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Sample records for imprinted igf2 expression

  1. Monotreme IGF2 expression and ancestral origin of genomic imprinting.

    PubMed

    Killian, J K; Nolan, C M; Stewart, N; Munday, B L; Andersen, N A; Nicol, S; Jirtle, R L

    2001-08-15

    IGF2 (insulin-like growth factor 2) and M6P/IGF2R (mannose 6-phosphate/insulin-like growth factor 2 receptor) are imprinted in marsupials and eutherians but not in birds. These results along with the absence of M6P/IGF2R imprinting in the egg-laying monotremes indicate that the parental imprinting of fetal growth-regulatory genes may be unique to viviparous mammals. In this investigation, we have cloned IGF2 from two monotreme mammals, the platypus and echidna, to further investigate the origin of imprinting. We report herein that like M6P/IGF2R, IGF2 is not imprinted in monotremes. Thus, although IGF2 encodes for a highly conserved growth factor in chordates, it is only imprinted in therian mammals. These findings support a concurrent origin of IGF2 and M6P/IGF2R imprinting in the late Jurassic/early Cretaceous period. The absence of imprinting in monotremes, despite apparent interparental conflicts over maternal-offspring exchange, argues that a fortuitous congruency of genetic and epigenetic events may have limited the phylogenetic breadth of genomic imprinting to therian mammals. J. Exp. Zool. (Mol. Dev. Evol.) 291:205-212, 2001.

  2. Tissue specificity and variability of imprinted IGF2 expression in humans

    SciTech Connect

    Giannoukakis, N.; Rouleau, G.; Polychronakos, C.

    1994-09-01

    Parental genomic imprinting refers to the phenomenon where expression of a gene copy depends on the sex of the parent from which it is derived. The human insulin-like growth factor II gene, IGF2, is parentally imprinted with the paternal gene copy exclusively expressed in fetal and term placenta as well as in fetal kidney. In mice, imprinted IGF2 expression is tissue-specific. In a preliminary approach to investigate tissue-specific IGF2 imprinting in humans, we evaluated allele-specific expression in four samples of umbilical cord blood leukocytes of fetuses found to imprint IGF2 in placenta. IGF2 mRNA transcripts from the gene copy transmitted from each parent were distinguished using a transcribed ApaI polymorphism by performing reverse transcription-PCR on total RNA from cord blood leukocytes. Postnatal peripheral blood was examined using the same method. Of 77 informative individuals, 68 expressed both IGF2 copies, but 9 individuals showed unambiguous monoallelic expression. Two individuals from each category were screened again and the results were identical. These data indicate that imprinted IGF2 expression is tissue-specific and show variability of IGF2 imprinting among individuals. This variability may be genetic. We are in the process of screening large pedigrees to test this hypothesis.

  3. Promoter-specific expression and imprint status of marsupial IGF2.

    PubMed

    Stringer, Jessica M; Suzuki, Shunsuke; Pask, Andrew J; Shaw, Geoff; Renfree, Marilyn B

    2012-01-01

    In mice and humans, IGF2 has multiple promoters to maintain its complex tissue- and developmental stage-specific imprinting and expression. IGF2 is also imprinted in marsupials, but little is known about its promoter region. In this study, three IGF2 transcripts were isolated from placental and liver samples of the tammar wallaby, Macropus eugenii. Each transcript contained a unique 5' untranslated region, orthologous to the non-coding exons derived from promoters P1-P3 in the human and mouse IGF2 locus. The expression of tammar IGF2 was predominantly from the P2 promoter, similar to humans. Expression of IGF2 was higher in pouch young than in the adult and imprinting was highly tissue and developmental-stage specific. Interestingly, while IGF2 was expressed throughout the placenta, imprinting seemed to be restricted to the vascular, trilaminar region. In addition, IGF2 was monoallelically expressed in the adult mammary gland while in the liver it switched from monoalleleic expression in the pouch young to biallelic in the adult. These data suggest a complex mode of IGF2 regulation in marsupials as seen in eutherian mammals. The conservation of the IGF2 promoters suggests they originated before the divergence of marsupials and eutherians, and have been selectively maintained for at least 160 million years.

  4. Analysis of imprinted IGF2/H19 gene methylation and expression in normal fertilized and parthenogenetic embryonic stem cells of pigs.

    PubMed

    Uh, Kyung-Jun; Park, Chi-Hun; Choi, Kwang-Hwan; Park, Jin-Kyu; Jeong, Yeon-Woo; Roh, Sangho; Hyun, Sang-Hwan; Shin, Taeyoung; Lee, Chang-Kyu; Hwang, Woo Suk

    2014-06-10

    To determine whether the genomic imprinting can be maintained during the process of embryonic stem (ES) cell derivation from pig blastocysts, mRNA and DNA methylation at the IGF2/H19 imprinting control region in putative ES cells derived from in vitro fertilized (IVF) and parthenogenetic (PG) embryos were investigated. In the present study, one IVF- and three PG ES-like cell lines were established and analyzed for cellular characteristics such as pluripotent marker expression and differentiation capacity. The results showed that these putative ES cells derived from pig blastocysts fulfilled the general "stemness" criteria. The expression of the H19 gene was significantly greater in PG blastocysts than IVF blastocysts, but there were greater amounts of IGF2 in IVF than PG blastocysts. Of these putative ES cell lines, one PG line had less H19 gene expression than a IVF ES cell line while the other two PG lines had much greater expression of the H19 gene than the IVF line. In contrast, the IGF2 gene was upregulated in the same PG cell line relative to the other two PG cell lines and transcript abundance was similar to IVF ES-like cells. Despite the variable amounts of mRNA among the PG cell lines, the IGF2/H19 gene had a differentially methylated region (DMR) 3 was typically un-methylated in all PG cells, and hemi-methylated in the IVF cells. These findings indicated that the mRNA of H19 and IGF2 genes is susceptible to in vitro environments during the process of ES cell derivation from blastocysts but DNA methylation status at this region was well maintained. These altered gene expressions may not be associated with the methylation of the imprinting control region at this locus. Therefore, with their uni-parental genotype, the pluripotent differentiation potentials of PG ES cells could be a valuable tool for understanding genomic imprinting in embryonic development.

  5. Relaxation of IGF2 imprinting in Wilms tumours associated with specific changes in IGF2 methylation.

    PubMed

    Sullivan, M J; Taniguchi, T; Jhee, A; Kerr, N; Reeve, A E

    1999-12-09

    Relaxation of IGF2 imprinting occurs in Wilms tumours and many other cancers, but the mechanism of loss of imprinting (LOI) remains unknown. To investigate the role of altered DNA methylation in LOI, we examined the pattern of methylation of the human insulin-IGF2 region in Wilms tumours and the normal kidney. The analysis included regions homologous to three 'differentially methylated regions' of the mouse Igf2 gene (dmrs 0, 1 and 2). In tumours displaying normal IGF2 imprinting, and in the normal kidney, maternal allele-specific DNA methylation was identified spanning exons 2 and 3. This region is homologous to dmr 0, a site of maternal-specific differential methylation in the mouse. In Wilms tumours with relaxed imprinting or 11p15.5 LOH this region was unmethylated. No other differential methylation was identified. In particular, two sites of paternal methylation in the mouse (dmrs 1 and 2), and all three imprinted IGF2 promoters were not methylated in the kidney or in Wilms tumours. We postulate that LOI in Wilms tumours is associated with loss of maternal allele-specific methylation from a region located upstream of the imprinted IGF2 promoters. This region may contain cis acting sequences that coordinately influence imprinting.

  6. Differential genomic imprinting regulates paracrine and autocrine roles of IGF2 in mouse adult neurogenesis

    PubMed Central

    Ferrón, S. R.; Radford, E. J.; Domingo-Muelas, A.; Kleine, I.; Ramme, A.; Gray, D.; Sandovici, I.; Constancia, M.; Ward, A.; Menheniott, T. R.; Ferguson-Smith, A. C.

    2015-01-01

    Genomic imprinting is implicated in the control of gene dosage in neurogenic niches. Here we address the importance of Igf2 imprinting for murine adult neurogenesis in the subventricular zone (SVZ) and in the subgranular zone (SGZ) of the hippocampus in vivo. In the SVZ, paracrine IGF2 is a cerebrospinal fluid and endothelial-derived neurogenic factor requiring biallelic expression, with mutants having reduced activation of the stem cell pool and impaired olfactory bulb neurogenesis. In contrast, Igf2 is imprinted in the hippocampus acting as an autocrine factor expressed in neural stem cells (NSCs) solely from the paternal allele. Conditional mutagenesis of Igf2 in blood vessels confirms that endothelial-derived IGF2 contributes to NSC maintenance in SVZ but not in the SGZ, and that this is regulated by the biallelic expression of IGF2 in the vascular compartment. Our findings indicate that a regulatory decision to imprint or not is a functionally important mechanism of transcriptional dosage control in adult neurogenesis. PMID:26369386

  7. Relaxation of IGF2/H19 imprinting in Wilms tumour is associated with a switch in DNA methylation

    SciTech Connect

    Reeve, A.E.; Taniguchi, T.; Sullivan, M.J.; Ogawa, O.

    1994-09-01

    We and others have recently shown that the normal imprinting of the insulin-like growth factor 2 (IGF2) gene is disrupted in Wilms tumor. The process of relaxation of IGF2 imprinting leads to the activation of transcription of the normally silent maternally inherited IGF2 allele such that both alleles of the IGF2 gene are transcribed. Relaxation of IGF2 imprinting has also been detected as a constitutional event in patients with the Beckwith-Wiedemann syndrom and a patient with gigantism and Wilms tumor. We have now shown that in Wilms tumors in which imprinting is relaxed, IGF2 is transcribed from the maternal allele and there is a concomitant transcriptional inactivation of the H19 maternal allele. Furthermore, the patterns of methylation of the IGF2 and H19 gene are reversed on the maternal chromosome. Relaxation of imprinting in Wilms tumors appear, therefore, to be associated with a switch in gene expression and methylation at the IGF2/H19 locus. The data supports the notion of a disrupted IGF2/H19 imprinting switch in Wilms tumor.

  8. Activation of an imprinted Igf 2 gene in mouse somatic cell cultures.

    PubMed Central

    Eversole-Cire, P; Ferguson-Smith, A C; Sasaki, H; Brown, K D; Cattanach, B M; Gonzales, F A; Surani, M A; Jones, P A

    1993-01-01

    The mouse insulin-like growth factor II gene (Igf 2), located on distal chromosome 7, is parentally imprinted such that the paternal allele is expressed while the maternal allele is transcriptionally silent. We derived a cell line from a mouse embryo maternally disomic and paternally deficient for distal chromosome 7 (MatDi7) to determine the stability of gene repression in culture. MatDi7 cells maintained Igf2 in a repressed state even after immortalization, except for one randomly picked clone which spontaneously expressed the gene. Igf 2 was expressed in a cell culture derived from a normal littermate; this expression was growth regulated, with Igf 2 mRNA levels increasing in the stationary phase of growth. Analysis of the methylation status of 28 sites distributed over 10 kb of the gene did not show consistent differences associated with expression level in the normal and MatDi7 cell lines, and the CpG island in the Igf 2 promoter remained unmethylated in all of the cell lines. Only with an oncogenically transformed cell line did the promoter become extensively methylated. We attempted to derepress the imprinted gene in MatDi7 cells by treatments known to alter gene expression. Expression of the Igf 2 allele in MatDi7 cells was increased in a dose-dependent manner by treatment with 5-aza-2'-deoxycytidine or bromodeoxyuridine, agents known to change DNA methylation patterns or chromatin conformation. Treatment of the cells with 1-beta-D-arabinofuranosylcytosine, 2'-deoxycytidine, calcium ionophore, heat shock, cold shock, or sodium butyrate did not result in increases in the levels of Igf 2 expression. It seems likely that the mechanism of the Igf 2 imprint involves subtle changes in the methylation or chromatin conformation of the gene which are affected by 5-aza-2'-deoxycytidine and bromodeoxyuridine. Images PMID:8336727

  9. Allelic switching of the imprinted IGF2R gene in cloned bovine fetuses and calves.

    PubMed

    Suteevun-Phermthai, T; Curchoe, C L; Evans, A C; Boland, E; Rizos, D; Fair, T; Duffy, P; Sung, L Y; Du, F; Chaubal, S; Xu, J; Wechayant, T; Yang, X; Lonergan, P; Parnpai, R; Tian, X C

    2009-11-01

    Cloned animals often suffer from loss of development to term and abnormalities, typically classified under the umbrella term of Large Offspring Syndrome (LOS). Cattle are an interesting species to study because of the relatively greater success rate of nuclear transfer in this species compared with all species cloned to date. The imprinted insulin-like growth factor receptor (IGF2R; mannose-6-phosphate) gene was chosen to investigate aspects of fetal growth and development in cloned cattle in the present study. IGF2R gene expression patterns in identical genetic clones of several age groups were assessed in day 25, day 45, and day 75 fetuses as well as spontaneously aborted fetuses, calves that died shortly after birth and healthy cloned calves using single stranded conformational polymorphism gel electrophoresis. A variable pattern of IGF2R allelic expression in major organs such as the brain, cotyledon, heart, liver, lung, spleen, kidney and intercotyledon was observed using a G/A transition in the 3'UTR of IGF2R. IGF2R gene expression was also assessed by real time RT-PCR and found to be highly variable among the clone groups. Proper IGF2R gene expression is necessary for survival to term, but is most likely not a cause of early fetal lethality or an indicator of postnatal fitness. Contrary to previous reports of the transmission of imprinting patterns from somatic donor cells to cloned animals within organs in the same cloned animal the paternal allele of IGF2R can be imprinted in one tissue while the maternal allele is imprinted in another tissue. This observation has never been reported in any species in which imprinting has been studied.

  10. Loss of imprinting of the insulin-like growth factor II (IGF2) gene in esophageal normal and adenocarcinoma tissues.

    PubMed

    Zhao, Ronghua; DeCoteau, John F; Geyer, C Ronald; Gao, Mei; Cui, Hengmi; Casson, Alan G

    2009-12-01

    To evaluate loss of imprinting (LOI) and expression of the IGF2 gene in matched esophageal normal and adenocarcinoma tissues, we studied a prospective cohort of 77 patients who underwent esophageal resection between 1998 and 2003. IGF2 imprinting status was determined by reverse transcription-polymerase chain reaction (PCR) following ApaI digestion, and quantitative PCR was used to evaluate IGF2 expression, which was correlated with clinicopathologic findings, disease-free and overall survival. In total, 32% (14/44) of informative tissues showed loss of IGF2 imprinting, with a strong correlation between the tumor and normal esophageal epithelia (Kappa = 0.89, P < 0.01). Normal epithelia with LOI had increased expression of IGF2 [median: 2.91, 95% confidence interval (CI): 0.93-5.06] compared with imprinted normal epithelia (median: 1.13, 95% CI: 0.85-1.39) (P = 0.03). In contrast, tumors with LOI had significantly reduced IGF2 expression (median: 1.87, 95% CI: 0.53-5.21) compared with normally imprinted tumors (median: 6.79, 95% CI: 3.39-15.89) (P = 0.016). Patients below the age of 65 years with normally imprinted tumors had significantly reduced 5 year disease-free survival (DFS) (24%) compared with patients whose tumors had LOI for IGF2 (55%) (P = 0.03). Cox regression analysis showed that IGF2 overexpression was associated with significantly reduced disease-free survival (P = 0.04). We conclude that in a subgroup of younger patients, loss of IGF2 imprinting was associated with improved outcome following esophageal resection. Expression of IGF2 in esophageal adenocarcinoma and normal esophageal epithelia depended on imprinting status and tissue type, suggesting novel molecular regulatory mechanisms in esophageal tumorigenesis.

  11. A transcriptional insulator at the imprinted H19/Igf2 locus

    PubMed Central

    Kaffer, Christopher R.; Srivastava, Madhulika; Park, Kye-Yoon; Ives, Elizabeth; Hsieh, Sandra; Batlle, Juan; Grinberg, Alexander; Huang, Sing-Ping; Pfeifer, Karl

    2000-01-01

    Igf2 and H19 exhibit parent-of-origin-specific monoallelic expression. H19 is expressed from the maternal chromosome and Igf2 from the paternal. The two genes share enhancer elements and monoallelic expression of both genes is dependent on cis-acting sequences upstream of the H19 promoter. In this work we examine the mechanisms by which this region silences the maternal Igf2 allele and we demonstrate that deletion of this region can result in high levels of activation of both H19 and Igf2 from a single chromosome. Moreover, by inserting this cis element between a promoter and its enhancer at a heterologous position, we demonstrate that the sequences carry both insulator activity and the ability to be stably imprinted. We also characterize the insulator in vitro and show that it is neither enhancer nor promoter specific. PMID:10921905

  12. Developmental profile of H19 differentially methylated domain (DMD) deletion alleles reveals multiple roles of the DMD in regulating allelic expression and DNA methylation at the imprinted H19/Igf2 locus.

    PubMed

    Thorvaldsen, Joanne L; Fedoriw, Andrew M; Nguyen, Son; Bartolomei, Marisa S

    2006-02-01

    The differentially methylated domain (DMD) of the mouse H19 gene is a methylation-sensitive insulator that blocks access of the Igf2 gene to shared enhancers on the maternal allele and inactivates H19 expression on the methylated paternal allele. By analyzing H19 DMD deletion alleles H19DeltaDMD and H19Delta3.8kb-5'H19 in pre- and postimplantation embryos, we show that the DMD exhibits positive transcriptional activity and is required for H19 expression in blastocysts and full activation of H19 during subsequent development. We also show that the DMD is required to establish Igf2 imprinting by blocking access to shared enhancers when Igf2 monoallelic expression is initiated in postimplantation embryos and that the single remaining CTCF site of the H19DeltaDMD allele is unable to provide this function. Furthermore, our data demonstrate that sequence outside of the DMD can attract some paternal-allele-specific CpG methylation 5' of H19 in preimplantation embryos, although this methylation is not maintained during postimplantation in the absence of the DMD. Finally, we report a conditional allele floxing the 1.6-kb sequence deleted from the H19DeltaDMD allele and demonstrate that the DMD is required to maintain repression of the maternal Igf2 allele and the full activity of the paternal Igf2 allele in neonatal liver.

  13. Ancestral TCDD exposure promotes epigenetic transgenerational inheritance of imprinted gene Igf2: Methylation status and DNMTs.

    PubMed

    Ma, Jing; Chen, Xi; Liu, Yanan; Xie, Qunhui; Sun, Yawen; Chen, Jingshan; Leng, Ling; Yan, Huan; Zhao, Bin; Tang, Naijun

    2015-12-01

    Ancestral TCDD exposure could induce epigenetic transgenerational phenotypes, which may be mediated in part by imprinted gene inheritance. The aim of our study was to evaluate the transgenerational effects of ancestral TCDD exposure on the imprinted gene insulin-like growth factor-2 (Igf2) in rat somatic tissue. TCDD was administered daily by oral gavage to groups of F0 pregnant SD rats at dose levels of 0 (control), 200 or 800 ng/kg bw during gestation day 8-14. Animal transgenerational model of ancestral exposure to TCDD was carefully built, avoiding sibling inbreeding. Hepatic Igf2 expression of the TCDD male progeny was decreased concomitantly with hepatic damage and increased activities of serum hepatic enzymes both in the F1 and F3 generation. Imprinted Control Region (ICR) of Igf2 manifested a hypermethylated pattern, whereas methylation status in the Differentially Methylated Region 2 (DMR2) showed a hypomethylated manner in the F1 generation. These epigenetic alterations in these two regions maintained similar trends in the F3 generation. Meanwhile, the expressions of DNA methyltransferases (DNMT1, DNMT3A and DNMT3B) changed in a non-monotonic manner both in the F1 and F3 generation. This study provides evidence that ancestral TCDD exposure may promote epigenetic transgenerational alterations of imprinted gene Igf2 in adult somatic tissue.

  14. Expression of KCNQ1OT1, CDKN1C, H19, and PLAGL1 and the methylation patterns at the KvDMR1 and H19/IGF2 imprinting control regions is conserved between human and bovine

    PubMed Central

    2012-01-01

    Background Beckwith-Wiedemann syndrome (BWS) is a loss-of-imprinting pediatric overgrowth syndrome. The primary features of BWS include macrosomia, macroglossia, and abdominal wall defects. Secondary features that are frequently observed in BWS patients are hypoglycemia, nevus flammeus, polyhydramnios, visceromegaly, hemihyperplasia, cardiac malformations, and difficulty breathing. BWS is speculated to occur primarily as the result of the misregulation of imprinted genes associated with two clusters on chromosome 11p15.5, namely the KvDMR1 and H19/IGF2. A similar overgrowth phenotype is observed in bovine and ovine as a result of embryo culture. In ruminants this syndrome is known as large offspring syndrome (LOS). The phenotypes associated with LOS are increased birth weight, visceromegaly, skeletal defects, hypoglycemia, polyhydramnios, and breathing difficulties. Even though phenotypic similarities exist between the two syndromes, whether the two syndromes are epigenetically similar is unknown. In this study we use control Bos taurus indicus X Bos taurus taurus F1 hybrid bovine concepti to characterize baseline imprinted gene expression and DNA methylation status of imprinted domains known to be misregulated in BWS. This work is intended to be the first step in a series of experiments aimed at determining if LOS will serve as an appropriate animal model to study BWS. Results The use of F1 B. t. indicus x B. t. taurus tissues provided us with a tool to unequivocally determine imprinted status of the regions of interest in our study. We found that imprinting is conserved between the bovine and human in imprinted genes known to be associated with BWS. KCNQ1OT1 and PLAGL1 were paternally-expressed while CDKN1C and H19 were maternally-expressed in B. t. indicus x B. t. taurus F1 concepti. We also show that in bovids, differential methylation exists at the KvDMR1 and H19/IGF2 ICRs. Conclusions Based on these findings we conclude that the imprinted gene expression of

  15. Microdeletions in the human H19 DMR result in loss of IGF2 imprinting and Beckwith-Wiedemann syndrome.

    PubMed

    Sparago, Angela; Cerrato, Flavia; Vernucci, Maria; Ferrero, Giovanni Battista; Silengo, Margherita Cirillo; Riccio, Andrea

    2004-09-01

    The overgrowth- and tumor-associated Beckwith-Wiedemann syndrome results from dysregulation of imprinted genes on chromosome 11p15.5. Here we show that inherited microdeletions in the H19 differentially methylated region (DMR) that abolish two CTCF target sites cause this disease. Maternal transmission of the deletions results in hypermethylation of the H19 DMR, biallelic IGF2 expression, H19 silencing and Beckwith-Wiedemann syndrome, indicative of loss of function of the IGF2-H19 imprinting control element.

  16. Long-range DNase I hypersensitivity mapping reveals the imprinted Igf2r and Air promoters share cis-regulatory elements

    PubMed Central

    Pauler, Florian M.; Stricker, Stefan H.; Warczok, Katarzyna E.; Barlow, Denise P.

    2005-01-01

    Epigenetic mechanisms restrict the expression of imprinted genes to one parental allele in diploid cells. At the Igf2r/Air imprinted cluster on mouse chromosome 17, paternal-specific expression of the Air noncoding RNA has been shown to silence three genes in cis: Igf2r, Slc22a2, and Slc22a3. By an unbiased mapping of DNase I hypersensitive sites (DHS) in a 192-kb region flanking Igf2r and Air, we identified 21 DHS, of which nine mapped to evolutionarily conserved sequences. Based on the hypothesis that silencing effects of Air would be directed towards cis regulatory elements used to activate genes, DHS are potential key players in the control of imprinted expression. However, in this 192-kb region only the two DHS mapping to the Igf2r and Air promoters show parental specificity. The remaining 19 DHS were present on both parental alleles and, thus, have the potential to activate Igf2r on the maternal allele and Air on the paternal allele. The possibility that the Igf2r and Air promoters share the same cis-acting regulatory elements, albeit on opposite parental chromosomes, was supported by the similar expression profiles of Igf2r and Air in vivo. These results refine our understanding of the onset of imprinted silencing at this cluster and indicate the Air noncoding RNA may specifically target silencing to the Igf2r promoter. PMID:16204191

  17. A Cis-acting locus determines the polymorphic parental imprinting of the human IGF2R gene

    SciTech Connect

    Xu, Y.; Polychronakos, C.

    1994-09-01

    The murine gene encoding the insulin-like growth factor receptor (IGF2R) is parentally imprinted in the mouse with exclusive maternal expression, but most humans express both gene copies. We have reported preferential expression of the maternal copy in approximately 17% of normal human pre-term placenta samples and in 50% of the kidneys of Wilms` tumor patients. Thus, IGF2R imprinting appears to be a polymorphic trait that may predispose to cancer. We explored the possibility that imprinting is associated with sequence variations of the imprinted domain itself (cis-acting locus). We studied 9 subjects with imprinted IGF2R expression that were informative for parental origin. These subjects were heterozygous for a transcribed CA repeat at the 3{prime}UTR of the gene, used for the study of the parental origin of mRNA transcripts. The two most common alleles, A162 and A164 (names refer to size in bp), were analyzed. In all cases the preferentially transcribed allele was maternal (p=0.002). In all 8 cases in which A164 was present, it was of paternal origin and was repressed (p=0.008), while A162 was maternal and preferentially expressed in 8/9 cases. Parental origin of A162 and A164 was random in individuals with biallelic expression. PCR amplification of genomic DNA after digestion with the methylation-sensitive enzyme HpaII revealed biallelic methylation at the 3{prime}UTR in both imprinting and non-imprinting individuals, making it unlikely that the imprint-controlling element (ICE) is located there. Polymorphic IGF2R imprinting depends on a cis-acting locus, at linkage disequilibrium with, but probably distinct from, our 3{prime}UTR marker. Biallelic expression in many subjects with a paternal A164 suggests that the frequency of the imprintable ICE is much lower than that of A164. Alternatively, the cis-locus is necessary but not sufficient and input in trans is additionally required for paternal-germline specific IGF2R repression.

  18. The Impact of First Trimester Phthalate and Phenol Exposure on IGF2/H19 Genomic Imprinting and Birth Outcomes

    PubMed Central

    LaRocca, Jessica; Binder, Alexandra; McElrath, Thomas F.; Michels, Karin B.

    2014-01-01

    Genomic imprinting leads to parent-of-origin specific gene expression and is determined by epigenetic modification of genes. The paternally expressed gene insulin-like growth-factor 2 (IGF2) is located about ∼100 kb from the maternally expressed non-coding gene H19 on human chromosome 11, and both genes play major roles in embryonic and placental growth. Given adverse gestational environments can influence DNA methylation patterns in extra-embryonic tissues, we hypothesized that prenatal exposure to endocrine disrupting chemicals (EDCs) alters H19 and IGF2 methylation in placenta. Our study was restricted to a total of 196 women co-enrolled in the Predictors of Preeclampsia Study and the Harvard Epigenetic Birth Cohort. First trimester urine concentrations of 8 phenols and 11 phthalate metabolites were measured and used to characterize EDC exposure profiles. We assessed methylation of differentially methylated regions (DMRs) by pyrosequencing of H19, IGF2DMR0, and IGF2DMR2 and correlated values with phenol and phthalate metabolites. We also assessed overall expression and allele-specific expression of H19 and IGF2. We found several significant associations between DNA methylation and additive biomarker measurements. A significant decrease in H19 methylation was associated with high level of the sum (Σ) of phthalate metabolites and metabolites of low molecular weight (LMW) phthalates. Σphthalate and LMW phthalate concentrations were inversely associated with IGF2DMR0 methylation values. Variation in methylation was not associated with changes in allele-specific expression. However increased deviation of allele-specific expression of H19 was associated with Σ di(2-ethylhexyl) phthalate metabolites and high molecular weight phthalates. Neither methylation nor expression of these imprinted regions had a significant impact on birth length or birth weight. Overall, our study provides new insight into an epigenetic mechanism that occurs following EDC exposure. PMID

  19. Humanized H19/Igf2 locus reveals diverged imprinting mechanism between mouse and human and reflects Silver–Russell syndrome phenotypes

    PubMed Central

    Hur, Stella K.; Freschi, Andrea; Ideraabdullah, Folami; Thorvaldsen, Joanne L.; Luense, Lacey J.; Weller, Angela H.; Berger, Shelley L.; Cerrato, Flavia; Riccio, Andrea; Bartolomei, Marisa S.

    2016-01-01

    Genomic imprinting affects a subset of genes in mammals, such that they are expressed in a monoallelic, parent-of-origin–specific manner. These genes are regulated by imprinting control regions (ICRs), cis-regulatory elements that exhibit allele-specific differential DNA methylation. Although genomic imprinting is conserved in mammals, ICRs are genetically divergent across species. This raises the fundamental question of whether the ICR plays a species-specific role in regulating imprinting at a given locus. We addressed this question at the H19/insulin-like growth factor 2 (Igf2) imprinted locus, the misregulation of which is associated with the human imprinting disorders Beckwith–Wiedemann syndrome (BWS) and Silver–Russell syndrome (SRS). We generated a knock-in mouse in which the endogenous H19/Igf2 ICR (mIC1) is replaced by the orthologous human ICR (hIC1) sequence, designated H19hIC1. We show that hIC1 can functionally replace mIC1 on the maternal allele. In contrast, paternally transmitted hIC1 leads to growth restriction, abnormal hIC1 methylation, and loss of H19 and Igf2 imprinted expression. Imprint establishment at hIC1 is impaired in the male germ line, which is associated with an abnormal composition of histone posttranslational modifications compared with mIC1. Overall, this study reveals evolutionarily divergent paternal imprinting at IC1 between mice and humans. The conserved maternal imprinting mechanism and function at IC1 demonstrates the possibility of modeling maternal transmission of hIC1 mutations associated with BWS in mice. In addition, we propose that further analyses in the paternal knock-in H19+/hIC1 mice will elucidate the molecular mechanisms that may underlie SRS. PMID:27621468

  20. Characterization of the IGF2 Imprinted Gene Methylation Status in Bovine Oocytes during Folliculogenesis.

    PubMed

    Mendonça, Anelise dos Santos; Guimarães, Ana Luíza Silva; da Silva, Naiara Milagres Augusto; Caetano, Alexandre Rodrigues; Dode, Margot Alves Nunes; Franco, Maurício Machaim

    2015-01-01

    DNA methylation reprogramming occurs during mammalian gametogenesis and embryogenesis. Sex-specific DNA methylation patterns at specific CpG islands controlling imprinted genes are acquired during this window of development. Characterization of the DNA methylation dynamics of imprinted genes acquired by oocytes during folliculogenesis is essential for understanding the physiological and genetic aspects of female gametogenesis and to determine the parameters for oocyte competence. This knowledge can be used to improve in vitro embryo production (IVP), specifically because oocyte competence is one of the most important aspects determining the success of IVP. Imprinted genes, such as IGF2, play important roles in embryo development, placentation and fetal growth. The aim of this study was to characterize the DNA methylation profile of the CpG island located in IGF2 exon 10 in oocytes during bovine folliculogenesis. The methylation percentages in oocytes from primordial follicles, final secondary follicles, small antral follicles, large antral follicles, MII oocytes and spermatozoa were 73.74 ± 2.88%, 58.70 ± 7.46%, 56.00 ± 5.58%, 65.77 ± 5.10%, 56.35 ± 7.45% and 96.04 ± 0.78%, respectively. Oocytes from primordial follicles showed fewer hypomethylated alleles (15.5%) than MII oocytes (34.6%) (p = 0.039); spermatozoa showed only hypermethylated alleles. Moreover, MII oocytes were less methylated than spermatozoa (p<0.001). Our results showed that the methylation pattern of this region behaves differently between mature oocytes and spermatozoa. However, while this region has a classical imprinted pattern in spermatozoa that is fully methylated, it was variable in mature oocytes, showing hypermethylated and hypomethylated alleles. Furthermore, our results suggest that this CpG island may have received precocious reprogramming, considering that the hypermethylated pattern was already found in growing oocytes from primordial follicles. These results may contribute to

  1. The IGF2 Locus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Insulin-like growth factor 2 (IGF2) is a peptide hormone regulating various cellular processes such as proliferation and apoptosis. IGF2 is vital to embryo development. The IGF2 locus covers approximately 150-kb genomic region on human chromosome 11, containing two imprinted genes, IGF2 and H19, sha...

  2. Gene therapy for colorectal cancer by adenovirus-mediated siRNA targeting CD147 based on loss of the IGF2 imprinting system.

    PubMed

    Pan, Yuqin; He, Bangshun; Chen, Jie; Sun, Huiling; Deng, Qiwen; Wang, Feng; Ying, Houqun; Liu, Xian; Lin, Kang; Peng, Hongxin; Xie, Hongguang; Wang, Shukui

    2015-11-01

    Colorectal cancer (CRC) is one of the most common malignant tumors worldwide. Loss of imprinting (LOI) of the insulin-like growth factor 2 (IGF2) gene is an epigenetic abnormality phenomenon in CRC. Recently observed association of CRC with cluster of differentiation 147 (CD147) could provide a novel approach for gene therapy. In the present study, we investigated the feasibility of using adenovirus‑mediated siRNA targeting CD147 based on the IGF2 LOI system for targeted gene therapy of CRC. A novel adenovirus-mediated siRNA targeting CD147, rAd-H19-CD147mirsh, which was driven by the IGF2 imprinting system, was constructed. The results showed that the EGFP expression was detected only in the IGF2 LOI cell lines (HT-29 and HCT-8), but that no EGFP was produced in cell lines with maintenance of imprinting (MOI) (HCT116). Moreover, rAd-H19-CD147mirsh significantly inhibited the expression of CD147, decreased cell viability and invasive ability, and increased sensitivity to chemotherapeutic drugs only in the LOI cell lines in vitro. Furthermore, mice bearing HT-29 xenografted tumors, which received intratumoral administration of the rAd-H19-CD147mirsh, showed significantly reduced tumor growth and enhanced survival. We conclude that recombinant adenovirus-mediated siRNA targeting CD147 based on the IGF2 LOI system inhibited the growth of the LOI cells in vitro and in vivo, which would provide a novel approach for targeted CRC gene therapy.

  3. Genomic Imprinting of the M6P/IGF2 Receptor: A Novel Breast Cancer Susceptibility Mechanism

    DTIC Science & Technology

    2000-07-01

    embryonic growth and development. They also are involved in cancer because their functional haploid state makes them vulnerable to being either inactivated or...Breast Cancer, Genomic Imprinting, M6P/IGF2R, Tumor Suppressor, 7 Imprinting Evolution I_16._PRICECODE 16. PRICE CODE 17. SECURITY CLASSIFICATION 18...tissues not available for our analysis. However, recent experimental evidence from our laboratory, based on a detailed analysis of the evolution of

  4. Identification of transgenic cloned dairy goats harboring human lactoferrin and methylation status of the imprinted gene IGF2R in their lungs.

    PubMed

    Zhang, Y L; Zhang, G M; Wan, Y J; Jia, R X; Li, P Z; Han, L; Wang, F; Huang, M R

    2015-09-22

    Dairy goat is a good model for production of transgenic proteins in milk using somatic cell nuclear transfer (SCNT). However, animals produced from SCNT are often associated with lung deficiencies. We recently produced six transgenic cloned dairy goats harboring the human lactoferrin gene, including three live transgenic clones and three deceased transgenic clones that died from respiratory failure during the perinatal period. Imprinted genes are important regulators of lung growth, and may be subjected to faulty reprogramming. In the present study, first, microsatellite analysis, PCR, and DNA sequence identification were conducted to confirm that these three dead kids were genetically identical to the transgenic donor cells. Second, the CpG island methylation profile of the imprinted insulin-like growth factor receptor (IGF2R) gene was assessed in the lungs of the three dead transgenic kids and the normally produced kids using bisulfite sequencing PCR. In addition, the relative mRNA level of IGF2R was also determined by real-time PCR. Results showed that the IGF2R gene in the lungs of the dead cloned kids showed abnormal hypermethylation and higher mRNA expression levels than the control, indicating that aberrant DNA methylation reprogramming is one of the important factors in the death of transgenic cloned animals.

  5. IGF2 — EDRN Public Portal

    Cancer.gov

    IGF2 is a member of the insulin family of polypeptide growth factors that is involved in development and growth. The IGF2 gene is an imprinted gene and is expressed only from the paternally inherited allele. It is a candidate gene for eating disorders. There is a read-through, INS-IGF2, which aligns to this gene at the 3' region and to the upstream INS gene at the 5' region. Alternatively spliced transcript variants, encoding either the same or different isoform, have been found for this gene. IGF2 is influenced by placental lactogen and may play a role in fetal development.

  6. In vitro lead exposure changes DNA methylation and expression of IGF2 and PEG1/MEST.

    PubMed

    Nye, Monica D; Hoyo, Cathrine; Murphy, Susan K

    2015-04-01

    Epigenetic processes, such as changes in DNA methylation, likely mediate the link between environmental exposures in utero and altered gene expression. Differentially methylated regions (DMRs) that regulate imprinted genes may be especially vulnerable to environmental exposures since imprinting is established and maintained largely through DNA methylation, resulting in expression from only one parental chromosome. We used the human embryonic kidney cell line, HEK-293, to investigate the effects of exposure to physiologically relevant doses of lead acetate (Pb) on the methylation status of nine imprinted gene DMRs. We assessed mean methylation after seventy-two hours of Pb exposure (0-25 μg/dL) using bisulfite pyrosequencing. The PEG1/MEST and IGF2 DMRs had maximum methylation decreases of 9.6% (20 μg/dL; p<0.005) and 3.8% (25 μg/dL; p<0.005), respectively. Changes at the MEG3 DMRs had a maximum decrease in methylation of 2.9% (MEG3) and 1.8% (MEG3-IG) at 5 μg/dL Pb, but were not statistically significant. The H19, NNAT, PEG3, PLAGL1, and SGCE/PEG10 DMRs showed a less than 0.5% change in methylation, across the dose range used, and were deemed non-responsive to Pb in our model. Pb exposure below reportable/actionable levels increased expression of PEG1/MEST concomitant with decreased methylation. These results suggest that Pb exposure can stably alter the regulatory capacity of multiple imprinted DMRs.

  7. LOI of IGF2 is associated with esophageal cancer and linked to methylation status of IGF2 DMR.

    PubMed

    Xu, W; Fan, H; He, X; Zhang, J; Xie, W

    2006-12-01

    In the present study, IGF2 mRNA expression was examined by semi-quantitative RT-PCR in 46 esophageal cancer cases. LOI of IGF2 was detected in informative samples, which were determined as heterozygote with ApaI polymorphism in exon 9 of IGF2 by PCR-RFLP and RT-PCR-RFLP. Methylation status of IGF2 DMR in informative samples was analyzed by sodium bisulfite treatment and PCR and the following cloning sequencing. The results showed that there was over-expression of IGF2 mRNA in tumor tissues (T) compared to their matched normal tissues (N) (P < 0.05). The expression level of IGF2 in tumor tissues was associated with pathological grades (P < 0.05), but proved irrelevant to clinical stages (P > 0.05). Of all informative samples, 21% (5/24) of cases showed there were IGF2 LOI; however, there was IGF2 LOI in the tumor tissue and not in its matched normal tissue in a special case. Methylation level of IGF2 DMR was average 29.7% in normal imprinting samples and 50.6% (P < 0.01) in IGF2 LOI separate samples. These data suggested that IGF2 may participate in carcinogenesis of esophageal cancer through its over-expression. IGF2 LOI may be one of the factors that lead to overexpression of IGF2 and may be at least partly due to aberrant methylation of IGF2 DMR in esophageal cancer.

  8. Tissue-specific and minor inter-individual variation in imprinting of IGF2R is a common feature of Bos taurus Concepti and not correlated with fetal weight.

    PubMed

    Bebbere, Daniela; Bauersachs, Stefan; Fürst, Rainer W; Reichenbach, Horst-Dieter; Reichenbach, Myriam; Medugorac, Ivica; Ulbrich, Susanne E; Wolf, Eckhard; Ledda, Sergio; Hiendleder, Stefan

    2013-01-01

    The insulin-like growth factor 2 receptor (IGF2R) is essential for prenatal growth regulation and shows gene dosage effects on fetal weight that can be affected by in-vitro embryo culture. Imprinted maternal expression of murine Igf2r is well documented for all fetal tissues excluding brain, but polymorphic imprinting and biallelic expression were reported for IGF2R in human. These differences have been attributed to evolutionary changes correlated with specific reproductive strategies. However, data from species suitable for testing this hypothesis are lacking. The domestic cow (Bos taurus) carries a single conceptus with a similar gestation length as human. We identified 12 heterozygous concepti informative for imprinting studies among 68 Bos taurus fetuses at Day 80 of gestation (28% term) and found predominantly maternal IGF2R expression in all fetal tissues but brain, which escapes imprinting. Inter-individual variation in allelic expression bias, i.e. expression of the repressed paternal allele relative to the maternal allele, ranged from 4.6-8.9% in heart, 4.3-10.2% in kidney, 6.1-11.2% in liver, 4.6-15.8% in lung and 3.2-12.2% in skeletal muscle. Allelic bias for mesodermal tissues (heart, skeletal muscle) differed significantly (P<0.05) from endodermal tissues (liver, lung). The placenta showed partial imprinting with allelic bias of 22.9-34.7% and differed significantly (P<0.001) from all other tissues. Four informative fetuses were generated by in-vitro fertilization (IVF) with embryo culture and two individuals displayed fetal overgrowth. However, there was no evidence for changes in imprinting or DNA methylation after IVF, or correlations between allelic bias and fetal weight. In conclusion, imprinting of Bos taurus IGF2R is similar to mouse except in placenta, which could indicate an effect of reproductive strategy. Common minor inter-individual variation in allelic bias and absence of imprinting abnormalities in IVF fetuses suggest changes in IGF2R

  9. Embryonic IGF2 Expression Is Not Associated with Offspring Size among Populations of a Placental Fish

    PubMed Central

    Schrader, Matthew; Travis, Joseph

    2012-01-01

    In organisms that provision young between fertilization and birth, mothers and their developing embryos are expected to be in conflict over embryonic growth. In mammalian embryos, the expression of Insulin-like growth factor II (IGF2) plays a key role in maternal-fetal interactions and is thought to be a focus of maternal-fetal conflict. Recent studies have suggested that IGF2 is also a focus of maternal-fetal conflict in placental fish in the family Poeciliidae. However, whether the expression of IGF2 influences offspring size, the trait over which mothers and embryos are likely to be in conflict, has not been assessed in a poeciliid. We tested whether embryonic IGF2 expression varied among four populations of a placental poeciliid that display large and consistent differences in offspring size at birth. We found that IGF2 expression varied significantly among embryonic stages with expression being 50% higher in early stage embryos than late stage embryos. There were no significant differences among populations in IGF2 expression; small differences in expression between population pairs with different offspring sizes were comparable in magnitude to those between population pairs with the same offspring sizes. Our results indicate that variation in IGF2 transcript abundance does not contribute to differences in offspring size among H. formosa populations. PMID:23029026

  10. Intragenic DNA methylation status down-regulates bovine IGF2 gene expression in different developmental stages.

    PubMed

    Huang, Yong-Zhen; Zhan, Zhao-Yang; Sun, Yu-Jia; Cao, Xiu-Kai; Li, Ming-Xun; Wang, Jing; Lan, Xian-Yong; Lei, Chu-Zhao; Zhang, Chun-Lei; Chen, Hong

    2014-01-25

    DNA methylation is a key epigenetic modification in mammals and has an essential and important role in muscle development. Insulin-like growth factor 2 (IGF2) is a fetal growth and differentiation factor that plays an important role in muscle growth and in myoblast proliferation and differentiation. The aim of this study was to evaluate the expression of IGF2 and the methylation pattern on the differentially methylated region (DMR) of the last exon of IGF2 in six tissues with two different developmental stages. The DNA methylation pattern was compared using bisulfite sequencing polymerase chain reaction (BSP) and combined bisulfite restriction analysis (COBRA). The quantitative real-time PCR (qPCR) analysis indicated that IGF2 has a broad tissue distribution and the adult bovine group showed significant lower mRNA expression levels than that in the fetal bovine group (P<0.05 or P<0.01). Moreover, the DNA methylation level analysis showed that the adult bovine group exhibited a significantly higher DNA methylation levels than that in the fetal bovine group (P<0.05 or P<0.01). These results indicate that IGF2 expression levels were negatively associated with the methylation status of the IGF2 DMR during the two developmental stages. Our results suggest that the methylation pattern in this DMR may be a useful parameter to investigate as a marker-assisted selection for muscle developmental in beef cattle breeding program and as a model for studies in other species.

  11. IGF2 expression is a marker for paraganglionic/SIF cell differentiation in neuroblastoma.

    PubMed Central

    Hedborg, F.; Ohlsson, R.; Sandstedt, B.; Grimelius, L.; Hoehner, J. C.; Pählman, S.

    1995-01-01

    Neuroblastoma is a childhood tumor of the sympathetic nervous system. Observations in the Beckwith-Wiedemann syndrome suggest that sympathetic embryonal cells with an abundant expression of the insulin-like growth factor 2 gene (IGF2) may be involved in the genesis of low-malignant infant neuroblastomas. We have therefore compared the cell type-specific IGF2 expression of the human sympathetic nervous system during early development with that of neuroblastoma. An abundant expression in normal sympathetic tissue was specific to extra-adrenal chromaffin cells, ie, paraganglia and small intensely fluorescent (SIF) cells, whereas sympathetic neuronal cells were IGF2-negative. A subpopulation of neuroblastomas expressed IGF2, which correlated with an early age at diagnosis, an extra-adrenal tumor origin, and severe hemodynamic signs of catecholamine secretion. Histologically IGF2-expressing tumors displayed a lobular growth pattern, and expression was restricted to the most mature and least proliferative cells. Typically, these cells were morphologically and histochemically similar to paraganglia/SIF cells and formed distinct ring-like zones in the center of the lobules around a core of apoptosis-like tumor cells. The similarities found between IGF2-expressing neuroblastoma cells and paraganglia/SIF cells in terms of histological features, anatomical origin, and age-dependent growth suggest a paraganglionic/SIF cell lineage of most infant tumors and also of extra-adrenal tumors diagnosed after infancy. Furthermore, since paraganglia/SIF cells undergo postnatal involution, the same cellular mechanism may be responsible for spontaneous regression in infant neuroblastoma. Images Figure 2 Figure 3 p839-a Figure 4 PMID:7717451

  12. Complete Biallelic Insulation at the H19/Igf2 Imprinting Control Region Position Results in Fetal Growth Retardation and Perinatal Lethality

    PubMed Central

    Lee, Dong-Hoon; Singh, Purnima; Tsark, Walter M. K.; Szabó, Piroska E.

    2010-01-01

    Background The H19/Igf2 imprinting control region (ICR) functions as an insulator exclusively in the unmethylated maternal allele, where enhancer-blocking by CTCF protein prevents the interaction between the Igf2 promoter and the distant enhancers. DNA methylation inhibits CTCF binding in the paternal ICR allele. Two copies of the chicken β-globin insulator (ChβGI)2 are capable of substituting for the enhancer blocking function of the ICR. Insulation, however, now also occurs upon paternal inheritance, because unlike the H19 ICR, the (ChβGI)2 does not become methylated in fetal male germ cells. The (ChβGI)2 is a composite insulator, exhibiting enhancer blocking by CTCF and chromatin barrier functions by USF1 and VEZF1. We asked the question whether these barrier proteins protected the (ChβGI)2 sequences from methylation in the male germ line. Methodology/Principal Findings We genetically dissected the ChβGI in the mouse by deleting the binding sites USF1 and VEZF1. The methylation of the mutant versus normal (ChβGI)2 significantly increased from 11% to 32% in perinatal male germ cells, suggesting that the barrier proteins did have a role in protecting the (ChβGI)2 from methylation in the male germ line. Contrary to the H19 ICR, however, the mutant (mChβGI)2 lacked the potential to attain full de novo methylation in the germ line and to maintain methylation in the paternal allele in the soma, where it consequently functioned as a biallelic insulator. Unexpectedly, a stricter enhancer blocking was achieved by CTCF alone than by a combination of the CTCF, USF1 and VEZF1 sites, illustrated by undetectable Igf2 expression upon paternal transmission. Conclusions/Significance In this in vivo model, hypomethylation at the ICR position together with fetal growth retardation mimicked the human Silver-Russell syndrome. Importantly, late fetal/perinatal death occurred arguing that strict biallelic insulation at the H19/Igf2 ICR position is not tolerated in development

  13. Transcription factor ZBED6 mediates IGF2 gene expression by regulating promoter activity and DNA methylation in myoblasts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Zinc finger, BED-type containing 6 (ZBED6) is an important transcription factor in placental mammals, affecting development, cell proliferation and growth. In this study, we found that the expression of the ZBED6 and IGF2 were up regulated during C2C12 differentiation. The IGF2 expression levels wer...

  14. Dietary supplementation with polyunsaturated fatty acid during pregnancy modulates DNA methylation at IGF2/H19 imprinted genes and growth of infants

    PubMed Central

    Lee, Ho-Sun; Barraza-Villarreal, Albino; Biessy, Carine; Duarte-Salles, Talita; Sly, Peter D.; Ramakrishnan, Usha; Rivera, Juan; Herceg, Zdenko

    2014-01-01

    Epigenetic regulation of imprinted genes is regarded as a highly plausible explanation for linking dietary exposures in early life with the onset of diseases during childhood and adulthood. We sought to test whether prenatal dietary supplementation with docosahexaenoic acid (DHA) during pregnancy may modulate epigenetic states at birth. This study was based on a randomized intervention trial conducted in Mexican pregnant women supplemented daily with 400 mg of DHA or a placebo from gestation week 18–22 to parturition. We applied quantitative profiling of DNA methylation states at IGF2 promoter 3 (IGF2 P3), IGF2 differentially methylated region (DMR), and H19 DMR in cord blood mononuclear cells of the DHA-supplemented group (n = 131) and the control group (n = 130). In stratified analyses, DNA methylation levels in IGF2 P3 were significantly higher in the DHA group than the control group in preterm infants (P = 0.04). We also observed a positive association between DNA methylation levels and maternal body mass index; IGF2 DMR methylation was higher in the DHA group than the control group in infants of overweight mothers (P = 0.03). In addition, at H19 DMR, methylation levels were significantly lower in the DHA group than the control group in infants of normal weight mothers (P = 0.01). Finally, methylation levels at IGF2/H19 imprinted regions were associated with maternal BMI. These findings suggest that epigenetic mechanisms may be modulated by DHA, with potential impacts on child growth and development. PMID:25293351

  15. CTCF-dependent chromatin bias constitutes transient epigenetic memory of the mother at the H19-Igf2 imprinting control region in prospermatogonia.

    PubMed

    Lee, Dong-Hoon; Singh, Purnima; Tsai, Shirley Y; Oates, Nathan; Spalla, Alexander; Spalla, Claudio; Brown, Lucy; Rivas, Guillermo; Larson, Garrett; Rauch, Tibor A; Pfeifer, Gerd P; Szabó, Piroska E

    2010-11-24

    Genomic imprints-parental allele-specific DNA methylation marks at the differentially methylated regions (DMRs) of imprinted genes-are erased and reestablished in germ cells according to the individual's sex. Imprint establishment at paternally methylated germ line DMRs occurs in fetal male germ cells. In prospermatogonia, the two unmethylated alleles exhibit different rates of de novo methylation at the H19/Igf2 imprinting control region (ICR) depending on parental origin. We investigated the nature of this epigenetic memory using bisulfite sequencing and allele-specific ChIP-SNuPE assays. We found that the chromatin composition in fetal germ cells was biased at the ICR between the two alleles with the maternally inherited allele exhibiting more H3K4me3 and less H3K9me3 than the paternally inherited allele. We determined genetically that the chromatin bias, and also the delayed methylation establishment in the maternal allele, depended on functional CTCF insulator binding sites in the ICR. Our data suggest that, in primordial germ cells, maternally inherited allele-specific CTCF binding sets up allele-specific chromatin differences at the ICR. The erasure of these allele-specific chromatin marks is not complete before the process of de novo methylation imprint establishment begins. CTCF-dependent allele-specific chromatin composition imposes a maternal allele-specific delay on de novo methylation imprint establishment at the H19/Igf2 ICR in prospermatogonia.

  16. An isocorydine derivative (d-ICD) inhibits drug resistance by downregulating IGF2BP3 expression in hepatocellular carcinoma

    PubMed Central

    Ge, Chao; Chen, Lijuan; Fang, Tao; Li, Hong; Tian, Hua; Liu, Junxi; Chen, Taoyang; Jiang, Guoping; Xie, Haiyang; Cui, Ying; Yao, Ming; Li, Jinjun

    2015-01-01

    In our previous studies, we reported that CD133+ cancer stem cells (CSCs) were chemoresistant in hepatocellular carcinoma (HCC) and that isocorydine treatment decreased the percentage of CD133+ CSCs. Here, we found that a derivative of isocorydine (d-ICD) inhibited HCC cell growth, particularly among the CD133+ subpopulation, and rendered HCC cells more sensitive to sorafenib treatment. d-ICD inhibited IGF2BP3 expression in a time-dependent manner, and IGF2BP3 expression negatively correlated with d-ICD-induced growth suppression. IGF2BP3 overexpression enriched the CD133+ CSC subpopulation in HCC, enhanced tumor sphere formation and suppressed the cytotoxic effects of sorafenib and doxorubicin. The expression of drug resistance-related genes, including ABCB1 and ABCG2, and the CSC marker CD133 expression was increased after IGF2BP3 overexpression. The significance of these observations was underscored by our findings that high IGF2BP3 expression predicted poor survival in a cohort of 236 patients with HCC and positively correlated with ABCG2 and CD133 expression in vivo. These results suggested that the d-ICD may inhibit HCC cells growth by IGF2BP3 decrease and that IGF2BP3 may serve as a therapeutic target for HCC. PMID:26327240

  17. Increased hepatic Igf2 gene expression involves C/EBPβ in TCDD-induced teratogenesis in rats.

    PubMed

    Wang, Jun; Liu, Xiaoliang; Li, Tingting; Liu, Caixia; Zhao, Yanyan

    2011-11-01

    2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a widespread environmental contaminant for reproductive toxicity that was suggested to be linked to growth factors. Insulin-like growth factor 2 (Igf2) has great effects on the control of fetal growth. We hypothesize it might participate in the TCDD-induced toxic events. The expression of Igf2 in TCDD-induced fetal rat and rat hepatoma BRL-3A cells was monitored by real-time quantitative RT-PCR and Western blotting. Electrophoresis mobility shift assay and chromatin immunoprecipitation were performed to identify the CCAAT/enhancer binding protein β (C/EBPβ) responsive element in the Igf2 P3-promoter. The transcriptional activity of the Igf2 P3-promoter was detected by luciferase assay. Pregnant rats exposed to TCDD showed a modest incidence of fetal death, fetal growth restriction and fetal malformation. The levels of Igf2 mRNA and IGF2 protein were elevated in TCDD-exposed fetal liver. Temporal expression of Igf2 was also induced by TCDD in BRL-3A cells. A C/EBPβ responsive element was identified at position -743 to -732 of the Igf2 P3-promoter, and its binding was enhanced by TCDD exposure through upregulation of the C/EBPβ protein. The transcriptional activity of the Igf2 P3-promoter was also augmented by TCDD. Our results showed that TCDD may induce Igf2 gene expression through the transactivation of C/EBPβ, which may be linked to the developmental effects of TCDD in rats.

  18. Transcription Factor ZBED6 Mediates IGF2 Gene Expression by Regulating Promoter Activity and DNA Methylation in Myoblasts

    NASA Astrophysics Data System (ADS)

    Huang, Yong-Zhen; Zhang, Liang-Zhi; Lai, Xin-Sheng; Li, Ming-Xun; Sun, Yu-Jia; Li, Cong-Jun; Lan, Xian-Yong; Lei, Chu-Zhao; Zhang, Chun-Lei; Zhao, Xin; Chen, Hong

    2014-04-01

    Zinc finger, BED-type containing 6 (ZBED6) is an important transcription factor in placental mammals, affecting development, cell proliferation and growth. In this study, we found that the expression of the ZBED6 and IGF2 were upregulated during C2C12 differentiation. The IGF2 expression levels were negatively associated with the methylation status in beef cattle (P < 0.05). A luciferase assay for the IGF2 intron 3 and P3 promoter showed that the mutant-type 439 A-SNP-pGL3 in driving reporter gene transcription is significantly higher than that of the wild-type 439 G-SNP-pGL3 construct (P < 0.05). An over-expression assay revealed that ZBED6 regulate IGF2 expression and promote myoblast differentiation. Furthermore, knockdown of ZBED6 led to IGF2 expression change in vitro. Taken together, these results suggest that ZBED6 inhibits IGF2 activity and expression via a G to A transition disrupts the interaction. Thus, we propose that ZBED6 plays a critical role in myogenic differentiation.

  19. Enhanced sensitivity to IGF-II signaling links loss of imprinting of IGF2 to increased cell proliferation and tumor risk.

    PubMed

    Kaneda, Atsushi; Wang, Chiaochun J; Cheong, Raymond; Timp, Winston; Onyango, Patrick; Wen, Bo; Iacobuzio-Donahue, Christine A; Ohlsson, Rolf; Andraos, Rita; Pearson, Mark A; Sharov, Alexei A; Longo, Dan L; Ko, Minoru S H; Levchenko, Andre; Feinberg, Andrew P

    2007-12-26

    Loss of imprinting (LOI) of the insulin-like growth factor-II gene (IGF2), leading to abnormal activation of the normally silent maternal allele, is a common human epigenetic population variant associated with a 5-fold increased frequency of colorectal neoplasia. Here, we show first that LOI leads specifically to increased expression of proliferation-related genes in mouse intestinal crypts. Surprisingly, LOI(+) mice also have enhanced sensitivity to IGF-II signaling, not simply increased IGF-II levels, because in vivo blockade with NVP-AEW541, a specific inhibitor of the IGF-II signaling receptor, showed reduction of proliferation-related gene expression to levels half that seen in LOI(-) mice. Signal transduction assays in microfluidic chips confirmed this enhanced sensitivity with marked augmentation of Akt/PKB signaling in LOI(+) cells at low doses of IGF-II, which was reduced in the presence of the inhibitor to levels below those found in LOI(-) cells, and was associated with increased expression of the IGF1 and insulin receptor genes. We exploited this increased IGF-II sensitivity to develop an in vivo chemopreventive strategy using the azoxymethane (AOM) mutagenesis model. LOI(+) mice treated with AOM showed a 60% increase in premalignant aberrant crypt foci (ACF) formation over LOI(-) mice. In vivo IGF-II blockade with NVP-AEW541 abrogated this effect, reducing ACF to a level 30% lower even than found in exposed LOI(-) mice. Thus, LOI increases cancer risk in a counterintuitive way, by increasing the sensitivity of the IGF-II signaling pathway itself, providing a previously undescribed epigenetic chemoprevention strategy in which cells with LOI are "IGF-II addicted" and undergo reduced tumorigenesis in the colon upon IGF-II pathway blockade.

  20. Enhanced sensitivity to IGF-II signaling links loss of imprinting of IGF2 to increased cell proliferation and tumor risk

    PubMed Central

    Kaneda, Atsushi; Wang, Chiaochun J.; Cheong, Raymond; Timp, Winston; Onyango, Patrick; Wen, Bo; Iacobuzio-Donahue, Christine A.; Ohlsson, Rolf; Andraos, Rita; Pearson, Mark A.; Sharov, Alexei A.; Longo, Dan L.; Ko, Minoru S. H.; Levchenko, Andre; Feinberg, Andrew P.

    2007-01-01

    Loss of imprinting (LOI) of the insulin-like growth factor-II gene (IGF2), leading to abnormal activation of the normally silent maternal allele, is a common human epigenetic population variant associated with a 5-fold increased frequency of colorectal neoplasia. Here, we show first that LOI leads specifically to increased expression of proliferation-related genes in mouse intestinal crypts. Surprisingly, LOI(+) mice also have enhanced sensitivity to IGF-II signaling, not simply increased IGF-II levels, because in vivo blockade with NVP-AEW541, a specific inhibitor of the IGF-II signaling receptor, showed reduction of proliferation-related gene expression to levels half that seen in LOI(−) mice. Signal transduction assays in microfluidic chips confirmed this enhanced sensitivity with marked augmentation of Akt/PKB signaling in LOI(+) cells at low doses of IGF-II, which was reduced in the presence of the inhibitor to levels below those found in LOI(−) cells, and was associated with increased expression of the IGF1 and insulin receptor genes. We exploited this increased IGF-II sensitivity to develop an in vivo chemopreventive strategy using the azoxymethane (AOM) mutagenesis model. LOI(+) mice treated with AOM showed a 60% increase in premalignant aberrant crypt foci (ACF) formation over LOI(−) mice. In vivo IGF-II blockade with NVP-AEW541 abrogated this effect, reducing ACF to a level 30% lower even than found in exposed LOI(−) mice. Thus, LOI increases cancer risk in a counterintuitive way, by increasing the sensitivity of the IGF-II signaling pathway itself, providing a previously undescribed epigenetic chemoprevention strategy in which cells with LOI are “IGF-II addicted” and undergo reduced tumorigenesis in the colon upon IGF-II pathway blockade. PMID:18087038

  1. Overexpression of IGF2R and IGF1R mRNA in SCNT-produced goats survived to adulthood.

    PubMed

    Xing, Baosong; Xu, Yinxue; Cheng, Yong; Liu, Honglin; Du, Miao

    2007-08-01

    The procedure of somatic cell nuclear transfer (SCNT) is likely to affect the expression level of growth-related genes especially imprinting genes. In this study, expressions of growth-related genes including three imprinting genes (H19, IGF2, and IGF2R) and four non-imprinting genes (IGF1, IGF1R, GHR, and GHSR) in adult nuclear transferred (NT) goats were investigated by real-time PCR. The expressions of these genes in adult clones were found largely normal, but IGF2R and IGF1R were more highly expressed in cloned goats than in non-NT goats (P < 0.01). Analysis on mono-allelic expression pattern of imprinting genes indicated that mono-allelic expression patterns of H19 and IGF2 in cloned goats were similar to that in non-NT goats. In addition, the sequence of goat IGF2 gene and the putative amino acid sequence were obtained. The 986 nucleotide cDNA of goat IGF2 gene contained an open-reading frame of 540 nucleotides coding for 179 amino acids. Both cDNA sequence and amino acid sequence of IGF2 in goat showed their higher homology with that in sheep than in cattle; the partial cDNA fragments of H19, IGF2R, GHSR, IGF1R, and GHR in goat were also cloned and sequenced, which shared higher sequence identities with those in sheep than in cattle.

  2. Genotype-Epigenotype Interaction at the IGF2 DMR.

    PubMed

    Murphy, Susan K; Erginer, Erin; Huang, Zhiqing; Visco, Zachary; Hoyo, Cathrine

    2015-08-28

    Paternally expressed Insulin-like Growth Factor II (IGF2) encodes a gene whose protein product functions as a potent growth mitogen. Overexpression of IGF2 has been implicated in a wide number of disorders and diseases. IGF2 is regulated in part by differential methylation of the two parentally derived alleles. The differentially methylated region (DMR) located upstream of the imprinted promoters of IGF2 exhibits plasticity under environmental stress and is hypomethylated in several types of cancer. Through bisulfite pyrosequencing and confirmation by nucleotide sequencing, we discovered a CpG to CpC transversion that results in hypomethylation of one of the three CpGs comprising this DMR. The presence of the polymorphism introduces a genetic rather than an environmentally-driven epigenetic source of hypomethylation that is additive to non-genetic sources.

  3. ZBED6, a Novel Transcription Factor Derived from a Domesticated DNA Transposon Regulates IGF2 Expression and Muscle Growth

    PubMed Central

    Jaffe, Jacob D.; Mikkelsen, Tarjei S.; Wallerman, Ola; Larhammar, Martin; Zhang, Xiaolan; Wang, Li; Saenz-Vash, Veronica; Gnirke, Andreas; Lindroth, Anders M.; Barrés, Romain; Yan, Jie; Strömberg, Sara; De, Sachinandan; Pontén, Fredrik; Lander, Eric S.; Carr, Steven A.; Zierath, Juleen R.; Kullander, Klas; Wadelius, Claes; Lindblad-Toh, Kerstin; Andersson, Göran; Hjälm, Göran; Andersson, Leif

    2009-01-01

    A single nucleotide substitution in intron 3 of IGF2 in pigs abrogates a binding site for a repressor and leads to a 3-fold up-regulation of IGF2 in skeletal muscle. The mutation has major effects on muscle growth, size of the heart, and fat deposition. Here, we have identified the repressor and find that the protein, named ZBED6, is previously unknown, specific for placental mammals, and derived from an exapted DNA transposon. Silencing of Zbed6 in mouse C2C12 myoblasts affected Igf2 expression, cell proliferation, wound healing, and myotube formation. Chromatin immunoprecipitation (ChIP) sequencing using C2C12 cells identified about 2,500 ZBED6 binding sites in the genome, and the deduced consensus motif gave a perfect match with the established binding site in Igf2. Genes associated with ZBED6 binding sites showed a highly significant enrichment for certain Gene Ontology classifications, including development and transcriptional regulation. The phenotypic effects in mutant pigs and ZBED6-silenced C2C12 myoblasts, the extreme sequence conservation, its nucleolar localization, the broad tissue distribution, and the many target genes with essential biological functions suggest that ZBED6 is an important transcription factor in placental mammals, affecting development, cell proliferation, and growth. PMID:20016685

  4. Abnormal expression of DNA methyltransferases and genomic imprinting in cloned goat fibroblasts.

    PubMed

    Wan, Yongjie; Deng, Mingtian; Zhang, Guomin; Ren, Caifang; Zhang, Hao; Zhang, Yanli; Wang, Lizhong; Wang, Feng

    2016-01-01

    Somatic cell nuclear transfer (SCNT) is a useful way to produce cloned animals. However, SCNT animals exhibit DNA methylation and genomic imprinting abnormalities. These abnormalities may be due to the faulty epigenetic reprogramming of donor cells. To investigate the consequence of SCNT on the genomic imprinting and global methylation in the donor cells, growth patterns and apoptosis of cloned goat fibroblast cells (CGFCs) at passage 7 were determined. Growth patterns in CGFCs were similar to the controls; however, the growth rate in log phase was lower and apoptosis in CGFCs were significantly higher (P < 0.01). In addition, quantitative expression analysis of three DNA methyltransferases (Dnmt) and two imprinted genes (H19, IGF2R) was conducted in CGFCs: Dnmt1 and Dnmt3b expression was significantly reduced (P < 0.01), and H19 expression was decreased sixfold (P < 0.01); however, the expression of Dnmt3a was unaltered and IGF2R expression was significantly increased (P < 0.05). Finally, we used bisulfite sequencing PCR to compare the DNA methylation patterns in differentially methylated regions (DMRs) of H19 and IGF2R. The DMRs of H19 (P < 0.01) and IGF2R (P < 0.01) were both highly methylated in CGFCs. These results indicate that the global genome might be hypomethylated. Moreover, there is an aberrant expression of imprinted genes and DMR methylation in CGFCs.

  5. Genomic Imprinting of the M6P/IGF2 Receptor: A Novel Breast Cancer Susceptibility Mechanism

    DTIC Science & Technology

    1999-07-01

    function are best exemplified by studies on Wilms’ tumor, a will be required to determine whether this provocative sporadic and familial childhood kidney...an abnormal in over 20 different tumor types, demonstrating its nurturing behavior. It is presently unknown whether fundamental mechanistic importance...in carcinogene- PEG11MEST inactivation has a similar effect on ma- sis [9]. ternal nurturing behavior in humans or what effect Another imprinted gene

  6. HMGA1P7-pseudogene regulates H19 and Igf2 expression by a competitive endogenous RNA mechanism

    PubMed Central

    De Martino, Marco; Forzati, Floriana; Marfella, Marianna; Pellecchia, Simona; Arra, Claudio; Terracciano, Luigi; Fusco, Alfredo; Esposito, Francesco

    2016-01-01

    Recent studies have revealed that pseudogene transcripts can function as competing endogenous RNAs, and thereby can also contribute to cancer when dysregulated. We have recently identified two pseudogenes, HMGA1P6 and HMGA1P7 for the HMGA1 gene whose overexpression has a critical role in cancer progression. These pseudogenes work as competitive endogenous RNA decoys for HMGA1 and other cancer related genes suggesting their role in carcinogenesis. Looking for new HMGA1 pseudogene ceRNAs, we performed RNA sequencing technology on mouse embryonic fibroblasts deriving from transgenic mice overexpressing HMGA1P7. Here, we report that HMGA1P7 mRNA sustains the H19 and Igf2 overexpression by acting as miRNA decoy. Lastly, the expression of HMGA1P7 was significantly correlated with H19 and IGF2 levels in human breast cancer thereby suggesting a role for HMGA1P7 deregulation in this neoplasia. PMID:27874091

  7. Faithful expression of imprinted genes in donor cells of SCNT cloned pigs.

    PubMed

    Wang, Dongxu; Yuan, Lin; Sui, Tingting; Song, Yuning; Lv, Qingyan; Wang, Anfeng; Li, Zhanjun; Lai, Liangxue

    2015-07-22

    To understand if the genomic imprinting status of the donor cells is altered during the process of SCNT (somatic cell nuclear transfer), cloned pigs were produced by SCNT using PEF (porcine embryonic fibroblast) and P-PEF (parthenogenetic-PEF) cells as donors. Then, the gene expression and methylation patterns of H19, IGF2, NNAT and MEST were compared between PEF vs. C-PEF (cloned-PEF), P-PEF vs. CP-PEF (cloned-P-PEF), respectively. Taken together, the results revealed that there was no significant difference in the expression of imprinted genes and conserved genomic imprints between the donor and cloned cells.

  8. Analysis of imprinted messenger RNA expression in deceased transgenic cloned goats.

    PubMed

    Jia, R X; Zhou, Z R; Zhang, G M; Wang, L Z; Fan, Y X; Wan, Y J; Zhang, Y L; Wang, Z Y; Wang, F

    2016-01-29

    Genomic imprinting is an important epigenetic mechanism that has vital effects on fetal growth and development. We observed the differences in four tissues (heart, spleen, liver, and kidney) from dead transgenic cloned goats using hematoxylin and eosin (H&E) staining. Eight imprinted genes in the tissues of dead transgenic cloned and normal goats were analyzed using reverse transcription polymerase chain reaction. H&E staining results from the abortion group indicated the lack of obvious morphological changes in heart and spleen tissues, while inflammatory cell infiltration and glomerular nephritis characteristics were observed in liver and kidney tissues, respectively. Compared to the control group, CDKN1C, H19, IGF2R, and SNRPN were significantly (P < 0.05) overexpressed in the heart tissue of the abortion group, while XIST was significantly reduced. In the liver tissues, CDKN1C and DLK1 expression decreased, while GNAS, H19, IGF2R, PEG3, and XIST expression increased significantly. In the spleen tissues, DLK1 expression increased, while GNAS, H19, IGF2R, PEG3, SNRPN, and XIST expression decreased. In the kidney tissues, CDKN1C, DLK1, GNAS, IGF2R, and PEG3 expression increased, while H19 and XIST expression decreased. The overall expression of imprinted genes was abnormal in different tissues of transgenic cloned goats, and the degree of abnormal genomic imprinting was more severe in the abortion group compared to the death and control groups. These results suggest that abnormal expression of imprinted genes may cause developmental defects in transgenic cloned goats. Moreover, abnormal epigenetic modifications may affect the reprogramming of transgenic donor cells.

  9. Allelic gene expression imbalance of bovine IGF2, LEP and CCL2 genes in liver, kidney and pituitary.

    PubMed

    Olbromski, R; Siadkowska, E; Zelazowska, B; Zwierzchowski, L

    2013-02-01

    Allelic expression imbalance (AEI) is an important genetic factor being the cause of differences in phenotypic traits that can be heritable. Studying AEI can be useful in searching for factors that modulate gene expression and help to understand molecular mechanisms underlying phenotypic changes. Although it was commonly recognized in many species and we know many genes show allelic expression imbalance, this phenomena was not studied on a larger scale in cattle. Using the pyrosequencing method we analyzed a set of 29 bovine genes in order to find those that have preferential allelic expression. The study was conducted in three tissues: liver, pituitary and kindey. Out of the studied group of genes 3 of them-LEP (leptin), IGF2 (insulin-like growth factor 2), CCL2 (chemokine C-C motif ligand 2) showed allelic expression imbalance.

  10. Embryos aggregation improves development and imprinting gene expression in mouse parthenogenesis.

    PubMed

    Bai, Guang-Yu; Song, Si-Hang; Wang, Zhen-Dong; Shan, Zhi-Yan; Sun, Rui-Zhen; Liu, Chun-Jia; Wu, Yan-Shuang; Li, Tong; Lei, Lei

    2016-04-01

    Mouse parthenogenetic embryonic stem cells (PgESCs) could be applied to study imprinting genes and are used in cell therapy. Our previous study found that stem cells established by aggregation of two parthenogenetic embryos at 8-cell stage (named as a2 PgESCs) had a higher efficiency than that of PgESCs, and the paternal expressed imprinting genes were observably upregulated. Therefore, we propose that increasing the number of parthenogenetic embryos in aggregation may improve the development of parthenogenetic mouse and imprinting gene expression of PgESCs. To verify this hypothesis, we aggregated four embryos together at the 4-cell stage and cultured to the blastocyst stage (named as 4aPgB). qPCR detection showed that the expression of imprinting genes Igf2, Mest, Snrpn, Igf2r, H19, Gtl2 in 4aPgB were more similar to that of fertilized blastocyst (named as fB) compared to 2aPgB (derived from two 4-cell stage parthenogenetic embryos aggregation) or PgB (single parthenogenetic blastocyst). Post-implantation development of 4aPgB extended to 11 days of gestation. The establishment efficiency of GFP-a4 PgESCs which derived from GFP-4aPgB is 62.5%. Moreover, expression of imprinting genes Igf2, Mest, Snrpn, notably downregulated and approached the level of that in fertilized embryonic stem cells (fESCs). In addition, we acquired a 13.5-day fetus totally derived from GFP-a4 PgESCs with germline contribution by 8-cell under zona pellucida (ZP) injection. In conclusion, four embryos aggregation improves parthenogenetic development, and compensates imprinting genes expression in PgESCs. It implied that a4 PgESCs could serve as a better scientific model applied in translational medicine and imprinting gene study.

  11. Effect of developmental dioxin exposure on methylation and expression of specific imprinted genes in mice.

    PubMed

    Somm, Emmanuel; Stouder, Christelle; Paoloni-Giacobino, Ariane

    2013-01-01

    2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is an endocrine disruptor affecting the reproductive system in humans. The aim of this study was to evaluate the effects of TCDD administered to pregnant mice at two different doses (2-10 ng/kg/day), on imprinted genes in the male offspring. The degree of methylation and the mRNA expression of Snrpn, Peg3 and Igf2r were analyzed in the sperm, skeletal muscle and liver. TCDD administration (10 ng/kg/day) decreased the sperm count in the male offspring. It did not affect methylation but increased mRNA expression of Snrpn, Peg3, Igf2r and Air ncRNA. In muscle and liver, TCDD (10 ng/kg/day) induced increases in methylation and decreases in mRNA expression of Igf2r. These results show that the robust effects of TCDD on the mRNA expression of Snrpn, Peg3 and Igf2r genes in the sperm and of Igf2r in the muscle and liver are unrelated to changes in methylation in their respective genes.

  12. Induced DNA demethylation can reshape chromatin topology at the IGF2-H19 locus

    PubMed Central

    Ito, Yoko; Nativio, Raffaella; Murrell, Adele

    2013-01-01

    Choriocarcinomas are embryonal tumours with loss of imprinting and hypermethylation at the insulin-like growth factor 2 (IGF2)-H19 locus. The DNA methyltransferase inhibitor, 5-Aza-2′deoxycytidine (5-AzaCdR) is an approved epigenetic cancer therapy. However, it is not known to what extent 5-AzaCdR influences other epigenetic marks. In this study, we set out to determine whether 5-AzaCdR treatment can reprogram the epigenomic organization of the IGF2-H19 locus in a choriocarcinoma cancer cell line (JEG3). We found that localized DNA demethylation at the H19 imprinting control region (ICR) induced by 5-AzaCdR, reduced IGF2, increased H19 expression, increased CTCF and cohesin recruitment and changed histone modifications. Furthermore chromatin accessibility was increased locus-wide and chromatin looping topography was altered such that a CTCF site downstream of the H19 enhancers switched its association with the CTCF site upstream of the IGF2 promoters to associate with the ICR. We identified a stable chromatin looping domain, which forms independently of DNA methylation. This domain contains the IGF2 gene and is marked by a histone H3 lysine 27 trimethylation block between CTCF site upstream of the IGF2 promoters and the Centrally Conserved Domain upstream of the ICR. Together, these data provide new insights into the responsiveness of chromatin topography to DNA methylation changes. PMID:23585276

  13. Retrograde fibroblast growth factor 22 (FGF22) signaling regulates insulin-like growth factor 2 (IGF2) expression for activity-dependent synapse stabilization in the mammalian brain

    PubMed Central

    Terauchi, Akiko; Johnson-Venkatesh, Erin M; Bullock, Brenna; Lehtinen, Maria K; Umemori, Hisashi

    2016-01-01

    Communication between pre- and postsynaptic cells promotes the initial organization of synaptic specializations, but subsequent synaptic stabilization requires transcriptional regulation. Here we show that fibroblast growth factor 22 (FGF22), a target-derived presynaptic organizer in the mouse hippocampus, induces the expression of insulin-like growth factor 2 (IGF2) for the stabilization of presynaptic terminals. FGF22 is released from CA3 pyramidal neurons and organizes the differentiation of excitatory nerve terminals formed onto them. Local application of FGF22 on the axons of dentate granule cells (DGCs), which are presynaptic to CA3 pyramidal neurons, induces IGF2 in the DGCs. IGF2, in turn, localizes to DGC presynaptic terminals and stabilizes them in an activity-dependent manner. IGF2 application rescues presynaptic defects of Fgf22-/- cultures. IGF2 is dispensable for the initial presynaptic differentiation, but is required for the following presynaptic stabilization both in vitro and in vivo. These results reveal a novel feedback signal that is critical for the activity-dependent stabilization of presynaptic terminals in the mammalian hippocampus. DOI: http://dx.doi.org/10.7554/eLife.12151.001 PMID:27083047

  14. Ox-LDL Upregulates IL-6 Expression by Enhancing NF-κB in an IGF2-Dependent Manner in THP-1 Macrophages.

    PubMed

    Wang, Yan-Chao; Hu, Yan-Wei; Sha, Yan-Hua; Gao, Ji-Juan; Ma, Xin; Li, Shu-Fen; Zhao, Jia-Yi; Qiu, Yu-Rong; Lu, Jing-Bo; Huang, Chuan; Zhao, Jing-Jing; Zheng, Lei; Wang, Qian

    2015-12-01

    Interleukin 6 (IL-6) is a pro-inflammatory cytokine that is well established as a vital factor in determining the risk of coronary heart disease and pathogenesis of atherosclerosis. Moreover, accumulating evidences have shown that oxidized low-density lipoprotein (ox-LDL) can promote IL-6 expression in macrophages. Nevertheless, the underlying mechanism of how ox-LDL upregulates IL-6 expression remains largely unexplained. We found that the expression of insulin-like growth factor 2 (IGF2), nuclear factor kappa B (NF-κB), and IL-6 was upregulated at both the messenger RNA (mRNA) and protein levels in a dose-dependent manner when treated with 0, 25, 50, or 100 μg/mL of ox-LDL for 48 h in THP-1 macrophages. Moreover, overexpression of IGF2 significantly upregulated NF-κB and IL-6 expressions in THP-1 macrophages. However, the upregulation of NF-κB and IL-6 expressions induced by ox-LDL were significantly abolished by IGF2 small interfering RNA (siRNA) in THP-1 macrophages. Further studies indicated the upregulation of IL-6 induced by ox-LDL could be abolished when treated with NF-κB siRNA in THP-1 macrophages. Ox-LDL might upregulate IL-6 in the cell and its secretion via enhancing NF-κB in an IGF2-dependent manner in THP-1 macrophages.

  15. Restricted development of mouse triploid fetuses with disorganized expression of imprinted genes.

    PubMed

    Yamazaki, Wataru; Takahashi, Masashi; Kawahara, Manabu

    2015-12-01

    Eukaryotic species commonly contain a diploid complement of chromosomes. The diploid state appears to be advantageous for mammals because it enables sexual reproduction and facilitates genetic recombination. Nonetheless, the effects of DNA ploidy on mammalian ontogeny have yet to be understood. The present study shows phenotypic features and expression patterns of imprinted genes in tripronucleate diandric and digynic triploid (DAT and DGT) mouse fetuses on embryonic day 10.5 (E10.5). Measurement of crown-rump length revealed that the length of DGT fetuses (1.87 ± 0.13 mm; mean ± standard error of the mean) was much smaller than that of diploid fetuses (4.81 ± 0.05 mm). However, no significant difference was observed in the crown-rump length between diploid and DAT fetuses (3.86 ± 0.43 mm). In DGT fetuses, the expression level of paternally expressed genes, Igf2, Dlk1, Ndn, and Peg3, remained significantly reduced and that of maternally expressed genes, Igf2r and Grb10, increased. Additionally, in DAT fetuses, the Igf2 mRNA expression level was approximately twice that in diploid fetuses, as expected. These results provide the first demonstration that imprinted genes in mouse triploid fetuses show distinctive expression patterns independent of the number of parental-origin haploid sets. These data suggest that both DNA ploidy and asymmetrical functions of parental genomes separately influence mammalian ontogeny.

  16. Decreased IDE and IGF2 expression but increased Aβ40 in the cerebral cortex of mouse pups by early life lead exposure.

    PubMed

    Li, Ning; Yang, Guojun; Wang, Yueying; Qiao, Mingwu; Zhang, Pingan; Shao, Jianfeng; Yang, Guoyu

    2016-03-01

    As the abbreviation of plumbum and a chemical symbol for lead, Pb produces neurotoxic effects, which result into an impairment of learning and memory and other neurological dysfunctions. However, the mechanism of neurotoxicity of Pb exposure is unclear. The present study was undertaken to investigate the effects of maternal lead exposure on expression of insulin-degrading enzyme (IDE),insulin-like growth factor 2 (IGF2) and beta amyloid protein 40 (Aβ40) in the cerebral cortex of mice offspring. Lead exposure initiated from beginning of gestation to weaning. Lead acetate administered in drinking solutions was dissolved in distilled deionized water at the concentrations of 0.1%, 0.2% and 0.5% groups respectively. On the 21st postnatal day, On the PND21, the learning and memory ability were tested by water maze test and the Pb levels were also determined by graphite furnace atomic absorption spectrometry. The expression of IDE, IGF2 and Aβ40 in cerebral cortex was examined by immunohistochemistry, immunofluorescence and western blotting. The lead levels in blood and cerebral cortex of all lead exposure groups were significantly higher than that of the control group (P<0.05). In water maze test, the performances of 0.5% and 1% lead exposure groups were worse than that of the control group (P<0.05).The expression of IDE and IGF2 was decreased, but Aβ40 was increased in lead exposed groups than that of the control group (P<0.05). The decreased expression of IDE and IGF2 and increased expression of Aβ40 in the cerebral cortex of pups may contribute to the neurotoxicity associated with maternal Pb exposure.

  17. 11p15 ICR1 Partial Deletions Associated with IGF2/H19 DMR Hypomethylation and Silver-Russell Syndrome.

    PubMed

    Abi Habib, Walid; Brioude, Frederic; Azzi, Salah; Salem, Jennifer; Das Neves, Cristina; Personnier, Claire; Chantot-Bastaraud, Sandra; Keren, Boris; Le Bouc, Yves; Harbison, Madeleine D; Netchine, Irene

    2017-01-01

    The 11p15 region harbors the IGF2/H19 imprinted domain, implicated in fetal and postnatal growth. Silver-Russell syndrome (SRS) is characterized by fetal and postnatal growth failure, and is caused principally by hypomethylation of the 11p15 imprinting control region 1 (ICR1). However, the mechanisms leading to ICR1 hypomethylation remain unknown. Maternally inherited genetic defects affecting the ICR1 domain have been associated with ICR1 hypermethylation and Beckwith-Wiedemann syndrome (an overgrowth syndrome, the clinical and molecular mirror of SRS), and paternal deletions of IGF2 enhancers have been detected in four SRS patients. However, no paternal deletions of ICR1 have ever been associated with hypomethylation of the IGF2/H19 domain in SRS. We screened for new genetic defects within the ICR1 in a cohort of 234 SRS patients with hypomethylated IGF2/H19 domain. We report deletions close to the boundaries of ICR1 on the paternal allele in one familial and two sporadic cases of SRS with ICR1 hypomethylation. These deletions are associated with hypomethylation of the remaining CBS, and decreased IGF2 expression. These results suggest that these regions are most likely required to maintain methylation after fertilization. We estimate these anomalies to occur in about 1% of SRS cases with ICR1 hypomethylation.

  18. [Imprinting genes and it's expression in Arabidopsis].

    PubMed

    Zhang, Hong-Yu; Xu, Pei-Zhou; Yang, Hua; Wu, Xian-Jun

    2010-07-01

    Genomic imprinting refers to the phenomenon that the expression of a gene copy depends on its parent of origin. The Arabidopsis imprinted FIS (Fertilisation-independent seed) genes, mea, fis2, and fie, play essential roles in the repression of central cell and the regulation of early endosperm development. fis mutants display two phenotypes: autonomous diploid endosperm development when fertilization is absent and un-cellularised endosperm formation when fertilization occurs. The FIS Polycomb protein complex including the above three FIS proteins catalyzes histone H3 K27 tri-methylation on target loci. DME (DEMETER), a DNA glycosylase, and AtMET1 (Methyltransferase1), a DNA methyltransferase, are involved in the regulation of imprinted expression of both mea and fis2. This review summarizes the studies on the Arabidopsis imprinted FIS genes and other related genes. Recent works have shown that the insertion of transposons may affect nearby gene expression, which may be the main driving force behind the evolution of genomic imprinting. This summary covers the achievements on Arabidopsis imprinted genes will provide important information for studies on genomic imprinting in the important crops such as rice and maize.

  19. Copy number variations alter methylation and parallel IGF2 overexpression in adrenal tumors

    PubMed Central

    Nielsen, Helene Myrtue; How-Kit, Alexandre; Guerin, Carole; Castinetti, Frederic; Vollan, Hans Kristian Moen; De Micco, Catherine; Daunay, Antoine; Taieb, David; Van Loo, Peter; Besse, Celine; Kristensen, Vessela N; Hansen, Lise Lotte; Barlier, Anne; Sebag, Frederic; Tost, Jörg

    2015-01-01

    Overexpression of insulin growth factor 2 (IGF2) is a hallmark of adrenocortical carcinomas and pheochromocytomas. Previous studies investigating the IGF2/H19 locus have mainly focused on a single molecular level such as genomic alterations or altered DNA methylation levels and the causal changes underlying IGF2 overexpression are still not fully established. In the current study, we analyzed 62 tumors of the adrenal gland from patients with Conn's adenoma (CA, n=12), pheochromocytomas (PCC, n=10), adrenocortical benign tumors (ACBT, n=20), and adrenocortical carcinomas (ACC, n=20). Gene expression, somatic copy number variation of chr11p15.5, and DNA methylation status of three differential methylated regions of the IGF2/H19 locus including the H19 imprinting control region were integratively analyzed. IGF2 overexpression was found in 85% of the ACCs and 100% of the PCCs compared to 23% observed in CAs and ACBTs. Copy number aberrations of chr11p15.5 were abundant in both PCCs and ACCs but while PCCs retained a diploid state, ACCs were frequently tetraploid (7/19). Loss of either a single allele or loss of two alleles of the same parental origin in tetraploid samples resulted in a uniparental disomy-like genotype. These copy number changes correlated with hypermethylation of the H19 ICR suggesting that the lost alleles were the unmethylated maternal alleles. Our data provide conclusive evidence that loss of the maternal allele correlates with IGF2 overexpression in adrenal tumors and that hypermethylation of the H19 ICR is a consequence thereof. PMID:26400872

  20. Differential expression of imprinted genes in normal and IUGR human placentas.

    PubMed

    Diplas, Andreas I; Lambertini, Luca; Lee, Men-Jean; Sperling, Rhoda; Lee, Yin Leng; Wetmur, James; Chen, Jia

    2009-05-16

    Genomic imprinting refers to silencing of one parental allele in the zygotes of gametes depending upon the parent of origin. Loss of imprinting (LOI) is the gain of function from the silent allele that can have a maximum effect of doubling the gene dosage. LOI may play a significant role in the etiology of intrauterine growth restriction (IUGR). Using placental tissue from ten normal and seven IUGR pregnancies, we conducted a systematic survey of the expression of a panel of 74 "putatively" imprinted genes using quantitative RT-PCR. We found that 52/74 ( approximately 70%) of the genes were expressed in human placentas. Nine of the 52 (17%) expressed genes were significantly differentially expressed between normal and IUGR placentas; five were upregulated (PHLDA2, ILK2, NNAT, CCDC86, PEG10) and four downregulated (PLAGL1, DHCR24, ZNF331, CDKAL1). We also assessed LOI profile of 14 imprinted genes in 14 normal and 24 IUGR placentas using a functional and sensitive assay developed in our laboratory. Little LOI was observed in any placentas for five of the genes (PEG10, PHLDA2, MEG3, EPS15, CD44). With the 149 heterozygosities examined, 40 (26.8%) exhibited LOI >3%. Some genes exhibited frequent LOI in placentas regardless of the disease status (IGF2, TP73, MEST, SLC22A18, PEG3), while others exhibited LOI only in IUGR placentas (PLAGL1, DLK1, H19, SNRPN). Importantly, there was no correlation between gene expression and LOI profile. Our study suggests that genomic imprinting may play a role in IUGR pathogenesis, but mechanisms other than LOI may contribute to dysregulation of imprinted genes.

  1. Butyrate induced IGF2 activation correlated with distinct chromatin landscapes due to histone modification

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Histone modification has emerged as a very important mechanism regulating the transcriptional status of the genome. Insulin-like growth factor 2 (IGF2) is a peptide hormone controlling various cellular processes such as proliferation and apoptosis. IGF2 and H19 are reciprocally regulated imprinted ...

  2. Effects of endocrine disruptors on imprinted gene expression in the mouse embryo.

    PubMed

    Kang, Eun-Rim; Iqbal, Khursheed; Tran, Diana A; Rivas, Guillermo E; Singh, Purnima; Pfeifer, Gerd P; Szabó, Piroska E

    2011-07-01

    Environmental endocrine disruptors (EDs) are synthetic chemicals that resemble natural hormones and are known to cause epigenetic perturbations. EDs have profound effects on development and fertility. Imprinted genes had been identified as susceptible loci to environmental insults by EDs because they are functionally haploid, and because the imprints undergo epigenetic resetting between generations. To screen for possible epigenetic perturbations caused by EDs at imprinted loci, we treated pregnant mice daily between 8.5 and 12.5 days post coitum (dpc) with di-(2-ethylhexyl)-phthalate (DEHP), bisphenol A (BPA), vinclozolin (VZ), or control oil vehicle. After isolating RNA from the placenta, yolk sac, amnion, head, body, heart, liver, lung, stomach, and intestines of 13.5 dpc embryos we measured the allele-specific expression of 38 imprinted transcripts using multiplex single nucleotide primer extension (SNuPE) assays. In this representative data set we identified only a small number of transcripts that exhibited a substantial relaxation of imprinted expression with statistical significance: Slc22a18 with 10% relaxation in the embryo after BPA treatment; Rtl1as with 11 and 16% relaxation in the lung and placenta, respectively after BPA treatment; and Rtl1 with 12% relaxation in the yolk sac after DEHP treatment. Additionally, the standard deviation of allele-specificity increased in various organs after ED treatment for several transcripts including Igf2r, Rasgrf1, Usp29, Slc38a4, and Xist. Our data suggest that the maintenance of strongly biased monoallelic expression of imprinted genes is generally insensitive to EDs in the 13.5 dpc embryo and extra-embryonic organs, but is not immune to those effects.

  3. Addiction to the IGF2-ID1-IGF2 circuit for maintenance of the breast cancer stem-like cells

    PubMed Central

    Tominaga, K; Shimamura, T; Kimura, N; Murayama, T; Matsubara, D; Kanauchi, H; Niida, A; Shimizu, S; Nishioka, K; Tsuji, E-i; Yano, M; Sugano, S; Shimono, Y; Ishii, H; Saya, H; Mori, M; Akashi, K; Tada, K-i; Ogawa, T; Tojo, A; Miyano, S; Gotoh, N

    2017-01-01

    The transcription factor nuclear factor-κB (NF-κB) has important roles for tumorigenesis, but how it regulates cancer stem cells (CSCs) remains largely unclear. We identified insulin-like growth factor 2 (IGF2) is a key target of NF-κB activated by HER2/HER3 signaling to form tumor spheres in breast cancer cells. The IGF2 receptor, IGF1 R, was expressed at high levels in CSC-enriched populations in primary breast cancer cells. Moreover, IGF2-PI3K (IGF2-phosphatidyl inositol 3 kinase) signaling induced expression of a stemness transcription factor, inhibitor of DNA-binding 1 (ID1), and IGF2 itself. ID1 knockdown greatly reduced IGF2 expression, and tumor sphere formation. Finally, treatment with anti-IGF1/2 antibodies blocked tumorigenesis derived from the IGF1Rhigh CSC-enriched population in a patient-derived xenograft model. Thus, NF-κB may trigger IGF2-ID1-IGF2-positive feedback circuits that allow cancer stem-like cells to appear. Then, they may become addicted to the circuits. As the circuits are the Achilles' heels of CSCs, it will be critical to break them for eradication of CSCs. PMID:27546618

  4. Altered expression of the imprinted transcription factor PLAGL1 deregulates a network of genes in the human IUGR placenta

    PubMed Central

    Iglesias-Platas, Isabel; Martin-Trujillo, Alex; Petazzi, Paolo; Guillaumet-Adkins, Amy; Esteller, Manel; Monk, David

    2014-01-01

    Genomic imprinting is the epigenetic process that results in monoallelic expression of genes depending on parental origin. These genes are known to be critical for placental development and fetal growth in mammals. Aberrant epigenetic profiles at imprinted loci, such as DNA methylation defects, are surprisingly rare in pregnancies with compromised fetal growth, while variations in transcriptional output from the expressed alleles of imprinted genes are more commonly reported in pregnancies complicated with intrauterine growth restriction (IUGR). To determine if PLAGL1 and HYMAI, two imprinted transcripts deregulated in Transient Neonatal Diabetes Mellitus, are involved in non-syndromic IUGR we compared the expression and DNA methylation levels in a large cohort of placental biopsies from IUGR and uneventful pregnancies. This revealed that despite appropriate maternal methylation at the shared PLAGL1/HYMAI promoter, there was a loss of correlation between PLAGL1 and HYMAI expression in IUGR. This incongruity was due to higher HYMAI expression in IUGR gestations, coupled with PLAGL1 down-regulation in placentas from IUGR girls, but not boys. The PLAGL1 protein is a zinc-finger transcription factor that has been shown to be a master coordinator of a genetic growth network in mice. We observe PLAGL1 binding to the H19/IGF2 shared enhancers in placentae, with significant correlations between PLAGL1 levels with H19 and IGF2 expression levels. In addition, PLAGL1 binding and expression also correlate with expression levels of metabolic regulator genes SLC2A4, TCF4 and PPARγ1. Our results strongly suggest that fetal growth can be influenced by altered expression of the PLAGL1 gene network in human placenta. PMID:24993786

  5. The hepatic Igf2/H19 locus is not altered in 1-day old pups born to obese-prone Sprague-Dawley rats fed a low protein diet containing adequate folic acid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gong et al. (Epigenetics, 2010) found, using diets low in folic acid, that compared to an 18% protein diet a 9% protein diet fed to pregnant Sprague-Dawley rats resulted in increased Igf2 and H19 gene expression in the liver of day 0 male offspring. In addition DNA methylation in the Imprinting Cont...

  6. Genomic imprinting mechanisms in mammals.

    PubMed

    Ideraabdullah, Folami Y; Vigneau, Sebastien; Bartolomei, Marisa S

    2008-12-01

    Genomic imprinting is a form of epigenetic gene regulation that results in expression from a single allele in a parent-of-origin-dependent manner. This form of monoallelic expression affects a small but growing number of genes and is essential to normal mammalian development. Despite extensive studies and some major breakthroughs regarding this intriguing phenomenon, we have not yet fully characterized the underlying molecular mechanisms of genomic imprinting. This is in part due to the complexity of the system in that the epigenetic markings required for proper imprinting must be established in the germline, maintained throughout development, and then erased before being re-established in the next generation's germline. Furthermore, imprinted gene expression is often tissue or stage-specific. It has also become clear that while imprinted loci across the genome seem to rely consistently on epigenetic markings of DNA methylation and/or histone modifications to discern parental alleles, the regulatory activities underlying these markings vary among loci. Here, we discuss different modes of imprinting regulation in mammals and how perturbations of these systems result in human disease. We focus on the mechanism of genomic imprinting mediated by insulators as is present at the H19/Igf2 locus, and by non-coding RNA present at the Igf2r and Kcnq1 loci. In addition to imprinting mechanisms at autosomal loci, what is known about imprinted X-chromosome inactivation and how it compares to autosomal imprinting is also discussed. Overall, this review summarizes many years of imprinting research, while pointing out exciting new discoveries that further elucidate the mechanism of genomic imprinting, and speculating on areas that require further investigation.

  7. Genomic Imprinting Mechanisms in Mammals

    PubMed Central

    Ideraabdullah, Folami Y.; Vigneau, Sebastien; Bartolomei, Marisa S.

    2008-01-01

    Genomic imprinting is a form of epigenetic gene regulation that results in expression from a single allele in a parent-of-origin-dependent manner. This form of monoallelic expression affects a small but growing number of genes and is essential to normal mammalian development. Despite extensive studies and some major breakthroughs regarding this intriguing phenomenon, we have not yet fully characterized the underlying molecular mechanisms of genomic imprinting. This is in part due to the complexity of the system in that the epigenetic markings required for proper imprinting must be established in the germline, maintained throughout development, and then erased before being re-established in the next generation’s germline. Furthermore, imprinted gene expression is often tissue or stage-specific. It has also become clear that while imprinted loci across the genome seem to rely consistently on epigenetic markings of DNA methylation and/or histone modifications to discern parental alleles, the regulatory activities underlying these markings vary among loci. Here, we discuss different modes of imprinting regulation in mammals and how perturbations of these systems result in human disease. We focus mostly on the mechanism of genomic imprinting mediated by insulators as is present at the H19/Igf2 locus, and by non-coding RNA present at the Igf2r and Kcnq1 loci. In addition to imprinting mechanisms at autosomal loci, what is known about imprinted X-chromosome inactivation and how it compares to autosomal imprinting is also discussed. Overall, this review summarizes the many years of imprinting research, while pointing out exciting new discoveries that further elucidate the mechanism of genomic imprinting, and speculating on areas that require further investigation. PMID:18778719

  8. mRNA expression of CDH3, IGF2BP3, and BIRC5 in biliary brush cytology specimens is a useful adjunctive tool of cytology for the diagnosis of malignant biliary stricture

    PubMed Central

    Kim, Tae Ho; Chang, Jae Hyuck; Lee, Hee Jin; Kim, Jean A; Lim, Yeon Soo; Kim, Chang Whan; Han, Sok Won

    2016-01-01

    Abstract Although advances have been made in diagnostic tools, the distinction between malignant and benign biliary strictures still remains challenging. Intraductal brush cytology is a convenient and safe method that is used for the diagnosis of biliary stricture, but, low sensitivity limits its usefulness. This study aimed to demonstrate the usefulness of mRNA expression levels of target genes in brush cytology specimens combined with cytology for the diagnosis of malignant biliary stricture. Immunohistochemistry for cadherin 3 (CDH3), p53, insulin-like growth factor II mRNA-binding protein 3 (IGF2BP3), homeobox B7 (HOXB7), and baculoviral inhibitor of apoptosis repeat containing 5 (BIRC5) was performed in 4 benign and 4 malignant bile duct tissues. Through endoscopic or interventional radiologic procedures, brush cytology specimens were prospectively obtained in 21 and 35 paitents with biliary strictures. In the brush cytology specimens, the mRNA expressions levels of 5 genes were determined by real-time polymerase chain reaction. Immunohistochemistry for CDH3, p53, IGF2BP3, HOXB7, and BIRC5 all showed positive staining in malignant tissues in contrast to benign tissues, which were negative. In the brush cytology specimens, the mRNA expression levels of CDH3, IGF2BP3, HOXB7, and BIRC5 were significantly higher in cases of malignant biliary stricture compared with cases of benign stricture (P = 0.006, P < 0.001, P < 0.001, and P = 0.001). The receiver-operating characteristic curves of these 4 mRNAs demonstrated that mRNA expression levels are useful for the prediction of malignant biliary stricture (P = 0.006, P < 0.001, P < 0.001, and P = 0.002). The sensitivity and specificity, respectively, for malignant biliary stricture were 57.1% and 100% for cytology, 57.1% and 64.3% for CDH3, 76.2% and 100% for IGF2BP3, 71.4% and 57.1% for HOXB7, and 76.2% and 64.3% for BIRC5. When cytology was combined with the mRNA levels of CDH3, IGF2BP3, or BIRC5, the

  9. Epigenetic and genetic mechanisms of abnormal 11p15 genomic imprinting in Silver-Russell and Beckwith-Wiedemann syndromes.

    PubMed

    Demars, J; Le Bouc, Y; El-Osta, A; Gicquel, C

    2011-01-01

    Fetal growth is a complex process depending on the genetics of the fetus, the availability of nutrients to the fetus, maternal nutrition and various growth factors and hormones of maternal, fetal and placental origin. The IGF system, and more particularly IGF2, is one of the most important endocrine and paracrine growth systems regulating fetal and placental growth (reviewed in [1]). The IGF2 gene is regulated by genomic imprinting and is expressed only from the paternally-inherited allele in most tissues during fetal development and after birth. Imprinted genes are tightly regulated and are therefore particularly susceptible to changes, including environmental and nutritional changes. Dysregulation of a cluster of imprinted genes, including the IGF2 gene within the 11p15 region, results in two fetal growth disorders (Silver-Russell and Beckwith-Wiedemann syndromes) with opposite growth phenotypes. Those two syndromes are model imprinting disorders to decipher the regulation of genomic imprinting.

  10. IGF2/H19 hypomethylation in a patient with very low birthweight, preocious pubarche and insulin resistance

    PubMed Central

    2012-01-01

    Background Insulin like growth factor 2 (IGF2) is an imprinted gene, which has an important role in fetal growth as established in mice models. IGF2 is downregulated through hypomethylation of a differentially methylated region (DMR) in Silver Russell syndrome (SRS), characterised by growth restriction. We have previously reported that severe pre- and post-natal growth restriction associated with insulin resistance and precocious pubarche in a woman without body asymmetry or other SRS features resulted from a balanced translocation affecting the regulation of her IGF2 gene expression. We hypothesised that severe pre- and post-natal growth restriction associated with insulin resistance and precocious pubarche in the absence of SRS are also caused by downregulation of IGF2 through hypomethylation, gene mutation or structural chromosomal abnormalities. Methods We performed routine karyotyping, IGF2 gene sequencing and investigated DNA methylation of the IGF2 differentially methylated region (DMR)0 and H19 DMR using pyrosequencing, in four women selected for very low birth weight (<−3 SDS for gestational age), precocious pubarche, short adult stature (<−2 SDS), and insulin resistance (defined as HOMA-IS < 80%); and compared their methylation results to those of 95 control subjects. Results We identified a 20 year old woman with severe hypomethylation at both DMRs. She was the smallest at birth (birthweight SDS,-3.9), and had the shortest adult height (143 cm). The patient was diagnosed with polycystic ovarian syndrome at the age of 15 years, and had impaired fasting glucose in the presence of a low BMI (19.2 kg/m2). Conclusions Our case of growth restriction, premature pubarche and insulin resistance in the absence of body asymmetry or other features of SRS adds to the expanding phenotype of IGF2/H19 methylation abnormalities. Further studies are needed to confirm whether growth restriction in association with premature pubarche and insulin resistance

  11. Involvement of IGF-2, IGF-1R, IGF-2R and PTEN in development of human tooth germ - an immunohistochemical study.

    PubMed

    Kero, Darko; Cigic, Livia; Medvedec Mikic, Ivana; Galic, Tea; Cubela, Mladen; Vukojevic, Katarina; Saraga-Babic, Mirna

    2016-07-02

    Insulin-Like Growth Factor 2 (IGF-2) is a peptide hormone essential for prenatal growth and development. IGF-2 exerts its mitogenic effects via Insulin-Like Growth Factor 1 Receptor (IGF-1R), and is eliminated by binding to Insulin-Like Growth Receptor 2 (IGF-2R). IGF-2 is also negatively regulated by Phosphatase and Tensin Homolog (PTEN), a phosphatase mutated in various tumors. Not much is known about the interplay between these factors during human odontogenesis. In this study, expression patterns of IGF-2, IGF-1R, IGF-2R and PTEN were analyzed by double immunofluorescence in incisor human tooth germs during the foetal period of development between the 7(th) and 20(th) gestational week. Throughout the investigated period, IGF-2 was mostly expressed in enamel organ, whereas mild to moderate expression of PTEN could be seen in dental papilla and parts of enamel organ. Expression of IGF-1R was ubiquitous and displayed strong intensity throughout the entire enamel organ. In contrast, expression of IGF-2R had rather erratic pattern in enamel organ and dental papilla alike. Expression patterns of IGF-2, IGF-1R, IGF-2R and PTEN in highly proliferative cervical loops, as well as in differentiating pre-ameloblasts and pre-odontoblasts of cusp tip region during the early and late bell stages when enamel organ acquires definitive shape, indicate importance of these factors in crown morphogenesis of human incisor. Taken together, our data suggest the involvement of IGF-2, IGF-1R, IGF-2R and PTEN in temporo-spatial patterning of basic cellular processes (proliferation, differentiation) during normal tooth development. They are also relevant for improving knowledge of molecular basis of human odontogenesis.

  12. IGF2 DNA methylation is a modulator of newborn's fetal growth and development.

    PubMed

    St-Pierre, Julie; Hivert, Marie-France; Perron, Patrice; Poirier, Paul; Guay, Simon-Pierre; Brisson, Diane; Bouchard, Luigi

    2012-10-01

    The insulin-like growth factor 2 (IGF2) gene, located within a cluster of imprinted genes on chromosome 11p15, encodes a fetal and placental growth factor affecting birth weight. DNA methylation variability at the IGF2 gene locus has been previously reported but its consequences on fetal growth and development are still mostly unknown in normal pediatric population. We collected one hundred placenta biopsies from 50 women with corresponding maternal and cord blood samples and measured anthropometric indices, blood pressure and metabolic phenotypes using standardized procedures. IGF2/H19 DNA methylation and IGF2 circulating levels were assessed using sodium bisulfite pyrosequencing and ELISA, respectively. Placental IGF2 (DMR0 and DMR2) DNA methylation levels were correlated with newborn's fetal growth indices, such as weight, and with maternal IGF2 circulating concentration at the third trimester of pregnancy, whereas H19 (DMR) DNA methylation levels were correlated with IGF2 levels in cord blood. The maternal genotype of a known IGF2/H19 polymorphism (rs2107425) was associated with birth weight. Taken together, we showed that IGF2/H19 epigenotype and genotypes independently account for 31% of the newborn's weight variance. No association was observed with maternal diabetic status, glucose concentrations or prenatal maternal body mass index. This is the first study showing that DNA methylation at the IGF2/H19 genes locus may act as a modulator of IGF2 newborn's fetal growth and development within normal range. IGF2/H19 DNA methylation could represent a cornerstone in linking birth weight and fetal metabolic programming of late onset obesity.

  13. Aberrant genomic imprinting in rhesus monkey embryonic stem cells.

    PubMed

    Fujimoto, Akihisa; Mitalipov, Shoukhrat M; Kuo, Hung-Chih; Wolf, Don P

    2006-03-01

    Genomic imprinting involves modification of a gene or a chromosomal region that results in the differential expression of parental alleles. Disruption or inappropriate expression of imprinted genes is associated with several clinically significant syndromes and tumorigenesis in humans. Additionally, abnormal imprinting occurs in mouse embryonic stem cells (ESCs) and in clonally derived animals. Imprinted gene expression patterns in primate ESCs are largely unknown, despite the clinical potential of the latter in the cell-based treatment of human disease. Because of the possible implications of abnormal gene expression to cell or tissue replacement therapies involving ESCs, we examined allele specific expression of four imprinted genes in the rhesus macaque. Genomic and complementary DNA from embryos and ESC lines containing useful single nucleotide polymorphisms were subjected to polymerase chain reaction-based amplification and sequence analysis. In blastocysts, NDN expression was variable indicating abnormal or incomplete imprinting whereas IGF2 and SNRPN were expressed exclusively from the paternal allele and H19 from the maternal allele as expected. In ESCs, both NDN and SNRPN were expressed from the paternal allele while IGF2 and H19 showed loss of imprinting and biallelic expression. In differentiated ESC progeny, these expression patterns were maintained. The implications of aberrant imprinted gene expression to ESC differentiation in vitro and on ESC-derived cell function in vivo after transplantation are unknown.

  14. Curcumin inhibits urothelial tumor development by suppressing IGF2 and IGF2-mediated PI3K/AKT/mTOR signaling pathway.

    PubMed

    Tian, Binqiang; Zhao, Yingmei; Liang, Tao; Ye, Xuxiao; Li, Zuowei; Yan, Dongliang; Fu, Qiang; Li, Yonghui

    2017-03-26

    We have previously reported that curcumin inhibits urothelial tumor development in a rat bladder carcinogenesis model. In this study, we report that curcumin inhibits urothelial tumor development by suppressing IGF2 and IGF2-mediated PI3K/AKT/mTOR signaling pathway. Curcumin inhibits IGF2 expression at the transcriptional level and decreases the phosphorylation levels of IGF1R and IRS-1 in bladder cancer cells and N-methyl-N-nitrosourea (MNU)-induced urothelial tumor tissue. Ectopic expression of IGF2 and IGF1R, but not IGF1, in bladder cancer cells restored this process, suggesting that IGF2 is a target of curcumin. Moreover, introduction of constitutively active AKT1 abolished the inhibitory effect of curcumin on cell proliferation, migration, and restored the phosphorylation levels of 4E-BP1 and S6K1, suggesting that curcumin functions via suppressing IGF2-mediated AKT/mTOR signaling pathway. In summary, our results reveal that suppressing IGF2 and IGF2-mediated PI3K/AKT/mTOR signaling pathway is one of the mechanisms of action of curcumin. Our findings suggest a new therapeutic strategy against human bladder cancer caused by aberrant activation of IGF2, which are useful for translational application of curcumin.

  15. Imprinted gene expression in fetal growth and development.

    PubMed

    Lambertini, L; Marsit, C J; Sharma, P; Maccani, M; Ma, Y; Hu, J; Chen, J

    2012-06-01

    Experimental studies showed that genomic imprinting is fundamental in fetoplacental development by timely regulating the expression of the imprinted genes to overlook a set of events determining placenta implantation, growth and embryogenesis. We examined the expression profile of 22 imprinted genes which have been linked to pregnancy abnormalities that may ultimately influence childhood development. The study was conducted in a subset of 106 placenta samples, overrepresented with small and large for gestational age cases, from the Rhode Island Child Health Study. We investigated associations between imprinted gene expression and three fetal development parameters: newborn head circumference, birth weight, and size for gestational age. Results from our investigation show that the maternally imprinted/paternally expressed gene ZNF331 inversely associates with each parameter to drive smaller fetal size, while paternally imprinted/maternally expressed gene SLC22A18 directly associates with the newborn head circumference promoting growth. Multidimensional Scaling analysis revealed two clusters within the 22 imprinted genes which are independently associated with fetoplacental development. Our data suggest that cluster 1 genes work by assuring cell growth and tissue development, while cluster 2 genes act by coordinating these processes. Results from this epidemiologic study offer solid support for the key role of imprinting in fetoplacental development.

  16. Adaptation of nutrient supply to fetal demand in the mouse involves interaction between the Igf2 gene and placental transporter systems

    PubMed Central

    Constância, Miguel; Angiolini, Emily; Sandovici, Ionel; Smith, Paul; Smith, Rachel; Kelsey, Gavin; Dean, Wendy; Ferguson-Smith, Anne; Sibley, Colin P.; Reik, Wolf; Fowden, Abigail

    2005-01-01

    The mammalian fetus is unique in its dependence during gestation on the supply of maternal nutrients through the placenta. Maternal supply and fetal demand for nutrients need to be fine tuned for healthy growth and development of the fetus along its genetic trajectory. An altered balance between supply and demand can lead to deviations from this trajectory with long-term consequences for health. We have previously shown that in a knockout lacking the imprinted placental-specific Igf2 transcript (P0), growth of the placenta is compromised from early gestation but fetal growth is normal until late gestation, suggesting functional adaptation of the placenta to meet the fetal demands. Here, we show that placental transport of glucose and amino acids are increased in the Igf2 P0+/- null and that this up-regulation of transport occurs, at least in part, through increased expression of the transporter genes Slc2a3 and Slc38a4, the imprinted member of the System A amino acid transporter gene family. Decreasing fetal demand genetically by removal of fetal Igf2 abolished up-regulation of both transport systems and reduced placental System A amino acid transport activity and expression of Slc38a2 in late gestation. Our results provide direct evidence that the placenta can respond to fetal demand signals through regulation of expression of specific placental transport systems. Thus, crosstalk between an imprinted growth demand gene (Igf2) and placental supply transporter genes (Slc38a4, Slc38a2, and Slc2a3) may be a component of the genetic control of nutrient supply and demand during mammalian development. PMID:16365304

  17. Imprinted gene expression in hybrids: perturbed mechanisms and evolutionary implications.

    PubMed

    Wolf, J B; Oakey, R J; Feil, R

    2014-08-01

    Diverse mechanisms contribute to the evolution of reproductive barriers, a process that is critical in speciation. Amongst these are alterations in gene products and in gene dosage that affect development and reproductive success in hybrid offspring. Because of its strict parent-of-origin dependence, genomic imprinting is thought to contribute to the aberrant phenotypes observed in interspecies hybrids in mammals and flowering plants, when the abnormalities depend on the directionality of the cross. In different groups of mammals, hybrid incompatibility has indeed been linked to loss of imprinting. Aberrant expression levels have been reported as well, including imprinted genes involved in development and growth. Recent studies in humans emphasize that genetic diversity within a species can readily perturb imprinted gene expression and phenotype as well. Despite novel insights into the underlying mechanisms, the full extent of imprinted gene perturbation still remains to be determined in the different hybrid systems. Here we review imprinted gene expression in intra- and interspecies hybrids and examine the evolutionary scenarios under which imprinting could contribute to hybrid incompatibilities. We discuss effects on development and reproduction and possible evolutionary implications.

  18. Imprinted gene expression in hybrids: perturbed mechanisms and evolutionary implications

    PubMed Central

    Wolf, J B; Oakey, R J; Feil, R

    2014-01-01

    Diverse mechanisms contribute to the evolution of reproductive barriers, a process that is critical in speciation. Amongst these are alterations in gene products and in gene dosage that affect development and reproductive success in hybrid offspring. Because of its strict parent-of-origin dependence, genomic imprinting is thought to contribute to the aberrant phenotypes observed in interspecies hybrids in mammals and flowering plants, when the abnormalities depend on the directionality of the cross. In different groups of mammals, hybrid incompatibility has indeed been linked to loss of imprinting. Aberrant expression levels have been reported as well, including imprinted genes involved in development and growth. Recent studies in humans emphasize that genetic diversity within a species can readily perturb imprinted gene expression and phenotype as well. Despite novel insights into the underlying mechanisms, the full extent of imprinted gene perturbation still remains to be determined in the different hybrid systems. Here we review imprinted gene expression in intra- and interspecies hybrids and examine the evolutionary scenarios under which imprinting could contribute to hybrid incompatibilities. We discuss effects on development and reproduction and possible evolutionary implications. PMID:24619185

  19. Physical mapping of the IGF2 locus in the South American opossum Monodelphis domestica.

    PubMed

    Lawton, B R; Obergfell, C; O'Neill, R J; O'Neill, M J

    2007-01-01

    The South American opossum Monodelphis domestica has been a model organism for marsupials for many years and has recently been the subject of a large-scale genome sequencing effort that will provide the foundation for comparative studies of gene function and regulation. Genomic imprinting is one mechanism of gene regulation that has received increasing attention due to the impact of imprinting defects on development and disease. We have mapped the imprinted insulin-like growth factor II (IGF2) gene of M. domestica as a first step in understanding the regulatory mechanisms involved in genomic imprinting in this marsupial.

  20. GH indirectly enhances the regeneration of transgenic zebrafish fins through IGF2a and IGF2b.

    PubMed

    Nornberg, Bruna Félix; Almeida, Daniela Volcan; Figueiredo, Márcio Azevedo; Marins, Luis Fernando

    2016-10-01

    The somatotropic axis, composed essentially of the growth hormone (GH) and insulin-like growth factors (IGFs), is the main regulator of somatic growth in vertebrates. However, these protein hormones are also involved in various other major physiological processes. Although the importance of IGFs in mechanisms involving tissue regeneration has already been established, little is known regarding the direct effects of GH in these processes. In this study, we used a transgenic zebrafish (Danio rerio) model, which overexpresses GH from the beta-actin constitutive promoter. The regenerative ability of the caudal fin was assessed after repeated amputations, as well as the expression of genes related to the GH/IGF axis. The results revealed that GH overexpression increased the regenerated area of the caudal fin in transgenic fish after the second amputation. Transgenic fish also presented a decrease in gene expression of the GH receptor (ghrb), in opposition to the increased expression of the IGF1 receptors (igf1ra and igf1rb). These results suggest that transgenic fish have a higher sensitivity to IGFs than to GH during fin regeneration. With respect to the different IGFs produced locally, a decrease in igf1a expression and a significant increase in both igf2a and igf2b expression was observed, suggesting that igf1a is not directly involved in fin regeneration. Overall, the results revealed that excess GH enhances fin regeneration in zebrafish through igf2a and igf2b expression, acting indirectly on this major physiological process.

  1. Insulin-like growth factor (IGF) 2 stimulates steroidogenesis and mitosis of bovine granulosa cells through the IGF1 receptor: role of follicle-stimulating hormone and IGF2 receptor.

    PubMed

    Spicer, L J; Aad, P Y

    2007-07-01

    Little is known regarding the role of insulin-like growth factor 2 (IGF2) and the regulation of the IGF2 receptor (IGF2R) during follicular development. Granulosa cells were collected from small (1-5 mm) and large (8-22 mm) bovine follicles and were treated with IGF2 for 1-2 days in serum-free medium, and steroid production, cell proliferation, specific (125)I-IGF2 binding, and gene expression were quantified. IGF2 increased both estradiol and progesterone production by granulosa cells, and cells from large follicles were more responsive to the effects of IGF2 than those from small follicles. Abundance of aromatase (CYP19A1) mRNA was stimulated by IGF2 and IGF1. The effective dose (ED(50)) of IGF2 stimulating 50% of the maximal estradiol production was 63 ng/ml for small follicles and 12 ng/ml for large follicles, and these values were not affected by FSH. The ED(50) of IGF2 for progesterone production was 20 ng/ml for both small and large follicles. IGF2 also increased proliferation of granulosa cells by 2- to 3-fold, as determined by increased cell numbers and (3)H-thymidine incorporation into DNA. Treatment with IGF1R antibodies reduced the stimulatory effect of IGF2 and IGF1 on estradiol production and cell proliferation. Specific receptors for (125)I-IGF2 existed in granulosa cells, and 2-day treatment with estradiol, FSH, or cortisol had no significant effect on specific (125)I-IGF2 binding. Also, FSH treatment of small- and large-follicle granulosa cells had no effect on IGF2R mRNA levels, whereas IGF1 decreased IGF2R mRNA and specific (125)I-IGF2 binding. Granulosa cell IGF2R mRNA abundance was 3-fold greater in small than in large follicles. These findings support the hypothesis that both IGF2 and its receptor may play a role in granulosa cell function during follicular development. In particular, increased free IGF1 in developing follicles may decrease synthesis of IGF2R, thereby allowing for more IGF2 to be bioavailable (free) for induction of

  2. Maternal nutrition during pregnancy is associated with differential expression of imprinted genes and DNA methyltranfereases in muscle of beef cattle offspring.

    PubMed

    Wang, X; Lan, X; Radunz, A E; Khatib, H

    2015-01-01

    Maternal diet during pregnancy is a major determinant of the fetal developmental competence and may induce long-lasting epigenetic changes to the offspring. Imprinted genes have important roles in fetal programming, growth, and development. There are, however, limited data available on the influence of maternal diet on the expression of imprinted genes in beef cattle. Therefore, the objective of this study was to analyze the impact of maternal diet during pregnancy on the expression of 5 imprinted genes and 3 DNA methyltransferase genes in longissimus dorsi muscle from Angus calves. A total of 36 Angus-cross cows were inseminated to a single sire and on Day 135 of gestation they were randomly assigned to either low-starch (haylage) or high-starch (corn silage) diets. Diets were initially formulated to provide isocaloric and isonitrogenous intake. The H19, MEG8, IGF2R, and DNMT3a genes showed differential expression in longissimus dorsi muscle in calves between the diet groups. Given that high-starch diet is a source of energy for muscle growth and feed conversion efficiency in postnatal development, the mechanisms by which this diet affected expression of imprinted genes should be further explored.

  3. Parental imprinting regulates insulin-like growth factor signaling: a Rosetta Stone for understanding the biology of pluripotent stem cells, aging and cancerogenesis.

    PubMed

    Ratajczak, M Z; Shin, D-M; Schneider, G; Ratajczak, J; Kucia, M

    2013-04-01

    In recent years, solid evidence has accumulated that insulin-like growth factor-1 (IGF-1) and 2 (IGF-2) regulate many biological processes in normal and malignant cells. Recently, more light has been shed on the epigenetic mechanisms regulating expression of genes involved in IGF signaling (IFS) and it has become evident that these mechanisms are crucial for initiation of embryogenesis, maintaining the quiescence of pluripotent stem cells deposited in adult tissues (for example, very-small embryonic-like stem cells), the aging process, and the malignant transformation of cells. The expression of several genes involved in IFS is regulated at the epigenetic level by imprinting/methylation within differentially methylated regions (DMRs), which regulate their expression from paternal or maternal chromosomes. The most important role in the regulation of IFS gene expression is played by the Igf-2-H19 locus, which encodes the autocrine/paracrine mitogen IGF-2 and the H19 gene, which gives rise to a non-coding RNA precursor of several microRNAs that negatively affect cell proliferation. Among these, miR-675 has recently been demonstrated to downregulate expression of the IGF-1 receptor. The proper imprinting of DMRs at the Igf-2-H19 locus, with methylation of the paternal chromosome and a lack of methylation on the maternal chromosome, regulates expression of these genes so that Igf-2 is transcribed only from the paternal chromosome and H19 (including miR-675) only from the maternal chromosome. In this review, we will discuss the relevance of (i) proper somatic imprinting, (ii) erasure of imprinting and (iii) loss of imprinting within the DMRs at the Igf-2-H19 locus to the expression of genes involved in IFS, and the consequences of these alternative patterns of imprinting for stem cell biology.

  4. Bovine DNA methylation imprints are established in an oocyte size-specific manner, which are coordinated with the expression of the DNMT3 family proteins.

    PubMed

    O'Doherty, Alan M; O'Shea, Lynne C; Fair, Trudee

    2012-03-01

    A subset of genes, known as imprinted genes, is present in the mammalian genome. Genomic imprinting governs the monoallelic expression of these genes, depending on whether the gene was inherited from the sperm or the egg. This parent-of-origin specific gene expression is generally dependent on the epigenetic modification, DNA methylation, and the DNA methylation status of CpG dinucleotides residing in loci known as differentially methylated regions (DMRs). The enzymatic machinery responsible for the addition of methyl (-CH(3)) groups to the cytosine residue in the CpG dinucleotides are known as DNA methyltransferases (DNMTs). Correct establishment and maintenance of methylation patterns at imprinted genes has been associated with placental function and regulation of embryonic/fetal development. Much work has been carried out on imprinted genes in mouse and human; however, little is known about the methylation dynamics in the bovine oocyte. The primary objective of the present study was to characterize the establishment of methylation at maternally imprinted genes in bovine growing oocytes and to determine if the expression of the bovine DNMTs-DNMT3A, DNMT3B, and DNMT3L-was coordinated with DNA methylation during oocyte development. To this end, a panel of maternally imprinted genes was selected (SNRPN, MEST, IGF2R, PEG10, and PLAGL1) and putative DMRs for MEST, IGF2R, PEG10, and PLAGL1 were identified within the 5' regions for each gene; the SNRPN DMR has been reported previously. Conventional bisulfite sequencing revealed that methylation marks were acquired at all five DMRs investigated in an oocyte size-dependent fashion. This was confirmed for a selection of genes using pyrosequencing analysis. Furthermore, mRNA expression and protein analysis revealed that DNMT3A, DNMT3B, and DNMT3L are also present in the bovine oocyte during its growth phase. This study demonstrates for the first time that an increase in bovine imprinted gene DMR methylation occurs during

  5. Two Isoforms of the RNA Binding Protein, Coding Region Determinant-binding Protein (CRD-BP/IGF2BP1), Are Expressed in Breast Epithelium and Support Clonogenic Growth of Breast Tumor Cells.

    PubMed

    Fakhraldeen, Saja A; Clark, Rod J; Roopra, Avtar; Chin, Emily N; Huang, Wei; Castorino, John; Wisinski, Kari B; Kim, TaeWon; Spiegelman, Vladimir S; Alexander, Caroline M

    2015-05-22

    CRD-BP/IGF2BP1 has been characterized as an "oncofetal" RNA binding protein typically highly expressed in embryonic tissues, suppressed in normal adult tissues, but induced in many tumor types. In this study, we show that adult breast tissues express ubiquitous but low levels of CRD-BP protein and mRNA. Although CRD-BP mRNA expression is induced in breast tumor cells, levels remain ∼1000-fold lower than in embryonic tissues. Despite low expression levels, CRD-BP is required for clonogenic growth of breast cancer cells. We reveal that because the most common protein isoform in normal adult breast and breast tumors has an N-terminal deletion (lacking two RNA recognition motif (RRM) domains) and is therefore missing antibody epitopes, CRD-BP expression has been under-reported by previous studies. We show that a CRD-BP mutant mouse strain retains expression of the shorter transcript (ΔN-CRD-BP), which originates in intron 2, suggesting that the impact of complete ablation of this gene in mice is not yet known. Either the full-length CRD-BP or the N-terminally truncated version can rescue the clonogenicity of CRD-BP knockdown breast cancer cells, suggesting that clonogenic function is served by either CRD-BP isoform. In summary, although CRD-BP expression levels are low in breast cancer cells, this protein is necessary for clonogenic activity.

  6. IGF-2 is necessary for Retinoblastoma-mediated enhanced adaptation after small bowel resection

    PubMed Central

    Choi, Pamela M.; Sun, Raphael C.; Sommovilla, Josh; Diaz-Miron, Jose; Guo, Jun; Erwin, Christopher R.; Warner, Brad W.

    2014-01-01

    Background Previously, we have demonstrated that genetically disrupting retinoblastoma protein (Rb) expression in enterocytes results in taller villi, mimicking resection-induced adaption responses. Rb deficiency also results in elevated IGF-2 expression in villus enterocytes. We propose that postoperative disruption of Rb results in enhanced adaptation which is driven by IGF-2. Methods Inducible, intestine-specific Rb-null mice (iRbIKO) and wild-type littermates (WT) underwent a 50% proximal small bowel resection (SBR) at 7–9 weeks of age. They were then were given tamoxifen on POD 4–6, and harvested on POD 28. The experiment was then repeated on double knockouts of both IGF-2 and Rb (IGF-2 null/iRbIKO). Results iRbIKO mice demonstrated enhanced resection-induced adaptive villus growth after SBR and increased IGF-2 mRNA in ileal villus enterocytes compared to their WT littermates. In the IGF-2 null/iRbIKO double knockout mice, there was no additional villus growth beyond what was expected of normal resection-induced adaptation. Conclusions Adult mice in which Rb is inducibly deleted from the intestinal epithelium following SBR have augmented adaptive growth. IGF-2 expression is necessary for enhanced adaptation associated with acute intestinal Rb deficiency. PMID:25002022

  7. Modulation of imprinted gene network in placenta results in normal development of in vitro manipulated mouse embryos.

    PubMed

    Fauque, Patricia; Ripoche, Marie-Anne; Tost, Jörg; Journot, Laurent; Gabory, Anne; Busato, Florence; Le Digarcher, Anne; Mondon, Françoise; Gut, Ivo; Jouannet, Pierre; Vaiman, Daniel; Dandolo, Luisa; Jammes, Hélène

    2010-05-01

    Genomic imprinting regulates the expression of a group of genes monoallelically expressed in a parent-of-origin specific manner. Allele-specific DNA methylation occurs at differentially methylated regions (DMRs) of these genes. We have previously shown that in vitro fertilization and embryo culture result in methylation defects at the imprinted H19-Igf2 locus at the blastocyst stage. The current study was designed to evaluate the consequences of these manipulations on genomic imprinting after implantation in the mouse. Blastocysts were produced following three experimental conditions: (i) embryos maintained in culture medium after in vivo fertilization or (ii) in vitro fertilization and (iii) a control group with embryos obtained after in vivo fertilization and timed mating. Blastocysts were all transplanted into pseudopregnant females. Embryos and placentas were collected on day 10.5 of development. DNA methylation patterns of the H19, Igf2, Igf2r and Dlk1-Dio3 DMRs were analyzed by quantitative pyrosequencing. In contrast to blastocyst stage, methylation profiles were normal both in embryonic and placental tissues after in vitro fertilization and culture. Expression of a selected set of imprinting genes from the recently described imprinted gene network (IGN) (including Igf2 and H19) was analyzed in placental tissues by quantitative RT-PCR. Placentas obtained after in vitro fertilization and embryo culture displayed significantly disturbed levels of H19 and Igf2 mRNA, as well as of most other genes from the IGN. As embryos were phenotypically normal, we hypothesize that the modulation of a coordinated network of imprinted genes results in a compensatory process capable of correcting potential dysfunction of placenta.

  8. IGF-2R-Gαq signaling and cardiac hypertrophy in the low-birth-weight lamb.

    PubMed

    Wang, Kimberley C W; Tosh, Darran N; Zhang, Song; McMillen, I Caroline; Duffield, Jaime A; Brooks, Doug A; Morrison, Janna L

    2015-04-01

    The cardiac insulin-like growth factor 2 receptor (IGF-2R) can induce cardiomyocyte hypertrophy in a heterotrimeric G protein receptor-coupled manner involving αq (Gαq) or αs (Gαs). We have previously shown increased left ventricular weight and cardiac IGF-2 and IGF-2R gene expression in low-birth-weight (LBW) compared with average-birth-weight (ABW) lambs. Here, we have investigated the cardiac expression of IGF-2 gene variants, the degree of histone acetylation, and the abundance of proteins in the IGF-2R downstream signaling pathway in ABW and LBW lambs. Samples from the left ventricle of ABW and LBW lambs were collected at 21 days of age. There was increased phospho-CaMKII protein with decreased HDAC 4 abundance in the LBW compared with ABW lambs. There was increased GATA 4 and decreased phospho-troponin I abundance in LBW compared with ABW lambs, which are markers of pathological cardiac hypertrophy and impaired or reduced contractility, respectively. There was increased histone acetylation of H3K9 at IGF-2R promoter and IGF-2R intron 2 differentially methylated region in the LBW lamb. In conclusion, histone acetylation of IGF-2R may lead to increased IGF-2R mRNA expression and subsequently mediate Gαq signaling early in life via CaMKII, resulting in an increased risk of left ventricular hypertrophy and cardiovascular disease in adult life.

  9. IGF-2R-Gαq signaling and cardiac hypertrophy in the low-birth-weight lamb

    PubMed Central

    Wang, Kimberley C. W.; Tosh, Darran N.; Zhang, Song; McMillen, I. Caroline; Duffield, Jaime A.; Brooks, Doug A.

    2015-01-01

    The cardiac insulin-like growth factor 2 receptor (IGF-2R) can induce cardiomyocyte hypertrophy in a heterotrimeric G protein receptor-coupled manner involving αq (Gαq) or αs (Gαs). We have previously shown increased left ventricular weight and cardiac IGF-2 and IGF-2R gene expression in low-birth-weight (LBW) compared with average-birth-weight (ABW) lambs. Here, we have investigated the cardiac expression of IGF-2 gene variants, the degree of histone acetylation, and the abundance of proteins in the IGF-2R downstream signaling pathway in ABW and LBW lambs. Samples from the left ventricle of ABW and LBW lambs were collected at 21 days of age. There was increased phospho-CaMKII protein with decreased HDAC 4 abundance in the LBW compared with ABW lambs. There was increased GATA 4 and decreased phospho-troponin I abundance in LBW compared with ABW lambs, which are markers of pathological cardiac hypertrophy and impaired or reduced contractility, respectively. There was increased histone acetylation of H3K9 at IGF-2R promoter and IGF-2R intron 2 differentially methylated region in the LBW lamb. In conclusion, histone acetylation of IGF-2R may lead to increased IGF-2R mRNA expression and subsequently mediate Gαq signaling early in life via CaMKII, resulting in an increased risk of left ventricular hypertrophy and cardiovascular disease in adult life. PMID:25632020

  10. Germline and somatic imprinting in the nonhuman primate highlights species differences in oocyte methylation.

    PubMed

    Cheong, Clara Y; Chng, Keefe; Ng, Shilen; Chew, Siew Boom; Chan, Louiza; Ferguson-Smith, Anne C

    2015-05-01

    Genomic imprinting is an epigenetic mechanism resulting in parental allele-specific gene expression. Defects in normal imprinting are found in cancer, assisted reproductive technologies, and several human syndromes. In mouse models, germline-derived DNA methylation is shown to regulate imprinting. Though imprinting is largely conserved between mammals, species- and tissue-specific domains of imprinted expression exist. Using the cynomolgus macaque (Macaca fascicularis) to assess primate-specific imprinting, we present a comprehensive view of tissue-specific imprinted expression and DNA methylation at established imprinted gene clusters. For example, like mouse and unlike human, macaque IGF2R is consistently imprinted, and the PLAGL1, INPP5F transcript variant 2, and PEG3 imprinting control regions are not methylated in the macaque germline but acquire this post-fertilization. Methylome data from human early embryos appear to support this finding. These suggest fundamental differences in imprinting control mechanisms between primate species and rodents at some imprinted domains, with implications for our understanding of the epigenetic programming process in humans and its influence on disease.

  11. RNA-binding protein IGF2BP3 targeting of oncogenic transcripts promotes hematopoietic progenitor proliferation

    PubMed Central

    Palanichamy, Jayanth Kumar; Tran, Tiffany M.; Howard, Jonathan M.; Contreras, Jorge R.; Fernando, Thilini R.; Sterne-Weiler, Timothy; Katzman, Sol; Toloue, Masoud; Yan, Weihong; Sanford, Jeremy R.; Rao, Dinesh S.

    2016-01-01

    Posttranscriptional control of gene expression is important for defining both normal and pathological cellular phenotypes. In vitro, RNA-binding proteins (RBPs) have recently been shown to play important roles in posttranscriptional regulation; however, the contribution of RBPs to cell specification is not well understood. Here, we determined that the RBP insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3) is specifically overexpressed in mixed lineage leukemia–rearranged (MLL-rearranged) B-acute lymphoblastic leukemia (B-ALL), which constitutes a subtype of this malignancy associated with poor prognosis and high risk of relapse. IGF2BP3 was required for the survival of B-ALL cell lines, as knockdown led to decreased proliferation and increased apoptosis. Enforced expression of IGF2BP3 provided murine BM cells with a strong survival advantage, led to proliferation of hematopoietic stem and progenitor cells, and skewed hematopoietic development to the B cell/myeloid lineage. Cross-link immunoprecipitation and high throughput sequencing uncovered the IGF2BP3-regulated transcriptome, which includes oncogenes MYC and CDK6 as direct targets. IGF2BP3 regulated transcripts via targeting elements within 3′ untranslated regions (3′UTR), and enforced IGF2BP3 expression in mice resulted in enhanced expression of Myc and Cdk6 in BM. Together, our data suggest that IGF2BP3-mediated targeting of oncogenic transcripts may represent a critical pathogenetic mechanism in MLL-rearranged B-ALL and support IGF2BP3 and its cognate RNA-binding partners as potential therapeutic targets in this disease. PMID:26974154

  12. RNA-binding protein IGF2BP3 targeting of oncogenic transcripts promotes hematopoietic progenitor proliferation.

    PubMed

    Palanichamy, Jayanth Kumar; Tran, Tiffany M; Howard, Jonathan M; Contreras, Jorge R; Fernando, Thilini R; Sterne-Weiler, Timothy; Katzman, Sol; Toloue, Masoud; Yan, Weihong; Basso, Giuseppe; Pigazzi, Martina; Sanford, Jeremy R; Rao, Dinesh S

    2016-04-01

    Posttranscriptional control of gene expression is important for defining both normal and pathological cellular phenotypes. In vitro, RNA-binding proteins (RBPs) have recently been shown to play important roles in posttranscriptional regulation; however, the contribution of RBPs to cell specification is not well understood. Here, we determined that the RBP insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3) is specifically overexpressed in mixed lineage leukemia-rearranged (MLL-rearranged) B-acute lymphoblastic leukemia (B-ALL), which constitutes a subtype of this malignancy associated with poor prognosis and high risk of relapse. IGF2BP3 was required for the survival of B-ALL cell lines, as knockdown led to decreased proliferation and increased apoptosis. Enforced expression of IGF2BP3 provided murine BM cells with a strong survival advantage, led to proliferation of hematopoietic stem and progenitor cells, and skewed hematopoietic development to the B cell/myeloid lineage. Cross-link immunoprecipitation and high throughput sequencing uncovered the IGF2BP3-regulated transcriptome, which includes oncogenes MYC and CDK6 as direct targets. IGF2BP3 regulated transcripts via targeting elements within 3' untranslated regions (3'UTR), and enforced IGF2BP3 expression in mice resulted in enhanced expression of Myc and Cdk6 in BM. Together, our data suggest that IGF2BP3-mediated targeting of oncogenic transcripts may represent a critical pathogenetic mechanism in MLL-rearranged B-ALL and support IGF2BP3 and its cognate RNA-binding partners as potential therapeutic targets in this disease.

  13. Insulin-like Growth Factor 2 (IGF-2) Potentiates BMP-9-Induced Osteogenic Differentiation and Bone Formation

    PubMed Central

    Chen, Liang; Jiang, Wei; Huang, Jiayi; He, Bai-Cheng; Zuo, Guo-Wei; Zhang, Wenli; Luo, Qing; Shi, Qiong; Zhang, Bing-Qiang; Wagner, Eric R; Luo, Jinyong; Tang, Min; Wietholt, Christian; Luo, Xiaoji; Bi, Yang; Su, Yuxi; Liu, Bo; Kim, Stephanie H; He, Connie J; Hu, Yawen; Shen, Jikun; Rastegar, Farbod; Huang, Enyi; Gao, Yanhong; Gao, Jian-Li; Zhou, Jian-Zhong; Reid, Russell R; Luu, Hue H; Haydon, Rex C; He, Tong-Chuan; Deng, Zhong-Liang

    2010-01-01

    Efficient osteogenic differentiation and bone formation from mesenchymal stem cells (MSCs) should have clinical applications in treating nonunion fracture healing. MSCs are adherent bone marrow stromal cells that can self-renew and differentiate into osteogenic, chondrogenic, adipogenic, and myogenic lineages. We have identified bone morphogenetic protein 9 (BMP-9) as one of the most osteogenic BMPs. Here we investigate the effect of insulin-like growth factor 2 (IGF-2) on BMP-9-induced bone formation. We have found that endogenous IGF-2 expression is low in MSCs. Expression of IGF-2 can potentiate BMP-9-induced early osteogenic marker alkaline phosphatase (ALP) activity and the expression of later markers. IGF-2 has been shown to augment BMP-9-induced ectopic bone formation in the stem cell implantation assay. In perinatal limb explant culture assay, IGF-2 enhances BMP-9-induced endochondral ossification, whereas IGF-2 itself can promote the expansion of the hypertropic chondrocyte zone of the cultured limb explants. Expression of the IGF antagonists IGFBP3 and IGFBP4 leads to inhibition of the IGF-2 effect on BMP-9-induced ALP activity and matrix mineralization. Mechanistically, IGF-2 is further shown to enhance the BMP-9-induced BMPR-Smad reporter activity and Smad1/5/8 nuclear translocation. PI3-kinase (PI3K) inhibitor LY294002 abolishes the IGF-2 potentiation effect on BMP-9-mediated osteogenic signaling and can directly inhibit BMP-9 activity. These results demonstrate that BMP-9 crosstalks with IGF-2 through PI3K/AKT signaling pathway during osteogenic differentiation of MSCs. Taken together, our findings suggest that a combination of BMP-9 and IGF-2 may be explored as an effective bone-regeneration agent to treat large segmental bony defects, nonunion fracture, and/or osteoporotic fracture. © 2010 American Society for Bone and Mineral Research. PMID:20499340

  14. Disrupted imprinting status at the H19 differentially methylated region is associated with the resorbed embryo phenotype in rats.

    PubMed

    Pathak, Shilpa; Saxena, Madhurima; D'Souza, Ryan; Balasinor, N H

    2010-01-01

    Igf2, an imprinted gene that is paternally expressed in embryos, encodes an embryonic growth factor. An important regulator of Igf2 expression is methylation of the H19 differentially methylated region (DMR). A significant association has been observed between sperm methylation status at the H19 DMR and post-implantation loss. In addition, tamoxifen treatment has been shown to increase post-implantation loss and reduce DNA methylation at the H19 DMR in rat spermatozoa. Because this DMR is a primary DMR transmitting epigenetic imprint information from the gametes to the embryo, the aim of the present study was to determine the imprinting status of H19 DMR in post-implantation normal and resorbed embryos (F(1)) and to compare it with the H19 DMR in the spermatozoa of the respective sires. Analysis of the H19 DMR revealed methylation errors in resorbed embryo that were also observed in their sires' spermatozoa in the control and tamoxifen-treated groups. Expression analysis of the reciprocally imprinted genes Igf2 and H19 showed significant downregulation of Igf2 protein without any effect on H19 transcript levels in the resorbed embryos. The results indicate an association between disrupted imprinting status at the H19 DMR in resorbed embryos and the spermatozoa from their respective sires regardless of treatment, implying a common mechanism of resorption. The results demonstrate transmission of methylation errors at the Igf2-H19 locus through the paternal germline to the subsequent generation, emphasising the role of paternal factors during embryogenesis.

  15. Perinatal high methyl donor alters gene expression in IGF system in male offspring without altering DNA methylation

    PubMed Central

    Amarger, Valérie; Giudicelli, Fanny; Pagniez, Anthony; Parnet, Patricia

    2017-01-01

    Aim: To investigate the effect of a protein restriction and a supplementation with methyl donor nutrients during fetal and early postnatal life on the expression and epigenetic state of imprinted genes from the IGF system. Materials & methods: Pregnant female rats were fed a protein-restricted diet supplemented or not with methyl donor. Results: Gene expression of the Igf2, H19, Igf1, Igf2r and Plagl1 genes in the liver of male offspring at birth and weaning was strongly influenced by maternal diet. Whereas the methylation profiles of the Igf2, H19 and Igf2r genes were remarkably stable, DNA methylation of Plagl1 promoter was slightly modified. Conclusion: DNA methylation of most, but not all, imprinted gene regulatory regions was resistant to methyl group nutritional supply. PMID:28344827

  16. Expression profile and transcription factor binding site exploration of imprinted genes in human and mouse

    PubMed Central

    Steinhoff, Christine; Paulsen, Martina; Kielbasa, Szymon; Walter, Jörn; Vingron, Martin

    2009-01-01

    Background In mammals, imprinted genes are regulated by an epigenetic mechanism that results in parental origin-specific expression. Though allele-specific regulation of imprinted genes has been studied for several individual genes in detail, little is known about their overall tissue-specific expression patterns and interspecies conservation of expression. Results We performed a computational analysis of microarray expression data of imprinted genes in human and mouse placentae and in a variety of adult tissues. For mouse, early embryonic stages were also included. The analysis reveals that imprinted genes are expressed in a broad spectrum of tissues for both species. Overall, the relative tissue-specific expression levels of orthologous imprinted genes in human and mouse are not highly correlated. However, in both species distinctive expression profiles are found in tissues of the endocrine pathways such as adrenal gland, pituitary, pancreas as well as placenta. In mouse, the placental and embryonic expression patterns of imprinted genes are highly similar. Transcription factor binding site (TFBS) prediction reveals correlation of tissue-specific expression patterns and the presence of distinct TFBS signatures in the upstream region of human imprinted genes. Conclusion Imprinted genes are broadly expressed pre- and postnatally and do not exhibit a distinct overall expression pattern when compared to non-imprinted genes. The relative expression of most orthologous gene pairs varies significantly between human and mouse suggesting rapid species-specific changes in gene regulation. Distinct expression profiles of imprinted genes are confined to certain human and mouse hormone producing tissues, and placentae. In contrast to the overall variability, distinct expression profiles and enriched TFBS signatures are found in human and mouse endocrine tissues and placentae. This points towards an important role played by imprinted gene regulation in these tissues. PMID

  17. IGF2R Genetic Variants, Circulating IGF2 Concentrations and Colon Cancer Risk in African Americans and Whites

    PubMed Central

    Hoyo, Cathrine; Murphy, Susan K.; Schildkraut, Joellen M.; Vidal, Adriana C.; Skaar, David; Millikan, Robert C.; Galanko, Joseph; Sandler, Robert S.; Jirtle, Randy; Keku, Temitope

    2012-01-01

    The Mannose 6 Phosphate/Insulin-like Growth Factor Receptor-2 (IGF2R) encodes a type-1 membrane protein that modulates availability of the potent mitogen, IGF2. We evaluated the associations between IGF2R non-synonymous genetic variants (c.5002G>A, Gly1619Arg(rs629849), and c.901C>G, Leu252Val(rs8191754)), circulating IGF2 levels, and colon cancer (CC) risk among African American and White participants enrolled in the North Carolina Colon Cancer Study (NCCCS). Generalized linear models were used to compare circulating levels of IGF2 among 298 African American and 518 White controls. Logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the association of IGF2R genetic variants and CC risk. Women homozygous for the IGF2R c.5002 G>A allele, had higher mean levels of circulating IGF2, 828 (SD=321) ng/ml compared to non-carriers, 595 (SD=217) ng/ml (p-value=0.01). This pattern was not apparent in individuals homozygous for the IGF2R c.901 C>G variant. Whites homozygous for the IGF2R c.901 C>G variant trended towards a higher risk of CC, OR=2.2 [95% CI(0.9–5.4)], whereas carrying the IGF2R c.5002 G>A variant was not associated with CC risk. Our findings support the hypothesis that being homozygous for the IGF2R c.5002 G>A modulates IGF2 circulating levels in a sex-specific manner, and while carrying the IGF2R c.901 C>G may increase cancer risk, the mechanism may not involve modulation of circulating IGF2. PMID:22377707

  18. The role and interaction of imprinted genes in human fetal growth.

    PubMed

    Moore, Gudrun E; Ishida, Miho; Demetriou, Charalambos; Al-Olabi, Lara; Leon, Lydia J; Thomas, Anna C; Abu-Amero, Sayeda; Frost, Jennifer M; Stafford, Jaime L; Chaoqun, Yao; Duncan, Andrew J; Baigel, Rachel; Brimioulle, Marina; Iglesias-Platas, Isabel; Apostolidou, Sophia; Aggarwal, Reena; Whittaker, John C; Syngelaki, Argyro; Nicolaides, Kypros H; Regan, Lesley; Monk, David; Stanier, Philip

    2015-03-05

    Identifying the genetic input for fetal growth will help to understand common, serious complications of pregnancy such as fetal growth restriction. Genomic imprinting is an epigenetic process that silences one parental allele, resulting in monoallelic expression. Imprinted genes are important in mammalian fetal growth and development. Evidence has emerged showing that genes that are paternally expressed promote fetal growth, whereas maternally expressed genes suppress growth. We have assessed whether the expression levels of key imprinted genes correlate with fetal growth parameters during pregnancy, either early in gestation, using chorionic villus samples (CVS), or in term placenta. We have found that the expression of paternally expressing insulin-like growth factor 2 (IGF2), its receptor IGF2R, and the IGF2/IGF1R ratio in CVS tissues significantly correlate with crown-rump length and birthweight, whereas term placenta expression shows no correlation. For the maternally expressing pleckstrin homology-like domain family A, member 2 (PHLDA2), there is no correlation early in pregnancy in CVS but a highly significant negative relationship in term placenta. Analysis of the control of imprinted expression of PHLDA2 gave rise to a maternally and compounded grand-maternally controlled genetic effect with a birthweight increase of 93/155 g, respectively, when one copy of the PHLDA2 promoter variant is inherited. Expression of the growth factor receptor-bound protein 10 (GRB10) in term placenta is significantly negatively correlated with head circumference. Analysis of the paternally expressing delta-like 1 homologue (DLK1) shows that the paternal transmission of type 1 diabetes protective G allele of rs941576 single nucleotide polymorphism (SNP) results in significantly reduced birth weight (-132 g). In conclusion, we have found that the expression of key imprinted genes show a strong correlation with fetal growth and that for both genetic and genomics data analyses, it

  19. Allelic expression of mammalian imprinted genes in a matrotrophic lizard, Pseudemoia entrecasteauxii.

    PubMed

    Griffith, Oliver W; Brandley, Matthew C; Belov, Katherine; Thompson, Michael B

    2016-03-01

    Genomic imprinting is a process that results in the differential expression of genes depending on their parent of origin. It occurs in both plants and live-bearing mammals, with imprinted genes typically regulating the ability of an embryo to manipulate the maternal provision of nutrients. Genomic imprinting increases the potential for selection to act separately on paternally and maternally expressed genes, which increases the number of opportunities that selection can facilitate embryonic control over maternal nutrient provision. By looking for imprinting in an independent matrotrophic lineage, the viviparous lizard Pseudemoia entrecasteauxii (Scincidae), we test the hypothesis that genomic imprinting facilitates the evolution of substantial placental nutrient transport to embryos (matrotrophy). We sequenced transcriptomes from the embryonic component of lizard placentae to determine whether there are parent-of-origin differences in expression of genes that are imprinted in mammals. Of these genes, 19 had sufficiently high expression in the lizard to identify polymorphisms in transcribed sequences. We identified bi-allelic expression in 17 genes (including insulin-like growth factor 2), indicating that neither allele was imprinted. These data suggest that either genomic imprinting has not evolved in this matrotrophic skink or, if it has, it has evolved in different genes to mammals. We outline how these hypotheses can be tested. This study highlights important differences between mammalian and reptile pregnancy and the absence of any shared imprinting genes reflects fundamental differences in the way that pregnancy has evolved in these two lineages.

  20. Global assessment of imprinted gene expression in the bovine conceptus by next generation sequencing.

    PubMed

    Chen, Zhiyuan; Hagen, Darren E; Wang, Juanbin; Elsik, Christine G; Ji, Tieming; Siqueira, Luiz G; Hansen, Peter J; Rivera, Rocío M

    2016-07-02

    Genomic imprinting is an epigenetic mechanism that leads to parental-allele-specific gene expression. Approximately 150 imprinted genes have been identified in humans and mice but less than 30 have been described as imprinted in cattle. For the purpose of de novo identification of imprinted genes in bovine, we determined global monoallelic gene expression in brain, skeletal muscle, liver, kidney and placenta of day ∼105 Bos taurus indicus × Bos taurus taurus F1 conceptuses using RNA sequencing. To accomplish this, we developed a bioinformatics pipeline to identify parent-specific single nucleotide polymorphism alleles after filtering adenosine to inosine (A-to-I) RNA editing sites. We identified 53 genes subject to monoallelic expression. Twenty three are genes known to be imprinted in the cow and an additional 7 have previously been characterized as imprinted in human and/or mouse that have not been reported as imprinted in cattle. Of the remaining 23 genes, we found that 10 are uncharacterized or unannotated transcripts located in known imprinted clusters, whereas the other 13 genes are distributed throughout the bovine genome and are not close to any known imprinted clusters. To exclude potential cis-eQTL effects on allele expression, we corroborated the parental specificity of monoallelic expression in day 86 Bos taurus taurus × Bos taurus taurus conceptuses and identified 8 novel bovine imprinted genes. Further, we identified 671 candidate A-to-I RNA editing sites and describe random X-inactivation in day 15 bovine extraembryonic membranes. Our results expand the imprinted gene list in bovine and demonstrate that monoallelic gene expression can be the result of cis-eQTL effects.

  1. Global assessment of imprinted gene expression in the bovine conceptus by next generation sequencing

    PubMed Central

    Chen, Zhiyuan; Hagen, Darren E.; Wang, Juanbin; Elsik, Christine G.; Ji, Tieming; Siqueira, Luiz G.; Hansen, Peter J.; Rivera, Rocío M.

    2016-01-01

    ABSTRACT Genomic imprinting is an epigenetic mechanism that leads to parental-allele-specific gene expression. Approximately 150 imprinted genes have been identified in humans and mice but less than 30 have been described as imprinted in cattle. For the purpose of de novo identification of imprinted genes in bovine, we determined global monoallelic gene expression in brain, skeletal muscle, liver, kidney and placenta of day ∼105 Bos taurus indicus × Bos taurus taurus F1 conceptuses using RNA sequencing. To accomplish this, we developed a bioinformatics pipeline to identify parent-specific single nucleotide polymorphism alleles after filtering adenosine to inosine (A-to-I) RNA editing sites. We identified 53 genes subject to monoallelic expression. Twenty three are genes known to be imprinted in the cow and an additional 7 have previously been characterized as imprinted in human and/or mouse that have not been reported as imprinted in cattle. Of the remaining 23 genes, we found that 10 are uncharacterized or unannotated transcripts located in known imprinted clusters, whereas the other 13 genes are distributed throughout the bovine genome and are not close to any known imprinted clusters. To exclude potential cis-eQTL effects on allele expression, we corroborated the parental specificity of monoallelic expression in day 86 Bos taurus taurus × Bos taurus taurus conceptuses and identified 8 novel bovine imprinted genes. Further, we identified 671 candidate A-to-I RNA editing sites and describe random X-inactivation in day 15 bovine extraembryonic membranes. Our results expand the imprinted gene list in bovine and demonstrate that monoallelic gene expression can be the result of cis-eQTL effects. PMID:27245094

  2. STAT3-mediated IGF-2 secretion in the tumour microenvironment elicits innate resistance to anti-IGF-1R antibody

    PubMed Central

    Lee, Ji-Sun; Kang, Ju-Hee; Boo, Hye-Jin; Hwang, Su-Jung; Hong, Sungyoul; Lee, Su-Chan; Park, Young-Jun; Chung, Tae-Moon; Youn, Hyewon; Mi Lee, Seung; Jae Kim, Byoung; Chung, June-Key; Chung, Yeonseok; William, William N.; Kee Shin, Young; Lee, Hyo-Jong; Oh, Seung-Hyun; Lee, Ho-Young

    2015-01-01

    Drug resistance is a major impediment in medical oncology. Recent studies have emphasized the importance of the tumour microenvironment (TME) to innate resistance, to molecularly targeted therapies. In this study, we investigate the role of TME in resistance to cixutumumab, an anti-IGF-1R monoclonal antibody that has shown limited clinical efficacy. We show that treatment with cixutumumab accelerates tumour infiltration of stromal cells and metastatic tumour growth, and decreases overall survival of mice. Cixutumumab treatment stimulates STAT3-dependent transcriptional upregulation of IGF-2 in cancer cells and recruitment of macrophages and fibroblasts via paracrine IGF-2/IGF-2R activation, resulting in the stroma-derived CXCL8 production, and thus angiogenic and metastatic environment. Silencing IGF-2 or STAT3 expression in cancer cells or IGF-2R or CXCL8 expression in stromal cells significantly inhibits the cancer–stroma communication and vascular endothelial cells' angiogenic activities. These findings suggest that blocking the STAT3/IGF-2/IGF-2R intercellular signalling loop may overcome the adverse consequences of anti-IGF-1R monoclonal antibody-based therapies. PMID:26465273

  3. Expression profiling of uniparental mouse embryos is inefficient in identifying novel imprinted genes.

    PubMed

    Ruf, Nico; Dünzinger, Ulrich; Brinckmann, Anja; Haaf, Thomas; Nürnberg, Peter; Zechner, Ulrich

    2006-04-01

    Imprinted genes are expressed from only one allele in a parent-of-origin-specific manner. We here describe a systematic approach to identify novel imprinted genes using quantification of allele-specific expression by Pyrosequencing, a highly accurate method to detect allele-specific expression differences. Sixty-eight candidate imprinted transcripts mapping to known imprinted chromosomal regions were selected from a recent expression profiling study of uniparental mouse embryos and analyzed. Three novel imprinted transcripts encoding putative non-protein-coding RNAs were identified on the basis of parent-of-origin-specific monoallelic expression in E11.5 (C57BL/6 x Cast/Ei)F1 and informative (C57BL/6 x Cast/Ei) x C57BL/6 backcross embryos. In addition, four transcripts with preferential expression of a strain-specific allele were found. Intriguingly, a vast majority of the analyzed transcripts showed no imprinting-associated expression in F1 embryos. These data strengthen the view that a large fraction of nonimprinted genes is differentially expressed between parthenogenetic and androgenetic embryos and question the efficiency of expression profiling of uniparental embryos to identify novel imprinted genes.

  4. Methylation Status of H19/IGF2 Differentially Methylated Region in in vitro Human Blastocysts Donated by Healthy Couples

    PubMed Central

    Derakhshan-Horeh, Marzieh; Abolhassani, Farid; Jafarpour, Farnoosh; Moini, Ashraf; Karbalaie, Khadijeh; Hosseini, Sayyed Morteza; Ostadhosseini, Somayyeh; Nasr-Esfahani, Mohammad Hossein

    2017-01-01

    Background: Imprinted genes are a unique subset of few genes that have been differentially methylated region (DMR) in a parental origin-dependent manner during gametogenesis, and these genes are highly protected during pre-implantation epigenetic reprogramming. Several studies have shown that the particular vulnerability of imprinting genes during suboptimal pre- and peri-conception micro-environments often is occurred by assisted reproduction techniques (ART). This study investigated the methylation status of H19/IGF2 DMR at high-quality expanding/expanded human blastocysts donated by healthy individuals to evaluate the risks linked to ART. Method: Methylation levels of H19/IGF2 DMR were analyzed by bisulfite conversion and sequencing at 18 CpG sites (CpGs) located in this region. Result: The overall percentage of methylated CpGs and the proportion of hyper-methylated clones of H19/IGF2 DMR in analyzed blastocysts were 37.85±4.87% and 43.75±5.1%, respectively. For validation of our technique, the corresponding methylation levels of peripheral human lymphocytes were defined (49.52±1.86% and 50%, respectively). Conclusion: Considering the absence of in vivo- produced human embryos, it is not possible to conclude that the methylation found in H19/IGF2 DMR is actually normal or abnormal. Regarding the possible risks associated with ART, the procedures should be optimized in order to at least reduce some of the epigenetic risks. PMID:27432596

  5. Functional evolution of IGF2:IGF2R domain 11 binding generates novel structural interactions and a specific IGF2 antagonist

    PubMed Central

    Frago, Susana; Nicholls, Ryan D.; Strickland, Madeleine; Hughes, Jennifer; Williams, Christopher; Garner, Lee; Maclean, Rory; Rezgui, Dellel; Prince, Stuart N.; Zaccheo, Oliver J.; Ebner, Daniel; Sanegre, Sabina; Yu, Sheng; Buffa, Francesca M.; Crump, Matthew P.; Hassan, Andrew Bassim

    2016-01-01

    Among the 15 extracellular domains of the mannose 6-phosphate/insulin-like growth factor-2 receptor (M6P/IGF2R), domain 11 has evolved a binding site for IGF2 to negatively regulate ligand bioavailability and mammalian growth. Despite the highly evolved structural loops of the IGF2:domain 11 binding site, affinity-enhancing AB loop mutations suggest that binding is modifiable. Here we examine the extent to which IGF2:domain 11 affinity, and its specificity over IGF1, can be enhanced, and we examine the structural basis of the mechanistic and functional consequences. Domain 11 binding loop mutants were selected by yeast surface display combined with high-resolution structure-based predictions, and validated by surface plasmon resonance. We discovered previously unidentified mutations in the ligand-interacting surface binding loops (AB, CD, FG, and HI). Five combined mutations increased rigidity of the AB loop, as confirmed by NMR. When added to three independently identified CD and FG loop mutations that reduced the koff value by twofold, these mutations resulted in an overall selective 100-fold improvement in affinity. The structural basis of the evolved affinity was improved shape complementarity established by interloop (AB-CD) and intraloop (FG-FG) side chain interactions. The high affinity of the combinatorial domain 11 Fc fusion proteins functioned as ligand-soluble antagonists or traps that depleted pathological IGF2 isoforms from serum and abrogated IGF2-dependent signaling in vivo. An evolved and reengineered high-specificity M6P/IGF2R domain 11 binding site for IGF2 may improve therapeutic targeting of the frequent IGF2 gain of function observed in human cancer. PMID:27140600

  6. Brain-expressed imprinted genes and adult behaviour: the example of Nesp and Grb10.

    PubMed

    Dent, Claire L; Isles, Anthony R

    2014-02-01

    Imprinted genes are defined by their parent-of-origin-specific monoallelic expression. Although the epigenetic mechanisms regulating imprinted gene expression have been widely studied, their functional importance is still unclear. Imprinted genes are associated with a number of physiologies, including placental function and foetal growth, energy homeostasis, and brain and behaviour. This review focuses on genomic imprinting in the brain and on two imprinted genes in particular, Nesp and paternal Grb10, which, when manipulated in animals, have been shown to influence adult behaviour. These two genes are of particular interest as they are expressed in discrete and overlapping neural regions, recognised as key "imprinting hot spots" in the brain. Furthermore, these two genes do not appear to influence placental function and/or maternal provisioning of offspring. Consequently, by understanding their behavioural function we may begin to shed light on the evolutionary significance of imprinted genes in the adult brain, independent of the recognised role in maternal care. In addition, we discuss the potential future directions of research investigating the function of these two genes and the behavioural role of imprinted genes more generally.

  7. Lack of imprinting of the human dopamine D4 receptor (DRD4) gene

    SciTech Connect

    Cichon, S.; Noethen, M.M.; Propping, P.; Wolf, H.K.

    1996-04-09

    The term genomic imprinting has been used to refer to the differential expression of genetic material depending on whether it has come from the male or female parent. In humans, the chromosomal region 11p15.5 has been shown to contain 2 imprinted genes (H19 and IGF2). The gene for the dopamine D4 receptor (DRD4), which is of great interest for research into neuropsychiatric disorders and psychopharmacology, is also located in this area. In the present study, we have examined the imprinting status of the DRD4 gene in brain tissue of an epileptic patient who was heterozygous for a 12 bp repeat polymorphism in exon 1 of the DRD4 gene. We show that both alleles are expressed in equivalent amounts. We therefore conclude that the DRD4 gene is not imprinted in the human brain. 30 refs., 1 fig.

  8. Association of chromosome arm 16q loss with loss of imprinting of insulin-like growth factor-II in Wilms tumor.

    PubMed

    Mummert, Stephanie K; Lobanenkov, Victor A; Feinberg, Andrew P

    2005-06-01

    The most common known molecular defect in Wilms tumor (WT) of the kidney, the most frequent solid tumor of childhood, is loss of imprinting (LOI) of the insulin-like growth factor-II gene (IGF2), which involves activation of the normally silent maternal allele of the gene and hypermethylation of a differentially methylated region upstream of the H19 gene. Hypermethylation impairs binding of the insulator protein CTCF, allowing activation of IGF2 by an enhancer shared between IGF2 and H19. Loss of heterozygosity (LOH) of 16q22.1 is found in 15% of WTs, and 16q22.1 harbors CTCF, raising the possibility that reduced CTCF could lead to LOI of IGF2 in some cases. We hypothesized that there is an association between LOH of 16q and LOI of IGF2 in WT. In 40 WTs examined, LOH of 16q was found in five, one of which also showed LOH of 11p15. All of the remaining four tumors showed LOI of IGF2, compared to 13 of 32 WTs without LOH of 16q or 11p (P = 0.040). When published data not previously analyzed in this manner were included, 6 of 6 tumors with 16q LOH (and without LOH of 11p) showed LOI of IGF2, compared to 24 of 52 without LOH (P = 0.015). Thus, a genetic (16q LOH) and an epigenetic (LOI of IGF2) alteration in WT are linked, the first such association described. Finally, haploinsufficiency of CTCF may be the basis of this association, given that CTCF expression in tumors with 16q LOH was 48% that of tumors without LOH.

  9. IGF2-derived miR-483 mediated oncofunction by suppressing DLC-1 and associated with colorectal cancer

    PubMed Central

    Liu, Yangyang; Yang, Zhe; Wu, Shaogen; Cao, Wangsen; Cui, Isabelle H.; Yu, Chenggong

    2016-01-01

    Emerging evidence indicates that IGF2 plays an important role in various human malignancies, including colorectal cancer (CRC). Hsa-miR-483 is located within intron 7 of the IGF2 locus. However, the mechanism by which increased IGF2 induces carcinogenesis remains largely elusive. DLC-1 has been identified as a candidate tumor suppressor. In this study, we aimed at investigating whether miR-483 transcription is IGF2-dependent, identifying the functional target of miR-483, and evaluating whether tissue and serum miR-483-3p or miR-483-5p levels are associated with CRC. Our results showed that sequences upstream miR-483 had undetectable promoter activity and levels of IGF2, miR-483-3p, and miR-483-5p were synchronously increased in CRC tissues. Positive correlations between IGF2 and miR-483-3p (r=0.4984, ***p<0.0001), and between IGF2 and miR-483-5p (r=0.6659, ***p<0.0001) expression were found. In addition, patients with CRC had a significantly higher serum miR-483-5p level (*p<0.05) compared to normal controls. DLC-1 expression was decreased in colorectal cancer tissues and diminished through transient transfection with miR-483-3p. Our results suggest that IGF2 may exert its oncofunction, at least partly, through its parasitic miR-483 which suppressed DLC-1 in CRC cells. Thus, miR-483 might serve as a new target for therapy and a potential biomarker for the detection of colorectal cancer. PMID:27366946

  10. Differential neuronal vulnerability identifies IGF-2 as a protective factor in ALS

    PubMed Central

    Allodi, Ilary; Comley, Laura; Nichterwitz, Susanne; Nizzardo, Monica; Simone, Chiara; Benitez, Julio Aguila; Cao, Ming; Corti, Stefania; Hedlund, Eva

    2016-01-01

    The fatal disease amyotrophic lateral sclerosis (ALS) is characterized by the loss of somatic motor neurons leading to muscle wasting and paralysis. However, motor neurons in the oculomotor nucleus, controlling eye movement, are for unknown reasons spared. We found that insulin-like growth factor 2 (IGF-2) was maintained in oculomotor neurons in ALS and thus could play a role in oculomotor resistance in this disease. We also showed that IGF-1 receptor (IGF-1R), which mediates survival pathways upon IGF binding, was highly expressed in oculomotor neurons and on extraocular muscle endplate. The addition of IGF-2 induced Akt phosphorylation, glycogen synthase kinase-3β phosphorylation and β-catenin levels while protecting ALS patient motor neurons. IGF-2 also rescued motor neurons derived from spinal muscular atrophy (SMA) patients from degeneration. Finally, AAV9::IGF-2 delivery to muscles of SOD1G93A ALS mice extended life-span by 10%, while preserving motor neurons and inducing motor axon regeneration. Thus, our studies demonstrate that oculomotor-specific expression can be utilized to identify candidates that protect vulnerable motor neurons from degeneration. PMID:27180807

  11. Expression of delta-like 1 homologue and insulin-like growth factor 2 through epigenetic regulation of the genes during development of mouse molar.

    PubMed

    Khan, Qalb-E-Saleem; Sehic, Amer; Skalleberg, Natalie; Landin, Maria A; Khuu, Cuong; Risnes, Steinar; Osmundsen, Harald

    2012-08-01

    Delta-like 1 homolog (Dlk1) and insulin-like growth factor 2 (Igf2) are two of six well-studied mouse imprinted gene clusters that are paternally expressed. Their expression is also linked to their maternally expressed non-coding RNAs, encoded by Gene trap locus 2 (Gtl2) and Imprinted maternally expressed transcript (H19), co-located as imprinted gene clusters. Using deoxyoligonucleotide microarrays and real-time RT-PCR analysis we showed Dlk1 and Gtl2 to exhibit a time-course of expression during tooth development that was similar to that of Igf2 and H19. Western blot analysis of proteins encoded by Dlk1 and Igf2 suggested that the levels of these proteins reflected those of the corresponding mRNAs. Immunohistochemical studies of DLK1 in murine molars detected the protein in both epithelial and mesenchymal regions, in developing cusp mesenchyme, and in newly synthesized enamel and dentin tubules. IGF2 protein was detected primarily at prenatal stages, suggesting that it may be active before birth. Analysis of methylation of cytosine-phosphate-guanine (CpG) islands in both Dlk1 and Igf2 suggested the presence of an increasing fraction of hypermethylated bases with increasing time of development. The increased levels of hypermethylation coincided both with the diminished levels of expression of Dlk1 and Igf2 and with decreased levels of DLK1 and IGF2 proteins in the tooth germ, suggesting that their expression is regulated via methylation of CpG islands present in these genes.

  12. Epigenetic and genetic alterations of the imprinting disorder Beckwith-Wiedemann syndrome and related disorders.

    PubMed

    Soejima, Hidenobu; Higashimoto, Ken

    2013-07-01

    Genomic imprinting is an epigenetic phenomenon that leads to parent-specific differential expression of a subset of genes. Most imprinted genes form clusters, or imprinting domains, and are regulated by imprinting control regions. As imprinted genes have an important role in growth and development, aberrant expression of imprinted genes due to genetic or epigenetic abnormalities is involved in the pathogenesis of human disorders, or imprinting disorders. Beckwith-Wiedemann syndrome (BWS) is a representative imprinting disorder characterized by macrosomia, macroglossia and abdominal wall defects, and exhibits a predisposition to tumorigenesis. The relevant imprinted chromosomal region in BWS is 11p15.5, which consists of two imprinting domains, IGF2/H19 and CDKN1C/KCNQ1OT1. BWS has five known causative epigenetic and genetic alterations: loss of methylation (LOM) at KvDMR1, gain of methylation (GOM) at H19DMR, paternal uniparental disomy, CDKN1C mutations and chromosomal rearrangements. Opposite methylation defects, GOM and LOM, at H19DMR are known to cause clinically opposite disorders: BWS and Silver-Russell syndrome, respectively. Interestingly, a recent study discovered that loss of function or gain of function of CDKN1C also causes clinically opposite disorders, BWS and IMAGe (intrauterine growth restriction, metaphyseal dysplasia, adrenal hypoplasia congenita, and genital anomalies) syndrome, respectively. Furthermore, several clinical studies have suggested a relationship between assisted reproductive technology (ART) and the risk of imprinting disorders, along with the existence of trans-acting factors that regulate multiple imprinted differentially methylated regions. In this review, we describe the latest knowledge surrounding the imprinting mechanism of 11p15.5, in addition to epigenetic and genetic etiologies of BWS, associated childhood tumors, the effects of ART and multilocus hypomethylation disorders.

  13. Analysis of genomic imprinting by quantitative allele-specific expression by Pyrosequencing(®).

    PubMed

    McKeown, Peter C; Fort, Antoine; Spillane, Charles

    2014-01-01

    Genomic imprinting is a parent-of-origin phenomenon whereby gene expression is restricted to the allele inherited from either the maternal or paternal parent. It has been described from flowering plants and eutherian mammals and may have evolved due to parental conflicts over resource allocation. In mammals, imprinted genes are responsible for ensuring correct rates of embryo development and for preventing parthenogenesis. The molecular basis of imprinting depends upon the presence of differential epigenetic marks on the alleles inherited from each parent, although in plants the exact mechanisms that control imprinting are still unclear in many cases. Recent studies have identified large numbers of candidate imprinted genes from Arabidopsis thaliana and other plants (see Chap. 7 by Köhler and colleagues elsewhere in this volume) providing the tools for more thorough investigation into how imprinted gene networks (IGNs) are regulated. Analysis of genomic imprinting in animals has revealed important information on how IGNs are regulated during development, which often involves intermediate levels of imprinting. In some instances, small but significant changes in the degree of parental bias in gene expression have been linked to developmental traits, livestock phenotypes, and human disease. As some of the imprinted genes recently reported from plants show differential rather than complete (binary) imprinting, there is a clear need for tools that can quantify the degree of allelic expression bias occurring at a transcribed locus. In this chapter, we describe the use of Quantification of Allele-Specific Expression by Pyrosequencing(®) (QUASEP) as a tool suitable for this challenge. We describe in detail the factors which ensure that a Pyrosequencing(®) assay will be suitable for giving robust QUASEP and the problems which may be encountered during the study of imprinted genes by Pyrosequencing(®), with particular reference to our work in A. thaliana and in cattle

  14. The nucleotides responsible for the direct physical contact between the chromatin insulator protein CTCF and the H19 imprinting control region manifest parent of origin-specific long-distance insulation and methylation-free domains

    PubMed Central

    Pant, Vinod; Mariano, Piero; Kanduri, Chandrasekhar; Mattsson, Anita; Lobanenkov, Victor; Heuchel, Rainer; Ohlsson, Rolf

    2003-01-01

    The repression of the maternally inherited Igf2 allele has been proposed to depend on a methylation-sensitive chromatin insulator organized by the 11 zinc finger protein CTCF at the H19 imprinting control region (ICR). Here we document that point mutations of the nucleotides in physical contact with CTCF within the endogenous H19 ICR lead to loss of CTCF binding and Igf2 imprinting only when passaged through the female germline. This effect is accompanied by a significant loss of methylation protection of the maternally derived H19 ICR. Because CTCF interacts with other imprinting control regions, it emerges as a central factor responsible for interpreting and propagating gamete-derived epigenetic marks and for organizing epigenetically controlled expression domains. PMID:12629040

  15. Gene expression profile in cerebrum in the filial imprinting of domestic chicks (Gallus gallus domesticus).

    PubMed

    Yamaguchi, Shinji; Fujii-Taira, Ikuko; Katagiri, Sachiko; Izawa, Ei-Ichi; Fujimoto, Yasuyuki; Takeuchi, Hideaki; Takano, Tatsuya; Matsushima, Toshiya; Homma, Koichi J

    2008-06-15

    In newly hatched chicks, gene expression in the brain has previously been shown to be up-regulated following filial imprinting. By applying cDNA microarrays containing 13,007 expressed sequence tags, we examined the comprehensive gene expression profiling of the intermediate medial mesopallium in the chick cerebrum, which has been shown to play a key role in filial imprinting. We found 52 up-regulated genes and 6 down-regulated genes of at least 2.0-fold changes 3h after the training of filial imprinting, compared to the gene expression of the dark-reared chick brain. The up-regulated genes are known to be involved in a variety of pathways, including signal transduction, cytoskeletal organization, nuclear function, cell metabolism, RNA binding, endoplasmic reticulum or Golgi function, synaptic function, ion channel, and transporter. In contrast, fewer genes were down-regulated in the imprinting, coinciding with the previous data that the total RNA synthesis increased associated with filial imprinting. Our data suggests that the filial imprinting involves the modulation of multiple signaling pathways.

  16. RNA-FISH to analyze allele-specific expression.

    PubMed

    Braidotti, G

    2001-01-01

    One of the difficulties associated with the analysis of imprinted gene expression is the need to distinguish RNA synthesis occurring at the maternal vs the paternally inherited copy of the gene. Most of the techniques used to examine allele-specific expression exploit naturally occurring polymorphisms and measure steady-state levels of RNA isolated from a pool of cells. Hence, a restriction fragment length polymorphism (RFLP) an be exploited in a heterozygote, by a reverse transcriptase polymerase chain reaction (RT-PCR)- based procedure, to analyze maternal vs paternal gene expression. The human IGF2R gene was analyzed in this way. Smrzka et al. (1) were thus able to show that the IGF2R gene possesses a hemimethylated, intronic CpG island analogous to the mouse imprinting box. However, IGF2R mRNA was detected that possessed the RFLP from both the maternal and paternal alleles in all but one of the 70 lymphoblastoid samples. (The one monoallelic sample reactivated its paternal allele with continued cell culturing.) It was concluded that monoallelic expression of the human gene is a polymorphic trait occurring in a small minority of all tested samples (reviewed in refs. 2,3). Although this is a sound conclusion, the question remains: Is the human IGF2R gene imprinted?

  17. The effects of maternal anxiety during pregnancy on IGF2/H19 methylation in cord blood

    PubMed Central

    Mansell, T; Novakovic, B; Meyer, B; Rzehak, P; Vuillermin, P; Ponsonby, A-L; Collier, F; Burgner, D; Saffery, R; Ryan, J; Vuillermin, Peter; Ponsonby, Anne-Louise; Carlin, John B; Allen, Katie J; Tang, Mimi L; Saffery, Richard; Ranganathan, Sarath; Burgner, David; Dwyer, Terry; Jachno, Kim; Sly, Peter

    2016-01-01

    Compelling evidence suggests that maternal mental health in pregnancy can influence fetal development. The imprinted genes, insulin-like growth factor 2 (IGF2) and H19, are involved in fetal growth and each is regulated by DNA methylation. This study aimed to determine the association between maternal mental well-being during pregnancy and differentially methylated regions (DMRs) of IGF2 (DMR0) and the IGF2/H19 imprinting control region (ICR) in newborn offspring. Maternal depression, anxiety and perceived stress were assessed at 28 weeks of pregnancy in the Barwon Infant Study (n=576). DNA methylation was measured in purified cord blood mononuclear cells using the Sequenom MassArray Platform. Maternal anxiety was associated with a decrease in average ICR methylation (Δ=−2.23% 95% CI=−3.68 to −0.77%), and across all six of the individual CpG units in anxious compared with non-anxious groups. Birth weight and sex modified the association between prenatal anxiety and infant methylation. When stratified into lower (⩽3530 g) and higher (>3530 g) birth weight groups using the median birth weight, there was a stronger association between anxiety and ICR methylation in the lower birth weight group (Δ=−3.89% 95% CI=−6.06 to −1.72%), with no association in the higher birth weight group. When stratified by infant sex, there was a stronger association in female infants (Δ=−3.70% 95% CI=−5.90 to −1.51%) and no association in males. All the linear regression models were adjusted for maternal age, smoking and folate intake. These findings show that maternal anxiety in pregnancy is associated with decreased IGF2/H19 ICR DNA methylation in progeny at birth, particularly in female, low birth weight neonates. ICR methylation may help link poor maternal mental health and adverse birth outcomes, but further investigation is needed. PMID:27023171

  18. Expression of imprinted genes in placenta is associated with infant neurobehavioral development

    PubMed Central

    Green, Benjamin B; Kappil, Maya; Lambertini, Luca; Armstrong, David A; Guerin, Dylan J; Sharp, Andrew J; Lester, Barry M; Chen, Jia; Marsit, Carmen J

    2015-01-01

    Genomic imprinting disorders often exhibit delayed neurobehavioral development, suggesting this unique mechanism of epigenetic regulation plays a role in mental and neurological health. While major errors in imprinting have been linked to adverse health outcomes, there has been little research conducted on how moderate variability in imprinted gene expression within a population contributes to differences in neurobehavioral outcomes, particularly at birth. Here, we profiled the expression of 108 known and putative imprinted genes in human placenta samples from 615 infants assessed by the Neonatal Intensive Care Unit (NICU) Network Neurobehavioral Scales (NNNS). Data reduction identified 10 genes (DLX5, DHCR24, VTRNA2-1, PHLDA2, NPAP1, FAM50B, GNAS-AS1, PAX8-AS1, SHANK2, and COPG2IT1) whose expression could distinguish between newborn neurobehavioral profiles derived from the NNNS. Clustering infants based on the expression pattern of these genes identified 2 groups of infants characterized by reduced quality of movement, increased signs of asymmetrical and non-optimal reflexes, and increased odds of demonstrating increased signs of physiologic stress and abstinence. Overall, these results suggest that common variation in placental imprinted gene expression is linked to suboptimal performance on scales of neurological functioning as well as with increased signs of physiologic stress, highlighting the central importance of the control of expression of these genes in the placenta for neurobehavioral development. PMID:26198301

  19. The origin and evolution of genomic imprinting and viviparity in mammals

    PubMed Central

    Renfree, Marilyn B.; Suzuki, Shunsuke; Kaneko-Ishino, Tomoko

    2013-01-01

    Genomic imprinting is widespread in eutherian mammals. Marsupial mammals also have genomic imprinting, but in fewer loci. It has long been thought that genomic imprinting is somehow related to placentation and/or viviparity in mammals, although neither is restricted to mammals. Most imprinted genes are expressed in the placenta. There is no evidence for genomic imprinting in the egg-laying monotreme mammals, despite their short-lived placenta that transfers nutrients from mother to embryo. Post natal genomic imprinting also occurs, especially in the brain. However, little attention has been paid to the primary source of nutrition in the neonate in all mammals, the mammary gland. Differentially methylated regions (DMRs) play an important role as imprinting control centres in each imprinted region which usually comprises both paternally and maternally expressed genes (PEGs and MEGs). The DMR is established in the male or female germline (the gDMR). Comprehensive comparative genome studies demonstrated that two imprinted regions, PEG10 and IGF2-H19, are conserved in both marsupials and eutherians and that PEG10 and H19 DMRs emerged in the therian ancestor at least 160 Ma, indicating the ancestral origin of genomic imprinting during therian mammal evolution. Importantly, these regions are known to be deeply involved in placental and embryonic growth. It appears that most maternal gDMRs are always associated with imprinting in eutherian mammals, but emerged at differing times during mammalian evolution. Thus, genomic imprinting could evolve from a defence mechanism against transposable elements that depended on DNA methylation established in germ cells. PMID:23166401

  20. The origin and evolution of genomic imprinting and viviparity in mammals.

    PubMed

    Renfree, Marilyn B; Suzuki, Shunsuke; Kaneko-Ishino, Tomoko

    2013-01-05

    Genomic imprinting is widespread in eutherian mammals. Marsupial mammals also have genomic imprinting, but in fewer loci. It has long been thought that genomic imprinting is somehow related to placentation and/or viviparity in mammals, although neither is restricted to mammals. Most imprinted genes are expressed in the placenta. There is no evidence for genomic imprinting in the egg-laying monotreme mammals, despite their short-lived placenta that transfers nutrients from mother to embryo. Post natal genomic imprinting also occurs, especially in the brain. However, little attention has been paid to the primary source of nutrition in the neonate in all mammals, the mammary gland. Differentially methylated regions (DMRs) play an important role as imprinting control centres in each imprinted region which usually comprises both paternally and maternally expressed genes (PEGs and MEGs). The DMR is established in the male or female germline (the gDMR). Comprehensive comparative genome studies demonstrated that two imprinted regions, PEG10 and IGF2-H19, are conserved in both marsupials and eutherians and that PEG10 and H19 DMRs emerged in the therian ancestor at least 160 Ma, indicating the ancestral origin of genomic imprinting during therian mammal evolution. Importantly, these regions are known to be deeply involved in placental and embryonic growth. It appears that most maternal gDMRs are always associated with imprinting in eutherian mammals, but emerged at differing times during mammalian evolution. Thus, genomic imprinting could evolve from a defence mechanism against transposable elements that depended on DNA methylation established in germ cells.

  1. Phosphatidylinositol 3-Kinase (PI3K) Signaling via Glycogen Synthase Kinase-3 (Gsk-3) Regulates DNA Methylation of Imprinted Loci*

    PubMed Central

    Popkie, Anthony P.; Zeidner, Leigh C.; Albrecht, Ashley M.; D'Ippolito, Anthony; Eckardt, Sigrid; Newsom, David E.; Groden, Joanna; Doble, Bradley W.; Aronow, Bruce; McLaughlin, K. John; White, Peter; Phiel, Christopher J.

    2010-01-01

    Glycogen synthase kinase-3 (Gsk-3) isoforms, Gsk-3α and Gsk-3β, are constitutively active, largely inhibitory kinases involved in signal transduction. Underscoring their biological significance, altered Gsk-3 activity has been implicated in diabetes, Alzheimer disease, schizophrenia, and bipolar disorder. Here, we demonstrate that deletion of both Gsk-3α and Gsk-3β in mouse embryonic stem cells results in reduced expression of the de novo DNA methyltransferase Dnmt3a2, causing misexpression of the imprinted genes Igf2, H19, and Igf2r and hypomethylation of their corresponding imprinted control regions. Treatment of wild-type embryonic stem cells and neural stem cells with the Gsk-3 inhibitor, lithium, phenocopies the DNA hypomethylation at these imprinted loci. We show that inhibition of Gsk-3 by phosphatidylinositol 3-kinase (PI3K)-mediated activation of Akt also results in reduced DNA methylation at these imprinted loci. Finally, we find that N-Myc is a potent Gsk-3-dependent regulator of Dnmt3a2 expression. In summary, we have identified a signal transduction pathway that is capable of altering the DNA methylation of imprinted loci. PMID:21047779

  2. Frequency and timing of loss of imprinting at 11p13 and 11p15 in Wilms' tumor development.

    PubMed

    Brown, Keith W; Power, Frances; Moore, Beth; Charles, Adrian K; Malik, Karim T A

    2008-07-01

    Epigenetic changes occur frequently in Wilms' tumor (WT), especially loss of imprinting (LOI) of IGF2/H19 at 11p15. Our previous results have identified imprinted transcripts (WT1-AS and AWT1) from the WT1 locus at 11p13 and showed LOI of these in some WTs. In this article, we set out to test the relationship between LOI at 11p13 and 11p15 and their timing in WT progression relative to other genetic changes. We found a higher level (83%) of 11p13 LOI in WT than of 11p15 LOI (71%). There was no correlation between methylation levels at the 11p13 and 11p15 differentially methylated regions or between allelic expression of WT1-AS/AWT1 and IGF2. Interestingly, retention of normal imprinting at 11p13 was associated with a small group of relatively late-onset, high-stage WTs. An examination of genetic and epigenetic alterations in nephrogenic rests, which are premalignant WT precursors, showed that LOI at both 11p13 and 11p15 occurred before either 16q loss of heterozygosity (LOH) or 7p LOH. This suggests that these LOH events are very unlikely to be a cause of LOI but that LOH may act by potentiating the effects of overexpression of IGF2 and/or WT1-AS/AWT1 that result from LOI.

  3. Using RNA sequencing for identifying gene imprinting and random monoallelic expression in human placenta

    PubMed Central

    Metsalu, Tauno; Viltrop, Triin; Tiirats, Airi; Rajashekar, Balaji; Reimann, Ene; Kõks, Sulev; Rull, Kristiina; Milani, Lili; Acharya, Ganesh; Basnet, Purusotam; Vilo, Jaak; Mägi, Reedik; Metspalu, Andres; Peters, Maire; Haller-Kikkatalo, Kadri; Salumets, Andres

    2014-01-01

    Given the possible critical importance of placental gene imprinting and random monoallelic expression on fetal and infant health, most of those genes must be identified, in order to understand the risks that the baby might meet during pregnancy and after birth. Therefore, the aim of the current study was to introduce a workflow and tools for analyzing imprinted and random monoallelic gene expression in human placenta, by applying whole-transcriptome (WT) RNA sequencing of placental tissue and genotyping of coding DNA variants in family trios. Ten family trios, each with a healthy spontaneous single-term pregnancy, were recruited. Total RNA was extracted for WT analysis, providing the full sequence information for the placental transcriptome. Parental and child blood DNA genotypes were analyzed by exome SNP genotyping microarrays, mapping the inheritance and estimating the abundance of parental expressed alleles. Imprinted genes showed consistent expression from either parental allele, as demonstrated by the SNP content of sequenced transcripts, while monoallelically expressed genes had random activity of parental alleles. We revealed 4 novel possible imprinted genes (LGALS8, LGALS14, PAPPA2 and SPTLC3) and confirmed the imprinting of 4 genes (AIM1, PEG10, RHOBTB3 and ZFAT-AS1) in human placenta. The major finding was the identification of 4 genes (ABP1, BCLAF1, IFI30 and ZFAT) with random allelic bias, expressing one of the parental alleles preferentially. The main functions of the imprinted and monoallelically expressed genes included: i) mediating cellular apoptosis and tissue development; ii) regulating inflammation and immune system; iii) facilitating metabolic processes; and iv) regulating cell cycle. PMID:25437054

  4. MicroRNA Let-7b inhibits keratinocyte migration in cutaneous wound healing by targeting IGF2BP2.

    PubMed

    Wu, Yan; Zhong, Julia Li; Hou, Ning; Sun, Yaolan; Ma, Benting; Nisar, Muhammad Farrukh; Teng, Yan; Tan, Zhaoli; Chen, Keping; Wang, Youliang; Yang, Xiao

    2017-02-01

    Wound healing is a complex process which involves proliferation and migration of keratinocyte for closure of epidermal injuries. A member of microRNA family, let-7b, has been expressed in mammalian skin, but its exact role in keratinocyte migration is still not in knowledge. Here, we showed that let-7b regulates keratinocyte migration by targeting the insulin-like growth factor IGF2BP2. Overexpression of let-7b led to reduced HaCaT cell migration, while knockdown of let-7b resulted in enhanced migration. Furthermore, let-7b was decreased during wound healing in wild-type mice, which led us to construct the transgenic mice with overexpression of let-7b in skin. The re-epithelialization of epidermis of let-7b transgenic mice was reduced during wound healing. Using bioinformatics prediction software and a reporter gene assay, we found that IGF2BP2 was a target of let-7b, which contributes to keratinocyte migration. Introduction of an expression vector of IGF2BP2 also rescued let-7b-induced migration deficiency, which confirms that IGF2BP2 is an important target for let-7b regulation. Our findings suggest that let-7b significantly delayed the re-epithelialization possibly due to reduction of keratinocyte migration and restraints IGF2BP2 during skin wound healing.

  5. 5‑Azacytidine inhibits human rhabdomyosarcoma cell growth by downregulating insulin‑like growth factor 2 expression and reactivating the H19 gene product miR‑675, which negatively affects insulin‑like growth factors and insulin signaling.

    PubMed

    Tarnowski, Maciej; Tkacz, Marta; Czerewaty, Michał; Poniewierska-Baran, Agata; Grymuła, Katarzyna; Ratajczak, Mariusz Z

    2015-05-01

    Insulin-like growth factor 2 (IGF2) and 1 (IGF1) and insulin (INS) promote proliferation of rhabdomyosarcoma (RMS) cells by interacting with the insulin-like growth factor 1 receptor (IGF1R) and the insulin receptor (INSR). Loss of imprinting (LOI) by DNA hypermethylation at the differentially methylated region (DMR) for the IGF2‑H19 locus is commonly observed in RMS cells and results in an increase in the expression of proliferation-promoting IGF2 and downregulation of proliferation-inhibiting non-coding H19 miRNAs. One of these miRNAs, miR‑675, has been reported in murine cells to be a negative regulator of IGF1R expression. To better address the role of IGF2 and 1, as well as INS signaling in the pathogenesis of RMS and the involvement of LOI at the IGF2‑H19 locus, we employed the DNA demethylating agent 5‑azacytidine (AzaC). We observed that AzaC‑mediated demethylation of the DMR at the IGF2‑H19 locus resulted in downregulation of IGF2 and an increase in the expression of H19. This epigenetic change resulted in a decrease in RMS proliferation due to downregulation of IGF2 and, IGF1R expression in an miR‑675‑dependent manner. Interestingly, we observed that miR‑675 not only inhibited the expression of IGF1R in a similar manner in human and murine cells, but we also observed its negative effect on the expression of the INSR. These results confirm the crucial role of LOI at the IGF2‑H19 DMR in the pathogenesis of RMS and are relevant to the development of new treatment strategies.

  6. Allele-specific H3K79 Di- versus trimethylation distinguishes opposite parental alleles at imprinted regions.

    PubMed

    Singh, Purnima; Han, Li; Rivas, Guillermo E; Lee, Dong-Hoon; Nicholson, Thomas B; Larson, Garrett P; Chen, Taiping; Szabó, Piroska E

    2010-06-01

    Imprinted gene expression corresponds to parental allele-specific DNA CpG methylation and chromatin composition. Histone tail covalent modifications have been extensively studied, but it is not known whether modifications in the histone globular domains can also discriminate between the parental alleles. Using multiplex chromatin immunoprecipitation-single nucleotide primer extension (ChIP-SNuPE) assays, we measured the allele-specific enrichment of H3K79 methylation and H4K91 acetylation along the H19/Igf2 imprinted domain. Whereas H3K79me1, H3K79me2, and H4K91ac displayed a paternal-specific enrichment at the paternally expressed Igf2 locus, H3K79me3 was paternally biased at the maternally expressed H19 locus, including the paternally methylated imprinting control region (ICR). We found that these allele-specific differences depended on CTCF binding in the maternal ICR allele. We analyzed an additional 11 differentially methylated regions (DMRs) and found that, in general, H3K79me3 was associated with the CpG-methylated alleles, whereas H3K79me1, H3K79me2, and H4K91ac enrichment was specific to the unmethylated alleles. Our data suggest that allele-specific differences in the globular histone domains may constitute a layer of the "histone code" at imprinted genes.

  7. Ammonium accumulation and use of mineral oil overlay do not alter imprinting establishment at three key imprinted genes in mouse oocytes grown and matured in a long-term follicle culture.

    PubMed

    Anckaert, Ellen; Adriaenssens, Tom; Romero, Sergio; Smitz, Johan

    2009-10-01

    Imprinted genes are differentially methylated during gametogenesis to allow parent-of-origin-specific monoallelic expression. Follicle culture under oil overlay has been associated with altered imprinting establishment in mouse oocytes. We previously demonstrated normal imprinting establishment at four key imprinted genes in mouse oocytes grown and matured in a long-term in vitro follicle culture system without oil overlay. Ammonium (300 microM) has been linked to aberrant imprinting in in vitro preimplantation embryo culture. Compared to culture without oil, mineral oil overlay during follicle culture led to a dramatic increase in ammonia levels in culture medium: mean ammonia levels were, respectively, 39 and 290 microM at Day 4 of culture, 73 and 465 microM at Day 8, and 101 and 725 microM at Day 12 (P < 0.0001). Mineral oil overlay and high ammonia levels (comparable to the follicle culture system for which aberrant imprinting was previously described) during follicle culture did not affect follicle survival, metaphase II (MII) rate, or MII oocyte diameter. Bisulphite sequencing revealed that high levels of ammonia and mineral oil overlay during follicle culture did not alter the methylation status of differentially methylated regions of three key imprinted genes (Snrpn, Igf2r, and H19) in MII oocytes. In the current culture setup, ammonium accumulation and mineral oil overlay during follicle culture do not induce aberrant imprinting establishment at the studied regulatory sequences in mouse oocytes.

  8. Early embryonic failure: Expression and imprinted status of candidate genes on human chromosome 21

    SciTech Connect

    Sherman, L.S.; Bennett, P.R.; Moore, G.E.

    1994-09-01

    Two cases of maternal uniparental (hetero)disomy for human chromosome 21 (mUPD21) have been identified in a systematic search for UPD in 23 cases of early embryonic failure (EEF). Bi-parental origin of the other chromosome pairs was confirmed using specific VNTR probes or dinucleotide repeat analysis. Both maternally and paternally derived isochromosomes 21q have previously been identified in two individuals with normal phenotypes. Full UPD21 has a different mechanism of origin than uniparental isochromosome 21q and its effect on imprinted genes and phenotypic outcome will therefore not necessarily be the same. EEF associated with mUPD21 suggests that developmentally important genes on HSA 21 may be imprinted such that they are only expressed from either the maternally or paternally derived alleles. We have searched for monoallelic expression of candidate genes on HSA 21 in human pregnancy (CBS, IFNAR, COL6A1) using intragenic DNA polymorphisms. These genes were chosen either because their murine homologues lie in imprinted regions or because they are potentially important in embryogenesis. Once imprinted candidate genes have been identified, their methylation status and expression in normal, early embryonic failure and uniparental disomy 21 pregnancies will be studied. At the same time, a larger number of cases of EEF are being examined to further investigate the incidence of UPD21 in this group.

  9. Expression of Ki-67 as proliferation biomarker in imprint smears of endometrial carcinoma.

    PubMed

    Konstantinos, Kosmas; Marios, Stamoulas; Anna, Marouga; Nikolaos, Kavantzas; Efstratios, Patsouris; Paulina, Athanassiadou

    2013-03-01

    The aims of this study were to determine the expression of Ki-67 in type I and type II endometrial adenocarcinomas as well as normal endometrium in imprint smears and to correlate the results with clinicopathologic parameters of primary untreated endometrial cancer patients. During a 29-month period, 255 patients were evaluated with entometrial imprint cytology. Endometrial samples freshly resected from women who underwent total abdominal hysterectomy were studied. One hundred twenty-six patients had endometrial carcinoma and 129 cases were diagnosed as normal endometrium. The expression of Ki-67 was assessed by immunocytochemistry. Positive staining was correlated with increased stage, grade and lymph node metastases. High expression was more frequent in type II than type I endometrial adenocarcinoma and high-grade endometrial carcinoma had higher proportions of Ki-67 positive immunostaining compared with low-grade carcinoma. Proliferative endometrium showed high Ki-67 expression level, even higher than those of grade 1 and type I. On the other hand, secretory endometrium Ki-67 positive cells were markedly diminished and even disappeared. Completely negative staining was found to be related to atrophic endometrium. Immunocytochemical findings from Ki-67 stain, in addition to cytomorphologic features, appeared to be useful for the diagnosis of endometrial carcinoma in endometrial cytology with imprint smears. High Ki-67 expression correlates with morphologic features of aggressiveness and the expression pattern of Ki-67 correspond to the expected cyclic/atrophic pattern in normal endometrium.

  10. Coadaptation in mother and infant regulated by a paternally expressed imprinted gene.

    PubMed Central

    Curley, James P.; Barton, Sheila; Surani, Azim; Keverne, Eric B.

    2004-01-01

    This study investigates how a targeted mutation of a paternally expressed imprinted gene regulates multiple aspects of foetal and post-natal development including placental size, foetal growth, suckling and post-natal growth, weaning age and puberty onset. This same mutation in a mother impairs maternal reproductive success with reduced maternal care, reduced maternal food intake during pregnancy, and impaired milk let-down, which in turn reduces infant growth and delays weaning and onset of puberty. The significance of these coadaptive traits being synchronized in mother and offspring by the same paternally expressed imprinted gene ensures that offspring that have extracted 'good' maternal nurturing will themselves be both well provisioned and genetically predisposed towards 'good' mothering. PMID:15306355

  11. Variation in the IGF2 gene promoter region is associated with intramuscular fat content in porcine skeletal muscle.

    PubMed

    Aslan, Ozlem; Hamill, Ruth M; Davey, Grace; McBryan, Jean; Mullen, Anne Maria; Gispert, Marina; Sweeney, Torres

    2012-04-01

    Intramuscular fat (IMF) and subcutaneous fat (back fat-BF) are two of the major fat depots in livestock. A QTN located in the insulin-like growth factor 2 gene (IGF2) has been associated with a desirable reduction in BF depth in pigs. Given that the lipid metabolism of intramuscular adipocytes differs from that of subcutaneous fat adipocytes, this study aimed to search for genetic variation in the IGF2 gene that may be associated with IMF, as well as BF, in diverse pig breeds. Four proximal promoter regions of the IGF2 gene were characterised and the association of IGF2 genetic variation with IMF and BF was assessed. Six promoter SNPs were identified in four promoter regions (P1-P4; sequence coverage 945, 866, 784 and 864 bp, respectively) in phenotypically diverse F1 cross populations. Three promoter SNPs were subsequently genotyped in three pure breeds (Pietrain = 98, Duroc = 99 and Large White = 98). All three SNPs were >95% monomorphic in the Pietrain and Duroc breeds but minor alleles were at moderate frequencies in the Large White breed. These SNPs were linked and one was located in a putative transcription factor binding site. Five haplotypes were inferred and three combined diplotypes tested for association with IMF and BF in the Large White. As expected haplotype 1 (likely in LD with the beneficial QTN allele) was superior for BF level. In contrast, the heterozygote diplotype of the most common haplotypes (1 and 2) was associated with higher IMF and marbling scores compared to either homozygote. Gene expression analysis of divergent animals showed that IGF2 was 1.89 fold up-regulated in muscle with higher compared to lower IMF content. These findings suggest that genetic variation in the promoter region of the IGF2 gene is associated with IMF content in porcine skeletal muscle and that greater expression of the IGF2 gene is associated with higher IMF content.

  12. Genomic imprinting syndromes and cancer.

    PubMed

    Lim, Derek Hock Kiat; Maher, Eamonn Richard

    2010-01-01

    Genomic imprinting represents a form of epigenetic control of gene expression in which one allele of a gene is preferentially expressed according to the parent-of-origin of the allele. Genomic imprinting plays an important role in normal growth and development. Disruption of imprinting can result in a number of human imprinting syndromes and predispose to cancer. In this chapter, we describe a number of human imprinting syndromes to illustrate the concepts of genomic imprinting and how loss of imprinting of imprinted genes their relationship to human neoplasia.

  13. The rs11705701 G>A Polymorphism of IGF2BP2 is Associated With IGF2BP2 mRNA and Protein Levels in the Visceral Adipose Tissue - A Link to Type 2 Diabetes Susceptibility

    PubMed Central

    Chistiakov, Dimitry A.; Nikitin, Alexey G.; Smetanina, Svetlana A.; Bel'chikova, Larisa N.; Suplotova, Lyudmila A.; Shestakova, Marina V.; Nosikov, Valery V.

    2012-01-01

    BACKGROUND: Insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) regulates translation of IGF2, a growth factor that plays a key role in controlling fetal growth and organogenesis including adipogenesis and pancreatic development. In Caucasians, the rs4402960 G>T polymorphism of IGF2BP2 has been shown to predispose to type 2 diabetes (T2D) in multiple populations. In this study, we tested whether rs4402960 G>T and rs11705701 G>A contribute to the development of T2D in a Russian population. METHODS: Both markers were genotyped in Russian diabetic (n = 1,470) and non-diabetic patients (n = 1,447) using a Taqman allele discrimination assay. The odds ratio (OR) for the risk of developing T2D was calculated using logistic regression assuming an additive genetic model adjusted for age, sex, HbA1c, hypertension, obesity, and body mass index (BMI). Multivariate linear regression analyses were used to test genotype-phenotype correlations, and adjusted for age, sex, hypertension, obesity, and BMI. Expression of IGF2BP2 in the visceral adipose tissue was quantified using real-time PCR. The content of IGF2BP2 protein and both its isoforms (p58 and p66) in the adipose tissue was measured using Western blot analysis. RESULTS: There was no significant association between rs4402960 and T2D. Whereas, allele A of rs11705701 was associated with higher T2D risk (OR = 1.19, p < 0.001). Diabetic and non-diabetic carriers of genotype TT (rs4402960) had significantly increased HOMA-IR (p = 0.033 and p = 0.031, respectively). Non-diabetic patients homozygous for AA (rs11705701) had higher HOMA-IR (p = 0.04), lower HOMA-β (p = 0.012), and reduced 2-h insulin levels (p = 0.016). Non-obese individuals (diabetic and non-diabetic) homozygous for either AA (rs11705701) or TT (rs4402960) had higher levels of IGF2BP2 mRNA in the adipose tissue than other IGF2BP2 variants. Also, allele A of rs11705701 was associated with reduced amounts of the short isoform (p58) and increased levels of

  14. The oncogenic triangle of HMGA2, LIN28B and IGF2BP1 antagonizes tumor-suppressive actions of the let-7 family

    PubMed Central

    Busch, Bianca; Bley, Nadine; Müller, Simon; Glaß, Markus; Misiak, Danny; Lederer, Marcell; Vetter, Martina; Strauß, Hans-Georg; Thomssen, Christoph; Hüttelmaier, Stefan

    2016-01-01

    The tumor-suppressive let-7 microRNA family targets various oncogene-encoding mRNAs. We identify the let-7 targets HMGA2, LIN28B and IGF2BP1 to form a let-7 antagonizing self-promoting oncogenic triangle. Surprisingly, 3′-end processing of IGF2BP1 mRNAs is unaltered in aggressive cancers and tumor-derived cells although IGF2BP1 synthesis was proposed to escape let-7 attack by APA-dependent (alternative polyadenylation) 3′ UTR shortening. However, the expression of the triangle factors is inversely correlated with let-7 levels and promoted by LIN28B impairing let-7 biogenesis. Moreover, IGF2BP1 enhances the expression of all triangle factors by recruiting the respective mRNAs in mRNPs lacking AGO proteins and let-7 miRNAs. This indicates that the downregulation of let-7, largely facilitated by LIN28B upregulation, and the protection of let-7 target mRNAs by IGF2BP1-directed shielding in mRNPs synergize in enhancing the expression of triangle factors. The oncogenic potential of this triangle was confirmed in ovarian cancer (OC)-derived ES-2 cells transduced with let-7 targeting decoys. In these, the depletion of HMGA2 only diminishes tumor cell growth under permissive conditions. The depletion of LIN28B and more prominently IGF2BP1 severely impairs tumor cell viability, self-renewal and 2D as well as 3D migration. In conclusion, this suggests the targeting of the HMGA2-LIN28B-IGF2BP1 triangle as a promising strategy in cancer treatment. PMID:26917013

  15. ZFP57 maintains the parent-of-origin-specific expression of the imprinted genes and differentially affects non-imprinted targets in mouse embryonic stem cells

    PubMed Central

    Riso, Vincenzo; Cammisa, Marco; Kukreja, Harpreet; Anvar, Zahra; Verde, Gaetano; Sparago, Angela; Acurzio, Basilia; Lad, Shraddha; Lonardo, Enza; Sankar, Aditya; Helin, Kristian; Feil, Robert; Fico, Annalisa; Angelini, Claudia; Grimaldi, Giovanna; Riccio, Andrea

    2016-01-01

    ZFP57 is necessary for maintaining repressive epigenetic modifications at Imprinting control regions (ICRs). In mouse embryonic stem cells (ESCs), ZFP57 binds ICRs (ICRBS) and many other loci (non-ICRBS). To address the role of ZFP57 on all its target sites, we performed high-throughput and multi-locus analyses of inbred and hybrid mouse ESC lines carrying different gene knockouts. By using an allele-specific RNA-seq approach, we demonstrate that ZFP57 loss results in derepression of the imprinted allele of multiple genes in the imprinted clusters. We also find marked epigenetic differences between ICRBS and non-ICRBS suggesting that different cis-acting regulatory functions are repressed by ZFP57 at these two classes of target loci. Overall, these data demonstrate that ZFP57 is pivotal to maintain the allele-specific epigenetic modifications of ICRs that in turn are necessary for maintaining the imprinted expression over long distances. At non-ICRBS, ZFP57 inactivation results in acquisition of epigenetic features that are characteristic of poised enhancers, suggesting that another function of ZFP57 in early embryogenesis is to repress cis-acting regulatory elements whose activity is not yet required. PMID:27257070

  16. Dynamic expression of imprinted genes associates with maternally controlled nutrient allocation during maize endosperm development.

    PubMed

    Xin, Mingming; Yang, Ruolin; Li, Guosheng; Chen, Hao; Laurie, John; Ma, Chuang; Wang, Dongfang; Yao, Yingyin; Larkins, Brian A; Sun, Qixin; Yadegari, Ramin; Wang, Xiangfeng; Ni, Zhongfu

    2013-09-01

    In angiosperms, the endosperm provides nutrients for embryogenesis and seed germination and is the primary tissue where gene imprinting occurs. To identify the imprintome of early developing maize (Zea mays) endosperm, we performed high-throughput transcriptome sequencing of whole kernels at 0, 3, and 5 d after pollination (DAP) and endosperms at 7, 10, and 15 DAP, using B73 by Mo17 reciprocal crosses. We observed gradually increased expression of paternal transcripts in 3- and 5-DAP kernels. In 7-DAP endosperm, the majority of the genes tested reached a 2:1 maternal versus paternal ratio, suggesting that paternal genes are nearly fully activated by 7 DAP. A total of 116, 234, and 63 genes exhibiting parent-specific expression were identified at 7, 10, and 15 DAP, respectively. The largest proportion of paternally expressed genes was at 7 DAP, mainly due to the significantly deviated parental allele expression ratio of these genes at this stage, while nearly 80% of the maternally expressed genes (MEGs) were specific to 10 DAP and were primarily attributed to sharply increased expression levels compared with the other stages. Gene ontology enrichment analysis of the imprinted genes suggested that 10-DAP endosperm-specific MEGs are involved in nutrient uptake and allocation and the auxin signaling pathway, coincident with the onset of starch and storage protein accumulation.

  17. Imprinting defects at human 14q32 locus alters gene expression and is associated with the pathobiology of osteosarcoma

    PubMed Central

    Shu, Jingmin; Li, Lihua; Sarver, Anne E.; Pope, Emily A.; Varshney, Jyotika; Thayanithy, Venugopal; Spector, Logan; Largaespada, David A.; Steer, Clifford J.; Subramanian, Subbaya

    2016-01-01

    Osteosarcoma is the most common primary bone malignancy affecting children and adolescents. Although several genetic predisposing conditions have been associated with osteosarcoma, our understanding of its pathobiology is rather limited. Here we show that, first, an imprinting defect at human 14q32-locus is highly prevalent (87%) and specifically associated with osteosarcoma patients < 30 years of age. Second, the average demethylation at differentially methylated regions (DMRs) in the 14q32-locus varied significantly compared to genome-wide demethylation. Third, the 14q32-locus was enriched in both H3K4-me3 and H3K27-me3 histone modifications that affected expression of all imprinted genes and miRNAs in this region. Fourth, imprinting defects at 14q32 - DMRs are present in triad DNA samples from affected children and their biological parents. Finally, imprinting defects at 14q32-DMRs were also observed at higher frequencies in an Rb1/Trp53 mutation-induced osteosarcoma mouse model. Further analysis of normal and tumor tissues from a Sleeping Beauty mouse model of spontaneous osteosarcoma supported the notion that these imprinting defects may be a key factor in osteosarcoma pathobiology. In conclusion, we demonstrate that imprinting defects at the 14q32 locus significantly alter gene expression, may contribute to the pathogenesis of osteosarcoma, and could be predictive of survival outcomes. PMID:26802029

  18. Differential methylation status of IGF2-H19 locus does not affect the fertility of crossbred bulls but some of the CTCF binding sites could be potentially important.

    PubMed

    Jena, Subas C; Kumar, Sandeep; Rajput, Sandeep; Roy, Bhaskar; Verma, Arpana; Kumaresan, Arumugam; Mohanty, Tushar K; De, Sachinandan; Kumar, Rakesh; Datta, Tirtha K

    2014-04-01

    Associations between abnormal methylation of spermatozoan DNA with male infertility have been sought in recent years to identify a molecular explanation of differential spermatozoan function. The present work was undertaken to investigate the methylation profile of differentially methylated regions (DMRs) in the IGF2-H19 locus of Bos taurus X Bos indicus crossbred bull spermatozoa. Bulls having more than at least 100 insemination records over a period of 12 years were classified into two groups of five bulls each belonging to low- and high-fertility groups. The IGF2 and H19 DMR sequences in B. indicus cattle were observed to be in absolute homology with B. taurus cattle. The DNA of crossbred bull spermatozoa was isolated, bisulfite treated, and amplified for specific DMR regions using methylation-change-specific primers. The overall degree of methylation at IGF2-H19 DMRs was not found to be significantly different among two groups of bulls. The sixth CTCF binding site (CCCTC) identified in H19 DMR, however, had a significant methylation difference between the high- and low-fertility bulls. It was concluded that alteration of the methylation levels at IGF2-H19 DMRs might not be responsible for the fertility difference of crossbred bulls, although the role played by the specific CTCF binding sites at this locus, which could influence IGF2 expression during spermatogenesis and early embryonic development, deserves further attention.

  19. Visualizing Changes in Cdkn1c Expression Links Early-Life Adversity to Imprint Mis-regulation in Adults.

    PubMed

    Van de Pette, Mathew; Abbas, Allifia; Feytout, Amelie; McNamara, Gráinne; Bruno, Ludovica; To, Wilson K; Dimond, Andrew; Sardini, Alessandro; Webster, Zoe; McGinty, James; Paul, Eleanor J; Ungless, Mark A; French, Paul M W; Withers, Dominic J; Uren, Anthony; Ferguson-Smith, Anne C; Merkenschlager, Matthias; John, Rosalind M; Fisher, Amanda G

    2017-01-31

    Imprinted genes are regulated according to parental origin and can influence embryonic growth and metabolism and confer disease susceptibility. Here, we designed sensitive allele-specific reporters to non-invasively monitor imprinted Cdkn1c expression in mice and showed that expression was modulated by environmental factors encountered in utero. Acute exposure to chromatin-modifying drugs resulted in de-repression of paternally inherited (silent) Cdkn1c alleles in embryos that was temporary and resolved after birth. In contrast, deprivation of maternal dietary protein in utero provoked permanent de-repression of imprinted Cdkn1c expression that was sustained into adulthood and occurred through a folate-dependent mechanism of DNA methylation loss. Given the function of imprinted genes in regulating behavior and metabolic processes in adults, these results establish imprinting deregulation as a credible mechanism linking early-life adversity to later-life outcomes. Furthermore, Cdkn1c-luciferase mice offer non-invasive tools to identify factors that disrupt epigenetic processes and strategies to limit their long-term impact.

  20. Paternal BPA exposure in early life alters Igf2 epigenetic status in sperm and induces pancreatic impairment in rat offspring.

    PubMed

    Mao, Zhenxing; Xia, Wei; Chang, Huailong; Huo, Wenqian; Li, Yuanyuan; Xu, Shunqing

    2015-11-04

    Exposure to endocrine disruptors in utero appears to alter epigenetics in the male germ-line and subsequently promote adult-onset disease in subsequent generations. Fetal exposure to bisphenol A (BPA), a highly prevalent endocrine disruptor in environment, has been shown to alter epigenetic modification and result in glucose intolerance in adulthood. However, whether fetal exposure to BPA can induce epigenetic modification and phenotypic changes in their subsequent offspring are still unclear. The present study was designed to investigate whether exposure to BPA in early life induced glucose intolerance in the offspring through male germ line, and the underlying epigenetic molecular basis. F0 pregnant SD rats were received corn oil or 40 μg/kg/day of BPA during gestation and lactation. F1 male rats were maintained to generate F2 offspring by mating with untreated female rats. Both the F1 rats after weaning and the F2 offspring were not received any other treatments. Our results showed that male F2 offspring in the BPA group exhibited glucose intolerance and β-cell dysfunction. Decreased expression of Igf2 and associated hypermethylation of Igf2 were observed in islets of male F2 offspring. In addition, similar effects were observed in female F2 animals, but the effects were more pronounced in males. Moreover, abnormal expression and methylation of Igf2 was observed in sperm of adult F1 male rats, indicating that epigenetic modification in germ cells can be partly progressed to the next generation. Overall, our study suggests that BPA exposure during early life can result in generational transmission of glucose intolerance and β-cell dysfunction in the offspring through male germ line, which is associated with hypermethylation of Igf2 in islets. The changes of epigenetics in germ cells may contribute to this generational transmission.

  1. Aberrant methylation of imprinted genes is associated with negative hormone receptor status in invasive breast cancer

    PubMed Central

    Barrow, Timothy M; Barault, Ludovic; Ellsworth, Rachel E; Harris, Holly R; Binder, Alexandra M; Valente, Allyson L; Shriver, Craig D; Michels, Karin B

    2015-01-01

    Epigenetic regulation of imprinted genes enables monoallelic expression according to parental origin, and its disruption is implicated in many cancers and developmental disorders. The expression of hormone receptors is significant in breast cancer as they are indicators of cancer cell growth rate and determine response to endocrine therapies. We investigated the frequency of aberrant events and variation in DNA methylation at nine imprinted sites in invasive breast cancer and examined the association with estrogen and progesterone receptor status. Breast tissue and blood from patients with invasive breast cancer (n=38) and benign breast disease (n=30) were compared to those from healthy individuals (n=36), matched to the cancer patients by age at diagnosis, ethnicity, BMI, menopausal status, and familial history of cancer. DNA methylation and allele-specific expression were analyzed by pyrosequencing. Tumor-specific methylation changes at IGF2 DMR2 were observed in 59% of cancer patients, IGF2 DMR0 in 38%, DIRAS3 DMR in 36%, GRB10 ICR in 23%, PEG3 DMR in 21%, MEST ICR in 19%, H19 ICR in 18%, KvDMR in 8%, and SNRPN/SNURF ICR in 4%. Variation of methylation was significantly greater in breast tissue from cancer patients than healthy individuals and benign breast disease. Aberrant methylation of three or more sites was significantly associated with negative estrogen-alpha (Fisher’s Exact Test, p=0.02) and progesterone-A (p=0.02) receptor status. Aberrant events and increased variation of imprinted gene DNA methylation therefore appear to be frequent in invasive breast cancer and are associated with negative estrogen and progesterone receptor status, without loss of monoallelic expression. PMID:25560175

  2. Evidence for possible involvement of IGF type II receptors (IGF2R) in regulating growth of two concomitant dominant follicles in cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Regulation of multiple ovulations in monotocous species such as cattle is not well understood. Gene expression of the FSH receptor (FSHR) in granulosa (GC), and LH receptor (LHR) and IGF2R in GC and theca (TC) cells, as well as estradiol (E2) and progesterone (P4) levels in follicular fluid (FF) wer...

  3. Differential Gene Expression Reveals Mitochondrial Dysfunction in an Imprinting Center Deletion Mouse Model of Prader-Willi Syndrome

    PubMed Central

    Fan, Weiwei; Coskun, Pinar E.; Nalbandian, Angèle; Knoblach, Susan; Resnick, James L.; Hoffman, Eric; Wallace, Douglas C.; Kimonis, Virginia E.

    2013-01-01

    Prader-Willi syndrome (PWS) is a genetic disorder caused by deficiency of imprinted gene expression from the paternal chromosome 15q11-15q13 and clinically characterized by neonatal hypotonia, short stature, cognitive impairment, hypogonadism, hyperphagia, morbid obesity and diabetes. Previous clinical studies suggest that a defect in energy metabolism may be involved in the pathogenesis of PWS. We focused our attention on the genes associated with energy metabolism and found that there were 95 and 66 mitochondrial genes differentially expressed in PWS muscle and brain, respectively. Assessment of enzyme activities of mitochondrial oxidative phosphorylation (OXPHOS) complexes in the brain, heart, liver and muscle were assessed. We found the enzyme activities of the cardiac mitochondrial complexes II+III were upregulated in the imprinting center deletion (PWS-IC) mice compared to the wild type littermates. These studies suggest that differential gene expression, especially of the mitochondrial genes may contribute to the pathophysiology of PWS. PMID:24127921

  4. Genomic Imprinting and the Expression of Affect in Angelman Syndrome: What's in the Smile?

    ERIC Educational Resources Information Center

    Oliver, Chris; Horsler, Kate; Berg, Katy; Bellamy, Gail; Dick, Katie; Griffiths, Emily

    2007-01-01

    Background: Kinship theory (or the genomic conflict hypothesis) proposes that the phenotypic effects of genomic imprinting arise from conflict between paternally and maternally inherited alleles. A prediction arising for social behaviour from this theory is that imbalance in this conflict resulting from a deletion of a maternally imprinted gene,…

  5. Genomic imprinting and reproduction.

    PubMed

    Swales, A K E; Spears, N

    2005-10-01

    Genomic imprinting is the parent-of-origin specific gene expression which is a vital mechanism through both development and adult life. One of the key elements of the imprinting mechanism is DNA methylation, controlled by DNA methyltransferase enzymes. Germ cells undergo reprogramming to ensure that sex-specific genomic imprinting is initiated, thus allowing normal embryo development to progress after fertilisation. In some cases, errors in genomic imprinting are embryo lethal while in others they lead to developmental disorders and disease. Recent studies have suggested a link between the use of assisted reproductive techniques and an increase in normally rare imprinting disorders. A greater understanding of the mechanisms of genomic imprinting and the factors that influence them are important in assessing the safety of these techniques.

  6. Gene structure, DNA methylation, and imprinted expression of the human SNRPN gene

    SciTech Connect

    Glenn, C.C.; Jong, T.C.; Filbrandt, M.M.

    1996-02-01

    The human SNRPN (small nuclear ribonucleoprotein polypeptide N) gene is one of a gene family that encode proteins involved in pre-mRNA splicing and maps to the smallest deletion region involved in the Prader-Willi syndrome (PWS) within chromosome 15q11-q13. Paternal only expression of SNRPN has previously been demonstrated by use of cell lines from PWS patients (maternal allele only) and Angelman syndrome (AS) patients (paternal allele only). We have characterized two previously unidentified 5{prime} exons of the SNRPN gene and demonstrate that exons -1 and 0 are included in the full-length transcript. This gene is expressed in a wide range of somatic tissues and at high, approximately equal levels in all regions of the brain. Both the first exon of SNRPN (exon -1) and the putative transcription start site are embedded within a CpG island. This CpG island is extensively methylated on the repressed maternal allele and is unmethylated on the expressed paternal allele, in a wide range of fetal and adult somatic cells. This provides a quick and highly reliable diagnostic assay for PWS and AS, which is based on DNA-methylation analysis that has been tested on >100 patients in a variety of tissues. Conversely, several CpG sites {approximately}22 kb downstream of the transcription start site in intron 5 are preferentially methylated on the expressed paternal allele in somatic tissues and male germ cells, whereas these same sites are unmethylated in fetal oocytes. These findings are consistent with a key role for DNA methylation in the imprinted inheritance and subsequent gene expression of the human SNRPN gene. 59 refs., 9 figs., 1 tab.

  7. Structure and functional analysis of the IGF-II/IGF2R interaction

    PubMed Central

    Brown, James; Delaine, Carlie; Zaccheo, Oliver J; Siebold, Christian; Gilbert, Robert J; van Boxel, Gijs; Denley, Adam; Wallace, John C; Hassan, A Bassim; Forbes, Briony E; Jones, E Yvonne

    2008-01-01

    Embryonic development and normal growth require exquisite control of insulin-like growth factors (IGFs). In mammals the extracellular region of the cation-independent mannose-6-phosphate receptor has gained an IGF-II-binding function and is termed type II IGF receptor (IGF2R). IGF2R sequesters IGF-II; imbalances occur in cancers and IGF2R is implicated in tumour suppression. We report crystal structures of IGF2R domains 11–12, 11–12–13–14 and domains 11–12–13/IGF-II complex. A distinctive juxtaposition of these domains provides the IGF-II-binding unit, with domain 11 directly interacting with IGF-II and domain 13 modulating binding site flexibility. Our complex shows that Phe19 and Leu53 of IGF-II lock into a hydrophobic pocket unique to domain 11 of mammalian IGF2Rs. Mutagenesis analyses confirm this IGF-II ‘binding-hotspot', revealing that IGF-binding proteins and IGF2R have converged on the same high-affinity site. PMID:18046459

  8. Differential regulation of genomic imprinting by TET proteins in embryonic stem cells

    PubMed Central

    Liu, Lizhi; Mao, Shi-Qing; Ray, Chelsea; Zhang, Yu; Bell, Fong T.; Ng, Sheau-Fang; Xu, Guo-Liang; Li, Xiajun

    2015-01-01

    TET proteins have been found to play an important role in active demethylation at CpG sites in mammals. There are some reports implicating their functions in removal of DNA methylation imprint at the imprinted regions in the germline. However, it is not well established whether TET proteins can also be involved in demethylation of DNA methylation imprint in embryonic stem (ES) cells. Here we report that loss of TET proteins caused significant increase in DNA methylation at the Igf2-H19 imprinted region in ES cells. We also observed variable increase in DNA methylation at the Peg1 imprinted region in the ES clones devoid of TET proteins, in particular in the differentiated ES cells. By contrast, we did not observe significant increase of DNA methylation imprint at the Peg3, Snrpn and Dlk1-Dio3 imprinted regions in ES cells lacking TET proteins. Interestingly, loss of TET proteins did not result in significant increase of DNA methylation imprint at the Igf2-H19 and Peg1 imprinted regions in the embryoid bodies (EB). Therefore, TET proteins seem to be differentially involved in maintaining DNA methylation imprint at a subset of imprinted regions in ES cells and EBs. PMID:26397890

  9. Fluid shear promotes chondrosarcoma cell invasion by activating matrix metalloproteinase 12 via IGF-2 and VEGF signaling pathways

    PubMed Central

    Wang, P; Chen, S-H; Hung, W-C; Paul, C; Zhu, F; Guan, P-P; Huso, DL; Kontrogianni-Konstantopoulos, A; Konstantopoulos, K

    2015-01-01

    Interstitial fluid flow in and around the tumor tissue is a physiologically relevant mechanical signal that regulates intracellular signaling pathways throughout the tumor. Yet, the effects of interstitial flow and associated fluid shear stress on the tumor cell function have been largely overlooked. Using in vitro bioengineering models in conjunction with molecular cell biology tools, we found that fluid shear (2 dyn/cm2) markedly upregulates matrix metalloproteinase 12 (MMP-12) expression and its activity in human chondrosarcoma cells. MMP-12 expression is induced in human chondrocytes during malignant transformation. However, the signaling pathway regulating MMP-12 expression and its potential role in human chondrosarcoma cell invasion and metastasis have yet to be delineated. We discovered that fluid shear stress induces the synthesis of insulin growth factor-2 (IGF-2) and vascular endothelial growth factor (VEGF) B and D, which in turn transactivate MMP-12 via PI3-K, p38 and JNK signaling pathways. IGF-2-, VEGF-B- or VEGF-D-stimulated chondrosarcoma cells display markedly higher migratory and invasive potentials in vitro, which are blocked by inhibiting MMP-12, PI3-K, p38 or JNK activity. Moreover, recombinant human MMP-12 or MMP-12 overexpression can potentiate chondrosarcoma cell invasion in vitro and the lung colonization in vivo. By reconstructing and delineating the signaling pathway regulating MMP-12 activation, potential therapeutic strategies that interfere with chondrosarcoma cell invasion may be identified. PMID:25435370

  10. [Genomic imprinting and human pathology].

    PubMed

    Polívková, Z

    2005-01-01

    Genomic imprinting is an epigenetic form of regulation of gene expression. Imprinted genes are transcribed from one allele of specific parental origin. Such genes are normally involved in embryonic growth and behavioral development. Deregulation of imprinted genes has been observed in a number of human diseases as gestation trophoblastic disease, Prader-Willi, Angelmann and Beckwith-Wiedemann syndromes and plays significant role in the carcinogenesis. Review of recent knowledge on mechanism and regulation of imprinting is presented in this paper.

  11. H19 Imprinting Control Region Methylation Requires an Imprinted Environment Only in the Male Germ Line ▿

    PubMed Central

    Gebert, Claudia; Kunkel, David; Grinberg, Alexander; Pfeifer, Karl

    2010-01-01

    The 2.4-kb H19 imprinting control region (H19ICR) is required to establish parent-of-origin-specific epigenetic marks and expression patterns at the Igf2/H19 locus. H19ICR activity is regulated by DNA methylation. The ICR is methylated in sperm but not in oocytes, and this paternal chromosome-specific methylation is maintained throughout development. We recently showed that the H19ICR can work as an ICR even when inserted into the normally nonimprinted alpha fetoprotein locus. Paternal but not maternal copies of the ICR become methylated in somatic tissue. However, the ectopic ICR remains unmethylated in sperm. To extend these findings and investigate the mechanisms that lead to methylation of the H19ICR in the male germ line, we characterized novel mouse knock-in lines. Our data confirm that the 2.4-kb element is an autonomously acting ICR whose function is not dependent on germ line methylation. Ectopic ICRs become methylated in the male germ line, but the timing of methylation is influenced by the insertion site and by additional genetic information. Our results support the idea that DNA methylation is not the primary genomic imprint and that the H19ICR insertion is sufficient to transmit parent-of-origin-dependent DNA methylation patterns independent of its methylation status in sperm. PMID:20038532

  12. G Allele of the IGF2 ApaI Polymorphism Is Associated With Judo Status.

    PubMed

    Itaka, Toshio; Agemizu, Kenichiro; Aruga, Seiji; Machida, Shuichi

    2016-07-01

    Itaka, T, Agemizu, K, Aruga, S, and Machida, S. G allele of the IGF2 ApaI polymorphism is associated with judo status. J Strength Cond Res 30(7): 2043-2048, 2016-Previous studies have reported that the insulin-like growth factor 2 (IGF2) ApaI polymorphism is associated with body mass index, fat mass, and grip strength. Competitive judo requires high levels of strength and power. The purpose of this study was to investigate the association between the IGF2 ApaI and ACTN3 R577X polymorphisms and judo status. The subjects were 156 male judo athletes from a top-level university in Japan. They were divided into 3 groups based on their competitive history: international-level athletes, national-level athletes, and others. Genomic DNA was extracted from the saliva of each athlete, and the maximal isometric strength of the trunk muscles and handgrip strength were measured. Genotyping by polymerase chain reaction-restriction fragment length polymorphism was used to detect IGF2 (rs680) and α-actinin-3 (ACTN3) (rs1815739) gene polymorphisms. The genotype frequencies of the 2 gene polymorphisms were compared among the 3 groups of judo athletes and controls. International-level judo athletes showed a higher frequency of the GG + GA genotype of the IGF2 gene than that of the national-level athletes and others. There was an inverse linear correlation between the frequency of the IGF2 AA genotype and level of judo performance (p = 0.041). Back muscle strength relative to height and weight was higher in subjects with the GG + GA genotype than in those with the AA genotype. Conversely, the ACTN3 R577X polymorphism was not associated with judo status. Additionally, no differences were found in back muscle or handgrip strength among the ACTN3 genotypes. In conclusion, the results indicate that the IGF2 gene polymorphism may be associated with judo status.

  13. Dynamic Expression of Imprinted Genes Associates with Maternally Controlled Nutrient Allocation during Maize Endosperm Development[W][OPEN

    PubMed Central

    Xin, Mingming; Yang, Ruolin; Li, Guosheng; Chen, Hao; Laurie, John; Ma, Chuang; Wang, Dongfang; Yao, Yingyin; Larkins, Brian A.; Sun, Qixin; Yadegari, Ramin; Wang, Xiangfeng; Ni, Zhongfu

    2013-01-01

    In angiosperms, the endosperm provides nutrients for embryogenesis and seed germination and is the primary tissue where gene imprinting occurs. To identify the imprintome of early developing maize (Zea mays) endosperm, we performed high-throughput transcriptome sequencing of whole kernels at 0, 3, and 5 d after pollination (DAP) and endosperms at 7, 10, and 15 DAP, using B73 by Mo17 reciprocal crosses. We observed gradually increased expression of paternal transcripts in 3- and 5-DAP kernels. In 7-DAP endosperm, the majority of the genes tested reached a 2:1 maternal versus paternal ratio, suggesting that paternal genes are nearly fully activated by 7 DAP. A total of 116, 234, and 63 genes exhibiting parent-specific expression were identified at 7, 10, and 15 DAP, respectively. The largest proportion of paternally expressed genes was at 7 DAP, mainly due to the significantly deviated parental allele expression ratio of these genes at this stage, while nearly 80% of the maternally expressed genes (MEGs) were specific to 10 DAP and were primarily attributed to sharply increased expression levels compared with the other stages. Gene ontology enrichment analysis of the imprinted genes suggested that 10-DAP endosperm-specific MEGs are involved in nutrient uptake and allocation and the auxin signaling pathway, coincident with the onset of starch and storage protein accumulation. PMID:24058158

  14. Diseases associated with genomic imprinting.

    PubMed

    Wilkins, Jon F; Úbeda, Francisco

    2011-01-01

    Genomic imprinting is the phenomenon where the expression of a locus differs between the maternally and paternally inherited alleles. Typically, this manifests as transcriptional silencing of one of the alleles, although many genes are imprinted in a tissue- or isoform-specific manner. Diseases associated with imprinted genes include various cancers, disorders of growth and metabolism, and disorders in neurodevelopment, cognition, and behavior, including certain major psychiatric disorders. In many cases, the disease phenotypes associated with dysfunction at particular imprinted loci can be understood in terms of the evolutionary processes responsible for the origin of imprinting. Imprinted gene expression represents the outcome of an intragenomic evolutionary conflict, where natural selection favors different expression strategies for maternally and paternally inherited alleles. This conflict is reasonably well understood in the context of the early growth effects of imprinted genes, where paternally inherited alleles are selected to place a greater demand on maternal resources than are maternally inherited alleles. Less well understood are the origins of imprinted gene expression in the brain, and their effects on cognition and behavior. This chapter reviews the genetic diseases that are associated with imprinted genes, framed in terms of the evolutionary pressures acting on gene expression at those loci. We begin by reviewing the phenomenon and evolutionary origins of genomic imprinting. We then discuss diseases that are associated with genetic or epigenetic defects at particular imprinted loci, many of which are associated with abnormalities in growth and/or feeding behaviors that can be understood in terms of the asymmetric pressures of natural selection on maternally and paternally inherited alleles. We next described the evidence for imprinted gene effects on adult cognition and behavior, and the possible role of imprinted genes in the etiology of certain

  15. Imprinting evolution and human health.

    PubMed

    Das, Radhika; Hampton, Daniel D; Jirtle, Randy L

    2009-01-01

    Genomic imprinting results in parent-of-origin-dependent, monoallelic expression of genes. The functional haploid state of these genes has far-reaching consequences. Not only has imprinting been implicated in accelerating mammalian speciation, there is growing evidence that it is also involved in the pathogenesis of several human conditions, particularly cancer and neurological disorders. Epigenetic regulatory mechanisms govern the parental allele-specific silencing of imprinted genes, and many theories have attempted to explain the driving force for the evolution of this unique form of gene control. This review discusses the evolution of imprinting in Therian mammals, and the importance of imprinted genes in human health and disease.

  16. DNA methylation in the IGF2 intragenic DMR is re-established in a sex-specific manner in bovine blastocysts after somatic cloning.

    PubMed

    Gebert, Claudia; Wrenzycki, Christine; Herrmann, Doris; Gröger, Daniela; Thiel, Janina; Reinhardt, Richard; Lehrach, Hans; Hajkova, Petra; Lucas-Hahn, Andrea; Carnwath, Joseph W; Niemann, Heiner

    2009-07-01

    The recent identification of an intragenic differentially methylated region (DMR) within the last exon of the bovine Insulin-like growth factor 2 (IGF2) gene provides a diagnostic tool for in-depth investigation of bovine imprinting and regulatory mechanisms which are active during embryo development. Here, we used bisulfite sequencing to compare sex-specific DNA methylation patterns within this DMR in bovine blastocysts produced in vivo, by in vitro fertilization and culture, SCNT, androgenesis or parthenogenesis. In in vivo derived embryos, DNA methylation was removed from this intragenic DMR after fertilization, but partially replaced by the time the embryo reached the blastocyst stage. Among embryos developing in vivo, the level of DNA methylation was significantly lower in female than in male blastocysts. This sexual dimorphism was also found between parthenogenetic and androgenetic embryos, and followed the donor cell sex in SCNT derived blastocysts and is evidence for correct methylation reprogramming in SCNT embryos.

  17. A Targetable GATA2-IGF2 Axis Confers Aggressiveness in Lethal Prostate Cancer

    PubMed Central

    Vidal, Samuel J.; Rodriguez-Bravo, Veronica; Quinn, S. Aidan; Rodriguez-Barrueco, Ruth; Lujambio, Amaia; Williams, Estrelania; Sun, Xiaochen; de la Iglesia-Vicente, Janis; Lee, Albert; Readhead, Ben; Chen, Xintong; Galsky, Matthew; Esteve, Berta; Petrylak, Daniel P.; Dudley, Joel T.; Rabadan, Raul; Silva, Jose M.; Hoshida, Yujin; Lowe, Scott W.; Cordon-Cardo, Carlos; Domingo-Domenech, Josep

    2015-01-01

    SUMMARY Elucidating the determinants of aggressiveness in lethal prostate cancer may stimulate therapeutic strategies that improve clinical outcomes. We used experimental models and clinical databases to identify GATA2 as a regulator of chemotherapy resistance and tumorigenicity in this context. Mechanistically, direct upregulation of the growth hormone IGF2 emerged as a mediator of the aggressive properties regulated by GATA2. IGF2 in turn activated IGF1R and INSR as well as a downstream polykinase program. The characterization of this axis prompted a combination strategy whereby dual IGF1R/INSR inhibition restored the efficacy of chemotherapy and improved survival in preclinical models. These studies reveal a GATA2-IGF2 aggressiveness axis in lethal prostate cancer and identify a therapeutic opportunity in this challenging disease. PMID:25670080

  18. H19 controls reactivation of the imprinted gene network during muscle regeneration.

    PubMed

    Martinet, Clémence; Monnier, Paul; Louault, Yann; Benard, Matthieu; Gabory, Anne; Dandolo, Luisa

    2016-03-15

    The H19 locus controls fetal growth by regulating expression of several genes from the imprinted gene network (IGN). H19 is fully repressed after birth, except in skeletal muscle. Using loss-of-function H19(Δ3) mice, we investigated the function of H19 in adult muscle. Mutant muscles display hypertrophy and hyperplasia, with increased Igf2 and decreased myostatin (Mstn) expression. Many imprinted genes are expressed in muscle stem cells or satellite cells. Unexpectedly, the number of satellite cells was reduced by 50% in H19(Δ3) muscle fibers. This reduction occurred after postnatal day 21, suggesting a link with their entry into quiescence. We investigated the biological function of these mutant satellite cells in vivo using a regeneration assay induced by multiple injections of cardiotoxin. Surprisingly, despite their reduced number, the self-renewal capacity of these cells is fully retained in the absence of H19. In addition, we observed a better regeneration potential of the mutant muscles, with enhanced expression of several IGN genes and genes from the IGF pathway.

  19. Imprinting on chromosome 20: tissue-specific imprinting and imprinting mutations in the GNAS locus.

    PubMed

    Kelsey, Gavin

    2010-08-15

    The GNAS locus on chromosome 20q13.11 is the archetypal complex imprinted locus. It comprises a bewildering array of alternative transcripts determined by differentially imprinted promoters which encode distinct proteins. It also provides the classic example of tissue-specific imprinted gene expression, in which the canonical GNAS transcript coding for Gsalpha is expressed predominantly from the maternal allele in a set of seemingly unrelated tissues. Functionally, this rather obscure imprinting is nevertheless of considerable clinical significance, as it dictates the nature of the disease caused by inactivating mutations in Gsalpha, with end organ hormone resistance specifically on maternal transmission (pseudohypoparathyroidism type 1a, PHP1a). In addition, there is a bona fide imprinting disorder, PHP1b, which is caused specifically by DNA methylation defects in the differentially methylated regions (DMRs) that determine tissue-specific monoallelic expression of GNAS. Although the genetic defect in PHP1a and the disrupted imprinting in PHP1b both essentially result in profound reduction of Gsalpha activity in tissues with monoallelic GNAS expression, and despite a growing awareness of the overlap in these two conditions, there are important pathophysiological differences between the two whose basis is not fully understood. PHP1b is one of the only imprinted gene syndromes in which cis-acting mutations have been discovered that disrupt methylation of germline-derived imprint marks; such imprinting mutations in GNAS are helping to provide important new insights into the mechanisms of imprinting establishment generally.

  20. Genomic imprinting and environmental disease susceptibility.

    PubMed

    Jirtle, R L; Sander, M; Barrett, J C

    2000-03-01

    Genomic imprinting is one of the most intriguing subtleties of modern genetics. The term "imprinting" refers to parent-of-origin-dependent gene expression. The presence of imprinted genes can cause cells with a full parental complement of functional autosomal genes to specifically express one allele but not the other, resulting in monoallelic expression of the imprinted loci. Genomic imprinting plays a critical role in fetal growth and behavioral development, and it is regulated by DNA methylation and chromatin structure. This paper summarizes the Genomic Imprinting and Environmental Disease Susceptibility Conference held 8-10 October 1998 at Duke University, Durham, North Carolina. The conference focused on the importance of genomic imprinting in determining susceptibility to environmentally induced diseases. Conference topics included rationales for imprinting: parental antagonism and speciation; methods for imprinted gene identification: allelic message display and monochromosomal mouse/human hybrids; properties of the imprinted gene cluster human 11p15.5 and mouse distal 7; the epigenetics of X-chromosome inactivation; variability in imprinting: imprint erasure, non-Mendelian inheritance ratios, and polymorphic imprinting; imprinting and behavior: genetics of bipolar disorder, imprinting in Turner syndrome, and imprinting in brain development and social behavior; and aberrant methylation: methylation and chromatin structure, methylation and estrogen exposure, methylation of tumor-suppressor genes, and cancer susceptibility. Environmental factors are capable of causing epigenetic changes in DNA that can potentially alter imprint gene expression and that can result in genetic diseases including cancer and behavioral disorders. Understanding the contribution of imprinting to the regulation of gene expression will be an important step in evaluating environmental influences on human health and disease.

  1. Imprinted Genes and Satellite Loci Are Differentially Methylated in Bovine Somatic Cell Nuclear Transfer Clones

    PubMed Central

    Shen, Chih-Jie; Lin, Chiao-Chieh; Shen, Perng-Chih; Cheng, Winston T.K.; Chen, Hsiao-Ling; Chang, Tsung-Chou; Liu, Shyh-Shyan

    2013-01-01

    Abstract In mammals, genome-wide epigenetic reprogramming systems exist in primordial germ cells and zygotes. These reprogramming systems play crucial roles in regulating genome functions during critical stages of embryonic development, and they confer the stability of gene expression during mammalian development. The frequent unexpected loss of progeny from somatic cell nuclear transfer (SCNT) is an ongoing problem. In this study, we used six cloned bovines (named NT-1 to NT-6), which were created by ear fibroblast nuclear transfer and displayed short life spans with multiple organ defects, as an experimental model. We focus here on three imprinted genes (IGF2, H19, and XIST) and four satellite loci (Satellite I, Satellite II, Art2, and VNTR) to investigate their methylation changes. The results revealed that aberrant methylation frequently occurred in the analyzed imprinted genes, but not in the satellite loci, of the cloned bovines. After the bovine fibroblast cells were treated with the 5-aza-2(′)-deoxycytidine (5-Aza-dc) demethylation agent, the methylation percentages of the XIST and H19 putative differentially methylated region (DMR) were significantly decreased (XIST, p<0.01; H19, p<0.05) followed by an increase in their mRNA expression levels (p<0.01). Furthermore, we found that five short-lived cloned bovines (NT-1 to NT-5) exhibited more severe aberrant methylation changes in the three imprinted genes examined than the little longer-lived clone (NT-6) compared with wild-type (WT) cows. Our data suggest that the reprogramming of the methylation-controlled regions between the imprinted genes and satellite loci are differences and may be involved with additional mechanisms that need further elucidation. PMID:23961768

  2. Evolution and function of genomic imprinting in plants

    PubMed Central

    Rodrigues, Jessica A.; Zilberman, Daniel

    2015-01-01

    Genomic imprinting, an inherently epigenetic phenomenon defined by parent of origin-dependent gene expression, is observed in mammals and flowering plants. Genome-scale surveys of imprinted expression and the underlying differential epigenetic marks have led to the discovery of hundreds of imprinted plant genes and confirmed DNA and histone methylation as key regulators of plant imprinting. However, the biological roles of the vast majority of imprinted plant genes are unknown, and the evolutionary forces shaping plant imprinting remain rather opaque. Here, we review the mechanisms of plant genomic imprinting and discuss theories of imprinting evolution and biological significance in light of recent findings. PMID:26680300

  3. Evolution and function of genomic imprinting in plants.

    PubMed

    Rodrigues, Jessica A; Zilberman, Daniel

    2015-12-15

    Genomic imprinting, an inherently epigenetic phenomenon defined by parent of origin-dependent gene expression, is observed in mammals and flowering plants. Genome-scale surveys of imprinted expression and the underlying differential epigenetic marks have led to the discovery of hundreds of imprinted plant genes and confirmed DNA and histone methylation as key regulators of plant imprinting. However, the biological roles of the vast majority of imprinted plant genes are unknown, and the evolutionary forces shaping plant imprinting remain rather opaque. Here, we review the mechanisms of plant genomic imprinting and discuss theories of imprinting evolution and biological significance in light of recent findings.

  4. Expression of messenger RNAs for insulin-like growth factors and their receptors in bovine fetuses at early gestation from embryos produced in vivo or in vitro.

    PubMed

    Farin, C E; Alexander, J E; Farin, P W

    2010-10-15

    The objective of this study was to determine the effects of in vitro embryo production on physical development and levels of expression of mRNAs for insulin-like growth factor (IGF) ligands (IGF1, IGF2), their receptors (IGF1R, IGF2R), and IGF binding protein-2 (IGFBP2) in bovine fetuses during early gestation. In vivo embryos were recovered from superovulated Holstein cows. For production of embryos in vitro, Holstein oocytes were matured, fertilized, and subsequently cultured in M199 with 10% serum to 168 hpi. On Day 70 of gestation, fetuses (in vivo, n = 14; in vitro, n = 13) were recovered, serum samples collected, and physical measurements recorded. Semi-quantitative RT-PCR assays were used to determine the levels of expression of mRNAs for IGF1, IGF2, IGF1R, and IGF2R in fetal liver and skeletal muscle. Western blots were used to assess levels of IGFBP2 in fetal serum. Fetal body weight did not differ with treatment; however, production of embryos in vitro was associated with decreased crown-nose length and a tendency for increased paired kidney weight, which became significant when expressed on a per bodyweight basis. There was no effect of treatment on levels of IGFBP2 in fetal serum. Levels of IGF1 mRNA in fetal liver were decreased (P < 0.001) in the in vitro group. Levels of IGF2R mRNA in both liver and skeletal muscle were also decreased (P < 0.01) in fetuses from the in vitro group. In summary, fetuses at Day 70 of gestation from embryos produced in vitro had shortened crown-nose length and increased kidney weight on a per bodyweight basis, as well as decreased expression of mRNAs for IGF1 in liver and IGF2R in both liver and skeletal muscle, compared with fetuses from embryos produced in vivo. In conclusion, in vitro embryo culture was associated with subtle changes in fetal development as well as altered expression of both imprinted and non-imprinted genes.

  5. Epigenetics and imprinting in human disease.

    PubMed

    Kalish, Jennifer M; Jiang, Connie; Bartolomei, Marisa S

    2014-01-01

    Most genes are expressed from both parental chromosomes; however, a small number of genes in mammals are imprinted and expressed in a parent-of-origin specific manner. These imprinted genes play an important role in embryonic and extraembryonic growth and development, as well as in a variety of processes after birth. Many imprinted genes are clustered in the genome with the establishment and maintenance of imprinted gene expression governed by complex epigenetic mechanisms. Dysregulation of these epigenetic mechanisms as well as genomic mutations at imprinted gene clusters can lead to human disease.

  6. Metabolic hormones regulate basal and growth hormone-dependent igf2 mRNA level in primary cultured coho salmon hepatocytes: effects of insulin, glucagon, dexamethasone, and triiodothyronine.

    PubMed

    Pierce, A L; Dickey, J T; Felli, L; Swanson, P; Dickhoff, W W

    2010-03-01

    Igf1 and Igf2 stimulate growth and development of vertebrates. Circulating Igfs are produced by the liver. In mammals, Igf1 mediates the postnatal growth-promoting effects of growth hormone (Gh), whereas Igf2 stimulates fetal and placental growth. Hepatic Igf2 production is not regulated by Gh in mammals. Little is known about the regulation of hepatic Igf2 production in nonmammalian vertebrates. We examined the regulation of igf2 mRNA level by metabolic hormones in primary cultured coho salmon hepatocytes. Gh, insulin, the glucocorticoid agonist dexamethasone (Dex), and glucagon increased igf2 mRNA levels, whereas triiodothyronine (T(3)) decreased igf2 mRNA levels. Gh stimulated igf2 mRNA at physiological concentrations (0.25x10(-9) M and above). Insulin strongly enhanced Gh stimulation of igf2 at low physiological concentrations (10(-11) M and above), and increased basal igf2 (10(-8) M and above). Dex stimulated basal igf2 at concentrations comparable to those of stressed circulating cortisol (10(-8) M and above). Glucagon stimulated basal and Gh-stimulated igf2 at supraphysiological concentrations (10(-7) M and above), whereas T(3) suppressed basal and Gh-stimulated igf2 at the single concentration tested (10(-7) M). These results show that igf2 mRNA level is highly regulated in salmon hepatocytes, suggesting that liver-derived Igf2 plays a significant role in salmon growth physiology. The synergistic regulation of igf2 by insulin and Gh in salmon hepatocytes is similar to the regulation of hepatic Igf1 production in mammals.

  7. Genomic imprinting and human disease.

    PubMed

    Hirasawa, Ryutaro; Feil, Robert

    2010-09-20

    In many epigenetic phenomena, covalent modifications on DNA and chromatin mediate somatically heritable patterns of gene expression. Genomic imprinting is a classical example of epigenetic regulation in mammals. To date, more than 100 imprinted genes have been identified in humans and mice. Many of these are involved in foetal growth and deve lopment, others control behaviour. Mono-allelic expression of imprinted genes depends on whether the gene is inherited from the mother or the father. This remarkable pattern of expression is controlled by specialized sequence elements called ICRs (imprinting control regions). ICRs are marked by DNA methylation on one of the two parental alleles. These allelic marks originate from either the maternal or the paternal germ line. Perturbation of the allelic DNA methylation at ICRs is causally involved in several human diseases, including the Beckwith-Wiedemann and Silver-Russell syndromes, associated with aberrant foetal growth. Perturbed imprinted gene expression is also implicated in the neuro-developmental disorders Prader-Willi syndrome and Angelman syndrome. Embryo culture and human-assisted reproduction procedures can increase the occurrence of imprinting-related disorders. Recent research shows that, besides DNA methylation, covalent histone modifications and non-histone proteins also contribute to imprinting regulation. The involvement of imprinting in specific human pathologies (and in cancer) emphasizes the need to further explore the underlying molecular mechanisms.

  8. Growth regulation, imprinting, and epigenetic transcription-related gene expression differs in lung of deceased transgenic cloned and normal goats.

    PubMed

    Meng, Li; Jia, Ruo-Xin; Sun, Yan-Yan; Wang, Zi-Yu; Wan, Yong-Jie; Zhang, Yan-Li; Zhong, Bu-Shuai; Wang, Feng

    2014-02-01

    Somatic cell nuclear transfer (SCNT) is a promising technique to produce mammalian transgenic clones. Only a small proportion of manipulated embryos, however, can develop into viable offspring. The abnormal growth and development of cloned animals, furthermore, are accompanied by aberrant lung development. Our objective was to investigate molecular background of lung developmental problems in transgenic (random insertion of exogenous DNA) cloned goats. We examined expression of 15 genes involved in growth regulation, imprinting, and epigenetic transcription in lung tissue of deceased transgenic cloned and normal goats of various ages. Compared with normal goats of the same age from conventional reproduction, expression of 13 genes (BMP4, FGF10, GHR, HGFR, PDGFR, RABP, VEGF, H19, CDKNIC, PCAF, MeCP2, HDAC1, and Dnmt3b) decreased in transgenic cloned goats that died at or shortly after birth; Expression of eight genes (FGF10, PDGFR, RABP, VEGF, PCAF, HDAC1, MeCP2, and Dnmt3b) decreased in fetal death of transgenic cloned goats. Expression of two epigenetic transcription genes (PCAF and Dnmt3b) decreased in disease death of transgenic cloned goats (1-4 months old). Disruptions in gene expression might be associated with the high neonatal mortality in transgenic cloned animals. These findings have implications in understanding the low efficiency of transgenic cloning.

  9. MiR-216b is involved in pathogenesis and progression of hepatocellular carcinoma through HBx-miR-216b-IGF2BP2 signaling pathway

    PubMed Central

    Liu, F-y; Zhou, S-j; Deng, Y-l; Zhang, Z-y; Zhang, E-l; Wu, Z-b; Huang, Z-y; Chen, X-p

    2015-01-01

    This study aims to investigate the expression status of miRNA-216b in familial hepatocellular carcinoma (HCC) and the correlation between miRNA-216b expression and pathogenesis, as well as the progression of HCC. The expression profile of miRNAs in plasma of peripheral blood between HCC patients with HCC family history and healthy volunteers without HCC family history was determined by microarray. Using real-time quantitative PCR to detect the expression in paired tissues from 150 patients with HCC, miR-216b was selected as its expression value in HCC patients was significantly lower compared with healthy volunteers. Next, miR-216b expression and the clinicopathological features of HCC were evaluated. The effect of miR-216b expression on tumor cells was investigated by regulating miR-216b expression in SMMC-7721 and HepG2 in vitro and in vivo. Finally, we explored mRNA targets of miR-216b. In 150 HCC, 37 (75%) tumors showed reduced miR-216b expression comparing with their adjacent liver tissues. The decreased expression of miR-216b was significantly correlated with tumor volume (P=0.044), HBV infection (P=0.026), HBV DNA quantitative (P=0.001) and vascular invasion (P=0.032). The 5-year disease-free survival and overall rates after liver resection in low expression and high expression groups of miR-216b are 62% and 54%, 25% and 20%, respectively. MiR-216b overexpression inhibited cell proliferation, migration and invasion, and miR-216b inhibition did the opposite. The expression of hepatitis B virus x protein (HBx) has tight correlation with downregulation of miR-216b. Furthermore, miR-216b downregulated the expression of insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) and exerted its tumor-suppressor function through inhibition of protein kinase B and extracellular signal-regulated kinase signaling downstream of IGF2. MiR-216b inhibits cell proliferation, migration and invasion of HCC by regulating IGF2BP2 and it is regulated by HBx. PMID:25741595

  10. Birth weight, working memory and epigenetic signatures in IGF2 and related genes: a MZ twin study.

    PubMed

    Córdova-Palomera, Aldo; Alemany, Silvia; Fatjó-Vilas, Mar; Goldberg, Ximena; Leza, Juan Carlos; González-Pinto, Ana; Nenadic, Igor; Fañanás, Lourdes

    2014-01-01

    Neurodevelopmental disruptions caused by obstetric complications play a role in the etiology of several phenotypes associated with neuropsychiatric diseases and cognitive dysfunctions. Importantly, it has been noticed that epigenetic processes occurring early in life may mediate these associations. Here, DNA methylation signatures at IGF2 (insulin-like growth factor 2) and IGF2BP1-3 (IGF2-binding proteins 1-3) were examined in a sample consisting of 34 adult monozygotic (MZ) twins informative for obstetric complications and cognitive performance. Multivariate linear regression analysis of twin data was implemented to test for associations between methylation levels and both birth weight (BW) and adult working memory (WM) performance. Familial and unique environmental factors underlying these potential relationships were evaluated. A link was detected between DNA methylation levels of two CpG sites in the IGF2BP1 gene and both BW and adult WM performance. The BW-IGF2BP1 methylation association seemed due to non-shared environmental factors influencing BW, whereas the WM-IGF2BP1 methylation relationship seemed mediated by both genes and environment. Our data is in agreement with previous evidence indicating that DNA methylation status may be related to prenatal stress and later neurocognitive phenotypes. While former reports independently detected associations between DNA methylation and either BW or WM, current results suggest that these relationships are not confounded by each other.

  11. Birth Weight, Working Memory and Epigenetic Signatures in IGF2 and Related Genes: A MZ Twin Study

    PubMed Central

    Córdova-Palomera, Aldo; Alemany, Silvia; Fatjó-Vilas, Mar; Goldberg, Ximena; Leza, Juan Carlos; González-Pinto, Ana; Nenadic, Igor; Fañanás, Lourdes

    2014-01-01

    Neurodevelopmental disruptions caused by obstetric complications play a role in the etiology of several phenotypes associated with neuropsychiatric diseases and cognitive dysfunctions. Importantly, it has been noticed that epigenetic processes occurring early in life may mediate these associations. Here, DNA methylation signatures at IGF2 (insulin-like growth factor 2) and IGF2BP1-3 (IGF2-binding proteins 1-3) were examined in a sample consisting of 34 adult monozygotic (MZ) twins informative for obstetric complications and cognitive performance. Multivariate linear regression analysis of twin data was implemented to test for associations between methylation levels and both birth weight (BW) and adult working memory (WM) performance. Familial and unique environmental factors underlying these potential relationships were evaluated. A link was detected between DNA methylation levels of two CpG sites in the IGF2BP1 gene and both BW and adult WM performance. The BW-IGF2BP1 methylation association seemed due to non-shared environmental factors influencing BW, whereas the WM-IGF2BP1 methylation relationship seemed mediated by both genes and environment. Our data is in agreement with previous evidence indicating that DNA methylation status may be related to prenatal stress and later neurocognitive phenotypes. While former reports independently detected associations between DNA methylation and either BW or WM, current results suggest that these relationships are not confounded by each other. PMID:25171170

  12. Genomic matrix attachment region and chromosome conformation capture quantitative real time PCR assays identify novel putative regulatory elements at the imprinted Dlk1/Gtl2 locus.

    PubMed

    Braem, Caroline; Recolin, Bénédicte; Rancourt, Rebecca C; Angiolini, Christopher; Barthès, Pauline; Branchu, Priscillia; Court, Franck; Cathala, Guy; Ferguson-Smith, Anne C; Forné, Thierry

    2008-07-04

    We previously showed that genomic imprinting regulates matrix attachment region activities at the mouse Igf2 (insulin-like growth factor 2) locus and that these activities are functionally linked to neighboring differentially methylated regions (DMRs). Here, we investigate the similarly structured Dlk1/Gtl2 imprinted domain and show that in the mouse liver, the G/C-rich intergenic germ line-derived DMR, a sequence involved in domain-wide imprinting, is highly retained within the nuclear matrix fraction exclusively on the methylated paternal copy, reflecting its differential function on that chromosome. Therefore, not only "classical" A/T-rich matrix attachment region (MAR) sequences but also other important regulatory DNA elements (such as DMRs) can be recovered from genomic MAR assays following a high salt treatment. Interestingly, the recovery of one A/T-rich sequence (MAR4) from the "nuclear matrix" fraction is strongly correlated with gene expression. We show that this element possesses an intrinsic activity that favors transcription, and using chromosome conformation capture quantitative real time PCR assays, we demonstrate that the MAR4 interacts with the intergenic germ line-derived DMR specifically on the paternal allele but not with the Dlk1/Gtl2 promoters. Altogether, our findings shed a new light on gene regulation at this locus.

  13. Genomic imprinting and dermatological disease.

    PubMed

    Millington, G W M

    2006-09-01

    Imprinting is the process whereby genetic alleles responsible for a phenotype are derived from one parent only. It is an epigenetic phenomenon resulting from DNA methylation or modification of protruding histones. When imprinted genes are disrupted, syndromes with characteristic patterns of inheritance and multisystem phenotype occur. Those detailed in this article have some quite characteristic cutaneous features and patterns of inheritance. These diseases include Beckwith-Wiedmann, Silver-Russell, Prader-Willi, McCune-Albright and Angelman syndromes, Albright's hereditary osteodystrophy, and progressive osseous heteroplasia. In the case of Von Hippel-Lindau syndrome, hypomelanosis of Ito and dermatopathia pigmentosa reticularis, imprinting may play a part in the inheritance. With neurofibromatosis type 1, a nonimprinted condition, the expression of the phenotype could be affected by interaction with imprinted gene loci. Imprinted genes could also play a part in the polygenetic inheritance of more common diseases also, as atopic eczema and psoriasis may have predominantly maternal and paternal modes of transmission, respectively.

  14. Antagonist Xist and Tsix co-transcription during mouse oogenesis and maternal Xist expression during pre-implantation development calls into question the nature of the maternal imprint on the X chromosome.

    PubMed

    Deuve, Jane Lynda; Bonnet-Garnier, Amélie; Beaujean, Nathalie; Avner, Philip; Morey, Céline

    2015-01-01

    During the first divisions of the female mouse embryo, the paternal X-chromosome is coated by Xist non-coding RNA and gradually silenced. This imprinted X-inactivation principally results from the apposition, during oocyte growth, of an imprint on the X-inactivation master control region: the X-inactivation center (Xic). This maternal imprint of yet unknown nature is thought to prevent Xist upregulation from the maternal X (X(M)) during early female development. In order to provide further insight into the X(M) imprinting mechanism, we applied single-cell approaches to oocytes and pre-implantation embryos at different stages of development to analyze the expression of candidate genes within the Xic. We show that, unlike the situation pertaining in most other cellular contexts, in early-growing oocytes, Xist and Tsix sense and antisense transcription occur simultaneously from the same chromosome. Additionally, during early development, Xist appears to be transiently transcribed from the X(M) in some blastomeres of late 2-cell embryos concomitant with the general activation of the genome indicating that X(M) imprinting does not completely suppress maternal Xist transcription during embryo cleavage stages. These unexpected transcriptional regulations of the Xist locus call for a re-evaluation of the early functioning of the maternal imprint on the X-chromosome and suggest that Xist/Tsix antagonist transcriptional activities may participate in imprinting the maternal locus as described at other loci subject to parental imprinting.

  15. mRNA levels of imprinted genes in bovine in vivo oocytes, embryos and cross species comparisons in humans, mice and pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Twenty-six confirmed imprinted genes in the bovine were quantified in in vivo produced oocytes and embryos. Eighteen were detectable and their transcriptional abundance were categorized into five patterns: largely decreased (MEST and PLAGL1); first decreased and then increased (CDKN1C and IGF2R); p...

  16. Comprehensive analysis of imprinted genes in maize reveals allelic variation for imprinting and limited conservation with other species.

    PubMed

    Waters, Amanda J; Bilinski, Paul; Eichten, Steven R; Vaughn, Matthew W; Ross-Ibarra, Jeffrey; Gehring, Mary; Springer, Nathan M

    2013-11-26

    In plants, a subset of genes exhibit imprinting in endosperm tissue such that expression is primarily from the maternal or paternal allele. Imprinting may arise as a consequence of mechanisms for silencing of transposons during reproduction, and in some cases imprinted expression of particular genes may provide a selective advantage such that it is conserved across species. Separate mechanisms for the origin of imprinted expression patterns and maintenance of these patterns may result in substantial variation in the targets of imprinting in different species. Here we present deep sequencing of RNAs isolated from reciprocal crosses of four diverse maize genotypes, providing a comprehensive analysis that allows evaluation of imprinting at more than 95% of endosperm-expressed genes. We find that over 500 genes exhibit statistically significant parent-of-origin effects in maize endosperm tissue, but focused our analyses on a subset of these genes that had >90% expression from the maternal allele (69 genes) or from the paternal allele (108 genes) in at least one reciprocal cross. Over 10% of imprinted genes show evidence of allelic variation for imprinting. A comparison of imprinting in maize and rice reveals that 13% of genes with syntenic orthologs in both species exhibit conserved imprinting. Genes that exhibit conserved imprinting between maize and rice have elevated nonsynonymous to synonymous substitution ratios compared with other imprinted genes, suggesting a history of more rapid evolution. Together, these data suggest that imprinting only has functional relevance at a subset of loci that currently exhibit imprinting in maize.

  17. A novel mutation in the maternally imprinted PEG3 domain results in a loss of MIMT1 expression and causes abortions and stillbirths in cattle (Bos taurus).

    PubMed

    Flisikowski, Krzysztof; Venhoranta, Heli; Nowacka-Woszuk, Joanna; McKay, Stephanie D; Flyckt, Antti; Taponen, Juhani; Schnabel, Robert; Schwarzenbacher, Hermann; Szczerbal, Izabela; Lohi, Hannes; Fries, Ruedi; Taylor, Jeremy F; Switonski, Marek; Andersson, Magnus

    2010-11-30

    Congenital malformations resulting in late abortions and stillbirths affect the economic wellbeing of producers and the welfare of cattle in breeding programs. An extremely high incidence of stillbirths of "half-sized" calves of normal karyotype and uninflated lungs was diagnosed in the progeny of the Finnish Ayrshire (Bos taurus) bull--YN51. No other visible anatomical abnormalities were apparent in the stillborn calves. We herein describe the positional identification of a 110 kb microdeletion in the maternally imprinted PEG3 domain that results in a loss of paternal MIMT1 expression and causes late term abortion and stillbirth in cattle. Using the BovineSNP50 BeadChip we performed a genome-wide half-sib linkage analysis that identified a 13.3 Mb associated region on BTA18 containing the maternally imprinted PEG3 domain. Within this cluster we found a 110 kb microdeletion that removes a part of the non-protein coding MER1 repeat containing imprinted transcript 1 gene (MIMT1). To confirm the elimination of gene expression in calves inheriting this deletion, we examined the mRNA levels of the three maternally imprinted genes within the PEG3 domain, in brain and cotyledon tissue collected from eight fetuses sired by the proband. None of the fetuses that inherited the microdeletion expressed MIMT1 in either tissue. The mutation, when inherited from the sire, is semi-lethal for his progeny with an observed mortality rate of 85%. The survival of 15% is presumably due to the incomplete silencing of maternally inherited MIMT1 alleles. We designed a PCR-based assay to confirm the existence of the microdeletion in the MIMT1 region that can be used to assist cattle breeders in preventing the stillbirths.

  18. Expression patterns of long noncoding RNAs from Dlk1-Dio3 imprinted region and the potential mechanisms of Gtl2 activation during blastocyst development.

    PubMed

    Han, Zhengbin; Yu, Changwei; Tian, Yijun; Zeng, Tiebo; Cui, Wei; Mager, Jesse; Wu, Qiong

    2015-07-31

    The function of long noncoding RNAs (lncRNAs) in cell differentiation and development have begun to be revealed in recent years. However, the expression pattern and mechanisms regulating lncRNAs are largely unknown during mammalian preimplantation development. LncRNAs expressed from Dlk1-Dio3 imprinted region have been linked to pluripotency of induced pluripotent cells (iPSCs). In this study we show that these lncRNAs (Gtl2, Rian and Mirg) are first expressed at the morula stage and gradually restricted to the inner cell mass (ICM) as the embryo differentiates into the blastocyst. Analysis of DNA methylation at IG-DMR and Gtl2-DMR showed no change during preimplantation while the presence of the activating histone modification H3K4me3 increased significantly from 8-cell to blastocyst stage, which may explain the expression activation. Additionally, knockdown of transcription factors (Oct4, Sox2 and Nanog) in blastocyst reduced the expression of Gtl2, indicating pluripotency factors regulate transcription of these lncRNAs. This study provides the spatiotemporal expression and dynamic changes of lncRNAs from Dlk1-Dio3 imprinted region in mouse preimplantation stage embryos and offers insight into the potential mechanisms responsible for Gtl2 activation.

  19. Trichostatin A affects histone acetylation and gene expression in porcine somatic cell nucleus transfer embryos.

    PubMed

    Cervera, R P; Martí-Gutiérrez, N; Escorihuela, E; Moreno, R; Stojkovic, M

    2009-11-01

    Epigenetic aberrancies likely preclude correct and complete nuclear reprogramming after somatic cell nucleus transfer (SCNT) and may underlie the observed reduced viability of cloned embryos. In the current study, we tested the effects of the histone deacetylase-inhibitor trichostatin A (TSA) on preimplantation development and on histone acetylation and the gene expression of nucleus transfer (NT) porcine (Sus scrofa) embryos. Our results showed that 5 nM TSA for 26 h after reconstitution resulted in embryos (NTTSA) that reached the blastocyst stage at a higher level (48.1% vs. 20.2%) and increased number of cells (105.0 vs. 75.3) than that of the control (NTC) embryos. In addition, and unlike the NTC embryos, the treated embryos displayed a global acetylated histone H4 at lysine 8 profile similar to the in vitro-fertilized (IVF) and cultured embryos during the preimplantation development. Finally, we determined that several transcription factors exert a dramatic amount of genetic control over pluripotency, including Oct4, Nanog, Cdx2, and Rex01, the imprinting genes Igf2 and Igf2r, and the histone deacetyltransferase gene Hdac2. The NT blastocysts showed similar levels of Oct4, Cdx2, and Hdac2 but lower levels of Nanog than those of the IVF blastocyst. However, the NTTSA blastocysts showed similar levels of Rex01, Igf2, and Igf2r as those of IVF blastocysts, whereas the NTC blastocysts showed significantly lower levels for those genes. Our results suggest that TSA improves porcine SCNT preimplantation development and affects the acetylated status of the H4K8, rendering acetylation levels similar to those of the IVF counterparts.

  20. Linking Hematopoietic Differentiation to Co-Expressed Sets of Pluripotency-Associated and Imprinted Genes and to Regulatory microRNA-Transcription Factor Motifs

    PubMed Central

    Hamed, Mohamed; Trumm, Johannes; Spaniol, Christian; Sethi, Riccha; Irhimeh, Mohammad R.; Fuellen, Georg; Paulsen, Martina

    2017-01-01

    Maintenance of cell pluripotency, differentiation, and reprogramming are regulated by complex gene regulatory networks (GRNs) including monoallelically-expressed imprinted genes. Besides transcriptional control, epigenetic modifications and microRNAs contribute to cellular differentiation. As a model system for studying the capacity of cells to preserve their pluripotency state and the onset of differentiation and subsequent specialization, murine hematopoiesis was used and compared to embryonic stem cells (ESCs) as a control. Using published microarray data, the expression profiles of two sets of genes, pluripotent and imprinted, were compared to a third set of known hematopoietic genes. We found that more than half of the pluripotent and imprinted genes are clearly upregulated in ESCs but subsequently repressed during hematopoiesis. The remaining genes were either upregulated in hematopoietic progenitors or in differentiated blood cells. The three gene sets each consist of three similarly behaving gene groups with similar expression profiles in various lineages of the hematopoietic system as well as in ESCs. To explain this co-regulation behavior, we explored the transcriptional and post-transcriptional mechanisms of pluripotent and imprinted genes and their regulator/target miRNAs in six different hematopoietic lineages. Therewith, lineage-specific transcription factor (TF)-miRNA regulatory networks were generated and their topologies and functional impacts during hematopoiesis were analyzed. This led to the identification of TF-miRNA co-regulatory motifs, for which we validated the contribution to the cellular development of the corresponding lineage in terms of statistical significance and relevance to biological evidence. This analysis also identified key miRNAs and TFs/genes that might play important roles in the derived lineage networks. These molecular associations suggest new aspects of the cellular regulation of the onset of cellular differentiation and

  1. Olfactory imprinting is correlated with changes in gene expression in the olfactory epithelia of the zebrafish.

    PubMed

    Harden, Maegan V; Newton, Lucy A; Lloyd, Russell C; Whitlock, Kathleen E

    2006-11-01

    Odors experienced as juveniles can have significant effects on the behavior of mature organisms. A dramatic example of this occurs in salmon, where the odors experienced by developing fish determine the river to which they return as adults. Further examples of olfactory memories are found in many animals including vertebrates and invertebrates. Yet, the cellular and molecular bases underlying the formation of olfactory memory are poorly understood. We have devised a series of experiments to determine whether zebrafish can form olfactory memories much like those observed in salmonids. Here we show for the first time that zebrafish form and retain olfactory memories of an artificial odorant, phenylethyl alcohol (PEA), experienced as juveniles. Furthermore, we demonstrate that exposure to PEA results in changes in gene expression within the olfactory sensory system. These changes are evident by in situ hybridization in the olfactory epithelium of the developing zebrafish. Strikingly, our analysis by in situ hybridization demonstrates that the transcription factor, otx2, is up regulated in the olfactory sensory epithelia in response to PEA. This increase is evident at 2-3 days postfertilization and is maintained in the adult animals. We propose that the changes in otx2 gene expression are manifest as an increase in the number of neuronal precursors in the cells olfactory epithelium of the odor-exposed fish. Thus, our results reveal a role for the environment in controlling gene expression in the developing peripheral nervous system.

  2. Transcriptomic imprints of adaptation to fresh water: parallel evolution of osmoregulatory gene expression in the Alewife.

    PubMed

    Velotta, Jonathan P; Wegrzyn, Jill L; Ginzburg, Samuel; Kang, Lin; Czesny, Sergiusz; O'Neill, Rachel J; McCormick, Stephen D; Michalak, Pawel; Schultz, Eric T

    2017-02-01

    Comparative approaches in physiological genomics offer an opportunity to understand the functional importance of genes involved in niche exploitation. We used populations of Alewife (Alosa pseudoharengus) to explore the transcriptional mechanisms that underlie adaptation to fresh water. Ancestrally anadromous Alewives have recently formed multiple, independently derived, landlocked populations, which exhibit reduced tolerance of saltwater and enhanced tolerance of fresh water. Using RNA-seq, we compared transcriptional responses of an anadromous Alewife population to two landlocked populations after acclimation to fresh (0 ppt) and saltwater (35 ppt). Our results suggest that the gill transcriptome has evolved in primarily discordant ways between independent landlocked populations and their anadromous ancestor. By contrast, evolved shifts in the transcription of a small suite of well-characterized osmoregulatory genes exhibited a strong degree of parallelism. In particular, transcription of genes that regulate gill ion exchange has diverged in accordance with functional predictions: freshwater ion-uptake genes (most notably, the 'freshwater paralog' of Na(+) /K(+) -ATPase α-subunit) were more highly expressed in landlocked forms, whereas genes that regulate saltwater ion secretion (e.g. the 'saltwater paralog' of NKAα) exhibited a blunted response to saltwater. Parallel divergence of ion transport gene expression is associated with shifts in salinity tolerance limits among landlocked forms, suggesting that changes to the gill's transcriptional response to salinity facilitate freshwater adaptation.

  3. Intranasal siRNA administration reveals IGF2 deficiency contributes to impaired cognition in Fragile X syndrome mice

    PubMed Central

    Pardo, Marta; Cheng, Yuyan; Velmeshev, Dmitry; Magistri, Marco; Martinez, Ana; Faghihi, Mohammad A.; Jope, Richard S.; Beurel, Eleonore

    2017-01-01

    Molecular mechanisms underlying learning and memory remain imprecisely understood, and restorative interventions are lacking. We report that intranasal administration of siRNAs can be used to identify targets important in cognitive processes and to improve genetically impaired learning and memory. In mice modeling the intellectual deficiency of Fragile X syndrome, intranasally administered siRNA targeting glycogen synthase kinase-3β (GSK3β), histone deacetylase-1 (HDAC1), HDAC2, or HDAC3 diminished cognitive impairments. In WT mice, intranasally administered brain-derived neurotrophic factor (BDNF) siRNA or HDAC4 siRNA impaired learning and memory, which was partially due to reduced insulin-like growth factor-2 (IGF2) levels because the BDNF siRNA– or HDAC4 siRNA–induced cognitive impairments were ameliorated by intranasal IGF2 administration. In Fmr1–/– mice, hippocampal IGF2 was deficient, and learning and memory impairments were ameliorated by IGF2 intranasal administration. Therefore intranasal siRNA administration is an effective means to identify mechanisms regulating cognition and to modulate therapeutic targets. PMID:28352664

  4. Cancer cell-secreted IGF2 instigates fibroblasts and bone marrow-derived vascular progenitor cells to promote cancer progression

    PubMed Central

    Xu, Wen Wen; Li, Bin; Guan, Xin Yuan; Chung, Sookja K.; Wang, Yang; Yip, Yim Ling; Law, Simon Y. K.; Chan, Kin Tak; Lee, Nikki P. Y.; Chan, Kwok Wah; Xu, Li Yan; Li, En Min; Tsao, Sai Wah; He, Qing-Yu; Cheung, Annie L. M.

    2017-01-01

    Local interactions between cancer cells and stroma can produce systemic effects on distant organs to govern cancer progression. Here we show that IGF2 secreted by inhibitor of differentiation (Id1)-overexpressing oesophageal cancer cells instigates VEGFR1-positive bone marrow cells in the tumour macroenvironment to form pre-metastatic niches at distant sites by increasing VEGF secretion from cancer-associated fibroblasts. Cancer cells are then attracted to the metastatic site via the CXCL5/CXCR2 axis. Bone marrow cells transplanted from nude mice bearing Id1-overexpressing oesophageal tumours enhance tumour growth and metastasis in recipient mice, whereas systemic administration of VEGFR1 antibody abrogates these effects. Mechanistically, IGF2 regulates VEGF in fibroblasts via miR-29c in a p53-dependent manner. Analysis of patient serum samples showed that concurrent elevation of IGF2 and VEGF levels may serve as a prognostic biomarker for oesophageal cancer. These findings suggest that the Id1/IGF2/VEGF/VEGFR1 cascade plays a critical role in tumour-driven pathophysiological processes underlying cancer progression. PMID:28186102

  5. Genomic imprinting: parental influence on the genome.

    PubMed

    Reik, W; Walter, J

    2001-01-01

    Genomic imprinting affects several dozen mammalian genes and results in the expression of those genes from only one of the two parental chromosomes. This is brought about by epigenetic instructions--imprints--that are laid down in the parental germ cells. Imprinting is a particularly important genetic mechanism in mammals, and is thought to influence the transfer of nutrients to the fetus and the newborn from the mother. Consistent with this view is the fact that imprinted genes tend to affect growth in the womb and behaviour after birth. Aberrant imprinting disturbs development and is the cause of various disease syndromes. The study of imprinting also provides new insights into epigenetic gene modification during development.

  6. Competition--a common motif for the imprinting mechanism?

    PubMed Central

    Barlow, D P

    1997-01-01

    Imprinted genes, in contrast to the majority of mammalian genes, are able to restrict expression to one of the two parental alleles in somatic diploid cells. Although the silent allele of an imprinted gene appears to be transcriptionally repressed, it often bears little other resemblance to normal genes in an inactive state. The key to the imprinting mechanism may be a form of parental-specific expression-competition between cis-linked genes and not parental-specific expression versus repression. Thus, the imprinting mechanism may be better understood if the chromosomal region containing imprinted genes is viewed as 'active' on both parental chromosomes. PMID:9384569

  7. Genomic imprinting in development, growth, behavior and stem cells.

    PubMed

    Plasschaert, Robert N; Bartolomei, Marisa S

    2014-05-01

    Genes that are subject to genomic imprinting in mammals are preferentially expressed from a single parental allele. This imprinted expression of a small number of genes is crucial for normal development, as these genes often directly regulate fetal growth. Recent work has also demonstrated intricate roles for imprinted genes in the brain, with important consequences on behavior and neuronal function. Finally, new studies have revealed the importance of proper expression of specific imprinted genes in induced pluripotent stem cells and in adult stem cells. As we review here, these findings highlight the complex nature and developmental importance of imprinted genes.

  8. Possible role of IGF2 receptors in regulating selection of 2 dominant follicles in cattle selected for twin ovulations and births

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Abundance of IGF-2 receptor (IGF2R), FSH receptor (FSHR), and LH receptor (LHCGR) mRNA in granulosa cells (GCs) or theca cells (TCs) or both cells as well as estradiol (E2), progesterone (P4), and androstenedione concentrations in follicular fluid were compared in cows genetically selected (Twinner)...

  9. Global demethylation in loss of imprinting subtype of Wilms tumor.

    PubMed

    Ludgate, Jackie L; Le Mée, Gwenn; Fukuzawa, Ryuji; Rodger, Euan J; Weeks, Robert J; Reeve, Anthony E; Morison, Ian M

    2013-02-01

    Epigenetic abnormalities at the IGF2/H19 locus play a key role in the onset of Wilms tumor. These tumors can be classified into three molecular subtypes depending on the events occurring at this locus: loss of imprinting (LOI), loss of heterozygosity (LOH), or retention of imprinting (ROI). As IGF2 LOI is a consequence of aberrant methylation, we hypothesized that this subtype of Wilms tumors might display global abnormalities of methylation. We therefore analyzed the methylation status of satellite DNA, as a surrogate for global methylation in 50 Wilms tumor patients. Satellite methylation was quantified by a methylation-sensitive quantitative PCR. We confirmed hypomethylation of both satellite α (Sat α) and satellite 2 (Sat 2) DNA in Wilms tumor samples compared with normal kidney. In addition, we found that LOI tumors, unlike ROI or LOH ones, showed concordant hypomethylation of both Sat α and Sat 2 DNA. This would suggest that the LOI subtype of Wilms tumor, which unlike other subtypes results from an epimutation, has a global deregulation of methylation mechanisms.

  10. Genomic imprinting as a probable explanation for variable intrafamilial phenotypic expression of an unusual chromosome 3 abnormality

    SciTech Connect

    Fryburg, J.S.; Shashi, V.; Kelly, T.E.

    1994-09-01

    We present a 4 generation family in which an abnormal chromosome 3 with dup(3)(q25) segregated from great-grandmother to grandmother to son without phenotypic effect. The son`s 2 daughters have dysmorphic features, mild developmental delays and congenital heart disease. Both girls have the abnormal chr. 3 but are the only family members with the abnormality to have phenotypic effects. An unaffected son of the father has normal chromosomes. FISH with whole chromosome paints for chromosomes 1, 2, 6, 7, 8, 14, 18, and 22 excluded these as the origin of the extra material. Chromosome 3-specific paint revealed a uniform pattern, suggesting that the extra material is from chromosome 3. Comparative genomic hybridization and DNA studies are pending. Possible explanations for the discordance in phenotypes between the 4th generation offspring and the first 3 generations include: an undetected rearrangement in the previous generations that is unbalanced in the two affected individuals; the chromosome abnormality may be a benign variant and unrelated to the phenotype; or, most likely, genomic imprinting. Genomic imprinting is suggested by the observation that a phenotypic effect was only seen after the chromosome was inherited from the father. The mothers in the first two generations appear to have passed the abnormal chr. 3 on without effect. This is an opportunity to delineate a region of the human genome affected by paternal imprinting.

  11. Mechanisms of activation of the paternally expressed genes by the Prader-Willi imprinting center in the Prader-Willi/Angelman syndromes domains

    PubMed Central

    Rabinovitz, Shiri; Kaufman, Yotam; Ludwig, Guy; Razin, Aharon; Shemer, Ruth

    2012-01-01

    The Prader-Willi syndrome/Angelman syndrome (PWS/AS) imprinted domain is regulated by a bipartite imprinting control center (IC) composed of a sequence around the SNRPN promoter (PWS-IC) and a 880-bp sequence located 35 kb upstream (AS-IC). The AS-IC imprint is established during gametogenesis and confers repression upon PWS-IC on the maternal allele. Mutation at PWS-IC on the paternal allele leads to gene silencing across the entire PWS/AS domain. This silencing implies that PWS-IC functions on the paternal allele as a bidirectional activator. Here we examine the mechanism by which PWS-IC activates the paternally expressed genes (PEGs) using transgenes that include the PWS-IC sequence in the presence or absence of AS-IC and NDN, an upstream PEG, as an experimental model. We demonstrate that PWS-IC is in fact an activator of NDN. This activation requires an unmethylated PWS-IC in the gametes and during early embryogenesis. PWS-IC is dispensable later in development. Interestingly, a similar activation of a nonimprinted gene (APOA1) was observed, implying that PWS-IC is a universal activator. To decipher the mechanism by which PWS-IC confers activation of remote genes, we performed methylated DNA immunoprecipitation (MeDIP) array analysis on lymphoblast cell lines that revealed dispersed, rather than continued differential methylation. However, chromatin conformation capture (3c) experiments revealed a physical interaction between PWS-IC and the PEGs, suggesting that activation of PEGs may require their proximity to PWS-IC. PMID:22529396

  12. An unexpected function of the Prader-Willi syndrome imprinting center in maternal imprinting in mice.

    PubMed

    Wu, Mei-Yi; Jiang, Ming; Zhai, Xiaodong; Beaudet, Arthur L; Wu, Ray-Chang

    2012-01-01

    Genomic imprinting is a phenomenon that some genes are expressed differentially according to the parent of origin. Prader-Willi syndrome (PWS) and Angelman syndrome (AS) are neurobehavioral disorders caused by deficiency of imprinted gene expression from paternal and maternal chromosome 15q11-q13, respectively. Imprinted genes at the PWS/AS domain are regulated through a bipartite imprinting center, the PWS-IC and AS-IC. The PWS-IC activates paternal-specific gene expression and is responsible for the paternal imprint, whereas the AS-IC functions in the maternal imprint by allele-specific repression of the PWS-IC to prevent the paternal imprinting program. Although mouse chromosome 7C has a conserved PWS/AS imprinted domain, the mouse equivalent of the human AS-IC element has not yet been identified. Here, we suggest another dimension that the PWS-IC also functions in maternal imprinting by negatively regulating the paternally expressed imprinted genes in mice, in contrast to its known function as a positive regulator for paternal-specific gene expression. Using a mouse model carrying a 4.8-kb deletion at the PWS-IC, we demonstrated that maternal transmission of the PWS-IC deletion resulted in a maternal imprinting defect with activation of the paternally expressed imprinted genes and decreased expression of the maternally expressed imprinted gene on the maternal chromosome, accompanied by alteration of the maternal epigenotype toward a paternal state spread over the PWS/AS domain. The functional significance of this acquired paternal pattern of gene expression was demonstrated by the ability to complement PWS phenotypes by maternal inheritance of the PWS-IC deletion, which is in stark contrast to paternal inheritance of the PWS-IC deletion that resulted in the PWS phenotypes. Importantly, low levels of expression of the paternally expressed imprinted genes are sufficient to rescue postnatal lethality and growth retardation in two PWS mouse models. These findings

  13. Association of in vitro fertilization with global and IGF2/H19 methylation variation in newborn twins.

    PubMed

    Loke, Y J; Galati, J C; Saffery, R; Craig, J M

    2015-04-01

    In vitro fertilization (IVF) and its subset intracytoplasmic sperm injection (ICSI), are widely used medical treatments for conception. There has been controversy over whether IVF is associated with adverse short- and long-term health outcomes of offspring. As with other prenatal factors, epigenetic change is thought to be a molecular mediator of any in utero programming effects. Most studies focused on DNA methylation at gene-specific and genomic level, with only a few on associations between DNA methylation and IVF. Using buccal epithelium from 208 twin pairs from the Peri/Postnatal Epigenetic Twin Study (PETS), we investigated associations between IVF and DNA methylation on a global level, using the proxies of Alu and LINE-1 interspersed repeats in addition to two locus-specific regulatory regions within IGF2/H19, controlling for 13 potentially confounding factors. Using multiple correction testing, we found strong evidence that IVF-conceived twins have lower DNA methylation in Alu, and weak evidence of lower methylation in one of the two IGF2/H19 regulatory regions and LINE-1, compared with naturally conceived twins. Weak evidence of a relationship between ICSI and DNA methylation within IGF2/H19 regulatory region was found, suggesting that one or more of the processes associated with IVF/ICSI may contribute to these methylation differences. Lower within- and between-pair DNA methylation variation was also found in IVF-conceived twins for LINE-1, Alu and one IGF2/H19 regulatory region. Although larger sample sizes are needed, our results provide additional insight to the possible influence of IVF and ICSI on DNA methylation. To our knowledge, this is the largest study to date investigating the association of IVF and DNA methylation.

  14. The tobacco-specific carcinogen-operated calcium channel promotes lung tumorigenesis via IGF2 exocytosis in lung epithelial cells

    PubMed Central

    Boo, Hye-Jin; Min, Hye-Young; Jang, Hyun-Ji; Yun, Hye Jeong; Smith, John Kendal; Jin, Quanri; Lee, Hyo-Jong; Liu, Diane; Kweon, Hee-Seok; Behrens, Carmen; Lee, J. Jack; Wistuba, Ignacio I.; Lee, Euni; Hong, Waun Ki; Lee, Ho-Young

    2016-01-01

    Nicotinic acetylcholine receptors (nAChRs) binding to the tobacco-specific carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) induces Ca2+ signalling, a mechanism that is implicated in various human cancers. In this study, we investigated the role of NNK-mediated Ca2+ signalling in lung cancer formation. We show significant overexpression of insulin-like growth factors (IGFs) in association with IGF-1R activation in human preneoplastic lung lesions in smokers. NNK induces voltage-dependent calcium channel (VDCC)-intervened calcium influx in airway epithelial cells, resulting in a rapid IGF2 secretion via the regulated pathway and thus IGF-1R activation. Silencing nAChR, α1 subunit of L-type VDCC, or various vesicular trafficking curators, including synaptotagmins and Rabs, or blockade of nAChR/VDCC-mediated Ca2+ influx significantly suppresses NNK-induced IGF2 exocytosis, transformation and tumorigenesis of lung epithelial cells. Publicly available database reveals inverse correlation between use of calcium channel blockers and lung cancer diagnosis. Our data indicate that NNK disrupts the regulated pathway of IGF2 exocytosis and promotes lung tumorigenesis. PMID:27666821

  15. The X-linked imprinted gene family Fthl17 shows predominantly female expression following the two-cell stage in mouse embryos

    PubMed Central

    Kobayashi, Shin; Fujihara, Yoshitaka; Mise, Nathan; Kaseda, Kazuhiro; Abe, Kuniya; Ishino, Fumitoshi; Okabe, Masaru

    2010-01-01

    Differences between male and female mammals are initiated by embryonic differentiation of the gonad into either a testis or an ovary. However, this may not be the sole determinant. There are reports that embryonic sex differentiation might precede and be independent of gonadal differentiation, but there is little molecular biological evidence for this. To test for sex differences in early-stage embryos, we separated male and female blastocysts using newly developed non-invasive sexing methods for transgenic mice expressing green fluorescent protein and compared the gene-expression patterns. From this screening, we found that the Fthl17 (ferritin, heavy polypeptide-like 17) family of genes was predominantly expressed in female blastocysts. This comprises seven genes that cluster on the X chromosome. Expression analysis based on DNA polymorphisms revealed that these genes are imprinted and expressed from the paternal X chromosome as early as the two-cell stage. Thus, by the time zygotic genome activation starts there are already differences in gene expression between male and female mouse embryos. This discovery will be important for the study of early sex differentiation, as clearly these differences arise before gonadal differentiation. PMID:20185572

  16. In brief: genomic imprinting and imprinting diseases.

    PubMed

    Horsthemke, Bernhard

    2014-04-01

    Genomic imprinting is an epigenetic process by which the male and the female germline confer different DNA methylation marks and histone modifications onto specific gene regions, so that one allele of an imprinted gene is active and the other one is silent. Since the dosage of imprinted genes is important for normal development, growth and behaviour, the loss or duplication of the active allele can cause disease.

  17. Fetal growth restriction and the programming of heart growth and cardiac insulin-like growth factor 2 expression in the lamb

    PubMed Central

    Wang, Kimberley C W; Zhang, Lei; McMillen, I Caroline; Botting, Kimberley J; Duffield, Jaime A; Zhang, Song; Suter, Catherine M; Brooks, Doug A; Morrison, Janna L

    2011-01-01

    Abstract Reduced growth in fetal life together with accelerated growth in childhood, results in a ∼50% greater risk of coronary heart disease in adult life. It is unclear why changes in patterns of body and heart growth in early life can lead to an increased risk of cardiovascular disease in adulthood. We aimed to investigate the role of the insulin-like growth factors in heart growth in the growth-restricted fetus and lamb. Hearts were collected from control and placentally restricted (PR) fetuses at 137–144 days gestation and from average (ABW) and low (LBW) birth weight lambs at 21 days of age. We quantified cardiac mRNA expression of IGF-1, IGF-2 and their receptors, IGF-1R and IGF-2R, using real-time RT-PCR and protein expression of IGF-1R and IGF-2R using Western blotting. Combined bisulphite restriction analysis was used to assess DNA methylation in the differentially methylated region (DMR) of the IGF-2/H19 locus and of the IGF-2R gene. In PR fetal sheep, IGF-2, IGF-1R and IGF-2R mRNA expression was increased in the heart compared to controls. LBW lambs had a greater left ventricle weight relative to body weight as well as increased IGF-2 and IGF-2R mRNA expression in the heart, when compared to ABW lambs. No changes in the percentage of methylation of the DMRs of IGF-2/H19 or IGF-2R were found between PR and LBW when compared to their respective controls. In conclusion, a programmed increased in cardiac gene expression of IGF-2 and IGF-2R may represent an adaptive response to reduced substrate supply (e.g. glucose and/or oxygen) in order to maintain heart growth and may be the underlying cause for increased ventricular hypertrophy and the associated susceptibility of cardiomyocytes to ischaemic damage later in life. PMID:21807611

  18. A human imprinting centre demonstrates conserved acquisition but diverged maintenance of imprinting in a mouse model for Angelman syndrome imprinting defects.

    PubMed

    Johnstone, Karen A; DuBose, Amanda J; Futtner, Christopher R; Elmore, Michael D; Brannan, Camilynn I; Resnick, James L

    2006-02-01

    Prader-Willi syndrome (PWS) and Angelman syndrome (AS) are caused by the loss of imprinted gene expression from chromosome 15q11-q13. Imprinted gene expression in the region is regulated by a bipartite imprinting centre (IC), comprising the PWS-IC and the AS-IC. The PWS-IC is a positive regulatory element required for bidirectional activation of a number of paternally expressed genes. The function of the AS-IC appears to be to suppress PWS-IC function on the maternal chromosome through a methylation imprint acquired during female gametogenesis. Here we have placed the entire mouse locus under the control of a human PWS-IC by targeted replacement of the mouse PWS-IC with the equivalent human region. Paternal inheritance of the human PWS-IC demonstrates for the first time that a positive regulatory element in the PWS-IC has diverged. These mice show postnatal lethality and growth deficiency, phenotypes not previously attributed directly to the affected genes. Following maternal inheritance, the human PWS-IC is able to acquire a methylation imprint in mouse oocytes, suggesting that acquisition of the methylation imprint is conserved. However, the imprint is lost in somatic cells, showing that maintenance has diverged. This maternal imprinting defect results in expression of maternal Ube3a-as and repression of Ube3a in cis, providing evidence that Ube3a is regulated by its antisense and creating the first reported mouse model for AS imprinting defects.

  19. Silencing of imprinted CDKN1C gene expression is associated with loss of CpG and histone H3 lysine 9 methylation at DMR-LIT1 in esophageal cancer.

    PubMed

    Soejima, Hidenobu; Nakagawachi, Tetsuji; Zhao, Wei; Higashimoto, Ken; Urano, Takeshi; Matsukura, Shiroh; Kitajima, Yoshihiko; Takeuchi, Makoto; Nakayama, Masahiro; Oshimura, Mitsuo; Miyazaki, Kohji; Joh, Keiichiro; Mukai, Tsunehiro

    2004-05-27

    The putative tumor suppressor CDKN1C is an imprinted gene at 11p15.5, a well-known imprinted region often deleted in tumors. The absence of somatic mutations and the frequent diminished expression in tumors would suggest that CDKN1C expression is regulated epigenetically. It has been, however, controversial whether the diminution is caused by imprinting disruption of the CDKN1C/LIT1 domain or by promoter hypermethylation of CDKN1C itself. To clarify this, we investigated the CpG methylation index of the CDKN1C promoter and the differentially methylated region of the LIT1 CpG island (differentially methylated region (DMR)-LIT1), an imprinting control region of the domain, and CDKN1C expression in esophageal cancer cell lines. CDKN1C expression was diminished in 10 of 17 lines and statistically correlated with the loss of methylation at DMR-LIT1 in all but three. However, there was no statistical correlation between CDKN1C promoter MI and CDKN1C expression. Furthermore, loss of CpG methylation was associated with loss of histone H3 lysine 9 (H3K9) methylation at DMR-LIT1. Histone modifications at CDKN1C promoter were not correlated with CDKN1C expression. The data suggested that the diminished CDKN1C expression is associated with the loss of methylation of CpG and H3K9 at DMR-LIT1, not by its own promoter CpG methylation, and is involved in esophageal cancer, implying that DMR-LIT1 epigenetically regulates CDKN1C expression not through histone modifications at CDKN1C promoter, but through that of DMR-LIT1.

  20. DHPLC-based method for DNA methylation analysis of differential methylated regions from imprinted genes.

    PubMed

    Couvert, P; Poirier, K; Carrié, A; Chalas, C; Jouannet, P; Beldjord, C; Bienvenu, T; Chelly, J; Kerjean, A

    2003-02-01

    The bisulfite genomic sequencing method is one of the most widely used techniques for methylation analysis in heterogeneous unbiased PCR, amplifying for both methylated and unmethylated alleles simultaneously. However, it requires labor-intensive and time-consuming cloning and sequencing steps. In the current study, we used a denaturing high-performance liquid chromatography (DHPLC) procedure in a complementary way with the bisulfite genomic sequencing to analyze the methylation of differentially methylated regions (DMRs) of imprinted genes. We showed reliable and reproducible results in distinguishing overall methylation profiles of DMRs regions of human SNRPN, H19, MEST/PEG1, LIT1, IGF2, TSSC5, WT1 antisense, and mouse H19, Mest/Peg1, Igf2R imprinted genes. These DHPLC profiles were in accordance with bisulfite genomic sequencing data and may serve as a type of "fingerprint," revealing the overall methylation status of DMRs associated with sample heterogeneity. We conclude that DHPLC analysis could be used to increase the throughput efficiency of methylation pattern analysis of imprinted genes after the bisulfite conversion of genomic DNA and unbiased PCR amplification.

  1. Demography, kinship, and the evolving theory of genomic imprinting.

    PubMed

    Brandvain, Yaniv; Van Cleve, Jeremy; Ubeda, Francisco; Wilkins, Jon F

    2011-07-01

    Genomic imprinting is the differential expression of an allele based on the parent of origin. Recent transcriptome-wide evaluations of the number of imprinted genes reveal complex patterns of imprinted expression among developmental stages and cell types. Such data demand a comprehensive evolutionary framework in which to understand the effect of natural selection on imprinted gene expression. We present such a framework for how asymmetries in demographic parameters and fitness effects can lead to the evolution of genomic imprinting and place recent theoretical advances in this framework. This represents a modern interpretation of the kinship theory, is well suited to studying populations with complex social interactions, and provides predictions which can be tested with forthcoming transcriptomic data. To understand the intricate phenotypic patterns that are emerging from the recent deluge of data, future investigations of genomic imprinting will require integrating evolutionary theory, transcriptomic data, developmental and functional genetics, and natural history.

  2. Germline mutation in NLRP2 (NALP2) in a familial imprinting disorder (Beckwith-Wiedemann Syndrome).

    PubMed

    Meyer, Esther; Lim, Derek; Pasha, Shanaz; Tee, Louise J; Rahman, Fatimah; Yates, John R W; Woods, C Geoffrey; Reik, Wolf; Maher, Eamonn R

    2009-03-01

    Beckwith-Wiedemann syndrome (BWS) is a fetal overgrowth and human imprinting disorder resulting from the deregulation of a number of genes, including IGF2 and CDKN1C, in the imprinted gene cluster on chromosome 11p15.5. Most cases are sporadic and result from epimutations at either of the two 11p15.5 imprinting centres (IC1 and IC2). However, rare familial cases may be associated with germline 11p15.5 deletions causing abnormal imprinting in cis. We report a family with BWS and an IC2 epimutation in which affected siblings had inherited different parental 11p15.5 alleles excluding an in cis mechanism. Using a positional-candidate gene approach, we found that the mother was homozygous for a frameshift mutation in exon 6 of NLRP2. While germline mutations in NLRP7 have previously been associated with familial hydatidiform mole, this is the first description of NLRP2 mutation in human disease and the first report of a trans mechanism for disordered imprinting in BWS. These observations are consistent with the hypothesis that NLRP2 has a previously unrecognised role in establishing or maintaining genomic imprinting in humans.

  3. Imprinted genes and human disease: an evolutionary perspective.

    PubMed

    Ubeda, Francisco; Wilkins, Jon F

    2008-01-01

    Imprinted genes have been associated with a wide range of diseases. Many of these diseases have symptoms that can be understood in the context of the evolutionary forces that favored imprinted expression at these loci. Modulation of perinatal growth and resource acquisition has played a central role in the evolution of imprinting and many of the diseases associated with imprinted genes involve some sort of growth or feeding disorder. In the first part of this chapter, we discuss the relationship between the evolution of imprinting and the clinical manifestations of imprinting-associated diseases. In the second half, we consider the variety of processes that can disrupt imprinted gene expression and function. We ask specifically if there is reason to believe that imprinted genes are particularly susceptible to deregulation-and whether a disruption of an imprinted gene is more likely to have deleterious consequences than a disruption of an unimprinted gene. There is more to a gene than its DNA sequence. C. H. Waddington used the term "epigenetic" to describe biological differences between tissues that result from the process of development. Waddington needed a new term to describe this variation which was neither the result of genotypic differences between the cells nor well described as phenotypic variation. We now understand that heritable modifications of the DNA--such as cytosine methylation--and aspects of chromatin structure--including histone modifications--are the mechanisms underlying what Waddington called the "epigenotype." Epigenetic modifications are established in particular cell lines during development and are responsible for the patterns of gene expression seen in different tissue types. In contemporary usage, the term epigenetic refers to heritable changes in gene expression that are not coded in the DNA sequence itself. In recent years, much attention has been paid to a particular type of epigenetic variation: genomic imprinting. In the case of

  4. Characterization of differentially methylated regions in 3 bovine imprinted genes: a model for studying human germ-cell and embryo development.

    PubMed

    Hansmann, T; Heinzmann, J; Wrenzycki, C; Zechner, U; Niemann, H; Haaf, T

    2011-01-01

    Correct imprinting is crucial for normal fetal and placental development in mammals. Experimental evidence in animal models and epidemiological studies in humans suggest that assisted reproductive technologies (ARTs) can interfere with imprinted gene regulation in gametogenesis and early embryogenesis. Bos taurus is an agriculturally important species in which ARTs are commonly employed. Because this species exhibits a similar preimplantation development and gestation length as humans, it is increasingly being used as a model for human germ-cell and embryo development. However, in contrast to humans and mice, there is relatively little information on bovine imprinted genes. Here, we characterized the bovine intergenic IGF2-H19 imprinting control region (ICR) spanning approximately 3 kb. We identified a 300-bp differentially methylated region (DMR) approximately 6 kb upstream of the H19 promoter, containing a CpG island with CTCF-binding site and high sequence similarity with the human intergenic ICR. Additional differentially methylated CpG islands lie -6 kb to -3 kb upstream of the promoter, however these are less conserved. Both classical bisulfite sequencing and bisulfite pyrosequencing demonstrated complete methylation of the IGF2-H19 ICR in sperm, complete demethylation in parthenogenetic embryos having only the female genome, and differential methylation in placental and somatic tissues. In addition, we established pyrosequencing assays for the previously reported bovine SNRPN and PEG3 DMRs. The observed methylation patterns were consistent with genomic imprinting in all analyzed tissues/cell types. The identified IGF2-H19 ICR and the developed quantitative methylation assays may prove useful for further studies on the relationship between ARTs and imprinting defects in the bovine model.

  5. Genomic imprinting--insights from studies in mice.

    PubMed

    Ferguson-Smith, Anne; Lin, Shau-Ping; Tsai, Chen-En; Youngson, Neil; Tevendale, Maxine

    2003-02-01

    A subset of mammalian genes is controlled by genomic imprinting. This process causes a gene to be expressed from only one chromosome homologue depending on whether it originally came from the egg or the sperm. Parental origin-specific gene regulation is controlled by epigenetic modifications to DNA and chromatin. Genomic imprinting is therefore a useful model system to study the epigenetic control of genome function. Here we consider the value of the mouse as an experimental organism to address questions about the role of imprinted genes, about the regulation of mono-allelic gene expression and about the evolution of the imprinting function and mechanism.

  6. The continuing quest to comprehend genomic imprinting.

    PubMed

    Miyoshi, N; Barton, S C; Kaneda, M; Hajkova, P; Surani, M A

    2006-01-01

    The discovery of the phenomenon of genomic imprinting in mammals showed that the parental genomes are functionally non-equivalent. Considerable advances have occurred in the field over the past 20 years, which has resulted in the identification and functional analysis of a number of imprinted genes the expression of which is determined by their parental origin. These genes belong to many diverse categories and they have been shown to regulate growth, complex aspects of mammalian physiology and behavior. Many aspects of the mechanism of imprinting have also been elucidated. However, the reasons for the evolution of genomic imprinting remain enigmatic. Further research is needed to determine if there is any relationship between the apparently diverse functions of imprinted genes in mammals, and their role in human diseases. It also remains to be seen what common features exist amongst the diverse imprinting control elements. The mechanisms involved in the erasure and re-establishment of imprints should provide deeper insights into epigenetic mechanisms of wide general interest.

  7. Glial cell line-derived neurotrophic factor alters the growth characteristics and genomic imprinting of mouse multipotent adult germline stem cells

    SciTech Connect

    Jung, Yoon Hee

    2010-03-10

    This study evaluated the essentiality of glial cell line-derived neurotrophic factor (GDNF) for in vitro culture of established mouse multipotent adult germline stem (maGS) cell lines by culturing them in the presence of GDNF, leukemia inhibitory factor (LIF) or both. We show that, in the absence of LIF, GDNF slows the proliferation of maGS cells and result in smaller sized colonies without any change in distribution of cells to different cell-cycle stages, expression of pluripotency genes and in vitro differentiation potential. Furthermore, in the absence of LIF, GDNF increased the expression of male germ-line genes and repopulated the empty seminiferous tubule of W/W{sup v} mutant mouse without the formation of teratoma. GDNF also altered the genomic imprinting of Igf2, Peg1, and H19 genes but had no effect on DNA methylation of Oct4, Nanog and Stra8 genes. However, these effects of GDNF were masked in the presence of LIF. GDNF also did not interfere with the multipotency of maGS cells if they are cultured in the presence of LIF. In conclusion, our results suggest that, in the absence of LIF, GDNF alters the growth characteristics of maGS cells and partially impart them some of the germline stem (GS) cell-like characteristics.

  8. Molecularly Imprinted Ionomers

    DTIC Science & Technology

    2002-04-05

    ion selective electrodes and ion selective optical sensors using a modified version of the molecular imprinting technique. The modification is a...materials may be the means to realize this goal. An additional application of metal ion imprinted polymers is as sensors . The ability to detect a...been shown to have dramatic effects on polymer properties. The benefits of ionic crosslinking on molecular imprinting are two-fold. First, ionic

  9. Expression and DNA methylation analysis of SNRPN in Prader-Willi patients

    SciTech Connect

    Glenn, C.C.; Jong, M.T.C.; Driscoll, D.J.

    1994-09-01

    The human SNRPN gene is one of a gene family that encode proteins involved in pre-mRNA splicing and maps to the Prader-Willi syndrome critical region in 15q11-q13. We have previously demonstrated functional imprinting of SNRPN, with absent expression in PWS skin fibroblasts and lymphoblasts. We now show a similar lack of expression in blood of PWS patients, which appear to correlate with DNA methylation of NotI sites in the 5{prime} region of the gene. RNA and DNA was extracted from peripheral blood of Prader-Willi syndrome (PWS) and Angelman syndrome (AS) deletion patients to be used for RT-PCR with SNRPN gene-specific primers and DNA methylation analysis. Either no or highly reduced levels of SNRPN RT-PCR product were detected in nine PWS samples but was present in normals, AS patients, and one clinically typical PWS patient. Parent-of-origin DNA methylation imprints are also present within the SNRPN gene. PWS patients having only a maternal contribution of SNRPN have several NotI restriction sites near the transcription start site which are methylated, while these same sites are unmethylated on the paternal chromosome (i.e., AS samples). Several CpG sites approximately 22 kb downstream of the transcription start site are methylated preferentially on the paternal allele. These observations for human SNRPN are similar to those of the mouse imprinted gene Igf2r, which exhibits DNA methylation of a CpG island 27 kb from the transcription start site on the expressed allele, and DNA methylation in the promoter region of the repressed allele. We suggest that RT-PCR and/or DNA methylation analysis from blood of PWS patients may be the most accurate means of diagnosing classical PWS. These results further indicate a role for SNRPN in the pathogenesis of PWS, and may serve as a model to study other human imprinted genes.

  10. Evolution of genomic imprinting: insights from marsupials and monotremes.

    PubMed

    Renfree, Marilyn B; Hore, Timothy A; Shaw, Geoffrey; Graves, Jennifer A Marshall; Pask, Andrew J

    2009-01-01

    Parent-of-origin gene expression (genomic imprinting) is widespread among eutherian mammals and also occurs in marsupials. Most imprinted genes are expressed in the placenta, but the brain is also a favored site. Although imprinting evolved in therian mammals before the marsupial-eutherian split, the mechanisms have continued to evolve in each lineage to produce differences between the two groups in terms of the number and regulation of imprinted genes. As yet there is no evidence for genomic imprinting in the egg-laying monotreme mammals, although these mammals also form a placenta (albeit short-lived) and transfer nutrients from mother to embryo. Therefore, imprinting was not essential for the evolution of the placenta and its importance in nutrient transfer but the elaboration of imprinted genes in marsupials and eutherians is associated with viviparity. Here we review the recent analyses of imprinted gene clusters in marsupials and monotremes, which have served to shed light on the origin and evolution of imprinting mechanisms in mammals.

  11. Characterization of Conserved and Nonconserved Imprinted Genes in Swine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genomic imprinting results in the silencing of a subset of mammalian alleles due to parent-of-origin inheritance. Due to the nature of their expression patterns they play a critical role in placental and early embryonic development. In order to increase our understanding of imprinted genes specifi...

  12. [Epigenetic modification of the genetic material. Genomic imprinting and its significance for disease in human beings].

    PubMed

    Brøndum-Nielsen, K; Pedersen, M L

    2001-06-04

    Genomic imprinting is the epigenetic differential marking of maternally and paternally inherited alleles of specific genes or chromosomal subregions during gametogenesis, leading after fertilization to differential expression during development. Expression is thus monoallelic, with one parental allele being expressed, the other silenced. Imprinting implies the existence of a reversible imprinting signal, which is erased in the gonads to be reset according to the sex of the individual. Mutations in imprinted genes are not inherited in a regular Mendelian fashion. The number of identified imprinted genes is now around 35. Three congenital human disorders are known to be caused by errors in the expression pattern of imprinted genes: Prader-Willi syndrome, Angelman syndrome and Beckwith-Wiedemann syndrome. A number of cancers are also caused by errors in imprinted genes.

  13. Allele-specific deposition of macroH2A1 in Imprinting Control Regions

    SciTech Connect

    Choo, J H; Kim, J D; Chung, J H; Stubbs, L; Kim, J

    2006-01-13

    In the current study, we analyzed the deposition patterns of macroH2A1 at a number of different genomic loci located in X chromosome and autosomes. MacroH2A1 is preferentially deposited at methylated CpG CpG-rich regions located close to promoters. The macroH2A1 deposition patterns at the methylated CpG islands of several imprinted domains, including the Imprinting Control Regions (ICRs) of Xist, Peg3, H19/Igf2 Igf2, Gtl2/Dlk1, and Gnas domains, show consistent allele-specificity towards inactive, methylated alleles. The macroH2A1 deposition levels at the ICRs and other Differentially Methylated Regions (DMRs) of these domains are also either higher or comparable to those observed at the inactive X chromosome of female mammals. Overall, our results indicate that besides DNA methylation macroH2A1 is another epigenetic component in the chromatin of ICRs displaying differential association with two parental alleles.

  14. Epigenomic landscape modified by histone modification correlated with activation of IGF2 gene

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The links of histone post-translational modifications and chromatin structure to cell cycle progression, DNA replication, and overall chromosome functions are very clear. The modulation of genome expression as a consequence of chromatin structural changes is most likely a basic mechanism. The epige...

  15. Oligonucleofide Imprinting in Aqueous Environment

    DTIC Science & Technology

    2002-04-05

    imprint molecule for various organic and aqueous polymerization formulations (Table I). The polymer ...interactions (Table 1). Table 1. Polymer formulations used to imprint adenosine dimer 1. Molecularly imprinted polymer ( MIP ) using 1% dimer 1 as template ( MIP ... MIP P3 is compared to its rebinding with non- imprinted polymer P30. Cb is the amount of dimer rebound to the polymer . Cf is the

  16. Regulatory links between imprinted genes: evolutionary predictions and consequences.

    PubMed

    Patten, Manus M; Cowley, Michael; Oakey, Rebecca J; Feil, Robert

    2016-02-10

    Genomic imprinting is essential for development and growth and plays diverse roles in physiology and behaviour. Imprinted genes have traditionally been studied in isolation or in clusters with respect to cis-acting modes of gene regulation, both from a mechanistic and evolutionary point of view. Recent studies in mammals, however, reveal that imprinted genes are often co-regulated and are part of a gene network involved in the control of cellular proliferation and differentiation. Moreover, a subset of imprinted genes acts in trans on the expression of other imprinted genes. Numerous studies have modulated levels of imprinted gene expression to explore phenotypic and gene regulatory consequences. Increasingly, the applied genome-wide approaches highlight how perturbation of one imprinted gene may affect other maternally or paternally expressed genes. Here, we discuss these novel findings and consider evolutionary theories that offer a rationale for such intricate interactions among imprinted genes. An evolutionary view of these trans-regulatory effects provides a novel interpretation of the logic of gene networks within species and has implications for the origin of reproductive isolation between species.

  17. Regulatory links between imprinted genes: evolutionary predictions and consequences

    PubMed Central

    Patten, Manus M.; Cowley, Michael; Oakey, Rebecca J.; Feil, Robert

    2016-01-01

    Genomic imprinting is essential for development and growth and plays diverse roles in physiology and behaviour. Imprinted genes have traditionally been studied in isolation or in clusters with respect to cis-acting modes of gene regulation, both from a mechanistic and evolutionary point of view. Recent studies in mammals, however, reveal that imprinted genes are often co-regulated and are part of a gene network involved in the control of cellular proliferation and differentiation. Moreover, a subset of imprinted genes acts in trans on the expression of other imprinted genes. Numerous studies have modulated levels of imprinted gene expression to explore phenotypic and gene regulatory consequences. Increasingly, the applied genome-wide approaches highlight how perturbation of one imprinted gene may affect other maternally or paternally expressed genes. Here, we discuss these novel findings and consider evolutionary theories that offer a rationale for such intricate interactions among imprinted genes. An evolutionary view of these trans-regulatory effects provides a novel interpretation of the logic of gene networks within species and has implications for the origin of reproductive isolation between species. PMID:26842569

  18. Genomic imprinting and position-effect variegation in Drosophila melanogaster.

    PubMed Central

    Lloyd, V K; Sinclair, D A; Grigliatti, T A

    1999-01-01

    Genomic imprinting is a phenomenon in which the expression of a gene or chromosomal region depends on the sex of the individual transmitting it. The term imprinting was first coined to describe parent-specific chromosome behavior in the dipteran insect Sciara and has since been described in many organisms, including other insects, plants, fish, and mammals. In this article we describe a mini-X chromosome in Drosophila melanogaster that shows genomic imprinting of at least three closely linked genes. The imprinting of these genes is observed as mosaic silencing when the genes are transmitted by the male parent, in contrast to essentially wild-type expression when the same genes are maternally transmitted. We show that the imprint is due to the sex of the parent rather than to a conventional maternal effect, differential mitotic instability of the mini-X chromosome, or an allele-specific effect. Finally, we have examined the effects of classical modifiers of position-effect variegation on the maintenance and the establishment of the imprint. Factors that modify position-effect variegation alter the somatic expression but not the establishment of the imprint. This suggests that chromatin structure is important in maintenance of the imprint, but a separate mechanism may be responsible for its initiation. PMID:10101173

  19. Genomic imprinting and human psychology: cognition, behavior and pathology.

    PubMed

    Goos, Lisa M; Ragsdale, Gillian

    2008-01-01

    Imprinted genes expressed in the brain are numerous and it has become clear that they play an important role in nervous system development and function. The significant influence of genomic imprinting during development sets the stage for structural and physiological variations affecting psychological function and behaviour, as well as other physiological systems mediating health and well-being. However, our understanding of the role of imprinted genes in behaviour lags far behind our understanding of their roles in perinatal growth and development. Knowledge of genomic imprinting remains limited among behavioral scientists and clinicians and research regarding the influence of imprinted genes on normal cognitive processes and the most common forms of neuropathology has been limited to date. In this chapter, we will explore how knowledge of genomic imprinting can be used to inform our study of normal human cognitive and behavioral processes as well as their disruption. Behavioural analyses of rare imprinted disorders, such as Prader-Willi and Angelman syndromes, provide insight regarding the phenotypic impact of imprinted genes in the brain, and can be used to guide the study of normal behaviour as well as more common but etiologically complex disorders such as ADHD and autism. Furthermore, hypotheses regarding the evolutionary development of imprinted genes can be used to derive predictions about their role in normal behavioural variation, such as that observed in food-related and social interactions.

  20. BACs as tools for the study of genomic imprinting.

    PubMed

    Tunster, S J; Van De Pette, M; John, R M

    2011-01-01

    Genomic imprinting in mammals results in the expression of genes from only one parental allele. Imprinting occurs as a consequence of epigenetic marks set down either in the father's or the mother's germ line and affects a very specific category of mammalian gene. A greater understanding of this distinctive phenomenon can be gained from studies using large genomic clones, called bacterial artificial chromosomes (BACs). Here, we review the important applications of BACs to imprinting research, covering physical mapping studies and the use of BACs as transgenes in mice to study gene expression patterns, to identify imprinting centres, and to isolate the consequences of altered gene dosage. We also highlight the significant and unique advantages that rapid BAC engineering brings to genomic imprinting research.

  1. Mechanisms and evolution of genomic imprinting in plants.

    PubMed

    Köhler, C; Weinhofer-Molisch, I

    2010-07-01

    Genomic imprinting, the allele-specific expression of a gene dependent on its parent-of-origin, has independently evolved in flowering plants and mammals. In mammals and flowering plants, imprinting occurs in the embryo as well as in embryo-nourishing tissues, the placenta and the endosperm, respectively, and it has been suggested that imprinted genes control the nutrient flow from the mother to the offspring ('kinship theory'). Alternatively, imprinting might have evolved as a by-product of a defense mechanism destined to control transposon activity in gametes ('defense hypothesis'). Recent studies provide substantial evidence for the 'defense hypothesis' by showing that imprinted genes in plants are located in the vicinity of transposon or repeat sequences, suggesting that the insertion of transposon or repeat sequences was a prerequisite for imprinting evolution. Transposons or repeat sequences are silenced by DNA methylation, causing silencing of neighboring genes in vegetative tissues. However, because of genome-wide DNA demethylation in the central cell, genes located in the vicinity of transposon or repeat sequences will be active in the central cell and the maternal alleles will remain unmethylated and active in the descendent endosperm, assuming an imprinted expression. Consequently, many imprinted genes are likely to have an endosperm-restricted function, or, alternatively, they have no functional role in the endosperm and are on the trajectory to convert to pseudogenes. Thus, the 'defense hypothesis' as well as 'kinship theory' together can explain the origin of genomic imprinting; whereas the first hypothesis explains how imprinting originates, the latter explains how imprinting is manifested and maintained.

  2. Variable imprinting of the MEST gene in human preimplantation embryos

    PubMed Central

    Huntriss, John D; Hemmings, Karen E; Hinkins, Matthew; Rutherford, Anthony J; Sturmey, Roger G; Elder, Kay; Picton, Helen M

    2013-01-01

    There is evidence that expression and methylation of the imprinted paternally expressed gene 1/mesoderm-specific transcript homologue (PEG1/MEST) gene may be affected by assisted reproductive technologies (ARTs) and infertility. In this study, we sought to assess the imprinting status of the MEST gene in a large cohort of in vitro-derived human preimplantation embryos, in order to characterise potentially adverse effects of ART and infertility on this locus in early human development. Embryonic genomic DNA from morula or blastocyst stage embryos was screened for a transcribed AflIII polymorphism in MEST and imprinting analysis was then performed in cDNA libraries derived from these embryos. In 10 heterozygous embryos, MEST expression was monoallelic in seven embryos, predominantly monoallelic in two embryos, and biallelic in one embryo. Screening of cDNA derived from 61 additional human preimplantation embryos, for which DNA for genotyping was unavailable, identified eight embryos with expression originating from both alleles (biallelic or predominantly monoallelic). In some embryos, therefore, the onset of imprinted MEST expression occurs during late preimplantation development. Variability in MEST imprinting was observed in both in vitro fertilization and intracytoplasmic sperm injection-derived embryos. Biallelic or predominantly monoallelic MEST expression was not associated with any one cause of infertility. Characterisation of the main MEST isoforms revealed that isoform 2 was detected in early development and was itself variably imprinted between embryos. To our knowledge, this report constitutes the largest expression study to date of genomic imprinting in human preimplantation embryos and reveals that for some imprinted genes, contrasting imprinting states exist between embryos. PMID:22763377

  3. Genomic Imprinting in the Arabidopsis Embryo Is Partly Regulated by PRC2

    PubMed Central

    Raissig, Michael T.; Bemer, Marian; Baroux, Célia; Grossniklaus, Ueli

    2013-01-01

    Genomic imprinting results in monoallelic gene expression in a parent-of-origin-dependent manner and is regulated by the differential epigenetic marking of the parental alleles. In plants, genomic imprinting has been primarily described for genes expressed in the endosperm, a tissue nourishing the developing embryo that does not contribute to the next generation. In Arabidopsis, the genes MEDEA (MEA) and PHERES1 (PHE1), which are imprinted in the endosperm, are also expressed in the embryo; whether their embryonic expression is regulated by imprinting or not, however, remains controversial. In contrast, the maternally expressed in embryo 1 (mee1) gene of maize is clearly imprinted in the embryo. We identified several imprinted candidate genes in an allele-specific transcriptome of hybrid Arabidopsis embryos and confirmed parent-of-origin-dependent, monoallelic expression for eleven maternally expressed genes (MEGs) and one paternally expressed gene (PEG) in the embryo, using allele-specific expression analyses and reporter gene assays. Genetic studies indicate that the Polycomb Repressive Complex 2 (PRC2) but not the DNA METHYLTRANSFERASE1 (MET1) is involved in regulating imprinted expression in the embryo. In the seedling, all embryonic MEGs and the PEG are expressed from both parents, suggesting that the imprint is erased during late embryogenesis or early vegetative development. Our finding that several genes are regulated by genomic imprinting in the Arabidopsis embryo clearly demonstrates that this epigenetic phenomenon is not a unique feature of the endosperm in both monocots and dicots. PMID:24339783

  4. Genomic imprinting in the Arabidopsis embryo is partly regulated by PRC2.

    PubMed

    Raissig, Michael T; Bemer, Marian; Baroux, Célia; Grossniklaus, Ueli

    2013-01-01

    Genomic imprinting results in monoallelic gene expression in a parent-of-origin-dependent manner and is regulated by the differential epigenetic marking of the parental alleles. In plants, genomic imprinting has been primarily described for genes expressed in the endosperm, a tissue nourishing the developing embryo that does not contribute to the next generation. In Arabidopsis, the genes MEDEA (MEA) and PHERES1 (PHE1), which are imprinted in the endosperm, are also expressed in the embryo; whether their embryonic expression is regulated by imprinting or not, however, remains controversial. In contrast, the maternally expressed in embryo 1 (mee1) gene of maize is clearly imprinted in the embryo. We identified several imprinted candidate genes in an allele-specific transcriptome of hybrid Arabidopsis embryos and confirmed parent-of-origin-dependent, monoallelic expression for eleven maternally expressed genes (MEGs) and one paternally expressed gene (PEG) in the embryo, using allele-specific expression analyses and reporter gene assays. Genetic studies indicate that the Polycomb Repressive Complex 2 (PRC2) but not the DNA METHYLTRANSFERASE1 (MET1) is involved in regulating imprinted expression in the embryo. In the seedling, all embryonic MEGs and the PEG are expressed from both parents, suggesting that the imprint is erased during late embryogenesis or early vegetative development. Our finding that several genes are regulated by genomic imprinting in the Arabidopsis embryo clearly demonstrates that this epigenetic phenomenon is not a unique feature of the endosperm in both monocots and dicots.

  5. Imprinting in plants as a mechanism to generate seed phenotypic diversity

    PubMed Central

    Bai, Fang; Settles, A. M.

    2015-01-01

    Normal plant development requires epigenetic regulation to enforce changes in developmental fate. Genomic imprinting is a type of epigenetic regulation in which identical alleles of genes are expressed in a parent-of-origin dependent manner. Deep sequencing of transcriptomes has identified hundreds of imprinted genes with scarce evidence for the developmental importance of individual imprinted loci. Imprinting is regulated through global DNA demethylation in the central cell prior to fertilization and directed repression of individual loci with the Polycomb Repressive Complex 2 (PRC2). There is significant evidence for transposable elements and repeat sequences near genes acting as cis-elements to determine imprinting status of a gene, implying that imprinted gene expression patterns may evolve randomly and at high frequency. Detailed genetic analysis of a few imprinted loci suggests an imprinted pattern of gene expression is often dispensable for seed development. Few genes show conserved imprinted expression within or between plant species. These data are not fully explained by current models for the evolution of imprinting in plant seeds. We suggest that imprinting may have evolved to provide a mechanism for rapid neofunctionalization of genes during seed development to increase phenotypic diversity of seeds. PMID:25674092

  6. Selection in the Making: A Worldwide Survey of Haplotypic Diversity Around a Causative Mutation in Porcine IGF2

    PubMed Central

    Ojeda, A.; Huang, L.-S.; Ren, J.; Angiolillo, A.; Cho, I.-C.; Soto, H.; Lemús-Flores, C.; Makuza, S. M.; Folch, J. M.; Pérez-Enciso, M.

    2008-01-01

    Domestic species allow us to study dramatic evolutionary changes at an accelerated rate due to the effectiveness of modern breeding techniques and the availability of breeds that have undergone distinct selection pressures. We present a worldwide survey of haplotype variability around a known causative mutation in porcine gene IGF2, which increases lean content. We genotyped 34 SNPs spanning 27 kb in 237 domestic pigs and 162 wild boars. Although the selective process had wiped out variability for at least 27 kb in the haplotypes carrying the mutation, there was no indication of an overall reduction in genetic variability of international vs. European local breeds; there was also no evidence of a reduction in variability caused by domestication. The haplotype structure and a plot of Tajima's D against the frequency of the causative mutation across breeds suggested a temporal pattern, where each breed corresponded to a different selective stage. This was observed comparing the haplotype neighbor-joining (NJ) trees of breeds that have undergone increasing selection pressures for leanness, e.g., European local breeds vs. Pietrain. These results anticipate that comparing current domestic breeds will decisively help to recover the genetic history of domestication and contemporary selective processes. PMID:18245828

  7. Molecularly Imprinted Biodegradable Nanoparticles

    PubMed Central

    Gagliardi, Mariacristina; Bertero, Alice; Bifone, Angelo

    2017-01-01

    Biodegradable polymer nanoparticles are promising carriers for targeted drug delivery in nanomedicine applications. Molecu- lar imprinting is a potential strategy to target polymer nanoparticles through binding of endogenous ligands that may promote recognition and active transport into specific cells and tissues. However, the lock-and-key mechanism of molecular imprinting requires relatively rigid cross-linked structures, unlike those of many biodegradable polymers. To date, no fully biodegradable molecularly imprinted particles have been reported in the literature. This paper reports the synthesis of a novel molecularly- imprinted nanocarrier, based on poly(lactide-co-glycolide) (PLGA) and acrylic acid, that combines biodegradability and molec- ular recognition properties. A novel three-arm biodegradable cross-linker was synthesized by ring-opening polymerization of glycolide and lactide initiated by glycerol. The resulting macromer was functionalized by introduction of end-functions through reaction with acryloyl chloride. Macromer and acrylic acid were used for the synthesis of narrowly-dispersed nanoparticles by radical polymerization in diluted conditions in the presence of biotin as template molecule. The binding capacity of the imprinted nanoparticles towards biotin and biotinylated bovine serum albumin was twentyfold that of non-imprinted nanoparti- cles. Degradation rates and functional performances were assessed in in vitro tests and cell cultures, demonstrating effective biotin-mediated cell internalization. PMID:28071745

  8. Molecularly Imprinted Biodegradable Nanoparticles

    NASA Astrophysics Data System (ADS)

    Gagliardi, Mariacristina; Bertero, Alice; Bifone, Angelo

    2017-01-01

    Biodegradable polymer nanoparticles are promising carriers for targeted drug delivery in nanomedicine applications. Molecu- lar imprinting is a potential strategy to target polymer nanoparticles through binding of endogenous ligands that may promote recognition and active transport into specific cells and tissues. However, the lock-and-key mechanism of molecular imprinting requires relatively rigid cross-linked structures, unlike those of many biodegradable polymers. To date, no fully biodegradable molecularly imprinted particles have been reported in the literature. This paper reports the synthesis of a novel molecularly- imprinted nanocarrier, based on poly(lactide-co-glycolide) (PLGA) and acrylic acid, that combines biodegradability and molec- ular recognition properties. A novel three-arm biodegradable cross-linker was synthesized by ring-opening polymerization of glycolide and lactide initiated by glycerol. The resulting macromer was functionalized by introduction of end-functions through reaction with acryloyl chloride. Macromer and acrylic acid were used for the synthesis of narrowly-dispersed nanoparticles by radical polymerization in diluted conditions in the presence of biotin as template molecule. The binding capacity of the imprinted nanoparticles towards biotin and biotinylated bovine serum albumin was twentyfold that of non-imprinted nanoparti- cles. Degradation rates and functional performances were assessed in in vitro tests and cell cultures, demonstrating effective biotin-mediated cell internalization.

  9. Molecularly Imprinted Biodegradable Nanoparticles.

    PubMed

    Gagliardi, Mariacristina; Bertero, Alice; Bifone, Angelo

    2017-01-10

    Biodegradable polymer nanoparticles are promising carriers for targeted drug delivery in nanomedicine applications. Molecu- lar imprinting is a potential strategy to target polymer nanoparticles through binding of endogenous ligands that may promote recognition and active transport into specific cells and tissues. However, the lock-and-key mechanism of molecular imprinting requires relatively rigid cross-linked structures, unlike those of many biodegradable polymers. To date, no fully biodegradable molecularly imprinted particles have been reported in the literature. This paper reports the synthesis of a novel molecularly- imprinted nanocarrier, based on poly(lactide-co-glycolide) (PLGA) and acrylic acid, that combines biodegradability and molec- ular recognition properties. A novel three-arm biodegradable cross-linker was synthesized by ring-opening polymerization of glycolide and lactide initiated by glycerol. The resulting macromer was functionalized by introduction of end-functions through reaction with acryloyl chloride. Macromer and acrylic acid were used for the synthesis of narrowly-dispersed nanoparticles by radical polymerization in diluted conditions in the presence of biotin as template molecule. The binding capacity of the imprinted nanoparticles towards biotin and biotinylated bovine serum albumin was twentyfold that of non-imprinted nanoparti- cles. Degradation rates and functional performances were assessed in in vitro tests and cell cultures, demonstrating effective biotin-mediated cell internalization.

  10. The role of genomic imprinting in biology and disease: an expanding view.

    PubMed

    Peters, Jo

    2014-08-01

    Genomic imprinting is an epigenetic phenomenon that results in monoallelic gene expression according to parental origin. It has long been established that imprinted genes have major effects on development and placental biology before birth. More recently, it has become evident that imprinted genes also have important roles after birth. In this Review, I bring together studies of the effects of imprinted genes from the prenatal period onwards. Recent work on postnatal stages shows that imprinted genes influence an extraordinarily wide-ranging array of biological processes, the effects of which extend into adulthood, and play important parts in common diseases that range from obesity to psychiatric disorders.

  11. Human imprinting anomalies in fetal and childhood growth disorders: clinical implications and molecular mechanisms.

    PubMed

    Azzi, Salah; Brioude, Fréderic; Le Bouc, Yves; Netchine, Irène

    2014-01-01

    Genomic imprinting is among the most important epigenetic mechanisms whereby expression of a subset of genes is restricted to a single parental allele. Loss of imprinting (LOI) through hypo or hyper methylation is involved in various human syndromes. These LOI occur early during development and usually impair growth. Some imprinting syndromes are the consequences of genetic anomalies, such as uniparental disomies (UPD) or copy number variations (deletion or duplications) involving the imprinted domains; others are due to LOI at the imprinting control regions (ICR) regulating each domain. Imprinting disorders are phenotypically heterogeneous, although some share various common clinical features such that diagnosis may be difficult. Multilocus imprinting defects associated with several syndromes have been increasingly reported in recent years, although there are no obvious clinical differences between monolocus and multilocus LOI patients. Subsequently, some rare mutations of transacting factors have been identified in patients with multilocus imprinting defects but they do not explain the majority of the cases; this therefore implies that other factors are involved. By contrast, no mutation of a transacting factor has yet been identified in monolocus LOI. The effect of the environment on the regulation of imprinting is clearly illustrated by studies of assisted reproductive technology (ART). The regulation of imprinting is complex and involves a huge range of genetic and environmental factors; the identification of these factors will undoubtedly help to elucidate the regulation of imprinting and contribute to the understanding of imprinting disorders. This would be beneficial for diagnostics, clinical follow up and the development of treatment guidelines.

  12. Genomic imprinting in the human placenta.

    PubMed

    Monk, David

    2015-10-01

    With the launch of the National Institute of Child Health and Human Development/National Institutes of Health Human Placenta Project, the anticipation is that this often-overlooked organ will be the subject of much intense research. Compared with somatic tissues, the cells of the placenta have a unique epigenetic profile that dictates its transcription patterns, which when disturbed may be associated with adverse pregnancy outcomes. One major class of genes that is dependent on strict epigenetic regulation in the placenta is subject to genomic imprinting, the parent-of-origin-dependent monoallelic gene expression. This review discusses the differences in allelic expression and epigenetic profiles of imprinted genes that are identified between different species, which reflect the continuous evolutionary adaption of this form of epigenetic regulation. These observations divulge that placenta-specific imprinted gene that is reliant on repressive histone signatures in mice are unlikely to be imprinted in humans, whereas intense methylation profiling in humans has uncovered numerous maternally methylated regions that are restricted to the placenta that are not conserved in mice. Imprinting has been proposed to be a mechanism that regulates parental resource allocation and ultimately can influence fetal growth, with the placenta being the key in this process. Furthermore, I discuss the developmental dynamics of both classic and transient placenta-specific imprinting and examine the evidence for an involvement of these genes in intrauterine growth restriction and placenta-associated complications. Finally, I focus on examples of genes that are regulated aberrantly in complicated pregnancies, emphasizing their application as pregnancy-related disease biomarkers to aid the diagnosis of at-risk pregnancies early in gestation.

  13. Genomic imprinting and the social brain.

    PubMed

    Isles, Anthony R; Davies, William; Wilkinson, Lawrence S

    2006-12-29

    Genomic imprinting refers to the parent-of-origin-specific epigenetic marking of a number of genes. This epigenetic mark leads to a bias in expression between maternally and paternally inherited imprinted genes, that in some cases results in monoallelic expression from one parental allele. Genomic imprinting is often thought to have evolved as a consequence of the intragenomic conflict between the parental alleles that occurs whenever there is an asymmetry of relatedness. The two main examples of asymmetry of relatedness are when there is partiality of parental investment in offspring (as is the case for placental mammals, where there is also the possibility of extended postnatal care by one parent), and in social groups where there is a sex-biased dispersal. From this evolutionary starting point, it is predicted that, at the behavioural level, imprinted genes will influence what can broadly be termed bonding and social behaviour. We examine the animal and human literature for examples of imprinted genes mediating these behaviours, and divide them into two general classes. Firstly, mother-offspring interactions (suckling, attachment and maternal behaviours) that are predicted to occur when partiality in parental investment in early postnatal offspring occurs; and secondly, adult social interactions, when there is an asymmetry of relatedness in social groups. Finally, we return to the evolutionary theory and examine whether there is a pattern of behavioural functions mediated by imprinted genes emerging from the limited data, and also whether any tangible predictions can be made with regards to the direction of action of genes of maternal or paternal origin.

  14. No detectable association of IGF2BP2 and SLC30A8 genes with type 2 diabetes in the population of Hyderabad, India.

    PubMed

    Kommoju, Uma Jyothi; Maruda, Jayaraj; Kadarkarai, Subburaj; Irgam, Kumuda; Kotla, Jaya Prasad; Velaga, Lakshmi; Mohan Reddy, Battini

    2013-12-01

    Genome-wide association studies identified novel genes associated with T2DM which have been replicated in different populations. We try to examine here if certain frequently replicated SNPs of Insulin growth factor 2 m-RNA binding protein 2 (IGF2BP2) (rs4402960, rs1470579) and Solute Carrier family 30 member 8 (SLC30A8) (rs13266634) genes, known to be implicated in insulin pathway, are associated with T2DM in the population of Hyderabad, which is considered to be a diabetic capital of India. Genotyping of the 1379 samples, 758 cases and 621 controls, for the SNPs was performed on sequenom massarray platform. The logistic regression analysis was done using SPSS software and the post-hoc power of the study was estimated using G power. The allele and genotype frequencies were similar between cases and controls, both for SNPs of IGF2BP2 and SLC30A8 genes. Logistic regression did not reveal significant allelic or genotypic association of any of the three SNPs with T2DM. Despite large sample size and adequate power, we could not replicate the association of IGF2BP2 and SLC30A8 SNPs with T2DM in our sample from Hyderabad (A.P.), India, albeit another study based on much larger sample but from heterogeneous populations from the northern parts of India showed significant association of two of the above 3 SNPs, suggesting variable nature of susceptibility of these genes in different ethnic groups. Although the IGF2BP2 and SLC30A8 genes are important in the functional pathway of Insulin secretion, it appears that these genes do not play a significant role in the susceptibility to T2DM in this population.

  15. Association study of polymorphisms in FOXO3, AKT1 and IGF-2R genes with human longevity in a Han Chinese population

    PubMed Central

    Liu, Xiaoqi; Ma, Shi; Lin, He; Chen, Rong; Hao, Fang; Zhang, Dingding

    2016-01-01

    FOXO3, AKT1 and IGF-2R are critical members of the insulin/IGF-1 signaling pathway. Previous studies showed that polymorphisms (SNPs) in FOXO3, AKT1 and IGF-2R were associated with human longevity in Caucasian population. However, the association of these SNPs in different ethnic groups is often inconsistent. Here, we investigated the association of genetic variants in three genes with human longevity in Han Chinese population. Twelve SNPs from FOXO3, AKT1 and IGF-2R were selected and genotyped in 1202 long-lived individuals (nonagenarians and centenarians) and younger individuals. Rs9486902 of FOXO3 was found to be associated with human longevity in both genders combined in this study (allelic P = 0.002, corrected P = 0.024). The other eleven SNPs were not significantly associated with human longevity in Han Chinese population. The haplotypes TTCTT, CCTTC and CTCCT of FOXO3 as well as GGTCGG and GGTCAG of AKT1 were shown to have a significant difference between case and control (P =0.006, 2.78×10−5, 4.68×10−6, 0.003,0.005, respectively). The estimated prevalence of diabetes and prediabetes in long-lived individuals was significantly lower than in common adult populations (P = 0.001, 2.3×10−26). Therefore, the search for longevity-associated genes provides the identification of new potential targets beneficial for the treatment of diabetes. PMID:26683100

  16. IGF2BP2 rs11705701 polymorphisms are associated with prediabetes in a Chinese population: A population-based case-control study

    PubMed Central

    Han, Liyuan; Li, Yuanyuan; Tang, Linlin; Chen, Zhongwei; Zhang, Tao; Chen, Sihan; Liu, Shengyuan; Peng, Xiaolin; Mai, Yifeng; Zhuo, Renjie; Wang, Changyi; Duan, Shiwei

    2016-01-01

    Associations between insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) rs11705701, insulin receptor substrate 1 rs7578326, gastric inhibitory polypeptide receptor rs10423928 and transcription factor 7-like 2 rs12255372 gene polymorphisms with prediabetes and type 2 diabetes (T2D) have not been evaluated in the Han Chinese population. These four genetic variants were investigated for their associations with prediabetes and T2D among 490 unrelated patients with T2D, 471 patients with prediabetes and 575 healthy controls. Sequenom MassARRAY software was used to genotype the patients for these variants. The Generalized Multifactor Dimensionality Reduction method was used to analyze the gene-gene and gene-environment interactions. A breakdown analysis by gender revealed a significant association of IGF2BP2 rs11705701 with prediabetes under the dominant genetic model in females following application of the Bonferroni correction (odds ratio = 0.26; 95% confidence interval = 0.10–0.67; P=0.005). However, no significant associations were reported between any of the other three polymorphisms and T2D under any genetic models. Furthermore, there were no statistically significant gene-gene or gene-environment interactions when evaluated with the above association tests. The present case-control study reveals a significant association between IGF2BP2 rs11705701 and prediabetes in female patients. PMID:27588103

  17. Association study of polymorphisms in FOXO3, AKT1 and IGF-2R genes with human longevity in a Han Chinese population.

    PubMed

    Li, Ning; Luo, Huaichao; Liu, Xiaoqi; Ma, Shi; Lin, He; Chen, Rong; Hao, Fang; Zhang, Dingding

    2016-01-05

    FOXO3, AKT1 and IGF-2R are critical members of the insulin/IGF-1 signaling pathway. Previous studies showed that polymorphisms (SNPs) in FOXO3, AKT1 and IGF-2R were associated with human longevity in Caucasian population. However, the association of these SNPs in different ethnic groups is often inconsistent. Here, we investigated the association of genetic variants in three genes with human longevity in Han Chinese population. Twelve SNPs from FOXO3, AKT1 and IGF-2R were selected and genotyped in 1202 long-lived individuals (nonagenarians and centenarians) and younger individuals. Rs9486902 of FOXO3 was found to be associated with human longevity in both genders combined in this study (allelic P = 0.002, corrected P = 0.024). The other eleven SNPs were not significantly associated with human longevity in Han Chinese population. The haplotypes TTCTT, CCTTC and CTCCT of FOXO3 as well as GGTCGG and GGTCAG of AKT1 were shown to have a significant difference between case and control (P =0.006, 2.78×10-5, 4.68×10-6, 0.003,0.005, respectively). The estimated prevalence of diabetes and prediabetes in long-lived individuals was significantly lower than in common adult populations (P = 0.001, 2.3×10-26) .Therefore, the search for longevity-associated genes provides the identification of new potential targets beneficial for the treatment of diabetes.

  18. MC1R, KIT, IGF2, and NR6A1 as markers for genetic differentiation in Thai native, wild boars, and Duroc and Chinese Meishan pigs.

    PubMed

    Klomtong, P; Chaweewan, K; Phasuk, Y; Duangjinda, M

    2015-10-19

    Mutations in melanocortin 1 receptor (MC1R) gene and v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog (KIT) gene have been shown to affect coat color patterns in pigs. Additional functional marker genes, such as insulin like growth factor-2 (IGF2) and orphan nuclear receptor, germ cell nuclear factor (NR6A1), have been described for variations in factors such as fat deposition, litter size, and vertebra number in pigs. In this study, we investigated 129 pigs representing 4 breeds: Thai indigenous, classified into black (similar to Raad or Ka done pig) and black and white (similar to the Hailum and Kwai pig) coat color types; wild boar; Duroc; and Chinese Meishan. Mutations of MC1R, KIT, IGF2, and NR6A1 were detected using polymerase chain reaction-restriction fragment length polymorphism. The genotypes variation in MC1R and KIT genes could be used to differentiate four groups of coat color: solid black, black and white, red, and wild type. For IGF2, the GG genotype was present in wild boar only; for NR6A1 the TT genotype was found only in Duroc pigs. We identified novel 14-bp deletions in KIT that were associated with black and white coat color in Thai indigenous pigs. Insights into variations in genes presented in this study will be useful in future developmental breeding programs for the Thai native pig.

  19. Transcriptome-wide investigation of genomic imprinting in chicken.

    PubMed

    Frésard, Laure; Leroux, Sophie; Servin, Bertrand; Gourichon, David; Dehais, Patrice; Cristobal, Magali San; Marsaud, Nathalie; Vignoles, Florence; Bed'hom, Bertrand; Coville, Jean-Luc; Hormozdiari, Farhad; Beaumont, Catherine; Zerjal, Tatiana; Vignal, Alain; Morisson, Mireille; Lagarrigue, Sandrine; Pitel, Frédérique

    2014-04-01

    Genomic imprinting is an epigenetic mechanism by which alleles of some specific genes are expressed in a parent-of-origin manner. It has been observed in mammals and marsupials, but not in birds. Until now, only a few genes orthologous to mammalian imprinted ones have been analyzed in chicken and did not demonstrate any evidence of imprinting in this species. However, several published observations such as imprinted-like QTL in poultry or reciprocal effects keep the question open. Our main objective was thus to screen the entire chicken genome for parental-allele-specific differential expression on whole embryonic transcriptomes, using high-throughput sequencing. To identify the parental origin of each observed haplotype, two chicken experimental populations were used, as inbred and as genetically distant as possible. Two families were produced from two reciprocal crosses. Transcripts from 20 embryos were sequenced using NGS technology, producing ∼200 Gb of sequences. This allowed the detection of 79 potentially imprinted SNPs, through an analysis method that we validated by detecting imprinting from mouse data already published. However, out of 23 candidates tested by pyrosequencing, none could be confirmed. These results come together, without a priori, with previous statements and phylogenetic considerations assessing the absence of genomic imprinting in chicken.

  20. Transcriptome-wide investigation of genomic imprinting in chicken

    PubMed Central

    Frésard, Laure; Leroux, Sophie; Servin, Bertrand; Gourichon, David; Dehais, Patrice; Cristobal, Magali San; Marsaud, Nathalie; Vignoles, Florence; Bed'hom, Bertrand; Coville, Jean-Luc; Hormozdiari, Farhad; Beaumont, Catherine; Zerjal, Tatiana; Vignal, Alain; Morisson, Mireille; Lagarrigue, Sandrine; Pitel, Frédérique

    2014-01-01

    Genomic imprinting is an epigenetic mechanism by which alleles of some specific genes are expressed in a parent-of-origin manner. It has been observed in mammals and marsupials, but not in birds. Until now, only a few genes orthologous to mammalian imprinted ones have been analyzed in chicken and did not demonstrate any evidence of imprinting in this species. However, several published observations such as imprinted-like QTL in poultry or reciprocal effects keep the question open. Our main objective was thus to screen the entire chicken genome for parental-allele-specific differential expression on whole embryonic transcriptomes, using high-throughput sequencing. To identify the parental origin of each observed haplotype, two chicken experimental populations were used, as inbred and as genetically distant as possible. Two families were produced from two reciprocal crosses. Transcripts from 20 embryos were sequenced using NGS technology, producing ∼200 Gb of sequences. This allowed the detection of 79 potentially imprinted SNPs, through an analysis method that we validated by detecting imprinting from mouse data already published. However, out of 23 candidates tested by pyrosequencing, none could be confirmed. These results come together, without a priori, with previous statements and phylogenetic considerations assessing the absence of genomic imprinting in chicken. PMID:24452801

  1. Molecularly Imprinted Membranes

    PubMed Central

    Trotta, Francesco; Biasizzo, Miriam; Caldera, Fabrizio

    2012-01-01

    Although the roots of molecularly imprinted polymers lie in the beginning of 1930s in the past century, they have had an exponential growth only 40–50 years later by the works of Wulff and especially by Mosbach. More recently, it was also proved that molecular imprinted membranes (i.e., polymer thin films) that show recognition properties at molecular level of the template molecule are used in their formation. Different procedures and potential application in separation processes and catalysis are reported. The influences of different parameters on the discrimination abilities are also discussed. PMID:24958291

  2. Molecularly imprinted membranes.

    PubMed

    Trotta, Francesco; Biasizzo, Miriam; Caldera, Fabrizio

    2012-07-19

    Although the roots of molecularly imprinted polymers lie in the beginning of 1930s in the past century, they have had an exponential growth only 40-50 years later by the works of Wulff and especially by Mosbach. More recently, it was also proved that molecular imprinted membranes (i.e., polymer thin films) that show recognition properties at molecular level of the template molecule are used in their formation. Different procedures and potential application in separation processes and catalysis are reported. The influences of different parameters on the discrimination abilities are also discussed.

  3. The correlation between relatives on the supposition of genomic imprinting.

    PubMed Central

    Spencer, Hamish G

    2002-01-01

    Standard genetic analyses assume that reciprocal heterozygotes are, on average, phenotypically identical. If a locus is subject to genomic imprinting, however, this assumption does not hold. We incorporate imprinting into the standard quantitative-genetic model for two alleles at a single locus, deriving expressions for the additive and dominance components of genetic variance, as well as measures of resemblance among relatives. We show that, in contrast to the case with Mendelian expression, the additive and dominance deviations are correlated. In principle, this correlation allows imprinting to be detected solely on the basis of different measures of familial resemblances, but in practice, the standard error of the estimate is likely to be too large for a test to have much statistical power. The effects of genomic imprinting will need to be incorporated into quantitative-genetic models of many traits, for example, those concerned with mammalian birthweight. PMID:12019254

  4. Mom Knows Best: Imprinted Control of Hematopoietic Stem Cell Quiescence.

    PubMed

    Serrano-Lopez, Juana; Cancelas, Jose A

    2016-02-04

    The mechanisms by which imprinted loci control activity of hematopoietic stem cells (HSCs) are not known. In this issue of Cell Stem Cell, Qian et al. (2016) demonstrate that non-coding RNAs expressed by the maternal-imprinted locus Dlk1-Gtl2 maintain HSC self-renewal through the inhibition of PI3K-mTOR signaling, mitochondrial biogenesis, and metabolic activity.

  5. Genomic imprinting in psoriasis and atopic dermatitis: A review.

    PubMed

    Nguyen, Catherine M; Liao, Wilson

    2015-11-01

    Genomic imprinting is a genetic process where only one allele of a particular gene is expressed in a parent-of-origin dependent manner. Epigenetic changes in the DNA, such as methylation or acetylation of histones, are primarily thought to be responsible for silencing of the imprinted allele. Recently, global CpG methylation changes have been identified in psoriatic skin in comparison to normal skin, particularly near genes known to be upregulated in psoriasis such as KYNU, OAS2, and SERPINB3. Furthermore, imprinting has been associated with multi-chromosomal human disease, including diabetes and multiple sclerosis. This paper is the first to review the clinical and genetic evidence that exists in the literature for the association between imprinting and general skin disorders, including atopic dermatitis and psoriatic disease. Atopy was found to have evidence of imprinting on chromosomes 6, 11, 14, and 13. The β subunit of the IgE receptor on chromosome 11q12-13 may be imprinted. Psoriatic disease may be related to imprinting effects on chromosome 6 for psoriasis and 16 for psoriatic arthritis.

  6. Clickable molecularly imprinted nanoparticles.

    PubMed

    Xu, Changgang; Ye, Lei

    2011-06-07

    Terminal alkynyl and azide groups are introduced on the surface of molecularly imprinted core-shell nanoparticles using precipitation polymerization. These clickable groups enable simple nanoparticle conjugation and surface modification under mild reaction conditions, opening new opportunities for nanoparticle-based assays and chemical sensing.

  7. Genomic imprinting and its relevance to congenital disease, infertility, molar pregnancy and induced pluripotent stem cell.

    PubMed

    Tomizawa, Shin-ichi; Sasaki, Hiroyuki

    2012-02-01

    Genomic imprinting is an epigenetic gene-marking phenomenon that occurs in the germline, whereby genes are expressed from only one of the two parental copies in embryos and adults. Imprinting is essential for normal mammalian development and its disruption can cause various developmental defects and diseases. The process of imprinting in the germline involves DNA methylation of the imprint control regions (ICRs), and resulting parental-specific methylation imprints are maintained in the zygote and act as the marks controlling imprinted gene expression. Recent studies in mice have revealed new factors involved in imprint establishment during gametogenesis and maintenance during early development. Clinical studies have identified cases of imprinting disorders where involvement of factors shared by multiple ICRs for establishment or maintenance is suspected. These include Beckwith-Wiedemann syndrome, transient neonatal diabetes, Silver-Russell syndrome and others. More severe disruptions can lead to recurrent molar pregnancy, miscarriage or infertility. Imprinting defects may also occur during assisted reproductive technology or cell reprogramming. In this review, we summarize our current knowledge on the mechanisms of imprint establishment and maintenance, and discuss the relationship with various human disorders.

  8. The evolution of genomic imprinting: costs, benefits and long-term consequences.

    PubMed

    Holman, Luke; Kokko, Hanna

    2014-08-01

    Genomic imprinting refers to a pattern of gene expression in which a specific parent's allele is either under-expressed or completely silenced. Imprinting is an evolutionary conundrum because it appears to incur the costs of diploidy (e.g. presenting a larger target than haploidy to mutations) while foregoing its benefits (protection from harmful recessive mutations). Here, we critically evaluate previously proposed evolutionary benefits of imprinting and suggest some additional ones. We discuss whether each benefit is capable of explaining both the origin and maintenance of imprinting, and examine how the different benefits interact. We then outline the many costs of imprinting. Simple models show that circulating deleterious recessives can prevent the initial spread of imprinting, even if imprinting would be evolutionarily stable if it could persist long enough to purge these. We also show that imprinting can raise or lower the mutation load, depending on the selective regime and the degree of dominance. We finish by discussing the population-level consequences of imprinting, which can be both positive and negative. Imprinting offers many insights into evolutionary conflict, the interaction between individual- and population-level fitness effects, and the 'gene's-eye view' of evolution.

  9. Angelman syndrome imprinting center encodes a transcriptional promoter.

    PubMed

    Lewis, Michael W; Brant, Jason O; Kramer, Joseph M; Moss, James I; Yang, Thomas P; Hansen, Peter J; Williams, R Stan; Resnick, James L

    2015-06-02

    Clusters of imprinted genes are often controlled by an imprinting center that is necessary for allele-specific gene expression and to reprogram parent-of-origin information between generations. An imprinted domain at 15q11-q13 is responsible for both Angelman syndrome (AS) and Prader-Willi syndrome (PWS), two clinically distinct neurodevelopmental disorders. Angelman syndrome arises from the lack of maternal contribution from the locus, whereas Prader-Willi syndrome results from the absence of paternally expressed genes. In some rare cases of PWS and AS, small deletions may lead to incorrect parent-of-origin allele identity. DNA sequences common to these deletions define a bipartite imprinting center for the AS-PWS locus. The PWS-smallest region of deletion overlap (SRO) element of the imprinting center activates expression of genes from the paternal allele. The AS-SRO element generates maternal allele identity by epigenetically inactivating the PWS-SRO in oocytes so that paternal genes are silenced on the future maternal allele. Here we have investigated functional activities of the AS-SRO, the element necessary for maternal allele identity. We find that, in humans, the AS-SRO is an oocyte-specific promoter that generates transcripts that transit the PWS-SRO. Similar upstream promoters were detected in bovine oocytes. This result is consistent with a model in which imprinting centers become DNA methylated and acquire maternal allele identity in oocytes in response to transiting transcription.

  10. Parents do matter: genomic imprinting and parental sex effects in neurological disorders.

    PubMed

    Chatkupt, S; Antonowicz, M; Johnson, W G

    1995-05-01

    Genomic imprinting is a recently recognized phenomenon of differential expression of genetic material depending upon whether the genetic material has come from the male or female parent. This process of differential phenotypic expression involves mammalian development both in the normal and abnormal situations, resulting in parental sex effects. However, some parental sex effects may be due to other mechanisms such as mitochondrial inheritance. In the following article, evidence for genomic imprinting in experimental animals and in diseases are summarized. Relevant human neurological disorders manifesting parental sex effects discussed here include myotonic dystrophy, Huntington's disease, fragile X syndrome, spinocerebellar ataxia type 1, and neurofibromatosis type 1 and 2. A possible mechanism of imprinting involves the processes of methylation imprint and replication imprint. The knowledge of imprinting is helpful in clinical practice particularly in the areas of genetic counseling, prenatal diagnosis, and possible future gene therapy.

  11. Different yet similar: evolution of imprinting in flowering plants and mammals

    PubMed Central

    2014-01-01

    Genomic imprinting refers to a form of epigenetic gene regulation whereby alleles are differentially expressed in a parent-of-origin-dependent manner. Imprinting evolved independently in flowering plants and in therian mammals in association with the elaboration of viviparity and a placental habit. Despite the striking differences in plant and animal reproduction, genomic imprinting shares multiple characteristics between them. In both groups, imprinted expression is controlled, at least in part, by DNA methylation and chromatin modifications in cis-regulatory regions, and many maternally and paternally expressed genes display complementary dosage-dependent effects during embryogenesis. This suggests that genomic imprinting evolved in response to similar selective pressures in flowering plants and mammals. Nevertheless, there are important differences between plant and animal imprinting. In particular, genomic imprinting has been shown to be more flexible and evolutionarily labile in plants. In mammals, imprinted genes are organized mainly in highly conserved clusters, whereas in plants they occur in isolation throughout the genome and are affected by local gene duplications. There is a large degree of intra- and inter-specific variation in imprinted gene expression in plants. These differences likely reflect the distinct life cycles and the different evolutionary dynamics that shape plant and animal genomes. PMID:25165562

  12. Different yet similar: evolution of imprinting in flowering plants and mammals.

    PubMed

    Pires, Nuno D; Grossniklaus, Ueli

    2014-01-01

    Genomic imprinting refers to a form of epigenetic gene regulation whereby alleles are differentially expressed in a parent-of-origin-dependent manner. Imprinting evolved independently in flowering plants and in therian mammals in association with the elaboration of viviparity and a placental habit. Despite the striking differences in plant and animal reproduction, genomic imprinting shares multiple characteristics between them. In both groups, imprinted expression is controlled, at least in part, by DNA methylation and chromatin modifications in cis-regulatory regions, and many maternally and paternally expressed genes display complementary dosage-dependent effects during embryogenesis. This suggests that genomic imprinting evolved in response to similar selective pressures in flowering plants and mammals. Nevertheless, there are important differences between plant and animal imprinting. In particular, genomic imprinting has been shown to be more flexible and evolutionarily labile in plants. In mammals, imprinted genes are organized mainly in highly conserved clusters, whereas in plants they occur in isolation throughout the genome and are affected by local gene duplications. There is a large degree of intra- and inter-specific variation in imprinted gene expression in plants. These differences likely reflect the distinct life cycles and the different evolutionary dynamics that shape plant and animal genomes.

  13. A model for genomic imprinting in the social brain: adults.

    PubMed

    Ubeda, Francisco; Gardner, Andy

    2011-02-01

    Genomic imprinting refers to genes that are silenced when inherited via sperm or via egg. The silencing of genes conditional upon their parental origin requires an evolutionary explanation. The most widely accepted theory for the evolution of genomic imprinting-the kinship theory-argues that conflict between maternally inherited and paternally inherited genes over phenotypes with asymmetric effects on matrilineal and patrilineal kin results in self-imposed silencing of one of the copies. This theory has been applied to imprinting of genes expressed in the placenta, and infant brain determining the allocation of parental resources being the source of conflict parental promiscuity. However, there is growing evidence that imprinted genes are expressed in the postinfant brain where parental promiscuity per se is no longer a source of conflict. Here, we advance the kinship theory by developing an evolutionary model of genomic imprinting in adults, driven by intragenomic conflict over allocation to parental versus communal care. We consider the role of sex differences in dispersal and variance in reproductive success as sources of conflict. We predict that, in hominids and birds, parental care will be expressed by maternally inherited genes. In nonhominid mammals, we predict more diversity, with some mammals showing the same pattern and other showing the reverse. We use the model to interpret experimental data on imprinted genes in the house mouse: specifically, paternally expressed Peg1 and Peg3 genes, underlying maternal care, and maternally expressed Gnas and paternally expressed Gnasxl genes, underlying communal care. We also use the model to relate ancestral demography to contemporary imprinting disorders of adults, in humans and other taxa.

  14. Exposure of mouse embryos to ethanol during preimplantation development: effect on DNA methylation in the h19 imprinting control region.

    PubMed

    Haycock, Philip C; Ramsay, Michéle

    2009-10-01

    In the present study, it was hypothesized that disruption of imprinting control in the H19/Igf2 domain may be a mechanism of ethanol-induced growth retardation-a key clinical feature of the fetal alcohol spectrum disorders (FASD). To test this prediction, genomic bisulphite sequencing was carried out on 473 bp of the H19 imprinting control region in DNA obtained from midgestation F(1) hybrid mouse embryos (C57BL/6 x Mus musculus castaneus) exposed to ethanol during preimplantation development. Although ethanol-exposed placentae and embryos were severely growth retarded in comparison with saline-treated controls, DNA methylation at paternal and maternal alleles was unaffected in embryos. However, paternal alleles were significantly less methylated in ethanol-treated placentae in comparison with saline-treated controls. Partial correlations suggested that the relationship between ethanol and placental weight partly depended on DNA methylation at a CCCTC-binding factor site on the paternal allele in placentae, suggesting a novel mechanism of ethanol-induced growth retardation. In contrast, partial correlations suggested that embryo growth retardation was independent of placental growth retardation. Relaxation of allele-specific DNA methylation in control placentae in comparison with control embryos was also observed, consistent with a model of imprinting in which 1) regulation of allele-specific DNA methylation in the placenta depends on a stochastic interplay between silencer and enhancer chromatin assembly factors and 2) imprinting control mechanisms in the embryo are more robust to environmental perturbations.

  15. All-atom structural models for complexes of insulin-like growth factors IGF1 and IGF2 with their cognate receptor.

    PubMed

    Vashisth, Harish; Abrams, Cameron F

    2010-07-16

    Type 1 insulin-like growth factor receptor (IGF1R) is a membrane-spanning glycoprotein of the insulin receptor family that has been implicated in a variety of cancers. The key questions related to molecular mechanisms governing ligand recognition by IGF1R remain unanswered, partly due to the lack of testable structural models of apo or ligand-bound receptor complexes. Using a homology model of the IGF1R ectodomain IGF1RDeltabeta, we present the first experimentally consistent all-atom structural models of IGF1/IGF1RDeltabeta and IGF2/IGF1RDeltabeta complexes. Our explicit-solvent molecular dynamics (MD) simulation of apo-IGF1RDeltabeta shows that it displays asymmetric flexibility mechanisms that result in one of two binding pockets accessible to growth factors IGF1 and IGF2, as demonstrated via an MD-assisted Monte Carlo docking procedure. Our MD-generated ensemble of structures of apo and IGF1-bound IGF1RDeltabeta agrees reasonably well with published small-angle X-ray scattering data. We observe simultaneous contacts of each growth factor with sites 1 and 2 of IGF1R, suggesting cross-linking of receptor subunits. Our models provide direct evidence in favor of suggested electrostatic complementarity between the C-domain (IGF1) and the cysteine-rich domain (IGF1R). Our IGF1/IGF1RDeltabeta model provides structural bases for the observation that a single IGF1 molecule binds to IGF1RDeltabeta at low concentrations in small-angle X-ray scattering studies. We also suggest new possible structural bases for differences in the affinities of insulin, IGF1, and IGF2 for their noncognate receptors.

  16. Genomic imprinting, methylation and parent-of-origin effects in reciprocal hybrid endosperm of castor bean.

    PubMed

    Xu, Wei; Dai, Mengyuan; Li, Fei; Liu, Aizhong

    2014-06-01

    Genomic imprinting often results in parent-of-origin specific differential expression of maternally and paternally inherited alleles. In plants, the triploid endosperm is where gene imprinting occurs most often, but aside from studies on Arabidopsis, little is known about gene imprinting in dicotyledons. In this study, we inspected genomic imprinting in castor bean (Ricinus communis) endosperm, which persists throughout seed development. After mapping out the polymorphic SNP loci between accessions ZB306 and ZB107, we generated deep sequencing RNA profiles of F1 hybrid seeds derived from reciprocal crosses. Using polymorphic SNP sites to quantify allele-specific expression levels, we identified 209 genes in reciprocal endosperms with potential parent-of-origin specific expression, including 200 maternally expressed genes and 9 paternally expressed genes. In total, 57 of the imprinted genes were validated via reverse transcriptase-polymerase chain reaction sequencing, and analysis of the genomic DNA methylation distribution between embryo and endosperm tissues showed significant hypomethylation in the endosperm and an enrichment of differentially methylated regions around the identified genes. Curiously, the expression of the imprinted genes was not tightly linked to DNA methylation. These results largely extended gene imprinting information existing in plants, providing potential directions for further research in gene imprinting.

  17. Genomic imprinting, methylation and parent-of-origin effects in reciprocal hybrid endosperm of castor bean

    PubMed Central

    Xu, Wei; Dai, Mengyuan; Li, Fei; Liu, Aizhong

    2014-01-01

    Genomic imprinting often results in parent-of-origin specific differential expression of maternally and paternally inherited alleles. In plants, the triploid endosperm is where gene imprinting occurs most often, but aside from studies on Arabidopsis, little is known about gene imprinting in dicotyledons. In this study, we inspected genomic imprinting in castor bean (Ricinus communis) endosperm, which persists throughout seed development. After mapping out the polymorphic SNP loci between accessions ZB306 and ZB107, we generated deep sequencing RNA profiles of F1 hybrid seeds derived from reciprocal crosses. Using polymorphic SNP sites to quantify allele-specific expression levels, we identified 209 genes in reciprocal endosperms with potential parent-of-origin specific expression, including 200 maternally expressed genes and 9 paternally expressed genes. In total, 57 of the imprinted genes were validated via reverse transcriptase-polymerase chain reaction sequencing, and analysis of the genomic DNA methylation distribution between embryo and endosperm tissues showed significant hypomethylation in the endosperm and an enrichment of differentially methylated regions around the identified genes. Curiously, the expression of the imprinted genes was not tightly linked to DNA methylation. These results largely extended gene imprinting information existing in plants, providing potential directions for further research in gene imprinting. PMID:24799438

  18. Conserved imprinting associated with unique epigenetic signatures in the Arabidopsis genus

    PubMed Central

    Klosinska, Maja; Picard, Colette L.; Gehring, Mary

    2017-01-01

    In plants, imprinted gene expression occurs in endosperm seed tissue and is sometimes associated with differential DNA methylation between maternal and paternal alleles1. Imprinting is theorized to have been selected for because of conflict between parental genomes in offspring2, but most studies of imprinting have been conducted in Arabidopsis thaliana, an inbred primarily self-fertilizing species that should have limited parental conflict. We examined embryo and endosperm allele-specific expression and DNA methylation genome-wide in the wild outcrossing species Arabidopsis lyrata. Here we show that the majority of A. lyrata imprinted genes also exhibit parentally-biased expression in A. thaliana, suggesting that there is evolutionary conservation in gene imprinting. Surprisingly, we discovered substantial interspecies differences in methylation features associated with paternally expressed imprinted genes (PEGs). Unlike in A. thaliana, the maternal allele of many A. lyrata PEGs was hypermethylated in the CHG context. Increased maternal allele CHG methylation was associated with increased expression bias in favor of the paternal allele. We propose that CHG methylation maintains or reinforces repression of maternal alleles of PEGs. These data suggest that while the genes subject to imprinting are largely conserved, there is flexibility in the epigenetic mechanisms employed between closely related species to maintain monoallelic expression. This supports the idea that imprinting of specific genes is a functional phenomenon, and not simply a byproduct of seed epigenomic reprogramming. PMID:27643534

  19. Coreceptor gene imprinting governs thymocyte lineage fate

    PubMed Central

    Adoro, Stanley; McCaughtry, Thomas; Erman, Batu; Alag, Amala; Van Laethem, François; Park, Jung-Hyun; Tai, Xuguang; Kimura, Motoko; Wang, Lie; Grinberg, Alex; Kubo, Masato; Bosselut, Remy; Love, Paul; Singer, Alfred

    2012-01-01

    Immature thymocytes are bipotential cells that are signalled during positive selection to become either helper- or cytotoxic-lineage T cells. By tracking expression of lineage determining transcription factors during positive selection, we now report that the Cd8 coreceptor gene locus co-opts any coreceptor protein encoded within it to induce thymocytes to express the cytotoxic-lineage factor Runx3 and to adopt the cytotoxic-lineage fate, findings we refer to as ‘coreceptor gene imprinting'. Specifically, encoding CD4 proteins in the endogenous Cd8 gene locus caused major histocompatibility complex class II-specific thymocytes to express Runx3 during positive selection and to differentiate into CD4+ cytotoxic-lineage T cells. Our findings further indicate that coreceptor gene imprinting derives from the dynamic regulation of specific cis Cd8 gene enhancer elements by positive selection signals in the thymus. Thus, for coreceptor-dependent thymocytes, lineage fate is determined by Cd4 and Cd8 coreceptor gene loci and not by the specificity of T-cell antigen receptor/coreceptor signalling. This study identifies coreceptor gene imprinting as a critical determinant of lineage fate determination in the thymus. PMID:22036949

  20. Genomic imprinting in disruptive spermatogenesis.

    PubMed

    Marques, Cristina Joana; Carvalho, Filipa; Sousa, Mário; Barros, Alberto

    2004-05-22

    The possibility of imprinting disease transmission by assisted reproductive technologies has been raised after births of children with Angelman's and Beckwith-Wiedemann's syndromes. To investigate whether imprinting defects were associated with disturbed spermatogenesis, we studied two oppositely imprinted genes in spermatozoan DNA from normozoospermic and oligozoospermic patients. In the mesodermal specific transcript gene (MEST), bisulphite genomic sequencing showed that maternal imprinting was correctly erased in all 123 patients. However, methylation of the H19 gene did not change in any of 27 normozoospermic individuals (0%, 95% CI 0-13%), compared with methylation changes in eight moderate (17%, 8-31%, p=0.026) and 15 severe (30%, 18-45%, p=0.002) oligozoospermic patients. Our data suggest an association between abnormal genomic imprinting and hypospermatogenesis, and that spermatozoa from oligozoospermic patients carry a raised risk of transmitting imprinting errors.

  1. Snx14 Regulates Neuronal Excitability, Promotes Synaptic Transmission, and Is Imprinted in the Brain of Mice

    PubMed Central

    Huang, Hsien-Sung; Yoon, Bong-June; Brooks, Sherian; Bakal, Robert; Berrios, Janet; Larsen, Rylan S.; Wallace, Michael L.; Han, Ji Eun; Chung, Eui Hwan; Zylka, Mark J.; Philpot, Benjamin D.

    2014-01-01

    Genomic imprinting describes an epigenetic process through which genes can be expressed in a parent-of-origin-specific manner. The monoallelic expression of imprinted genes renders them particularly susceptible to disease causing mutations. A large proportion of imprinted genes are expressed in the brain, but little is known about their functions. Indeed, it has proven difficult to identify cell type-specific imprinted genes due to the heterogeneity of cell types within the brain. Here we used laser capture microdissection of visual cortical neurons and found evidence that sorting nexin 14 (Snx14) is a neuronally imprinted gene in mice. SNX14 protein levels are high in the brain and progressively increase during neuronal development and maturation. Snx14 knockdown reduces intrinsic excitability and severely impairs both excitatory and inhibitory synaptic transmission. These data reveal a role for monoallelic Snx14 expression in maintaining normal neuronal excitability and synaptic transmission. PMID:24859318

  2. Genomic imprinting is a parental effect established in mammalian germ cells.

    PubMed

    Li, Xiajun

    2013-01-01

    Genomic imprinting is an epigenetic phenomenon in which either the paternal or the maternal allele of imprinted genes is expressed in somatic cells. It is unique to eutherian mammals, marsupials, and flowering plants. It is absolutely required for normal mammalian development. Dysregulation of genomic imprinting can cause a variety of human diseases. About 150 imprinted genes have been identified so far in mammals and many of them are clustered such that they are coregulated by a cis-acting imprinting control region, called the ICR. One hallmark of the ICR is that it contains a germ line-derived differentially methylated region that is methylated on the paternal chromosome or on the maternal chromosome. The DNA methylation imprint is reset in the germ line and differential methylation at an ICR is restored upon fertilization. The DNA methylation imprint is resistant to a genome-wide demethylation process in early embryos and is stably maintained in postimplantation embryos. Maintenance of the DNA methylation imprint is dependent on two distinct maternal effect genes (Zfp57 and PGC7/Stella). In germ cells, around midgestation, the DNA methylation imprint is erased and undergoes another round of the DNA methylation imprint cycle that includes erasure, resetting, restoration, and maintenance of differential DNA methylation.

  3. Solvent Immersion Imprint Lithography

    SciTech Connect

    Vasdekis, Andreas E.; Wilkins, Michael J.; Grate, Jay W.; Kelly, Ryan T.; Konopka, Allan; Xantheas, Sotiris S.; Chang, M. T.

    2014-06-21

    The mechanism of polymer disolution was explored for polymer microsystem prototyping, including microfluidics and optofluidics. Polymer films are immersed in a solvent, imprinted and finally brought into contact with a non-modified surface to permanently bond. The underlying polymer-solvent interactions were experimentally and theoretically investigated, and enabled rapid polymer microsystem prototyping. During imprinting, small molecule integration in the molded surfaces was feasible, a principle applied to oxygen sensing. Polystyrene (PS) was employed for microbiological studies at extreme environmental conditions. The thermophile anaerobe Clostridium Thermocellum was grown in PS pore-scale micromodels, revealing a double mean generation lifetime than under ideal culture conditions. Microsystem prototyping through directed polymer dissolution is simple and accessible, while simultaneous patterning, bonding, and surface/volume functionalization are possible in less than one minute.

  4. Metabolic imprinting in obesity.

    PubMed

    Sullivan, E L; Grove, K L

    2010-01-01

    Increasing evidence indicates that early metabolic programming contributes to escalating obesity rates in children and adults. Metabolic imprinting is involved in the establishment of set points for physiologic and metabolic responses in adulthood. Evidence from epidemiological studies and animal models indicates that maternal health and nutritional status during gestation and lactation have long-term effects on central and peripheral systems that regulate energy balance in the developing offspring. Perinatal nutrition also impacts susceptibility to developing metabolic disorders and plays a role in programming body weight set points. The states of maternal energy status and health that are implicated in predisposing offspring to increased risk of developing obesity include maternal overnutrition, diabetes, and undernutrition. This chapter discusses the evidence from epidemiologic studies and animal models that each of these states of maternal energy status results in metabolic imprinting of obesity in offspring. Also, the potential molecular mediators of metabolic imprinting of obesity by maternal energy status including glucose, insulin, leptin, inflammatory cytokines and epigenetic mechanisms are considered.

  5. Prader-Willi Syndrome: Obesity due to Genomic Imprinting

    PubMed Central

    Butler, Merlin G

    2011-01-01

    Prader-Willi syndrome (PWS) is a complex neurodevelopmental disorder due to errors in genomic imprinting with loss of imprinted genes that are paternally expressed from the chromosome 15q11-q13 region. Approximately 70% of individuals with PWS have a de novo deletion of the paternally derived 15q11-q13 region in which there are two subtypes (i.e., larger Type I or smaller Type II), maternal disomy 15 (both 15s from the mother) in about 25% of cases, and the remaining subjects have either defects in the imprinting center controlling the activity of imprinted genes or due to other chromosome 15 rearrangements. PWS is characterized by a particular facial appearance, infantile hypotonia, a poor suck and feeding difficulties, hypogonadism and hypogenitalism in both sexes, short stature and small hands and feet due to growth hormone deficiency, mild learning and behavioral problems (e.g., skin picking, temper tantrums) and hyperphagia leading to early childhood obesity. Obesity is a significant health problem, if uncontrolled. PWS is considered the most common known genetic cause of morbid obesity in children. The chromosome 15q11-q13 region contains approximately 100 genes and transcripts in which about 10 are imprinted and paternally expressed. This region can be divided into four groups: 1) a proximal non-imprinted region; 2) a PWS paternal-only expressed region containing protein-coding and non-coding genes; 3) an Angelman syndrome region containing maternally expressed genes and 4) a distal non-imprinted region. This review summarizes the current understanding of the genetic causes, the natural history and clinical presentation of individuals with PWS. PMID:22043168

  6. Cell Pluripotency Levels Associated with Imprinted Genes in Human

    PubMed Central

    Yuan, Liyun; Tang, Xiaoyan; Zhang, Binyan; Ding, Guohui

    2015-01-01

    Pluripotent stem cells are exhibited similarly in the morphology, gene expression, growth properties, and epigenetic modification with embryonic stem cells (ESCs). However, it is still controversial that the pluripotency of induced pluripotent stem cell (iPSC) is much inferior to ESC, and the differentiation capacity of iPSC and ESC can also be separated by transcriptome and epigenetics. miRNAs, which act in posttranscriptional regulation of gene expression and are involved in many basic cellular processes, may reveal the answer. In this paper, we focused on identifying the hidden relationship between miRNAs and imprinted genes in cell pluripotency. Total miRNA expression patterns in iPSC and ES cells were comprehensively analysed and linked with human imprinted genes, which show a global picture of their potential function in pluripotent level. A new CPA4-KLF14 region which locates in chromosomal homologous segments (CHSs) within mammals and include both imprinted genes and significantly expressed miRNAs was first identified. Molecular network analysis showed genes interacted with imprinted genes closely and enriched in modules such as cancer, cell death and survival, and tumor morphology. This imprinted region may provide a new look for those who are interested in cell pluripotency of hiPSCs and hESCs. PMID:26504487

  7. Cell Pluripotency Levels Associated with Imprinted Genes in Human.

    PubMed

    Yuan, Liyun; Tang, Xiaoyan; Zhang, Binyan; Ding, Guohui

    2015-01-01

    Pluripotent stem cells are exhibited similarly in the morphology, gene expression, growth properties, and epigenetic modification with embryonic stem cells (ESCs). However, it is still controversial that the pluripotency of induced pluripotent stem cell (iPSC) is much inferior to ESC, and the differentiation capacity of iPSC and ESC can also be separated by transcriptome and epigenetics. miRNAs, which act in posttranscriptional regulation of gene expression and are involved in many basic cellular processes, may reveal the answer. In this paper, we focused on identifying the hidden relationship between miRNAs and imprinted genes in cell pluripotency. Total miRNA expression patterns in iPSC and ES cells were comprehensively analysed and linked with human imprinted genes, which show a global picture of their potential function in pluripotent level. A new CPA4-KLF14 region which locates in chromosomal homologous segments (CHSs) within mammals and include both imprinted genes and significantly expressed miRNAs was first identified. Molecular network analysis showed genes interacted with imprinted genes closely and enriched in modules such as cancer, cell death and survival, and tumor morphology. This imprinted region may provide a new look for those who are interested in cell pluripotency of hiPSCs and hESCs.

  8. Genomic imprinting: a mammalian epigenetic discovery model.

    PubMed

    Barlow, Denise P

    2011-01-01

    Genomic imprinting is an epigenetic process leading to parental-specific expression of one to two percent of mammalian genes that offers one of the best model systems for a molecular analysis of epigenetic regulation in development and disease. In the twenty years since the first imprinted gene was identified, this model has had a significant impact on decoding epigenetic information in mammals. So far it has led to the discovery of long-range cis-acting control elements whose epigenetic state regulates small clusters of genes and of unusual macro noncoding RNAs (ncRNAs) that directly repress genes in cis, and critically, it has demonstrated that one biological role of DNA methylation is to allow expression of genes normally repressed by default. This review describes the progress in understanding how imprinted protein-coding genes are silenced; in particular, it focuses on the role of macro ncRNAs that have broad relevance as a potential new layer of regulatory information in the mammalian genome.

  9. A role for chromatin topology in imprinted domain regulation.

    PubMed

    MacDonald, William A; Sachani, Saqib S; White, Carlee R; Mann, Mellissa R W

    2016-02-01

    Recently, many advancements in genome-wide chromatin topology and nuclear architecture have unveiled the complex and hidden world of the nucleus, where chromatin is organized into discrete neighbourhoods with coordinated gene expression. This includes the active and inactive X chromosomes. Using X chromosome inactivation as a working model, we utilized publicly available datasets together with a literature review to gain insight into topologically associated domains, lamin-associated domains, nucleolar-associating domains, scaffold/matrix attachment regions, and nucleoporin-associated chromatin and their role in regulating monoallelic expression. Furthermore, we comprehensively review for the first time the role of chromatin topology and nuclear architecture in the regulation of genomic imprinting. We propose that chromatin topology and nuclear architecture are important regulatory mechanisms for directing gene expression within imprinted domains. Furthermore, we predict that dynamic changes in chromatin topology and nuclear architecture play roles in tissue-specific imprint domain regulation during early development and differentiation.

  10. Ftx is dispensable for imprinted X-chromosome inactivation in preimplantation mouse embryos

    PubMed Central

    Soma, Miki; Fujihara, Yoshitaka; Okabe, Masaru; Ishino, Fumitoshi; Kobayashi, Shin

    2014-01-01

    X-chromosome inactivation (XCI) equalizes gene expression between the sexes by inactivating one of the two X chromosomes in female mammals. Xist has been considered as a major cis-acting factor that inactivates the paternally derived X chromosome (Xp) in preimplantation mouse embryos (imprinted XCI). Ftx has been proposed as a positive regulator of Xist. However, the physiological role of Ftx in female animals has never been studied. We recently reported that Ftx is located in the cis-acting regulatory region of the imprinted XCI and expressed from the inactive Xp, suggesting a role in the imprinted XCI mechanism. Here we examined the effects on imprinted XCI using targeted deletion of Ftx. Disruption of Ftx did not affect the survival of female embryos or expression of Xist and other X-linked genes in the preimplantation female embryos. Our results indicate that Ftx is dispensable for imprinted XCI in preimplantation embryos. PMID:24899465

  11. Maternal control of nutrient allocation in plant seeds by genomic imprinting.

    PubMed

    Costa, Liliana M; Yuan, Jing; Rouster, Jacques; Paul, Wyatt; Dickinson, Hugh; Gutierrez-Marcos, Jose F

    2012-01-24

    Imprinted genes are commonly expressed in mammalian placentas and in plant seed endosperms, where they exhibit preferential uniparental allelic expression. In mammals, imprinted genes directly regulate placental function and nutrient distribution from mother to fetus; however, none of the >60 imprinted genes thus far reported in plants have been demonstrated to play an equivalent role in regulating the flow of resources to the embryo. Here we show that imprinted Maternally expressed gene1 (Meg1) in maize is both necessary and sufficient for the establishment and differentiation of the endosperm nutrient transfer cells located at the mother:seed interface. Consistent with these findings, Meg1 also regulates maternal nutrient uptake, sucrose partitioning, and seed biomass yield. In addition, we generated an imprinted and nonimprinted synthetic Meg1 ((syn)Meg1) dosage series whereby increased dosage and absence of imprinting both resulted in an unequal investment of maternal resources into the endosperm. These findings highlight dosage regulation by genomic imprinting as being critical for maintaining a balanced distribution of maternal nutrients to filial tissues in plants, as in mammals. However, unlike in mammals, Meg1 is a maternally expressed imprinted gene that surprisingly acts to promote rather than restrict nutrient allocation to the offspring.

  12. Molecular cloning, bioinformatics analysis and expression of insulin-like growth factor 2 from Tianzhu white yak, Bos grunniens.

    PubMed

    Zhang, Quanwei; Gong, Jishang; Wang, Xueying; Wu, Xiaohu; Li, Yalan; Ma, Youji; Zhang, Yong; Zhao, Xingxu

    2014-01-03

    The IGF family is essential for normal embryonic and postnatal development and plays important roles in the immune system, myogenesis, bone metabolism and other physiological functions, which makes the study of its structure and biological characteristics important. Tianzhu white yak (Bos grunniens) domesticated under alpine hypoxia environments, is well adapted to survive and grow against severe hypoxia and cold temperatures for extended periods. In this study, a full coding sequence of the IGF2 gene of Tianzhu white yak was amplified by reverse transcription PCR and rapid-amplification of cDNA ends (RACE) for the first time. The cDNA sequence revealed an open reading frame of 450 nucleotides, encoding a protein with 179 amino acids. Its expression in different tissues was also studied by Real time PCR. Phylogenetic tree analysis indicated that yak IGF2 was similar to Bos taurus, and 3D structure showed high similarity with the human IGF2. The putative full CDS of yak IGF2 was amplified by PCR in five tissues, and cDNA sequence analysis showed high homology to bovine IGF2. Moreover the super secondary structure prediction showed a similar 3D structure with human IGF2. Its conservation in sequence and structure has facilitated research on IGF2 and its physiological function in yak.

  13. Genomic imprinting, action, and interaction of maternal and fetal genomes

    PubMed Central

    Keverne, Eric B.

    2015-01-01

    Mammalian viviparity (intrauterine development of the fetus) introduced a new dimension to brain development, with the fetal hypothalamus and fetal placenta developing at a time when the fetal placenta engages hypothalamic structures of the maternal generation. Such transgenerational interactions provide a basis for ensuring optimal maternalism in the next generation. This success has depended on genomic imprinting and a biased role of the matriline. Maternal methylation imprints determine parent of origin expression of genes fundamental to both placental and hypothalamic development. The matriline takes a further leading role for transgenerational reprogramming of these imprints. Developmental errors are minimized by the tight control that imprinted genes have on regulation of downstream evolutionary expanded gene families important for placental and hypothalamic development. Imprinted genes themselves have undergone purifying selection, providing a framework of stability for in utero development with most growth variance occurring postnatally. Mothers, not fathers, take the lead in the endocrinological and behavior adaptations that nurture, feed, and protect the infant. In utero coadaptive development of the placenta and hypothalamus has thus required a concomitant development to ensure male masculinization. Only placental male mammals evolved the sex determining SRY, which activates Sox9 for testes formation. SRY is a hybrid gene of Dgcr8 expressed in the developing placenta and Sox3 expressed in hypothalamic development. This hybridization of genes that take their origin from the placenta and hypothalamus has enabled critical in utero timing for the development of fetal Leydig cells, and hence testosterone production for hypothalamic masculinization. PMID:25404322

  14. A model for genomic imprinting in the social brain: juveniles.

    PubMed

    Ubeda, Francisco; Gardner, Andy

    2010-09-01

    What are imprinted genes doing in the adult brain? Genomic imprinting is when a gene's expression depends upon parent of origin. According to the prevailing view, the "kinship theory" of genomic imprinting, this effect is driven by evolutionary conflicts between genes inherited via sperm versus egg. This theory emphasizes conflicts over the allocation of maternal resources, and focuses upon genes that are expressed in the placenta and infant brain. However, there is growing evidence that imprinted genes are also expressed in the juvenile and adult brain, after cessation of parental care. These genes have recently been suggested to underpin neurological disorders of the social brain such as psychosis and autism. Here we advance the kinship theory by developing an evolutionary model of genomic imprinting for social behavior beyond the nuclear family. We consider the role of demography and mating system, emphasizing the importance of sex differences in dispersal and variance in reproductive success. We predict that, in hominids and birds, altruism will be promoted by paternally inherited genes and egoism will be promoted by maternally inherited genes. In nonhominid mammals we predict more diversity, with some mammals showing the same pattern and other showing the reverse. We discuss the implications for the evolution of psychotic and autistic spectrum disorders in human populations with different social structures.

  15. Domain regulation of imprinting cluster in Kip2/Lit1 subdomain on mouse chromosome 7F4/F5: large-scale DNA methylation analysis reveals that DMR-Lit1 is a putative imprinting control region.

    PubMed

    Yatsuki, Hitomi; Joh, Keiichiro; Higashimoto, Ken; Soejima, Hidenobu; Arai, Yuji; Wang, Youdong; Hatada, Izuho; Obata, Yayoi; Morisaki, Hiroko; Zhang, Zhongming; Nakagawachi, Tetsuji; Satoh, Yuji; Mukai, Tsunehiro

    2002-12-01

    Mouse chromosome 7F4/F5, where the imprinting domain is located, is syntenic to human 11p15.5, the locus for Beckwith-Wiedemann syndrome. The domain is thought to consist of the two subdomains Kip2 (p57(kip2))/Lit1 and Igf2/H19. Because DNA methylation is believed to be a key factor in genomic imprinting, we performed large-scale DNA methylation analysis to identify the cis-element crucial for the regulation of the Kip2/Lit1 subdomain. Ten CpG islands (CGIs) were found, and these were located at the promoter sites, upstream of genes, and within intergenic regions. Bisulphite sequencing revealed that CGIs 4, 5, 8, and 10 were differentially methylated regions (DMRs). CGIs 4, 5, and 10 were methylated paternally in somatic tissues but not in germ cells. CGI8 was methylated in oocyte and maternally in somatic tissues during development. Parental-specific DNase I hypersensitive sites (HSSs) were found near CGI8. These data indicate that CGI8, called DMR-Lit1, is not only the region for gametic methylation but might also be the imprinting control region (ICR) of the subdomain.

  16. Establishment of paternal genomic imprinting in mouse prospermatogonia analyzed by nuclear transfer.

    PubMed

    Kamimura, Satoshi; Hatanaka, Yuki; Hirasawa, Ryutaro; Matsumoto, Kazuya; Oikawa, Mami; Lee, Jiyoung; Matoba, Shogo; Mizutani, Eiji; Ogonuki, Narumi; Inoue, Kimiko; Kohda, Takashi; Ishino, Fumitoshi; Ogura, Atsuo

    2014-11-01

    In mice, the establishment of paternal genomic imprinting in male germ cells starts at midgestation, as suggested by DNA methylation analyses of differentially methylated regions (DMRs). However, this information is based on averages from mixed populations of germ cells, and the DNA methylation pattern might not always provide a full representation of imprinting status. To obtain more detailed information on the establishment of paternal imprinting, single prospermatogonia at Embryonic Days 15.5 (E15.5), E16.5, and E17.5 and at Day 0.5 after birth were cloned using nuclear transfer; previous reports suggested that cloned embryos reflected the donor's genomic imprinting status. Then, the resultant fetuses (E9.5) were analyzed for the DNA methylation pattern of three paternal DMRs (IG-DMR, H19 DMR, and Rasgrf1 DMR) and the expression pattern of imprinted genes therein. The overall data indicated that establishment of genomic imprinting in all paternally imprinted regions was completed by E17.5, following a short intermediate period at E16.5. Furthermore, comparison between the methylation status of DMRs and the expression profiles of imprinted genes suggested that methylation of the IG-DMR, but not the H19 DMR, solely governed the control of its imprinted gene cluster. The Rasgrf1 DMR seemed to be imprinted later than the other two genes. We also found that the methylation status of the Gtl2 DMR, the secondary DMR that acquires DNA methylation after fertilization, was likely to follow the methylation status of the upstream IG-DMR. Thus, the systematic analyses of prospermatogonium-derived embryos provided additional important information on the establishment of paternal imprinting.

  17. Xist imprinting is promoted by the hemizygous (unpaired) state in the male germ line

    PubMed Central

    Sun, Sha; Payer, Bernhard; Namekawa, Satoshi; An, Jee Young; Press, William; Catalan-Dibene, Jovani; Sunwoo, Hongjae; Lee, Jeannie T.

    2015-01-01

    The long noncoding X-inactivation–specific transcript (Xist gene) is responsible for mammalian X-chromosome dosage compensation between the sexes, the process by which one of the two X chromosomes is inactivated in the female soma. Xist is essential for both the random and imprinted forms of X-chromosome inactivation. In the imprinted form, Xist is paternally marked to be expressed in female embryos. To investigate the mechanism of Xist imprinting, we introduce Xist transgenes (Tg) into the male germ line. Although ectopic high-level Xist expression on autosomes can be compatible with viability, transgenic animals demonstrate reduced fitness, subfertility, defective meiotic pairing, and other germ-cell abnormalities. In the progeny, paternal-specific expression is recapitulated by the 200-kb Xist Tg. However, Xist imprinting occurs efficiently only when it is in an unpaired or unpartnered state during male meiosis. When transmitted from a hemizygous father (+/Tg), the Xist Tg demonstrates paternal-specific expression in the early embryo. When transmitted by a homozygous father (Tg/Tg), the Tg fails to show imprinted expression. Thus, Xist imprinting is directed by sequences within a 200-kb X-linked region, and the hemizygous (unpaired) state of the Xist region promotes its imprinting in the male germ line. PMID:26489649

  18. Programmable imprint lithography template

    DOEpatents

    Cardinale, Gregory F.; Talin, Albert A.

    2006-10-31

    A template for imprint lithography (IL) that reduces significantly template production costs by allowing the same template to be re-used for several technology generations. The template is composed of an array of spaced-apart moveable and individually addressable rods or plungers. Thus, the template can be configured to provide a desired pattern by programming the array of plungers such that certain of the plungers are in an "up" or actuated configuration. This arrangement of "up" and "down" plungers forms a pattern composed of protruding and recessed features which can then be impressed onto a polymer film coated substrate by applying a pressure to the template impressing the programmed configuration into the polymer film. The pattern impressed into the polymer film will be reproduced on the substrate by subsequent processing.

  19. Manganese uptake of imprinted polymers

    SciTech Connect

    Susanna Ventura

    2015-09-30

    Batch tests of manganese imprinted polymers of variable composition to assess their ability to extract lithium and manganese from synthetic brines at T=45C . Data on manganese uptake for two consecutive cycles are included.

  20. Imprinting defects on human chromosome 15.

    PubMed

    Horsthemke, B; Buiting, K

    2006-01-01

    The Prader-Willi syndrome (PWS) and Angelman syndrome (AS) are two distinct neurogenetic diseases that are caused by the loss of function of imprinted genes on the proximal long arm of human chromosome 15. In a few percent of patients with PWS and AS, the disease is due to aberrant imprinting and gene silencing. In patients with PWS and an imprinting defect, the paternal chromosome carries a maternal imprint. In patients with AS and an imprinting defect, the maternal chromosome carries a paternal imprint. Imprinting defects offer a unique opportunity to identify some of the factors and mechanisms involved in imprint erasure, resetting and maintenance. In approximately 10% of cases the imprinting defects are caused by a microdeletion affecting the 5' end of the SNURF-SNRPN locus. These deletions define the 15q imprinting center (IC), which regulates imprinting in the whole domain. These findings have been confirmed and extended in knock-out and transgenic mice. In the majority of patients with an imprinting defect, the incorrect imprint has arisen without a DNA sequence change, possibly as the result of stochastic errors of the imprinting process or the effect of exogenous factors.

  1. The role of genomic imprinting in human developmental disorders: lessons from Prader-Willi syndrome.

    PubMed

    Hanel, M L; Wevrick, R

    2001-03-01

    Normal human development involves a delicate interplay of gene expression in specific tissues at narrow windows of time. Temporally and spatially regulated gene expression is controlled both by gene-specific factors and chromatin-specific factors. Genomic imprinting is the expression of specific genes primarily from only one allele at particular times during development, and is one mechanism implicated in the intricate control of gene expression. Two human genetic disorders, Prader-Willi syndrome (PWS, MIM 176270) and Angelman syndrome (AS, MIM 105830), result from rearrangements of chromosome 15q11-q13, an imprinted region of the human genome. Despite their rarity, disorders such as PWS and AS can give focused insight into the role of genomic imprinting and imprinted genes in human development.

  2. Detection of imprinting mutations in Angelman syndrome using a probe for exon {alpha} of SNRPN

    SciTech Connect

    Beuten, J.; Sutcliffe, J.S.; Casey, B.M.

    1996-05-17

    Prader-Willi syndrome (PWS) and Angelman syndrome (AS) are distinct clinical disorders resulting from deficiency of paternal (PWS) or maternal (AS) expression of imprinted genes within chromosome 15q11-q13. 15 refs., 1 fig.

  3. Molecular imprinting: perspectives and applications.

    PubMed

    Chen, Lingxin; Wang, Xiaoyan; Lu, Wenhui; Wu, Xiaqing; Li, Jinhua

    2016-04-21

    Molecular imprinting technology (MIT), often described as a method of making a molecular lock to match a molecular key, is a technique for the creation of molecularly imprinted polymers (MIPs) with tailor-made binding sites complementary to the template molecules in shape, size and functional groups. Owing to their unique features of structure predictability, recognition specificity and application universality, MIPs have found a wide range of applications in various fields. Herein, we propose to comprehensively review the recent advances in molecular imprinting including versatile perspectives and applications, concerning novel preparation technologies and strategies of MIT, and highlight the applications of MIPs. The fundamentals of MIPs involving essential elements, preparation procedures and characterization methods are briefly outlined. Smart MIT for MIPs is especially highlighted including ingenious MIT (surface imprinting, nanoimprinting, etc.), special strategies of MIT (dummy imprinting, segment imprinting, etc.) and stimuli-responsive MIT (single/dual/multi-responsive technology). By virtue of smart MIT, new formatted MIPs gain popularity for versatile applications, including sample pretreatment/chromatographic separation (solid phase extraction, monolithic column chromatography, etc.) and chemical/biological sensing (electrochemical sensing, fluorescence sensing, etc.). Finally, we propose the remaining challenges and future perspectives to accelerate the development of MIT, and to utilize it for further developing versatile MIPs with a wide range of applications (650 references).

  4. Synthesis of magnetic cytosine-imprinted chitosan nanoparticles

    NASA Astrophysics Data System (ADS)

    Lee, Mei-Hwa; Ahluwalia, Arti; Chen, Jian-Zhou; Shih, Neng-Lang; Lin, Hung-Yin

    2017-02-01

    Molecularly imprinted polymer nanoparticles incorporating magnetic nanoparticles (MNPs) have been investigated for their selective adsorption properties. Here we describe the synthesis and characterization of magnetic cytosine-imprinted chitosan nanoparticles (CIPs) for gene delivery. In particular, CIPs carrying the mammalian expression plasmid of enhanced green fluorescent protein were prepared by the co-precipitation of MNPs, chitosan and a template nucleobase (cytosine). The results show that the selective reabsorption of cytosine to magnetic CIPs was at least double that of non-imprinted polymers and other nucleobases (such as adenine and thymine). The gene carrier CIPs were used for the transfection of human embryonic kidney 293 cells showing dramatic increase their efficiency with that of conventional chitosan nanoparticles. Furthermore, the gene carrier magnetic CIPs also exhibit low toxicity compared to that of commercially available cationic lipids.

  5. Genomic imprinting: the emergence of an epigenetic paradigm.

    PubMed

    Ferguson-Smith, Anne C

    2011-07-18

    The emerging awareness of the contribution of epigenetic processes to genome function in health and disease is underpinned by decades of research in model systems. In particular, many principles of the epigenetic control of genome function have been uncovered by studies of genomic imprinting. The phenomenon of genomic imprinting, which results in some genes being expressed in a parental--origin-specific manner, is essential for normal mammalian growth and development and exemplifies the regulatory influences of DNA methylation, chromatin structure and non-coding RNA. Setting seminal discoveries in this field alongside recent progress and remaining questions shows how the study of imprinting continues to enhance our understanding of the epigenetic control of genome function in other contexts.

  6. Synthesis of magnetic cytosine-imprinted chitosan nanoparticles.

    PubMed

    Lee, Mei-Hwa; Ahluwalia, Arti; Chen, Jian-Zhou; Shih, Neng-Lang; Lin, Hung-Yin

    2017-02-24

    Molecularly imprinted polymer nanoparticles incorporating magnetic nanoparticles (MNPs) have been investigated for their selective adsorption properties. Here we describe the synthesis and characterization of magnetic cytosine-imprinted chitosan nanoparticles (CIPs) for gene delivery. In particular, CIPs carrying the mammalian expression plasmid of enhanced green fluorescent protein were prepared by the co-precipitation of MNPs, chitosan and a template nucleobase (cytosine). The results show that the selective reabsorption of cytosine to magnetic CIPs was at least double that of non-imprinted polymers and other nucleobases (such as adenine and thymine). The gene carrier CIPs were used for the transfection of human embryonic kidney 293 cells showing dramatic increase their efficiency with that of conventional chitosan nanoparticles. Furthermore, the gene carrier magnetic CIPs also exhibit low toxicity compared to that of commercially available cationic lipids.

  7. Genomic imprinting effects in a compromised in utero environment: implications for a healthy pregnancy.

    PubMed

    Lim, A L; Ferguson-Smith, A C

    2010-04-01

    Genomic imprinting in gametogenesis marks a subset of mammalian genes for parent-of-origin-dependent monoallelic expression in the offspring. In mice, the identification and manipulation of individual imprinted genes has shown that the diverse products of these genes are largely devoted to controlling pre- and postnatal growth. Human syndromes with parental origin effects have been characterized both at the phenotypic and genotypic levels, allowing further elucidation of the function and regulation of imprinted genes. Evidence suggests that a compromised in utero environment influences fetal growth through the modulation of epigenetic states. However it is not known whether imprinted genes, by their nature, might be more or less susceptible to such environmental influences. Here we review the progress made in addressing the influence of a compromised in utero environment on the behavior of imprinted genes. We also examine whether these environmental influences may have an impact on the later development of human disease.

  8. Genomic Inprinting of the M6P/IGF2 Receptor: A Novel Breast Cancer Susceptibility Mechanism

    DTIC Science & Technology

    2001-07-01

    Nakayama • Yutaka Satou • Nori Satoh Isolation and characterization of genes that are expressed during Ciona intestinalis metamorphosis Received: 6...phosis in Ciona intestinalis . One of the tnes, Ci-metal, that a. initiated at the moment of settlement. According encodes a polypeptide with a putative...very Keywords Ascidians . etamorphosis .Genes. short p riod of time; the tail resorption of Ciona , for Cell signaling • Cell r arrangement example, is

  9. Expression profile, clinical significance, and biological function of insulin-like growth factor 2 messenger RNA-binding proteins in non-small cell lung cancer.

    PubMed

    Shi, Run; Yu, Xinnian; Wang, Yajing; Sun, Jing; Sun, Qi; Xia, Wenjie; Dong, Gaochao; Wang, Anpeng; Gao, Zhaojia; Jiang, Feng; Xu, Lin

    2017-04-01

    Insulin-like growth factor 2 messenger RNA-binding proteins have been described to associate with malignant process in many cancers. However, the role of insulin-like growth factor 2 messenger RNA-binding protein family has not been thoroughly elucidated in non-small cell lung cancer. This study was to investigate the expression profile, clinical significance, and biological function of insulin-like growth factor 2 messenger RNA-binding proteins family in non-small cell lung cancer. The expression levels of IGF2BP1-IGF2BP3 in tumor and adjacent normal tissues were determined, and association with clinicopathological features and overall survival was investigated by analyzing The Cancer Genome Atlas lung cancer database. Proliferation, migration, invasion assays, and flow-cytometry analysis were used to investigate the biological function in vitro. Insulin-like growth factor 2 messenger RNA-binding protein expression levels were significantly increased in non-small cell lung cancer compared to adjacent normal lung tissues. Chi-square test indicated that IGF2BP1 and IGF2BP3 expressions correlated with some meaningful clinical characteristics in non-small cell lung cancer. Kaplan-Meier analysis showed that high-level expression of IGF2BP1 or IGF2BP3 predicted poor overall survival in lung adenocarcinoma patients. Multivariate regression analysis showed that high level of IGF2BP3 was an independent risk factor for poor prognosis in lung adenocarcinoma patients (hazard ratio = 1.616, p = 0.017). In vitro, knockdown of IGF2BP3 inhibited lung adenocarcinoma cell proliferation by inducing cell cycle arrest and apoptosis, and undermined abilities of migration and invasion, and overexpression of IGF2BP3 could promote malignant phenotypes in lung adenocarcinoma cells. Our study revealed that expression of insulin-like growth factor 2 messenger RNA-binding proteins was widely upregulated and correlated with some certain clinicopathological features in non-small cell

  10. Bayesian mapping of genome-wide epistatic imprinted loci for quantitative traits.

    PubMed

    Li, Shize; Wang, Xin; Li, Jiahan; Yang, Tianfu; Min, Lingjiang; Liu, Yang; Lin, Min; Yang, Runqing

    2012-05-01

    Genomic imprinting, an epigenetic phenomenon of parent-of-origin-specific gene expression, has been widely observed in plants, animals, and humans. To detect imprinting genes influencing quantitative traits, the least squares and maximum likelihood approaches for fitting a single quantitative trait locus (QTL) and Bayesian methods for simultaneously modeling multiple QTL have been adopted, respectively, in various studies. However, most of these studies have only estimated imprinting main effects and thus ignored imprinting epistatic effects. In the presence of extremely complex genomic imprinting architectures, we introduce a Bayesian model selection method to analyze the multiple interacting imprinted QTL (iQTL) model. This approach will greatly enhance the computational efficiency through setting the upper bound of the number of QTLs and performing selective sampling for QTL parameters. The imprinting types of detected main-effect QTLs can be estimated from the Bayes factor statistic formulated by the posterior probabilities for the genetic effects being compared. The performance of the proposed method is demonstrated by several simulation experiments. Moreover, this method is applied to dissect the imprinting genetic architecture for body weight in mouse and fruit weight in tomato. Matlab code for implementing this approach will be available from the authors upon request.

  11. A Novel Imprinted Gene NUWA Controls Mitochondrial Function in Early Seed Development in Arabidopsis

    PubMed Central

    He, Shan; Sun, Yan; Zhang, Xiangyu; Zhao, Peng; Sun, Mengxiang; Liu, Jingjing; Qian, Weiqiang; Gu, Hongya; Qu, Li-Jia

    2017-01-01

    Imprinted genes display biased expression of paternal and maternal alleles and are only found in mammals and flowering plants. Compared to several hundred imprinted genes that are functionally characterized in mammals, very few imprinted genes were confirmed in plants and even fewer of them have been functionally investigated. Here, we report a new imprinted gene, NUWA, in plants. NUWA is an essential gene, because loss of its function resulted in reduced transmission through the female gametophyte and defective cell/nuclear proliferation in early Arabidopsis embryo and endosperm. NUWA is a maternally expressed imprinted gene, as only the maternal allele of NUWA is transcribed and translated from gametogenesis to the 16-cell globular embryo stage after fertilization, and the de novo transcription of the maternal allele of NUWA starts from the zygote stage. Different from other identified plant imprinted genes whose encoded proteins are mostly localized to the nucleus, the NUWA protein was localized to the mitochondria and was essential for mitochondria function. Our work uncovers a novel imprinted gene of a previously unidentified type, namely, a maternal-specific expressed nuclear gene with its encoded protein localizing to and controlling the function of the maternally inherited mitochondria. This reveals a unique mechanism of maternal control of the mitochondria and adds an extra layer of complexity to the regulation of nucleus-organelle coordination during early plant development. PMID:28095407

  12. Is there a genomically imprinted social brain?

    PubMed

    Curley, James P

    2011-09-01

    Imprinted genes (IGs) are expressed or silenced according to their parent-of-origin. These genes are known to play a role in regulating offspring growth, development and infant behaviors such as suckling and ultrasonic calls. In adults, neurally expressed IGs coordinate several behaviors including maternal care, sex, feeding, emotionality, and cognition. However, despite evidence from human psychiatric disorders and evolutionary theory that maternally and paternally expressed genes should also regulate social behavior, little empirical data from mouse research exists. This paper discusses data from a recent study (Garfield et al., 2011) that the IG Grb10 governs unique aspects of mouse social behavior and interprets the relevance of these findings for the future of this field.

  13. Dormancy-specific imprinting underlies maternal inheritance of seed dormancy in Arabidopsis thaliana

    PubMed Central

    Piskurewicz, Urszula; Iwasaki, Mayumi; Susaki, Daichi; Megies, Christian; Kinoshita, Tetsu; Lopez-Molina, Luis

    2016-01-01

    Mature seed dormancy is a vital plant trait that prevents germination out of season. In Arabidopsis, the trait can be maternally regulated but the underlying mechanisms sustaining this regulation, its general occurrence and its biological significance among accessions are poorly understood. Upon seed imbibition, the endosperm is essential to repress the germination of dormant seeds. Investigation of genomic imprinting in the mature seed endosperm led us to identify a novel set of imprinted genes that are expressed upon seed imbibition. Remarkably, programs of imprinted gene expression are adapted according to the dormancy status of the seed. We provide direct evidence that imprinted genes play a role in regulating germination processes and that preferential maternal allelic expression can implement maternal inheritance of seed dormancy levels. DOI: http://dx.doi.org/10.7554/eLife.19573.001 PMID:28005006

  14. Molecular mechanisms of memory in imprinting

    PubMed Central

    Solomonia, Revaz O.; McCabe, Brian J.

    2015-01-01

    Converging evidence implicates the intermediate and medial mesopallium (IMM) of the domestic chick forebrain in memory for a visual imprinting stimulus. During and after imprinting training, neuronal responsiveness in the IMM to the familiar stimulus exhibits a distinct temporal profile, suggesting several memory phases. We discuss the temporal progression of learning-related biochemical changes in the IMM, relative to the start of this electrophysiological profile. c-fos gene expression increases <15 min after training onset, followed by a learning-related increase in Fos expression, in neurons immunopositive for GABA, taurine and parvalbumin (not calbindin). Approximately simultaneously or shortly after, there are increases in phosphorylation level of glutamate (AMPA) receptor subunits and in releasable neurotransmitter pools of GABA and taurine. Later, the mean area of spine synapse post-synaptic densities, N-methyl-d-aspartate receptor number and phosphorylation level of further synaptic proteins are elevated. After ∼15 h, learning-related changes in amounts of several synaptic proteins are observed. The results indicate progression from transient/labile to trophic synaptic modification, culminating in stable recognition memory. PMID:25280906

  15. Allele-specific DNA methylation: beyond imprinting.

    PubMed

    Tycko, Benjamin

    2010-10-15

    Allele-specific DNA methylation (ASM) and allele-specific gene expression (ASE) have long been studied in genomic imprinting and X chromosome inactivation. But these types of allelic asymmetries, along with allele-specific transcription factor binding (ASTF), have turned out to be far more pervasive-affecting many non-imprinted autosomal genes in normal human tissues. ASM, ASE and ASTF have now been mapped genome-wide by microarray-based methods and NextGen sequencing. Multiple studies agree that all three types of allelic asymmetries, as well as the related phenomena of expression and methylation quantitative trait loci, are mostly accounted for by cis-acting regulatory polymorphisms. The precise mechanisms by which this occurs are not yet understood, but there are some testable hypotheses and already a few direct clues. Future challenges include achieving higher resolution maps to locate the epicenters of cis-regulated ASM, using this information to test mechanistic models, and applying genome-wide maps of ASE/ASM/ASTF to pinpoint functional regulatory polymorphisms influencing disease susceptibility.

  16. Benjamin Franklin's Medical Imprints

    PubMed Central

    Cantu, Jane Quale

    1965-01-01

    The printing house of Benjamin Franklin produced several works of a medical nature in Colonial America at a time when very few medical treatises were being written or printed. Benjamin Franklin was also indirectly responsible for the founding of the first medical library in this country. For these reasons he was, in addition to his many other talents, an early contributor to American medical literature. Included in this bibliography are all the known medical books, pamphlets, and broadsides in English with Benjamin Franklin's name in the imprint, issued in America. These eighteen titles span the years 1732 to 1765 and are presented chronologically with indications of their relation to the practice and practitioners of Colonial medicine. Benjamin Franklin's press produced as wide a variety of contributions as did his versatile life, and the early history of medicine in this country bears the influence of both. I am pleased with your scheme of a Medical Library at the Hospital, and I fancy I can procure you some donations among my medical friends here, if you will send me a catalogue of what books you already have. Enclosed I send you the only book of the kind in my possession here, having just received it as a present from the author.—Benjamin Franklin to Dr. Cadwallader Evans, London, May 5, 1767 (1). PMID:14223741

  17. Molecularly imprinted materials: synthesis, properties, applications

    NASA Astrophysics Data System (ADS)

    Lisichkin, Georgii V.; Krutyakov, Yu A.

    2006-10-01

    This review is devoted to the method of molecular imprinting. The physicochemical fundamentals and mechanisms of covalent and non-covalent molecular imprinting aimed at the development of organic polymeric sorbents capable of molecular recognition are considered. Attention is focused on the preparation of molecular imprints on mineral supports. The mechanisms of molecular recognition in adsorption are discussed. Application fields of materials with molecular imprints are briefly surveyed.

  18. Tet-mediated imprinting erasure in H19 locus following reprogramming of spermatogonial stem cells to induced pluripotent stem cells

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Selective methylation of CpG islands at imprinting control regions (ICR) determines the monoparental expression of a subset of genes. The imprinting marks are protected from global demethylation taking place during pre-implantation development before being reset in primordial germ cells. However, it...

  19. Genomic imprinting and Turner syndrome.

    PubMed

    Bondy, Carolyn A; Hougen, Helen Y; Zhou, Jian; Cheng, Clara M

    2012-05-01

    The term 'genomic imprinting' refers to selective repression of transcription from distinct chromosomal regions determined by their maternal or paternal inheritance. There are two potentially important aspects of imprinting that may manifest in individuals with X monosomy, or Turner syndrome (TS). Given that men are monosomic for Xm while women are mosaic for Xm:Xp, genomic imprinting of important X-linked genes should be associated with sexually dimorphic traits, e.g., social skills, regional fat deposition and adult height. Such X-imprinted traits are predicted to differ in Turner groups monosomic for Xm vs. Xp. We review relevant studies of psychosocial attributes, regional fat distribution and height in TS related to parent of origin for the single normal X chromosome. In addition, we review recent evidence that monosomy for the X chromosome per se, regardless of the parental origin, may disrupt the normal distribution of autosomal imprint patterns. This may contribute to a high rate of fetal loss in human monosomy via impaired placentation in the most severe cases, and to loss of paternal contribution to growth in the mildest manifestation.

  20. Both maternally and paternally imprinted genes regulate seed development in rice.

    PubMed

    Yuan, Jingya; Chen, Sushu; Jiao, Wu; Wang, Longfei; Wang, Limei; Ye, Wenxue; Lu, Jie; Hong, Delin; You, Siliang; Cheng, Zhukuan; Yang, Dong-Lei; Chen, Z Jeffrey

    2017-03-13

    Genetic imprinting refers to the unequal expression of paternal and maternal alleles of a gene in sexually reproducing organisms, including mammals and flowering plants. Although many imprinted genes have been identified in plants, the functions of these imprinted genes have remained largely uninvestigated. We report genome-wide analysis of gene expression, DNA methylation and small RNAs in the rice endosperm and functional tests of five imprinted genes during seed development using Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated gene9 (CRISPR/Cas9) gene editing technology. In the rice endosperm, we identified 162 maternally expressed genes (MEGs) and 95 paternally expressed genes (PEGs), which were associated with miniature inverted-repeat transposable elements, imprinted differentially methylated loci and some 21-22 small interfering RNAs (siRNAs) and long noncoding RNAs (lncRNAs). Remarkably, one-third of MEGs and nearly one-half of PEGs were associated with grain yield quantitative trait loci. Most MEGs and some PEGs were expressed specifically in the endosperm. Disruption of two MEGs increased the amount of small starch granules and reduced grain and embryo size, whereas mutation of three PEGs reduced starch content and seed fertility. Our data indicate that both MEGs and PEGs in rice regulate nutrient metabolism and endosperm development, which optimize seed development and offspring fitness to facilitate parental-offspring coadaptation. These imprinted genes and mechanisms could be used to improve the grain yield of rice and other cereal crops.

  1. Small regulatory RNAs controlled by genomic imprinting and their contribution to human disease.

    PubMed

    Girardot, Michael; Cavaillé, Jérôme; Feil, Robert

    2012-12-01

    More than a hundred protein-coding genes are controlled by genomic imprinting in humans. These atypical genes are organized in chromosomal domains, each of which is controlled by a differentially methylated "imprinting control region" (ICR). How ICRs mediate the parental allele-specific expression of close-by genes is now becoming understood. At several imprinted domains, this epigenetic mechanism involves the action of long non-coding RNAs. It is less well appreciated that imprinted gene domains also transcribe hundreds of microRNA and small nucleolar RNA genes and that these represent the densest clusters of small RNA genes in mammalian genomes. The evolutionary reasons for this remarkable enrichment of small regulatory RNAs at imprinted domains remain unclear. However, recent studies show that imprinted small RNAs modulate specific functions in development and metabolism and also are frequently perturbed in cancer. Here, we review our current understanding of imprinted small RNAs in the human genome and discuss how perturbation of their expression contributes to disease.

  2. Small regulatory RNAs controlled by genomic imprinting and their contribution to human disease

    PubMed Central

    Girardot, Michael; Cavaillé, Jérôme; Feil, Robert

    2012-01-01

    More than a hundred protein-coding genes are controlled by genomic imprinting in humans. These atypical genes are organized in chromosomal domains, each of which is controlled by a differentially methylated "imprinting control region" (ICR). How ICRs mediate the parental allele-specific expression of close-by genes is now becoming understood. At several imprinted domains, this epigenetic mechanism involves the action of long non-coding RNAs. It is less well appreciated that imprinted gene domains also transcribe hundreds of microRNA and small nucleolar RNA genes and that these represent the densest clusters of small RNA genes in mammalian genomes. The evolutionary reasons for this remarkable enrichment of small regulatory RNAs at imprinted domains remain unclear. However, recent studies show that imprinted small RNAs modulate specific functions in development and metabolism and also are frequently perturbed in cancer. Here, we review our current understanding of imprinted small RNAs in the human genome and discuss how perturbation of their expression contributes to disease. PMID:23154539

  3. Molecular imprinting in sol-gel matrix.

    PubMed

    Gupta, Radha; Kumar, Ashok

    2008-01-01

    Molecular imprinting is a newly developed methodology which provides molecular assemblies of desired structures and properties and is being increasingly used for several applications such as in separation processes, microreactors, immunoassays and antibody mimics, catalysis, artificial enzymes, biosensor recognition elements and bio- and chemo-sensors. The ambient processing conditions and versatility of the sol-gel process makes sol-gel glassy matrix suitable for molecular imprinting. The progress of sol-gel based molecular imprinted polymers (MIPs) for various applications can be seen from the growing number of publications. The main focus of the review is molecular imprinting in sol-gel matrix and applications of molecular imprinted sol-gel derived materials for the development of sensors. Combining sol-gel process with molecular imprinting enables to procure the sensors with greater sensitivity and selectivity necessary for sensing applications. The merits, problems, challenges and factors affecting molecular imprinting in sol-gel matrix have been discussed. Considerable attention has been drawn on recent developments like use of organically modified silane precursors (ORMOSILS) for the synthesis of hybrid molecular imprinted polymers (HMIPs) and applying surface sol-gel process for molecular imprinting. The development of molecular imprinted sol-gel nanotubes for biochemical separation and bio-imprinting is a new advancement and is under progress. Templated xerogels and molecularly imprinted sol-gel films provide a good platform for various sensor applications.

  4. Molecularly Imprinted Materials: Towards the Next Generation

    DTIC Science & Technology

    2002-04-05

    SCINTILLATION POLYMERS : A NEW SENSOR CONCEPT Although molecularly imprinted polymers ( MIPs ) often display high binding affinity and specificity mimicking... sensors have been demonstrated over the past years. In general, molecular imprinting can be defined as a process of target directed synthesis of...efficiency. For these reasons imprinted polymer beads are preferable. Although the well-established suspension and dispersion polymerization methods

  5. High Gestational Folic Acid Supplementation Alters Expression of Imprinted and Candidate Autism Susceptibility Genes in a sex-Specific Manner in Mouse Offspring.

    PubMed

    Barua, Subit; Kuizon, Salomon; Brown, W Ted; Junaid, Mohammed A

    2016-02-01

    Maternal nutrients play critical roles in modulating epigenetic events and exert long-term influences on the progeny's health. Folic acid (FA) supplementation during pregnancy has decreased the incidence of neural tube defects in newborns, but the influence of high doses of maternal FA supplementation on infants' brain development is unclear. The present study was aimed at investigating the effects of a high dose of gestational FA on the expression of genes in the cerebral hemispheres (CHs) of 1-day-old pups. One week prior to mating and throughout the entire period of gestation, female C57BL/6J mice were fed a diet, containing FA at either 2 mg/kg (control diet (CD)) or 20 mg/kg (high maternal folic acid (HMFA)). At postnatal day 1, pups from different dams were sacrificed and CH tissues were collected. Quantitative RT-PCR and Western blot analysis confirmed sex-specific alterations in the expression of several genes that modulate various cellular functions (P < 0.05) in pups from the HMFA group. Genomic DNA methylation analysis showed no difference in the level of overall methylation in pups from the HMFA group. These findings demonstrate that HMFA supplementation alters offsprings' CH gene expression in a sex-specific manner. These changes may influence infants' brain development.

  6. New Perspectives on Genomic Imprinting, an Essential and Multifaceted Mode of Epigenetic Control in the Developing and Adult Brain

    PubMed Central

    Perez, Julio D.; Rubinstein, Nimrod D.; Dulac, Catherine

    2016-01-01

    Mammalian evolution entailed multiple innovations in gene regulation, including the emergence of genomic imprinting, an epigenetic regulation leading to the preferential expression of a gene from its maternal or paternal allele. Genomic imprinting is highly prevalent in the brain, yet, until recently, its central roles in neural processes have not been fully appreciated. Here, we provide a comprehensive survey of adult and developmental brain functions influenced by imprinted genes, from neural development and wiring to synaptic function and plasticity, energy balance, social behaviors, emotions, and cognition. We further review the widespread identification of parental biases alongside monoallelic expression in brain tissues, discuss their potential roles in dosage regulation of key neural pathways, and suggest possible mechanisms underlying the dynamic regulation of imprinting in the brain. This review should help provide a better understanding of the significance of genomic imprinting in the normal and pathological brain of mammals including humans. PMID:27145912

  7. Clinical features associated with copy number variations of the 14q32 imprinted gene cluster.

    PubMed

    Rosenfeld, Jill A; Fox, Joyce E; Descartes, Maria; Brewer, Fallon; Stroud, Tracy; Gorski, Jerome L; Upton, Sheila J; Moeschler, John B; Monteleone, Berrin; Neill, Nicholas J; Lamb, Allen N; Ballif, Blake C; Shaffer, Lisa G; Ravnan, J Britt

    2015-02-01

    Uniparental disomy (UPD) for imprinted chromosomes can cause abnormal phenotypes due to absent or overexpression of imprinted genes. UPD(14)pat causes a unique constellation of features including thoracic skeletal anomalies, polyhydramnios, placentomegaly, and limited survival; its hypothesized cause is overexpression of paternally expressed RTL1, due to absent regulatory effects of maternally expressed RTL1as. UPD(14)mat causes a milder condition with hypotonia, growth failure, and precocious puberty; its hypothesized cause is absence of paternally expressed DLK1. To more clearly establish how gains and losses of imprinted genes can cause disease, we report six individuals with copy number variations of the imprinted 14q32 region identified through clinical microarray-based comparative genomic hybridization. Three individuals presented with UPD(14)mat-like phenotypes (Temple syndrome) and had apparently de novo deletions spanning the imprinted region, including DLK1. One of these deletions was shown to be on the paternal chromosome. Two individuals with UPD(14)pat-like phenotypes had 122-154kb deletions on their maternal chromosomes that included RTL1as but not the differentially methylated regions that regulate imprinted gene expression, providing further support for RTL1 overexpression as a cause for the UPD(14)pat phenotype. The sixth individual is tetrasomic for a 1.7Mb segment, including the imprinted region, and presents with intellectual disability and seizures but lacks significant phenotypic overlap with either UPD(14) syndrome. Therefore, the 14q32 imprinted region is dosage sensitive, with deletions of different critical regions causing UPD(14)mat- and UPD(14)pat-like phenotypes, while copy gains are likely insufficient to recapitulate these phenotypes.

  8. Dissecting genomic imprinting and genetic conflict from a game theory prospective. Comment on: ;Epigenetic game theory: How to compute the epigenetic control of maternal-to-zygotic transition; by Qian Wang et al.

    NASA Astrophysics Data System (ADS)

    Cui, Yuehua; Yang, Haitao

    2017-03-01

    Epigenetics typically refers to changes in the structure of a chromosome that affect gene activity and expression. Genomic imprinting is a special type of epigenetic phenomenon in which the expression of an allele depends on its parental origin. When an allele inherited from the mother (or father) is imprinted (i.e., silent), it is termed as maternal (or paternal) imprinting. Imprinting is often resulted from DNA methylation and tends to cluster together in the genome [1]. It has been shown to play a key role in many genetic disorders in humans [2]. Imprinting is heritable and undergoes a reprogramming process in gametes before and after fertilization [1]. Sometimes the reprogramming process is not reversible, leading to the loss of imprinting [3]. Although efforts have been made to experimentally or computationally infer imprinting genes, the underlying molecular mechanism that leads to unbalanced allelic expression is still largely unknown.

  9. Targeting and Imaging of Cancer Cells via Monosaccharide-Imprinted Fluorescent Nanoparticles

    PubMed Central

    Wang, Shuangshou; Yin, Danyang; Wang, Wenjing; Shen, Xiaojing; Zhu, Jun-Jie; Chen, Hong-Yuan; Liu, Zhen

    2016-01-01

    The recognition of cancer cells is a key for cancer diagnosis and therapy, but the specificity highly relies on the use of biorecognition molecules particularly antibodies. Because biorecognition molecules suffer from some apparent disadvantages, such as hard to prepare and poor storage stability, novel alternatives that can overcome these disadvantages are highly important. Here we present monosaccharide-imprinted fluorescent nanoparticles (NPs) for targeting and imaging of cancer cells. The molecularly imprinted polymer (MIP) probe was fluorescein isothiocyanate (FITC) doped silica NPs with a shell imprinted with sialic acid, fucose or mannose as the template. The monosaccharide-imprinted NPs exhibited high specificity toward the target monosaccharides. As the template monosaccharides used are over-expressed on cancer cells, these monosaccharide-imprinted NPs allowed for specific targeting cancer cells over normal cells. Fluorescence imaging of human hepatoma carcinoma cells (HepG-2) over normal hepatic cells (L-02) and mammary cancer cells (MCF-7) over normal mammary epithelial cells (MCF-10A) by these NPs was demonstrated. As the imprinting approach employed herein is generally applicable and highly efficient, monosaccharide-imprinted NPs can be promising probes for targeting cancer cells. PMID:26948803

  10. Targeting and Imaging of Cancer Cells via Monosaccharide-Imprinted Fluorescent Nanoparticles

    NASA Astrophysics Data System (ADS)

    Wang, Shuangshou; Yin, Danyang; Wang, Wenjing; Shen, Xiaojing; Zhu, Jun-Jie; Chen, Hong-Yuan; Liu, Zhen

    2016-03-01

    The recognition of cancer cells is a key for cancer diagnosis and therapy, but the specificity highly relies on the use of biorecognition molecules particularly antibodies. Because biorecognition molecules suffer from some apparent disadvantages, such as hard to prepare and poor storage stability, novel alternatives that can overcome these disadvantages are highly important. Here we present monosaccharide-imprinted fluorescent nanoparticles (NPs) for targeting and imaging of cancer cells. The molecularly imprinted polymer (MIP) probe was fluorescein isothiocyanate (FITC) doped silica NPs with a shell imprinted with sialic acid, fucose or mannose as the template. The monosaccharide-imprinted NPs exhibited high specificity toward the target monosaccharides. As the template monosaccharides used are over-expressed on cancer cells, these monosaccharide-imprinted NPs allowed for specific targeting cancer cells over normal cells. Fluorescence imaging of human hepatoma carcinoma cells (HepG-2) over normal hepatic cells (L-02) and mammary cancer cells (MCF-7) over normal mammary epithelial cells (MCF-10A) by these NPs was demonstrated. As the imprinting approach employed herein is generally applicable and highly efficient, monosaccharide-imprinted NPs can be promising probes for targeting cancer cells.

  11. Development of a Biosensor for Detection of Pleural Mesothelioma Cancer Biomarker Using Surface Imprinting

    PubMed Central

    Mathur, Aabhas; Blais, Steven; Goparaju, Chandra M. V.; Neubert, Thomas; Pass, Harvey; Levon, Kalle

    2013-01-01

    Hyaluronan-linked protein 1 (HAPLN1) which has been shown to be highly expressed in malignant pleural mesotheliomas (MPM), was detected in serum using an electrochemical surface-imprinting method. First, the detection method was optimized using Bovine serum albumin (BSA) as a model protein to mimic the optimal conditions required to imprint the similar molecular weight protein HAPLN1. BSA was imprinted on the gold electrode with hydroxyl terminated alkane thiols, which formed a self-assembled monolayer (SAM) around BSA. The analyte (BSA) was then washed away and its imprint (empty cavity with shape-memory) was used for detection of BSA in a solution, using electrochemical open-circuit potential method, namely potentiometry. Factors considered to optimize the conditions include incubation time, protein concentration, limit of detection and size of electrode. Matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) was used to confirm selectivity of imprints. With the obtained imprinting control parameters, HAPLN1 was imprinted in duplicate and the detection of spiked HAPLN1 was successfully conducted in serum. PMID:23516416

  12. Imprinted Polymers in Wastewater Treatment

    SciTech Connect

    Eastman, Christopher; Goodrich, Scott; Gartner, Isabelle; Mueller, Anja

    2004-03-31

    In wastewater treatment, a method that specifically recognizes a variety of impurities in a flexible manner would be useful for treatment facilities with varying needs. Current purification techniques (i.e. bacteria, oxidation, reduction, precipitation and filtration) are nonspecific and difficult to control in complex mixtures. Heavy metal removal is particularly important in improving the efficiency of wastewater treatment, as they inhibit or even destroy the bacteria used for filtration. Imprinting polymerization is a technique that allows for the efficient removal of specific compounds and has been used in purification of enantiomers. It has potential to be applied in wastewater systems with the impurities acting as the template for the imprinting polymerization. The polymer with the bound impurities intact can then be removed via precipitation. After removal of the impurity the polymer can be reused. Data for the imprinting polymerization of polyacrylates and polyacrylamides for several metal complexes will be presented. Imprinting polymerization in combination with emulsion polymerization to improve the removal of hydrophobic contaminants will be described. Removal efficiencies will be presented and compared with conventional wastewater treatment methods.

  13. Molecularly imprinted polymer sensor arrays.

    PubMed

    Shimizu, Ken D; Stephenson, Clifton J

    2010-12-01

    The sensor array format has proved an effective method of transforming sensors of modest selectivity into highly selective and discriminating sensors. The primary challenge in developing new sensor arrays is collecting together a sufficient number of recognition elements that possess different binding affinities for the analytes of interest. In this regard, the use of molecularly imprinted polymers (MIPs) as the recognition elements in sensor arrays has a number of unique advantages. MIPs can be rapidly and inexpensively prepared with different selectivities and tuned with different selectivity patterns via the choice of templates in the imprinting process. The array format also helps compensate for the low selectivities and high cross-reactivities of MIP sensors. These attractive qualities of MIP sensor arrays have been demonstrated in recent examples, which have established the viability and generality of the approach. In particular, the versatility of the imprinting process enables MIP sensor arrays to be tailored to specific analytes. MIP sensor arrays have also shown surprisingly broad utility, as even analytes that were not used as templates in the imprinting process can be effectively discriminated.

  14. DNA methylation and gene expression changes derived from assisted reproductive technologies can be decreased by reproductive fluids

    PubMed Central

    Canovas, Sebastian; Ivanova, Elena; Romar, Raquel; García-Martínez, Soledad; Soriano-Úbeda, Cristina; García-Vázquez, Francisco A; Saadeh, Heba; Andrews, Simon; Kelsey, Gavin; Coy, Pilar

    2017-01-01

    The number of children born since the origin of Assisted Reproductive Technologies (ART) exceeds 5 million. The majority seem healthy, but a higher frequency of defects has been reported among ART-conceived infants, suggesting an epigenetic cost. We report the first whole-genome DNA methylation datasets from single pig blastocysts showing differences between in vivo and in vitro produced embryos. Blastocysts were produced in vitro either without (C-IVF) or in the presence of natural reproductive fluids (Natur-IVF). Natur-IVF embryos were of higher quality than C-IVF in terms of cell number and hatching ability. RNA-Seq and DNA methylation analyses showed that Natur-IVF embryos have expression and methylation patterns closer to in vivo blastocysts. Genes involved in reprogramming, imprinting and development were affected by culture, with fewer aberrations in Natur-IVF embryos. Methylation analysis detected methylated changes in C-IVF, but not in Natur-IVF, at genes whose methylation could be critical, such as IGF2R and NNAT. DOI: http://dx.doi.org/10.7554/eLife.23670.001 PMID:28134613

  15. DNA methylation and gene expression changes derived from assisted reproductive technologies can be decreased by reproductive fluids.

    PubMed

    Canovas, Sebastian; Ivanova, Elena; Romar, Raquel; García-Martínez, Soledad; Soriano-Úbeda, Cristina; García-Vázquez, Francisco A; Saadeh, Heba; Andrews, Simon; Kelsey, Gavin; Coy, Pilar

    2017-02-01

    The number of children born since the origin of Assisted Reproductive Technologies (ART) exceeds 5 million. The majority seem healthy, but a higher frequency of defects has been reported among ART-conceived infants, suggesting an epigenetic cost. We report the first whole-genome DNA methylation datasets from single pig blastocysts showing differences between in vivo and in vitro produced embryos. Blastocysts were produced in vitro either without (C-IVF) or in the presence of natural reproductive fluids (Natur-IVF). Natur-IVF embryos were of higher quality than C-IVF in terms of cell number and hatching ability. RNA-Seq and DNA methylation analyses showed that Natur-IVF embryos have expression and methylation patterns closer to in vivo blastocysts. Genes involved in reprogramming, imprinting and development were affected by culture, with fewer aberrations in Natur-IVF embryos. Methylation analysis detected methylated changes in C-IVF, but not in Natur-IVF, at genes whose methylation could be critical, such as IGF2R and NNAT.

  16. Human Oocyte-Derived Methylation Differences Persist in the Placenta Revealing Widespread Transient Imprinting

    PubMed Central

    Court, Franck; Martin-Trujillo, Alex; Tayama, Chiharu; Kondova, Ivanela; Bontrop, Ronald; Poo-Llanillo, Maria Eugenia; Nakabayashi, Kazuhiko; Simón, Carlos; Monk, David

    2016-01-01

    Thousands of regions in gametes have opposing methylation profiles that are largely resolved during the post-fertilization epigenetic reprogramming. However some specific sequences associated with imprinted loci survive this demethylation process. Here we present the data describing the fate of germline-derived methylation in humans. With the exception of a few known paternally methylated germline differentially methylated regions (DMRs) associated with known imprinted domains, we demonstrate that sperm-derived methylation is reprogrammed by the blastocyst stage of development. In contrast a large number of oocyte-derived methylation differences survive to the blastocyst stage and uniquely persist as transiently methylated DMRs only in the placenta. Furthermore, we demonstrate that this phenomenon is exclusive to primates, since no placenta-specific maternal methylation was observed in mouse. Utilizing single cell RNA-seq datasets from human preimplantation embryos we show that following embryonic genome activation the maternally methylated transient DMRs can orchestrate imprinted expression. However despite showing widespread imprinted expression of genes in placenta, allele-specific transcriptional profiling revealed that not all placenta-specific DMRs coordinate imprinted expression and that this maternal methylation may be absent in a minority of samples, suggestive of polymorphic imprinted methylation. PMID:27835649

  17. Paternally expressed genes predominate in the placenta.

    PubMed

    Wang, Xu; Miller, Donald C; Harman, Rebecca; Antczak, Douglas F; Clark, Andrew G

    2013-06-25

    The discovery of genomic imprinting through studies of manipulated mouse embryos indicated that the paternal genome has a major influence on placental development. However, previous research has not demonstrated paternal bias in imprinted genes. We applied RNA sequencing to trophoblast tissue from reciprocal hybrids of horse and donkey, where genotypic differences allowed parent-of-origin identification of most expressed genes. Using this approach, we identified a core group of 15 ancient imprinted genes, of which 10 were paternally expressed. An additional 78 candidate imprinted genes identified by RNA sequencing also showed paternal bias. Pyrosequencing was used to confirm the imprinting status of six of the genes, including the insulin receptor (INSR), which may play a role in growth regulation with its reciprocally imprinted ligand, histone acetyltransferase-1 (HAT1), a gene involved in chromatin modification, and lymphocyte antigen 6 complex, locus G6C, a newly identified imprinted gene in the major histocompatibility complex. The 78 candidate imprinted genes displayed parent-of-origin expression bias in placenta but not fetus, and most showed less than 100% silencing of the imprinted allele. Some displayed variability in imprinting status among individuals. This variability results in a unique epigenetic signature for each placenta that contributes to variation in the intrauterine environment and thus presents the opportunity for natural selection to operate on parent-of-origin differential regulation. Taken together, these features highlight the plasticity of imprinting in mammals and the central importance of the placenta as a target tissue for genomic imprinting.

  18. Prenatal low protein and postnatal high fat diets induce rapid adipose tissue growth by inducing Igf2 expression in Sprague Dawley rat offspring

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maternal low protein diets during prenatal development contribute to the development of obesity and insulin resistance in offspring. In this study, obese-prone Sprague -Dawley rats were fed diets having either 8% (low protein, LP) or 20% (normal protein, NP) protein for 3-wk prior to conception and...

  19. A mono-allelic bivalent chromatin domain controls tissue-specific imprinting at Grb10.

    PubMed

    Sanz, Lionel A; Chamberlain, Stormy; Sabourin, Jean-Charles; Henckel, Amandine; Magnuson, Terry; Hugnot, Jean-Philippe; Feil, Robert; Arnaud, Philippe

    2008-10-08

    Genomic imprinting is a developmental mechanism that mediates parent-of-origin-specific expression in a subset of genes. How the tissue specificity of imprinted gene expression is controlled remains poorly understood. As a model to address this question, we studied Grb10, a gene that displays brain-specific expression from the paternal chromosome. Here, we show in the mouse that the paternal promoter region is marked by allelic bivalent chromatin enriched in both H3K4me2 and H3K27me3, from early embryonic stages onwards. This is maintained in all somatic tissues, but brain. The bivalent domain is resolved upon neural commitment, during the developmental window in which paternal expression is activated. Our data indicate that bivalent chromatin, in combination with neuronal factors, controls the paternal expression of Grb10 in brain. This finding highlights a novel mechanism to control tissue-specific imprinting.

  20. Genome-wide histone state profiling of fibroblasts from the opossum, Monodelphis domestica, identifies the first marsupial-specific imprinted gene

    PubMed Central

    2014-01-01

    Background Imprinted genes have been extensively documented in eutherian mammals and found to exhibit significant interspecific variation in the suites of genes that are imprinted and in their regulation between tissues and developmental stages. Much less is known about imprinted loci in metatherian (marsupial) mammals, wherein studies have been limited to a small number of genes previously known to be imprinted in eutherians. We describe the first ab initio search for imprinted marsupial genes, in fibroblasts from the opossum, Monodelphis domestica, based on a genome-wide ChIP-seq strategy to identify promoters that are simultaneously marked by mutually exclusive, transcriptionally opposing histone modifications. Results We identified a novel imprinted gene (Meis1) and two additional monoallelically expressed genes, one of which (Cstb) showed allele-specific, but non-imprinted expression. Imprinted vs. allele-specific expression could not be resolved for the third monoallelically expressed gene (Rpl17). Transcriptionally opposing histone modifications H3K4me3, H3K9Ac, and H3K9me3 were found at the promoters of all three genes, but differential DNA methylation was not detected at CpG islands at any of these promoters. Conclusions In generating the first genome-wide histone modification profiles for a marsupial, we identified the first gene that is imprinted in a marsupial but not in eutherian mammals. This outcome demonstrates the practicality of an ab initio discovery strategy and implicates histone modification, but not differential DNA methylation, as a conserved mechanism for marking imprinted genes in all therian mammals. Our findings suggest that marsupials use multiple epigenetic mechanisms for imprinting and support the concept that lineage-specific selective forces can produce sets of imprinted genes that differ between metatherian and eutherian lines. PMID:24484454

  1. Stability of genomic imprinting in embryonic stem cells: lessons from assisted reproductive technology.

    PubMed

    Huntriss, John; Picton, Helen M

    2008-05-01

    Imprinted genes are expressed predominantly or exclusively from one allele only. This mode of gene expression makes the regulation of imprinted genes susceptible to epigenetic insults, which may in turn lead to disease. There is compelling experimental evidence that certain aspects of assisted reproductive technology (ART) such as in vitro cell culture may have adverse effects on the regulation of epigenetic information in mammalian embryos, including the disruption of imprinted genes and epigenetic regulators. Moreover, in humans, disorders of genomic imprinting have been reported in children conceived by ART. The derivation and in vitro culture of embryonic stem (ES) cells are potential points of origin for epigenetic abnormalities. There is evidence that defects of genomic imprinting occur in mouse embryonic stem cells, with similar data now emerging in related studies in non-human primate and human ES cells. It is therefore pertinent to rigorously assess the epigenetic status of all stem cells and their derivatives prior to their therapeutic use in humans. Focusing on the stability of genomic imprinting, this review discusses the current evidence for epigenetic disruption in mammalian embryonic stem cells in light of the epigenetic disruption observed in ART-derived mammalian embryos.

  2. Epigenetic deregulation of genomic imprinting in human disorders and following assisted reproduction.

    PubMed

    Arnaud, Philippe; Feil, Robert

    2005-06-01

    Imprinted genes play important roles in the regulation of growth and development, and several have been shown to influence behavior. Their allele-specific expression depends on inheritance from either the mother or the father, and is regulated by "imprinting control regions" (ICRs). ICRs are controlled by DNA methylation, which is present on one of the two parental alleles only. These allelic methylation marks are established in either the female or the male germline, following the erasure of preexisting DNA methylation in the primordial germ cells. After fertilization, the allelic DNA methylation at ICRs is maintained in all somatic cells of the developing embryo. This epigenetic "life cycle" of imprinting (germline erasure, germline establishment, and somatic maintenance) can be disrupted in several human diseases, including Beckwith-Wiedemann syndrome (BWS), Prader-Willi syndrome (PWS), Angelman syndrome and Hydatidiform mole. In the neurodevelopmental Rett syndrome, the way the ICR mediates imprinted expression is perturbed. Recent studies indicate that assisted reproduction technologies (ART) can sometimes affect the epigenetic cycle of imprinting as well, and that this gives rise to imprinting disease syndromes. This finding warrants careful monitoring of the epigenetic effects, and absolute risks, of currently used and novel reproduction technologies.

  3. Characterization of global loss of imprinting in fetal overgrowth syndrome induced by assisted reproduction.

    PubMed

    Chen, Zhiyuan; Hagen, Darren E; Elsik, Christine G; Ji, Tieming; Morris, Collin James; Moon, Laura Emily; Rivera, Rocío Melissa

    2015-04-14

    Embryos generated with the use of assisted reproductive technologies (ART) can develop overgrowth syndromes. In ruminants, the condition is referred to as large offspring syndrome (LOS) and exhibits variable phenotypic abnormalities including overgrowth, enlarged tongue, and abdominal wall defects. These characteristics recapitulate those observed in the human loss-of-imprinting (LOI) overgrowth syndrome Beckwith-Wiedemann (BWS). We have recently shown LOI at the KCNQ1 locus in LOS, the most common epimutation in BWS. Although the first case of ART-induced LOS was reported in 1995, studies have not yet determined the extent of LOI in this condition. Here, we determined allele-specific expression of imprinted genes previously identified in human and/or mouse in day ∼105 Bos taurus indicus × Bos taurus taurus F1 hybrid control and LOS fetuses using RNAseq. Our analysis allowed us to determine the monoallelic expression of 20 genes in tissues of control fetuses. LOS fetuses displayed variable LOI compared with controls. Biallelic expression of imprinted genes in LOS was associated with tissue-specific hypomethylation of the normally methylated parental allele. In addition, a positive correlation was observed between body weight and the number of biallelically expressed imprinted genes in LOS fetuses. Furthermore, not only was there loss of allele-specific expression of imprinted genes in LOS, but also differential transcript amounts of these genes between control and overgrown fetuses. In summary, we characterized previously unidentified imprinted genes in bovines and identified misregulation of imprinting at multiple loci in LOS. We concluded that LOS is a multilocus LOI syndrome, as is BWS.

  4. Genomic imprinting in plants: what makes the functions of paternal and maternal genes different in endosperm formation?

    PubMed

    Ohnishi, Takayuki; Sekine, Daisuke; Kinoshita, Tetsu

    2014-01-01

    Genomic imprinting refers to the unequal expression of maternal and paternal alleles according to the parent of origin. This phenomenon is regulated by epigenetic controls and has been reported in placental mammals and flowering plants. Although conserved characteristics can be identified across a wide variety of taxa, it is believed that genomic imprinting evolved independently in animal and plant lineages. Plant genomic imprinting occurs most obviously in the endosperm, a terminally differentiated embryo-nourishing tissue that is required for seed development. Recent studies have demonstrated a close relationship between genomic imprinting and the development of elaborate defense mechanisms against parasitic elements during plant sexual reproduction. In this chapter, we provide an introductory description of genomic imprinting in plants, and focus on recent advances in our understanding of its role in endosperm development, the frontline of maternal and paternal epigenomes.

  5. Identification of imprinted genes using a novel screening method based on asynchronous DNA replication

    SciTech Connect

    Kawame, H.; Hansen, R.S.; Gartler, S.M.

    1994-09-01

    Genomic imprinting refers to the process of epigenetic change that occurs during germ cell development that results in either maternal- or paternal-specific gene expression. Identification of imprinted genes is of primary importance to the understanding of imprinting mechanisms and the role of specific imprinted genes in human disease. Recently, it has been established that chromosomal regions known to contain imprinted genes replicate asynchronously. We propose a novel screening method to identify imprinted genes based on replication asynchrony as a marker for imprinted domains. Dividing human cells were pulse-labeled with BrdU and separated into different fractions of S-phase by flow cytometry. A library of late-replicating inter-Alu sequences should be enriched in gene-associated sequences that replicate early on one chromosome and late on the other homologue. Clones were analyzed for replication timing by hybridization to inter-Alu replication profiles. Candidates for replication asynchrony exhibited broad or biphasic replication timing, and these were analyzed for chromosomal location by hybridizations to inter-Alu products from a hybrid mapping panel. Initial screening of 123 clones resulted in 3 asynchronously-replicating clones that localized to single chromosomes. Chromosome 17 and chromosome 19 candidates might be located in regions thought to be imprinted by synteny with mouse chromosomes. A chromosome 15 clone was further characterized because of its possible localization to the Prader-Willi/Angelman locus. This sequence was localized outside the region deleted in Prader-Willi patients, and was found to be expressed in human cell lines. Replication asynchrony for this sequence appears to be polymorphic because cells derived from some individuals indicated synchronous replication. This appears to be the first example of a polymorphism in replication asynchrony.

  6. Imprint Reduction with Shaped Pulses

    NASA Astrophysics Data System (ADS)

    Collins, T. J. B.; Skupsky, S.

    2000-10-01

    A novel technique for reducing laser imprint in OMEGA cryogenic targets has been developed. Standard ICF cryogenic targets consist of a shell of DT ice with a thin outer layer of CH. The presence of the CH layer gives rise to a brief period of early-time growth by the Rayleigh-Taylor (RT) instability, which effectively increases the amount of laser imprint by about a factor of 2. Two-dimensional ORCHID simulations show that by introducing a short, high-intensity spike at the start of the implosion, this early-time growth can be significantly reduced with only a small change to the calculated 1-D neutron yield. This work was supported by the U.S. Department of Energy Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC03-92SF19460.

  7. "imprinting" in General Relativity Tests?

    NASA Astrophysics Data System (ADS)

    Iorio, Lorenzo

    We investigate possible a priori "imprinting" of general relativity itself on spaceraft-based tests of it. We deal with some performed or proposed time-delay ranging experiments in the Sun's gravitational field. The "imprint" of general relativity on the Astronomical Unit and the solar gravitational constant GM⊙, not solved for in the spacecraft-based time-delay test performed so far, may induce an a priori bias of the order of 10-6 in typical solar system ranging experiments aimed to measuring the space curvature PPN parameter γ. It is too small by one order of magnitude to be of concern for the performed Cassini experiment, but it would affect future planned or proposed tests aiming to reach a 10-7-10-9 accuracy in determining γ.

  8. Maternal stress, preterm birth, and DNA methylation at imprint regulatory sequences in humans.

    PubMed

    Vidal, Adriana C; Benjamin Neelon, Sara E; Liu, Ying; Tuli, Abbas M; Fuemmeler, Bernard F; Hoyo, Cathrine; Murtha, Amy P; Huang, Zhiqing; Schildkraut, Joellen; Overcash, Francine; Kurtzberg, Joanne; Jirtle, Randy L; Iversen, Edwin S; Murphy, Susan K

    2014-01-01

    In infants exposed to maternal stress in utero, phenotypic plasticity through epigenetic events may mechanistically explain increased risk of preterm birth (PTB), which confers increased risk for neurodevelopmental disorders, cardiovascular disease, and cancers in adulthood. We examined associations between prenatal maternal stress and PTB, evaluating the role of DNA methylation at imprint regulatory regions. We enrolled women from prenatal clinics in Durham, NC. Stress was measured in 537 women at 12 weeks of gestation using the Perceived Stress Scale. DNA methylation at differentially methylated regions (DMRs) associated with H19, IGF2, MEG3, MEST, SGCE/PEG10, PEG3, NNAT, and PLAGL1 was measured from peripheral and cord blood using bisulfite pyrosequencing in a sub-sample of 79 mother-infant pairs. We examined associations between PTB and stress and evaluated differences in DNA methylation at each DMR by stress. Maternal stress was not associated with PTB (OR = 0.98; 95% CI, 0.40-2.40; P = 0.96), after adjustment for maternal body mass index (BMI), income, and raised blood pressure. However, elevated stress was associated with higher infant DNA methylation at the MEST DMR (2.8% difference, P < 0.01) after adjusting for PTB. Maternal stress may be associated with epigenetic changes at MEST, a gene relevant to maternal care and obesity. Reduced prenatal stress may support the epigenomic profile of a healthy infant.

  9. Genome-wide screen of genes imprinted in sorghum endosperm, and the roles of allelic differential cytosine methylation.

    PubMed

    Zhang, Meishan; Li, Ning; He, Wenan; Zhang, Huakun; Yang, Wei; Liu, Bao

    2016-02-01

    Imprinting is an epigenetic phenomenon referring to allele-biased expression of certain genes depending on their parent of origin. Accumulated evidence suggests that, while imprinting is a conserved mechanism across kingdoms, the identities of the imprinted genes are largely species-specific. Using deep RNA sequencing of endosperm 14 days after pollination in sorghum, 5683 genes (29.27% of the total 19 418 expressed genes) were found to harbor diagnostic single nucleotide polymorphisms between two parental lines. The analysis of parent-of-origin expression patterns in the endosperm of a pair of reciprocal F1 hybrids between the two sorghum lines led to identification of 101 genes with ≥ fivefold allelic expression difference in both hybrids, including 85 maternal expressed genes (MEGs) and 16 paternal expressed genes (PEGs). Thirty of these genes were previously identified as imprinted in endosperm of maize (Zea mays), rice (Oryza sativa) or Arabidopsis, while the remaining 71 genes are sorghum-specific imprinted genes relative to these three plant species. Allele-biased expression of virtually all of the 14 tested imprinted genes (nine MEGs and five PEGs) was validated by pyrosequencing using independent sources of RNA from various developmental stages and dissected parts of endosperm. Forty-six imprinted genes (30 MEGs and 16 PEGs) were assayed by quantitative RT-PCR, and the majority of them showed endosperm-specific or preferential expression relative to embryo and other tissues. DNA methylation analysis of the 5' upstream region and gene body for seven imprinted genes indicated that, while three of the four PEGs were associated with hypomethylation of maternal alleles, no MEG was associated with allele-differential methylation.

  10. A reporter model to visualize imprinting stability at the Dlk1 locus during mouse development and in pluripotent cells

    PubMed Central

    Swanzey, Emily

    2016-01-01

    Genomic imprinting results in the monoallelic expression of genes that encode important regulators of growth and proliferation. Dysregulation of imprinted genes, such as those within the Dlk1-Dio3 locus, is associated with developmental syndromes and specific diseases. Our ability to interrogate causes of imprinting instability has been hindered by the absence of suitable model systems. Here, we describe a Dlk1 knock-in reporter mouse that enables single-cell visualization of allele-specific expression and prospective isolation of cells, simultaneously. We show that this ‘imprinting reporter mouse’ can be used to detect tissue-specific Dlk1 expression patterns in developing embryos. We also apply this system to pluripotent cell culture and demonstrate that it faithfully indicates DNA methylation changes induced upon cellular reprogramming. Finally, the reporter system reveals the role of elevated oxygen levels in eroding imprinted Dlk1 expression during prolonged culture and in vitro differentiation. The possibility to study allele-specific expression in different contexts makes our reporter system a useful tool to dissect the regulation of genomic imprinting in normal development and disease. PMID:27729406

  11. The Haglund imprint on the patella.

    PubMed

    Graf, J; Bernd, L; Simank, H G; Niethard, F U

    1993-12-01

    Seven hundred and five radiographs of the knee were examined and 17.6% showed a so-called Haglund imprint on the patella. The incidence was the same in patients with chondromalacia and in a control group. There was no statistical difference regarding age, sex and body weight. Haglund's imprint is a variation from the normal and is of no diagnostic value.

  12. Tools for fluorescent molecularly imprinted polymers.

    PubMed

    Rathbone, Daniel L; Bains, Ajeet

    2005-01-15

    A linear co-polymer of hexyl acrylate and quinine acrylate was prepared anchored to cellulose filtration membranes. These were used to probe quenching of the tethered fluorophore by test compounds in solution for the validation of imprinted polymer fluorescence studies. The results are compared with simple solution phase quenching studies and also for two membrane-bound imprinted polymers containing the same fluorophore.

  13. Distributed feedback imprinted electrospun fiber lasers.

    PubMed

    Persano, Luana; Camposeo, Andrea; Del Carro, Pompilio; Fasano, Vito; Moffa, Maria; Manco, Rita; D'Agostino, Stefania; Pisignano, Dario

    2014-10-01

    Imprinted, distributed feedback lasers are demonstrated on individual, active electrospun polymer nanofibers. In addition to advantages related to miniaturization, optical confinement and grating nanopatterning lead to a significant threshold reduction compared to conventional thin-film lasers. The possibility of imprinting arbitrary photonic crystal geometries on electrospun lasing nanofibers opens new opportunities for realizing optical circuits and chips.

  14. Loss of Gnas imprinting differentially affects REM/NREM sleep and cognition in mice.

    PubMed

    Lassi, Glenda; Ball, Simon T; Maggi, Silvia; Colonna, Giovanni; Nieus, Thierry; Cero, Cheryl; Bartolomucci, Alessandro; Peters, Jo; Tucci, Valter

    2012-01-01

    It has been suggested that imprinted genes are important in the regulation of sleep. However, the fundamental question of whether genomic imprinting has a role in sleep has remained elusive up to now. In this work we show that REM and NREM sleep states are differentially modulated by the maternally expressed imprinted gene Gnas. In particular, in mice with loss of imprinting of Gnas, NREM and complex cognitive processes are enhanced while REM and REM-linked behaviors are inhibited. This is the first demonstration that a specific overexpression of an imprinted gene affects sleep states and related complex behavioral traits. Furthermore, in parallel to the Gnas overexpression, we have observed an overexpression of Ucp1 in interscapular brown adipose tissue (BAT) and a significant increase in thermoregulation that may account for the REM/NREM sleep phenotypes. We conclude that there must be significant evolutionary advantages in the monoallelic expression of Gnas for REM sleep and for the consolidation of REM-dependent memories. Conversely, biallelic expression of Gnas reinforces slow wave activity in NREM sleep, and this results in a reduction of uncertainty in temporal decision-making processes.

  15. Loss of Gnas Imprinting Differentially Affects REM/NREM Sleep and Cognition in Mice

    PubMed Central

    Lassi, Glenda; Ball, Simon T.; Maggi, Silvia; Colonna, Giovanni; Nieus, Thierry; Cero, Cheryl; Bartolomucci, Alessandro; Peters, Jo; Tucci, Valter

    2012-01-01

    It has been suggested that imprinted genes are important in the regulation of sleep. However, the fundamental question of whether genomic imprinting has a role in sleep has remained elusive up to now. In this work we show that REM and NREM sleep states are differentially modulated by the maternally expressed imprinted gene Gnas. In particular, in mice with loss of imprinting of Gnas, NREM and complex cognitive processes are enhanced while REM and REM–linked behaviors are inhibited. This is the first demonstration that a specific overexpression of an imprinted gene affects sleep states and related complex behavioral traits. Furthermore, in parallel to the Gnas overexpression, we have observed an overexpression of Ucp1 in interscapular brown adipose tissue (BAT) and a significant increase in thermoregulation that may account for the REM/NREM sleep phenotypes. We conclude that there must be significant evolutionary advantages in the monoallelic expression of Gnas for REM sleep and for the consolidation of REM–dependent memories. Conversely, biallelic expression of Gnas reinforces slow wave activity in NREM sleep, and this results in a reduction of uncertainty in temporal decision-making processes. PMID:22589743

  16. Molecularly Imprinted Nanomaterials for Sensor Applications

    PubMed Central

    Irshad, Muhammad; Iqbal, Naseer; Mujahid, Adnan; Afzal, Adeel; Hussain, Tajamal; Sharif, Ahsan; Ahmad, Ejaz; Athar, Muhammad Makshoof

    2013-01-01

    Molecular imprinting is a well-established technology to mimic antibody-antigen interaction in a synthetic platform. Molecularly imprinted polymers and nanomaterials usually possess outstanding recognition capabilities. Imprinted nanostructured materials are characterized by their small sizes, large reactive surface area and, most importantly, with rapid and specific analysis of analytes due to the formation of template driven recognition cavities within the matrix. The excellent recognition and selectivity offered by this class of materials towards a target analyte have found applications in many areas, such as separation science, analysis of organic pollutants in water, environmental analysis of trace gases, chemical or biological sensors, biochemical assays, fabricating artificial receptors, nanotechnology, etc. We present here a concise overview and recent developments in nanostructured imprinted materials with respect to various sensor systems, e.g., electrochemical, optical and mass sensitive, etc. Finally, in light of recent studies, we conclude the article with future perspectives and foreseen applications of imprinted nanomaterials in chemical sensors. PMID:28348356

  17. Astrobiological Molecularly Imprinted Polymer Sensors

    NASA Astrophysics Data System (ADS)

    Izenberg, N. R.; Murray, G. M.; van Houten, K. A.; Hofstra, A. A.

    2005-12-01

    Development of Molecularly Imprinted Polymer (MIP) sensors for astrobiology is intended to provide a new class of microlaboratory sensors compatible with other life or biomarker detection. Molecular imprinting is a process for making selective binding sites in synthetic polymers. The process may be approached by designing the recognition site or by simply choosing monomers that may have favorable interactions with the imprinting molecule. We are working to apply this methodology to astrobiology for development of a reliable, low cost, low mass, low power consumption sensor technology for quantitative in-situ analysis of biochemistry, biomarkers, and other indicators of astrobiological importance. Specific goals of the project are: 1) To develop a general methodology and specific methods for MIP-based sensor construction. The overall methodology will guide procedures for design and testing of any desired sensor. Specific methods will be applied to key families and specific species of astrobiological interest, i.e., alkanes (and Polycyclic aromatic hydrocarbons - PAHs), amino acids, steroids, and hopanes; 2) To construct and characterize the general family and specific species sensors. We will test for accuracy, precision, interferences, and limitations of the sensor against blanks, standards, and known terrestrial biological environment samples. Additional testing will determine sturdiness and longevity of sensors after exposure to transit conditions (launch and space environment), and at potential target environments (pressure, temperature, pH, etc.); and 3) To construct and demonstrate the combination of multiple sensors into a viable prototype instrument, and roadmap the expansion of potential instrument capabilities and exploration of the ultimate environmental limitations of the technology, and the necessary changes and additions to create a mission-ready instrument. Initial work has resulted successful detection of aqueous alanine (D and L) with simple MIP

  18. Neurodevelopmental disorders involving genomic imprinting at human chromosome 15q11-q13.

    PubMed

    Chamberlain, Stormy J; Lalande, Marc

    2010-07-01

    Human chromosome 15q11-q13 is subject to regulation by genomic imprinting, an epigenetic process by which genes are expressed in a parent-of-origin specific manner. Three neurodevelopmental disorders, Prader-Willi syndrome, Angelman syndrome, and 15q duplication syndrome, result from aberrant expression of imprinted genes in this region. Here, we review the current literature pertaining to mouse models and recently identified patients with atypical deletions, which shed light on the epigenetic regulation of the chromosome 15q11-q13 subregion and the genes that are responsible for the phenotypic outcomes of these disorders.

  19. 21 CFR 206.10 - Code imprint required.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 4 2010-04-01 2010-04-01 false Code imprint required. 206.10 Section 206.10 Food...: GENERAL IMPRINTING OF SOLID ORAL DOSAGE FORM DRUG PRODUCTS FOR HUMAN USE § 206.10 Code imprint required... delivered for introduction into interstate commerce unless it is clearly marked or imprinted with a...

  20. Associations Between Fetal Imprinted Genes and Maternal Blood Pressure in Pregnancy.

    PubMed

    Petry, Clive J; Sanz Marcos, Nuria; Pimentel, Gracielle; Hayes, M Geoffrey; Nodzenski, Michael; Scholtens, Denise M; Hughes, Ieuan A; Acerini, Carlo L; Ong, Ken K; Lowe, William L; Dunger, David B

    2016-12-01

    In addition to maternal genes and environmental exposures, variation in fetal imprinted genes could also affect maternal blood pressure during pregnancy. Our objective was to test the associations between polymorphic variants in 16 imprinted genes and maternal mean arterial blood pressures in 1160 DNA trios from 2 established birth cohorts (the Cambridge Baby Growth and Wellbeing Studies) and seek replication in 1367 Hyperglycemia and Adverse Pregnancy Outcome Study participants. Significant univariate associations, all independent of fetal sex, were observed in the Cambridge cohorts, including FAM99A rs1489945 transmitted from the mother (P=2×10(-4)), DLK1 rs10139403 (mother; P=9×10(-4)), DLK1 rs12147008 (mother; P=1×10(-3)), H19 rs217222 (father; P=1×10(-3)), SNRPN rs1453556 (father; P=1×10(-3)), IGF2 rs6356 (father; P=1×10(-3)), and NNAT rs6066671 (father; P=1×10(-3)). In meta-analysis including additional independent Hyperglycemia and Adverse Pregnancy Outcome Study data, the association with maternally transmitted fetal DLK1 rs10139403 reached genome-wide significance (P=6.3×10(-10)). With the exception of fetal rs1489945 and rs217222, all of other associations were unidirectional and most were statistically significant. To further explore the significance of these relationships, we developed an allele score based on the univariate findings. The score was strongly associated with maternal blood pressure at 31 weeks (P=4.1×10(-8); adjusted r(2)=5.6%) and 37 weeks of pregnancy (P=1.1×10(-4); r(2)=3.6%), and during the last 2 weeks before parturition (P=1.1×10(-10); r(2)=8.7%). It was also associated with gestational hypertension (odds ratio, 1.54 [range, 1.14-2.09] per allele; P=0.005; 45 cases and 549 controls). These data support the concept that fetal imprinted genes are related to the development of gestational hypertension.

  1. No Evidence for Enrichment in Schizophrenia for Common Allelic Associations at Imprinted Loci

    PubMed Central

    Escott-Price, Valentina; Kirov, George; Rees, Elliott; Isles, Anthony R.; Owen, Michael J.; O’Donovan, Michael C.

    2015-01-01

    Most genetic studies assume that the function of a genetic variant is independent of the parent from which it is inherited, but this is not always true. The best known example of parent-of-origin effects arises with respect to alleles at imprinted loci. In classical imprinting, characteristically, either the maternal or paternal copy is expressed, but not both. Only alleles present in one of the parental copies of the gene, the expressed copy, is likely to contribute to disease. It has been postulated that imprinting is important in central nervous system development, and that consequently, imprinted loci may be involved in schizophrenia. If this is true, allowing for parent-of-origin effects might be important in genetic studies of schizophrenia. Here, we use genome-wide association data from one of the world’s largest samples (N = 695) of parent schizophrenia-offspring trios to test for parent-of-origin effects. To maximise power, we restricted our analyses to test two main hypotheses. If imprinting plays a disproportionate role in schizophrenia susceptibility, we postulated a) that alleles showing robust evidence for association to schizophrenia from previous genome-wide association studies should be enriched for parent-of-origin effects and b) that genes at loci imprinted in humans or mice should be enriched both for genome-wide significant associations, and in our sample, for parent-of-origin effects. Neither prediction was supported in the present study. We have shown, that it is unlikely that parent-of-origin effects or imprinting play particularly important roles in schizophrenia, although our findings do not exclude such effects at specific loci nor do they exclude such effects among rare alleles. PMID:26633303

  2. At Least Ten Genes Define the Imprinted Dlk1-Dio3 Cluster on Mouse Chromosome 12qF1

    PubMed Central

    Hagan, John P.; O'Neill, Brittany L.; Stewart, Colin L.; Kozlov, Serguei V.; Croce, Carlo M.

    2009-01-01

    Background Genomic imprinting is an exception to Mendelian genetics in that imprinted genes are expressed monoallelically, dependent on parental origin. In mammals, imprinted genes are critical in numerous developmental and physiological processes. Aberrant imprinted gene expression is implicated in several diseases including Prader-Willi/Angelman syndromes and cancer. Methodology/Principal Findings To identify novel imprinted genes, transcription profiling was performed on two uniparentally derived cell lines, androgenetic and parthenogenetic primary mouse embryonic fibroblasts. A maternally expressed transcript termed Imprinted RNA near Meg3/Gtl2 (Irm) was identified and its expression studied by Northern blotting and whole mounts in situ hybridization. The imprinted region that contains Irm has a parent of origin effect in three mammalian species, including the sheep callipyge locus. In mice and humans, both maternal and paternal uniparental disomies (UPD) cause embryonic growth and musculoskeletal abnormalities, indicating that both alleles likely express essential genes. To catalog all imprinted genes in this chromosomal region, twenty-five mouse mRNAs in a 1.96Mb span were investigated for allele specific expression. Conclusions/Significance Ten imprinted genes were elucidated. The imprinting of three paternally expressed protein coding genes (Dlk1, Peg11, and Dio3) was confirmed. Seven noncoding RNAs (Meg3/Gtl2, Anti-Peg11, Meg8, Irm/“Rian”, AK050713, AK053394, and Meg9/Mirg) are characterized by exclusive maternal expression. Intriguingly, the majority of these noncoding RNA genes contain microRNAs and/or snoRNAs within their introns, as do their human orthologs. Of the 52 identified microRNAs that map to this region, six are predicted to regulate negatively Dlk1, suggesting an additional mechanism for interactions between allelic gene products. Since several previous studies relied heavily on in silico analysis and RT-PCR, our findings from Northerns

  3. Parental and sexual conflicts over the Peg3 imprinted domain

    PubMed Central

    He, Hongzhi; Perera, Bambarendage P. U.; Ye, An; Kim, Joomyeong

    2016-01-01

    In the current study, the imprinting control region of the mouse Peg3 domain was deleted to test its functional impact on animal growth and survival. The paternal transmission of the deletion resulted in complete abolition of the transcription of two paternally expressed genes, Peg3 and Usp29, causing the reduced body weight of the pups. In contrast, the maternal transmission resulted in the unexpected transcriptional up-regulation of the remaining paternal allele of both Peg3 and Usp29, causing the increased body weight and survival rates. Thus, the imprinted maternal allele of the ICR may be a suppressor antagonistic to the active paternal allele of the ICR, suggesting a potential intralocus allelic conflict. The opposite outcomes between the two transmissions also justify the functional compromise that the maternal allele has become epigenetically repressed rather than genetically deleted during mammalian evolution. The mice homozygous for the deletion develop normally but with a skewed sex ratio, one male per litter, revealing its sex-biased effect. Overall, the Peg3 locus may have evolved to an imprinted domain to cope with both parental and sexual conflicts driven by its growth-stimulating paternal versus growth-suppressing maternal alleles. PMID:27901122

  4. Joint analysis of additive, dominant and first-order epistatic effects of four genes (IGF2, MC4R, PRKAG3 and LEPR) with known effects on fat content and fat distribution in pigs.

    PubMed

    López-Buesa, P; Burgos, C; Galve, A; Varona, L

    2014-02-01

    LEPR, MC4R, IGF2 and PRKAG3 are genes with known effects on fat content and distribution in pig carcass and pork. In a study performed with Duroc × Landrace/Large White pigs, we have found that IGF2 has strong additive effects on several carcass conformational traits and on fatty acid composition in several anatomical locations. MC4R shows additive effects on saturated fatty acid content in several muscles. On the other side, almost no additive effect has been found for PRKAG3 and very few for LEPR. In this work, no dominant effect has been found for any of the four genes. Using a Bayesian Lasso approach, we have been able now to find first-order epistatic (mainly dominant-additive) effects between LEPR and PRKAG3 for intramuscular fat content and for saturated fatty acid content in L. dorsii, B. femoralis, Ps. major and whole ham. The presence of interactions between genes in the shaping of traits of such importance as intramuscular fat content and composition highlights the complexity of heritable traits and the difficulty of gene-assisted selection for such traits.

  5. Matrisibs, Patrisibs, and the Evolution of Imprinting on Autosomes and Sex Chromosomes

    PubMed Central

    Brandvain, Yaniv

    2011-01-01

    The conflict theory of genomic imprinting argues that parent-of-origin effects on allelic expression evolve as a consequence of conflict between maternally and paternally derived genomes. I derive explicit population-genetic models of this theory when individuals in a cohort with an arbitrary and variable number of sires and dams interact. I show that the evolution of imprinting is governed by the reciprocal of the harmonic mean number of fathers but the reciprocal of the arithmetic mean number of mothers per cohort. Thus, a few monandrous females in a polyandrous population decrease the strength of the genetic conflict and the opportunity for conflict-driven paternal imprinting. In contrast, in populations in which few males control large harems, rare males with small harems do not have such a disproportionate effect on genetic conflicts and maternal imprinting. Additionally, I demonstrate that under the conflict theory, selection for imprinted expression on paternally derived X chromosomes is much weaker than it is on maternally derived X chromosomes or autosomes. PMID:20795831

  6. Molecular imprinting of bulk, microporous silica

    NASA Astrophysics Data System (ADS)

    Katz, Alexander; Davis, Mark E.

    2000-01-01

    Molecular imprinting aims to create solid materials containing chemical functionalities that are spatially organized by covalent or non-covalent interactions with imprint (or template) molecules during the synthesis process. Subsequent removal of the imprint molecules leaves behind designed sites for the recognition of small molecules, making the material ideally suited for applications such as separations, chemical sensing and catalysis. Until now, the molecular imprinting of bulk polymers and polymer and silica surfaces has been reported, but the extension of these methods to a wider range of materials remains problematic. For example, the formation of substrate-specific cavities within bulk silica, while conceptually straightforward, has been difficult to accomplish experimentally. Here we describe the imprinting of bulk amorphous silicas with single aromatic rings carrying up to three 3-aminopropyltriethoxysilane side groups; this generates and occupies microporosity and attaches functional organic groups to the pore walls in a controlled fashion. The triethoxysilane part of the molecules' side groups is incorporated into the silica framework during sol-gel synthesis, and subsequent removal of the aromatic core creates a cavity with spatially organized aminopropyl groups covalently anchored to the pore walls. We find that the imprinted silicas act as shape-selective base catalysts. Our strategy can be extended to imprint other functional groups, which should give access to a wide range of functionalized materials.

  7. Molecularly Imprinted Membranes: Past, Present, and Future.

    PubMed

    Yoshikawa, Masakazu; Tharpa, Kalsang; Dima, Ştefan-Ovidiu

    2016-10-12

    More than 80 years ago, artificial materials with molecular recognition sites emerged. The application of molecular imprinting to membrane separation has been studied since 1962. Especially after 1990, such research has been intensively conducted by membranologists and molecular imprinters to understand the advantages of each technique with the aim of constructing an ideal membrane, which is still an active area of research. The present review aims to be a substantial, comprehensive, authoritative, critical, and general-interest review, placed at the cross section of two broad, interconnected, practical, and extremely dynamic fields, namely, the fields of membrane separation and molecularly imprinted polymers. This review describes the recent discoveries that appeared after repeated and fertile collisions between these two fields in the past three years, to which are added the worthy acknowledgments of pioneering discoveries and a look into the future of molecularly imprinted membranes. The review begins with a general introduction in membrane separation, followed by a short theoretical section regarding the basic principles of mass transport through a membrane. Following these general aspects on membrane separation, two principles of obtaining polymeric materials with molecular recognition properties are reviewed, namely, molecular imprinting and alternative molecular imprinting, followed the methods of obtaining and practical applications for the particular case of molecularly imprinted membranes. The review continues with insights into molecularly imprinted nanofiber membranes as a promising, highly optimized type of membrane that could provide a relatively high throughput without a simultaneous unwanted reduction in permselectivity. Finally, potential applications of molecularly imprinted membranes in a variety of fields are highlighted, and a look into the future of membrane separations is offered.

  8. Mouse mutant embryos overexpressing IGF-II exhibit phenotypic features of the Beckwith–Wiedemann and Simpson–Golabi–Behmel syndromes

    PubMed Central

    Eggenschwiler, Jonathan; Ludwig, Thomas; Fisher, Peter; Leighton, Philip A.; Tilghman, Shirley M.; Efstratiadis, Argiris

    1997-01-01

    In mice, the imprinted Igf2 gene (expressed from the paternal allele), which encodes a growth-promoting factor (IGF-II), is linked closely to the reciprocally imprinted H19 locus on chromosome 7. Also imprinted (expressed from the maternal allele) is the Igf2r gene on chromsome 17 encoding the type 2 IGF receptor that is involved in degradation of excess IGF-II. Double mutant embryos carrying a deletion around the H19 region and also a targeted Igf2r allele, both inherited maternally, have extremely high levels of IGF-II (7- and 11-fold higher than normal in tissues and serum, respectively) as a result of biallelic Igf2 expression (imprint relaxation by deletion of H19-associated sequence) in combination with lack of the IGF2R-mediated IGF-II turnover. This excess of IGF-II causes somatic overgrowth, visceromegaly, placentomegaly, omphalocele, and cardiac and adrenal defects, which are also features of the Beckwith–Wiedemann syndrome (BWS), a genetically complex human disorder associated with chromosomal abnormalities in the 11p15.5 region where the IGF2 gene resides. In addition, the double mutant mouse embryos exhibit skeletal defects and cleft palate, which are manifestations observed frequently in the Simpson–Golabi–Behmel syndrome, another overgrowth disorder overlapping phenotypically, but not genetically, with BWS. PMID:9389646

  9. Insertion of an imprinted insulator into the IgH locus reveals developmentally regulated, transcription-dependent control of V(D)J recombination.

    PubMed

    Puget, Nadine; Hirasawa, Ryutaro; Hu, Ngoc-Sa Nguyen; Laviolette-Malirat, Nathalie; Feil, Robert; Khamlichi, Ahmed Amine

    2015-02-01

    The assembly of antigen receptor loci requires a developmentally regulated and lineage-specific recombination between variable (V), diversity (D), and joining (J) segments through V(D)J recombination. The process is regulated by accessibility control elements, including promoters, insulators, and enhancers. The IgH locus undergoes two recombination steps, D-J(H) and then V(H)-DJ(H), but it is unclear how the availability of the DJ(H) substrate could influence the subsequent V(H)-DJ(H) recombination step. The Eμ enhancer plays a critical role in V(D)J recombination and controls a set of sense and antisense transcripts. We epigenetically perturbed the early events at the IgH locus by inserting the imprinting control region (ICR) of the Igf2/H19 locus or a transcriptional insulator devoid of the imprinting function upstream of the Eμ enhancer. The insertions recapitulated the main epigenetic features of their endogenous counterparts, including differential DNA methylation and binding of CTCF/cohesins. Whereas the D-J(H) recombination step was unaffected, both the insulator insertions led to a severe impairment of V(H)-DJ(H) recombination. Strikingly, the inhibition of V(H)-DJ(H) recombination correlated consistently with a strong reduction of DJ(H) transcription and incomplete demethylation. Thus, developmentally regulated transcription following D-J(H) recombination emerges as an important mechanism through which the Eμ enhancer controls V(H)-DJ(H) recombination.

  10. Genomic Imprinting in the Endosperm Is Systematically Perturbed in Abortive Hybrid Tomato Seeds

    PubMed Central

    Florez-Rueda, Ana M.; Paris, Margot; Schmidt, Anja; Widmer, Alex; Grossniklaus, Ueli; Städler, Thomas

    2016-01-01

    Hybrid seed failure represents an important postzygotic barrier to interbreeding among species of wild tomatoes (Solanum section Lycopersicon) and other flowering plants. We studied genome-wide changes associated with hybrid seed abortion in the closely related Solanum peruvianum and S. chilense where hybrid crosses yield high proportions of inviable seeds due to endosperm failure and arrested embryo development. Based on differences of seed size in reciprocal hybrid crosses and developmental evidence implicating endosperm failure, we hypothesized that perturbed genomic imprinting is involved in this strong postzygotic barrier. Consequently, we surveyed the transcriptomes of developing endosperms from intra- and inter-specific crosses using tissues isolated by laser-assisted microdissection. We implemented a novel approach to estimate parent-of-origin–specific expression using both homozygous and heterozygous nucleotide differences between parental individuals and identified candidate imprinted genes. Importantly, we uncovered systematic shifts of “normal” (intraspecific) maternal:paternal transcript proportions in hybrid endosperms; the average maternal proportion of gene expression increased in both crossing directions but was stronger with S. peruvianum in the maternal role. These genome-wide shifts almost entirely eliminated paternally expressed imprinted genes in S. peruvianum hybrid endosperm but also affected maternally expressed imprinted genes and all other assessed genes. These profound, systematic changes in parental expression proportions suggest that core processes of transcriptional regulation are functionally compromised in hybrid endosperm and contribute to hybrid seed failure. PMID:27601611

  11. Genomic Imprinting in the Endosperm Is Systematically Perturbed in Abortive Hybrid Tomato Seeds.

    PubMed

    Florez-Rueda, Ana M; Paris, Margot; Schmidt, Anja; Widmer, Alex; Grossniklaus, Ueli; Städler, Thomas

    2016-11-01

    Hybrid seed failure represents an important postzygotic barrier to interbreeding among species of wild tomatoes (Solanum section Lycopersicon) and other flowering plants. We studied genome-wide changes associated with hybrid seed abortion in the closely related Solanum peruvianum and S. chilense where hybrid crosses yield high proportions of inviable seeds due to endosperm failure and arrested embryo development. Based on differences of seed size in reciprocal hybrid crosses and developmental evidence implicating endosperm failure, we hypothesized that perturbed genomic imprinting is involved in this strong postzygotic barrier. Consequently, we surveyed the transcriptomes of developing endosperms from intra- and inter-specific crosses using tissues isolated by laser-assisted microdissection. We implemented a novel approach to estimate parent-of-origin-specific expression using both homozygous and heterozygous nucleotide differences between parental individuals and identified candidate imprinted genes. Importantly, we uncovered systematic shifts of "normal" (intraspecific) maternal:paternal transcript proportions in hybrid endosperms; the average maternal proportion of gene expression increased in both crossing directions but was stronger with S. peruvianum in the maternal role. These genome-wide shifts almost entirely eliminated paternally expressed imprinted genes in S. peruvianum hybrid endosperm but also affected maternally expressed imprinted genes and all other assessed genes. These profound, systematic changes in parental expression proportions suggest that core processes of transcriptional regulation are functionally compromised in hybrid endosperm and contribute to hybrid seed failure.

  12. Ferroelectric capacitor with reduced imprint

    DOEpatents

    Evans, Jr., Joseph T.; Warren, William L.; Tuttle, Bruce A.; Dimos, Duane B.; Pike, Gordon E.

    1997-01-01

    An improved ferroelectric capacitor exhibiting reduced imprint effects in comparison to prior art capacitors. A capacitor according to the present invention includes top and bottom electrodes and a ferroelectric layer sandwiched between the top and bottom electrodes, the ferroelectric layer comprising a perovskite structure of the chemical composition ABO.sub.3 wherein the B-site comprises first and second elements and a dopant element that has an oxidation state greater than +4. The concentration of the dopant is sufficient to reduce shifts in the coercive voltage of the capacitor with time. In the preferred embodiment of the present invention, the ferroelectric element comprises Pb in the A-site, and the first and second elements are Zr and Ti, respectively. The preferred dopant is chosen from the group consisting of Niobium, Tantalum, and Tungsten. In the preferred embodiment of the present invention, the dopant occupies between 1 and 8% of the B-sites.

  13. Genomic imprinting-an epigenetic gene-regulatory model.

    PubMed

    Koerner, Martha V; Barlow, Denise P

    2010-04-01

    Epigenetic mechanisms (Box 1) are considered to play major gene-regulatory roles in development, differentiation and disease. However, the relative importance of epigenetics in defining the mammalian transcriptome in normal and disease states is unknown. The mammalian genome contains only a few model systems where epigenetic gene regulation has been shown to play a major role in transcriptional control. These model systems are important not only to investigate the biological function of known epigenetic modifications but also to identify new and unexpected epigenetic mechanisms in the mammalian genome. Here we review recent progress in understanding how epigenetic mechanisms control imprinted gene expression.

  14. Protein conformational studies for macromolecularly imprinted polymers.

    PubMed

    Kryscio, David R; Fleming, Michael Q; Peppas, Nicholas A

    2012-08-01

    CD is used to clearly show the negative impact of common ligands on the overall conformation of BSA, a typical protein template in macromolecularly imprinted polymers. This change occurs at concentrations far lower than those generally used in the literature. These findings are important as they offer insight into a potential fundamental reason for the lack of success in protein imprinting to date despite significant interest from the scientific community.

  15. Cellular functions of genetically imprinted genes in human and mouse as annotated in the gene ontology.

    PubMed

    Hamed, Mohamed; Ismael, Siba; Paulsen, Martina; Helms, Volkhard

    2012-01-01

    By analyzing the cellular functions of genetically imprinted genes as annotated in the Gene Ontology for human and mouse, we found that imprinted genes are often involved in developmental, transport and regulatory processes. In the human, paternally expressed genes are enriched in GO terms related to the development of organs and of anatomical structures. In the mouse, maternally expressed genes regulate cation transport as well as G-protein signaling processes. Furthermore, we investigated if imprinted genes are regulated by common transcription factors. We identified 25 TF families that showed an enrichment of binding sites in the set of imprinted genes in human and 40 TF families in mouse. In general, maternally and paternally expressed genes are not regulated by different transcription factors. The genes Nnat, Klf14, Blcap, Gnas and Ube3a contribute most to the enrichment of TF families. In the mouse, genes that are maternally expressed in placenta are enriched for AP1 binding sites. In the human, we found that these genes possessed binding sites for both, AP1 and SP1.

  16. Imprinting in the schizophrenia candidate gene GABRB2 encoding GABA(A) receptor β(2) subunit.

    PubMed

    Pun, F W; Zhao, C; Lo, W-S; Ng, S-K; Tsang, S-Y; Nimgaonkar, V; Chung, W S; Ungvari, G S; Xue, H

    2011-05-01

    Schizophrenia is a complex genetic disorder, the inheritance pattern of which is likely complicated by epigenetic factors yet to be elucidated. In this study, transmission disequilibrium tests with family trios yielded significant differences between paternal and maternal transmissions of the disease-associated single-nucleotide polymorphism (SNP) rs6556547 and its haplotypes. The minor allele (T) of rs6556547 was paternally undertransmitted to male schizophrenic offsprings, and this parent-of-origin effect strongly suggested that GABRB2 is imprinted. 'Flipping' of allelic expression in heterozygotes of SNP rs2229944 (C/T) in GABRB2 or rs2290732 (G/A) in the neighboring GABRA1 was compatible with imprinting effects on gene expression. Clustering analysis of GABRB2 mRNA expressions suggested that imprinting brought about the observed two-tiered distribution of expression levels in controls with heterozygous genotype at the disease-associated SNP rs1816071 (A/G). The deficit of upper-tiered expressions accounted for the lowered expression levels in the schizophrenic heterozygotes. The occurrence of a two-tiered distribution furnished support for imprinting, and also pointed to the necessity of differentiating between two kinds of heterozygotes of different parental origins in disease association studies on GABRB2. Bisulfite sequencing revealed hypermethylation in the neighborhood of SNP rs1816071, and methylation differences between controls and schizophrenia patients. Notably, the two schizophrenia-associated SNPs rs6556547 and rs1816071 overlapped with a CpG dinucleotide, thereby opening the possibility that CpG methylation status of these sites could have an impact on the risk of schizophrenia. Thus multiple lines of evidence pointed to the occurrence of imprinting in the GABRB2 gene and its possible role in the development of schizophrenia.

  17. Molecularly imprinted polymers: present and future prospective.

    PubMed

    Vasapollo, Giuseppe; Sole, Roberta Del; Mergola, Lucia; Lazzoi, Maria Rosaria; Scardino, Anna; Scorrano, Sonia; Mele, Giuseppe

    2011-01-01

    Molecular Imprinting Technology (MIT) is a technique to design artificial receptors with a predetermined selectivity and specificity for a given analyte, which can be used as ideal materials in various application fields. Molecularly Imprinted Polymers (MIPs), the polymeric matrices obtained using the imprinting technology, are robust molecular recognition elements able to mimic natural recognition entities, such as antibodies and biological receptors, useful to separate and analyze complicated samples such as biological fluids and environmental samples. The scope of this review is to provide a general overview on MIPs field discussing first general aspects in MIP preparation and then dealing with various application aspects. This review aims to outline the molecularly imprinted process and present a summary of principal application fields of molecularly imprinted polymers, focusing on chemical sensing, separation science, drug delivery and catalysis. Some significant aspects about preparation and application of the molecular imprinting polymers with examples taken from the recent literature will be discussed. Theoretical and experimental parameters for MIPs design in terms of the interaction between template and polymer functionalities will be considered and synthesis methods for the improvement of MIP recognition properties will also be presented.

  18. Fluorescence Anisotropy Studies of Molecularly Imprinted Polymers

    SciTech Connect

    Chen, Yin-Chu; Wang, Zheming; Yan, Mingdi; Prahl, Scott A.

    2006-01-01

    A molecularly imprinted polymer (MIP) is a biomimetic material that can be used as a biochemical sensing element. We studied the steady-state and time-resolved fluorescence and fluorescence anisotropy of anthracene imprinted polyurethane. We compared MIPs with imprinted analytes present, MIPs with the imprinted analytes extracted, MIPs with rebound analytes, non-imprinted control polymers (non-MIPs), and non-MIPs bound with analytes to understand MIP’s binding behavior. MIPs and non-MIPs had similar steady-state fluorescence anisotropy in the range of 0.11–0.24. Anthracene rebound in MIPs and non-MIPs had a fluorescence lifetime _=0.64 ns and a rotational correlation time _F =1.2–1.5 ns, both of which were shorter than that of MIPs with imprinted analytes present (_=2.03 ns and _F =2.7 ns). The steady-state anisotropy of polymer solutions increased exponentially with polymerization time and might be used to characterize the polymerization extent in-situ.

  19. Molecularly Imprinted Polymers: Present and Future Prospective

    PubMed Central

    Vasapollo, Giuseppe; Sole, Roberta Del; Mergola, Lucia; Lazzoi, Maria Rosaria; Scardino, Anna; Scorrano, Sonia; Mele, Giuseppe

    2011-01-01

    Molecular Imprinting Technology (MIT) is a technique to design artificial receptors with a predetermined selectivity and specificity for a given analyte, which can be used as ideal materials in various application fields. Molecularly Imprinted Polymers (MIPs), the polymeric matrices obtained using the imprinting technology, are robust molecular recognition elements able to mimic natural recognition entities, such as antibodies and biological receptors, useful to separate and analyze complicated samples such as biological fluids and environmental samples. The scope of this review is to provide a general overview on MIPs field discussing first general aspects in MIP preparation and then dealing with various application aspects. This review aims to outline the molecularly imprinted process and present a summary of principal application fields of molecularly imprinted polymers, focusing on chemical sensing, separation science, drug delivery and catalysis. Some significant aspects about preparation and application of the molecular imprinting polymers with examples taken from the recent literature will be discussed. Theoretical and experimental parameters for MIPs design in terms of the interaction between template and polymer functionalities will be considered and synthesis methods for the improvement of MIP recognition properties will also be presented. PMID:22016636

  20. A statistical design for testing transgenerational genomic imprinting in natural human populations.

    PubMed

    Li, Yao; Guo, Yunqian; Wang, Jianxin; Hou, Wei; Chang, Myron N; Liao, Duanping; Wu, Rongling

    2011-02-25

    Genomic imprinting is a phenomenon in which the same allele is expressed differently, depending on its parental origin. Such a phenomenon, also called the parent-of-origin effect, has been recognized to play a pivotal role in embryological development and pathogenesis in many species. Here we propose a statistical design for detecting imprinted loci that control quantitative traits based on a random set of three-generation families from a natural population in humans. This design provides a pathway for characterizing the effects of imprinted genes on a complex trait or disease at different generations and testing transgenerational changes of imprinted effects. The design is integrated with population and cytogenetic principles of gene segregation and transmission from a previous generation to next. The implementation of the EM algorithm within the design framework leads to the estimation of genetic parameters that define imprinted effects. A simulation study is used to investigate the statistical properties of the model and validate its utilization. This new design, coupled with increasingly used genome-wide association studies, should have an immediate implication for studying the genetic architecture of complex traits in humans.

  1. Cationic imprinting of Pb(II) within composite networks based on bovine or fish chondroitin sulfate.

    PubMed

    Ferreira, Vanessa R A; Azenha, Manuel A; Mêna, M Teresa; Moura, Cosme; Pereira, Carlos M; Pérez-Martín, Ricardo I; Vázquez, José A; Silva, A Fernando

    2017-02-03

    Imprinting chondroitin sulfate (CS)/silica composites with Pb(II) and Cu(II) cations was explored with CS of bovine and different fish species origin. The process was based on the assumption that particular arrangements of the linear CS chains in aqueous solution, induced so as to accommodate cross complexation with the cations, would be embodied into a tridimensional matrix created through an organoalkoxysilane sol-gel scheme. The presence of Cu(II) in the synthesis of the composites did not result in the production of significantly stronger Cu(II)-oriented binding arrangements, and therefore, the imprinting was not successful. Inversely, for Pb(II), the materials obtained exhibited a "memory" effect for the Pb(II) ions, expressed in the observation of stronger (13%-44%) binding as compared to the nonimprinted counterparts, and increased selectivity (1.5-2 folds) against Cd(II). The imprinting features observed were dependent on the CS source. However, it was not possible to identify, among a set of their properties (carboxylate and sulfate abundance, percent of disulfated units, 4S/6S ratio, and molecular weight), any that correlated directly with the observed imprinting features. The augmented selectivity provided by the cation-imprinting process may be advantageous in areas such as analytical separation, remediation, purification, sensing, and others, particularly in those cases where a certain cation is of special interest within a mixture of them.

  2. Imprinting mutations suggested by abnormal DNA methylation patterns in familial Angelman and Prader-Willi syndromes.

    PubMed Central

    Reis, A.; Dittrich, B.; Greger, V.; Buiting, K.; Lalande, M.; Gillessen-Kaesbach, G.; Anvret, M.; Horsthemke, B.

    1994-01-01

    The D15S9 and D15S63 loci in the Prader-Willi/Angelman syndrome region on chromosome 15 are subject to parent-of-origin-specific DNA methylation. We have found two Prader-Willi syndrome families in which the patients carry a maternal methylation imprint on the paternal chromosome. In one of these families, the patients have a small deletion encompassing the gene for the small nuclear ribonucleoprotein polypeptide N, which maps 130 kb telomeric to D15S63. Furthermore, we have identified a pair of nondeletion Angelman syndrome sibs and two isolated Angelman syndrome patients who carry a paternal methylation imprint on the maternal chromosome. These Angelman and Prader-Willi syndrome patients may have a defect in the imprinting process in 15q11-13. We propose a model in which a cis-acting mutation prevents the resetting of the imprinting signal in the germ line and thus disturbs the expression of imprinted genes in this region. Images Figure 2 Figure 3 PMID:8178815

  3. Imprinting mutations suggested by abnormal DNA methylation patterns in familial angelman and Prader-Willi syndromes

    SciTech Connect

    Reis, A. ); Dittrich, B.; Buiting, K.; Gillessen-Kaesbach, G.; Horsthemke, B. ); Greger, V.; Lalande, M. ); Anvret, M. )

    1994-05-01

    The D15S9 and D15S63 loci in the Prader-Willi/Angelman syndrome region on chromosome 15 are subject to parent-of-origin-specific DNA methylation. The authors have found two Prader-Willi syndrome families in which the patients carry a maternal methylation imprint on the paternal chromosome. In one of these families, the patients have a small deletion encompassing the gene for the small nuclear ribonucleoprotein polypeptide N, which maps 130 kb telomeric to D15S63. Furthermore, they have identified a pair of nondeletion Angelman syndrome sibs and two isolated Angelman syndrome patients who carry a paternal methylation imprint on the maternal chromosome. These Angelman and Prader-Willi syndrome patients may have a defect in the imprinting process in 15q11-13. The authors propose a model in which a cis-acting mutation prevents the resetting of the imprinting signal in the germ line and thus disturbs the expression of imprinted genes in this region. 39 refs., 4 figs., 1 tab.

  4. A novel approach identifies new differentially methylated regions (DMRs) associated with imprinted genes

    PubMed Central

    Choufani, Sanaa; Shapiro, Jonathan S.; Susiarjo, Martha; Butcher, Darci T.; Grafodatskaya, Daria; Lou, Youliang; Ferreira, Jose C.; Pinto, Dalila; Scherer, Stephen W.; Shaffer, Lisa G.; Coullin, Philippe; Caniggia, Isabella; Beyene, Joseph; Slim, Rima; Bartolomei, Marisa S.; Weksberg, Rosanna

    2011-01-01

    Imprinted genes are critical for normal human growth and neurodevelopment. They are characterized by differentially methylated regions (DMRs) of DNA that confer parent of origin-specific transcription. We developed a new strategy to identify imprinted gene-associated DMRs. Using genome-wide methylation profiling of sodium bisulfite modified DNA from normal human tissues of biparental origin, candidate DMRs were identified by selecting CpGs with methylation levels consistent with putative allelic differential methylation. In parallel, the methylation profiles of tissues of uniparental origin, i.e., paternally-derived androgenetic complete hydatidiform moles (AnCHMs), and maternally-derived mature cystic ovarian teratoma (MCT), were examined and then used to identify CpGs with parent of origin-specific DNA methylation. With this approach, we found known DMRs associated with imprinted genomic regions as well as new DMRs for known imprinted genes, NAP1L5 and ZNF597, and novel candidate imprinted genes. The paternally methylated DMR for one candidate, AXL, a receptor tyrosine kinase, was also validated in experiments with mouse embryos that demonstrated Axl was expressed preferentially from the maternal allele in a DNA methylation-dependent manner. PMID:21324877

  5. X-inactivation, imprinting, and long noncoding RNAs in health and disease.

    PubMed

    Lee, Jeannie T; Bartolomei, Marisa S

    2013-03-14

    X chromosome inactivation and genomic imprinting are classic epigenetic processes that cause disease when not appropriately regulated in mammals. Whereas X chromosome inactivation evolved to solve the problem of gene dosage, the purpose of genomic imprinting remains controversial. Nevertheless, the two phenomena are united by allelic control of large gene clusters, such that only one copy of a gene is expressed in every cell. Allelic regulation poses significant challenges because it requires coordinated long-range control in cis and stable propagation over time. Long noncoding RNAs have emerged as a common theme, and their contributions to diseases of imprinting and the X chromosome have become apparent. Here, we review recent advances in basic biology, the connections to disease, and preview potential therapeutic strategies for future development.

  6. Molecular Imprinting Techniques Used for the Preparation of Biosensors.

    PubMed

    Ertürk, Gizem; Mattiasson, Bo

    2017-02-04

    Molecular imprinting is the technology of creating artificial recognition sites in polymeric matrices which are complementary to the template in their size, shape and spatial arrangement of the functional groups. Molecularly imprinted polymers (MIPs) and their incorporation with various transducer platforms are among the most promising approaches for detection of several analytes. There are a variety of molecular imprinting techniques used for the preparation of biomimetic sensors including bulk imprinting, surface imprinting (soft lithography, template immobilization, grafting, emulsion polymerization) and epitope imprinting. This chapter presents an overview of all of these techniques with examples from particular publications.

  7. Molecular Imprinting Techniques Used for the Preparation of Biosensors

    PubMed Central

    Ertürk, Gizem; Mattiasson, Bo

    2017-01-01

    Molecular imprinting is the technology of creating artificial recognition sites in polymeric matrices which are complementary to the template in their size, shape and spatial arrangement of the functional groups. Molecularly imprinted polymers (MIPs) and their incorporation with various transducer platforms are among the most promising approaches for detection of several analytes. There are a variety of molecular imprinting techniques used for the preparation of biomimetic sensors including bulk imprinting, surface imprinting (soft lithography, template immobilization, grafting, emulsion polymerization) and epitope imprinting. This chapter presents an overview of all of these techniques with examples from particular publications. PMID:28165419

  8. Erythrocyte folate concentrations, CpG methylation at genomically imprinted domains, and birth weight in a multiethnic newborn cohort.

    PubMed

    Hoyo, Cathrine; Daltveit, Anne Kjersti; Iversen, Edwin; Benjamin-Neelon, Sara E; Fuemmeler, Bernard; Schildkraut, Joellen; Murtha, Amy P; Overcash, Francine; Vidal, Adriana C; Wang, Frances; Huang, Zhiqing; Kurtzberg, Joanne; Seewaldt, Victoria; Forman, Michele; Jirtle, Randy L; Murphy, Susan K

    2014-08-01

    Epigenetic mechanisms are proposed to link maternal concentrations of methyl group donor nutrients with the risk of low birth weight. However, empirical data are lacking. We have examined the association between maternal folate and birth weight and assessed the mediating role of DNA methylation at nine differentially methylated regions (DMRs) of genomically imprinted genes in these associations. Compared with newborns of women with folate levels in the lowest quartile, birth weight was higher in newborns of mothers in the second (β = 143.2, se = 63.2, P = 0.02), third (β = 117.3, se = 64.0, P = 0.07), and fourth (β = 133.9, se = 65.2, P = 0.04) quartiles, consistent with a threshold effect. This pattern of association did not vary by race/ethnicity but was more apparent in newborns of non-obese women. DNA methylation at the PLAGL1, SGCE, DLK1/MEG3 and IGF2/H19 DMRs was associated with maternal folate levels and also birth weight, suggestive of threshold effects. MEG3 DMR methylation mediated the association between maternal folate levels and birth weight (P =0.06). While the small sample size and partial scope of examined DMRs limit our conclusions, our data suggest that, with respect to birth weight, no additional benefits may be derived from increased maternal folate concentrations, especially in non-obese women. These data also support epigenetic plasticity as a key mechanistic response to folate availability during early fetal development.

  9. Erythrocyte folate concentrations, CpG methylation at genomically imprinted domains, and birth weight in a multiethnic newborn cohort

    PubMed Central

    Hoyo, Cathrine; Daltveit, Anne Kjersti; Iversen, Edwin; Benjamin-Neelon, Sara E; Fuemmeler, Bernard; Schildkraut, Joellen; Murtha, Amy P; Overcash, Francine; Vidal, Adriana C; Wang, Frances; Huang, Zhiqing; Kurtzberg, Joanne; Seewaldt, Victoria; Forman, Michele; Jirtle, Randy L; Murphy, Susan K

    2014-01-01

    Epigenetic mechanisms are proposed to link maternal concentrations of methyl group donor nutrients with the risk of low birth weight. However, empirical data are lacking. We have examined the association between maternal folate and birth weight and assessed the mediating role of DNA methylation at nine differentially methylated regions (DMRs) of genomically imprinted genes in these associations. Compared with newborns of women with folate levels in the lowest quartile, birth weight was higher in newborns of mothers in the second (β = 143.2, se = 63.2, P = 0.02), third (β = 117.3, se = 64.0, P = 0.07), and fourth (β = 133.9, se = 65.2, P = 0.04) quartiles, consistent with a threshold effect. This pattern of association did not vary by race/ethnicity but was more apparent in newborns of non-obese women. DNA methylation at the PLAGL1, SGCE, DLK1/MEG3 and IGF2/H19 DMRs was associated with maternal folate levels and also birth weight, suggestive of threshold effects. MEG3 DMR methylation mediated the association between maternal folate levels and birth weight (P =0.06). While the small sample size and partial scope of examined DMRs limit our conclusions, our data suggest that, with respect to birth weight, no additional benefits may be derived from increased maternal folate concentrations, especially in non-obese women. These data also support epigenetic plasticity as a key mechanistic response to folate availability during early fetal development. PMID:24874916

  10. Evolution of mate-choice imprinting: competing strategies.

    PubMed

    Tramm, Nora A; Servedio, Maria R

    2008-08-01

    Mate-choice imprinting, the determination of mating preferences at an early age based on an individual's observation of adults, plays a role in mate choice in a wide variety of animals. Theoretical work has thus far been focused either on the effects of mate-choice imprinting on the evolution of the male trait used as a mating cue, or on the evolution of imprinting against a nonimprinting background. We ask the question: if multiple types of imprinting are possible in a species, which is likely to evolve? We develop a haploid population genetic model to compare the evolution of three forms of imprinting: paternal, maternal, and oblique (nonparental adult) imprinting. We find that paternal imprinting is the most likely to evolve, whereas maternal and oblique are nearly equivalent. We identify two factors that determine a strategy's success: its "imprinting set," the set of individuals imprinted upon, and phenogenotypic disequilibrium, the association between imprinted preferences and mating cues. We assess the predictive power of these factors, and find that the imprinting set is the primary determinant of a strategy's success. We suggest that the imprinting set concept may be generalized to predict the success of additional imprinting strategies, such as mate-choice copying.

  11. Differential methylation persists at the mouse Rasgrf1 DMR in tissues displaying monoallelic and biallelic expression.

    PubMed

    Dockery, Lauren; Gerfen, Jennifer; Harview, Christina; Rahn-Lee, Charlotte; Horton, Rachel; Park, Yaena; Davis, Tamara L

    2009-05-16

    A subset of mammalian genes exhibits genomic imprinting, whereby one parental allele is preferentially expressed. Differential DNA methylation at imprinted loci serves both to mark the parental origin of the alleles and to regulate their expression. In mouse, the imprinted gene Rasgrf1 is associated with a paternally methylated imprinting control region which functions as an enhancer blocker in its unmethylated state. Because Rasgrf1 is imprinted in a tissue-specific manner, we investigated the methylation pattern in monoallelic and biallelic tissues to determine if methylation of this region is required for both imprinted and non-imprinted expression. Our analysis indicates that DNA methylation is restricted to the paternal allele in both monoallelic and biallelic tissues of somatic and extraembryonic lineages. Therefore, methylation serves to mark the paternal Rasgrf1 allele throughout development, but additional factors are required for appropriate tissue-specific regulation of expression at this locus.

  12. Astrobiological molecularly imprinted polymer sensors

    NASA Astrophysics Data System (ADS)

    Izenberg, Noam R.; Murrray, George M.; Pilato, Robert S.; Baird, Lance M.; Levin, Scott M.; Van Houten, Kelly A.

    2009-06-01

    The purpose of the Astrobiological MIP Sensor (AMS) Project is to develop reliable, low-cost, low-mass, low-power consumption detection technologies for in situ analysis of biochemical markers, and other indicators of astrobiological importance. To this end, we are investigating the potential role that molecularly imprinted polymers (MIP) could serve in the recognition of pre-biotic and biotic compounds in planetary, astrobiological and geochemical mission profiles. While MIPs are effective molecular recognition tools, a signal transduction method must be developed so that the recognition of analytes can be realized. In the course of this study, surface plasmon resonance (SPR) will be the detection method of the MIP recognition event. In addition, MIP-coated SPR substrates were subjected to vibration, temperature and radiation testing to demonstrate that they could withstand the rigors of space travel. The methods developed in this study require capture of the biomarkers onto the SPR sensor chip, followed by addition of a MIP. It is the binding of the MIP to the SPR bound analyte that amplifies the SPR signal associated with binding of the low molecular weight analyte. The MIPs, developed in this study are water-soluble processable star polymers while the SPR device used was SensíQ™ by Nomatics. Proof-of-principal experiments were first demonstrated using amino biotin.

  13. The Regulation of Non-Coding RNA Expression in the Liver of Mice Fed DDC

    PubMed Central

    Oliva, Joan; Bardag-Gorce, Fawzia; French, Barbara A; Li, Jun; French, Samuel W

    2010-01-01

    Mallory-Denk bodies (MDBs) are found in the liver of patients with alcoholic and chronic nonalcoholic liver disease, and hepatocellular carcinoma (HCC). Diethyl 1,4-dihydro-2,4,6,-trimethyl-3,5-pyridinedicarboxylate (DDC) is used as a model to induce the formation of MDBs in mouse liver. Previous studies in this laboratory showed that DDC induced epigenetic modifications in DNA and histones. The combination of these modifications changes the phenotype of the MDB forming hepatocytes, as indicated by the marker FAT10. These epigenetic modifications are partially prevented by adding to the diet S-adenosylmethionine (SAMe) or betaine, both methyl donors. The expression of three imprinted ncRNA genes was found to change in MDB forming hepatocytes, which is the subject of this report. NcRNA expression was quantitated by Real-Time PCR and RNA FISH in liver sections. Microarray analysis showed that the expression of three ncRNAs was regulated by DDC: up regulation of H19, antisense Igf2r (AIR), and down regulation of GTL2 (also called MEG3). S-adenosylmethionine (SAMe) feeding prevented these changes. Betaine, another methyl group donor, prevented only H19 and AIR up regulation induced by DDC, on microarrays. The results of the SAMe and betaine groups were confirmed by Real-Time PCR, except for AIR expression. After 1 month of drug withdrawal, the expression of the three ncRNAs tended toward control levels of expression. Liver tumors that developed also showed up regulation of H19 and AIR. The RNA FISH approach showed that the MDB forming cells’ phenotype changed the level of expression of AIR, H19 and GTL2, compared to the surrounding cells. Furthermore, over expression of H19 and AIR was demonstrated in tumors formed in mice withdrawn for 9 months. The disregulation of ncRNA in MDB forming liver cells has been observed for the first time in drug primed mice associated with liver preneoplastic foci and tumors. PMID:19362547

  14. The conflict theory of genomic imprinting: how much can be explained?

    PubMed

    Iwasa, Y

    1998-01-01

    In some mammalian genes, paternally and maternally derived alleles are expressed differently: this phenomenon is called genomic imprinting. Several-explanations have been proposed for the observed patterns of genomic imprinting, but the most successful explanation is the genetic conflict hypothesis--natural selection operating on the gene expression produces the parental origin-dependent gene expression--because the paternally derived allele tends to be less related to the siblings of the same mother than the maternal allele and hence the paternal allele should evolve to be more aggressive in obtaining maternal resources. The successes and failures of this argument have been examined in explaining the observed patterns of genomic imprinting in mammals. After a brief summary of the observations with some examples, a quantitative genetic model describing the evolution of the cis-regulating element of a gene affecting the maternal resource acquisition was presented. The model supports the verbal argument that the growth enhancer should evolve to show imprinting with the paternal allele expressed and the maternal allele inactive, whereas a growth suppressor gene tends to have an inactive paternal allele and an active maternal allele. There are four major problems of the genetic conflict hypothesis. (1) Some genes affect embryonic growth but are not imprinted (e.g., Igf1), which can be explained by considering recessive, deleterious mutations on the coding regions, (2) A gene exists that shows the pattern that is a perfect reversal (Mash2), which is needed for placental growth, and yet has an active maternal allele and an inactive paternal allele. This can be explained if the overproduction of this gene causes dose-sensitive abortion to occur in early gestation. (3) Paternal disomies are sometimes smaller than normal embryos. This is a likely outcome of evolution if imprinted genes control the allocation between placenta and embryo by modifying the cell developmental

  15. Molecularly imprinted polymers for biomedical and biotechnological applications

    NASA Astrophysics Data System (ADS)

    Dmitrienko, E. V.; Pyshnaya, I. A.; Martyanov, O. N.; Pyshnyi, D. V.

    2016-05-01

    This survey covers main advances in the preparation and application of molecularly imprinted polymers which are capable of specific recognition of biologically active compounds. The principles underlying the production of highly efficient and template-specific molecularly imprinted polymers are discussed. The focus is on the imprinting of highly structured macromolecular and supramolecular templates. The existing and potential applications of molecularly imprinted polymers in various fields of chemistry and molecular biology are considered. The bibliography includes 261 references.

  16. Monolithic molecularly imprinted cryogel for lysozyme recognition.

    PubMed

    Rabieizadeh, Mohammadmahdi; Kashefimofrad, Seyed Mohammadreza; Naeimpoor, Fereshteh

    2014-10-01

    The application of molecularly imprinted polymers in the selective adsorption of macromolecules such as proteins by monolithic protein-imprinted columns requires a macroporous structure, which can be provided by cryogelation at low temperature in which the formation of ice crystals gives a porous structure to the molecularly imprinted polymer. In this study, we applied this technique to synthesize lysozyme-imprinted polyacrylamide cryogels containing 8% w/v of total monomers and 0.3% w/v of lysozyme. The synthesized cryogel was sponge-like and elastic with very fast swelling and reshaping properties, showing a swelling ratio of 24.5 ± 3 and gel fraction yield of about 72%. It showed an imprinting effect of 1.58 and a separation factor of 1.37 for cytochrome c as the competing protein. Adsorption studies on the cryogel revealed that it follows the Langmuir isotherm, with a maximum theoretical adsorption capacity of 36.3 mg lysozyme per gram of cryogel. Additionally, it was shown that a salt-free rebinding solution at low flow rate and pH = 7.0 is favorable for lysozyme rebinding. This kind of monolithic column promises a wide range of application in separation of various biomolecules due to its preparation simplicity, good rebinding characteristics, and macroporosity.

  17. Causal Imprinting in Causal Structure Learning

    PubMed Central

    Taylor, Eric G.; Ahn, Woo-kyoung

    2012-01-01

    Suppose one observes a correlation between two events, B and C, and infers that B causes C. Later one discovers that event A explains away the correlation between B and C. Normatively, one should now dismiss or weaken the belief that B causes C. Nonetheless, participants in the current study who observed a positive contingency between B and C followed by evidence that B and C were independent given A, persisted in believing that B causes C. The authors term this difficulty in revising initially learned causal structures “causal imprinting.” Throughout four experiments, causal imprinting was obtained using multiple dependent measures and control conditions. A Bayesian analysis showed that causal imprinting may be normative under some conditions, but causal imprinting also occurred in the current study when it was clearly non-normative. It is suggested that causal imprinting occurs due to the influence of prior knowledge on how reasoners interpret later evidence. Consistent with this view, when participants first viewed the evidence showing that B and C are independent given A, later evidence with only B and C did not lead to the belief that B causes C. PMID:22859019

  18. Computational insights on sulfonamide imprinted polymers.

    PubMed

    Isarankura-Na-Ayudhya, Chartchalerm; Nantasenamat, Chanin; Buraparuangsang, Prasit; Piacham, Theeraphon; Ye, Lei; Bülow, Leif; Prachayasittikul, Virapong

    2008-12-10

    Molecular imprinting is one of the most efficient methods for preparing synthetic receptors that possess user defined recognition properties. Despite general success of non-covalent imprinting for a large variety of templates, some groups of compounds remain difficult to tackle due to their structural complexity. In this study we investigate preparation of molecularly imprinted polymers that can bind sulfonamide compounds, which represent important drug candidates. Compared to the biological system that utilizes metal coordinated interaction, the imprinted polymer provided pronounced selectivity when hydrogen bond interaction was employed in an organic solvent. Computer simulation of the interaction between the sulfonamide template and functional monomers pointed out that although methacrylic acid had strong interaction energy with the template, it also possessed high non-specific interaction with the solvent molecules of tetrahydrofuran as well as being prone to self-complexation. On the other hand, 1-vinyl-imidazole was suitable for imprinting sulfonamides as it did not cross-react with the solvent molecules or engage in self-complexation structures.

  19. Selective Binding of Organophosphate Pesticides Using Molecular Imprinted Polymers

    DTIC Science & Technology

    2005-10-01

    MIPs . SELECTIVE BINDING OF ORGANOPHOSPHATE PESTICIDES USING MOLECULAR IMPRINTED POLYMERS . *Ali M. Saboori...Maryland 20910-7500. ABSTRACT Molecular Imprinted Polymers ( MIPs ) have been used for recognition and binding of different compounds. We are...INTRODUCTION Molecular Imprinted Polymers ( MIPs ) are highly cross-linked polymers , which are formed by cross- linking monomer in

  20. The interval between Ins2 and Ascl2 is dispensable for imprinting centre function in the murine Beckwith-Wiedemann region.

    PubMed

    Lefebvre, Louis; Mar, Lynn; Bogutz, Aaron; Oh-McGinnis, Rosemary; Mandegar, Mohammad A; Paderova, Jana; Gertsenstein, Marina; Squire, Jeremy A; Nagy, Andras

    2009-11-15

    Imprinted genes are commonly clustered in domains across the mammalian genome, suggesting a degree of coregulation via long-range coordination of their monoallelic transcription. The distal end of mouse chromosome 7 (Chr 7) contains two clusters of imprinted genes within a approximately 1 Mb domain. This region is conserved on human 11p15.5 where it is implicated in the Beckwith-Wiedemann syndrome. In both species, imprinted regulation requires two critical cis-acting imprinting centres, carrying different germline epigenetic marks and mediating imprinted expression in the proximal and distal sub-domains. The clusters are separated by a region containing the gene for tyrosine hydroxylase (Th) as well as a high density of short repeats and retrotransposons in the mouse. We have used the Cre-loxP recombination system in vivo to engineer an interstitial deletion of this approximately 280-kb intervening region previously proposed to participate in the imprinting mechanism or to act as a boundary between the two sub-domains. The deletion allele, Del(7AI), is silent with respect to epigenetic marking at the two flanking imprinting centres. Reciprocal inheritance of Del(7AI) demonstrates that the deleted region, which represents more than a quarter of the previously defined imprinted domain, is associated with intrauterine growth restriction in maternal heterozygotes. In homozygotes, the deficiency behaves as a Th null allele and can be rescued pharmacologically by bypassing the metabolic requirement for TH in utero. Our results show that the deleted interval is not required for normal imprinting on distal Chr 7 and uncover a new imprinted growth phenotype.

  1. Imprinting control regions (ICRs) are marked by mono-allelic bivalent chromatin when transcriptionally inactive.

    PubMed

    Maupetit-Méhouas, Stéphanie; Montibus, Bertille; Nury, David; Tayama, Chiharu; Wassef, Michel; Kota, Satya K; Fogli, Anne; Cerqueira Campos, Fabiana; Hata, Kenichiro; Feil, Robert; Margueron, Raphael; Nakabayashi, Kazuhiko; Court, Franck; Arnaud, Philippe

    2016-01-29

    Parental allele-specific expression of imprinted genes is mediated by imprinting control regions (ICRs) that are constitutively marked by DNA methylation imprints on the maternal or paternal allele. Mono-allelic DNA methylation is strictly required for the process of imprinting and has to be faithfully maintained during the entire life-span. While the regulation of DNA methylation itself is well understood, the mechanisms whereby the opposite allele remains unmethylated are unclear. Here, we show that in the mouse, at maternally methylated ICRs, the paternal allele, which is constitutively associated with H3K4me2/3, is marked by default by H3K27me3 when these ICRs are transcriptionally inactive, leading to the formation of a bivalent chromatin signature. Our data suggest that at ICRs, chromatin bivalency has a protective role by ensuring that DNA on the paternal allele remains unmethylated and protected against spurious and unscheduled gene expression. Moreover, they provide the proof of concept that, beside pluripotent cells, chromatin bivalency is the default state of transcriptionally inactive CpG island promoters, regardless of the developmental stage, thereby contributing to protect cell identity.

  2. Tet-mediated imprinting erasure in H19 locus following reprogramming of spermatogonial stem cells to induced pluripotent stem cells.

    PubMed

    Bermejo-Álvarez, P; Ramos-Ibeas, P; Park, K E; Powell, A P; Vansandt, L; Derek, Bickhart; Ramirez, M A; Gutiérrez-Adán, A; Telugu, B P

    2015-09-02

    Selective methylation of CpG islands at imprinting control regions (ICR) determines the monoparental expression of a subset of genes. Currently, it is unclear whether artificial reprogramming induced by the expression of Yamanaka factors disrupts these marks and whether cell type of origin affects the dynamics of reprogramming. In this study, spermatogonial stem cells (SSC) that harbor paternalized imprinting marks, and fibroblasts were reprogrammed to iPSC (SSCiPSC and fiPSC). The SSCiPSC were able to form teratomas and generated chimeras with a higher skin chimerism than those derived from fiPSC. RNA-seq revealed extensive reprogramming at the transcriptional level with 8124 genes differentially expressed between SSC and SSCiPSC and only 490 between SSCiPSC and fiPSC. Likewise, reprogramming of SSC affected 26 of 41 imprinting gene clusters known in the mouse genome. A closer look at H19 ICR revealed complete erasure in SSCiPSC in contrast to fiPSC. Imprinting erasure in SSCiPSC was maintained even after in vivo differentiation into teratomas. Reprogramming of SSC from Tet1 and Tet2 double knockout mice however lacked demethylation of H19 ICR. These results suggest that imprinting erasure during reprogramming depends on the epigenetic landscape of the precursor cell and is mediated by TETs at the H19 locus.

  3. Tet-mediated imprinting erasure in H19 locus following reprogramming of spermatogonial stem cells to induced pluripotent stem cells

    PubMed Central

    Bermejo-Álvarez, P.; Ramos-Ibeas, P.; Park, K.E.; Powell, A. P.; Vansandt, L.; Derek, Bickhart; Ramirez, M. A.; Gutiérrez-Adán, A.; Telugu, B. P.

    2015-01-01

    Selective methylation of CpG islands at imprinting control regions (ICR) determines the monoparental expression of a subset of genes. Currently, it is unclear whether artificial reprogramming induced by the expression of Yamanaka factors disrupts these marks and whether cell type of origin affects the dynamics of reprogramming. In this study, spermatogonial stem cells (SSC) that harbor paternalized imprinting marks, and fibroblasts were reprogrammed to iPSC (SSCiPSC and fiPSC). The SSCiPSC were able to form teratomas and generated chimeras with a higher skin chimerism than those derived from fiPSC. RNA-seq revealed extensive reprogramming at the transcriptional level with 8124 genes differentially expressed between SSC and SSCiPSC and only 490 between SSCiPSC and fiPSC. Likewise, reprogramming of SSC affected 26 of 41 imprinting gene clusters known in the mouse genome. A closer look at H19 ICR revealed complete erasure in SSCiPSC in contrast to fiPSC. Imprinting erasure in SSCiPSC was maintained even after in vivo differentiation into teratomas. Reprogramming of SSC from Tet1 and Tet2 double knockout mice however lacked demethylation of H19 ICR. These results suggest that imprinting erasure during reprogramming depends on the epigenetic landscape of the precursor cell and is mediated by TETs at the H19 locus. PMID:26328763

  4. Molecular imprinted polymers as drug delivery vehicles.

    PubMed

    Zaidi, Shabi Abbas

    2016-09-01

    This review is aimed to discuss the molecular imprinted polymer (MIP)-based drug delivery systems (DDS). Molecular imprinted polymers have proved to possess the potential and also as a suitable material in several areas over a long period of time. However, only recently it has been employed for pharmaceuticals and biomedical applications, particularly as drug delivery vehicles due to properties including selective recognition generated from imprinting the desired analyte, favorable in harsh experimental conditions, and feedback-controlled recognitive drug release. Hence, this review will discuss their synthesis, the reason they are selected as drug delivery vehicles and for their applications in several drug administration routes (i.e. transdermal, ocular and gastrointestinal or stimuli-reactive routes).

  5. Monoallelic Loss of the Imprinted Gene Grb10 Promotes Tumor Formation in Irradiated Nf1+/- Mice

    PubMed Central

    Mroue, Rana; Huang, Brian; Braunstein, Steve; Firestone, Ari J.; Nakamura, Jean L.

    2015-01-01

    Imprinted genes are expressed from only one parental allele and heterozygous loss involving the expressed allele is sufficient to produce complete loss of protein expression. Genetic alterations are common in tumorigenesis but the role of imprinted genes in this process is not well understood. In earlier work we mutagenized mice heterozygous for the Neurofibromatosis I tumor suppressor gene (NF1) to model radiotherapy-associated second malignant neoplasms that arise in irradiated NF1 patients. Expression analysis of tumor cell lines established from our mouse models identified Grb10 expression as widely absent. Grb10 is an imprinted gene and polymorphism analysis of cell lines and primary tumors demonstrates that the expressed allele is commonly lost in diverse Nf1 mutant tumors arising in our mouse models. We performed functional studies to test whether Grb10 restoration or loss alter fundamental features of the tumor growth. Restoring Grb10 in Nf1 mutant tumors decreases proliferation, decreases soft agar colony formation and downregulates Ras signaling. Conversely, Grb10 silencing in untransformed mouse embryo fibroblasts significantly increased cell proliferation and increased Ras-GTP levels. Expression of a constitutively activated MEK rescued tumor cells from Grb10-mediated reduction in colony formation. These studies reveal that Grb10 loss can occur during in vivo tumorigenesis, with a functional consequence in untransformed primary cells. In tumors, Grb10 loss independently promotes Ras pathway hyperactivation, which promotes hyperproliferation, an early feature of tumor development. In the context of a robust Nf1 mutant mouse model of cancer this work identifies a novel role for an imprinted gene in tumorigenesis. PMID:26000738

  6. Molecularly imprinted polymers for bioanalytical sample preparation.

    PubMed

    Gama, Mariana Roberto; Bottoli, Carla Beatriz Grespan

    2017-02-01

    Molecularly imprinted polymers (MIP) are stable polymers with molecular recognition abilities, provided by the presence of a template during their synthesis, and are excellent materials with high selectivity for sample preparation in bioanalytical methods. This short review discusses aspects of MIP preparation and its applications as a sorbent material in pharmaceutical and biomedical analysis. MIP in different extraction configurations, including classical solid-phase extraction, solid-phase microextraction, magnetic molecularly imprinted solid-phase extraction, microextraction by packed sorbent and solid-phase extraction in pipette tips, are used to illustrate the good performance of this type of sorbent for sample preparation procedures of complex matrices, especially prior to bioanalytical approaches.

  7. [Imprint cytology in the diagnosis of tumors of the thyroid].

    PubMed

    Pluot, M; Faroux, M J; Rain, J; Patey, M; Mallaisy, T; Simatos, A

    1989-01-01

    We have correlated imprint cytology findings in thyroid tumors to the results of preoperative fine needle aspiration and operative specimen histology. Specificity of imprint cytology proved greater than that of fine needle aspiration cytology and topographic correlations were particularly helpful. Imprint cytology can improve the intraoperative histologic diagnosis. Because abundant cells are available, imprint thyroid cytology is ideal for teaching and training cytologists. Imprint cytology provides enough cells to perform special techniques, such as quantitative cytology, that are useful for the diagnosis of some tumor varieties (e.g. follicular tumors).

  8. Construction and evolution of imprinted loci in mammals.

    PubMed

    Hore, Timothy A; Rapkins, Robert W; Graves, Jennifer A Marshall

    2007-09-01

    Genomic imprinting first evolved in mammals around the time that humans last shared a common ancestor with marsupials and monotremes (180-210 million years ago). Recent comparisons of large imprinted domains in these divergent mammalian groups have shown that imprinting evolved haphazardly at various times in different lineages, perhaps driven by different selective forces. Surprisingly, some imprinted domains were formed relatively recently, using non-imprinted components acquired from unexpected genomic regions. Rearrangement and the insertion of retrogenes, small nucleolar RNAs, microRNAs, differential CpG methylation and control by non-coding RNA often accompanied the acquisition of imprinting. Here, we use comparisons between different mammalian groups to chart the course of evolution of two related epigenetic regulatory systems in mammals: genomic imprinting and X-chromosome inactivation.

  9. Enhanced removal of bilirubin on molecularly imprinted titania film.

    PubMed

    Yang, Zheng-peng; Yan, Jin-long; Zhang, Chun-jing; Luo, Shu-qiong

    2011-10-01

    Titania film imprinted by bilirubin molecule at the surface of quartz crystal was prepared using molecular imprinting and surface sol-gel process. The molecularly imprinted titania film was characterized by FTIR spectra, and the interaction between bilirubin and imprinted film was investigated using quartz crystal microbalance (QCM) technique. Compared with pure titania film, the molecularly imprinted titania film exhibits a much higher adsorption capacity for the target molecule, and the adsorption kinetic parameter estimated from the in situ frequency measurement is about 1.6×10(8) M(-1), which is ten times higher than that obtained on pure titania film. The photocatalytic measurements indicate that the bilirubin adsorbed on molecularly imprinted titania film can be completely removed under UV illumination. Moreover, our study indicates that the molecularly imprinted titania film possesses a better stability and reusability.

  10. Thermochemical study of amino acid imprinted polymer films.

    PubMed

    Chai, Ziyi; BelBruno, Joseph J

    2015-11-01

    Molecularly imprinted polymers provide an alternative to traditional methods of amino acid analysis. The imprinted polymers are more robust and significantly less expensive than, for example, ELISA analysis. Amino acid imprinted nylon-6 thin films were studied by differential scanning calorimetry and scanning electron microscopy. Endothermic peaks were observed for imprinted films at temperatures higher than that for pure nylon, indicating the formation of a more-ordered, hydrogen bonded polymer. Removal of the amino acid from the imprinted film resulted in reversion to the peak observed for pure nylon-6. Additives, β-cyclodextrin and multiwalled carbon nanotubes, were added to the imprinted polymer solutions as a means to increase the porosity of the films. These studies resulted in alternative morphologies and calorimetric results that provide additional functionalities and applications for imprinted polymers.

  11. Molecular recognition effects in atomistic models of imprinted polymers.

    PubMed

    Dourado, Eduardo M A; Herdes, Carmelo; van Tassel, Paul R; Sarkisov, Lev

    2011-01-01

    In this article we present a model for molecularly imprinted polymers, which considers both complexation processes in the pre-polymerization mixture and adsorption in the imprinted structures within a single consistent framework. As a case study we investigate MAA/EGDMA polymers imprinted with pyrazine and pyrimidine. A polymer imprinted with pyrazine shows substantial selectivity towards pyrazine over pyrimidine, thus exhibiting molecular recognition, whereas the pyrimidine imprinted structure shows no preferential adsorption of the template. Binding sites responsible for the molecular recognition of pyrazine involve one MAA molecule and one EGDMA molecule, forming associations with the two functional groups of the pyrazine molecule. Presence of these specific sites in the pyrazine imprinted system and lack of the analogous sites in the pyrimidine imprinted system is directly linked to the complexation processes in the pre-polymerization solution. These processes are quite different for pyrazine and pyrimidine as a result of both enthalpic and entropic effects.

  12. Induced pluripotent stem cells can be used to model the genomic imprinting disorder Prader-Willi syndrome.

    PubMed

    Yang, Jiayin; Cai, Jie; Zhang, Ya; Wang, Xianming; Li, Wen; Xu, Jianyong; Li, Feng; Guo, Xiangpeng; Deng, Kang; Zhong, Mei; Chen, Yonglong; Lai, Liangxue; Pei, Duanqing; Esteban, Miguel A

    2010-12-17

    The recent discovery of induced pluripotent stem cell (iPSC) technology provides an invaluable tool for creating in vitro representations of human genetic conditions. This is particularly relevant for those diseases that lack adequate animal models or where the species comparison is difficult, e.g. imprinting diseases such as the neurogenetic disorder Prader-Willi syndrome (PWS). However, recent reports have unveiled transcriptional and functional differences between iPSCs and embryonic stem cells that in cases are attributable to imprinting errors. This has suggested that human iPSCs may not be useful to model genetic imprinting diseases. Here, we describe the generation of iPSCs from a patient with PWS bearing a partial translocation of the paternally expressed chromosome 15q11-q13 region to chromosome 4. The resulting iPSCs match all standard criteria of bona fide reprogramming and could be readily differentiated into tissues derived from the three germ layers, including neurons. Moreover, these iPSCs retain a high level of DNA methylation in the imprinting center of the maternal allele and show concomitant reduced expression of the disease-associated small nucleolar RNA HBII-85/SNORD116. These results indicate that iPSCs may be a useful tool to study PWS and perhaps other genetic imprinting diseases as well.

  13. Stochastic Loss of Silencing of the Imprinted Ndn/NDN Allele, in a Mouse Model and Humans with Prader-Willi Syndrome, Has Functional Consequences

    PubMed Central

    Unmehopa, Unga; Matarazzo, Valery; Watrin, Françoise; Linke, Matthias; Georges, Beatrice; Bischof, Jocelyn; Dijkstra, Femke; Bloemsma, Monique; Corby, Severine; Michel, François J.; Wevrick, Rachel; Zechner, Ulrich; Swaab, Dick; Dudley, Keith; Bezin, Laurent; Muscatelli, Françoise

    2013-01-01

    Genomic imprinting is a process that causes genes to be expressed from one allele only according to parental origin, the other allele being silent. Diseases can arise when the normally active alleles are not expressed. In this context, low level of expression of the normally silent alleles has been considered as genetic noise although such expression has never been further studied. Prader-Willi Syndrome (PWS) is a neurodevelopmental disease involving imprinted genes, including NDN, which are only expressed from the paternally inherited allele, with the maternally inherited allele silent. We present the first in-depth study of the low expression of a normally silent imprinted allele, in pathological context. Using a variety of qualitative and quantitative approaches and comparing wild-type, heterozygous and homozygous mice deleted for Ndn, we show that, in absence of the paternal Ndn allele, the maternal Ndn allele is expressed at an extremely low level with a high degree of non-genetic heterogeneity. The level of this expression is sex-dependent and shows transgenerational epigenetic inheritance. In about 50% of mutant mice, this expression reduces birth lethality and severity of the breathing deficiency, correlated with a reduction in the loss of serotonergic neurons. In wild-type brains, the maternal Ndn allele is never expressed. However, using several mouse models, we reveal a competition between non-imprinted Ndn promoters which results in monoallelic (paternal or maternal) Ndn expression, suggesting that Ndn allelic exclusion occurs in the absence of imprinting regulation. Importantly, specific expression of the maternal NDN allele is also detected in post-mortem brain samples of PWS individuals. Our data reveal an unexpected epigenetic flexibility of PWS imprinted genes that could be exploited to reactivate the functional but dormant maternal alleles in PWS. Overall our results reveal high non-genetic heterogeneity between genetically identical individuals

  14. Genomic imprinting: an obsession with depilatory mice.

    PubMed

    Haig, David; Úbeda, Francisco

    2011-04-12

    Excessive grooming in mice has been promoted as a model of human obsessive-compulsive disorders. A recent paper adds Grb10 to the list of genes with effects on behavioral hair loss, with the added twist that this time the gene is imprinted.

  15. Imprinting Technology in Electrochemical Biomimetic Sensors.

    PubMed

    Frasco, Manuela F; Truta, Liliana A A N A; Sales, M Goreti F; Moreira, Felismina T C

    2017-03-06

    Biosensors are a promising tool offering the possibility of low cost and fast analytical screening in point-of-care diagnostics and for on-site detection in the field. Most biosensors in routine use ensure their selectivity/specificity by including natural receptors as biorecognition element. These materials are however too expensive and hard to obtain for every biochemical molecule of interest in environmental and clinical practice. Molecularly imprinted polymers have emerged through time as an alternative to natural antibodies in biosensors. In theory, these materials are stable and robust, presenting much higher capacity to resist to harsher conditions of pH, temperature, pressure or organic solvents. In addition, these synthetic materials are much cheaper than their natural counterparts while offering equivalent affinity and sensitivity in the molecular recognition of the target analyte. Imprinting technology and biosensors have met quite recently, relying mostly on electrochemical detection and enabling a direct reading of different analytes, while promoting significant advances in various fields of use. Thus, this review encompasses such developments and describes a general overview for building promising biomimetic materials as biorecognition elements in electrochemical sensors. It includes different molecular imprinting strategies such as the choice of polymer material, imprinting methodology and assembly on the transduction platform. Their interface with the most recent nanostructured supports acting as standard conductive materials within electrochemical biomimetic sensors is pointed out.

  16. Imprinting Technology in Electrochemical Biomimetic Sensors

    PubMed Central

    Frasco, Manuela F.; Truta, Liliana A. A. N. A.; Sales, M. Goreti F.; Moreira, Felismina T. C.

    2017-01-01

    Biosensors are a promising tool offering the possibility of low cost and fast analytical screening in point-of-care diagnostics and for on-site detection in the field. Most biosensors in routine use ensure their selectivity/specificity by including natural receptors as biorecognition element. These materials are however too expensive and hard to obtain for every biochemical molecule of interest in environmental and clinical practice. Molecularly imprinted polymers have emerged through time as an alternative to natural antibodies in biosensors. In theory, these materials are stable and robust, presenting much higher capacity to resist to harsher conditions of pH, temperature, pressure or organic solvents. In addition, these synthetic materials are much cheaper than their natural counterparts while offering equivalent affinity and sensitivity in the molecular recognition of the target analyte. Imprinting technology and biosensors have met quite recently, relying mostly on electrochemical detection and enabling a direct reading of different analytes, while promoting significant advances in various fields of use. Thus, this review encompasses such developments and describes a general overview for building promising biomimetic materials as biorecognition elements in electrochemical sensors. It includes different molecular imprinting strategies such as the choice of polymer material, imprinting methodology and assembly on the transduction platform. Their interface with the most recent nanostructured supports acting as standard conductive materials within electrochemical biomimetic sensors is pointed out. PMID:28272314

  17. Molecular Imprinting Applications in Forensic Science.

    PubMed

    Yılmaz, Erkut; Garipcan, Bora; Patra, Hirak K; Uzun, Lokman

    2017-03-28

    Producing molecular imprinting-based materials has received increasing attention due to recognition selectivity, stability, cast effectiveness, and ease of production in various forms for a wide range of applications. The molecular imprinting technique has a variety of applications in the areas of the food industry, environmental monitoring, and medicine for diverse purposes like sample pretreatment, sensing, and separation/purification. A versatile usage, stability and recognition capabilities also make them perfect candidates for use in forensic sciences. Forensic science is a demanding area and there is a growing interest in molecularly imprinted polymers (MIPs) in this field. In this review, recent molecular imprinting applications in the related areas of forensic sciences are discussed while considering the literature of last two decades. Not only direct forensic applications but also studies of possible forensic value were taken into account like illicit drugs, banned sport drugs, effective toxins and chemical warfare agents in a review of over 100 articles. The literature was classified according to targets, material shapes, production strategies, detection method, and instrumentation. We aimed to summarize the current applications of MIPs in forensic science and put forth a projection of their potential uses as promising alternatives for benchmark competitors.

  18. Membrane separations using molecularly imprinted polymers.

    PubMed

    Ulbricht, Mathias

    2004-05-05

    This review presents an overview on the promising field of molecularly imprinted membranes (MIM). The focus is onto the separation of molecules in liquid mixtures via membrane transport selectivity. First, the status of synthetic membranes and membrane separation technology is briefly summarized, emphasizing the need for novel membranes with higher selectivities. Innovative principles for the preparation of membranes with improved or novel functionality include self-assembly or supramolecular aggregation as well as the use of templates. Based on a detailed analysis of the literature, the main established preparation methods for MIM are outlined: simultaneous membrane formation and imprinting, or preparation of imprinted composite membranes. Then, the separation capability of MIM is discussed for two different types, as a function of their barrier structure. Microporous MIM can continuously separate mixtures based on facilitated diffusion of the template, or they can change their permeability in the presence of the template ("gate effect"). Macroporous MIM can be developed towards molecule-specific membrane adsorbers. Emerging further combinations of molecularly imprinted polymers (MIPs), especially MIP nanoparticles or microgels, with membranes and membrane processes are briefly outlined as well. Finally, the application potential for advanced MIM separation technologies is summarized.

  19. Plastic Antibodies: Molecular Recognition with Imprinted Polymers

    ERIC Educational Resources Information Center

    Rushton, Gregory T.; Furmanski, Brian; Shimizu, Ken D.

    2005-01-01

    Synthetic polymers are prepared and tested in a study for their molecular recognition properties of an adenine derivative, ethyl adenine-9-acetate (EA9A), within two laboratory periods. The procedure introduces undergraduate chemistry students to noncovalent molecular imprinting as well as the analytical techniques for assessing their recognition…

  20. Molecularly imprinted polymers for biomolecular recognition.

    PubMed

    Molinelli, Alexandra; Janotta, Markus; Mizaikoff, Boris

    2005-01-01

    Molecular imprinting of polymers is a concept for the synthetic formation of structurally organized materials providing binding sites with molecular selectivity. Compared to biological receptors, these polymeric recognition systems have the advantage of superior chemical and mechanical stability with potential applications in areas such as biomimetic catalysis and engineering, biomedical analysis, sensor technology, or the food industry. In particular, molecularly imprinted polymers (MIPs) providing selectivity for biorelated molecules are gaining substantial importance. In this context, a self-assembly approach for the synthesis of imprinted polymers against the flavonol quercetin is presented, which is exemplary for the biologically relevant group of flavonoid compounds. The creation of synthetic selective recognition sites for this biomolecule is demonstrated by comparing the separation capabilities of imprinted and nonimprinted polymer particles for several structurally related molecules via high-performance liquid chromatography experiments. The developed quercetin-MIP enables selective extraction of quercetin even from complex mixtures, demonstrating the potential for designing biomimetic recognition materials with improved selectivity for biomolecules with tunable functionality at a nanoscale.

  1. Molecularly imprinted polymers for some reactive dyes.

    PubMed

    Okutucu, Burcu; Akkaya, Alper; Pazarlioglu, Nurdan Kasikara

    2010-01-01

    Depending upon their structure, azo- and anthraquinonic dyes are the two major classes and together represent 90% of all organic colorants. Adsorption of dye molecules onto a sorbent can be an effective, low-cost method of color removal. Most of the techniques used for removal of dyes are of high production cost, and the regeneration also makes them uneconomical. There is much interest in the development of cheaper and effective newer materials for use as adsorbents. Molecular imprinting is a new kind of materials that can be alternative adsorbents. In this study, molecularly imprinted polymers of three textile dyes (Cibacron Orange P-4R, Cibacron Red P-4B, Cibacron Black PSG) were prepared. Methacrylic acid was used as a monomer for red and orange dyes and acrylamide was used for black dye. Methanol:acetonitrile was used as a porogen. The selective recognition ability of the molecularly imprinted polymers was studied by an equilibrium-adsorption batch method. The adsorption data are for Cibacron Black PSG 65% and nonimprinted polymer (NIP) 25%; Cibacron Red P-4B 72% and NIP 18%; and Cibacron Orange P-4R 45% and NIP 10%, respectively. Dye-imprinted polymers were used as a solid-phase extraction material for selective adsorption from wastewater of textile factory.

  2. Imprinting in human disease with special reference to transient neonatal diabetes and Beckwith-Wiedemann syndrome.

    PubMed

    Temple, I Karen

    2007-01-01

    There are at least 6 well-studied imprinting domains on human autosomes. Each domain is under the regulatory control of an 'imprinting centre' that harbours a differentially methylated region. A number of molecular mechanisms result in differential silencing of some genes within these domains and gene expression is tightly regulated in normal individuals. However, this makes them vulnerable to naturally occurring genetic and epigenetic aberrations. Nine recognisable developmental syndromes have been described due to abnormalities within these 6 domains: transient neonatal diabetes (TND; at 6q24); Beckwith- Wiedemann syndrome (BWS) and Silver-Russell syndrome (at 11p15.5; 2 imprinted domains); maternal and paternal uniparental disomy syndromes (at 14q32); Angelman and Prader-Willi syndromes (at 15q11-13), and pseudohypoparathyroidism type 1b (at 20q12-13). Furthermore, it is now recognised that involvement at multiple domains can occur simultaneously and result in what has been described as the hypomethylation syndrome. TND and BWS are discussed in more detail as examples of imprinting disorders.

  3. A Path to Soluble Molecularly Imprinted Polymers

    PubMed Central

    Verma, Abhilasha; Murray, George M.

    2011-01-01

    Molecular imprinting is a technique for making a selective binding site for a specific chemical. The technique involves building a polymeric scaffold of molecular complements containing the target molecule. Subsequent removal of the target leaves a cavity with a structural “memory” of the target. Molecularly imprinted polymers (MIPs) can be employed as selective adsorbents of specific molecules or molecular functional groups. In addition, sensors for specific molecules can be made using optical transduction through lumiphores residing in the imprinted site. We have found that the use of metal ions as chromophores can improve selectivity due to selective complex formation. The combination of molecular imprinting and spectroscopic selectivity can result in sensors that are highly sensitive and nearly immune to interferences. A weakness of conventional MIPs with regard to processing is the insolubility of crosslinked polymers. Traditional MIPs are prepared either as monoliths and ground into powders or are prepared in situ on a support. This limits the applicability of MIPs by imposing tedious or difficult processes for their inclusion in devices. The size of the particles hinders diffusion and slows response. These weaknesses could be avoided if a means were found to prepare individual macromolecules with crosslinked binding sites with soluble linear polymeric arms. This process has been made possible by controlled free radical polymerization techniques that can form pseudo-living polymers. Modern techniques of controlled free radical polymerization allow the preparation of block copolymers with potentially crosslinkable substituents in specific locations. The inclusion of crosslinkable mers proximate to the binding complex in the core of a star polymer allows the formation of molecularly imprinted macromolecules that are soluble and processable. Due to the much shorter distance for diffusion, the polymers exhibit rapid responses. This paper reviews the methods

  4. Type 2 Diabetes Susceptibility in the Greek-Cypriot Population: Replication of Associations with TCF7L2, FTO, HHEX, SLC30A8 and IGF2BP2 Polymorphisms

    PubMed Central

    Votsi, Christina; Toufexis, Costas; Michailidou, Kyriaki; Antoniades, Athos; Skordis, Nicos; Karaolis, Minas; Pattichis, Constantinos S.; Christodoulou, Kyproula

    2017-01-01

    Type 2 diabetes (T2D) has been the subject of numerous genetic studies in recent years which revealed associations of the disease with a large number of susceptibility loci. We hereby initiate the evaluation of T2D susceptibility loci in the Greek-Cypriot population by performing a replication case-control study. One thousand and eighteen individuals (528 T2D patients, 490 controls) were genotyped at 21 T2D susceptibility loci, using the allelic discrimination method. Statistically significant associations of T2D with five of the tested single nucleotide polymorphisms (SNPs) (TCF7L2 rs7901695, FTO rs8050136, HHEX rs5015480, SLC30A8 rs13266634 and IGF2BP2 rs4402960) were observed in this study population. Furthermore, 14 of the tested SNPs had odds ratios (ORs) in the same direction as the previously published studies, suggesting that these variants can potentially be used in the Greek-Cypriot population for predictive testing of T2D. In conclusion, our findings expand the genetic assessment of T2D susceptibility loci and reconfirm five of the worldwide established loci in a distinct, relatively small, newly investigated population. PMID:28067832

  5. Parametric and nonparametric multipoint linkage analysis with imprinting and two-locus-trait models: application to mite sensitization.

    PubMed Central

    Strauch, K; Fimmers, R; Kurz, T; Deichmann, K A; Wienker, T F; Baur, M P

    2000-01-01

    We present two extensions to linkage analysis for genetically complex traits. The first extension allows investigators to perform parametric (LOD-score) analysis of traits caused by imprinted genes-that is, of traits showing a parent-of-origin effect. By specification of two heterozygote penetrance parameters, paternal and maternal origin of the mutation can be treated differently in terms of probability of expression of the trait. Therefore, a single-disease-locus-imprinting model includes four penetrances instead of only three. In the second extension, parametric and nonparametric linkage analysis with two trait loci is formulated for a multimarker setting, optionally taking imprinting into account. We have implemented both methods into the program GENEHUNTER. The new tools, GENEHUNTER-IMPRINTING and GENEHUNTER-TWOLOCUS, were applied to human family data for sensitization to mite allergens. The data set comprises pedigrees from England, Germany, Italy, and Portugal. With single-disease-locus-imprinting MOD-score analysis, we find several regions that show at least suggestive evidence for linkage. Most prominently, a maximum LOD score of 4.76 is obtained near D8S511, for the English population, when a model that implies complete maternal imprinting is used. Parametric two-trait-locus analysis yields a maximum LOD score of 6.09 for the German population, occurring exactly at D4S430 and D18S452. The heterogeneity model specified for analysis alludes to complete maternal imprinting at both disease loci. Altogether, our results suggest that the two novel formulations of linkage analysis provide valuable tools for genetic mapping of multifactorial traits. PMID:10796874

  6. NMDA receptor antagonists extend the sensitive period for imprinting.

    PubMed

    Parsons, C H; Rogers, L J

    2000-03-01

    Filial imprinting in the domestic chick occurs during a sensitive period of development. The exact timing of this period can vary according to the methods used to measure imprinting. Using our imprinting paradigm, we have shown that normal, dark-reared chicks lose the ability to imprint after the second day post-hatching. Further, we reported that chicks treated 10 h after hatching with a mixture of the noncompetitive NMDA receptor antagonist ketamine (55 mg/kg) and the alpha(2)-adrenergic receptor agonist xylazine (6 mg/kg) were able to imprint on day 8 after hatching, whereas controls treated with saline did not imprint. We now show that the effect of the ketamine-xylazine mixture can be mimicked by treating chicks with ketamine alone or with another noncompetitive NMDA receptor antagonist, MK-801 (5 mg/kg). Treating chicks with a single dose of ketamine (55 mg/kg) or with a single dose of xylazine (6 mg/kg) failed to produce the effect on the sensitive period. However, prolonging the action of ketamine by treating chicks with two doses of ketamine (at 10 and 12 h after hatching) did allow imprinting on day 8. In contrast, prolonging the action of xylazine had no effect on the sensitive period for imprinting. Chicks treated with MK-801 were also able to imprint on day 8. Thus, we have evidence that the NMDA receptor system is involved in the mechanisms that control the sensitive period for imprinting.

  7. Quantifying genomic imprinting in the presence of linkage.

    PubMed

    Vincent, Quentin; Alcaïs, Alexandre; Alter, Andrea; Schurr, Erwin; Abel, Laurent

    2006-12-01

    Genomic imprinting decreases the power of classical linkage analysis, in which paternal and maternal transmissions of marker alleles are equally weighted. Several methods have been proposed for taking genomic imprinting into account in the model-free linkage analysis of binary traits. However, none of these methods are suitable for the formal identification and quantification of genomic imprinting in the presence of linkage. In addition, the available methods are designed for use with pure sib-pairs, requiring artificial decomposition in cases of larger sibships, leading to a loss of power. We propose here the maximum likelihood binomial method adaptive for imprinting (MLB-I), which is a unified analytic framework giving rise to specific tests in sibships of any size for (i) linkage adaptive to imprinting, (ii) genomic imprinting in the presence of linkage, and (iii) partial versus complete genomic imprinting. In addition, we propose an original measure for quantifying genomic imprinting. We have derived and validated the distribution of the three tests under their respective null hypotheses for various genetic models, and have assessed the power of these tests in simulations. This method can readily be applied to genome-wide scanning, as illustrated here for leprosy sibships. Our approach provides a novel tool for dissecting genomic imprinting in model-free linkage analysis, and will be of considerable value for identifying and evaluating the contribution of imprinted genes to complex diseases.

  8. Immunoendocrinology: faulty hormonal imprinting in the immune system.

    PubMed

    Csaba, György

    2014-06-01

    Hormonal imprinting is an epigenetic process which is taking place perinatally at the first encounter between the developing hormone receptors and their target hormones. The hormonal imprinting influences the binding capacity of receptors, the hormone synthesis of the cells, and other hormonally regulated functions, as sexual behavior, aggressivity, empathy, etc. However, during the critical period, when the window for imprinting is open, molecules similar to the physiological imprinters as synthetic hormone analogs, other members of the hormone families, environmental pollutants, etc. can cause faulty imprinting with life-long consequences. The developing immune system, the cells of which also have receptors for hormones, is very sensitive to faulty imprinting, which causes alterations in the antibody and cytokine production, in the ratio of immune cells, in the defense against bacterial and viral infections as well as against malignant tumors. Immune cells (lymphocytes, monocytes, granulocytes and mast cells) are also producing hormones which are secreted into the blood circulation as well as are transported locally (packed transport). This process is also disturbed by faulty imprinting. As immune cells are differentiating during the whole life, faulty imprinting could develop any time, however, the most decisive is the perinatal imprinting. The faulty imprinting is inherited to the progenies in general and especially in the case of immune system. In our modern world the number and amount of artificial imprinters (e.g. endocrine disruptors and drugs) are enormously increasing. The effects of the faulty imprinters most dangerous to the immune system are shown in the paper. The present and future consequences of the flood of faulty imprintings are unpredictable however, it is discussed.

  9. Characterization of three novel imprinted snoRNAs from mouse Irm gene.

    PubMed

    Xiao, Yu; Zhou, Hui; Qu, Liang-Hu

    2006-02-24

    Most, if not all, of snoRNAs in mammals are intron-encoded, implying the expressional and functional relativeness between the snoRNA and their hosts. By computational analysis of an intron database extracted from 65 known mouse imprinted genes, three novel orphan box C/D snoRNAs were identified from Irm gene which is maternally expressed and related to human disorders. The snoRNAs were positively detected and found to express in all the mouse tissues except kidney. The imprinted snoRNAs exhibit stringent structures, but quite variable in locations at their host introns, suggesting their maturation probably through a splicing independent manner. We characterized Irm as a new kind of snoRNA host gene which has no protein-coding capacity and no 5'TOP structure in its mRNA. The newly identified snoRNAs appear mouse-specific, however, their function remains to be elucidated.

  10. NOEY2 (ARHI), an imprinted putative tumor suppressor gene in ovarian and breast carcinomas

    PubMed Central

    Yu, Yinhua; Xu, Fengji; Peng, Hongqi; Fang, Xianjun; Zhao, Shulei; Li, Yang; Cuevas, Bruce; Kuo, Wen-Lin; Gray, Joe W.; Siciliano, Michael; Mills, Gordon B.; Bast, Robert C.

    1999-01-01

    Using differential display PCR, we have identified a gene [NOEY2, ARHI (designation by the Human Gene Nomenclature Committee)] with high homology to ras and rap that is expressed consistently in normal ovarian and breast epithelial cells but not in ovarian and breast cancers. Reexpression of NOEY2 through transfection suppresses clonogenic growth of breast and ovarian cancer cells. Growth suppression was associated with down-regulation of the cyclin D1 promoter activity and induction of p21WAF1/CIP1. In an effort to identify mechanisms leading to NOEY2 silencing in cancer, we found that the gene is expressed monoallelically and is imprinted maternally. Loss of heterozygosity of the gene was detected in 41% of ovarian and breast cancers. In most of cancer samples with loss of heterozygosity, the nonimprinted functional allele was deleted. Thus, NOEY2 appears to be a putative imprinted tumor suppressor gene whose function is abrogated in ovarian and breast cancers. PMID:9874798

  11. A small family of sushi-class retrotransposon-derived genes in mammals and their relation to genomic imprinting.

    PubMed

    Youngson, Neil A; Kocialkowski, Sylvia; Peel, Nina; Ferguson-Smith, Anne C

    2005-10-01

    Ty3/gypsy retrotransposons are rare in mammalian genomes despite their abundance in invertebrate and other vertebrate classes. Here we identify a family of nine conserved mammalian genes with homology to Ty3/gypsy retrotransposons but which have lost their ability to autonomously retrotranspose. Of these, five map to the X chromosome while the remaining four are autosomal. Comparative phylogenetic analyses show them to have strongest homology to the sushi-ichi element from Fugu rubripes. Two of the autosomal gene members, Peg10 and Rtl1, are known to be imprinted, being expressed from the paternally inherited chromosome homologue. This suggests, consistent with the host-parasite response theory of the evolution of the imprinting mechanism, that parental-origin specific epigenetic control may be mediated by genomic "parasitic" elements such as these. Alternatively, these elements may preferentially integrate into regions that are differentially modified on the two homologous chromosomes such as imprinted domains and the X chromosome and acquire monoallelic expression. We assess the imprinting status of the remaining autosomal members of this family and show them to be biallelically expressed in embryo and placenta. Furthermore, the methylation status of Rtl1 was assayed throughout development and was found to resemble that of actively, silenced repetitive elements rather than imprinted sequences. This indicates that the ability to undergo genomic imprinting is not an inherent property of all members of this family of retroelements. Nonetheless, the conservation but functional divergence between the different members suggests that they have undergone positive selection and acquired distinct endogenous functions within their mammalian hosts.

  12. Identification of the Imprinted KLF14 Transcription Factor Undergoing Human-Specific Accelerated Evolution

    PubMed Central

    Parker-Katiraee, Layla; Carson, Andrew R; Yamada, Takahiro; Arnaud, Philippe; Feil, Robert; Abu-Amero, Sayeda N; Moore, Gudrun E; Kaneda, Masahiro; Perry, George H; Stone, Anne C; Lee, Charles; Meguro-Horike, Makiko; Sasaki, Hiroyuki; Kobayashi, Keiko; Nakabayashi, Kazuhiko; Scherer, Stephen W

    2007-01-01

    Imprinted genes are expressed in a parent-of-origin manner and are located in clusters throughout the genome. Aberrations in the expression of imprinted genes on human Chromosome 7 have been suggested to play a role in the etiologies of Russell-Silver Syndrome and autism. We describe the imprinting of KLF14, an intronless member of the Krüppel-like family of transcription factors located at Chromosome 7q32. We show that it has monoallelic maternal expression in all embryonic and extra-embryonic tissues studied, in both human and mouse. We examine epigenetic modifications in the KLF14 CpG island in both species and find this region to be hypomethylated. In addition, we perform chromatin immunoprecipitation and find that the murine Klf14 CpG island lacks allele-specific histone modifications. Despite the absence of these defining features, our analysis of Klf14 in offspring from DNA methyltransferase 3a conditional knockout mice reveals that the gene's expression is dependent upon a maternally methylated region. Due to the intronless nature of Klf14 and its homology to Klf16, we suggest that the gene is an ancient retrotransposed copy of Klf16. By sequence analysis of numerous species, we place the timing of this event after the divergence of Marsupialia, yet prior to the divergence of the Xenarthra superclade. We identify a large number of sequence variants in KLF14 and, using several measures of diversity, we determine that there is greater variability in the human lineage with a significantly increased number of nonsynonymous changes, suggesting human-specific accelerated evolution. Thus, KLF14 may be the first example of an imprinted transcript undergoing accelerated evolution in the human lineage. PMID:17480121

  13. Identification of the imprinted KLF14 transcription factor undergoing human-specific accelerated evolution.

    PubMed

    Parker-Katiraee, Layla; Carson, Andrew R; Yamada, Takahiro; Arnaud, Philippe; Feil, Robert; Abu-Amero, Sayeda N; Moore, Gudrun E; Kaneda, Masahiro; Perry, George H; Stone, Anne C; Lee, Charles; Meguro-Horike, Makiko; Sasaki, Hiroyuki; Kobayashi, Keiko; Nakabayashi, Kazuhiko; Scherer, Stephen W

    2007-05-04

    Imprinted genes are expressed in a parent-of-origin manner and are located in clusters throughout the genome. Aberrations in the expression of imprinted genes on human Chromosome 7 have been suggested to play a role in the etiologies of Russell-Silver Syndrome and autism. We describe the imprinting of KLF14, an intronless member of the Krüppel-like family of transcription factors located at Chromosome 7q32. We show that it has monoallelic maternal expression in all embryonic and extra-embryonic tissues studied, in both human and mouse. We examine epigenetic modifications in the KLF14 CpG island in both species and find this region to be hypomethylated. In addition, we perform chromatin immunoprecipitation and find that the murine Klf14 CpG island lacks allele-specific histone modifications. Despite the absence of these defining features, our analysis of Klf14 in offspring from DNA methyltransferase 3a conditional knockout mice reveals that the gene's expression is dependent upon a maternally methylated region. Due to the intronless nature of Klf14 and its homology to Klf16, we suggest that the gene is an ancient retrotransposed copy of Klf16. By sequence analysis of numerous species, we place the timing of this event after the divergence of Marsupialia, yet prior to the divergence of the Xenarthra superclade. We identify a large number of sequence variants in KLF14 and, using several measures of diversity, we determine that there is greater variability in the human lineage with a significantly increased number of nonsynonymous changes, suggesting human-specific accelerated evolution. Thus, KLF14 may be the first example of an imprinted transcript undergoing accelerated evolution in the human lineage.

  14. A comparison of covalent and non-covalent imprinting strategies for the synthesis of stigmasterol imprinted polymers.

    PubMed

    Hashim, Shima N N S; Boysen, Reinhard I; Schwarz, Lachlan J; Danylec, Basil; Hearn, Milton T W

    2014-09-12

    Non-covalent and covalent imprinting strategies have been investigated for the synthesis of stigmasterol imprinted polymers. The synthesized molecularly imprinted polymers (MIPs) were then evaluated for their recognition and selectivity towards stigmasterol via static and dynamic batch-binding assays and their performance measured against control non-imprinted polymers (NIPs). MIPs prepared using the conventional non-covalent imprinting method displayed little to no binding affinity for stigmasterol under various conditions. In contrast, the application of a covalent imprinting approach using the novel post-synthetically cleavable monomer-template composite stigmasteryl-3-O-methacrylate resulted in the fabrication of a MIP that successfully recognized stigmasterol in both organic and partially aqueous environments. The affinity and selectivity of the covalently prepared MIP was enhanced when undertaken in a partially aqueous environment consisting of an acetonitrile/water (9:1, v/v) solvent mixture. These features have been exploited in a molecularly imprinted solid-phase extraction (MISPE) format, wherein the preferential retention of stigmasterol (with an imprint factor of 12) was demonstrated with 99% recovery in comparison to cholesterol (imprint factor of 6) and ergosterol (imprint factor of 4) while in the presence of several closely related steryl analogues.

  15. [Spectroscopic Study of Salbutamol Molecularly Imprinted Polymers].

    PubMed

    Ren, Hui-peng; Guan, Yu-yu; Dai, Rong-hua; Liu, Guo-yan; Chai, Chun-yan

    2016-02-01

    In order to solve the problem of on-site rapid detection of salbutamol residues in feed and animal products, and develop a new method of fast detection of salbutamol on the basis of the molecular imprinting technology, this article uses the salbutamol (SAL) working as template molecule, methacrylic acid (MAA) working as functional monomer. On this basis, a new type of core-shell type salbutamol molecularly imprinted polymers were prepared with colloidal gold particles as triggering core. Superficial characteristics of the MIPs and the related compounds were investigated by ultraviolet (UV) spectra and infrared (IR) spectra, Raman spectra, Scanning electron microscopy (SEM) respectively. The results indicated that a stable hydrogen bonding complex has been formed between the carboxyl groups of SAL and MA with a matching ratio of 1:1. The complex can be easily eluted by the reagent containing hydrogen bonding. The chemical binding constant K reaches -0.245 x 10⁶ L² · mol⁻². The possible binding sites of the hydrogen bonding was formed between the hydrogen atoms of -COOH in MA and the oxygen atoms of C==O in SAL. IR and Raman spectrum showed that, compared with MA, a significant red shift of -OH absorption peak was manifested in MIPs, which proved that SAL as template molecule occurred a specific bond between MA. Red shift of stretching vibration absorption peak of C==O was also detected in the un-eluted MIPs and obvious energy loss happened, which demonstrated a possible binding sites is SAL intramolecular of C==O atom of oxygen. If the hydrogen atoms of -COOH in MA wanted to generate hydrogen bond. However, the shapes of absorption peak of other functional groups including C==C, C==O, and -OH were very similar both in MIPs and NIPs. Specific cavities were formed after the template molecules in MIPs were removed. It was proved by the adsorption experiment that the specific sites in these cavities highly match with the chemical and space structure of SAL

  16. Quantitative prediction of imprinting factor of molecularly imprinted polymers by artificial neural network

    NASA Astrophysics Data System (ADS)

    Nantasenamat, Chanin; Naenna, Thanakorn; Ayudhya, Chartchalerm Isarankura Na; Prachayasittikul, Virapong

    2005-07-01

    Artificial neural network (ANN) implementing the back-propagation algorithm was applied for the calculation of the imprinting factors (IF) of molecularly imprinted polymers (MIP) as a function of the computed molecular descriptors of template and functional monomer molecules and mobile phase descriptors. The dataset used in our study were obtained from the literature and classified into two distinctive datasets on the basis of the polymer's morphology, irregularly sized MIP and uniformly sized MIP datasets. Results revealed that artificial neural network was able to perform well on datasets derived from uniformly sized MIP ( n=23, r=0.946, RMS=2.944) while performing poorly on datasets derived from irregularly sized MIP ( n=75, r=0.382, RMS=6.123). The superior performance of the uniformly sized MIP dataset over the irregularly sized MIP dataset could be attributed to its more predictable nature owing to the consistency of MIP particles, uniform number and association constant of binding sites, and minimal deviation of the imprinted polymers. The ability to predict the imprinting factor of imprinted polymer prior to performing actual experimental work provide great insights on the feasibility of the interaction between template-functional monomer pairs.

  17. Characterization of molecularly imprinted polymer nanoparticles by photon correlation spectroscopy.

    PubMed

    Malm, Björn; Yoshimatsu, Keiichi; Ye, Lei; Krozer, Anatol

    2014-12-01

    We follow template-binding induced aggregation of nanoparticles enantioselectively imprinted against (S)-propranolol, and the non-imprinted ones, using photon correlation spectroscopy (dynamic light scattering). The method requires no separation steps. We have characterized binding of (R,S)-propranolol to the imprinted polymers and determined the degree of non-specificity by comparing the specific binding with the results obtained using non-imprinted nanoparticles. Using (S)-propranolol as a template for binding to (S)-imprinted nanoparticle, and (R)-propranolol as a non-specific control, we have determined range of concentrations where chiral recognition can be observed. By studying aggregation induced by three analytes related to propranolol, atenolol, betaxolol, and 1-amino-3-(naphthalen-1-yloxy)propan-2-ol, we were able to determine which parts of the template are involved in the specific binding, discuss several details of specific adsorption, and the structure of the imprinted site.

  18. A molecular-imprint nanosensor for ultrasensitive detection of proteins

    NASA Astrophysics Data System (ADS)

    Cai, Dong; Ren, Lu; Zhao, Huaizhou; Xu, Chenjia; Zhang, Lu; Yu, Ying; Wang, Hengzhi; Lan, Yucheng; Roberts, Mary F.; Chuang, Jeffrey H.; Naughton, Michael J.; Ren, Zhifeng; Chiles, Thomas C.

    2010-08-01

    Molecular imprinting is a technique for preparing polymer scaffolds that function as synthetic receptors. Imprinted polymers that can selectively bind organic compounds have proven useful in sensor development. Although creating synthetic molecular-imprinting polymers that recognize proteins remains challenging, nanodevices and nanomaterials show promise in this area. Here, we show that arrays of carbon-nanotube tips with an imprinted non-conducting polymer coating can recognize proteins with subpicogram per litre sensitivity using electrochemical impedance spectroscopy. We have developed molecular-imprinting sensors specific for human ferritin and human papillomavirus derived E7 protein. The molecular-imprinting-based nanosensor can also discriminate between Ca2+-induced conformational changes in calmodulin. This ultrasensitive, label-free electrochemical detection of proteins offers an alternative to biosensors based on biomolecule recognition.

  19. The product of the imprinted H19 gene is an oncofetal RNA.

    PubMed Central

    Ariel, I.; Ayesh, S.; Perlman, E. J.; Pizov, G.; Tanos, V.; Schneider, T.; Erdmann, V. A.; Podeh, D.; Komitowski, D.; Quasem, A. S.; de Groot, N.; Hochberg, A.

    1997-01-01

    AIMS/BACKGROUND: The H19 gene is an imprinted, maternally expressed gene in humans. It is tightly linked and coregulated with the imprinted, paternally expressed gene of insulin-like growth factor 2. The H19 gene product is not translated into protein and functions as an RNA molecule. Although its role has been investigated for more than a decade, its biological function is still not understood fully. H19 is abundantly expressed in many tissues from early stages of embryogenesis through fetal life, and is down regulated postnatally. It is also expressed in certain childhood and adult tumours. This study was designed to screen the expression of H19 in human cancer and its relation to the expression of H19 in the fetus. METHODS: Using in situ hybridisation with a [35S] labelled probe, H19 mRNA was detected in paraffin wax sections of fetal tissues from the first and second trimesters of pregnancy and of a large array of human adult and childhood tumours arising from these tissues. RESULTS: The H19 gene is expressed in tumours arising from tissues which express this gene in fetal life. Its expression in the fetus and in cancer is closely linked with tissue differentiation. CONCLUSIONS: Based on these and previous data, H19 is neither a tumour suppressor gene nor an oncogene. Its product is an oncofetal RNA. The potential use of this RNA as a tumour marker should be evaluated. Images PMID:9208812

  20. Cyclic voltammetry characterization of metal complex imprinted polymer.

    PubMed

    Zeng, Yi Ning; Zheng, Ning; Osborne, Peter G; Li, Yuan Zong; Chang, Wen Bao; Wen, Mei Juan

    2002-01-01

    Polymer capable of specific binding to Cu(2+)-2, 2'-dipyridyl complex was prepared by molecular imprinting technology. The binding specificity of the polymer to the template (Cu(2+)-2, 2'-dipyridyl complex) was investigated by cyclic voltammetric scanning using the carbon paste electrode modified by polymer particles in phosphate buffer solution. Factors that influence rebinding of the imprinted polymer were explored. The results demonstrated that cyclic voltammetry was an efficient approach to explore interactions between template and imprinted polymers.

  1. Development of Improved Crosslinking Monomers for Molecularly Imprinted Materials

    DTIC Science & Technology

    2002-04-05

    Molecular imprinting involves the self-assembled complexation of a substrate to functional monomers to form a pre- polymer complex which is "locked-in" to...on the design of crosslinking monomers for molecular imprinting , we have developed new classes of crosslinked polymers to optimize the performance of...of the design, synthesis, polymerization and performance of these new crosslinking monomers for molecularly imprinted polymers will be reported

  2. Binding Studies on Resins Imprinted with (S)-naproxen

    DTIC Science & Technology

    2002-04-05

    The results are typical of other systems reported in the literature. INTRODUCTION Molecularly imprinted polymers ( MIPs ) are synthetic polymers having...material. These washing experiments were performed on three different MIP -(S)-naproxen samples. A reference non- imprinted polymer was prepared using the...Proceedings. Volume 723. Molecularly Imprinted Materials - Sensors and Other Devices. Symposia Held in San Francisco, California on April 2-5, 2002 To

  3. Molecular Imprinting of Polymeric Core-Shell Nanoparticles

    DTIC Science & Technology

    2002-04-05

    UNCLASSIFIED Defense Technical Information Center Compilation Part Notice ADP013604 TITLE: Molecular Imprinting of Polymeric Core-Shell Nanoparticles...Soc. Symp. Proc. Vol. 723 © 2002 Materials Research Society M3.2 MOLECULAR IMPRINTING OF POLYMERIC CORE-SHELL NANOPARTICLES Natalia P~rez Moral and...rebinding was performed in an organic solvent. INTRODUCTION Molecularly imprinted polymers ( MIPs ) address the need for robust, simple, fast and efficient

  4. Bolt Cutter Blade's Imprint in Toolmarks Examination.

    PubMed

    Volkov, Nikolai; Finkelstein, Nir; Novoselsky, Yehuda; Tsach, Tsadok

    2015-11-01

    Bolt cutters are known as cutting tools which are used for cutting hard objects and materials, such as padlocks and bars. Bolt cutter blades leave their imprint on the cut objects. When receiving a cut object from a crime scene, forensic toolmarks examiners can determine whether the suspected cutting tool was used in a specific crime or not based on class characteristic marks and individual marks that the bolt cutter blades leave on the cut object. The paper presents preliminary results of a study on ten bolt cutters and suggests a quick preliminary examination-the comparison between the blade thickness and the width of the imprint left by the tool on the cut object. Based on the comparison result, if there is not a match, the examiner can eliminate the feasibility of the use of the suspected cutting tool in a specific crime. This examination simplifies and accelerates the comparison procedure.

  5. Imprinting localized plasmons for enhanced solar cells.

    PubMed

    Dunbar, Ricky B; Pfadler, Thomas; Lal, Niraj N; Baumberg, Jeremy J; Schmidt-Mende, Lukas

    2012-09-28

    Imprinted silver nanovoid arrays are investigated via angle-resolved reflectometry to demonstrate their suitability for plasmonic light trapping. Both wavelength- and subwavelength-scale nanovoids are imprinted into standard solar cell architectures to achieve nanostructured metallic electrodes which provide enhanced absorption for improving solar cell performance. The technique is versatile, low-cost and scalable and can be applied to a wide range of organic semiconductors. Absorption features which are independent of incident polarization and weakly dependent on incident angle reveal localized plasmonic modes at the structured interface. Metallic nanostructure-PCPDTBT:PCBM samples demonstrate absorption enhancements of up to 40%. The structured interface provides light trapping, which boosts absorption at wavelengths where the semiconductors absorb poorly.

  6. Gastric mucormycosis: Diagnosis by imprint cytology.

    PubMed

    Tathe, Shilpa P; Dani, Aarti A; Chawhan, Sanjay M; Meshram, Saroj A; Randale, Archana A; Raut, Waman K

    2016-10-01

    The fungi in the order of Mucorales commonly target diabetics and other immunocompromised hosts, producing fatal respiratory and or CNS infections. Gastrointestinal mucormycosis is uncommon and seldom diagnosed in living patients due to nonspecific clinical manifestations. We report a case of gastric mucormycosis in an immmunocompetent male patient, diagnosed by imprint cytology-a rare site and a rare setting. To the best of our knowledge, this is only the second report of gastric mucormycosis being diagnosed on cytology. As the disease is rapidly progressive and often fatal, early diagnosis is critical to the patient survival. Imprint cytology or brush cytology is extremely useful for the rapid diagnosis of gastric mucormycosis as these organisms are morphologically distinct. Familiarity with the cytomorphology of these organisms assists in the correct diagnosis of this disease. Diagn. Cytopathol. 2016;44:820-822. © 2016 Wiley Periodicals, Inc.

  7. Capacitive Biosensors and Molecularly Imprinted Electrodes

    PubMed Central

    Ertürk, Gizem; Mattiasson, Bo

    2017-01-01

    Capacitive biosensors belong to the group of affinity biosensors that operate by registering direct binding between the sensor surface and the target molecule. This type of biosensors measures the changes in dielectric properties and/or thickness of the dielectric layer at the electrolyte/electrode interface. Capacitive biosensors have so far been successfully used for detection of proteins, nucleotides, heavy metals, saccharides, small organic molecules and microbial cells. In recent years, the microcontact imprinting method has been used to create very sensitive and selective biorecognition cavities on surfaces of capacitive electrodes. This chapter summarizes the principle and different applications of capacitive biosensors with an emphasis on microcontact imprinting method with its recent capacitive biosensor applications. PMID:28218689

  8. Development of a Molecularly Imprinted Biomimetic Electrode

    PubMed Central

    Kindschy, Lisa M.; Alocilja, Evangelyn C.

    2007-01-01

    The technique of molecular imprinting produces artificial receptor sites in a polymer that can be used in a biomimetic sensor. This research extends previous studies of a molecularly imprinted polymer (MIP) biomimetic sensor for the small drug theophylline. The presence of theophylline in the biomimetic sensor was monitored by analyzing the peak currents from cyclic voltammetry experiments. The functional working range of the MIP modified electrode was 2 - 4 mM theophylline. The concentration of theophylline that resulted in the best signal was 3 mM. The MIP sensor showed no response to the structurally related molecule caffeine, and therefore was selective to the target analyte theophylline. This research will provide the foundation for future studies that will result in durable biomimetic sensors that can offer a viable alternative to current sensors.

  9. Capacitive Biosensors and Molecularly Imprinted Electrodes.

    PubMed

    Ertürk, Gizem; Mattiasson, Bo

    2017-02-17

    Capacitive biosensors belong to the group of affinity biosensors that operate by registering direct binding between the sensor surface and the target molecule. This type of biosensors measures the changes in dielectric properties and/or thickness of the dielectric layer at the electrolyte/electrode interface. Capacitive biosensors have so far been successfully used for detection of proteins, nucleotides, heavy metals, saccharides, small organic molecules and microbial cells. In recent years, the microcontact imprinting method has been used to create very sensitive and selective biorecognition cavities on surfaces of capacitive electrodes. This chapter summarizes the principle and different applications of capacitive biosensors with an emphasis on microcontact imprinting method with its recent capacitive biosensor applications.

  10. Deciphering bloody imprints through chemical enhancement.

    PubMed

    Doherty, P E; Mooney, D J

    1990-03-01

    Obliterated bloody impressions are occasionally submitted to the crime laboratory, and potentially to the document examiner, for decipherment. Nondestructive methods often lead to inconclusive results in these circumstances. With this point in mind, the researchers explored a series of chemical reagents with the intent to enhance bloody imprints to a legible degree. The reagents selected for this comparison include rhodamine dye, luminol, and Coomassie Blue stain.

  11. Nanoscale molecularly imprinted polymers and method thereof

    DOEpatents

    Hart, Bradley R.; Talley, Chad E.

    2008-06-10

    Nanoscale molecularly imprinted polymers (MIP) having polymer features wherein the size, shape and position are predetermined can be fabricated using an xy piezo stage mounted on an inverted microscope and a laser. Using an AMF controller, a solution containing polymer precursors and a photo initiator are positioned on the xy piezo and hit with a laser beam. The thickness of the polymeric features can be varied from a few nanometers to over a micron.

  12. [Biological decontamination of the imprints obtained from different dental materials].

    PubMed

    Brekhlichuk, P P; Petrov, V O; Bati, V V; Levchuk, O B; Boĭko, N V

    2013-01-01

    Microbiological contamination of the imprints made of alginate ("Ypeen") and silicone material ("Speedex") with and without the correction supplement has been investigated. Streptococcus and Staphylococcus have been estimated to be the most survivable species on the imprint surface, however their concentration differ depending on the type of imprints' material. The strains resistant to antibiotics dominated among all the isolated microorganisms. Bacterial preparations based on Bacillus - Biosporin and Subalin and some extracts of edible plants, fruits and berries can be used in dentistry for the decontamination of imprints obtained by the use of different materials.

  13. Molecularly imprinted polymers for alpha-tocopherol delivery.

    PubMed

    Puoci, Francesco; Cirillo, Giuseppe; Curcio, Manuela; Iemma, Francesca; Parisi, Ortensia Ilaria; Castiglione, Mariarosaria; Picci, Nevio

    2008-05-01

    Biomedical applications of antioxidants have increased dramatically since the link between human diseases and oxidative stress was established. This paper focuses on alpha -tocopherol and on the possibility of employing molecularly imprinted polymers as a controlled release device for alpha-tocopherol in gastrointestinal simulating fluids. Polymers were synthesized using methacrylic acid as functional monomer and ethylene glycol dimethacrylate as cross-linker. Considerable differences in recognition characteristics between imprinted and non-imprinted polymers, both in organic and in aqueous media, were observed. Imprinted polymers bound much more alpha-tocopherol and showed a controlled/sustained drug release capacity in gastrointestinal simulating fluids.

  14. Phospholipid imprinted polymers as selective endotoxin scavengers

    NASA Astrophysics Data System (ADS)

    Sulc, Robert; Szekely, Gyorgy; Shinde, Sudhirkumar; Wierzbicka, Celina; Vilela, Filipe; Bauer, David; Sellergren, Börje

    2017-03-01

    Herein we explore phospholipid imprinting as a means to design receptors for complex glycolipids comprising the toxic lipopolysaccharide endotoxin. A series of polymerizable bis-imidazolium and urea hosts were evaluated as cationic and neutral hosts for phosphates and phosphonates, the latter used as mimics of the phospholipid head groups. The bis-imidazolium hosts interacted with the guests in a cooperative manner leading to the presence of tight and well defined 1:2 ternary complexes. Optimized monomer combinations were subsequently used for imprinting of phosphatidic acid as an endotoxin dummy template. Presence of the aforementioned ternary complexes during polymerization resulted in imprinting of lipid dimers – the latter believed to crudely mimic the endotoxin Lipid A motif. The polymers were characterized with respect to template rebinding, binding affinity, capacity and common structural properties, leading to the identification of polymers which were thereafter subjected to an industrially validated endotoxin removal test. Two of the polymers were capable of removing endotoxin down to levels well below the accepted threshold (0.005 EU/mg API) in pharmaceutical production.

  15. Phospholipid imprinted polymers as selective endotoxin scavengers

    PubMed Central

    Sulc, Robert; Szekely, Gyorgy; Shinde, Sudhirkumar; Wierzbicka, Celina; Vilela, Filipe; Bauer, David; Sellergren, Börje

    2017-01-01

    Herein we explore phospholipid imprinting as a means to design receptors for complex glycolipids comprising the toxic lipopolysaccharide endotoxin. A series of polymerizable bis-imidazolium and urea hosts were evaluated as cationic and neutral hosts for phosphates and phosphonates, the latter used as mimics of the phospholipid head groups. The bis-imidazolium hosts interacted with the guests in a cooperative manner leading to the presence of tight and well defined 1:2 ternary complexes. Optimized monomer combinations were subsequently used for imprinting of phosphatidic acid as an endotoxin dummy template. Presence of the aforementioned ternary complexes during polymerization resulted in imprinting of lipid dimers – the latter believed to crudely mimic the endotoxin Lipid A motif. The polymers were characterized with respect to template rebinding, binding affinity, capacity and common structural properties, leading to the identification of polymers which were thereafter subjected to an industrially validated endotoxin removal test. Two of the polymers were capable of removing endotoxin down to levels well below the accepted threshold (0.005 EU/mg API) in pharmaceutical production. PMID:28303896

  16. Deletions of a differentially methylated CpG island at SNRPN define a putative imprinting control region

    SciTech Connect

    Sutcliffe, J.S.,; Nakao, M.; Beaudet, A.L.

    1994-09-01

    Prader-Willi syndrome (PWS) and Angelman syndrome (AS) are associated with paternal and maternal deficiencies, respectively, of gene expression within human chromosome 15q11-q13, and are caused by deletion, uniparental disomy, or other mutations. Four transcripts designated PAR-5, PAR-7, PAR-1 and PAR-4 were isolated and localized to a region within 300 kb telomeric to the gene encoding small nuclear ribonucleoprotein-associated polypeptide N (SNRPN). Analysis of the transcripts in cultured fibroblasts and lymphoblasts from deletion patients demonstrated that SNRPN, PAR-5 and PAR-1 are expressed exclusively from the paternal chromosome, defining an imprinted domain that spans at least 200 kb. All three imprinted transcripts were absent in cells from three PWS patients (one pair of sibs and one sporadic case) with small deletions that involve a differentially methylated CpG island containing a previously undescribed 5{prime} untranslated exon ({alpha}) of SNRPN. Methylation of the CpG island is specific for the maternal chromosome consistent with paternal expression of the imprinted domain. One deletion, which is benign when maternally transmitted, extends upstream <30 kb from the CpG island, and is associated with altered methylation centromeric to SNRPN, and loss of transcription telomeric to SNRPN, implying the presence of an imprinting control region around the CpG island containing exon {alpha}.

  17. Preparation of protein imprinted materials by hierarchical imprinting techniques and application in selective depletion of albumin from human serum

    PubMed Central

    Liu, Jinxiang; Deng, Qiliang; Tao, Dingyin; Yang, Kaiguang; Zhang, Lihua; Liang, Zhen; Zhang, Yukui

    2014-01-01

    Hierarchical imprinting was developed to prepare the protein imprinted materials, as the artificial antibody, for the selective depletion of HSA from the human serum proteome. Porcine serum albumin (PSA) was employed as the dummy template for the fabrication of the recognition sites. To demonstrate the advantages of the hierarchical imprinting, molecularly imprinted polymers prepared by hierarchical imprinting technique (h-MIPs) were compared with those obtained by bulk imprinting (b-MIPs), in terms of the binding capacity, adsorption kinetics, selectivity and synthesis reproducibility. The binding capacity of h-MIPs could reach 12 mg g−1. And saturation binding could be reached in less than 20 min for the h-MIPs. In the protein mixture, h-MIPs exhibit excellent selectivity for PSA, with imprinting factors as about 3.6, much higher than those for non-template proteins. For the proteomic application, the identified protein group number in serum treated by h-MIPs was increased to 422, which is 21% higher than that obtained from the original serum, meanwhile the identified protein group number for the Albumin Removal kit was only 376. The results demonstrate that protein imprinted polymers prepared by hierarchical imprinting technique, might become the artificial antibodies for the selective depletion of high abundance proteins in proteome study. PMID:24976158

  18. Preparation of protein imprinted materials by hierarchical imprinting techniques and application in selective depletion of albumin from human serum

    NASA Astrophysics Data System (ADS)

    Liu, Jinxiang; Deng, Qiliang; Tao, Dingyin; Yang, Kaiguang; Zhang, Lihua; Liang, Zhen; Zhang, Yukui

    2014-06-01

    Hierarchical imprinting was developed to prepare the protein imprinted materials, as the artificial antibody, for the selective depletion of HSA from the human serum proteome. Porcine serum albumin (PSA) was employed as the dummy template for the fabrication of the recognition sites. To demonstrate the advantages of the hierarchical imprinting, molecularly imprinted polymers prepared by hierarchical imprinting technique (h-MIPs) were compared with those obtained by bulk imprinting (b-MIPs), in terms of the binding capacity, adsorption kinetics, selectivity and synthesis reproducibility. The binding capacity of h-MIPs could reach 12 mg g-1. And saturation binding could be reached in less than 20 min for the h-MIPs. In the protein mixture, h-MIPs exhibit excellent selectivity for PSA, with imprinting factors as about 3.6, much higher than those for non-template proteins. For the proteomic application, the identified protein group number in serum treated by h-MIPs was increased to 422, which is 21% higher than that obtained from the original serum, meanwhile the identified protein group number for the Albumin Removal kit was only 376. The results demonstrate that protein imprinted polymers prepared by hierarchical imprinting technique, might become the artificial antibodies for the selective depletion of high abundance proteins in proteome study.

  19. Heat-Induced Release of Epigenetic Silencing Reveals the Concealed Role of an Imprinted Plant Gene

    PubMed Central

    Sanchez, Diego H.; Paszkowski, Jerzy

    2014-01-01

    Epigenetic mechanisms suppress the transcription of transposons and DNA repeats; however, this suppression can be transiently released under prolonged heat stress. Here we show that the Arabidopsis thaliana imprinted gene SDC, which is silent during vegetative growth due to DNA methylation, is activated by heat and contributes to recovery from stress. SDC activation seems to involve epigenetic mechanisms but not canonical heat-shock perception and signaling. The heat-mediated transcriptional induction of SDC occurs particularly in young developing leaves and is proportional to the level of stress. However, this occurs only above a certain window of absolute temperatures and, thus, resembles a thermal-sensing mechanism. In addition, the re-silencing kinetics during recovery can be entrained by repeated heat stress cycles, suggesting that epigenetic regulation in plants may conserve memory of stress experience. We further demonstrate that SDC contributes to the recovery of plant biomass after stress. We propose that transcriptional gene silencing, known to be involved in gene imprinting, is also co-opted in the specific tuning of SDC expression upon heat stress and subsequent recovery. It is therefore possible that dynamic properties of the epigenetic landscape associated with silenced or imprinted genes may contribute to regulation of their expression in response to environmental challenges. PMID:25411840

  20. Mammalian viviparity: a complex niche in the evolution of genomic imprinting

    PubMed Central

    Keverne, E B

    2014-01-01

    Evolution of mammalian reproductive success has witnessed a strong dependence on maternal resources through placental in utero development. Genomic imprinting, which has an active role in mammalian viviparity, also reveals a biased role for matrilineal DNA in its regulation. The co-existence of three matrilineal generations as one (mother, foetus and post-meiotic oocytes) has provided a maternal niche for transgenerational co-adaptive selection pressures to operate. In utero foetal growth has required increased maternal feeding in advance of foetal energetic demands; the mammary glands are primed for milk production in advance of birth, while the maternal hypothalamus is hormonally primed by the foetal placenta for nest building and post-natal care. Such biological forward planning resulted from maternal–foetal co-adaptation facilitated by co-expression of the same imprinted allele in the developing hypothalamus and placenta. This co-expression is concurrent with the placenta interacting with the adult maternal hypothalamus thereby providing a transgenerational template on which selection pressures may operate ensuring optimal maternalism in this and the next generation. Invasive placentation has further required the maternal immune system to adapt and positively respond to the foetal allotype. Pivotal to these mammalian evolutionary developments, genomic imprinting emerged as a monoallelic gene dosage regulatory mechanism of tightly interconnected gene networks providing developmental genetic stability for in utero development. PMID:24569636

  1. Imprinting regulates mammalian snoRNA-encoding chromatin decondensation and neuronal nucleolar size

    PubMed Central

    Leung, Karen N.; Vallero, Roxanne O.; DuBose, Amanda J.; Resnick, James L.; LaSalle, Janine M.

    2009-01-01

    Imprinting, non-coding RNA and chromatin organization are modes of epigenetic regulation that modulate gene expression and are necessary for mammalian neurodevelopment. The only two known mammalian clusters of genes encoding small nucleolar RNAs (snoRNAs), SNRPN through UBE3A(15q11–q13/7qC) and GTL2(14q32.2/12qF1), are neuronally expressed, localized to imprinted loci and involved in at least five neurodevelopmental disorders. Deficiency of the paternal 15q11–q13 snoRNA HBII-85 locus is necessary to cause the neurodevelopmental disorder Prader–Willi syndrome (PWS). Here we show epigenetically regulated chromatin decondensation at snoRNA clusters in human and mouse brain. An 8-fold allele-specific decondensation of snoRNA chromatin was developmentally regulated specifically in maturing neurons, correlating with HBII-85 nucleolar accumulation and increased nucleolar size. Reciprocal mouse models revealed a genetic and epigenetic requirement of the 35 kb imprinting center (IC) at the Snrpn–Ube3a locus for transcriptionally regulated chromatin decondensation. PWS human brain and IC deletion mouse Purkinje neurons showed significantly decreased nucleolar size, demonstrating the essential role of the 15q11–q13 HBII-85 locus in neuronal nucleolar maturation. These results are relevant to understanding the molecular pathogenesis of multiple human neurodevelopmental disorders, including PWS and some causes of autism. PMID:19656775

  2. Mitochondrial complex II and genomic imprinting in inheritance of paraganglioma tumors.

    PubMed

    Baysal, Bora E

    2013-05-01

    Germ line heterozygous mutations in the structural subunit genes of mitochondrial complex II (succinate dehydrogenase; SDH) and the regulatory gene SDHAF2 predispose to paraganglioma tumors which show constitutive activation of hypoxia inducible pathways. Mutations in SDHD and SDHAF2 cause highly penetrant multifocal tumor development after a paternal transmission, whereas maternal transmission rarely, if ever, leads to tumor development. This transmission pattern is consistent with genomic imprinting. Recent molecular evidence supports a model for tissue-specific imprinted regulation of the SDHD gene by a long range epigenetic mechanism. In addition, there is evidence of SDHB mRNA editing in peripheral blood mononuclear cells and long-term balancing selection operating on the SDHA gene. Regulation of SDH subunit expression by diverse epigenetic mechanisms implicates a crucial dosage-dependent role for SDH in oxygen homeostasis. This article is part of a Special Issue entitled: Respiratory complex II: Role in cellular physiology and disease.

  3. Two progenitor cells for human oogonia inferred from pedigree data and the X-inactivation imprinting model of the fragile-X syndrome.

    PubMed Central

    Laird, C D; Lamb, M M; Thorne, J L

    1990-01-01

    Laird has proposed that the human fragile-X syndrome is caused by abnormal chromosome imprinting. The analysis presented here supports and extends this proposal. Using published pedigrees that include DNA polymorphism (RFLP) data, we establish that the states of the fragile-X mutation termed "imprinted" and "nonimprinted" usually can be distinguished by the level of cytogenetic expression of the fragile-X chromosome. This information is then used to assess the state of the fragile-X allele in carrier progeny of individual women who inherited a nonimprinted fragile-X chromosome. From this assessment, an estimate is made of the frequency, in individual women, of primary oocytes with an imprinted fragile-X chromosome. The results of this analysis provide additional support for the specific model in which chromosome imprinting occurs in a female in, on average, half of her primary oocytes. This is the expected frequency if X-chromosome inactivation is the initial step in the imprinting of the mutant fragile-X allele. Moreover, this analysis suggests a biological explanation for peculiarities of fragile-X inheritance described by others as "clustering" and the "Sherman paradox." We interpret these peculiarities as consequences of a very small number of oogonial progenitor cells. Two progenitor cells for oogonia is the best integer estimate of the number of such cells at the time of the initial event that leads to chromosome imprinting. PMID:1969225

  4. Glomerular-specific imprinting of the mouse Gs{alpha} gene: How does this relate to hormone resistance in Albright hereditary osteodystrophy?

    SciTech Connect

    Williamson, C.M.; Dutton, E.R.; Seymour, A.

    1996-09-01

    The gene for alpha-stimulating guanine-nucleotide binding polypeptide, Gnas, has been considered as a candidate for the imprinting effects ascribed to distal mouse Chromosome (Chr) 2. Its human homologue (GNAS1) appears, from clinical and biochemical studies of patients with Albright hereditary ostodystrophy, to be paternally imprinted. GNAS1 maps to 20q13, a region that shows linkage conservation with distal mouse Chr 2. We have mapped Gnas within the imprinting region on distal Chr 2 by linkage analysis. To establish if Gnas is imprinted, we have looked for expression differences in tissues taken from mice carrying maternal duplication/paternal deficiency for distal Chr 2 (MatDp2) and its reciprocal (PatDp2). RNA in situ hybridization revealed high levels of Gnas mRNA in glomeruli of PatDp2 embryos at late gestation and lower levels in glomeruli of MatDp2 embryos. These results strongly suggest that Gnas is maternally imprinted and suggest that the mouse gene may be imprinted in a manner opposite the predicted in human. 42 refs., 4 figs.

  5. Matrix molecularly imprinted mesoporous sol-gel sorbent for efficient solid-phase extraction of chloramphenicol from milk.

    PubMed

    Samanidou, Victoria; Kehagia, Maria; Kabir, Abuzar; Furton, Kenneth G

    2016-03-31

    Highly selective and efficient chloramphenicol imprinted sol-gel silica based inorganic polymeric sorbent (sol-gel MIP) was synthesized via matrix imprinting approach for the extraction of chloramphenicol in milk. Chloramphenicol was used as the template molecule, 3-aminopropyltriethoxysilane (3-APTES) and triethoxyphenylsilane (TEPS) as the functional precursors, tetramethyl orthosilicate (TMOS) as the cross-linker, isopropanol as the solvent/porogen, and HCl as the sol-gel catalyst. Non-imprinted sol-gel polymer (sol-gel NIP) was synthesized under identical conditions in absence of template molecules for comparison purpose. Both synthesized materials were characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR) and nitrogen adsorption porosimetry, which unambiguously confirmed their significant structural and morphological differences. The synthesized MIP and NIP material