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Gül S, Vloeberghs V, Gies I, Goossens E. Testicular mosaicism in non-mosaic postpubertal Klinefelter patients with focal spermatogenesis and in non-mosaic prepubertal Klinefelter boys. Hum Reprod 2024; 39:2210-2220. [PMID: 39198007 DOI: 10.1093/humrep/deae192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 06/20/2024] [Indexed: 09/01/2024] Open
Abstract
STUDY QUESTION Do testis-specific cells have a normal karyotype in non-mosaic postpubertal Klinefelter syndrome (KS) patients with focal spermatogenesis and in non-mosaic prepubertal KS boys? SUMMARY ANSWER Spermatogonia have a 46, XY karyotype, and Sertoli cells surrounding these spermatogonia in postpubertal patients also have a 46, XY karyotype, whereas, in prepubertal KS boys, Sertoli cells surrounding the spermatogonia still have a 47, XXY karyotype. WHAT IS KNOWN ALREADY A significant proportion of patients with non-mosaic KS can have children by using assisted reproductive techniques thanks to focal spermatogenesis. However, the karyotype of the cells that are able to support focal spermatogenesis has not been revealed. STUDY DESIGN, SIZE, DURATION Testicular biopsy samples from non-mosaic KS patients were included in the study. Karyotyping for sex chromosomes in testis-specific cells was performed by immunohistochemical analysis of inactive X (Xi) chromosome and/or fluorescent in situ hybridization (FISH) analysis of chromosomes 18, X, and Y. PARTICIPANTS/MATERIALS, SETTING, METHODS A total of 22 KS patients (17 postpubertal and 5 prepubertal) who were non-mosaic according to lymphocyte karyotype analysis, were included in the study. After tissue processing, paraffin embedding, and sectioning, the following primary antibodies were used for cell-specific analysis and Xi detection; one section was stained with MAGE A4 for spermatogonia, SOX9 for Sertoli cells, and H3K27me3 for Xi; the other one was stained with CYP17A1 for Leydig cells, ACTA2 for peritubular myoid cells, and H3K27me3 for Xi. Xi negative (Xi-) somatic cells (i.e. Sertoli cells, Leydig cells, and peritubular myoid cells) were evaluated as having the 46, XY karyotype; Xi positive (Xi+) somatic cells were evaluated as having the 47, XXY. FISH stain for chromosomes 18, X, and Y was performed on the same sections to investigate the karyotype of spermatogonia and to validate the immunohistochemistry results for somatic cells. MAIN RESULTS AND THE ROLE OF CHANCE According to our data, all spermatogonia in both postpubertal and prepubertal non-mosaic KS patients seem to have 46, XY karyotype. However, while the Sertoli cells surrounding spermatogonia in postpubertal samples also had a 46, XY karyotype, the Sertoli cells surrounding spermatogonia in prepubertal samples had a 47, XXY karyotype. In addition, while the Sertoli cells in some of the Sertoli cell-only tubules had 46, XY karyotype, the Sertoli cells in some of the other Sertoli cell-only tubules had 47, XXY karyotype in postpubertal samples. In contrast to the postpubertal samples, Sertoli cells in all tubules in the prepubertal samples had the 47, XXY karyotype. Our data also suggest that germ cells lose the extra X chromosome during embryonic, fetal, or neonatal life, while Sertoli cells lose it around puberty. Peritubular myoid cells and Leydig cells may also be mosaic in both postpubertal patients and prepubertal boys, but it requires further investigation. LIMITATIONS, REASONS FOR CAUTION The number of prepubertal testicle samples containing spermatogonia is limited, so more samples are needed for a definitive conclusion. The fact that not all the cell nuclei coincide with the section plane limits the accurate detection of X chromosomes by immunohistochemistry and FISH in some cells. To overcome this limitation, X chromosome analysis could be performed by different techniques on intact cells isolated from fresh tissue. Additionally, there is no evidence that X chromosome inactivation reoccurs after activation of the Xi during germ cell migration during embryogenesis, limiting the prediction of X chromosome content in germ cells by H3K27me3. WIDER IMPLICATIONS OF THE FINDINGS Our findings will lay the groundwork for new clinically important studies on exactly when and by which mechanism an extra X chromosome is lost in spermatogonia and Sertoli cells. STUDY FUNDING/COMPETING INTEREST(S) This study was funded by The Scientific and Technological Research Council of Türkiye (TUBITAK) (2219 - International Postdoctoral Research Fellowship Program for Turkish Citizens) and the Strategic Research Program (SRP89) from the Vrije Universiteit Brussel. The authors declare no competing interests. TRIAL REGISTRATION NUMBER N/A.
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Affiliation(s)
- Semir Gül
- Biology of the Testis Lab, Research Group Genetics, Reproduction and Development (GRAD), Vrije Universiteit Brussel (VUB), Brussels, Belgium
- Faculty of Medicine, Histology and Embryology Department, Malatya Turgut Özal University, Malatya, Turkey
- Faculty of Medicine, Histology and Embryology Department, , Tokat Gaziosmanpaşa University, Tokat, Türkiye
| | - Veerle Vloeberghs
- Universitair Ziekenhuis Brussel (UZ Brussel), Brussels IVF, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Inge Gies
- Division of Pediatric Endocrinology, Department of Pediatrics, Universitair Ziekenhuis Brussel (UZ Brussel), Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Ellen Goossens
- Biology of the Testis Lab, Research Group Genetics, Reproduction and Development (GRAD), Vrije Universiteit Brussel (VUB), Brussels, Belgium
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2
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Du Z, Hu L, Zou Z, Liu M, Li Z, Lu X, Harris C, Xiang Y, Chen F, Yu G, Xu K, Kong F, Xu Q, Huang B, Liu L, Fan Q, Wang H, Kalantry S, Xie W. Stepwise de novo establishment of inactive X chromosome architecture in early development. Nat Genet 2024:10.1038/s41588-024-01897-2. [PMID: 39256583 DOI: 10.1038/s41588-024-01897-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 08/07/2024] [Indexed: 09/12/2024]
Abstract
X chromosome inactivation triggers a dramatic reprogramming of transcription and chromosome architecture. However, how the chromatin organization of inactive X chromosome is established de novo in vivo remains elusive. Here, we identified an Xist-separated megadomain structure (X-megadomains) on the inactive X chromosome in mouse extraembryonic lineages and extraembryonic endoderm (XEN) cell lines, and transiently in the embryonic lineages, before Dxz4-delineated megadomain formation at later stages in a strain-specific manner. X-megadomain boundary coincides with strong enhancer activities and cohesin binding in an Xist regulatory region required for proper Xist activation in early embryos. Xist regulatory region disruption or cohesin degradation impaired X-megadomains in extraembryonic endoderm cells and caused ectopic activation of regulatory elements and genes near Xist, indicating that cohesin loading at regulatory elements promotes X-megadomains and confines local gene activities. These data reveal stepwise X chromosome folding and transcriptional regulation to achieve both essential gene activation and global silencing during the early stages of X chromosome inactivation.
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Affiliation(s)
- Zhenhai Du
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, New Cornerstone Science Laboratory, School of Life Sciences, Tsinghua University, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Liangjun Hu
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, New Cornerstone Science Laboratory, School of Life Sciences, Tsinghua University, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Zhuoning Zou
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, New Cornerstone Science Laboratory, School of Life Sciences, Tsinghua University, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Meishuo Liu
- Tsinghua-Peking Center for Life Sciences, Beijing, China
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Zihan Li
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, New Cornerstone Science Laboratory, School of Life Sciences, Tsinghua University, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Xukun Lu
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, New Cornerstone Science Laboratory, School of Life Sciences, Tsinghua University, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Clair Harris
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Yunlong Xiang
- Department of Cell Biology and Genetics, School of Basic Medical Sciences, Chongqing Medical University, Chongqing, China
| | - Fengling Chen
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, New Cornerstone Science Laboratory, School of Life Sciences, Tsinghua University, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Guang Yu
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, New Cornerstone Science Laboratory, School of Life Sciences, Tsinghua University, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Kai Xu
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, New Cornerstone Science Laboratory, School of Life Sciences, Tsinghua University, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Feng Kong
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, New Cornerstone Science Laboratory, School of Life Sciences, Tsinghua University, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Qianhua Xu
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, New Cornerstone Science Laboratory, School of Life Sciences, Tsinghua University, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Bo Huang
- Zhejiang Provincial Key Laboratory of Pancreatic Disease, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Ling Liu
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, New Cornerstone Science Laboratory, School of Life Sciences, Tsinghua University, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Qiang Fan
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, New Cornerstone Science Laboratory, School of Life Sciences, Tsinghua University, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Haifeng Wang
- Tsinghua-Peking Center for Life Sciences, Beijing, China.
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing, China.
| | - Sundeep Kalantry
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, USA.
| | - Wei Xie
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, New Cornerstone Science Laboratory, School of Life Sciences, Tsinghua University, Beijing, China.
- Tsinghua-Peking Center for Life Sciences, Beijing, China.
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Cecalev D, Viçoso B, Galupa R. Compensation of gene dosage on the mammalian X. Development 2024; 151:dev202891. [PMID: 39140247 PMCID: PMC11361640 DOI: 10.1242/dev.202891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/15/2024]
Abstract
Changes in gene dosage can have tremendous evolutionary potential (e.g. whole-genome duplications), but without compensatory mechanisms, they can also lead to gene dysregulation and pathologies. Sex chromosomes are a paradigmatic example of naturally occurring gene dosage differences and their compensation. In species with chromosome-based sex determination, individuals within the same population necessarily show 'natural' differences in gene dosage for the sex chromosomes. In this Review, we focus on the mammalian X chromosome and discuss recent new insights into the dosage-compensation mechanisms that evolved along with the emergence of sex chromosomes, namely X-inactivation and X-upregulation. We also discuss the evolution of the genetic loci and molecular players involved, as well as the regulatory diversity and potentially different requirements for dosage compensation across mammalian species.
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Affiliation(s)
- Daniela Cecalev
- Molecular, Cellular and Developmental Biology (MCD) Unit, Centre de Biologie Intégrative (CBI), University of Toulouse, CNRS, UPS, 31062, Toulouse, France
| | - Beatriz Viçoso
- Institute of Science and Technology Austria (ISTA), Am Campus 1, Klosterneuburg 3400, Austria
| | - Rafael Galupa
- Molecular, Cellular and Developmental Biology (MCD) Unit, Centre de Biologie Intégrative (CBI), University of Toulouse, CNRS, UPS, 31062, Toulouse, France
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4
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Deng Z, Zhang Y, Xie X, Li H, Guo H, Ni X, Li X. Transcriptomic and proteomic elucidation of Z chromosome dosage compensation in Helicoverpa armigera. INSECT MOLECULAR BIOLOGY 2024. [PMID: 38949741 DOI: 10.1111/imb.12939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 06/17/2024] [Indexed: 07/02/2024]
Abstract
Transcriptomic data have been used to study sex chromosome dosage compensation (SCDC) in approximately 10 Lepidoptera ZW species, yielding a consensus compensation pattern of Z≈ ZZ < AA . $$ \approx \mathrm{ZZ}<\mathrm{AA}. $$ It remains unclear whether this compensation pattern holds when examining more Lepidoptera ZW species and/or using proteomic data to analyse SCDC. Here we combined transcriptomic and proteomic data as well as transcriptional level of six individual Z genes to reveal the SCDC pattern in Helicoverpa armigera, a polyphagous lepidopteran pest of economic importance. Transcriptomic analysis showed that the Z chromosome expression of H. armigera was balanced between male and female but substantially reduced relative to autosome expression, exhibiting an SCDC pattern of Z≈ ZZ < AA $$ \approx \mathrm{ZZ}<\mathrm{AA} $$ . When using H. amigera midgut proteomic data, the SCDC pattern of this species changed from Z≈ ZZ < AA $$ \approx \mathrm{ZZ}<\mathrm{AA} $$ at transcriptomic level to Z = ZZ = AA at the proteomic level. RT-qPCR analysis of transcript abundance of six Z genes found that compensation for each Z gene could vary from no compensation to overcompensation, depending on the individual genes and tissues tested. These results demonstrate for the first time the existence of a translational compensation mechanism, which is operating in addition to a translational mechanism, such as has been reported in other lepidopteran species. And the transcriptional compensation mechanism functions to accomplish Z chromosome dosage balance between the sexes (M = F on the Z chromosome), whereas the translation compensation mechanism operates to achieve dosage compensation between Z chromosome and autosome (Z = AA).
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Affiliation(s)
- Zhongyuan Deng
- School of Agricultural Sciences, Zhengzhou University, Zhengzhou, China
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yakun Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xingcheng Xie
- School of Agricultural Sciences, Zhengzhou University, Zhengzhou, China
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Huihui Li
- School of Life Sciences, Zhengzhou University, Zhengzhou, China
| | - Han Guo
- School of Life Sciences, Zhengzhou University, Zhengzhou, China
| | - Xinzhi Ni
- USDA-ARS, Crop Genetics and Breeding Research Unit, University of Georgia-Tifton Campus, Tifton, Georgia, USA
| | - Xianchun Li
- Department of Entomology and BIO5 Institute, University of Arizona, Tucson, Arizona, USA
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5
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Winge SB, Skakkebaek NE, Aksglaede L, Saritaş G, Rajpert-De Meyts E, Goossens E, Juul A, Almstrup K. X‑chromosome loss rescues Sertoli cell maturation and spermatogenesis in Klinefelter syndrome. Cell Death Dis 2024; 15:396. [PMID: 38839795 PMCID: PMC11153587 DOI: 10.1038/s41419-024-06792-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 05/22/2024] [Accepted: 05/29/2024] [Indexed: 06/07/2024]
Abstract
Klinefelter syndrome (47,XXY) causes infertility with a testicular histology comprising two types of Sertoli cell-only tubules, representing mature and immature-like Sertoli cells, and occasionally focal spermatogenesis. Here, we show that the immature-like Sertoli cells highly expressed XIST and had two X-chromosomes, while the mature Sertoli cells lacked XIST expression and had only one X-chromosome. Sertoli cells supporting focal spermatogenesis also lacked XIST expression and the additional X-chromosome, while the spermatogonia expressed XIST despite having only one X-chromosome. XIST was expressed in Sertoli cells until puberty, where a gradual loss was observed. Our results suggest that a micro-mosaic loss of the additional X-chromosome is needed for Sertoli cells to mature and to allow focal spermatogenesis.
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Affiliation(s)
- Sofia B Winge
- Department of Growth and Reproduction and the International Center for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health, Copenhagen, 2100, Denmark.
| | - Niels E Skakkebaek
- Department of Growth and Reproduction and the International Center for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health, Copenhagen, 2100, Denmark
| | - Lise Aksglaede
- Department of Growth and Reproduction and the International Center for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health, Copenhagen, 2100, Denmark
| | - Gülizar Saritaş
- Department of Growth and Reproduction and the International Center for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health, Copenhagen, 2100, Denmark
| | - Ewa Rajpert-De Meyts
- Department of Growth and Reproduction and the International Center for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health, Copenhagen, 2100, Denmark
| | - Ellen Goossens
- Research group Genetics, Reproduction and Development (GRAD), Biology of the Testis team, Vrije Universiteit Brussel, Brussels, 1090, Belgium
| | - Anders Juul
- Department of Growth and Reproduction and the International Center for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health, Copenhagen, 2100, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 2200, Denmark
| | - Kristian Almstrup
- Department of Growth and Reproduction and the International Center for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health, Copenhagen, 2100, Denmark.
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 2200, Denmark.
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6
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杨 晓. [Sperm Mosaic Variants and Their Influence on the Offspring]. SICHUAN DA XUE XUE BAO. YI XUE BAN = JOURNAL OF SICHUAN UNIVERSITY. MEDICAL SCIENCE EDITION 2024; 55:535-541. [PMID: 38948294 PMCID: PMC11211766 DOI: 10.12182/20240560507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Indexed: 07/02/2024]
Abstract
Genomic mosaicism arising from mosaic variants is a phenomenon that describes the presence of a cell or cell populations with different genome compositions from the germline cells of an individual. It comprises all types of genetic variants. A large proportion of childhood genetic disorders are defined as being de novo, meaning that the disease-causing mutations are only detected in the proband, not in any of the parents. Population studies show that 80% of the de novo mutations arise from the paternal haplotype, that is, from paternal sperm mosaicism. This review provides a summary of the types and detection strategies of sperm mosaicism. In addition, it provides discussions on how recent studies demonstrated that genomic mosaic mutations in parents, especially those in the paternal sperms, could be inherited by the offspring and cause childhood disorders. According to the previous findings of the author's research team, sperm mosaicism derived from early embryogenesis and primordial germ cell stages can explain 5% to 20% of the de novo mutations related to clinical phenotypes and can serve as an important predictor of both rare and complex disorders. Sperm mosaicism shows great potential for clinical genetic diagnosis and consultations. Based on the published literature, the author suggests that, large-scale screening for de novo sperm mosaic mutations and population-based genetic screening should be conducted in future studies, which will greatly enhance the risk assessment in the offspring and effectively improve the genetic health at the population level. Implementation of direct sperm detection for de novo mutations will significantly increase the efficiency of the stratification of patient cohorts and improve recurrence risk assessment for future births. Future research in the field should be focused on the impact of environmental and lifestyle factors on the health of the offspring through sperms and their modeling of mutation signatures. In addition, targeted in vitro modeling of sperm mutations will also be a promising direction.
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Affiliation(s)
- 晓旭 杨
- 犹他大学 (盐湖城 UT 84112)University of Utah, Salt Lake City, UT 84112, USA
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7
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Wilson CA, Postlethwait JH. A maternal-to-zygotic-transition gene block on the zebrafish sex chromosome. G3 (BETHESDA, MD.) 2024; 14:jkae050. [PMID: 38466753 PMCID: PMC11075544 DOI: 10.1093/g3journal/jkae050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 02/22/2024] [Accepted: 03/01/2024] [Indexed: 03/13/2024]
Abstract
Wild zebrafish (Danio rerio) have a ZZ/ZW chromosomal sex-determination system with the major sex locus on the right arm of chromosome-4 (Chr4R) near the largest heterochromatic block in the genome, suggesting that Chr4R transcriptomics might differ from the rest of the genome. To test this hypothesis, we conducted an RNA-seq analysis of adult ZW ovaries and ZZ testes in the Nadia strain and identified 4 regions of Chr4 with different gene expression profiles. Unique in the genome, protein-coding genes in a 41.7 Mb section (Region-2) were expressed in testis but silent in ovary. The AB lab strain, which lacks sex chromosomes, verified this result, showing that testis-biased gene expression in Region-2 depends on gonad biology, not on sex-determining mechanism. RNA-seq analyses in female and male brains and livers validated reduced transcripts from Region-2 in somatic cells, but without sex specificity. Region-2 corresponds to the heterochromatic portion of Chr4R and its content of genes and repetitive elements distinguishes it from the rest of the genome. Region-2 lacks protein-coding genes with human orthologs; has zinc finger genes expressed early in zygotic genome activation; has maternal 5S rRNA genes, maternal spliceosome genes, a concentration of tRNA genes, and a distinct set of repetitive elements. The colocalization of (1) genes silenced in ovaries but not in testes that are (2) expressed in embryos briefly at the onset of zygotic genome activation; (3) maternal-specific genes for translation machinery; (4) maternal-specific spliceosome components; and (5) adjacent genes encoding miR-430, which mediates maternal transcript degradation, suggest that this is a maternal-to-zygotic-transition gene regulatory block.
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8
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Wilson CA, Postlethwait JH. A maternal-to-zygotic-transition gene block on the zebrafish sex chromosome. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.06.570431. [PMID: 38106184 PMCID: PMC10723407 DOI: 10.1101/2023.12.06.570431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Wild zebrafish (Danio rerio) have a ZZ/ZW chromosomal sex determination system with the major sex locus on the right arm of chromosome-4 (Chr4R) near the largest heterochromatic block in the genome, suggesting the hypothesis that the Chr4R transcriptome might be different from the rest of the genome. We conducted an RNA-seq analysis of adult ZW ovaries and ZZ testes and identified four regions of Chr4 with different gene expression profiles. Unique in the genome, protein-coding genes in a 41.7 Mb section (Region-2) were expressed in testis but silent in ovary. The AB lab strain, which lacks sex chromosomes, verified this result, showing that testis-biased gene expression in Region-2 depends on gonad biology, not on sex-determining mechanism. RNA-seq analyses in female and male brain and liver validated few transcripts from Region-2 in somatic cells, but without sex-specificity. Region-2 corresponds to the heterochromatic portion of Chr4R and its content of genes and repetitive elements distinguishes it from the rest of the genome. In Region-2, protein-coding genes lack human orthologs; it has zinc finger genes expressed early in zygotic genome activation; it has maternal 5S rRNA genes, maternal spliceosome genes, a concentration of tRNA genes, and an distinct set of repetitive elements. The colocalization of 1) genes silenced in ovaries but not in testes that are 2) expressed in embryos briefly at the onset of zygotic genome activation; 3) maternal-specific genes for translation machinery; 4) maternal-specific spliceosome components; and 4) adjacent genes encoding miR-430, which mediates maternal transcript degradation, suggest that this is a Maternal-to-Zygotic-Transition Gene Regulatory Block.
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Kudo R, Yoshida I, Matiz Ceron L, Mizushima S, Kuroki Y, Jogahara T, Kuroiwa A. The Neo-X Does Not Form a Barr Body but Shows a Slightly Condensed Structure in the Okinawa Spiny Rat (Tokudaia muenninki). Cytogenet Genome Res 2023; 162:632-643. [PMID: 37271129 DOI: 10.1159/000531275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 05/27/2023] [Indexed: 06/06/2023] Open
Abstract
X chromosome inactivation (XCI) is an essential mechanism for gene dosage compensation between male and female cells in mammals. The Okinawa spiny rat (Tokudaia muenninki) is a native rodent in Japan with XX/XY sex chromosomes, like most mammals; however, the X chromosome has acquired a neo-X region (Xp) by fusion with an autosome. We previously reported that dosage compensation has not yet evolved in the neo-X region; however, X-inactive-specific transcript (Xist) RNA (long non-coding RNA required for the initiation of XCI) is partially localized in the region. Here, we show that the neo-X region represents an early chromosomal state in the acquisition of XCI by analyses of heterochromatin and Barr body formation. We found no evidence for heterochromatin formation in the neo-X region by R-banding by acridine orange (RBA) assays and immunostaining of H3K27me3. Double-immunostaining of H3K27me3 and HP1, a component of the Barr body, revealed that the entire ancestral X chromosome region (Xq) showed a bipartite folded structure. By contrast, HP1 was not localized to the neo-X region. However, BAC-FISH revealed that the signals of genes on the neo-X region of the inactive X chromosome were concentrated in a narrow region. These findings indicated that although the neo-X region of the inactive X chromosome does not form a complete Barr body structure (e.g., it lacks HP1), it forms a slightly condensed structure. These findings combined with the previously reported partial binding of Xist RNA suggest that the neo-X region exhibits incomplete inactivation. This may represent an early chromosomal state in the acquisition of the XCI mechanism.
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Affiliation(s)
- Ryoma Kudo
- Reproductive and Developmental Sciences, Biosystems Science Course, Graduate School of Life Science, Hokkaido University, Sapporo, Japan
| | - Ikuya Yoshida
- Reproductive and Developmental Sciences, Biosystems Science Course, Graduate School of Life Science, Hokkaido University, Sapporo, Japan
- Division of Reproductive and Developmental Biology, Department of Biological Sciences, Faculty of Science, Hokkaido University, Sapporo, Japan
| | - Luisa Matiz Ceron
- Reproductive and Developmental Sciences, Biosystems Science Course, Graduate School of Life Science, Hokkaido University, Sapporo, Japan
| | - Shusei Mizushima
- Reproductive and Developmental Sciences, Biosystems Science Course, Graduate School of Life Science, Hokkaido University, Sapporo, Japan
- Division of Reproductive and Developmental Biology, Department of Biological Sciences, Faculty of Science, Hokkaido University, Sapporo, Japan
| | - Yoko Kuroki
- Department of Genome Medicine, National Center for Child Health and Development, Tokyo, Japan
- Division of Collaborative Research, National Center for Child Health and Development, Tokyo, Japan
- Division of Diversity Research, National Research Institute for Child Health and Development, Tokyo, Japan
| | - Takamichi Jogahara
- Faculty of Law, Economics and Management, Okinawa University, Naha, Japan
| | - Asato Kuroiwa
- Reproductive and Developmental Sciences, Biosystems Science Course, Graduate School of Life Science, Hokkaido University, Sapporo, Japan
- Division of Reproductive and Developmental Biology, Department of Biological Sciences, Faculty of Science, Hokkaido University, Sapporo, Japan
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10
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Vargas LN, Silveira MM, Franco MM. Epigenetic Reprogramming and Somatic Cell Nuclear Transfer. Methods Mol Biol 2023; 2647:37-58. [PMID: 37041328 DOI: 10.1007/978-1-0716-3064-8_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/13/2023]
Abstract
Epigenetics is an area of genetics that studies the heritable modifications in gene expression and phenotype that are not controlled by the primary sequence of DNA. The main epigenetic mechanisms are DNA methylation, post-translational covalent modifications in histone tails, and non-coding RNAs. During mammalian development, there are two global waves of epigenetic reprogramming. The first one occurs during gametogenesis and the second one begins immediately after fertilization. Environmental factors such as exposure to pollutants, unbalanced nutrition, behavioral factors, stress, in vitro culture conditions can negatively affect epigenetic reprogramming events. In this review, we describe the main epigenetic mechanisms found during mammalian preimplantation development (e.g., genomic imprinting, X chromosome inactivation). Moreover, we discuss the detrimental effects of cloning by somatic cell nuclear transfer on the reprogramming of epigenetic patterns and some molecular alternatives to minimize these negative impacts.
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Affiliation(s)
- Luna N Vargas
- Laboratory of Animal Reproduction, Embrapa Genetic Resources and Biotechnology, Brasília, Distrito Federal, Brazil
- Institute of Biotechnology, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil
| | - Márcia M Silveira
- Laboratory of Animal Reproduction, Embrapa Genetic Resources and Biotechnology, Brasília, Distrito Federal, Brazil
- Institute of Biotechnology, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil
| | - Maurício M Franco
- Laboratory of Animal Reproduction, Embrapa Genetic Resources and Biotechnology, Brasília, Distrito Federal, Brazil.
- Institute of Biotechnology, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil.
- School of Veterinary Medicine, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil.
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11
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Tompkins JD. Discovering DNA Methylation, the History and Future of the Writing on DNA. JOURNAL OF THE HISTORY OF BIOLOGY 2022; 55:865-887. [PMID: 36239862 PMCID: PMC9941238 DOI: 10.1007/s10739-022-09691-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 09/05/2022] [Indexed: 06/16/2023]
Abstract
DNA methylation is a quintessential epigenetic mechanism. Widely considered a stable regulator of gene silencing, it represents a form of "molecular braille," chemically printed on DNA to regulate its structure and the expression of genetic information. However, there was a time when methyl groups simply existed in cells, mysteriously speckled across the cytosine building blocks of DNA. Why was the code of life chemically modified, apparently by "no accident of enzyme action" (Wyatt 1951)? If all cells in a body share the same genome sequence, how do they adopt unique functions and maintain stable developmental states? Do cells remember? In this historical perspective, I review epigenetic history and principles and the tools, key scientists, and concepts that brought us the synthesis and discovery of prokaryotic and eukaryotic methylated DNA. Drawing heavily on Gerard Wyatt's observation of asymmetric levels of methylated DNA across species, as well as to a pair of visionary 1975 DNA methylation papers, 5-methylcytosine is connected to DNA methylating enzymes in bacteria, the maintenance of stable cellular states over development, and to the regulation of gene expression through protein-DNA binding. These works have not only shaped our views on heritability and gene regulation but also remind us that core epigenetic concepts emerged from the intrinsic requirement for epigenetic mechanisms to exist. Driven by observations across prokaryotic and eukaryotic worlds, epigenetic systems function to access and interpret genetic information across all forms of life. Collectively, these works offer many guiding principles for our epigenetic understanding for today, and for the next generation of epigenetic inquiry in a postgenomics world.
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Affiliation(s)
- Joshua D Tompkins
- Arthur Riggs Diabetes Metabolism and Research Institute, City of Hope, 1500 E Duarte Road, Duarte, CA, 91010, USA.
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12
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Dosage Compensation in Drosophila: Its Canonical and Non-Canonical Mechanisms. Int J Mol Sci 2022; 23:ijms231810976. [PMID: 36142884 PMCID: PMC9506574 DOI: 10.3390/ijms231810976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 09/16/2022] [Accepted: 09/17/2022] [Indexed: 11/17/2022] Open
Abstract
Dosage compensation equalizes gene expression in a single male X chromosome with that in the pairs of autosomes and female X chromosomes. In the fruit fly Drosophila, canonical dosage compensation is implemented by the male-specific lethal (MSL) complex functioning in all male somatic cells. This complex contains acetyl transferase males absent on the first (MOF), which performs H4K16 hyperacetylation specifically in the male X chromosome, thus facilitating transcription of the X-linked genes. However, accumulating evidence points to an existence of additional, non-canonical dosage compensation mechanisms operating in somatic and germline cells. In this review, we discuss current advances in the understanding of both canonical and non-canonical mechanisms of dosage compensation in Drosophila.
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13
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Grimm NB, Lee JT. Selective Xi reactivation and alternative methods to restore MECP2 function in Rett syndrome. Trends Genet 2022; 38:920-943. [PMID: 35248405 PMCID: PMC9915138 DOI: 10.1016/j.tig.2022.01.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 01/15/2022] [Accepted: 01/19/2022] [Indexed: 10/19/2022]
Abstract
The human X-chromosome harbors only 4% of our genome but carries over 20% of genes associated with intellectual disability. Given that they inherit only one X-chromosome, males are more frequently affected by X-linked neurodevelopmental genetic disorders than females. However, despite inheriting two X-chromosomes, females can also be affected because X-chromosome inactivation enables only one of two X-chromosomes to be expressed per cell. For Rett syndrome and similar X-linked disorders affecting females, disease-specific treatments have remained elusive. However, a cure may be found within their own cells because every sick cell carries a healthy copy of the affected gene on the inactive X (Xi). Therefore, selective Xi reactivation may be a viable approach that would address the root cause of various X-linked disorders. Here, we discuss Rett syndrome and compare current approaches in the pharmaceutical pipeline to restore MECP2 function. We then focus on Xi reactivation and review available methods, lessons learned, and future directions.
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Affiliation(s)
- Niklas-Benedikt Grimm
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA; Department of Genetics, The Blavatnik Institute, Harvard Medical School, Boston, MA, USA; Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Jeannie T Lee
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA; Department of Genetics, The Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
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14
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Mattei AL, Bailly N, Meissner A. DNA methylation: a historical perspective. Trends Genet 2022; 38:676-707. [DOI: 10.1016/j.tig.2022.03.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/14/2022] [Accepted: 03/15/2022] [Indexed: 10/18/2022]
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15
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Thakur RK, Prasad P, Bhardwaj SC, Gangwar OP, Kumar S. Epigenetics of wheat-rust interaction: an update. PLANTA 2022; 255:50. [PMID: 35084577 DOI: 10.1007/s00425-022-03829-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 01/08/2022] [Indexed: 06/14/2023]
Abstract
The outcome of different host-pathogen interactions is influenced by both genetic and epigenetic systems, which determine the response of plants to pathogens and vice versa. This review highlights key molecular mechanisms and conceptual advances involved in epigenetic research and the progress made in epigenetics of wheat-rust interactions. Epigenetics implies the heritable changes in the way of gene expression as a consequence of the modification of DNA bases, histone proteins, and/or non-coding-RNA biogenesis without disturbing the underlying nucleotide sequence. The changes occurring between DNA and its surrounding chromatin without altering its DNA sequence and leading to significant changes in the genome of any organism are called epigenetic changes. Epigenetics has already been used successfully to explain the mechanism of human pathogens and in the identification of pathogen-induced modifications within various host plants. Wheat rusts are one of the most vital fungal diseases throughout the major wheat-growing areas of the world. The epigenome in plant pathogens causing diseases such as wheat rusts is mysterious. The investigations of host and pathogen epigenetics in the wheat rusts system can offer a piece of suitable evidence for elucidation of the molecular basis of host-pathogen interaction. Besides, the information on the epigenetic regulation of the genes involved in resistance or pathogenicity will provide better insights into the complex resistance signaling pathways and could provide answers to certain key questions, such as whether epigenetic regulation of certain genes is imparting resistance to host in response of certain pathogen elicitors or not. In the last few years, there has been an upsurge in research on the host as well as pathogen epigenetics and its outcome in plant-pathogen interactions. This review summarizes the progress made in the areas related to the epigenetic control of host-pathogen interaction with particular emphasis on wheat rusts.
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Affiliation(s)
- Rajni Kant Thakur
- ICAR-Indian Institute of Wheat and Barley Research, Regional Station, Shimla, Himachal Pradesh, 171002, India
| | - Pramod Prasad
- ICAR-Indian Institute of Wheat and Barley Research, Regional Station, Shimla, Himachal Pradesh, 171002, India.
| | - S C Bhardwaj
- ICAR-Indian Institute of Wheat and Barley Research, Regional Station, Shimla, Himachal Pradesh, 171002, India.
| | - O P Gangwar
- ICAR-Indian Institute of Wheat and Barley Research, Regional Station, Shimla, Himachal Pradesh, 171002, India
| | - Subodh Kumar
- ICAR-Indian Institute of Wheat and Barley Research, Regional Station, Shimla, Himachal Pradesh, 171002, India
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16
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Barreto VM, Kubasova N, Alves-Pereira CF, Gendrel AV. X-Chromosome Inactivation and Autosomal Random Monoallelic Expression as "Faux Amis". Front Cell Dev Biol 2021; 9:740937. [PMID: 34631717 PMCID: PMC8495168 DOI: 10.3389/fcell.2021.740937] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 08/30/2021] [Indexed: 12/23/2022] Open
Abstract
X-chromosome inactivation (XCI) and random monoallelic expression of autosomal genes (RMAE) are two paradigms of gene expression regulation where, at the single cell level, genes can be expressed from either the maternal or paternal alleles. X-chromosome inactivation takes place in female marsupial and placental mammals, while RMAE has been described in mammals and also other species. Although the outcome of both processes results in random monoallelic expression and mosaicism at the cellular level, there are many important differences. We provide here a brief sketch of the history behind the discovery of XCI and RMAE. Moreover, we review some of the distinctive features of these two phenomena, with respect to when in development they are established, their roles in dosage compensation and cellular phenotypic diversity, and the molecular mechanisms underlying their initiation and stability.
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Affiliation(s)
- Vasco M Barreto
- Chronic Diseases Research Centre, CEDOC, Nova Medical School, Lisbon, Portugal
| | - Nadiya Kubasova
- Chronic Diseases Research Centre, CEDOC, Nova Medical School, Lisbon, Portugal
| | - Clara F Alves-Pereira
- Department of Genetics, Smurfit Institute of Genetics, Trinity College Dublin, University of Dublin, Dublin, Ireland
| | - Anne-Valerie Gendrel
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
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17
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ArcRNAs and the formation of nuclear bodies. Mamm Genome 2021; 33:382-401. [PMID: 34085114 DOI: 10.1007/s00335-021-09881-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 05/25/2021] [Indexed: 01/13/2023]
Abstract
Long noncoding RNAs (lncRNAs) have long been collectively and passively defined as transcripts that do not encode proteins. However, extensive functional studies performed over the last decade have enabled the classification of lncRNAs into multiple categories according to their functions and/or molecular properties. Architectual RNAs (arcRNAs) are a group of lncRNAs that serve as architectural components of submicron-scale cellular bodies or nonmembranous organelles, which are composed of specific sets of proteins and nucleic acids involved in particular molecular processes. In this review, we focus on arcRNAs that function in the nucleus, which provide a structural basis for the formation of nuclear bodies, nonmembranous organelles in the cell nucleus. We will summarize the current list of arcRNAs and proteins associated with classic and more recently discovered nuclear bodies and discuss general rules that govern the formation of nuclear bodies, emphasizing weak multivalent interactions mediated by innately flexible biomolecules.
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18
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Choe HN, Jarvis ED. The role of sex chromosomes and sex hormones in vocal learning systems. Horm Behav 2021; 132:104978. [PMID: 33895570 DOI: 10.1016/j.yhbeh.2021.104978] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 03/22/2021] [Accepted: 03/23/2021] [Indexed: 12/12/2022]
Abstract
Vocal learning is the ability to imitate and modify sounds through auditory experience, a rare trait found in only a few lineages of mammals and birds. It is a critical component of human spoken language, allowing us to verbally transmit speech repertoires and knowledge across generations. In many vocal learning species, the vocal learning trait is sexually dimorphic, where it is either limited to males or present in both sexes to different degrees. In humans, recent findings have revealed subtle sexual dimorphism in vocal learning/spoken language brain regions and some associated disorders. For songbirds, where the neural mechanisms of vocal learning have been well studied, vocal learning appears to have been present in both sexes at the origin of the lineage and was then independently lost in females of some subsequent lineages. This loss is associated with an interplay between sex chromosomes and sex steroid hormones. Even in species with little dimorphism, like humans, sex chromosomes and hormones still have some influence on learned vocalizations. Here we present a brief synthesis of these studies, in the context of sex determination broadly, and identify areas of needed investigation to further understand how sex chromosomes and sex steroid hormones help establish sexually dimorphic neural structures for vocal learning.
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Affiliation(s)
- Ha Na Choe
- Duke University Medical Center, The Rockefeller University, Howard Hughes Medical Institute, United States of America.
| | - Erich D Jarvis
- Duke University Medical Center, The Rockefeller University, Howard Hughes Medical Institute, United States of America.
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19
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Sas-Nowosielska H, Magalska A. Long Noncoding RNAs-Crucial Players Organizing the Landscape of the Neuronal Nucleus. Int J Mol Sci 2021; 22:ijms22073478. [PMID: 33801737 PMCID: PMC8037058 DOI: 10.3390/ijms22073478] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 03/22/2021] [Accepted: 03/24/2021] [Indexed: 12/25/2022] Open
Abstract
The ability to regulate chromatin organization is particularly important in neurons, which dynamically respond to external stimuli. Accumulating evidence shows that lncRNAs play important architectural roles in organizing different nuclear domains like inactive chromosome X, splicing speckles, paraspeckles, and Gomafu nuclear bodies. LncRNAs are abundantly expressed in the nervous system where they may play important roles in compartmentalization of the cell nucleus. In this review we will describe the architectural role of lncRNAs in the nuclei of neuronal cells.
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20
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The Development of Epigenetics in the Study of Disease Pathogenesis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1253:57-94. [PMID: 32445091 DOI: 10.1007/978-981-15-3449-2_2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The study of epigenetics has its roots in the study of organism change over time and response to environmental change, although over the past several decades the definition has been formalized to include heritable alterations in gene expression that are not a result of alterations in underlying DNA sequence. In this chapter, we discuss first the history and milestones in the 100+ years of epigenetic study, including early discoveries of DNA methylation, histone posttranslational modification, and noncoding RNA. We then discuss how epigenetics has changed the way that we think of both health and disease, offering as examples studies examining the epigenetic contributions to aging, including the recent development of an epigenetic "clock", and explore how antiaging therapies may work through epigenetic modifications. We then discuss a nonpathogenic role for epigenetics in the clinic: epigenetic biomarkers. We conclude by offering two examples of modern state-of-the-art integrated multi-omics studies of epigenetics in disease pathogenesis, one which sought to capture shared mechanisms among multiple diseases, and another which used epigenetic big data to better understand the pathogenesis of a single tissue from one disease.
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21
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Veitia RA. AFF3: a new player in maintaining XIST monoallelic expression. J Mol Cell Biol 2019; 11:723-724. [PMID: 30629198 PMCID: PMC6821381 DOI: 10.1093/jmcb/mjy082] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 12/14/2018] [Indexed: 11/20/2022] Open
Affiliation(s)
- Reiner A Veitia
- Institut Jacques Monod, Université Paris Diderot, Paris, France.,Université Paris-Diderot, Paris, France
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22
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Wang C, Zhang S. Large-scale determination and characterization of cell type-specific regulatory elements in the human genome. J Mol Cell Biol 2019; 9:463-476. [PMID: 29281093 DOI: 10.1093/jmcb/mjx058] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 12/19/2017] [Indexed: 01/05/2023] Open
Abstract
Histone modifications have been widely elucidated to play vital roles in gene regulation and cell identity. The Roadmap Epigenomics Consortium generated a reference catalog of several key histone modifications across >100s of human cell types and tissues. Decoding these epigenomes into functional regulatory elements is a challenging task in computational biology. To this end, we adopted a differential chromatin modification analysis framework to comprehensively determine and characterize cell type-specific regulatory elements (CSREs) and their histone modification codes in the human epigenomes of five histone modifications across 127 tissues or cell types. The CSREs show significant relevance with cell type-specific biological functions and diseases and cell identity. Clustering of CSREs with their specificity signals reveals distinct histone codes, demonstrating the diversity of functional roles of CSREs within the same cell or tissue. Last but not least, dynamics of CSREs from close cell types or tissues can give a detailed view of developmental processes such as normal tissue development and cancer occurrence.
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Affiliation(s)
- Can Wang
- NCMIS, CEMS, RCSDS, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing 100190, China.,School of Mathematical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shihua Zhang
- NCMIS, CEMS, RCSDS, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing 100190, China.,School of Mathematical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
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23
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Liester MB, Sullivan EE. A review of epigenetics in human consciousness. COGENT PSYCHOLOGY 2019. [DOI: 10.1080/23311908.2019.1668222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Affiliation(s)
- Mitchell B. Liester
- Department of Psychiatry, University of Colorado School of Medicine, P.O. Box 302 153 N. Washington Street, Suite 103, Monument, CO 80132, USA
| | - Erin E. Sullivan
- Computer Science, University of Oklahoma, P.O. Box 302, Monument, CO 80132, USA
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24
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Duan JE, Shi W, Jue NK, Jiang Z, Kuo L, O'Neill R, Wolf E, Dong H, Zheng X, Chen J, Tian XC. Dosage Compensation of the X Chromosomes in Bovine Germline, Early Embryos, and Somatic Tissues. Genome Biol Evol 2019; 11:242-252. [PMID: 30566637 PMCID: PMC6354180 DOI: 10.1093/gbe/evy270] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/12/2018] [Indexed: 12/15/2022] Open
Abstract
Dosage compensation of the mammalian X chromosome (X) was proposed by Susumu Ohno as a mechanism wherein the inactivation of one X in females would lead to doubling the expression of the other. This would resolve the dosage imbalance between eutherian females (XX) versus male (XY) and between a single active X versus autosome pairs (A). Expression ratio of X- and A-linked genes has been relatively well studied in humans and mice, despite controversial results over the existence of upregulation of X-linked genes. Here we report the first comprehensive test of Ohno’s hypothesis in bovine preattachment embryos, germline, and somatic tissues. Overall an incomplete dosage compensation (0.5 < X:A < 1) of expressed genes and an excess X dosage compensation (X:A > 1) of ubiquitously expressed “dosage-sensitive” genes were seen. No significant differences in X:A ratios were observed between bovine female and male somatic tissues, further supporting Ohno’s hypothesis. Interestingly, preimplantation embryos manifested a unique pattern of X dosage compensation dynamics. Specifically, X dosage decreased after fertilization, indicating that the sperm brings in an inactive X to the matured oocyte. Subsequently, the activation of the bovine embryonic genome enhanced expression of X-linked genes and increased the X dosage. As a result, an excess compensation was exhibited from the 8-cell stage to the compact morula stage. The X dosage peaked at the 16-cell stage and stabilized after the blastocyst stage. Together, our findings confirm Ohno’s hypothesis of X dosage compensation in the bovine and extend it by showing incomplete and over-compensation for expressed and “dosage-sensitive” genes, respectively.
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Affiliation(s)
| | - Wei Shi
- Department of Statistics, University of Connecticut, Storrs, CT
| | - Nathaniel K Jue
- School of Natural Sciences, California State University, Monterey Bay, CA
| | - Zongliang Jiang
- School of Animal Science, Louisiana State University, Agricultural Center, Baton Rouge, LA
| | - Lynn Kuo
- Department of Statistics, University of Connecticut, Storrs, CT
| | - Rachel O'Neill
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT
| | - Eckhard Wolf
- Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität Muünchen, Germany
| | - Hong Dong
- Institute of Animal Science, Xinjiang Academy of Animal Sciences, Urumqi, Xinjiang, P.R. China
| | - Xinbao Zheng
- Institute of Animal Science, Xinjiang Academy of Animal Sciences, Urumqi, Xinjiang, P.R. China
| | - Jingbo Chen
- Institute of Animal Science, Xinjiang Academy of Animal Sciences, Urumqi, Xinjiang, P.R. China
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25
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Lemskaya NA, Kulemzina AI, Beklemisheva VR, Biltueva LS, Proskuryakova AA, Hallenbeck JM, Perelman PL, Graphodatsky AS. A combined banding method that allows the reliable identification of chromosomes as well as differentiation of AT- and GC-rich heterochromatin. Chromosome Res 2018; 26:307-315. [PMID: 30443803 DOI: 10.1007/s10577-018-9589-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 10/10/2018] [Accepted: 10/11/2018] [Indexed: 02/06/2023]
Abstract
Сonstitutive heterochromatin areas are revealed by differential staining as C-positive chromosomal regions. These C-positive bands may greatly vary by location, size, and nucleotide composition. CBG-banding is the most commonly used method to detect structural heterochromatin in animals. The difficulty in identification of individual chromosomes represents an unresolved problem of this method as the body of the chromosome is stained uniformly and does not have banding pattern beyond C-bands. Here, we present the method that we called CDAG for sequential heterochromatin staining after differential GTG-banding. The method uses G-banding followed by heat denaturation in the presence of formamide with consecutive fluorochrome staining. The new technique is valid for the concurrent revealing of heterochromatin position due to differential banding of chromosomes and heterochromatin composition (AT-/GC-rich) in animal karyotyping.
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Affiliation(s)
- Natalya A Lemskaya
- Institute of Molecular and Cellular Biology SB RAS, Novosibirsk, Russia.
| | | | | | - Larisa S Biltueva
- Institute of Molecular and Cellular Biology SB RAS, Novosibirsk, Russia
| | - Anastasia A Proskuryakova
- Institute of Molecular and Cellular Biology SB RAS, Novosibirsk, Russia
- Novosibirsk State University, Novosibirsk, Russia
| | - John M Hallenbeck
- Stroke Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health (NINDS/NIH), Bethesda, MD, USA
| | - Polina L Perelman
- Institute of Molecular and Cellular Biology SB RAS, Novosibirsk, Russia
- Novosibirsk State University, Novosibirsk, Russia
| | - Alexander S Graphodatsky
- Institute of Molecular and Cellular Biology SB RAS, Novosibirsk, Russia
- Novosibirsk State University, Novosibirsk, Russia
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26
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Galupa R, Heard E. X-Chromosome Inactivation: A Crossroads Between Chromosome Architecture and Gene Regulation. Annu Rev Genet 2018; 52:535-566. [PMID: 30256677 DOI: 10.1146/annurev-genet-120116-024611] [Citation(s) in RCA: 144] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In somatic nuclei of female therian mammals, the two X chromosomes display very different chromatin states: One X is typically euchromatic and transcriptionally active, and the other is mostly silent and forms a cytologically detectable heterochromatic structure termed the Barr body. These differences, which arise during female development as a result of X-chromosome inactivation (XCI), have been the focus of research for many decades. Initial approaches to define the structure of the inactive X chromosome (Xi) and its relationship to gene expression mainly involved microscopy-based approaches. More recently, with the advent of genomic techniques such as chromosome conformation capture, molecular details of the structure and expression of the Xi have been revealed. Here, we review our current knowledge of the 3D organization of the mammalian X-chromosome chromatin and discuss its relationship with gene activity in light of the initiation, spreading, and maintenance of XCI, as well as escape from gene silencing.
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Affiliation(s)
- Rafael Galupa
- Genetics and Developmental Biology Unit and Mammalian Developmental Epigenetics Group, Institut Curie, PSL Research University, CNRS UMR3215, INSERM U934, 75248 Paris, France; .,Current affiliation: Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Edith Heard
- Genetics and Developmental Biology Unit and Mammalian Developmental Epigenetics Group, Institut Curie, PSL Research University, CNRS UMR3215, INSERM U934, 75248 Paris, France; .,Collège de France, 75231 Paris, France
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27
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28
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Zhang H, Zhang Y, Wang YF, Morris D, Hirankarn N, Sheng Y, Shen J, Pan HF, Yang J, Yang S, Cui Y, Ye DQ, Vyse TJ, Zhang X, Lau YL, Yang W. Meta-analysis of GWAS on both Chinese and European populations identifies GPR173 as a novel X chromosome susceptibility gene for SLE. Arthritis Res Ther 2018; 20:92. [PMID: 29724251 PMCID: PMC5934841 DOI: 10.1186/s13075-018-1590-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 04/09/2018] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Systemic lupus erythematous (SLE) is a complex autoimmune disease with female predominance, particularly affecting those of childbearing age. We performed analysis of three genome-wide genotyping datasets of populations of both Chinese and European origin. METHODS This study involved 5695 cases and 10,357 controls in the discovery stage. The lead signal on chromosome X was followed by replication in three additional Asian cohorts, with 2300 cases and 4244 controls in total. Conditional analysis of the known associated loci on chromosome X was also performed to further explore independent signals. RESULTS Single-nucleotide polymorphism rs13440883 in GPR173 was found to be significantly associated with SLE (Pmeta = 7.53 × 10- 9, ORmeta= 1.16), whereas conditional analysis provided evidence of a potential independent signal in the L1CAM-IRAK1-MECP2 region in Asian populations (rs5987175 [LCA10]). CONCLUSIONS We identified a novel SLE susceptibility locus on the X chromosome. This finding emphasizes the importance of the X chromosome in disease pathogenesis and highlights the role of sex chromosomes in the female bias of SLE.
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Affiliation(s)
- Huoru Zhang
- Department of Paediatrics and Adolescent Medicine, Queen Mary Hospital, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Sandy Bay, Hong Kong
| | - Yan Zhang
- Department of Pediatric Surgery, Guangzhou Institute of Pediatrics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangdong, China.
| | - Yong-Fei Wang
- Department of Paediatrics and Adolescent Medicine, Queen Mary Hospital, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Sandy Bay, Hong Kong
| | - David Morris
- Division of Genetics and Molecular Medicine, King's College London, London, SE1 9RT, UK
| | - Nattiya Hirankarn
- Lupus Research Unit, Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Yujun Sheng
- Key Laboratory of Dermatology, Ministry of Education, Anhui Medical University, Hefei, Anhui, China
| | - Jiangshan Shen
- Department of Paediatrics and Adolescent Medicine, Queen Mary Hospital, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Sandy Bay, Hong Kong
| | - Hai-Feng Pan
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, Anhui, China
| | - Jing Yang
- Department of Paediatrics and Adolescent Medicine, Queen Mary Hospital, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Sandy Bay, Hong Kong
| | - Sen Yang
- Key Laboratory of Dermatology, Ministry of Education, Anhui Medical University, Hefei, Anhui, China
| | - Yong Cui
- Department of Dermatology, China-Japan Friendship Hospital, Beijing, China
| | - Dong-Qing Ye
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, Anhui, China
| | - Timothy J Vyse
- Division of Genetics and Molecular Medicine, King's College London, London, SE1 9RT, UK
| | - Xuejun Zhang
- Key Laboratory of Dermatology, Ministry of Education, Anhui Medical University, Hefei, Anhui, China
| | - Yu Lung Lau
- Department of Paediatrics and Adolescent Medicine, Queen Mary Hospital, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Sandy Bay, Hong Kong.
| | - Wanling Yang
- Department of Paediatrics and Adolescent Medicine, Queen Mary Hospital, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Sandy Bay, Hong Kong. .,Centre for Genomic Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Sandy Bay, Hong Kong.
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Stoll S, Wang C, Qiu H. DNA Methylation and Histone Modification in Hypertension. Int J Mol Sci 2018; 19:ijms19041174. [PMID: 29649151 PMCID: PMC5979462 DOI: 10.3390/ijms19041174] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Revised: 03/23/2018] [Accepted: 04/09/2018] [Indexed: 12/22/2022] Open
Abstract
Systemic hypertension, which eventually results in heart failure, renal failure or stroke, is a common chronic human disorder that particularly affects elders. Although many signaling pathways involved in the development of hypertension have been reported over the past decades, which has led to the implementation of a wide variety of anti-hypertensive therapies, one half of all hypertensive patients still do not have their blood pressure controlled. The frontier in understanding the molecular mechanisms underlying hypertension has now advanced to the level of epigenomics. Particularly, increasing evidence is emerging that DNA methylation and histone modifications play an important role in gene regulation and are involved in alteration of the phenotype and function of vascular cells in response to environmental stresses. This review seeks to highlight the recent advances in our knowledge of the epigenetic regulations and mechanisms of hypertension, focusing on the role of DNA methylation and histone modification in the vascular wall. A better understanding of the epigenomic regulation in the hypertensive vessel may lead to the identification of novel target molecules that, in turn, may lead to novel drug discoveries for the treatment of hypertension.
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Affiliation(s)
- Shaunrick Stoll
- Division of Pharmacology and Physiology, Department of Basic Sciences, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA.
| | - Charles Wang
- Center for Genomics, Department of Basic Sciences, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA.
| | - Hongyu Qiu
- Division of Pharmacology and Physiology, Department of Basic Sciences, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA.
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Dasmeh P. Multi-step regulation of transcription kinetics explains the non-linear relation between RNA polymerase II density and mRNA expression in dosage compensation. J Theor Biol 2018; 438:92-95. [PMID: 29162446 DOI: 10.1016/j.jtbi.2017.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 10/16/2017] [Accepted: 11/08/2017] [Indexed: 12/01/2022]
Abstract
In heterogametic organisms, expression of unequal number of X chromosomes in males and females is balanced by a process called dosage compensation. In Drosophila and mammals, dosage compensation involves nearly two-fold up-regulation of the X chromosome mediated by dosage compensation complex (DCC). Experimental studies on the role of DCC on RNA polymerase II (Pol II) transcription in mammals disclosed a non-linear relationship between Pol II densities at different transcription steps and mRNA expression. An ∼20-30% increase in Pol II densities corresponds to a rough 200% increase in mRNA expression and two-fold up-regulation. Here, using a simple kinetic model of Pol II transcription calibrated by in vivo measured rate constants of different transcription steps in mammalian cells, we demonstrate how this non-linearity can be explained by multi-step transcriptional regulation. Moreover, we show how multi-step enhancement of Pol II transcription can increase mRNA production while leaving Pol II densities unaffected. Our theoretical analysis not only recapitulates experimentally observed Pol II densities upon two-fold up-regulation but also points to erroneous interpretations of Pol II profiles from chromatin immunoprecipitation sequencing (ChIP-seq) or global run-on assays.
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Affiliation(s)
- Pouria Dasmeh
- Departement de Biochimie, Université de Montréal, 2900 Edouard-Montpetit, Montreal, Quebec H3T 1J4, Canada; Centre Robert Cedergren en Bioinformatique et Génomique, Université de Montréal, 2900 Edouard-Montpetit, Montreal, Quebec H3T 1J4, Canada; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02139, USA.
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31
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Saha P, Verma S, Pathak RU, Mishra RK. Long Noncoding RNAs in Mammalian Development and Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1008:155-198. [PMID: 28815540 DOI: 10.1007/978-981-10-5203-3_6] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Following analysis of sequenced genomes and transcriptome of many eukaryotes, it is evident that virtually all protein-coding genes have already been discovered. These advances have highlighted an intriguing paradox whereby the relative amount of protein-coding sequences remain constant but nonprotein-coding sequences increase consistently in parallel to increasing evolutionary complexity. It is established that differences between species map to nonprotein-coding regions of the genome that surprisingly is transcribed extensively. These transcripts regulate epigenetic processes and constitute an important layer of regulatory information essential for organismal development and play a causative role in diseases. The noncoding RNA-directed regulatory circuit controls complex characteristics. Sequence variations in noncoding RNAs influence evolution, quantitative traits, and disease susceptibility. This chapter presents an account on a class of such noncoding transcripts that are longer than 200 nucleotides (long noncoding RNA-lncRNA) in mammalian development and diseases.
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Affiliation(s)
- Parna Saha
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, 500007, India
| | - Shreekant Verma
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, 500007, India
| | - Rashmi U Pathak
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, 500007, India.
| | - Rakesh K Mishra
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, 500007, India.
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Abstract
The epigenome is a collection of chemical compounds that attach to and overlay the DNA sequence to direct gene expression. Epigenetic marks do not alter DNA sequence but instead allow or silence gene activity and the subsequent production of proteins that guide the growth and development of an organism, direct and maintain cell identity, and allow for the production of primordial germ cells (PGCs; ova and spermatozoa). The three main epigenetic marks are (1) histone modification, (2) DNA methylation, and (3) noncoding RNA, and each works in a different way to regulate gene expression. This article reviews these concepts and discusses their role in normal functions such as X-chromosome inactivation, epigenetic reprogramming during embryonic development and PGC production, and the clinical example of the imprinting disorders Angelman and Prader-Willi syndromes.
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Affiliation(s)
| | - Fay Wright
- Rory Meyers College of Nursing, New York, NY, USA
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Chatterjee RN. Dosage compensation and its roles in evolution of sex chromosomes and phenotypic dimorphism: lessons from Drosophila, C.elegans and mammals. THE NUCLEUS 2017. [DOI: 10.1007/s13237-017-0223-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
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Gu L, Walters JR, Knipple DC. Conserved Patterns of Sex Chromosome Dosage Compensation in the Lepidoptera (WZ/ZZ): Insights from a Moth Neo-Z Chromosome. Genome Biol Evol 2017; 9:802-816. [PMID: 28338816 PMCID: PMC5381563 DOI: 10.1093/gbe/evx039] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/01/2017] [Indexed: 02/07/2023] Open
Abstract
Where previously described, patterns of sex chromosome dosage compensation in the Lepidoptera (moths and butterflies) have several unusual characteristics. Other female-heterogametic (ZW/ZZ) species exhibit female Z-linked expression that is reduced compared with autosomal expression and male Z expression. In the Lepidoptera, however, Z expression typically appears balanced between sexes but overall reduced relative to autosomal expression, that is Z ≈ ZZ < AA. This pattern is not easily reconciled with theoretical expectations for the evolution of sex chromosome dosage compensation. Moreover, conflicting results linger due to discrepancies in data analyses and tissues sampled among lepidopterans. To address these issues, we performed RNA-seq to analyze sex chromosome dosage compensation in the codling moth, Cydia pomonella, which is a species from the earliest diverging lepidopteran lineage yet examined for dosage compensation and has a neo-Z chromosome resulting from an ancient Z:autosome fusion. While supported by intraspecific analyses, the Z ≈ ZZ < AA pattern was further evidenced by comparative study using autosomal orthologs of C. pomonella neo-Z genes in outgroup species. In contrast, dosage compensation appears to be absent in reproductive tissues. We thus argue that inclusion of reproductive tissues may explain the incongruence from a prior study on another moth species and that patterns of dosage compensation are likely conserved in the Lepidoptera. Notably, this pattern appears convergent with patterns in eutherian mammals (X ≈ XX < AA). Overall, our results contribute to the notion that the Lepidoptera present challenges both to classical theories regarding the evolution of sex chromosome dosage compensation and the emerging view of the association of dosage compensation with sexual heterogamety.
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Affiliation(s)
- Liuqi Gu
- Department of Entomology, Cornell University, Geneva, NY
| | - James R Walters
- Department of Ecology & Evolutionary Biology, The University of Kansas, Lawrence, KS
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35
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Stormo BM, Fox DT. Polyteny: still a giant player in chromosome research. Chromosome Res 2017; 25:201-214. [PMID: 28779272 PMCID: PMC5768140 DOI: 10.1007/s10577-017-9562-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 07/19/2017] [Accepted: 07/21/2017] [Indexed: 12/17/2022]
Abstract
In this era of high-resolution mapping of chromosome territories, topological interactions, and chromatin states, it is increasingly appreciated that the positioning of chromosomes and their interactions within the nucleus is critical for cellular function. Due to their large size and distinctive structure, polytene chromosomes have contributed a wealth of knowledge regarding chromosome regulation. In this review, we discuss the diversity of polytene chromosomes in nature and in disease, examine the recurring structural features of polytene chromosomes in terms of what they reveal about chromosome biology, and discuss recent advances regarding how polytene chromosomes are assembled and disassembled. After over 130 years of study, these giant chromosomes are still powerful tools to understand chromosome biology.
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Affiliation(s)
- Benjamin M Stormo
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Donald T Fox
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, 27710, USA.
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36
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Jin H, Park T, Won S. Efficient Statistical Method for Association Analysis of X-Linked Variants. Hum Hered 2017; 82:50-63. [PMID: 28810240 DOI: 10.1159/000478048] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 06/07/2017] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS Unlike the gene-poor Y chromosome, the X chromosome contains over 1,000 genes that are essential for viability of cells. Females have 2 X chromosomes, and thus female X-linked gene expression would be expected to be twice that of males. To adjust this imbalance, one of the 2 X-linked genes is often inactivated, and this is known as X-chromosome inactivation (XCI). However, recent studies described that a gene can be nonrandomly selected for inactivation from 2 X-linked genes and that XCI is not observed in some X-linked genes. Since this complex biological process has prevented efficient statistical association analyses, we propose a new statistical method against this uncertain biological process. METHODS The proposed method consists of 2 steps. First, p values for various biological processes are calculated and then combined into a single p value with the modified Fisher method and a minimum p value. RESULTS Our simulation results show that the proposed method is generally the most statistically efficient and is not sensitive to the unknown biological model. CONCLUSION Therefore, we can conclude that the proposed approaches are robust against the various XCI processes for testing the association of X-linked single nucleotide polymorphisms with the disease of interest and the proposed method is a practical solution.
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Affiliation(s)
- Heejin Jin
- Department of Public Health Science, Graduate School of Public Health, Seoul National University, Seoul, Korea
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37
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Dosage compensation in the process of inactivation/reactivation during both germ cell development and early embryogenesis in mouse. Sci Rep 2017. [PMID: 28623283 PMCID: PMC5473838 DOI: 10.1038/s41598-017-03829-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Ohno proposed that dosage compensation in mammals evolved as a two-step mechanism involving X-inactivation and X-upregulation. While X-inactivation is well characterized, it remains to further analysis whether upregulation of the single activated X chromosome in mammals occurs. We obtained RNA-seq data, including single-cell RNA-seq data, from cells undergoing inactivation/reactivation in both germ cell development and early embryogenesis stages in mouse and calculated the X: A ratio from the gene expression. Our results showed that the X: A ratio is always 1, regardless of the number of X chromosomes being transcribed for expressed genes. Furthermore, the single-cell RNA-seq data across individual cells of mouse preimplantation embryos of mixed backgrounds indicated that strain-specific SNPs could be used to distinguish transcription from maternal and paternal chromosomes and further showed that when the paternal was inactivated, the average gene dosage of the active maternal X chromosome was increased to restore the balance between the X chromosome and autosomes. In conclusion, our analysis of RNA-seq data (particularly single-cell RNA-seq) from cells undergoing the process of inactivation/reactivation provides direct evidence that the average gene dosage of the single active X chromosome is upregulated to achieve a similar level to that of two active X chromosomes and autosomes present in two copies.
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38
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Dosage Compensation in Drosophila-a Model for the Coordinate Regulation of Transcription. Genetics 2017; 204:435-450. [PMID: 27729494 DOI: 10.1534/genetics.115.185108] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 07/25/2016] [Indexed: 12/20/2022] Open
Abstract
The sex chromosomes have special significance in the history of genetics. The chromosomal basis of inheritance was firmly established when Calvin Bridges demonstrated that exceptions to Mendel's laws of segregation were accompanied at the cytological level by exceptional sex chromosome segregation. The morphological differences between X and Y exploited in Bridges' experiments arose as a consequence of the evolution of the sex chromosomes. Originally a homologous chromosome pair, the degeneration of the Y chromosome has been accompanied by a requirement for increased expression of the single X chromosome in males. Drosophila has been a model for the study of this dosage compensation and has brought key strengths, including classical genetics, the exceptional cytology of polytene chromosomes, and more recently, comprehensive genomics. The impact of these studies goes beyond sex chromosome regulation, providing valuable insights into mechanisms for the establishment and maintenance of chromatin domains, and for the coordinate regulation of transcription.
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39
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Yang T, Yildirim E. Epigenetic and LncRNA-Mediated Regulation of X Chromosome Inactivation and Its Impact on Pathogenesis. CURRENT PATHOBIOLOGY REPORTS 2017. [DOI: 10.1007/s40139-017-0120-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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41
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Vallot C, Ouimette JF, Rougeulle C. Establishment of X chromosome inactivation and epigenomic features of the inactive X depend on cellular contexts. Bioessays 2016; 38:869-80. [PMID: 27389958 DOI: 10.1002/bies.201600121] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
X chromosome inactivation (XCI) is an essential epigenetic process that ensures X-linked gene dosage equilibrium between sexes in mammals. XCI is dynamically regulated during development in a manner that is intimately linked to differentiation. Numerous studies, which we review here, have explored the dynamics of X inactivation and reactivation in the context of development, differentiation and diseases, and the phenotypic and molecular link between the inactive status, and the cellular context. Here, we also assess whether XCI is a uniform mechanism in mammals by analyzing epigenetic signatures of the inactive X (Xi) in different species and cellular contexts. It appears that the timing of XCI and the epigenetic signature of the inactive X greatly vary between species. Surprisingly, even within a given species, various Xi configurations are found across cellular states. We discuss possible mechanisms underlying these variations, and how they might influence the fate of the Xi.
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Affiliation(s)
- Céline Vallot
- Sorbonne Paris Cité, Epigenetics and Cell Fate, Université Paris Diderot, Paris, France
| | | | - Claire Rougeulle
- Sorbonne Paris Cité, Epigenetics and Cell Fate, Université Paris Diderot, Paris, France
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42
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Slager J, Veening JW. Hard-Wired Control of Bacterial Processes by Chromosomal Gene Location. Trends Microbiol 2016; 24:788-800. [PMID: 27364121 PMCID: PMC5034851 DOI: 10.1016/j.tim.2016.06.003] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 05/31/2016] [Accepted: 06/08/2016] [Indexed: 12/23/2022]
Abstract
Bacterial processes, such as stress responses and cell differentiation, are controlled at many different levels. While some factors, such as transcriptional regulation, are well appreciated, the importance of chromosomal gene location is often underestimated or even completely neglected. A combination of environmental parameters and the chromosomal location of a gene determine how many copies of its DNA are present at a given time during the cell cycle. Here, we review bacterial processes that rely, completely or partially, on the chromosomal location of involved genes and their fluctuating copy numbers. Special attention will be given to the several different ways in which these copy-number fluctuations can be used for bacterial cell fate determination or coordination of interdependent processes in a bacterial cell.
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Affiliation(s)
- Jelle Slager
- Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Jan-Willem Veening
- Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands.
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Pandya-Jones A, Plath K. The "lnc" between 3D chromatin structure and X chromosome inactivation. Semin Cell Dev Biol 2016; 56:35-47. [PMID: 27062886 DOI: 10.1016/j.semcdb.2016.04.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2016] [Revised: 04/01/2016] [Accepted: 04/04/2016] [Indexed: 12/01/2022]
Abstract
The long non-coding RNA Xist directs a remarkable instance of developmentally regulated, epigenetic change known as X Chromosome Inactivation (XCI). By spreading in cis across the X chromosome from which it is expressed, Xist RNA facilitates the creation of a heritably silent, heterochromatic nuclear territory that displays a three-dimensional structure distinct from that of the active X chromosome. How Xist RNA attaches to and propagates across a chromosome and its influence over the three-dimensional (3D) structure of the inactive X are aspects of XCI that have remained largely unclear. Here, we discuss studies that have made significant contributions towards answering these open questions.
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Affiliation(s)
- Amy Pandya-Jones
- Department of Biological Chemistry, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Kathrin Plath
- Department of Biological Chemistry, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA 90095, USA.
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44
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How Many Non-coding RNAs Does It Take to Compensate Male/Female Genetic Imbalance? ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 886:33-49. [PMID: 26659486 DOI: 10.1007/978-94-017-7417-8_3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Genetic sex determination in mammals relies on dimorphic sex chromosomes that confer phenotypic/physiologic differences between males and females. In this heterogametic system, X and Y chromosomes diverged from an ancestral pair of autosomes, creating a genetic disequilibrium between XX females and XY males. Dosage compensation mechanisms alleviate intrinsic gene dosage imbalance, leading to equal expression levels of most X-linked genes in the two sexes. In therian mammals, this is achieved through inactivation of one of the two X chromosomes in females. Failure to undergo X-chromosome inactivation (XCI) results in developmental arrest and death. Although fundamental for survival, a surprising loose conservation in the mechanisms to achieve XCI during development in therian lineage has been, and continues, to be uncovered. XCI involves the concerted action of non-coding RNAs (ncRNAs), including the well-known Xist RNA, and has thus become a classical paradigm to study the mode of action of this particular class of transcripts. In this chapter, we will describe the processes coping with sex chromosome genetic imbalance and how ncRNAs underlie dosage compensation mechanisms and influence male-female differences in mammals. Moreover, we will discuss how ncRNAs have been tinkered with during therian evolution to adapt XCI mechanistic to species-specific constraints.
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Gartler SM. Mary Lyon's X-inactivation studies in the mouse laid the foundation for the field of mammalian dosage compensation. J Genet 2015; 94:563-5. [PMID: 26690509 DOI: 10.1007/s12041-015-0575-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Stanley M Gartler
- Medicine (Medical Genetics), Genome Sciences and Pathology, University of Washington, 850 Republican St.,Seattle, WA 98109, USA.
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Ku CJ, Lim KC, Kalantry S, Maillard I, Engel JD, Hosoya T. A monoallelic-to-biallelic T-cell transcriptional switch regulates GATA3 abundance. Genes Dev 2015; 29:1930-41. [PMID: 26385963 PMCID: PMC4579350 DOI: 10.1101/gad.265025.115] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Ku et al. show that loss of one Gata3 allele leads to diminished expansion of immature T cells as well as aberrant induction of myeloid transcription factor PU.1. Gata3 is monoallelically expressed in hematopoietic stem cells and early T-cell progenitors. Half of the developing cells switch to biallelic Gata3 transcription abruptly at midthymopoiesis. Protein abundance must be precisely regulated throughout life, and nowhere is the stringency of this requirement more evident than during T-cell development: A twofold increase in the abundance of transcription factor GATA3 results in thymic lymphoma, while reduced GATA3 leads to diminished T-cell production. GATA3 haploinsufficiency also causes human HDR (hypoparathyroidism, deafness, and renal dysplasia) syndrome, often accompanied by immunodeficiency. Here we show that loss of one Gata3 allele leads to diminished expansion (and compromised development) of immature T cells as well as aberrant induction of myeloid transcription factor PU.1. This effect is at least in part mediated transcriptionally: We discovered that Gata3 is monoallelically expressed in a parent of origin-independent manner in hematopoietic stem cells and early T-cell progenitors. Curiously, half of the developing cells switch to biallelic Gata3 transcription abruptly at midthymopoiesis. We show that the monoallelic-to-biallelic transcriptional switch is stably maintained and therefore is not a stochastic phenomenon. This unique mechanism, if adopted by other regulatory genes, may provide new biological insights into the rather prevalent phenomenon of monoallelic expression of autosomal genes as well as into the variably penetrant pathophysiological spectrum of phenotypes observed in many human syndromes that are due to haploinsufficiency of the affected gene.
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Affiliation(s)
- Chia-Jui Ku
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA
| | - Kim-Chew Lim
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA
| | - Sundeep Kalantry
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA
| | - Ivan Maillard
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA; Division of Hematology-Oncology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA; Life Sciences Institute, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA
| | - James Douglas Engel
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA
| | - Tomonori Hosoya
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA
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Dixon-McDougall T, Brown C. The making of a Barr body: the mosaic of factors that eXIST on the mammalian inactive X chromosome. Biochem Cell Biol 2015; 94:56-70. [PMID: 26283003 DOI: 10.1139/bcb-2015-0016] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
During X-chromosome inactivation (XCI), nearly an entire X chromosome is permanently silenced and converted into a Barr body, providing dosage compensation for eutherians between the sexes. XCI is facilitated by the upregulation of the long non-coding RNA gene, XIST, which coats its chromosome of origin, recruits heterochromatin factors, and silences gene expression. During XCI, at least two distinct types of heterochromatin are established, and in this review we discuss the enrichment of facultative heterochromatin marks such as H3K27me3, H2AK119ub, and macroH2A as well as pericentric heterochromatin marks such as HP1, H3K9me3, and H4K20me3. The extremely stable maintenance of silencing is a product of reinforcing interactions within and between these domains. This paper "Xplores" the current knowledge of the pathways involved in XCI, how the pathways interact, and the gaps in our understanding that need to be filled.
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Affiliation(s)
- Thomas Dixon-McDougall
- Department of Medical Genetics, University of British Columbia, Vancouver, BC V6T 1Z3, Canada.,Department of Medical Genetics, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Carolyn Brown
- Department of Medical Genetics, University of British Columbia, Vancouver, BC V6T 1Z3, Canada.,Department of Medical Genetics, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
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Crowley JJ, Zhabotynsky V, Sun W, Huang S, Pakatci IK, Kim Y, Wang JR, Morgan AP, Calaway JD, Aylor DL, Yun Z, Bell TA, Buus RJ, Calaway ME, Didion JP, Gooch TJ, Hansen SD, Robinson NN, Shaw GD, Spence JS, Quackenbush CR, Barrick CJ, Nonneman RJ, Kim K, Xenakis J, Xie Y, Valdar W, Lenarcic AB, Wang W, Welsh CE, Fu CP, Zhang Z, Holt J, Guo Z, Threadgill DW, Tarantino LM, Miller DR, Zou F, McMillan L, Sullivan PF, Pardo-Manuel de Villena F. Analyses of allele-specific gene expression in highly divergent mouse crosses identifies pervasive allelic imbalance. Nat Genet 2015; 47:353-60. [PMID: 25730764 PMCID: PMC4380817 DOI: 10.1038/ng.3222] [Citation(s) in RCA: 162] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 01/26/2015] [Indexed: 12/15/2022]
Abstract
Complex human traits are influenced by variation in regulatory DNA through mechanisms that are not fully understood. Since regulatory elements are conserved between humans and mice, a thorough annotation of cis regulatory variants in mice could aid in this process. Here we provide a detailed portrait of mouse gene expression across multiple tissues in a three-way diallel. Greater than 80% of mouse genes have cis regulatory variation. These effects influence complex traits and usually extend to the human ortholog. Further, we estimate that at least one in every thousand SNPs creates a cis regulatory effect. We also observe two types of parent-of-origin effects, including classical imprinting and a novel, global allelic imbalance in favor of the paternal allele. We conclude that, as with humans, pervasive regulatory variation influences complex genetic traits in mice and provide a new resource toward understanding the genetic control of transcription in mammals.
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Affiliation(s)
- James J Crowley
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Vasyl Zhabotynsky
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Wei Sun
- 1] Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [2] Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Shunping Huang
- Department of Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Isa Kemal Pakatci
- Department of Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Yunjung Kim
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Jeremy R Wang
- Department of Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Andrew P Morgan
- 1] Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [2] Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [3] Carolina Center for Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - John D Calaway
- 1] Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [2] Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [3] Carolina Center for Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - David L Aylor
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Zaining Yun
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Timothy A Bell
- 1] Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [2] Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [3] Carolina Center for Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Ryan J Buus
- 1] Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [2] Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [3] Carolina Center for Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Mark E Calaway
- 1] Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [2] Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [3] Carolina Center for Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - John P Didion
- 1] Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [2] Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [3] Carolina Center for Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Terry J Gooch
- 1] Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [2] Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [3] Carolina Center for Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Stephanie D Hansen
- 1] Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [2] Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [3] Carolina Center for Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Nashiya N Robinson
- 1] Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [2] Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [3] Carolina Center for Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Ginger D Shaw
- 1] Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [2] Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [3] Carolina Center for Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Jason S Spence
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Corey R Quackenbush
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Cordelia J Barrick
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Randal J Nonneman
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Kyungsu Kim
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - James Xenakis
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Yuying Xie
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - William Valdar
- 1] Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [2] Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Alan B Lenarcic
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Wei Wang
- Department of Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Catherine E Welsh
- Department of Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Chen-Ping Fu
- Department of Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Zhaojun Zhang
- Department of Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - James Holt
- Department of Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Zhishan Guo
- Department of Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - David W Threadgill
- Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, Texas, USA
| | - Lisa M Tarantino
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Darla R Miller
- 1] Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [2] Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [3] Carolina Center for Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Fei Zou
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Leonard McMillan
- Department of Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Patrick F Sullivan
- 1] Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [2] Carolina Center for Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [3] Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [4] Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
| | - Fernando Pardo-Manuel de Villena
- 1] Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [2] Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [3] Carolina Center for Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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