed for the analysis of transcriptional regulation in Streptococcus pyogenes and other gram-positive bacteria. Designated the pVIT vectors (vectors for integration into Tn916), the vectors are small, stable plasmids in Escherichia coli to facilitate the fusion of promoters from cloned S. pyogenes genes to a promoterless gene which encodes chloramphenicol acetyltransferase. The vectors each contain one or more small regions of Tn916 to direct the integration of the transcriptional fusion into the transposon via homologous recombination following transformation of S. pyogenes or other suitable gram-positive hosts. Integration can be monitored by the inactivation or replacement of an antibiotic resistance determinant in modified derivatives of Tn916. Promoter activity can then be quantitated by the determination of chloramphenicol acetyltransferase-specific activity. In addition, since integration is into loci that do not disrupt the conjugative transpositional functions of Tn916, the vectors are useful for analysis of regulation in strains that are difficult or impossible to transform and can be introduced into these strains by conjugation following transformation of an intermediate host. The promoters for the genes which encode both the M protein and protein F of S. pyogenes were active in pVIT vectors, as was the region which controls transcription of mry, a trans-acting positive regulator of M protein expression. However, neither of the two characterized promoters for mry demonstrated activity when independently analyzed in pVIT-generated partial diploid strains, suggesting that regulation of mry is more complex than predicted by current models. The broad host range of Tn916 should make the pVIT vectors useful for analysis of regulation in numerous other bacterial species. PMID:8244925

  19. The Methionine Transamination Pathway Controls Hepatic Glucose Metabolism through Regulation of the GCN5 Acetyltransferase and the PGC-1α Transcriptional Coactivator.

    PubMed

    Tavares, Clint D J; Sharabi, Kfir; Dominy, John E; Lee, Yoonjin; Isasa, Marta; Orozco, Jose M; Jedrychowski, Mark P; Kamenecka, Theodore M; Griffin, Patrick R; Gygi, Steven P; Puigserver, Pere

    2016-05-13

    Methionine is an essential sulfur amino acid that is engaged in key cellular functions such as protein synthesis and is a precursor for critical metabolites involved in maintaining cellular homeostasis. In mammals, in response to nutrient conditions, the liver plays a significant role in regulating methionine concentrations by altering its flux through the transmethylation, transsulfuration, and transamination metabolic pathways. A comprehensive understanding of how hepatic methionine metabolism intersects with other regulatory nutrient signaling and transcriptional events is, however, lacking. Here, we show that methionine and derived-sulfur metabolites in the transamination pathway activate the GCN5 acetyltransferase promoting acetylation of the transcriptional coactivator PGC-1α to control hepatic gluconeogenesis. Methionine was the only essential amino acid that rapidly induced PGC-1α acetylation through activating the GCN5 acetyltransferase. Experiments employing metabolic pathway intermediates revealed that methionine transamination, and not the transmethylation or transsulfuration pathways, contributed to methionine-induced PGC-1α acetylation. Moreover, aminooxyacetic acid, a transaminase inhibitor, was able to potently suppress PGC-1α acetylation stimulated by methionine, which was accompanied by predicted alterations in PGC-1α-mediated gluconeogenic gene expression and glucose production in primary murine hepatocytes. Methionine administration in mice likewise induced hepatic PGC-1α acetylation, suppressed the gluconeogenic gene program, and lowered glycemia, indicating that a similar phenomenon occurs in vivo These results highlight a communication between methionine metabolism and PGC-1α-mediated hepatic gluconeogenesis, suggesting that influencing methionine metabolic flux has the potential to be therapeutically exploited for diabetes treatment. PMID:27022023

  20. Comprehensive analysis of interacting proteins and genome-wide location studies of the Sas3-dependent NuA3 histone acetyltransferase complex

    PubMed Central

    Vicente-Muñoz, Sara; Romero, Paco; Magraner-Pardo, Lorena; Martinez-Jimenez, Celia P.; Tordera, Vicente; Pamblanco, Mercè

    2014-01-01

    Histone acetylation affects several aspects of gene regulation, from chromatin remodelling to gene expression, by modulating the interplay between chromatin and key transcriptional regulators. The exact molecular mechanism underlying acetylation patterns and crosstalk with other epigenetic modifications requires further investigation. In budding yeast, these epigenetic markers are produced partly by histone acetyltransferase enzymes, which act as multi-protein complexes. The Sas3-dependent NuA3 complex has received less attention than other histone acetyltransferases (HAT), such as Gcn5-dependent complexes. Here, we report our analysis of Sas3p-interacting proteins using tandem affinity purification (TAP), coupled with mass spectrometry. This analysis revealed Pdp3p, a recently described component of NuA3, to be one of the most abundant Sas3p-interacting proteins. The PDP3 gene, was TAP-tagged and protein complex purification confirmed that Pdp3p co-purified with the NuA3 protein complex, histones, and several transcription-related and chromatin remodelling proteins. Our results also revealed that the protein complexes associated with Sas3p presented HAT activity even in the absence of Gcn5p and vice versa. We also provide evidence that Sas3p cannot substitute Gcn5p in acetylation of lysine 9 in histone H3 in vivo. Genome-wide occupancy of Sas3p using ChIP-on-chip tiled microarrays showed that Sas3p was located preferentially within the 5′-half of the coding regions of target genes, indicating its probable involvement in the transcriptional elongation process. Hence, this work further characterises the function and regulation of the NuA3 complex by identifying novel post-translational modifications in Pdp3p, additional Pdp3p-co-purifying chromatin regulatory proteins involved in chromatin-modifying complex dynamics and gene regulation, and a subset of genes whose transcriptional elongation is controlled by this complex. PMID:25473596

  1. Crystallization of ornithine acetyltransferase from yeast by counter-diffusion and preliminary X-ray study

    PubMed Central

    Maes, Dominique; Crabeel, Marjolaine; Van de Weerdt, Cécile; Martial, Joseph; Peeters, Eveline; Charlier, Daniël; Decanniere, Klaas; Vanhee, Celine; Wyns, Lode; Zegers, Ingrid

    2006-01-01

    A study is presented on the crystallization of ornithine acetyltransferase from yeast, which catalyzes the fifth step in microbial arginine synthesis. The use of the counter-diffusion technique removes the disorder present in one dimension in crystals grown by either the batch or hanging-drop techniques. This makes the difference between useless crystals and crystals that allow successful determination of the structure of the protein. The crystals belong to space group P4, with unit-cell parameters a = b = 66.98, c = 427.09 Å, and a data set was collected to 2.76 Å. PMID:17142921

  2. Choline Acetyltransferase Activity in Striatum of Neonatal Rats Increased by Nerve Growth Factor

    NASA Astrophysics Data System (ADS)

    Mobley, William C.; Rutkowski, J. Lynn; Tennekoon, Gihan I.; Buchanan, Karen; Johnston, Michael V.

    1985-07-01

    Some neurodegenerative disorders may be caused by abnormal synthesis or utilization of trophic molecules required to support neuronal survival. A test of this hypothesis requires that trophic agents specific for the affected neurons be identified. Cholinergic neurons in the corpus striatum of neonatal rats were found to respond to intracerebroventricular administration of nerve growth factor with prominent, dose-dependent, selective increases in choline acetyltransferase activity. Cholinergic neurons in the basal forebrain also respond to nerve growth factor in this way. These actions of nerve growth factor may indicate its involvement in the normal function of forebrain cholinergic neurons as well as in neurodegenerative disorders involving such cells.

  3. Synthesis of 4'-aminopantetheine and derivatives to probe aminoglycoside N-6'-acetyltransferase.

    PubMed

    Yan, Xuxu; Akinnusi, T Olukayode; Larsen, Aaron T; Auclair, Karine

    2011-03-01

    A convenient synthesis of 4'-aminopantetheine from commercial D-pantethine is reported. The amino group was introduced by reductive amination in order to avoid substitution at a sterically congested position. Derivatives of 4'-aminopantetheine were also prepared to evaluate the effect of O-to-N substitution on inhibitors of the resistance-causing enzyme aminoglycoside N-6'-acetyltransferase. The biological results combined with docking studies indicate that in spite of its reported unusual flexibility and ability to adopt different folds, this enzyme is highly specific for AcCoA. PMID:21225062

  4. Synthesis of 4′-aminopantetheine and derivatives to probe aminoglycoside N-6′-acetyltransferase

    PubMed Central

    Yan, Xuxu; Akinnusi, T. Olukayode; Larsen, Aaron T.; Auclair, Karine

    2011-01-01

    Summary A convenient synthesis of 4′-aminopantetheine from commercial D-pantethine is reported. The amino group was introduced by reductive amination in order to avoid substitution at a sterically congested position. Derivatives of 4′-aminopantetheine were also prepared to evaluate the effect of O-to-N substitution on inhibitors of the resistance-causing enzyme aminoglycoside N-6′-acetyltransferase. The biological results combined with docking studies indicate that in spite of its reported unusual flexibility and ability to adopt different folds, this enzyme is highly specific for AcCoA. PMID:21225062

  5. One-step purification of phosphinothricin acetyltransferase using reactive dye-affinity chromatography.

    PubMed

    Wang, Cunxi; Lee, Thomas C; Crowley, Kathleen S; Bell, Erin

    2015-01-01

    Reactive dye purification is an affinity purification technique offering unique selectivity and high purification potential. Historically, purification of phosphinothricin acetyltransferase (PAT) has involved several steps of precipitation and column chromatography. Here, we describe a novel purification method that is simple, time-saving, inexpensive, and reproducible. The novel method employs a single chromatography step using a reactive dye resin, Reactive brown 10-agarose. Reactive brown 10 preferentially binds the PAT protein, which can then be specifically released by one of its substrates, acetyl-CoA. Using Reactive brown 10-agarose, PAT protein can be purified to homogeneity from E. coli or plant tissue with high recovery efficiency. PMID:25749943

  6. Cinnamoyl compounds as simple molecules that inhibit p300 histone acetyltransferase.

    PubMed

    Costi, Roberta; Di Santo, Roberto; Artico, Marino; Miele, Gaetano; Valentini, Paola; Novellino, Ettore; Cereseto, Anna

    2007-04-19

    Cinnamoly compounds 1a-c and 2a-d were designed, synthesized, and in vitro tested as p300 inhibitors. At different degrees, all tested compounds were proven to inactivate p300, particularly, derivative 2c was the most active inhibitor, also showing high specificity for p300 as compared to other histone acetyltransferases. Most notably, 2c showed anti-acetylase activity in mammalian cells. These compounds represent a new class of synthetic inhibitors of p300, characterized by simple chemical structures. PMID:17348637

  7. Biochemical Analysis and Structure Determination of Bacterial Acetyltransferases Responsible for the Biosynthesis of UDP-N,N′-Diacetylbacillosamine*

    PubMed Central

    Morrison, Michael J.; Imperiali, Barbara

    2013-01-01

    UDP-N,N′-diacetylbacillosamine (UDP-diNAcBac) is a unique carbohydrate produced by a number of bacterial species and has been implicated in pathogenesis. The terminal step in the formation of this important bacterial sugar is catalyzed by an acetyl-CoA (AcCoA)-dependent acetyltransferase in both N- and O-linked protein glycosylation pathways. This bacterial acetyltransferase is a member of the left-handed β-helix family and forms a homotrimer as the functional unit. Whereas previous endeavors have focused on the Campylobacter jejuni acetyltransferase (PglD) from the N-linked glycosylation pathway, structural characterization of the homologous enzymes in the O-linked glycosylation pathways is lacking. Herein, we present the apo-crystal structures of the acetyltransferase domain (ATD) from the bifunctional enzyme PglB (Neisseria gonorrhoeae) and the full-length acetyltransferase WeeI (Acinetobacter baumannii). Additionally, a PglB-ATD structure was solved in complex with AcCoA. Surprisingly, this structure reveals a contrasting binding mechanism for this substrate when compared with the AcCoA-bound PglD structure. A comparison between these findings and the previously solved PglD crystal structures illustrates a dichotomy among N- and O-linked glycosylation pathway enzymes. Based upon these structures, key residues in the UDP-4-amino and AcCoA binding pockets were mutated to determine their effect on binding and catalysis in PglD, PglB-ATD, and WeeI. Last, a phylogenetic analysis of the aforementioned acetyltransferases was employed to illuminate the diversity among N- and O-linked glycosylation pathway enzymes. PMID:24064219

  8. Biochemical analysis and structure determination of bacterial acetyltransferases responsible for the biosynthesis of UDP-N,N'-diacetylbacillosamine.

    PubMed

    Morrison, Michael J; Imperiali, Barbara

    2013-11-01

    UDP-N,N'-diacetylbacillosamine (UDP-diNAcBac) is a unique carbohydrate produced by a number of bacterial species and has been implicated in pathogenesis. The terminal step in the formation of this important bacterial sugar is catalyzed by an acetyl-CoA (AcCoA)-dependent acetyltransferase in both N- and O-linked protein glycosylation pathways. This bacterial acetyltransferase is a member of the left-handed β-helix family and forms a homotrimer as the functional unit. Whereas previous endeavors have focused on the Campylobacter jejuni acetyltransferase (PglD) from the N-linked glycosylation pathway, structural characterization of the homologous enzymes in the O-linked glycosylation pathways is lacking. Herein, we present the apo-crystal structures of the acetyltransferase domain (ATD) from the bifunctional enzyme PglB (Neisseria gonorrhoeae) and the full-length acetyltransferase WeeI (Acinetobacter baumannii). Additionally, a PglB-ATD structure was solved in complex with AcCoA. Surprisingly, this structure reveals a contrasting binding mechanism for this substrate when compared with the AcCoA-bound PglD structure. A comparison between these findings and the previously solved PglD crystal structures illustrates a dichotomy among N- and O-linked glycosylation pathway enzymes. Based upon these structures, key residues in the UDP-4-amino and AcCoA binding pockets were mutated to determine their effect on binding and catalysis in PglD, PglB-ATD, and WeeI. Last, a phylogenetic analysis of the aforementioned acetyltransferases was employed to illuminate the diversity among N- and O-linked glycosylation pathway enzymes. PMID:24064219

  9. Purification, crystallization and preliminary X-ray characterization of Bacillus cereus arylamine N-acetyltransferase 3 [(BACCR)NAT3].

    PubMed

    Kubiak, Xavier; Pluvinage, Benjamin; Li de la Sierra-Gallay, Inès; Weber, Patrick; Haouz, Ahmed; Dupret, Jean-Marie; Rodrigues-Lima, Fernando

    2012-02-01

    Arylamine N-acetyltransferases (NATs) are xenobiotic metabolizing enzymes (XMEs) that catalyze the acetylation of arylamines. All functional NATs described to date possess a strictly conserved Cys-His-Asp catalytic triad. Here, the purification, crystallization and preliminary X-ray characterization of Bacillus cereus arylamine N-acetyltransferase 3 [(BACCR)NAT3], a putative NAT isoenzyme that possesses a unique catalytic triad containing a glutamate residue, is reported. The crystal diffracted to 2.42 Å resolution and belonged to the monoclinic space group C121, with unit-cell parameters a = 90.44, b = 44.52, c = 132.98 Å, β = 103.8°. PMID:22297998

  10. Arylamine N-acetyltransferase (NAT2) mutations and their allelic linkage in unrelated caucasian individuals: Correlation with phenotypic activity

    SciTech Connect

    Cascorbi, I.; Drakoulis, N.; Brockmoeller, J.

    1995-09-01

    The polymorphic arylamine N-acetyltransferase (NAT2; EC2.3.1.5) is supposed to be a susceptibility factor for several drug side effects and certain malignancies. A group of 844 unrelated German subjects was genotyped for their acetylation type, and 563 of them were also phenotyped. Seven mutations of the NAT2 gene were evaluated by allele-specific PCR (mutation 341C to T) and PCR-RFLP for mutations at nt positions 191, 282, 481, 590, 803, and 857. From the mutation pattern eight different alleles, including the wild type coding for rapid acetylation and seven alleles coding for slow phenotype, were determined. Four hundred ninety-seven subjects had a genotype of slow acetylation (58.9%; 95% confidence limits 55.5%-62.2%). Phenotypic acetylation capacity was expressed as the ratio of 5-acetylamino-6-formylamino-3-methyluracil and 1-methylxanthine in urine after caffeine intake. Some 6.7% of the cases deviated in genotype and phenotype, but sequencing DNA of these probands revealed no new mutations. Furthermore, linkage pattern of the mutations was always confirmed, as tested in 533 subjects. In vivo acetylation capacity of homozygous wild-type subjects (NAT2{sup *}4/{sup *}4) was significantly higher than in heterozygous genotypes (P = .001). All mutant alleles showed low in vivo acetylation capacities, including the previously not-yet-defined alleles {sup *}5A, {sup *}5C, and {sup *}13. Moreover, distinct slow genotypes differed significantly among each other, as reflected in lower acetylation capacity of {sup *}6A, {sup *}7B, and {sup *}13 alleles than the group of {sup *}5 alleles. The study demonstrated differential phenotypic activity of various NAT2 genes and gives a solid basis for clinical and molecular-epidemiological investigations. 34 refs., 4 figs., 7 tabs.

  11. Microscopy-based Saccharomyces cerevisiae complementation model reveals functional conservation and redundancy of N-terminal acetyltransferases.

    PubMed

    Osberg, Camilla; Aksnes, Henriette; Ninzima, Sandra; Marie, Michaël; Arnesen, Thomas

    2016-01-01

    N-terminal acetylation is a highly abundant protein modification catalyzed by N-terminal acetyltransferases (NATs) NatA-NatG. The Saccharomyces cerevisiae protein Arl3 depends on interaction with Sys1 for its localization to the Golgi and this targeting strictly requires NatC-mediated N-terminal acetylation of Arl3. We utilized the Arl3 acetylation-dependent localization phenotype as a model system for assessing the functional conservation and in vivo redundancy of several human NATs. The catalytic subunit of human NatC, hNaa30 (Mak3), restored Arl3 localization in the absence of yNaa30, but only in the presence of either yeast or human Naa35 subunit (Mak10). In contrast, hNaa35 was not able to replace its yeast orthologue without the co-expression of hNaa30, suggesting co-evolution of the two NatC subunits. The most recently discovered and organellar human NAT, NatF/Naa60, restored the Golgi localization of Arl3 in the absence of yNaa30. Interestingly, this was also true for hNaa60 lacking its membrane-binding domain whereas hNaa50 did not complement NatC function. This in vivo redundancy reflects NatC and NatF´s overlapping in vitro substrate specificities. The yeast model presented here provides a robust and rapid readout of NatC and NatF activity in vivo, and revealed evolutionary conservation of the NatC complex and redundancy between NatC and NatF. PMID:27555049

  12. Identification and functional characterization of novel polymorphisms associated with the genes for arylamine N-acetyltransferases in mice.

    PubMed

    Boukouvala, Sotiria; Price, Naomi; Sim, Edith

    2002-07-01

    Arylamine N-acetyltransferase (NAT) polymorphism in humans has been associated with variation in susceptibility to drug toxicity and cancer. In mice, three NAT isoenzymes are encoded by Nat1, Nat2 and Nat3 genes. Only Nat2 has been shown previously to be polymorphic, a single nucleotide substitution causing the slow acetylator phenotype in the A/J strain. We sequenced the Nat genes from inbred (CBA and 129/Ola), outbred (PO and TO) and wild-derived inbred (Mus spretus and Mus musculus castaneus) mouse strains and report polymorphism in all three Nat genes of M. spretus and in Nat2 and Nat3 genes of M. m. castaneus. Enzymatic activity assays using liver homogenates demonstrated that M. m. castaneus is a 'fast' and M. spretus a 'slow' acetylator. Western blot analysis indicated that hepatic NAT2 protein is less abundant in M. spretus than M. m. castaneus. The new allozymes were expressed in a mammalian cell line and NAT enzymatic activity was measured with a series of substrates. NAT1 and NAT2 isoenzymes of M. m. castaneus exhibited a higher rate of acetylation, compared with those of M. spretus. Activity of the NAT3 allozymes was hardly detectable, although the Nat3 gene does appear to be transcribed, since mRNA was detected by RT-PCR in the spleen. Additional polymorphisms, useful for Nat-related genetic studies, have been identified between BALB/c, C57Bl/6J, A/J, 129/Ola, CBA, PO, TO, M. m. castaneus and M. spretus strains in four microsatellite repeats located close to the Nat genes. PMID:12142728

  13. Cloning and characterization of the serotonin N-acetyltransferase-2 gene (SNAT2) in rice (Oryza sativa).

    PubMed

    Byeon, Yeong; Lee, Hyoung Yool; Back, Kyoungwhan

    2016-09-01

    The penultimate enzyme in melatonin synthesis is serotonin N-acetyltransferase (SNAT), which exists as a single copy in mammals and plants. Our recent studies of the Arabidopsis snat-knockout mutant and SNAT RNAi rice (Oryza sativa) plants predicted the presence of at least one other SNAT isogene in plants; that is, the snat-knockout mutant of Arabidopsis and the SNAT RNAi rice plants still produced melatonin, even in the absence or the suppression of SNAT expression. Here, we report a molecular cloning of an SNAT isogene (OsSNAT2) from rice. The mature amino acid sequences of SNAT proteins indicated that OsSNAT2 and OsSNAT1 proteins had 39% identity values and 60% similarity. The Km and Vmax values of the purified recombinant OsSNAT2 were 371 μm and 4700 pmol/min/mg protein, respectively; the enzyme's optimal activity temperature was 45°C. Confocal microscopy showed that the OsSNAT2 protein was localized to both the cytoplasm and chloroplasts. The in vitro enzyme activity of OsSNAT2 was severely inhibited by melatonin, but the activities of sheep SNAT (OaSNAT) and rice OsSNAT1 proteins were not. The enzyme activity of OsSNAT2 was threefold higher than that of OsSNAT1, but 232-fold lower than that of OaSNAT. The OsSNAT1 and OsSNAT2 transcripts were similarly suppressed in rice leaves during the melatonin induction after cadmium treatment. Phylogenetic analyses indicated that OsSNAT1 and OsSNAT2 are distantly related, suggesting that they evolved independently from Cyanobacteria prior to the endosymbiosis event. PMID:27121038

  14. Microscopy-based Saccharomyces cerevisiae complementation model reveals functional conservation and redundancy of N-terminal acetyltransferases

    PubMed Central

    Osberg, Camilla; Aksnes, Henriette; Ninzima, Sandra; Marie, Michaël; Arnesen, Thomas

    2016-01-01

    N-terminal acetylation is a highly abundant protein modification catalyzed by N-terminal acetyltransferases (NATs) NatA-NatG. The Saccharomyces cerevisiae protein Arl3 depends on interaction with Sys1 for its localization to the Golgi and this targeting strictly requires NatC-mediated N-terminal acetylation of Arl3. We utilized the Arl3 acetylation-dependent localization phenotype as a model system for assessing the functional conservation and in vivo redundancy of several human NATs. The catalytic subunit of human NatC, hNaa30 (Mak3), restored Arl3 localization in the absence of yNaa30, but only in the presence of either yeast or human Naa35 subunit (Mak10). In contrast, hNaa35 was not able to replace its yeast orthologue without the co-expression of hNaa30, suggesting co-evolution of the two NatC subunits. The most recently discovered and organellar human NAT, NatF/Naa60, restored the Golgi localization of Arl3 in the absence of yNaa30. Interestingly, this was also true for hNaa60 lacking its membrane-binding domain whereas hNaa50 did not complement NatC function. This in vivo redundancy reflects NatC and NatF´s overlapping in vitro substrate specificities. The yeast model presented here provides a robust and rapid readout of NatC and NatF activity in vivo, and revealed evolutionary conservation of the NatC complex and redundancy between NatC and NatF. PMID:27555049

  15. Intracellular localization of α-tubulin acetyltransferase ATAT1 in rat ciliated cells.

    PubMed

    Nakakura, Takashi; Suzuki, Takeshi; Nemoto, Takahiro; Tanaka, Hideyuki; Asano-Hoshino, Anshin; Arisawa, Kenjiro; Nishijima, Yoshimi; Kiuchi, Yoshiko; Hagiwara, Haruo

    2016-09-01

    Cilia are microtubule-based hair-like organelles on basal bodies located beneath the cell membrane in various tissues of multicellular animals, and are usually classified into motile cilia and primary cilia. Microtubules are assembled from the heterodimers of α- and β-tubulin. The lysine residue at position 40 (K40) of α-tubulin is an important site for acetylation, and this site is acetylated in the cilium. α-Tubulin N-acetyltransferase 1 (ATAT1) is an acetyltransferase specific to the K40 residue of α-tubulin; however, its intracellular distribution in mammalian tissues remains unclear. In this study, we analyzed ATAT1 localization in rat trachea, oviduct, kidney, retina, testis and the third ventricle of the brain by immunohistochemical techniques using a specific antibody against ATAT1. ATAT1 was distributed to the motile cilia of multiciliated cells of the trachea, third ventricle of the brain and oviduct, and in the primary cilia of the renal medullary collecting duct. ATAT1 also localized to the primary cilia, inner and outer segments of retinal photoreceptor cells, and at the Golgi apparatus of spermatocytes and spermatids of testis. These results indicated that α-tubulin acetylation by ATAT1 at distinct subcellular positions may influence the functional regulation of microtubules and cilia in a variety of ciliated cells. PMID:26700226

  16. Structure and Functional Diversity of GCN5-Related N-Acetyltransferases (GNAT).

    PubMed

    Salah Ud-Din, Abu Iftiaf Md; Tikhomirova, Alexandra; Roujeinikova, Anna

    2016-01-01

    General control non-repressible 5 (GCN5)-related N-acetyltransferases (GNAT) catalyze the transfer of an acyl moiety from acyl coenzyme A (acyl-CoA) to a diverse group of substrates and are widely distributed in all domains of life. This review of the currently available data acquired on GNAT enzymes by a combination of structural, mutagenesis and kinetic methods summarizes the key similarities and differences between several distinctly different families within the GNAT superfamily, with an emphasis on the mechanistic insights obtained from the analysis of the complexes with substrates or inhibitors. It discusses the structural basis for the common acetyltransferase mechanism, outlines the factors important for the substrate recognition, and describes the mechanism of action of inhibitors of these enzymes. It is anticipated that understanding of the structural basis behind the reaction and substrate specificity of the enzymes from this superfamily can be exploited in the development of novel therapeutics to treat human diseases and combat emerging multidrug-resistant microbial infections. PMID:27367672

  17. Purification and characterization of glutamate N-acetyltransferase involved in citrulline accumulation in wild watermelon.

    PubMed

    Takahara, Kentaro; Akashi, Kinya; Yokota, Akiho

    2005-10-01

    Citrulline is an efficient hydroxyl radical scavenger that can accumulate at concentrations of up to 30 mm in the leaves of wild watermelon during drought in the presence of strong light; however, the mechanism of this accumulation remains unclear. In this study, we characterized wild watermelon glutamate N-acetyltransferase (CLGAT) that catalyses the transacetylation reaction between acetylornithine and glutamate to form acetylglutamate and ornithine, thereby functioning in the first and fifth steps in citrulline biosynthesis. CLGAT enzyme purified 7000-fold from leaves was composed of two subunits with different N-terminal amino acid sequences. Analysis of the corresponding cDNA revealed that these two subunits have molecular masses of 21.3 and 23.5 kDa and are derived from a single precursor polypeptide, suggesting that the CLGAT precursor is cleaved autocatalytically at the conserved ATML motif, as in other glutamate N-acetyltransferases of microorganisms. A green fluorescence protein assay revealed that the first 26-amino acid sequence at the N-terminus of the precursor functions as a chloroplast transit peptide. The CLGAT exhibited thermostability up to 70 degrees C, suggesting an increase in enzyme activity under high leaf temperature conditions during drought/strong-light stresses. Moreover, CLGAT was not inhibited by citrulline or arginine at physiologically relevant high concentrations. These findings suggest that CLGAT can effectively participate in the biosynthesis of citrulline in wild watermelon leaves during drought/strong-light stress. PMID:16218965

  18. Studying aminoglycoside modification by the acetyltransferase class of resistance-causing enzymes via microarray

    PubMed Central

    Barrett, Olivia J.; Pushechnikov, Alexei; Wu, Meilan; Disney, Matthew D.

    2008-01-01

    Aminoglycosides are broad-spectrum antibacterials to which some bacteria have acquired resistance. The most common mode of resistance to aminoglycosides is enzymatic modification of the drug by different classes of enzymes including acetyltransferases (AAC’s). Thus, the modification of aminoglycosides by AAC(2’) from Mycobacterium tuberculosis and AAC(3) from Escherichia coli was studied using aminoglycoside microarrays. Results show that both enzymes modify their substrates displayed on an array surface in a manner that mimics their relative levels of modification in solution. Because aminoglycosides that are modified by resistance-causing enzymes have reduced affinities for binding their therapeutic target, the bacterial rRNA aminoacyl-tRNA site (A-site), arrays were probed for binding to a fluorescently labeled oligonucleotide mimic of the A-site after modification. A decrease in binding was observed when aminoglycosides were modified by AAC(3). In contrast, a decrease in binding of the A-site is not observed when aminoglycosides are modified by AAC(2’). Interestingly, these effects mirror the biological functions of these enzymes: the AAC(3) used in this study is known to confer aminoglycoside resistance while the AAC(2’) is chromosomally encoded and unlikely to play a role in resistance. These studies lay a direct foundation for studying resistance to aminoglycosides and can also have more broad applications in identifying and studying non-aminoglycoside carbohydrates or proteins as substrates for acetyltransferase enzymes. PMID:18774127

  19. Crystal structure of bacillus subtilis YdaF protein : a putative ribosomal N-acetyltransferase.

    SciTech Connect

    Brunzelle, J. S.; Wu, R.; Korolev, S. V.; Collart, F. R.; Joachimiak, A.; Anderson, W. F.; Biosciences Division; Northwestern Univ.; Saint Louis Univ. School of Medicine

    2004-12-01

    Comparative sequence analysis suggests that the ydaF gene encodes a protein (YdaF) that functions as an N-acetyltransferase, more specifically, a ribosomal N-acetyltransferase. Sequence analysis using basic local alignment search tool (BLAST) suggests that YdaF belongs to a large family of proteins (199 proteins found in 88 unique species of bacteria, archaea, and eukaryotes). YdaF also belongs to the COG1670, which includes the Escherichia coli RimL protein that is known to acetylate ribosomal protein L12. N-acetylation (NAT) has been found in all kingdoms. NAT enzymes catalyze the transfer of an acetyl group from acetyl-CoA (AcCoA) to a primary amino group. For example, NATs can acetylate the N-terminal {alpha}-amino group, the {epsilon}-amino group of lysine residues, aminoglycoside antibiotics, spermine/speridine, or arylalkylamines such as serotonin. The crystal structure of the alleged ribosomal NAT protein, YdaF, from Bacillus subtilis presented here was determined as a part of the Midwest Center for Structural Genomics. The structure maintains the conserved tertiary structure of other known NATs and a high sequence similarity in the presumed AcCoA binding pocket in spite of a very low overall level of sequence identity to other NATs of known structure.

  20. Structure and Functional Diversity of GCN5-Related N-Acetyltransferases (GNAT)

    PubMed Central

    Salah Ud-Din, Abu Iftiaf Md; Tikhomirova, Alexandra; Roujeinikova, Anna

    2016-01-01

    General control non-repressible 5 (GCN5)-related N-acetyltransferases (GNAT) catalyze the transfer of an acyl moiety from acyl coenzyme A (acyl-CoA) to a diverse group of substrates and are widely distributed in all domains of life. This review of the currently available data acquired on GNAT enzymes by a combination of structural, mutagenesis and kinetic methods summarizes the key similarities and differences between several distinctly different families within the GNAT superfamily, with an emphasis on the mechanistic insights obtained from the analysis of the complexes with substrates or inhibitors. It discusses the structural basis for the common acetyltransferase mechanism, outlines the factors important for the substrate recognition, and describes the mechanism of action of inhibitors of these enzymes. It is anticipated that understanding of the structural basis behind the reaction and substrate specificity of the enzymes from this superfamily can be exploited in the development of novel therapeutics to treat human diseases and combat emerging multidrug-resistant microbial infections. PMID:27367672

  1. Diurnal cycles in serotonin acetyltransferase activity and cyclic GMP content of cultured chick pineal glands.

    PubMed

    Wainwright, S D

    1980-06-12

    Levels of serotonin N-acetyltransferase (NAT: acetul CoA:arylamine N-acetyltransferase; EC 2.1.1.5.) activity in the chick pineal gland exhibit a marked diurnal variation in birds kept under a diurnal cycle of ilumination. Activity begins to rise rapidly at the start of the dark phase of the cycle and reaches maximum levels at mid-dark phase about 25-fold greater than the minimum basal level at mid-light phase. Thereafter, the level of activity declines to the basal level about the start of the light phase. This diurnal cycle in chick pineal NAT activity found in vivo has recently been reproduced in vitro with intact glands incubated in organ culture. The mechanism of the 'biological clock' which regulates these variations in level of chick pineal NAT activity is unknown. However, I now report that chick pineal glands cultured under a diurnal cycle of illumination exhibit a diurnal cycle in content of cyclic GMP which roughly parallels the cycles in NAT activity. In contrast, there was no correlation between variations in pineal content of cyclic AMP and in level of NAT activity. PMID:6250035

  2. Specific alkylation of a histidine residue in carnitine acetyltransferase by bromoacetyl-l-carnitine

    PubMed Central

    Chase, J. F. A.; Tubbs, P. K.

    1970-01-01

    Incubation of carnitine acetyltransferase with low concentrations of bromoacetyl-l-carnitine causes a rapid and irreversible loss of enzyme activity; one mol of inhibitor can inactivate one mol of enzyme. Bromoacetyl-d-carnitine, iodoacetate or iodoacetamide are ineffective. l-Carnitine protects the transferase from bromoacetyl-l-carnitine. Investigation shows that the enzyme first reversibly binds bromoacetyl-l-carnitine with an affinity similar to that shown for the normal substrate acetyl-l-carnitine; this binding is followed by an alkylation reaction, forming the carnitine ester of a monocarboxymethyl-protein, which is catalytically inactive. The carnitine is released at an appreciable rate by spontaneous hydrolysis, and the resulting carboxymethyl-enzyme is also inactive. Total acid hydrolysis of enzyme after treatment with 2-[14C]bromoacetyl-l-carnitine yields N-3-carboxy[14C]methylhistidine as the only labelled amino acid. These findings, taken in conjunction with previous work, suggest that the single active centre of carnitine acetyltransferase contains a histidine residue. PMID:5461620

  3. Crystal Structure Analysis of the Polysialic Acid Specific O-Acetyltransferase NeuO

    PubMed Central

    Schulz, Eike C.; Bergfeld, Anne K.; Ficner, Ralf; Mühlenhoff, Martina

    2011-01-01

    The major virulence factor of the neuroinvasive pathogen Escherichia coli K1 is the K1 capsule composed of α2,8-linked polysialic acid (polySia). K1 strains harboring the CUS-3 prophage modify their capsular polysaccharide by phase-variable O-acetlyation, a step that is associated with increased virulence. Here we present the crystal structure of the prophage-encoded polysialate O-acetyltransferase NeuO. The homotrimeric enzyme belongs to the left-handed β-helix (LβH) family of acyltransferases and is characterized by an unusual funnel-shaped outline. Comparison with other members of the LβH family allowed the identification of active site residues and proposal of a catalytic mechanism and highlighted structural characteristics of polySia specific O-acetyltransferases. As a unique feature of NeuO, the enzymatic activity linearly increases with the length of the N-terminal poly-ψ-domain which is composed of a variable number of tandem copies of an RLKTQDS heptad. Since the poly-ψ-domain was not resolved in the crystal structure it is assumed to be unfolded in the apo-enyzme. PMID:21390252

  4. Exchange of associated factors directs a switch in HBO1 acetyltransferase histone tail specificity.

    PubMed

    Lalonde, Marie-Eve; Avvakumov, Nikita; Glass, Karen C; Joncas, France-Hélène; Saksouk, Nehmé; Holliday, Michael; Paquet, Eric; Yan, Kezhi; Tong, Qiong; Klein, Brianna J; Tan, Song; Yang, Xiang-Jiao; Kutateladze, Tatiana G; Côté, Jacques

    2013-09-15

    Histone acetyltransferases (HATs) assemble into multisubunit complexes in order to target distinct lysine residues on nucleosomal histones. Here, we characterize native HAT complexes assembled by the BRPF family of scaffold proteins. Their plant homeodomain (PHD)-Zn knuckle-PHD domain is essential for binding chromatin and is restricted to unmethylated H3K4, a specificity that is reversed by the associated ING subunit. Native BRPF1 complexes can contain either MOZ/MORF or HBO1 as catalytic acetyltransferase subunit. Interestingly, while the previously reported HBO1 complexes containing JADE scaffold proteins target histone H4, the HBO1-BRPF1 complex acetylates only H3 in chromatin. We mapped a small region to the N terminus of scaffold proteins responsible for histone tail selection on chromatin. Thus, alternate choice of subunits associated with HBO1 can switch its specificity between H4 and H3 tails. These results uncover a crucial new role for associated proteins within HAT complexes, previously thought to be intrinsic to the catalytic subunit. PMID:24065767

  5. Structural and functional characterization of the α-tubulin acetyltransferase MEC-17

    PubMed Central

    Davenport, Andrew M.; Collins, Leslie N.; Chiu, Hui; Minor, Paul J.; Sternberg, Paul W.; Hoelz, André

    2014-01-01

    Tubulin protomers undergo an extensive array of post-translational modifications to tailor microtubules to specific tasks. One such modification, the acetylation of lysine-40 of α-tubulin, located in the lumen of microtubules, is associated with stable, long-living microtubule structures. MEC-17 was recently identified as the acetyltransferase that mediates this event. We have determined the crystal structure of the catalytic core of human MEC-17 in complex with its cofactor acetyl-CoA at 1.7 Å resolution. The structure reveals that the MEC-17 core adopts a canonical Gcn5-related N-acetyltransferase (GNAT) fold that is decorated with extensive surface loops. An enzymatic analysis of 33 MEC-17 surface mutants identifies hot-spot residues for catalysis and substrate recognition. A large, evolutionarily conserved hydrophobic surface patch is identified that is critical for enzymatic activity, suggesting that specificity is achieved by interactions with the α-tubulin substrate that extend outside of the modified surface loop. An analysis of MEC-17 mutants in C. elegans shows that enzymatic activity is dispensable for touch sensitivity. PMID:24846647

  6. Identification and characterization of novel small molecule inhibitors of the acetyltransferase activity of Escherichia coli N-acetylglucosamine-1-phosphate-uridyltransferase/glucosamine-1-phosphate-acetyltransferase (GlmU).

    PubMed

    Sharma, Rashmi; Rani, Chitra; Mehra, Rukmankesh; Nargotra, Amit; Chib, Reena; Rajput, Vikrant S; Kumar, Sunil; Singh, Samsher; Sharma, Parduman R; Khan, Inshad A

    2016-04-01

    This study aims at identifying novel chemical scaffolds as inhibitors specific to the acetyltransferase domain of a bifunctional enzyme, Escherichia coli GlmU, involved in the cell wall biosynthesis of Gram-negative organisms. A two-pronged approach was used to screen a 50,000 small-molecule library. Using the first approach, the library was in silico screened by docking the library against acetyltransferase domain of E. coli GlmU studies. In the second approach, complete library was screened against Escherichia coli ATCC 25922 to identify the whole cell active compounds. Active compounds from both the screens were screened in a colorimetric absorbance-based assay to identify inhibitors of acetyltransferase domain of E. coli GlmU which resulted in the identification of 1 inhibitor out of 56 hits identified by in silico screening and 4 inhibitors out of 35 whole cell active compounds on Gram-negative bacteria with the most potent inhibitor showing IC50 of 1.40 ± 0.69 μM. Mode of inhibition studies revealed these inhibitors to be competitive with AcCoA and uncompetitive with GlcN-1-P. These selected inhibitors were also tested for their antibacterial and cytotoxic activities. Compounds 5175178 and 5215319 exhibited antibacterial activity that co-related with GlmU inhibition. These compounds, therefore, represent novel chemical scaffolds targeting acetyltransferase activity of E. coli GlmU. PMID:26563552

  7. Looking from a CHAT-IT perspective to undergraduate Mexican physics: organizational trajectories or professors as agents of change?

    NASA Astrophysics Data System (ADS)

    Kahveci, Ajda

    2010-09-01

    Recent elaborations on cultural-historical activity theory (CHAT) (Engeström et al., eds., Perspectives on activity theory. New York: Cambridge University Press, 1999) and its relation to organizational theories have produced a theoretical amalgam of these earlier ideas, which allow for the exploration of learning in formal organizational contexts such as schools. In this paper I reflect on Candela's work situated in undergraduate Mexican physics by drawing attention to the CHAT-IT framework (Ogawa et al., Educational Researcher 37(2):83-95, 2008) as a viable lens. I suggest that it is important to understand the historical development of the Mexican university as an educational organization as well as the role of physics professors as agents of change whose practices contribute to not only breaking classroom walls but also to transforming the organization affecting future activity systems.

  8. Health-related message boards/chat rooms on the Web: discussion content and implications for pharmaceutical sponsorships.

    PubMed

    Macias, Wendy; Lewis, Liza Stavchansky; Smith, Tenikka L

    2005-01-01

    This content analysis study examined health-related message boards to better understand who is using this on-line health information and support device and what topics they are discussing. Besides needing to understand this support and coping mechanism for individuals, this has become an increasingly important topic for health communicators to understand because the Health and Human Services' (HHS) Inspector General recently gave permission to a pharmaceutical manufacturer for sponsorship of a disease management chat room. Very little research has been done on the content of these message boards/chat rooms. Key findings include that the most commonly discussed medical topics were medical treatments and drugs (often specific brands) and that these boards are clearly important sources of information and emotional support. Implication and future research are discussed. PMID:16036729

  9. Differential transcription of the human spermidine/spermine N1-acetyltransferase (SSAT) gene in human lung carcinoma cells.

    PubMed Central

    Xiao, L; Casero, R A

    1996-01-01

    The expression of spermidine/spermine N1-acetyltransferase (SSAT), the rate-limiting enzyme in the catabolism of polyamines, is highly regulated by a number of factors including the natural polyamines and their analogues. The phenotype-specific cytotoxicity that occurs in response to a class of polyamine analogues, the diethylpolyamines, is associated with a phenotype-specific superinduction of SSAT in human non-small-cell lung carcinomas, whereas in non-responding cell types, including the small-cell lung carcinomas, the superinduction of SSAT does not occur. In this study, we have investigated the molecular basis of this phenotype-specific SSAT induction in human lung carcinoma cells in response to N1,N12-diethylspermine (BESpm). To facilitate the study of transcriptional regulation, we have cloned and characterized 11 kb of the human SSAT locus, including 3500 bp of the 5' promoter region. Nuclear run-on transcription studies suggest that the initial induction of SSAT results from an increase in the rate of gene transcription. Results from Northern blot analysis and ribonuclease protection assays indicate a differential expression of SSAT mRNA between the analogue-responsive H157 and non-responsive H82 cells. There is no detectable SSAT mRNA in H82 cells, even after a 24-h analogue treatment, whereas SSAT mRNA in H157 cells was detectable by Northern blot analysis and increased more than 100-fold following drug exposure. Furthermore, nuclear run-on transcription assays do not detect any active transcription of SSAT gene in either treated or untreated H82 cells. These results indicate that at least one component of the phenotype-specific induction of SSAT appears to be due to differences in transcriptional regulation of the gene. In addition, mapping of DNase I-hypersensitive sites of the SSAT gene suggest that the cell type-specific promoter/enhancer utilization may control the expression of the SSAT gene in differentially sensitive cell types in vivo. PMID

  10. Difficulties in everyday life: Young persons with attention-deficit/hyperactivity disorder and autism spectrum disorders perspectives. A chat-log analysis

    PubMed Central

    Ahlström, Britt H; Wentz, Elisabet

    2014-01-01

    This study focuses on the everyday life of young persons with attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). There are follow-up studies describing ADHD, and ASD in adults, and residual impairments that affect life. Few qualitative studies have been conducted on the subject of their experiences of everyday life, and even fewer are from young persons’ perspectives. This study's aim was to describe how young persons with ADHD and ASD function and how they manage their everyday life based on analyses of Internet-based chat logs. Twelve young persons (7 males and 5 females aged 15–26) diagnosed with ADHD and ASD were included consecutively and offered 8 weeks of Internet-based Support and Coaching (IBSC). Data were collected from 12 chat logs (445 pages of text) produced interactively by the participants and the coaches. Qualitative content analysis was applied. The text was coded and sorted into subthemes and further interpreted into themes. The findings revealed two themes: “fighting against an everyday life lived in vulnerability” with the following subthemes: “difficult things,” “stress and rest,” and “when feelings and thoughts are a concern”; and the theme “struggling to find a life of one's own” with the following subthemes: “decide and carry out,” “making life choices,” and “taking care of oneself.” Dealing with the problematic situations that everyday encompasses requires personal strength and a desire to find adequate solutions, as well as to discover a role in society. This study, into the provision of support and coaching over the Internet, led to more in-depth knowledge about these young persons’ everyday lives and revealed their ability to use IBSC to express the complexity of everyday life for young persons with ADHD and ASD. The implications of the findings are that using online coaching makes available new opportunities for healthcare professionals to acknowledge these young

  11. Comparative genomic, phylogenetic, and functional investigation of the xenobiotic metabolizing arylamine N-acetyltransferase enzyme family among fungi

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Arylamine N-acetyltransferases (NATs) are xenobiotic metabolizing enzymes well-characterized in several bacteria and higher eukaryotes. The role of NATs in fungal biology has only recently been investigated (Glenn and Bacon, 2009; Glenn et al., 2010). The NAT1 gene of Gibberella moniliformis was the...

  12. Homologues of xenobiotic metabolizing N-acetyltransferases in plant-associated fungi: Novel functions for an old enzyme family

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant-pathogenic fungi and their hosts engage in chemical warfare, attacking each other with toxic products of secondary metabolism and defending themselves via an arsenal of xenobiotic metabolizing enzymes. One such enzyme is homologous to arylamine N-acetyltransferase (NAT) and has been identified...

  13. Chloramphenicol acetyltransferase should not provide methanogens with resistance to chloramphenicol. [Methanococcus voltae; Methanococcus vannielii; Methanococcus deltae; Methanobrevibacter smithii

    SciTech Connect

    Beckler, G.S.; Hook, L.A.; Reeve, J.N.

    1984-04-01

    Growth of the four methanogens investigated was inhibitied by chloramphenicol-3-acetate; therefore, introduction of chloramphenicol acetyltransferase-encoding genes should not confer chloramphenicol resistance on these methanogens. Reduction of the aryl nitro group of chloramphenicol produced a compound which did not inhibit the growth of these methanogens. 9 references.

  14. Dissociable roles for histone acetyltransferases p300 and PCAF in hippocampus and perirhinal cortex-mediated object memory.

    PubMed

    Mitchnick, K A; Creighton, S D; Cloke, J M; Wolter, M; Zaika, O; Christen, B; Van Tiggelen, M; Kalisch, B E; Winters, B D

    2016-07-01

    The importance of histone acetylation for certain types of memory is now well established. However, the specific contributions of the various histone acetyltransferases to distinct memory functions remain to be determined; therefore, we employed selective histone acetyltransferase protein inhibitors and short-interference RNAs to evaluate the roles of CREB-binding protein (CBP), E1A-binding protein (p300) and p300/CBP-associated factor (PCAF) in hippocampus and perirhinal cortex (PRh)-mediated object memory. Rats were tested for short- (STM) and long-term memory (LTM) in the object-in-place task, which relies on the hippocampus and PRh for spatial memory and object identity processing, respectively. Selective inhibition of these histone acetyltransferases by small-interfering RNA and pharmacological inhibitors targeting the HAT domain produced dissociable effects. In the hippocampus, CBP or p300 inhibition impaired long-term but not short-term object memory, while inhibition of PCAF impaired memory at both delays. In PRh, HAT inhibition did not impair STM, and only CBP and PCAF inhibition disrupted LTM; p300 inhibition had no effects. Messenger RNA analyses revealed findings consistent with the pattern of behavioral effects, as all three enzymes were upregulated in the hippocampus (dentate gyrus) following learning, whereas only CBP and PCAF were upregulated in PRh. These results demonstrate, for the first time, the necessity of histone acetyltransferase activity for PRh-mediated object memory and indicate that the specific mnemonic roles of distinctive histone acetyltransferases can be dissociated according to specific brain regions and memory timeframe. PMID:27251651

  15. Cri-Du-Chat Syndrome: Clinical Profile and Chromosomal Microarray Analysis in Six Patients.

    PubMed

    Espirito Santo, Layla Damasceno; Moreira, Lília Maria Azevedo; Riegel, Mariluce

    2016-01-01

    Cri-du-chat syndrome is a chromosomal disorder caused by a deletion of the short arm of chromosome 5. The disease severity, levels of intellectual and developmental delay, and patient prognosis have been related to the size and position of the deletion. Aiming to establish genotype-phenotype correlations, we applied array-CGH to evaluate six patients carrying cytogenetically detected deletions of the short arm of chromosome 5 who were followed at a genetics community service. The patients' cytogenetic and clinical profiles were reevaluated. A database review was performed to predict additional genes and regulatory elements responsible for the characteristic phenotypic and behavioral traits of this disorder. Array-CGH analysis allowed for delineation of the terminal deletions, which ranged in size from approximately 11.2 Mb to 28.6 Mb, with breakpoints from 5p15.2 to 5p13. An additional dup(8)(p23) (3.5 Mb), considered to be a benign copy number variation, was also observed in one patient. The correlation coefficient value (ρ = 0.13) calculated indicated the presence of a weak relationship between developmental delay and deletion size. Genetic background, family history, epigenetic factors, quantitative trait locus polymorphisms, and environmental factors may also affect patient phenotype and must be taken into account in genotype-phenotype correlations. PMID:27144168

  16. Cri-Du-Chat Syndrome: Clinical Profile and Chromosomal Microarray Analysis in Six Patients

    PubMed Central

    Espirito Santo, Layla Damasceno; Moreira, Lília Maria Azevedo; Riegel, Mariluce

    2016-01-01

    Cri-du-chat syndrome is a chromosomal disorder caused by a deletion of the short arm of chromosome 5. The disease severity, levels of intellectual and developmental delay, and patient prognosis have been related to the size and position of the deletion. Aiming to establish genotype-phenotype correlations, we applied array-CGH to evaluate six patients carrying cytogenetically detected deletions of the short arm of chromosome 5 who were followed at a genetics community service. The patients' cytogenetic and clinical profiles were reevaluated. A database review was performed to predict additional genes and regulatory elements responsible for the characteristic phenotypic and behavioral traits of this disorder. Array-CGH analysis allowed for delineation of the terminal deletions, which ranged in size from approximately 11.2 Mb to 28.6 Mb, with breakpoints from 5p15.2 to 5p13. An additional dup(8)(p23) (3.5 Mb), considered to be a benign copy number variation, was also observed in one patient. The correlation coefficient value (ρ = 0.13) calculated indicated the presence of a weak relationship between developmental delay and deletion size. Genetic background, family history, epigenetic factors, quantitative trait locus polymorphisms, and environmental factors may also affect patient phenotype and must be taken into account in genotype-phenotype correlations. PMID:27144168

  17. Can human-like Bots control collective mood: agent-based simulations of online chats

    NASA Astrophysics Data System (ADS)

    Tadić, Bosiljka; Šuvakov, Milovan

    2013-10-01

    Using an agent-based modeling approach, in this paper, we study self-organized dynamics of interacting agents in the presence of chat Bots. Different Bots with tunable ‘human-like’ attributes, which exchange emotional messages with agents, are considered, and the collective emotional behavior of agents is quantitatively analyzed. In particular, using detrended fractal analysis we determine persistent fluctuations and temporal correlations in time series of agent activity and statistics of avalanches carrying emotional messages of agents when Bots favoring positive/negative affects are active. We determine the impact of Bots and identify parameters that can modulate that impact. Our analysis suggests that, by these measures, the emotional Bots induce collective emotion among interacting agents by suitably altering the fractal characteristics of the underlying stochastic process. Positive emotion Bots are slightly more effective than negative emotion Bots. Moreover, Bots which periodically alternate between positive and negative emotion can enhance fluctuations in the system, leading to avalanches of agent messages that are reminiscent of self-organized critical states.

  18. Childhood apraxia of speech without intellectual deficit in a patient with cri du chat syndrome.

    PubMed

    Marignier, Stéphanie; Lesca, Gaetan; Marguin, Jessica; Bussy, Gérald; Sanlaville, Damien; des Portes, Vincent

    2012-06-01

    We report an 11-year-old girl for whom the diagnosis of cri du chat syndrome (CdCS) was made during a genetic investigation of childhood apraxia of speech. The patient presented with the classic chromosome 5 short arm deletion found in CdCS. The microdeletion, characterised using aCGH (array Comparative Genomic Hybridisation), was 12.85 Mb, overlapping the 5p15.2 and 5p15.3 critical regions. CdCS is typically associated with severe mental retardation while this patient had normal intellectual performance, confirmed by normal results from categorisation tasks. This mild phenotype was assessed using a comprehensive cognitive battery. Language evaluation showed normal receptive vocabulary scores, in contrast with obvious oro-facial dyspraxia. Disabled fine motor skills were confirmed as well as weak visuo-spatial reasoning abilities. In conclusion, fine cognitive assessment may be worthwhile for patients with CdCS since good intellectual functioning may be masked by severe speech and gestural dyspraxia, thus requiring specific teaching and rehabilitation strategies. PMID:22510527

  19. STS-87 Payload Specialist Leonid Kadenyuk chats with NASA Administrator Daniel Goldin shortly after

    NASA Technical Reports Server (NTRS)

    1997-01-01

    STS-87 Payload Specialist Leonid Kadenyuk of the National Space Agency of Ukraine (NSAU), at left, chats with NASA Administrator Daniel Goldin shortly after the landing of Columbia at Kennedy Space Center. Looking on is back-up Payload Specialist Yaroslav Pustovyi, also of NSAU. STS-87 concluded its mission with a main gear touchdown at 7:20:04 a.m. EST Dec. 5, at KSC's Shuttle Landing Facility Runway 33, drawing the 15-day, 16-hour and 34- minute-long mission of 6.5 million miles to a close. Also onboard the orbiter were Commander Kevin Kregel; Pilot Steven Lindsey; and Mission Specialists Winston Scott, Kalpana Chawla, Ph.D., and Takao Doi, Ph.D., of the National Space Development Agency of Japan. During the 88th Space Shuttle mission, the crew performed experiments on the United States Microgravity Payload-4 and pollinated plants as part of the Collaborative Ukrainian Experiment. This was the 12th landing for Columbia at KSC and the 41st KSC landing in the history of the Space Shuttle program.

  20. Facial Expression of Affect in Children with Cornelia de Lange Syndrome

    ERIC Educational Resources Information Center

    Collis, L.; Moss, J.; Jutley, J.; Cornish, K.; Oliver, C.

    2008-01-01

    Background: Individuals with Cornelia de Lange syndrome (CdLS) have been reported to show comparatively high levels of flat and negative affect but there have been no empirical evaluations. In this study, we use an objective measure of facial expression to compare affect in CdLS with that seen in Cri du Chat syndrome (CDC) and a group of…

  1. Isolation of bacteria producing chloramphenicol acetyltransferase from soil and their characterization.

    PubMed

    Datta, K; Mukherjee, S K; Majumdar, M K; Roy, S K

    1982-07-01

    After screening 107 soil samples collected from different spots around Calcutta, 579 chloramphenicol resistant colonies were isolated. Out of these only 58 colonies could inactivate chloramphenicol in detectable amounts. By noting the production of inactivating factor, 5 high yielding strains were further characterized to species level. Three of them were Escherichia coli strains, the two others were Alcaligenes faecalis and Klebsiella pneumoniae strains. All strains inactivated chloramphenicol by acetylation, with the production of chloramphenicol acetyltransferase. Production of this latter enzyme was not inducible. Minimum inhibitory concentrations for these 5 strains were studied against 14 antimicrobial agents. All strains were found to be resistant to most antimicrobial agents, but sensitive to polymyxin B. The strain A. faecalis was also sensitive to carbenicillin but other four strains were resistant to this antibiotic. PMID:6956790

  2. Unusual regioversatility of acetyltransferase Eis, a cause of drug resistance in XDR-TB

    SciTech Connect

    Chen, Wenjing; Biswas, Tapan; Porter, Vanessa R.; Tsodikov, Oleg V.; Garneau-Tsodikova, Sylvie

    2011-09-06

    The emergence of multidrug-resistant and extensively drug-resistant (XDR) tuberculosis (TB) is a serious global threat. Aminoglycoside antibiotics are used as a last resort to treat XDR-TB. Resistance to the aminoglycoside kanamycin is a hallmark of XDR-TB. Here, we reveal the function and structure of the mycobacterial protein Eis responsible for resistance to kanamycin in a significant fraction of kanamycin-resistant Mycobacterium tuberculosis clinical isolates. We demonstrate that Eis has an unprecedented ability to acetylate multiple amines of many aminoglycosides. Structural and mutagenesis studies of Eis indicate that its acetylation mechanism is enabled by a complex tripartite fold that includes two general control non-derepressible 5 (GCN5)-related N-acetyltransferase regions. An intricate negatively charged substrate-binding pocket of Eis is a potential target of new antitubercular drugs expected to overcome aminoglycoside resistance.

  3. Purification and characterization of aspartate N-acetyltransferase: A critical enzyme in brain metabolism.

    PubMed

    Wang, Qinzhe; Zhao, Mojun; Parungao, Gwenn G; Viola, Ronald E

    2016-03-01

    Canavan disease (CD) is a neurological disorder caused by an interruption in the metabolism of N-acetylaspartate (NAA). Numerous mutations have been found in the enzyme that hydrolyzes NAA, and the catalytic activity of aspartoacylase is significantly impaired in CD patients. Recent studies have also supported an important role in CD for the enzyme that catalyzes the synthesis of NAA in the brain. However, previous attempts to study this enzyme had not succeeded in obtaining a soluble, stable and active form of this membrane-associated protein. We have now utilized fusion constructs with solubilizing protein partners to obtain an active and soluble form of aspartate N-acetyltransferase. Characterization of the properties of this enzyme has set the stage for the development of selective inhibitors that can lower the elevated levels of NAA that are observed in CD patients and potentially serve as a new treatment therapy. PMID:26550943

  4. Inhibition of lyso-PAF: acetyl-CoA acetyltransferase by salicylates and other compounds.

    PubMed

    White, H L; Faison, L D

    1988-06-01

    Diflunisal and benoxaprofen (20-100 microM) produced dose-dependent inhibitions of lyso-platelet activating factor: acetyl-CoA acetyltransferase in a lysate of rat pleural neutrophils. Salicylate and aspirin were inhibitory at concentrations of 1 mM and above. Nordihydroguaiaretic acid was a relatively potent inhibitor (I50 = 6 microM). Other compounds, including anti-inflammatory steroids, cyclooxygenase and 5-lipoxygenase inhibitors, appeared ineffective at relevant concentrations. Inhibitions by diflunisal and salicylate occurred at concentrations similar to expected plasma levels in humans at therapeutic doses. An inhibition of platelet-activating factor synthesis may contribute to the antiinflammatory, analgesic, or antipyretic actions of these compounds. PMID:2903520

  5. Integration of Bioorthogonal Probes and Q-FRET for the Detection of Histone Acetyltransferase Activity.

    PubMed

    Han, Zhen; Luan, Yepeng; Zheng, Yujun George

    2015-12-01

    Histone acetyltransferases (HATs) are key players in the epigenetic regulation of gene function. The recent discovery of diverse HAT substrates implies a broad spectrum of cellular functions of HATs. Many pathological processes are also intimately associated with the dysregulation of HAT levels and activities. However, detecting the enzymatic activity of HATs has been challenging, and this has significantly impeded drug discovery. To advance the field, we developed a convenient one-pot, mix-and-read strategy that is capable of directly detecting the acylated histone product through a fluorescent readout. The strategy integrates three technological platforms-bioorthogonal HAT substrate labeling, alkyne-azide click chemistry, and quenching FRET-into one system for effective probing of HAT enzyme activity. PMID:26455821

  6. Potent Inhibitors of Acetyltransferase Eis Overcome Kanamycin Resistance in Mycobacterium tuberculosis.

    PubMed

    Willby, Melisa J; Green, Keith D; Gajadeera, Chathurada S; Hou, Caixia; Tsodikov, Oleg V; Posey, James E; Garneau-Tsodikova, Sylvie

    2016-06-17

    A major cause of tuberculosis (TB) resistance to the aminoglycoside kanamycin (KAN) is the Mycobacterium tuberculosis (Mtb) acetyltransferase Eis. Upregulation of this enzyme is responsible for inactivation of KAN through acetylation of its amino groups. A 123 000-compound high-throughput screen (HTS) yielded several small-molecule Eis inhibitors that share an isothiazole S,S-dioxide heterocyclic core. These were investigated for their structure-activity relationships. Crystal structures of Eis in complex with two potent inhibitors show that these molecules are bound in the conformationally adaptable aminoglycoside binding site of the enzyme, thereby obstructing binding of KAN for acetylation. Importantly, we demonstrate that several Eis inhibitors, when used in combination with KAN against resistant Mtb, efficiently overcome KAN resistance. This approach paves the way toward development of novel combination therapies against aminoglycoside-resistant TB. PMID:27010218

  7. Interferon-Induced Spermidine-Spermine Acetyltransferase and Polyamine Depletion Restrict Zika and Chikungunya Viruses.

    PubMed

    Mounce, Bryan C; Poirier, Enzo Z; Passoni, Gabriella; Simon-Loriere, Etienne; Cesaro, Teresa; Prot, Matthieu; Stapleford, Kenneth A; Moratorio, Gonzalo; Sakuntabhai, Anavaj; Levraud, Jean-Pierre; Vignuzzi, Marco

    2016-08-10

    Polyamines are small, positively charged molecules derived from ornithine and synthesized through an intricately regulated enzymatic pathway. Within cells, they are abundant and play several roles in diverse processes. We find that polyamines are required for the life cycle of the RNA viruses chikungunya virus (CHIKV) and Zika virus (ZIKV). Depletion of spermidine and spermine via type I interferon signaling-mediated induction of spermidine/spermine N1-acetyltransferase (SAT1), a key catabolic enzyme in the polyamine pathway, restricts CHIKV and ZIKV replication. Polyamine depletion restricts these viruses in vitro and in vivo, due to impairment of viral translation and RNA replication. The restriction is released by exogenous replenishment of polyamines, further supporting a role for these molecules in virus replication. Thus, SAT1 and, more broadly, polyamine depletion restrict viral replication and suggest promising avenues for antiviral therapies. PMID:27427208

  8. Structural Basis of Substrate-Binding Specificity of Human Arylamine N-acetyltransferases

    SciTech Connect

    Wu,H.; Dombrovsky, L.; Tempel, W.; Martin, F.; Loppnau, P.; Goodfellow, G.; Grant, D.; Plotnikov, A.

    2007-01-01

    The human arylamine N-acetyltransferases NAT1 and NAT2 play an important role in the biotransformation of a plethora of aromatic amine and hydrazine drugs. They are also able to participate in the bioactivation of several known carcinogens. Each of these enzymes is genetically variable in human populations, and polymorphisms in NAT genes have been associated with various cancers. Here we have solved the high resolution crystal structures of human NAT1 and NAT2, including NAT1 in complex with the irreversible inhibitor 2-bromoacetanilide, a NAT1 active site mutant, and NAT2 in complex with CoA, and have refined them to 1.7-, 1.8-, and 1.9- Angstroms resolution, respectively. The crystal structures reveal novel structural features unique to human NATs and provide insights into the structural basis of the substrate specificity and genetic polymorphism of these enzymes.

  9. Role of histone acetyltransferases and histone deacetylases in adipocyte differentiation and adipogenesis.

    PubMed

    Zhou, Yuanfei; Peng, Jian; Jiang, Siwen

    2014-04-01

    Adipogenesis is a complex process strictly regulated by a well-established cascade that has been thoroughly studied in the last two decades. This process is governed by complex regulatory networks that involve the activation/inhibition of multiple functional genes, and is controlled by histone-modifying enzymes. Among such modification enzymes, histone acetyltransferases (HATs) and histone deacetylases (HDACs) play important roles in the transcriptional regulation and post-translational modification of protein acetylation. HATs and HDACs have been shown to respond to signals that regulate cell differentiation, participate in the regulation of protein acetylation, mediate transcription and post-translation modifications, and directly acetylate/deacetylate various transcription factors and regulatory proteins. In this paper, we review the role of HATs and HDACs in white and brown adipocyte differentiation and adipogenesis, to expand our knowledge on fat formation and adipose tissue biology. PMID:24810880

  10. Structure of homoserine O-acetyltransferase from Staphylococcus aureus: the first Gram-positive ortholog structure

    PubMed Central

    Thangavelu, Bharani; Pavlovsky, Alexander G.; Viola, Ronald

    2014-01-01

    Homoserine O-acetyltransferase (HTA) catalyzes the formation of l-O-acetyl-homoserine from l-homoserine through the transfer of an acetyl group from acetyl-CoA. This is the first committed step required for the biosynthesis of methionine in many fungi, Gram-positive bacteria and some Gram-negative bacteria. The structure of HTA from Staphylococcus aureus (SaHTA) has been determined to a resolution of 2.45 Å. The structure belongs to the α/β-hydrolase superfamily, consisting of two distinct domains: a core α/β-domain containing the catalytic site and a lid domain assembled into a helical bundle. The active site consists of a classical catalytic triad located at the end of a deep tunnel. Structure analysis revealed some important differences for SaHTA compared with the few known structures of HTA. PMID:25286936

  11. Structure of homoserine O-acetyltransferase from Staphylococcus aureus: the first Gram-positive ortholog structure.

    PubMed

    Thangavelu, Bharani; Pavlovsky, Alexander G; Viola, Ronald

    2014-10-01

    Homoserine O-acetyltransferase (HTA) catalyzes the formation of L-O-acetyl-homoserine from L-homoserine through the transfer of an acetyl group from acetyl-CoA. This is the first committed step required for the biosynthesis of methionine in many fungi, Gram-positive bacteria and some Gram-negative bacteria. The structure of HTA from Staphylococcus aureus (SaHTA) has been determined to a resolution of 2.45 Å. The structure belongs to the α/β-hydrolase superfamily, consisting of two distinct domains: a core α/β-domain containing the catalytic site and a lid domain assembled into a helical bundle. The active site consists of a classical catalytic triad located at the end of a deep tunnel. Structure analysis revealed some important differences for SaHTA compared with the few known structures of HTA. PMID:25286936

  12. Preliminary X-ray crystallographic analysis of ornithine acetyltransferase (Rv1653) from Mycobacterium tuberculosis.

    PubMed

    Sankaranarayanan, R; Garen, C R; Cherney, M M; Yuan, M; Lee, C; James, M N G

    2009-02-01

    The gene product of open reading frame Rv1653 from Mycobacterium tuberculosis is annotated as encoding a probable ornithine acetyltransferase (OATase; EC 2.3.1.35), an enzyme that catalyzes two steps in the arginine-biosynthesis pathway. It transfers an acetyl group from N-acetylornithine to L-glutamate to produce N-acetylglutamate and L-ornithine. Rv1653 was crystallized using the sitting-drop vapour-diffusion method. The native crystals diffracted to a resolution of 1.7 A and belonged to space group P2(1)2(1)2(1), with unit-cell parameters a = 60.1, b = 99.7, c = 155.3 A. The preliminary X-ray study showed the presence of a dimer in the asymmetric unit of the crystals, which had a Matthews coefficient V(M) of 2.8 A(3) Da(-1). PMID:19194014

  13. Coenzyme A Binding to the Aminoglycoside Acetyltransferase (3)-IIIb Increases Conformational Sampling of Antibiotic Binding Site

    SciTech Connect

    Hu, Xiaohu; Norris, Adrianne; Baudry, Jerome Y; Serpersu, Engin H

    2011-01-01

    NMR spectroscopy experiments and molecular dynamics simulations were performed to describe the dynamic properties of the aminoglycoside acetyltransferase (3)-IIIb (AAC) in its apo and coenzyme A (CoASH) bound forms. The {sup 15}N-{sup 1}H HSQC spectra indicate a partial structural change and coupling of the CoASH binding site with another region in the protein upon the CoASH titration into the apo enzyme. Molecular dynamics simulations indicate a significant structural and dynamic variation of the long loop in the antibiotic binding domain in the form of a relatively slow (250 ns), concerted opening motion in the CoASH enzyme complex and that binding of the CoASH increases the structural flexibility of the loop, leading to an interchange between several similar equally populated conformations.

  14. First Things First: Vital Protein Marks by N-Terminal Acetyltransferases.

    PubMed

    Aksnes, Henriette; Drazic, Adrian; Marie, Michaël; Arnesen, Thomas

    2016-09-01

    N-terminal (Nt) acetylation is known to be a highly abundant co-translational protein modification, but the recent discovery of Golgi- and chloroplast-resident N-terminal acetyltransferases (NATs) revealed that it can also be added post-translationally. Nt-acetylation may act as a degradation signal in a novel branch of the N-end rule pathway, whose functions include the regulation of human blood pressure. Nt-acetylation also modulates protein interactions, targeting, and folding. In plants, Nt-acetylation plays a role in the control of resistance to drought and in regulation of immune responses. Mutations of specific human NATs that decrease their activity can cause either the lethal Ogden syndrome or severe intellectual disability and cardiovascular defects. In sum, recent advances highlight Nt-acetylation as a key factor in many biological pathways. PMID:27498224

  15. Effects of acute ethanol administration on nocturnal pineal serotonin N-acetyltransferase activity

    SciTech Connect

    Creighton, J.A.; Rudeen, P.K.

    1988-01-01

    The effect of acute ethanol administration on pineal serotonin N-acetyltransferase (NAT) activity, norepinephrine and indoleamine content was examined in male rats. When ethanol was administered in two equal doses (2 g/kg body weight) over a 4 hour period during the light phase, the nocturnal rise in NAT activity was delayed by seven hours. The nocturnal pineal norepinephrine content was not altered by ethanol except for a delay in the reduction of NE with the onset of the following light phase. Although ethanol treatment led to a significant reduction in nocturnal levels of pineal serotonin content, there was no significant effect upon pineal content of 5-hydroxyindoleacetic acid (5-HIAA). The data indicate that ethanol delays the onset of the rise of nocturnal pineal NAT activity.

  16. Absence of N-terminal acetyltransferase diversification during evolution of eukaryotic organisms

    PubMed Central

    Rathore, Om Singh; Faustino, Alexandra; Prudêncio, Pedro; Van Damme, Petra; Cox, Cymon J.; Martinho, Rui Gonçalo

    2016-01-01

    Protein N-terminal acetylation is an ancient and ubiquitous co-translational modification catalyzed by a highly conserved family of N-terminal acetyltransferases (NATs). Prokaryotes have at least 3 NATs, whereas humans have six distinct but highly conserved NATs, suggesting an increase in regulatory complexity of this modification during eukaryotic evolution. Despite this, and against our initial expectations, we determined that NAT diversification did not occur in the eukaryotes, as all six major human NATs were most likely present in the Last Eukaryotic Common Ancestor (LECA). Furthermore, we also observed that some NATs were actually secondarily lost during evolution of major eukaryotic lineages; therefore, the increased complexity of the higher eukaryotic proteome occurred without a concomitant diversification of NAT complexes. PMID:26861501

  17. Biochemical and structural analysis of aminoglycoside acetyltransferase Eis from Anabaena variabilis.

    PubMed

    Pricer, Rachel E; Houghton, Jacob L; Green, Keith D; Mayhoub, Abdelrahman S; Garneau-Tsodikova, Sylvie

    2012-10-30

    The Mycobacterium tuberculosis enhanced intracellular survival (Eis_Mtb) protein is a clinically important aminoglycoside (AG) multi-acetylating enzyme. Eis homologues are found in a variety of mycobacterial and non-mycobacterial species. Variation of the residues lining the AG-binding pocket and positions of the loops bearing these residues in the Eis homologues dictates the substrate specificity and, thus, Eis homologues are Nature-made tools for elucidating principles of AG recognition by Eis. Here, we demonstrate that the Eis from Anabaena variabilis (Eis_Ava), the first non-mycobacterial Eis homologue reported, is a multi-acetylating AG-acetyltransferase. Eis_Ava, Eis from Mycobacterium tuberculosis (Eis_Mtb), and Eis from Mycobacterium smegmatis (Eis_Msm) have different structures of their AG-binding pockets. We perform comparative analysis of these differences and investigate how they dictate the substrate and cosubstrate recognition and acetylation of AGs by Eis. PMID:23090428

  18. Streamflow, Water Quality, and Metal Loads from Chat Leachate and Mine Outflow into Tar Creek, Ottawa County, Oklahoma, 2005

    USGS Publications Warehouse

    Cope, Caleb C.; Becker, Mark F.; Andrews, William J.; DeHay, Kelli

    2008-01-01

    Picher mining district is an abandoned lead and zinc mining area located in Ottawa County, northeastern Oklahoma. During the first half of the 20th century, the area was a primary producer of lead and zinc in the United States. Large accumulations of mine tailings, locally referred to as chat, produce leachate containing cadmium, iron, lead, and zinc that enter drainages within the mining area. Metals also seep to local ground water and streams from unplugged shafts, vent holes, seeps, and abandoned mine dewatering wells. Streamflow measurements were made and water-quality samples were collected and analyzed from two locations in Picher mining district from August 16 to August 29 following a rain event beginning on August 14, 2005, to determine likely concentrations and loads of metals from tailings and mine outflows in the part of Picher mining district near Tar Creek. Locations selected for sampling included a tailings pile with an adjacent mill pond, referred to as the Western location, and a segment of Tar Creek from above the confluence with Lytle Creek to below Douthat bridge, referred to as Tar Creek Study Segment. Measured streamflow was less than 0.01 cubic foot per second at the Western location, with streamflow only being measurable at that site on August 16, 2005. Measured streamflows ranged from <0.01 to 2.62 cubic feet per second at Tar Creek Study Segment. One water-quality sample was collected from runoff at the Western location. Total metals concentrations in that sample were 95.3 micrograms per liter cadmium, 182 micrograms per liter iron, 170 micrograms per liter lead, 1,760 micrograms per liter zinc. Total mean metals concentrations in 29 water-quality samples collected from Tar Creek Study Segment from August 16-29, 2005, were 21.8 micrograms per liter cadmium, 7,924 micrograms per liter iron, 7.68 micrograms per liter lead, and 14,548 micrograms per liter zinc. No metals loading values were calculated for the Western location. Metals loading

  19. Members of the GCN5 histone acetyltransferase complex regulate PLETHORA-mediated root stem cell niche maintenance and transit amplifying cell proliferation in Arabidopsis.

    PubMed

    Kornet, Noortje; Scheres, Ben

    2009-04-01

    The PLETHORA (PLT) stem cell transcription factors form a developmentally instructive protein gradient in Arabidopsis thaliana roots. Histone acetylation is known to facilitate gene transcription and plays an important role in developmental processes. Here, we show that histone acetyltransferase GCN5 (for general control nonderepressible 5) attenuates the PLT gradient. Based on genetic evidence, we establish that GCN5 is essential for root stem cell niche maintenance and acts in the PLT pathway. The GCN5-associated factor ADA2b (for alteration/deficiency in activation 2b) is also positioned in the PLT pathway and regulates PLT expression, similar to GCN5. Both GCN5 and ADA2b mediate proliferation of the transit amplifying cells, but ADA2b does not affect stem cell niche maintenance. Overexpression of PLT2 rescues the stem cell niche defect of gcn5 mutants, indicating that GCN5 regulation of PLT expression is essential for maintenance of the root stem cell niche. We conclude that histone acetylation complexes play an important role in shaping a developmentally instructive gradient in the root. PMID:19376933

  20. Members of the GCN5 Histone Acetyltransferase Complex Regulate PLETHORA-Mediated Root Stem Cell Niche Maintenance and Transit Amplifying Cell Proliferation in Arabidopsis[W

    PubMed Central

    Kornet, Noortje; Scheres, Ben

    2009-01-01

    The PLETHORA (PLT) stem cell transcription factors form a developmentally instructive protein gradient in Arabidopsis thaliana roots. Histone acetylation is known to facilitate gene transcription and plays an important role in developmental processes. Here, we show that histone acetyltransferase GCN5 (for general control nonderepressible 5) attenuates the PLT gradient. Based on genetic evidence, we establish that GCN5 is essential for root stem cell niche maintenance and acts in the PLT pathway. The GCN5-associated factor ADA2b (for alteration/deficiency in activation 2b) is also positioned in the PLT pathway and regulates PLT expression, similar to GCN5. Both GCN5 and ADA2b mediate proliferation of the transit amplifying cells, but ADA2b does not affect stem cell niche maintenance. Overexpression of PLT2 rescues the stem cell niche defect of gcn5 mutants, indicating that GCN5 regulation of PLT expression is essential for maintenance of the root stem cell niche. We conclude that histone acetylation complexes play an important role in shaping a developmentally instructive gradient in the root. PMID:19376933