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Tyson HR, Harrison DJ, Higgs MJ, Isles AR, John RM. Deficiency of the paternally-expressed imprinted Peg3 gene in mice has sexually dimorphic consequences for offspring communication and social behaviour. Front Neurosci 2024; 18:1374781. [PMID: 38595977 PMCID: PMC11002209 DOI: 10.3389/fnins.2024.1374781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 03/08/2024] [Indexed: 04/11/2024] Open
Abstract
Introduction Imprinted genes are expressed from one parental allele as a consequence of epigenetic processes initiated in the germline. Consequently, their ability to influence phenotype depends on their parent-of-origin. Recent research suggests that the sex of the individual expressing the imprinted gene is also important. We have previously reported that genetically wildtype (WT) dams carrying and caring for pups mutant for PEG3 exhibit anxiety-like behaviours and their mutant pups show a reduction in ultrasonic vocalisation when separated from their mothers. Sex-specificity was not examined. Methods WT female mice were mated with WT, heterozygous Peg3-/+ or homozygous Peg3-/- studs to generate all WT (control), 50:50 mixed or 100% mutant litters, respectively, followed by behavioural assessment of both dams and their pups. Results We reproduced our original finding that WT dams carrying and caring for 100% mutant litters exhibit postpartum anxiety-like symptoms and delayed pup retrieval. Additionally, these WT dams were found to allocate less time to pup-directed care behaviours relative to controls. Male Peg3-deficient pups demonstrated significantly reduced vocalisation with a more subtle communication deficit in females. Postweaning, male mutants exhibited deficits across a number of key social behaviours as did WT males sharing their environment with mutants. Only modest variations in social behaviour were detected in experimental females. Discussion We have experimentally demonstrated that Peg3 deficiency confined to the offspring causes anxiety in mouse mothers and atypical behaviour including deficits in communication in their male offspring. A male-specific reduction in expression PEG3 in the fetally-derived placenta has previously been associated with maternal depression in human pregnancy. Maternal mood disorders such as depression and anxiety are associated with delays in language development and neuroatypical behaviour more common in sons. Peg3 deficiency could drive the association of maternal and offspring behavioural disorders reported in humans.
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Affiliation(s)
- Hannah R. Tyson
- Biomedicine Division, School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - David J. Harrison
- Biomedicine Division, School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Mathew J. Higgs
- Behavioural Genetics Group, MRC Centre for Neuropsychiatric Genetics and Genomics, Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, United Kingdom
| | - Anthony R. Isles
- Behavioural Genetics Group, MRC Centre for Neuropsychiatric Genetics and Genomics, Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, United Kingdom
| | - Rosalind M. John
- Biomedicine Division, School of Biosciences, Cardiff University, Cardiff, United Kingdom
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2
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Kim J, Frey WD, Sharma K, Ghimire S, Teruyama R, Stubbs L. Allele-specific enhancer interaction at the Peg3 imprinted domain. PLoS One 2019; 14:e0224287. [PMID: 31639176 PMCID: PMC6804975 DOI: 10.1371/journal.pone.0224287] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 10/09/2019] [Indexed: 12/20/2022] Open
Abstract
The parental allele specificity of mammalian imprinted genes has been evolutionarily well conserved, although its functional constraints and associated mechanisms are not fully understood. In the current study, we generated a mouse mutant with switched active alleles driving the switch from paternal-to-maternal expression for Peg3 and the maternal-to-paternal expression for Zim1. The expression levels of Peg3 and Zim1, but not the spatial expression patterns, within the brain showed clear differences between wild type and mutant animals. We identified putative enhancers localized upstream of Peg3 that displayed allele-biased DNA methylation, and that also participate in allele-biased chromosomal conformations with regional promoters. Most importantly, these data suggest for the first time that long-distance enhancers may contribute to allelic expression within imprinted domains through allele-biased interactions with regional promoters.
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Affiliation(s)
- Joomyeong Kim
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, United States of America
- * E-mail:
| | - Wesley D. Frey
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, United States of America
| | - Kaustubh Sharma
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, United States of America
| | - Subash Ghimire
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, United States of America
| | - Ryoichi Teruyama
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, United States of America
| | - Lisa Stubbs
- Cell and Developmental Biology, Institute for Genomic Biology, University of Illinois, Urbana, Illinois, United States of America
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3
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Molecular codes and in vitro generation of hypocretin and melanin concentrating hormone neurons. Proc Natl Acad Sci U S A 2019; 116:17061-17070. [PMID: 31375626 PMCID: PMC6708384 DOI: 10.1073/pnas.1902148116] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Hypocretin/orexin (HCRT) and melanin concentrating hormone (MCH) neuropeptides are exclusively produced by the lateral hypothalamus and play important roles in sleep, metabolism, reward, and motivation. Loss of HCRT (ligands or receptors) causes the sleep disorder narcolepsy with cataplexy in humans and in animal models. How these neuropeptides are produced and involved in diverse functions remain unknown. Here, we developed methods to sort and purify HCRT and MCH neurons from the mouse late embryonic hypothalamus. RNA sequencing revealed key factors of fate determination for HCRT (Peg3, Ahr1, Six6, Nr2f2, and Prrx1) and MCH (Lmx1, Gbx2, and Peg3) neurons. Loss of Peg3 in mice significantly reduces HCRT and MCH cell numbers, while knock-down of a Peg3 ortholog in zebrafish completely abolishes their expression, resulting in a 2-fold increase in sleep amount. We also found that loss of HCRT neurons in Hcrt-ataxin-3 mice results in a specific 50% decrease in another orexigenic neuropeptide, QRFP, that might explain the metabolic syndrome in narcolepsy. The transcriptome results were used to develop protocols for the production of HCRT and MCH neurons from induced pluripotent stem cells and ascorbic acid was found necessary for HCRT and BMP7 for MCH cell differentiation. Our results provide a platform to understand the development and expression of HCRT and MCH and their multiple functions in health and disease.
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Correra RM, Ollitrault D, Valente M, Mazzola A, Adalsteinsson BT, Ferguson-Smith AC, Marazzi G, Sassoon DA. The imprinted gene Pw1/Peg3 regulates skeletal muscle growth, satellite cell metabolic state, and self-renewal. Sci Rep 2018; 8:14649. [PMID: 30279563 PMCID: PMC6168517 DOI: 10.1038/s41598-018-32941-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 09/18/2018] [Indexed: 12/16/2022] Open
Abstract
Pw1/Peg3 is an imprinted gene expressed from the paternally inherited allele. Several imprinted genes, including Pw1/Peg3, have been shown to regulate overall body size and play a role in adult stem cells. Pw1/Peg3 is expressed in muscle stem cells (satellite cells) as well as a progenitor subset of muscle interstitial cells (PICs) in adult skeletal muscle. We therefore examined the impact of loss-of-function of Pw1/Peg3 during skeletal muscle growth and in muscle stem cell behavior. We found that constitutive loss of Pw1/Peg3 function leads to a reduced muscle mass and myofiber number. In newborn mice, the reduction in fiber number is increased in homozygous mutants as compared to the deletion of only the paternal Pw1/Peg3 allele, indicating that the maternal allele is developmentally functional. Constitutive and a satellite cell-specific deletion of Pw1/Peg3, revealed impaired muscle regeneration and a reduced capacity of satellite cells for self-renewal. RNA sequencing analyses revealed a deregulation of genes that control mitochondrial function. Consistent with these observations, Pw1/Peg3 mutant satellite cells displayed increased mitochondrial activity coupled with accelerated proliferation and differentiation. Our data show that Pw1/Peg3 regulates muscle fiber number determination during fetal development in a gene-dosage manner and regulates satellite cell metabolism in the adult.
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Affiliation(s)
- Rosa Maria Correra
- UMR S 1166 INSERM (Stem Cells and Regenerative Medicine Team), University of Pierre and Marie Curie Paris VI, Paris, 75634, France
- Institute of Cardiometabolism and Nutrition (ICAN), Paris, 75013, France
| | - David Ollitrault
- UMR S 1166 INSERM (Stem Cells and Regenerative Medicine Team), University of Pierre and Marie Curie Paris VI, Paris, 75634, France
- Institute of Cardiometabolism and Nutrition (ICAN), Paris, 75013, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unit 970, Paris Cardiovascular Research Center, Université René Descartes Paris, Paris, France
| | - Mariana Valente
- UMR S 1166 INSERM (Stem Cells and Regenerative Medicine Team), University of Pierre and Marie Curie Paris VI, Paris, 75634, France
- Institute of Cardiometabolism and Nutrition (ICAN), Paris, 75013, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unit 970, Paris Cardiovascular Research Center, Université René Descartes Paris, Paris, France
| | - Alessia Mazzola
- UMR S 1166 INSERM (Stem Cells and Regenerative Medicine Team), University of Pierre and Marie Curie Paris VI, Paris, 75634, France
- Institute of Cardiometabolism and Nutrition (ICAN), Paris, 75013, France
| | - Bjorn T Adalsteinsson
- Department of Physiology Development and Neuroscience, Downing Street, University of Cambridge, Cambridge, United Kingdom
| | - Anne C Ferguson-Smith
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, United Kingdom
| | - Giovanna Marazzi
- UMR S 1166 INSERM (Stem Cells and Regenerative Medicine Team), University of Pierre and Marie Curie Paris VI, Paris, 75634, France.
- Institute of Cardiometabolism and Nutrition (ICAN), Paris, 75013, France.
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unit 970, Paris Cardiovascular Research Center, Université René Descartes Paris, Paris, France.
| | - David A Sassoon
- UMR S 1166 INSERM (Stem Cells and Regenerative Medicine Team), University of Pierre and Marie Curie Paris VI, Paris, 75634, France.
- Institute of Cardiometabolism and Nutrition (ICAN), Paris, 75013, France.
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unit 970, Paris Cardiovascular Research Center, Université René Descartes Paris, Paris, France.
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5
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Abstract
Mouse Peg3 encodes a DNA-binding protein involved in the milk letdown process. In the current study, we tested whether PEG3 controls the expression of the oxytocin receptor gene. According to the results, PEG3 directly binds to a genomic region within the 3rd exon of Oxtr, which contains a DNA-binding motif for PEG3. In nursing female mice, removal of PEG3 resulted in the increased expression of Oxtr in mammary epithelial cells and also in the hypothalamus. This suggests a repressor role of PEG3 in the expression of Oxtr in these tissues. Overall, this study suggests that Peg3 may function as a direct transcriptional regulator for Oxtr expression that acts to moderate the milk letdown process.
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6
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He H, Ye A, Perera BPU, Kim J. YY1's role in the Peg3 imprinted domain. Sci Rep 2017; 7:6427. [PMID: 28743993 PMCID: PMC5526879 DOI: 10.1038/s41598-017-06817-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 06/19/2017] [Indexed: 11/30/2022] Open
Abstract
The ICR (Imprinting Control Region) of the Peg3 (Paternally Expressed Gene 3) domain contains an unusual cluster of YY1 binding sites. In the current study, these YY1 binding sites were mutated to characterize the unknown roles in the mouse Peg3 domain. According to the results, paternal and maternal transmission of the mutant allele did not cause any major effect on the survival of the pups. In the mutants, the maternal-specific DNA methylation on the ICR was properly established and maintained, causing no major effect on the imprinting of the domain. In contrast, the paternal transmission resulted in changes in the expression levels of several genes: down-regulation of Peg3 and Usp29 and up-regulation of Zim1. These changes were more pronounced during the neonatal stage than during the adult stage. In the case of Peg3 and Zim1, the levels of the observed changes were also different between males and females, suggesting the different degrees of YY1 involvement between two sexes. Overall, the results indicated that YY1 is mainly involved in controlling the transcriptional levels, but not the DNA methylation, of the Peg3 domain.
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Affiliation(s)
- Hongzhi He
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - An Ye
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA
| | | | - Joomyeong Kim
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA.
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7
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Kim J, He H, Kim H. Inversion of the imprinting control region of the Peg3 domain. PLoS One 2017; 12:e0181591. [PMID: 28719641 PMCID: PMC5515438 DOI: 10.1371/journal.pone.0181591] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 07/03/2017] [Indexed: 11/19/2022] Open
Abstract
The imprinting of the mouse Peg3 domain is controlled through a 4-kb genomic region encompassing the bidirectional promoter and 1st exons of Peg3 and Usp29. In the current study, this ICR was inverted to test its orientation dependency for the transcriptional and imprinting control of the Peg3 domain. The inversion resulted in the exchange of promoters and 1st exons between Peg3 and Usp29. Paternal transmission of this inversion caused 10-fold down-regulation of Peg3 and 2-fold up-regulation of Usp29 in neonatal heads, consistent with its original promoter strength in each direction. The paternal transmission also resulted in reduced body size among the animals, which was likely contributed by the dramatic down-regulation of Peg3. Transmission through either allele caused no changes in the DNA methylation and imprinting status of the Peg3 domain except that Zfp264 became bi-allelic through the maternal transmission. Overall, the current study suggests that the orientation of the Peg3-ICR may play no role in its allele-specific DNA methylation, but very critical for the transcriptional regulation of the entire imprinted domain.
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Affiliation(s)
- Joomyeong Kim
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, United States of America
- * E-mail:
| | - Hongzhi He
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, United States of America
| | - Hana Kim
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, United States of America
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8
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Bretz CL, Langohr IM, Lee S, Kim J. Epigenetic instability at imprinting control regions in a Kras(G12D)-induced T-cell neoplasm. Epigenetics 2016; 10:1111-20. [PMID: 26507119 DOI: 10.1080/15592294.2015.1110672] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
Although aberrant DNA methylation within imprinted domains has been reported in a variety of neoplastic diseases, it remains largely uncharacterized in the context of carcinogenesis. In this study, we induced T-cell lymphoma in mice by employing a breeding scheme involving mouse strains, LSL-Kras(G12D) and MMTV-Cre. We then systematically surveyed imprinted domains for DNA methylation changes during tumor progression using combined bisulfite restriction analysis and NGS-based bisulfite sequencing. We detected hyper- or hypo-methylation at the imprinting control regions (ICRs) of the Dlk1, Peg10, Peg3, Grb10, and Gnas domains. These DNA methylation changes at ICRs were more prevalent and consistent than those observed at the promoter regions of well-known tumor suppressors, such as Mgmt, Fhit, and Mlh1. Thus, the changes observed at these imprinted domains are the outcome of isolated incidents affecting DNA methylation settings. Within imprinted domains, DNA methylation changes tend to be restricted to ICRs as nearby somatic differentially methylated regions and promoter regions experience no change. Furthermore, detailed analyses revealed that small cis-regulatory elements within ICRs tend to be resistant to DNA methylation changes, suggesting potential protection by unknown trans-factors. Overall, this study demonstrates that DNA methylation changes at ICRs are dynamic during carcinogenesis and advocates that detection of aberrant DNA methylation at ICRs may serve as a biomarker to enhance diagnostic procedures.
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Affiliation(s)
- Corey L Bretz
- a Department of Biological Sciences ; Louisiana State University ; Baton Rouge ; LA , USA
| | - Ingeborg M Langohr
- b Louisiana State University School of Veterinary Medicine ; Department of Pathobiological Sciences ; Baton Rouge ; LA , USA
| | - Suman Lee
- a Department of Biological Sciences ; Louisiana State University ; Baton Rouge ; LA , USA
| | - Joomyeong Kim
- a Department of Biological Sciences ; Louisiana State University ; Baton Rouge ; LA , USA
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9
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Tsanov N, Samacoits A, Chouaib R, Traboulsi AM, Gostan T, Weber C, Zimmer C, Zibara K, Walter T, Peter M, Bertrand E, Mueller F. smiFISH and FISH-quant - a flexible single RNA detection approach with super-resolution capability. Nucleic Acids Res 2016; 44:e165. [PMID: 27599845 PMCID: PMC5159540 DOI: 10.1093/nar/gkw784] [Citation(s) in RCA: 232] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 08/26/2016] [Indexed: 11/12/2022] Open
Abstract
Single molecule FISH (smFISH) allows studying transcription and RNA localization by imaging individual mRNAs in single cells. We present smiFISH (single molecule inexpensive FISH), an easy to use and flexible RNA visualization and quantification approach that uses unlabelled primary probes and a fluorescently labelled secondary detector oligonucleotide. The gene-specific probes are unlabelled and can therefore be synthesized at low cost, thus allowing to use more probes per mRNA resulting in a substantial increase in detection efficiency. smiFISH is also flexible since differently labelled secondary detector probes can be used with the same primary probes. We demonstrate that this flexibility allows multicolor labelling without the need to synthesize new probe sets. We further demonstrate that the use of a specific acrydite detector oligonucleotide allows smiFISH to be combined with expansion microscopy, enabling the resolution of transcripts in 3D below the diffraction limit on a standard microscope. Lastly, we provide improved, fully automated software tools from probe-design to quantitative analysis of smFISH images. In short, we provide a complete workflow to obtain automatically counts of individual RNA molecules in single cells.
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Affiliation(s)
- Nikolay Tsanov
- Institut de Génétique Moléculaire de Montpellier, UMR 5535 CNRS, 1919 route de Mende, 34293 Montpellier cedex 5, France.,Institut de Génétique Moléculaire de Montpellier, UMR 5535 CNRS, 1919 route de Mende, 34293 Montpellier cedex 5, France
| | - Aubin Samacoits
- Unité Imagerie et Modélisation, Institut Pasteur and CNRS UMR 3691, 28 rue du Docteur Roux, 75015 Paris, France.,C3BI, USR 3756 IP CNRS - Paris, France
| | - Racha Chouaib
- Institut de Génétique Moléculaire de Montpellier, UMR 5535 CNRS, 1919 route de Mende, 34293 Montpellier cedex 5, France.,Université de Montpellier, 163 rue Auguste Broussonnet, 34090 Montpellier, France.,ER045, Laboratory of Stem Cells, DSST, PRASE, Lebanese University, Beirut, Lebanon
| | - Abdel-Meneem Traboulsi
- Institut de Génétique Moléculaire de Montpellier, UMR 5535 CNRS, 1919 route de Mende, 34293 Montpellier cedex 5, France.,Université de Montpellier, 163 rue Auguste Broussonnet, 34090 Montpellier, France
| | - Thierry Gostan
- Institut de Génétique Moléculaire de Montpellier, UMR 5535 CNRS, 1919 route de Mende, 34293 Montpellier cedex 5, France.,Université de Montpellier, 163 rue Auguste Broussonnet, 34090 Montpellier, France
| | - Christian Weber
- Unité Imagerie et Modélisation, Institut Pasteur and CNRS UMR 3691, 28 rue du Docteur Roux, 75015 Paris, France.,C3BI, USR 3756 IP CNRS - Paris, France
| | - Christophe Zimmer
- Unité Imagerie et Modélisation, Institut Pasteur and CNRS UMR 3691, 28 rue du Docteur Roux, 75015 Paris, France.,C3BI, USR 3756 IP CNRS - Paris, France
| | - Kazem Zibara
- ER045, Laboratory of Stem Cells, DSST, PRASE, Lebanese University, Beirut, Lebanon.,Biology Department, Faculty of Sciences-I, Lebanese University, Beirut, Lebanon
| | - Thomas Walter
- MINES ParisTech, PSL-Research University, CBIO-Centre for Computational Biology, 77300 Fontainebleau, France.,Institut Curie, 75248 Paris Cedex, France.,INSERM, U900, 75248 Paris Cedex, France
| | - Marion Peter
- Institut de Génétique Moléculaire de Montpellier, UMR 5535 CNRS, 1919 route de Mende, 34293 Montpellier cedex 5, France .,Université de Montpellier, 163 rue Auguste Broussonnet, 34090 Montpellier, France
| | - Edouard Bertrand
- Institut de Génétique Moléculaire de Montpellier, UMR 5535 CNRS, 1919 route de Mende, 34293 Montpellier cedex 5, France .,Université de Montpellier, 163 rue Auguste Broussonnet, 34090 Montpellier, France
| | - Florian Mueller
- Unité Imagerie et Modélisation, Institut Pasteur and CNRS UMR 3691, 28 rue du Docteur Roux, 75015 Paris, France .,C3BI, USR 3756 IP CNRS - Paris, France
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A Novel Mutant Allele of Pw1/Peg3 Does Not Affect Maternal Behavior or Nursing Behavior. PLoS Genet 2016; 12:e1006053. [PMID: 27187722 PMCID: PMC4871489 DOI: 10.1371/journal.pgen.1006053] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 04/23/2016] [Indexed: 11/25/2022] Open
Abstract
Parental imprinting is a mammalian-specific form of epigenetic regulation in which one allele of a gene is silenced depending on its parental origin. Parentally imprinted genes have been shown to play a role in growth, metabolism, cancer, and behavior. Although the molecular mechanisms underlying parental imprinting have been largely elucidated, the selective advantage of silencing one allele remains unclear. The mutant phenotype of the imprinted gene, Pw1/Peg3, provides a key example to illustrate the hypothesis on a coadaptation between mother and offspring, in which Pw1/Peg3 is required for a set of essential maternal behaviors, such as nursing, nest building, and postnatal care. We have generated a novel Pw1/Peg3 mutant allele that targets the last exon for the PW1 protein that contains >90% of the coding sequence resulting in a loss of Pw1/Peg3 expression. In contrast to previous reports that have targeted upstream exons, we observe that maternal behavior and lactation are not disrupted upon loss of Pw1/Peg3. Both paternal and homozygous Pw1/Peg3 mutant females nurse and feed their pups properly and no differences are detected in either oxytocin neuron number or oxytocin plasma levels. In addition, suckling capacities are normal in mutant pups. Consistent with previous reports, we observe a reduction of postnatal growth. These results support a general role for Pw1/Peg3 in the regulation of body growth but not maternal care and lactation. Parental genomic imprinting is a mammalian-specific form of epigenetic control that regulates genes differently depending upon whether they are paternally or maternally inherited. The selective advantage of genomic imprinting is poorly understood and has been the subject of numerous theories. In the last several decades, mouse genetic studies have revealed that imprinted genes regulate embryonic and postnatal growth, metabolism, stem cells, neuronal functions, and most notably, behavior. The paternally expressed gene Pw1/Peg3 was one of the first imprinted genes shown to influence maternal behaviors essential for pup survival and growth. Several key studies have demonstrated that Pw1/Peg3 is required for proper nursing and milk ejection by the mother and suckling by the offspring. These previous observations have provided a strong support for the coadaptation theory of imprinting, which proposes that imprinted genes regulate the use of resources between mother and progeny to optimize their survival and future reproductive success. Here we describe that Pw1/Peg3 mutant females exhibit intact maternal behaviors and do not display milk ejection defects. In addition, mutant pups are able to nurse properly.
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11
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Alternative promoters of Peg3 with maternal specificity. Sci Rep 2016; 6:24438. [PMID: 27075691 PMCID: PMC4830991 DOI: 10.1038/srep24438] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Accepted: 03/23/2016] [Indexed: 12/15/2022] Open
Abstract
Peg3 (paternally expressed gene 3) is an imprinted gene localized within an evolutionarily conserved 500-kb domain in human chromosome 19q13.4 and mouse proximal chromosome 7. In the current study, we have identified three alternative promoters for mouse Peg3 and one alternative promoter for human PEG3. These alternative promoters are localized within the 200-kb upstream region of human and mouse PEG3, which is well conserved and thus predicted to harbor several cis-regulatory elements for the PEG3 domain. In the mouse, two of these alternative promoters drive maternal-specific expression of Peg3 specifically in the hypothalamus of the adult brain, while the remaining third promoter drives bi-allelic expression of Peg3 with a paternal bias only in the neonatal-stage brain. In human, an alternative transcript is also detected at relatively very low levels in adult brain and placenta. Overall, the identification of alternative promoters in both mouse and human models suggests that these alternative promoters may be functionally selected features for the PEG3 imprinted domain during mammalian evolution.
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12
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Lee S, Ye A, Kim J. DNA-Binding Motif of the Imprinted Transcription Factor PEG3. PLoS One 2015; 10:e0145531. [PMID: 26692216 PMCID: PMC4686966 DOI: 10.1371/journal.pone.0145531] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 12/04/2015] [Indexed: 01/04/2023] Open
Abstract
Peg3 is an imprinted gene that is predicted to encode a DNA-binding zinc finger protein. This was previously demonstrated through Chromatin ImmunoPrecipitation-based Sequencing experiments. In the current study, we reanalyzed the previous ChIP-Seq results and further characterized the DNA-binding motif of PEG3. According to the results, PEG3 binds to the promoters and enhancers of a subset of genes that are closely associated with the known functions of Peg3. Some of these identified targets include Tufm, Mrpl45, Cry2, Per1, Slc25a29 and Slc38a2. With this set of targets, we derived a DNA-binding motif of PEG3, 5'-GTGGCAGT-3', which also provides a tabulated matrix that can be used for predicting other unknown genomic targets. Among the newly identified targets, we analyzed in detail the two loci, Slc38a2 and Slc38a4, which are known to be involved in neutral amino acid transport. The results indicated that PEG3 likely functions as a transcriptional repressor for these two loci. Overall, the current study provides a set of genomic targets and also redefines the DNA-binding motif for the imprinted transcription factor PEG3.
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Affiliation(s)
- Suman Lee
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, 70803, United States of America
| | - An Ye
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, 70803, United States of America
| | - Joomyeong Kim
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, 70803, United States of America
- * E-mail:
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