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Innis SM, Cabot B. GBAF, a small BAF sub-complex with big implications: a systematic review. Epigenetics Chromatin 2020; 13:48. [PMID: 33143733 PMCID: PMC7607862 DOI: 10.1186/s13072-020-00370-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 10/23/2020] [Indexed: 12/01/2022] Open
Abstract
ATP-dependent chromatin remodeling by histone-modifying enzymes and chromatin remodeling complexes is crucial for maintaining chromatin organization and facilitating gene transcription. In the SWI/SNF family of ATP-dependent chromatin remodelers, distinct complexes such as BAF, PBAF, GBAF, esBAF and npBAF/nBAF are of particular interest regarding their implications in cellular differentiation and development, as well as in various diseases. The recently identified BAF subcomplex GBAF is no exception to this, and information is emerging linking this complex and its components to crucial events in mammalian development. Furthermore, given the essential nature of many of its subunits in maintaining effective chromatin remodeling function, it comes as no surprise that aberrant expression of GBAF complex components is associated with disease development, including neurodevelopmental disorders and numerous malignancies. It becomes clear that building upon our knowledge of GBAF and BAF complex function will be essential for advancements in both mammalian reproductive applications and the development of more effective therapeutic interventions and strategies. Here, we review the roles of the SWI/SNF chromatin remodeling subcomplex GBAF and its subunits in mammalian development and disease.
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Affiliation(s)
- Sarah M Innis
- Department of Animal Sciences, Purdue University, West Lafayette, IN, USA
| | - Birgit Cabot
- Department of Animal Sciences, Purdue University, West Lafayette, IN, USA.
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Characterization of the Importin-β binding domain in nuclear import receptor KPNA7. Biochem J 2020; 476:3413-3434. [PMID: 31642884 DOI: 10.1042/bcj20190717] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 10/22/2019] [Accepted: 10/23/2019] [Indexed: 12/19/2022]
Abstract
The KPNA family of mammalian nuclear import receptors are encoded by seven genes that generate isoforms with 42-86% identity. KPNA isoforms have the same protein architecture and share the functional property of nuclear localization signal (NLS) recognition, however, the tissue and developmental expression patterns of these receptors raise the question of whether subtle differences in KPNA isoforms might be important in specific biological contexts. Here, we show that KPNA7, an isoform with expression mostly limited to early development, can bind Importin-β (Imp-β) in the absence of NLS cargo. This result contrasts with Imp-β interactions with other KPNA family members, where affinity is regulated by NLS cargo as part of a cooperative binding mechanism. The Imp-β binding (IBB) domain, which is highly conserved in all KPNA family members, generally serves to occlude the NLS binding groove and maintain the receptor in an auto-inhibited 'closed' state prior to NLS contact. Cooperative binding of NLS cargo and Imp-β to KPNA results in an 'open'state. Characterization of KPNA2-KPNA7 chimeric proteins suggests that features of both the IBB domain and the core structure of the receptor contribute to the extent of IBB domain accessibility for Imp-β binding, which likely reflects an 'open' state. We also provide evidence that KPNA7 maintains an open-state in the nucleus. We speculate that KPNA7 could function within the nucleus by interacting with NLS-containing proteins.
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Heim A, Rymarczyk B, Mayer TU. Regulation of Cell Division. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 953:83-116. [PMID: 27975271 DOI: 10.1007/978-3-319-46095-6_3] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The challenging task of mitotic cell divisions is to generate two genetically identical daughter cells from a single precursor cell. To accomplish this task, a complex regulatory network evolved, which ensures that all events critical for the duplication of cellular contents and their subsequent segregation occur in the correct order, at specific intervals and with the highest possible fidelity. Transitions between cell cycle stages are triggered by changes in the phosphorylation state and levels of components of the cell cycle machinery. Entry into S-phase and M-phase are mediated by cyclin-dependent kinases (Cdks), serine-threonine kinases that require a regulatory cyclin subunit for their activity. Resetting the system to the interphase state is mediated by protein phosphatases (PPs) that counteract Cdks by dephosphorylating their substrates. To avoid futile cycles of phosphorylation and dephosphorylation, Cdks and PPs must be regulated in a manner such that their activities are mutually exclusive.
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Affiliation(s)
- Andreas Heim
- Department of Biology and Konstanz Research School Chemical Biology (KoRS-CB), University of Konstanz, Universitätsstr. 10, 78457, Konstanz, Germany
| | - Beata Rymarczyk
- Department of Biology and Konstanz Research School Chemical Biology (KoRS-CB), University of Konstanz, Universitätsstr. 10, 78457, Konstanz, Germany
| | - Thomas U Mayer
- Department of Biology and Konstanz Research School Chemical Biology (KoRS-CB), University of Konstanz, Universitätsstr. 10, 78457, Konstanz, Germany.
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Cloning and characterization of ifitm1 and ifitm3 expression during early zebrafish development. ZYGOTE 2015; 24:149-58. [PMID: 25613417 DOI: 10.1017/s0967199414000756] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The family of interferon-inducible transmembrane proteins (IFITMs) plays a crucial role in inhibiting proliferation, promoting homotypic cell adhesion and mediating germ cell development. In the present study, the full-length cDNAs of zebrafish ifitm1 (744 bp) and ifitm3 (702 bp) were obtained by rapid amplification of cDNA ends (RACE). Reverse transcription polymerase chain reaction (RT-PCR) analysis showed that ifitm1 mRNA was expressed in the ovary, testis, brain, muscle, liver and kidney, while ifitm3 mRNA was only detected in the ovary. Based on in situ hybridization, ifitm1 mRNA was found to be strongly expressed in the ooplasm from stage I to stage II and ifitm3 mRNA was also strongly expressed in the ooplasm from stage I to stage II, furthermore ifitm3 expression ultimately localized to the cortex region beneath the plasma membrane of stage IV oocytes. During development, ifitm1 expression was initially detected in the enveloping layer cells and deep layer cells of shield stage embryos. Then, throughout the segmentation phase (10.25-24 hours post-fertilization (hpf)), ifitm1 expression was mainly detected in the head, trunk and tail regions. Unlike ifitm1, ifitm3 expression was initially detected in sphere stage embryos and was then broadly expressed throughout the embryo from the 70% epiboly stage to 24 hpf. Interestingly, ifitm3 was also expressed in primordial germ cells (PGCs) from the bud stage to 24 hpf. This expression analysis indicates that zebrafish ifitm1 may play a critical role in early organogenesis and may perform immune or hematopoietic functions and ifitm3 might be necessary for PGC migration and the formation of female germ cells.
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Zahmatkesh A, Ansari Mahyari S, Daliri Joupari M, Shirazi A, Rahmani H. Expression of bovine Ecat1 gene in immature and in vitro matured oocytes as well as during early embryonic development. Reprod Domest Anim 2014; 50:34-40. [PMID: 25366560 DOI: 10.1111/rda.12446] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 09/21/2014] [Indexed: 12/13/2022]
Abstract
Ecat1 is a maternal effect gene that is exclusively expressed in oocytes and embryonic stem cells, and has an important role in pre-implantation development. This study was designed to investigate the expression of bovine Ecat1 gene in immature and in vitro matured oocytes as well as during early embryonic development, and also Ecat1 protein localization. Samples were obtained from slaughtered animals. RNA extractions were carried out from ovary, immature and in vitro matured oocytes and also different stages of embryonic development (2-, 4-, 8- to 16-cell stages and blastocysts). RT-PCR analysis revealed the expression of Ecat1 in ovary, oocytes and embryos. Analysis in FGENESH online tool predicted three exons and one transcription start site (TSS) in Ecat1 gene, and the 3' RACE-PCR result showed that just one splice variant was amplified. By quantitative real-time PCR technique, we showed that Ecat1 transcript increased at 8- to 16-cell-stage embryos and decreased in blastocyst stage (p < 0.05). Immunofluorescence analysis showed cytoplasmic localization of Ecat1 protein in bovine oocytes. Results demonstrated bovine Ecat1 expression at protein level and also indicated that Ecat1 has a significant higher embryonic expression at 8- to 16-cell stage. This embryonic expression is probably required for further developmental stages.
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Affiliation(s)
- A Zahmatkesh
- Department of Animal Sciences, College of Agriculture, Isfahan University of Technology, Isfahan, Iran
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Meglicki M, Teperek-Tkacz M, Borsuk E. Appearance and heterochromatin localization of HP1α in early mouse embryos depends on cytoplasmic clock and H3S10 phosphorylation. Cell Cycle 2014; 11:2189-205. [DOI: 10.4161/cc.20705] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Nuclear distribution of RNA polymerase II and mRNA processing machinery in early mammalian embryos. BIOMED RESEARCH INTERNATIONAL 2014; 2014:681596. [PMID: 24868542 PMCID: PMC4020508 DOI: 10.1155/2014/681596] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 04/11/2014] [Indexed: 11/17/2022]
Abstract
Spatial distribution of components of nuclear metabolism provides a significant impact on regulation of the processes of gene expression. While distribution of the key nuclear antigens and their association with the defined nuclear domains were thoroughly traced in mammalian somatic cells, similar data for the preimplantation embryos are scanty and fragmental. However, the period of cleavage is characterized by the most drastic and dynamic nuclear reorganizations accompanying zygotic gene activation. In this minireview, we try to summarize the results of studies concerning distribution of major factors involved in RNA polymerase II-dependent transcription, pre-mRNA splicing mRNA export that have been carried out on early embryos of mammals.
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Li L, Lu X, Dean J. The maternal to zygotic transition in mammals. Mol Aspects Med 2013; 34:919-38. [PMID: 23352575 DOI: 10.1016/j.mam.2013.01.003] [Citation(s) in RCA: 154] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 01/08/2013] [Accepted: 01/11/2013] [Indexed: 11/15/2022]
Abstract
Prior to activation of the embryonic genome, the initiating events of mammalian development are under maternal control and include fertilization, the block to polyspermy and processing sperm DNA. Following gamete union, the transcriptionally inert sperm DNA is repackaged into the male pronucleus which fuses with the female pronucleus to form a 1-cell zygote. Embryonic transcription begins during the maternal to zygotic transfer of control in directing development. This transition occurs at species-specific times after one or several rounds of blastomere cleavage and is essential for normal development. However, even after activation of the embryonic genome, successful development relies on stored maternal components without which embryos fail to progress beyond initial cell divisions. Better understanding of the molecular basis of maternal to zygotic transition including fertilization, the activation of the embryonic genome and cleavage-stage development will provide insight into early human development that should translate into clinical applications for regenerative medicine and assisted reproductive technologies.
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Affiliation(s)
- Lei Li
- Division of Molecular Embryonic Development, State Key Laboratory of Reproductive Biology, Institute of Zoology/Chinese Academy of Sciences, Beijing 100101, PR China.
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Verma A, Kumar P, Rajput S, Roy B, De S, Datta T. Embryonic genome activation events in buffalo (Bubalus bubalis) preimplantation embryos. Mol Reprod Dev 2012; 79:321-8. [DOI: 10.1002/mrd.22027] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Accepted: 01/25/2012] [Indexed: 11/11/2022]
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Abstract
Mammalian preimplantation development is a process of dedifferentiation from the terminally differentiated eggs to the totipotent blastomeres at the cleavage stage, and then to the pluripotent cells at the blastocyst stage. Maternal factors that accumulate during oogenesis dominate early preimplantation development until the embryonic factors gain control after the activation of the embryonic genome. Recently, a handful of maternal factors that are encoded by the maternal-effect genes have been characterized in genetically modified mouse models. These factors are shown to participate in many aspects of preimplantation development, such as the degradation of maternal macromolecues, epigenetic modification, protein translation, cellular signaling transduction, and cell compaction. Even so, little is known about the interactions between different maternal factors. In this chapter, we have summarized the functions of known maternal factors and hopefully this will lead to a better understanding of the regulation of preimplantation embryogenesis by the maternal regulatory network.
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Affiliation(s)
- Wenjing Zheng
- Department of Cell and Molecular Biology, University of Gothenburg, Gothenburg, Sweden.
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Mouse and human pluripotent stem cells and the means of their myogenic differentiation. Results Probl Cell Differ 2012; 55:321-56. [PMID: 22918815 DOI: 10.1007/978-3-642-30406-4_18] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Pluripotent stem cells, such as embryonic stem cells and induced pluripotent stem cells, are an important tool in the studies focusing at the differentiation of various cell types, including skeletal myoblasts. They are also considered as a source of the cells that due to their pluripotent character and availability could be turned into any required tissue and then used in future in regenerative medicine. However, the methods of the derivation of some of cell types from pluripotent cells still need to be perfected. This chapter summarizes the history and current advancements in the derivation and testing of pluripotent stem cells-derived skeletal myoblasts. It focuses at the in vitro methods allowing the differentiation of stem cells grown in monolayer or propagated as embryoid bodies, and also at in vivo tests allowing the verification of the functionality of obtained skeletal myoblasts.
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Andreu-Vieyra CV, Chen R, Agno JE, Glaser S, Anastassiadis K, Stewart AF, Matzuk MM. MLL2 is required in oocytes for bulk histone 3 lysine 4 trimethylation and transcriptional silencing. PLoS Biol 2010; 8. [PMID: 20808952 PMCID: PMC2923083 DOI: 10.1371/journal.pbio.1000453] [Citation(s) in RCA: 188] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Accepted: 07/02/2010] [Indexed: 11/19/2022] Open
Abstract
Conditional knockout mouse strategies identify the histone methyltranferase MLL2 as a key player in epigenetic reprogramming of female gametes. During gametogenesis and pre-implantation development, the mammalian epigenome is reprogrammed to establish pluripotency in the epiblast. Here we show that the histone 3 lysine 4 (H3K4) methyltransferase, MLL2, controls most of the promoter-specific chromatin modification, H3K4me3, during oogenesis and early development. Using conditional knockout mutagenesis and a hypomorph model, we show that Mll2 deficiency in oocytes results in anovulation and oocyte death, with increased transcription of p53, apoptotic factors, and Iap elements. MLL2 is required for (1) bulk H3K4me3 but not H3K4me1, indicating that MLL2 controls most promoters but monomethylation is regulated by a different H3K4 methyltransferase; (2) the global transcriptional silencing that preceeds resumption of meiosis but not for the concomitant nuclear reorganization into the surrounded nucleolus (SN) chromatin configuration; (3) oocyte survival; and (4) normal zygotic genome activation. These results reveal that MLL2 is autonomously required in oocytes for fertility and imply that MLL2 contributes to the epigenetic reprogramming that takes place before fertilization. We propose that once this task has been accomplished, MLL2 is not required until gastrulation and that other methyltransferases are responsible for bulk H3K4me3, thereby revealing an unexpected epigenetic control switch amongst the H3K4 methyltransferases during development. It is well established that gametes and early mammalian embryos undergo extensive epigenetic changes, which are changes in phenotype or gene expression that do not entail changes in DNA sequence. However, the machinery responsible for epigenetic modification in these situations is poorly understood. In mice, we conditionally deleted the histone 3 lysine 4 (H3K4) methyltransferase Mll2, an enzyme that alters DNA structure and packaging, either in gametes or in somatic cells of the ovary and also produced a mouse hypomorph expressing low levels of MLL2. We show that MLL2 is required in oocytes during gametogenesis and is also needed as a maternally derived factor during early development. Oocytes deficient in Mll2 display decreased methylation of H3K4 (H3K4me3) and show abnormal maturation and gene expression, in particular of pro-apoptotic factors. In addition, we demonstrate that embryonic genome activation is compromised in the absence of Mll2. Together our results identify MLL2 as one of the key players in the epigenetic reprogramming required for female fertility in the mouse.
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Affiliation(s)
- Claudia V. Andreu-Vieyra
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Ruihong Chen
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Julio E. Agno
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Stefan Glaser
- Genomics, BioInnovationsZentrum, Technische Universitaet Dresden, Dresden, Germany
- Walter and Eliza Hall Institute, Melbourne, Australia
| | | | - A. Francis Stewart
- Genomics, BioInnovationsZentrum, Technische Universitaet Dresden, Dresden, Germany
- * E-mail: (MMM); (AFS)
| | - Martin M. Matzuk
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail: (MMM); (AFS)
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Yamada M, Hamatani T, Akutsu H, Chikazawa N, Kuji N, Yoshimura Y, Umezawa A. Involvement of a novel preimplantation-specific gene encoding the high mobility group box protein Hmgpi in early embryonic development. Hum Mol Genet 2010; 19:480-93. [PMID: 19915186 PMCID: PMC2798723 DOI: 10.1093/hmg/ddp512] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2009] [Revised: 10/22/2009] [Accepted: 11/11/2009] [Indexed: 11/13/2022] Open
Abstract
Mining gene-expression-profiling data identified a novel gene that is specifically expressed in preimplantation embryos. Hmgpi, a putative chromosomal protein with two high-mobility-group boxes, is zygotically transcribed during zygotic genome activation, but is not transcribed postimplantation. The Hmgpi-encoded protein (HMGPI), first detected at the 4-cell stage, remains highly expressed in pre-implantation embryos. Interestingly, HMGPI is expressed in both the inner cell mass (ICM) and the trophectoderm, and translocated from cytoplasm to nuclei at the blastocyst stage, indicating differential spatial requirements before and after the blastocyst stage. siRNA (siHmgpi)-induced reduction of Hmgpi transcript levels caused developmental loss of preimplantation embryos and implantation failures. Furthermore, reduction of Hmgpi prevented blastocyst outgrowth leading to generation of embryonic stem cells. The siHmgpi-injected embryos also lost ICM and trophectoderm integrity, demarcated by reduced expressions of Oct4, Nanog and Cdx2. The findings implicated an important role for Hmgpi at the earliest stages of mammalian embryonic development.
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Affiliation(s)
- Mitsutoshi Yamada
- Department of Obstetrics and Gynecology, Keio University School of Medicine, 35 Shinanomachi Shinjyuku-ku, Tokyo 160-8582, Japan and
- Department of Reproductive Biology, National Research Institute for Child Health and Development, 2-10-1 Ohkura Setagaya-ku, Tokyo 157-8535, Japan
| | - Toshio Hamatani
- Department of Obstetrics and Gynecology, Keio University School of Medicine, 35 Shinanomachi Shinjyuku-ku, Tokyo 160-8582, Japan and
| | - Hidenori Akutsu
- Department of Reproductive Biology, National Research Institute for Child Health and Development, 2-10-1 Ohkura Setagaya-ku, Tokyo 157-8535, Japan
| | - Nana Chikazawa
- Department of Obstetrics and Gynecology, Keio University School of Medicine, 35 Shinanomachi Shinjyuku-ku, Tokyo 160-8582, Japan and
- Department of Reproductive Biology, National Research Institute for Child Health and Development, 2-10-1 Ohkura Setagaya-ku, Tokyo 157-8535, Japan
| | - Naoaki Kuji
- Department of Obstetrics and Gynecology, Keio University School of Medicine, 35 Shinanomachi Shinjyuku-ku, Tokyo 160-8582, Japan and
| | - Yasunori Yoshimura
- Department of Obstetrics and Gynecology, Keio University School of Medicine, 35 Shinanomachi Shinjyuku-ku, Tokyo 160-8582, Japan and
| | - Akihiro Umezawa
- Department of Reproductive Biology, National Research Institute for Child Health and Development, 2-10-1 Ohkura Setagaya-ku, Tokyo 157-8535, Japan
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Oestrup O, Hall V, Petkov SG, Wolf XA, Hyldig S, Hyttel P. From Zygote to Implantation: Morphological and Molecular Dynamics during Embryo Development in the Pig. Reprod Domest Anim 2009; 44 Suppl 3:39-49. [DOI: 10.1111/j.1439-0531.2009.01482.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Xu Y, Lei Y, Liu Q, Liu Y, Liu S, Cheng H, Deng F. Cloning, characterization and expression ofzvep, a novel vitelline envelope-specific gene in the zebrafish ovary. Mol Reprod Dev 2009; 76:593-600. [DOI: 10.1002/mrd.20985] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Uzun A, Rodriguez-Osorio N, Kaya A, Wang H, Parrish JJ, Ilyin VA, Memili E. Functional genomics of HMGN3a and SMARCAL1 in early mammalian embryogenesis. BMC Genomics 2009; 10:183. [PMID: 19393058 PMCID: PMC2684548 DOI: 10.1186/1471-2164-10-183] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Accepted: 04/24/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Embryonic genome activation (EGA) is a critical event for the preimplantation embryo, which is manifested by changes in chromatin structure, transcriptional machinery, expression of embryonic genes, and degradation of maternal transcripts. The objectives of this study were to determine transcript abundance of HMGN3a and SMARCAL1 in mature bovine oocytes and early bovine embryos, to perform comparative functional genomics analysis of these genes across mammals. RESULTS New annotations of both HMGN3a and SMARCAL1 were submitted to the Bovine Genome Annotation Submission Database at BovineGenome.org. Careful analysis of the bovine SMARCAL1 consensus gene set for this protein (GLEAN_20241) showed that the NCBI protein contains sequencing errors, and that the actual bovine protein has a high degree of homology to the human protein. Our results showed that there was a high degree of structural conservation of HMGN3a and SMARCAL1 in the mammalian species studied. HMGN3a transcripts were present at similar levels in bovine matured oocytes and 2-4-cell embryos but at higher levels in 8-16-cell embryos, morulae and blastocysts. On the other hand, transcript levels of SMARCAL1 decreased throughout preimplantation development. CONCLUSION The high levels of structural conservation of these proteins highlight the importance of chromatin remodeling in the regulation of gene expression, particularly during early mammalian embryonic development. The greater similarities of human and bovine HMGN3a and SMARCAL1 proteins may suggest the cow as a valuable model to study chromatin remodeling at the onset of mammalian development. Understanding the roles of chromatin remodeling proteins during embryonic development emphasizes the importance of epigenetics and could shed light on the underlying mechanisms of early mammalian development.
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Affiliation(s)
- Alper Uzun
- Department of Biology, Northeastern University, Boston, MA, USA.
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George RP, Lee P. Embryonic human persons. Talking Point on morality and human embryo research. EMBO Rep 2009; 10:301-6. [PMID: 19337298 PMCID: PMC2672893 DOI: 10.1038/embor.2009.42] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Genome-wide expression profiling reveals distinct clusters of transcriptional regulation during bovine preimplantation development in vivo. Proc Natl Acad Sci U S A 2008; 105:19768-73. [PMID: 19064908 DOI: 10.1073/pnas.0805616105] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bovine embryos can be generated by in vitro fertilization or somatic nuclear transfer; however, these differ from their in vivo counterparts in many aspects and exhibit a higher proportion of developmental abnormalities. Here, we determined for the first time the transcriptomes of bovine metaphase II oocytes and all stages of preimplantation embryos developing in vivo up to the blastocyst using the Affymetrix GeneChip Bovine Genome Array which examines approximately 23,000 transcripts. The data show that bovine oocytes and embryos transcribed a significantly higher number of genes than somatic cells. Several hundred genes were transcribed well before the 8-cell stage, at which the major activation of the bovine genome expression occurs. Importantly, stage-specific expression patterns in 2-cell, 4-cell, and 8-cell stages, and in morulae and blastocysts, were detected, indicating dynamic changes in the embryonic transcriptome and in groups of transiently active genes. Pathway analysis revealed >120 biochemical pathways that are operative in early preimplantation bovine development. Significant differences were observed between the mRNA expression profiles of in vivo and in vitro matured oocytes, highlighting the need to include in vivo derived oocytes/embryos in studies evaluating assisted reproductive techniques. This study provides the first comprehensive analysis of gene expression and transcriptome dynamics of in vivo developing bovine embryos and will serve as a basis for improving assisted reproductive technology.
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Ko M, Sohn DH, Chung H, Seong RH. Chromatin remodeling, development and disease. Mutat Res 2008; 647:59-67. [PMID: 18786551 DOI: 10.1016/j.mrfmmm.2008.08.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2008] [Revised: 07/30/2008] [Accepted: 08/07/2008] [Indexed: 05/26/2023]
Abstract
Development is a stepwise process in which multi-potent progenitor cells undergo lineage commitment, differentiation, proliferation and maturation to produce mature cells with restricted developmental potentials. This process is directed by spatiotemporally distinct gene expression programs that allow cells to stringently orchestrate intricate transcriptional activation or silencing events. In eukaryotes, chromatin structure contributes to developmental progression as a blueprint for coordinated gene expression by actively participating in the regulation of gene expression. Changes in higher order chromatin structure or covalent modification of its components are considered to be critical events in dictating lineage-specific gene expression during development. Mammalian cells utilize multi-subunit nuclear complexes to alter chromatin structure. Histone-modifying complex catalyzes covalent modifications of histone tails including acetylation, methylation, phosphorylation and ubiquitination. ATP-dependent chromatin remodeling complex, which disrupts histone-DNA contacts and induces nucleosome mobilization, requires energy from ATP hydrolysis for its catalytic activity. Here, we discuss the diverse functions of ATP-dependent chromatin remodeling complexes during mammalian development. In particular, the roles of these complexes during embryonic and hematopoietic development are reviewed in depth. In addition, pathological conditions such as tumor development that are induced by mutation of several key subunits of the chromatin remodeling complex are discussed, together with possible mechanisms that underlie tumor suppression by the complex.
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Affiliation(s)
- Myunggon Ko
- Department of Biological Sciences, Institute of Molecular Biology and Genetics, Seoul National University, Seoul 151-742, Republic of Korea
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Ross PJ, Ragina NP, Rodriguez RM, Iager AE, Siripattarapravat K, Lopez-Corrales N, Cibelli JB. Polycomb gene expression and histone H3 lysine 27 trimethylation changes during bovine preimplantation development. Reproduction 2008; 136:777-85. [PMID: 18784248 DOI: 10.1530/rep-08-0045] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Trimethylation of histone H3 at lysine 27 (H3K27me3) is established by polycomb group genes and is associated with stable and heritable gene silencing. The aim of this study was to characterize the expression of polycomb genes and the dynamics of H3K27me3 during bovine oocyte maturation and preimplantation development. Oocytes and in vitro-produced embryos were collected at different stages of development. Polycomb gene expression was analyzed by real-time quantitative RT-PCR and immunofluorescence. Global H3K27me3 levels were determined by semiquantitative immunofluorescence. Transcripts for EZH2, EED, and SUZ12 were detected at all stages analyzed, with EZH2 levels being the highest of the three at early stages of development. By the time the embryo reached the blastocyst stage, the level of PcG gene mRNA levels significantly increased. Immunofluorescence staining indicated nuclear expression of EZH2 at all stages while nuclear localized EED and SUZ12 were only evident at the morula and blastocyst stages. Semiquantitative analysis of H3K27me3 levels showed that nuclear fluorescence intensity was the highest in immature oocytes, which steadily decreased after fertilization to reach a nadir at the eight-cell stage, and then increased at the blastocyst stage. These results suggest that the absence of polycomb repressive complex 2 proteins localized to the nucleus of early embryos could be responsible for the gradual decrease in H3K27me3 during early preimplantation development.
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Affiliation(s)
- Pablo J Ross
- Departments of, Animal Science Physiology, Michigan State University, East Lansing, Michigan 48824, USA
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22
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Bettegowda A, Lee KB, Smith GW. Cytoplasmic and nuclear determinants of the maternal-to-embryonic transition. Reprod Fertil Dev 2008; 20:45-53. [PMID: 18154697 DOI: 10.1071/rd07156] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Although improvements in culture systems have greatly enhanced in vitro embryo production, success rates under the best conditions are still far from ideal. The reasons for developmental arrest of the majority of in vitro produced embryos are unclear, but likely attributable, in part, to intrinsic and extrinsic influences on the cytoplasmic and/or nuclear environment of an oocyte and/or early embryo that impede normal progression through the maternal-to-embryonic transition. The maternal-to-embryonic transition is the time period during embryonic development spanning from fertilisation until when control of early embryogenesis changes from regulation by oocyte-derived factors to regulation by products of the embryonic genome. The products of numerous maternal effect genes transcribed and stored during oogenesis mediate this transition. Marked epigenetic changes to chromatin during this window of development significantly modulate embryonic gene expression. Depletion of maternal mRNA pools is also an obligatory event during the maternal-to-embryonic transition critical to subsequent development. An increased knowledge of the fundamental mechanisms and mediators of the maternal-to-embryonic transition is foundational to understanding the regulation of oocyte quality and future breakthroughs relevant to embryo production.
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Affiliation(s)
- Anilkumar Bettegowda
- Laboratory of Mammalian Reproductive Biology and Genomics, Michigan State University, East Lansing, MI 48824, USA
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23
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Mouillet JF, Yan X, Ou Q, Jin L, Muglia LJ, Crawford PA, Sadovsky Y. DEAD-box protein-103 (DP103, Ddx20) is essential for early embryonic development and modulates ovarian morphology and function. Endocrinology 2008; 149:2168-75. [PMID: 18258677 PMCID: PMC2329271 DOI: 10.1210/en.2007-1237] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The DEAD-box helicase DP103 (Ddx20, Gemin3) is a multifunctional protein that interacts with Epstein-Barr virus nuclear proteins (EBNA2/EBNA3) and is a part of the spliceosomal small nuclear ribonucleoproteins complex. DP103 also aggregates with the micro-RNA machinery complex. We have previously shown that DP103 interacts with the nuclear receptor steroidogenic factor-1 (SF-1, NR5A1), a key regulator of reproductive development, and represses its transcriptional activity. To further explore the physiological function of DP103, we disrupted the corresponding gene in mice. Homozygous Dp103-null mice die early in embryonic development before a four-cell stage. Although heterozygous mice are healthy and fertile, analysis of steroidogenic tissues revealed minor abnormalities in mutant females, including larger ovaries, altered estrous cycle, and reduced basal secretion of ACTH. Our data point to diverse functions of murine DP103, with an obligatory role during early embryonic development and also in modulation of steroidogenesis.
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Affiliation(s)
- Jean-François Mouillet
- Department of Obstetrics and Gynecology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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24
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Elis S, Batellier F, Couty I, Balzergue S, Martin-Magniette ML, Monget P, Blesbois E, Govoroun MS. Search for the genes involved in oocyte maturation and early embryo development in the hen. BMC Genomics 2008; 9:110. [PMID: 18312645 PMCID: PMC2322995 DOI: 10.1186/1471-2164-9-110] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2007] [Accepted: 02/29/2008] [Indexed: 01/01/2023] Open
Abstract
Background The initial stages of development depend on mRNA and proteins accumulated in the oocyte, and during these stages, certain genes are essential for fertilization, first cleavage and embryonic genome activation. The aim of this study was first to search for avian oocyte-specific genes using an in silico and a microarray approaches, then to investigate the temporal and spatial dynamics of the expression of some of these genes during follicular maturation and early embryogenesis. Results The in silico approach allowed us to identify 18 chicken homologs of mouse potential oocyte genes found by digital differential display. Using the chicken Affymetrix microarray, we identified 461 genes overexpressed in granulosa cells (GCs) and 250 genes overexpressed in the germinal disc (GD) of the hen oocyte. Six genes were identified using both in silico and microarray approaches. Based on GO annotations, GC and GD genes were differentially involved in biological processes, reflecting different physiological destinations of these two cell layers. Finally we studied the spatial and temporal dynamics of the expression of 21 chicken genes. According to their expression patterns all these genes are involved in different stages of final follicular maturation and/or early embryogenesis in the chicken. Among them, 8 genes (btg4, chkmos, wee, zpA, dazL, cvh, zar1 and ktfn) were preferentially expressed in the maturing occyte and cvh, zar1 and ktfn were also highly expressed in the early embryo. Conclusion We showed that in silico and Affymetrix microarray approaches were relevant and complementary in order to find new avian genes potentially involved in oocyte maturation and/or early embryo development, and allowed the discovery of new potential chicken mature oocyte and chicken granulosa cell markers for future studies. Moreover, detailed study of the expression of some of these genes revealed promising candidates for maternal effect genes in the chicken. Finally, the finding concerning the different state of rRNA compared to that of mRNA during the postovulatory period shed light on some mechanisms through which oocyte to embryo transition occurs in the hen.
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Affiliation(s)
- Sebastien Elis
- Physiologie de Reproduction et des Comportements, UMR 6175 INRA-CNRS-Université F, Rabelais de Tours, Haras Nationaux, 37380 Nouzilly, France.
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25
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Ferg M, Sanges R, Gehrig J, Kiss J, Bauer M, Lovas A, Szabo M, Yang L, Straehle U, Pankratz MJ, Olasz F, Stupka E, Müller F. The TATA-binding protein regulates maternal mRNA degradation and differential zygotic transcription in zebrafish. EMBO J 2007; 26:3945-56. [PMID: 17703193 PMCID: PMC1950726 DOI: 10.1038/sj.emboj.7601821] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2007] [Accepted: 07/16/2007] [Indexed: 12/01/2022] Open
Abstract
Early steps of embryo development are directed by maternal gene products and trace levels of zygotic gene activity in vertebrates. A major activation of zygotic transcription occurs together with degradation of maternal mRNAs during the midblastula transition in several vertebrate systems. How these processes are regulated in preparation for the onset of differentiation in the vertebrate embryo is mostly unknown. Here, we studied the function of TATA-binding protein (TBP) by knock down and DNA microarray analysis of gene expression in early embryo development. We show that a subset of polymerase II-transcribed genes with ontogenic stage-dependent regulation requires TBP for their zygotic activation. TBP is also required for limiting the activation of genes during development. We reveal that TBP plays an important role in the degradation of a specific subset of maternal mRNAs during late blastulation/early gastrulation, which involves targets of the miR-430 pathway. Hence, TBP acts as a specific regulator of the key processes underlying the transition from maternal to zygotic regulation of embryogenesis. These results implicate core promoter recognition as an additional level of differential gene regulation during development.
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Affiliation(s)
- Marco Ferg
- Institute of Toxicology and Genetics, Forschungszentrum Karlsruhe, Eggenstein-Leopoldshafen, Germany
| | - Remo Sanges
- Bioinformatics–CBM Scrl, AREA Science Park, Basovizza, Trieste, Italy
- CBM, AREA Science Park, Basovizza, Trieste, Italy
| | - Jochen Gehrig
- Institute of Toxicology and Genetics, Forschungszentrum Karlsruhe, Eggenstein-Leopoldshafen, Germany
| | - Janos Kiss
- Institute of Agricultural Biotechnology Centre, Gödöllõ, Hungary
| | - Matthias Bauer
- Institute of Toxicology and Genetics, Forschungszentrum Karlsruhe, Eggenstein-Leopoldshafen, Germany
| | - Agnes Lovas
- Leibniz Institute for Age Research, Jena, Germany
| | - Monika Szabo
- Institute of Agricultural Biotechnology Centre, Gödöllõ, Hungary
| | - Lixin Yang
- Institute of Toxicology and Genetics, Forschungszentrum Karlsruhe, Eggenstein-Leopoldshafen, Germany
| | - Uwe Straehle
- Institute of Toxicology and Genetics, Forschungszentrum Karlsruhe, Eggenstein-Leopoldshafen, Germany
| | - Michael J Pankratz
- Institute of Toxicology and Genetics, Forschungszentrum Karlsruhe, Eggenstein-Leopoldshafen, Germany
| | - Ferenc Olasz
- Institute of Agricultural Biotechnology Centre, Gödöllõ, Hungary
| | - Elia Stupka
- Bioinformatics–CBM Scrl, AREA Science Park, Basovizza, Trieste, Italy
- CBM, AREA Science Park, Basovizza, Trieste, Italy
- Bioinformatics–CBM Scrl, AREA Science Park, ss 14 km 163.5-Basovizza, Trieste 34012, Italy. E-mail:
| | - Ferenc Müller
- Institute of Toxicology and Genetics, Forschungszentrum Karlsruhe, Eggenstein-Leopoldshafen, Germany
- Institute of Toxicology and Genetics, Forschungszentrum Karlsruhe, Herrmann von Helmholtz Platz 1, Eggenstein-Leopoldshafen 76021, Germany. Tel.: + 49 7247 823444; Fax: + 49 7247 823354; E-mail:
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26
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Hamatani T, Ko MS, Yamada M, Kuji N, Mizusawa Y, Shoji M, Hada T, Asada H, Maruyama T, Yoshimura Y. Global gene expression profiling of preimplantation embryos. Hum Cell 2007; 19:98-117. [PMID: 17204093 DOI: 10.1111/j.1749-0774.2006.00018.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Preimplantation development is marked by four major events: the transition of maternal transcripts to zygotic transcripts, compaction, the first lineage differentiation into inner cell mass and trophectoderm, and implantation. The scarcity of the materials of preimplantation embryos, both in size (diameter < 100 microm) and in quantity (only a few to tens of oocytes from each ovulation), has hampered molecular analysis of preimplantation embryos. Recent progress in RNA amplification methods and microarray platforms, including genes unique to preimplantation embryos, allow us to apply global gene expression profiling to the study of preimplantation embryos. Our gene expression profiling during preimplantation development revealed the distinctive patterns of maternal RNA degradation and embryonic gene activation, including two major transient waves of de novo transcription. The first wave corresponds to zygotic genome activation (ZGA). The second wave, mid-preimplantation gene activation (MGA), contributes dramatic morphological changes during late preimplantation development. Further expression profiling of embryos treated with inhibitors of transcription or translation revealed that the translation of maternal RNA is required for the initiation of ZGA, suggesting a cascade of gene activation from maternal RNA/protein sets to ZGA gene sets and thence to MGA gene sets. To date, several reports of microarray experiments using mouse and human preimplantation embryos have been published. The identification of a large number of genes and multiple signaling pathways involved at each developmental stage by such global gene expression profiling accelerates understanding of molecular mechanisms underlining totipotency/pluripotency and programs of early mammalian development.
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Affiliation(s)
- Toshio Hamatani
- Department of Obstetrics and Gynecology, Keio University School of Medicine, Tokyo, Japan.
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27
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Andreu-Vieyra C, Matzuk MM. Epigenetic modifications by Trithorax group proteins during early embryogenesis: do members of Trx-G function as maternal effect genes? Reprod Biomed Online 2007; 14:201-7. [PMID: 17298723 DOI: 10.1016/s1472-6483(10)60788-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Maternal effect genes encode transcripts that are expressed during oogenesis. These gene products are stored in the oocyte and become functional during resumption of meiosis and zygote genome activation, and in embryonic stem cells. To date, a few maternal effect genes have been identified in mammals. Epigenetic modifications have been shown to be important during early embryonic development and involve DNA methylation and post-translational modification of core histones. During development, two families of proteins have been shown to be involved in epigenetic changes: Trithorax group (Trx-G) and Polycomb group (Pc-G) proteins. Trx-G proteins function as transcriptional activators and have been shown to accumulate in the oocyte. Deletion of Trx-G members using conventional knockout technology results in embryonic lethality in the majority of the cases analysed to date. Recent studies using conditional knockout mice have revealed that at least one family member is necessary for zygote genome activation. We propose that other Trx-G members may also regulate embryonic genome activation and that the use of oocyte-specific deletor mouse lines will help clarify their roles in this process.
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Affiliation(s)
- Claudia Andreu-Vieyra
- Department of Pathology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
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28
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Torres-Padilla ME, Zernicka-Goetz M. Role of TIF1alpha as a modulator of embryonic transcription in the mouse zygote. ACTA ACUST UNITED AC 2006; 174:329-38. [PMID: 16880268 PMCID: PMC2064229 DOI: 10.1083/jcb.200603146] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The first events of the development of any embryo are under maternal control until the zygotic genome becomes activated. In the mouse embryo, the major wave of transcription activation occurs at the 2-cell stage, but transcription starts already at the zygote (1-cell) stage. Very little is known about the molecules involved in this process. We show that the transcription intermediary factor 1 α (TIF1α) is involved in modulating gene expression during the first wave of transcription activation. At the onset of genome activation, TIF1α translocates from the cytoplasm into the pronuclei to sites of active transcription. These sites are enriched with the chromatin remodelers BRG-1 and SNF2H. When we ablate TIF1α through either RNA interference (RNAi) or microinjection of specific antibodies into zygotes, most of the embryos arrest their development at the 2–4-cell stage transition. The ablation of TIF1α leads to mislocalization of RNA polymerase II and the chromatin remodelers SNF2H and BRG-1. Using a chromatin immunoprecipitation cloning approach, we identify genes that are regulated by TIF1α in the zygote and find that transcription of these genes is misregulated upon TIF1α ablation. We further show that the expression of some of these genes is dependent on SNF2H and that RNAi for SNF2H compromises development, suggesting that TIF1α mediates activation of gene expression in the zygote via SNF2H. These studies indicate that TIF1α is a factor that modulates the expression of a set of genes during the first wave of genome activation in the mouse embryo.
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Affiliation(s)
- Maria Elena Torres-Padilla
- The Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QR, England, UK
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29
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Bultman SJ, Gebuhr TC, Pan H, Svoboda P, Schultz RM, Magnuson T. Maternal BRG1 regulates zygotic genome activation in the mouse. Genes Dev 2006; 20:1744-54. [PMID: 16818606 PMCID: PMC1522071 DOI: 10.1101/gad.1435106] [Citation(s) in RCA: 252] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Zygotic genome activation (ZGA) is a nuclear reprogramming event that transforms the genome from transcriptional quiescence at fertilization to robust transcriptional activity shortly thereafter. The ensuing gene expression profile in the cleavage-stage embryo establishes totipotency and is required for further development. Although little is known about the molecular basis of ZGA, oocyte-derived mRNAs and proteins that alter chromatin structure are likely crucial. To test this hypothesis, we generated a maternal-effect mutation of Brg1, which encodes a catalytic subunit of SWI/SNF-related complexes, utilizing Cre-loxP gene targeting. In conditional-mutant females, BRG1-depleted oocytes completed meiosis and were fertilized. However, embryos conceived from BRG1-depleted eggs exhibited a ZGA phenotype including two-cell arrest and reduced transcription for approximately 30% of expressed genes. Genes involved in transcription, RNA processing, and cell cycle regulation were particularly affected. The early embryonic arrest is not a consequence of a defective oocyte because depleting maternal BRG1 after oocyte development is complete by RNA interference (RNAi) also resulted in two-cell arrest. To our knowledge, Brg1 is the first gene required for ZGA in mammals. Depletion of maternal BRG1 did not affect global levels of histone acetylation, whereas dimethyl-H3K4 levels were reduced. These data provide a framework for understanding the mechanism of ZGA.
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Affiliation(s)
- Scott J Bultman
- Department of Genetics and The Carolina Center for Genome Sciences, University of North Carolina, Chapel Hill, North Carolina 27599, USA.
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30
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Jeong HJ, Kim HJ, Lee SH, Kwack K, Ahn SY, Choi YJ, Kim HG, Lee KW, Lee CN, Cha KY. Gene expression profiling of the pre-implantation mouse embryo by microarray analysis: comparison of the two-cell stage and two-cell block. Theriogenology 2006; 66:785-96. [PMID: 16777209 DOI: 10.1016/j.theriogenology.2006.01.059] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2005] [Revised: 01/16/2006] [Accepted: 01/20/2006] [Indexed: 01/03/2023]
Abstract
To improve our understanding of the molecular mechanisms underlying early embryo development, further characterization of gene activity in oocytes and embryos is urgently required. The transition from the two-cell to four-cell stage is particularly important in pre-implantation embryonic development, as it involves transcriptional reprogramming and cellular differentiation. In this study, we used a 7.4 K cDNA microarray to screen mRNA transcript levels in the pre-implantation mouse embryo. Real-time PCR was used to confirm microarray data. We profiled 7,410 genes and identified 4,562 genes that were differentially expressed in the pre-implantation embryo. We selected a total of 248 genes with significant expression changes that are functionally involved in the two-cell and two-cell block embryo. Of these genes, 114 were down-regulated and the remainder (n=134) were up-regulated in the two-cell embryo. This study provides a developmental map of a large number of genes in the pre-implantation mouse embryo with particular emphasis on gene expression in the two-cell embryo and two-cell block embryo. Further investigations based on this data will provide a better understanding of the effects of various external conditions and may facilitate comparative analysis of pre-implantation development in other mammalian species, including human.
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Affiliation(s)
- Hye-Jin Jeong
- Genome Research Center for Reproductive Medicine and Infertility of Korea, Ministry of Health & Welfare, Seoul 135-081, Republic of Korea
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31
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Edwards RG. Changing genetic world of IVF, stem cells and PGD. B. Polarities and gene expression in differentiating embryo cells and stem cells. Reprod Biomed Online 2006; 11:761-76. [PMID: 16417744 DOI: 10.1016/s1472-6483(10)61696-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Novel genetic techniques in the later twentieth century led to new analytical methods for assessing the growth of embryos and stem cells and improve preimplantation diagnosis. Increasing attention to the nature of polarities in mouse and human embryos revealed the existence of an animal-vegetal axis in human oocytes and embryos. Combinations of meridional and transverse cleavage divisions, the latter due to spindle rotation, determined the unequal division of ooplasm to embryonic blastomeres. Blastomeres with differing functions were accordingly formed in 4-cell embryos, including founders of inner cell mass and trophectoderm. New forms of gene analysis led to the polymerase chain reaction, while fluorescence in-situ hybridization revealed astonishingly high degrees of heteroploidy in human embryos. Developmental genetics gained immense analytical power as cDNA libraries, microarrays, transcriptomes RNAi and other methods clarified the roles of hundreds of genes in pre- and early post-implantation embryos and stem cells.
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32
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Sohn KC, Do SI. Transcriptional regulation and O-GlcNAcylation activity of zebrafish OGT during embryogenesis. Biochem Biophys Res Commun 2005; 337:256-63. [PMID: 16188232 DOI: 10.1016/j.bbrc.2005.09.049] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2005] [Accepted: 09/09/2005] [Indexed: 10/25/2022]
Abstract
Zebrafish OGT (zOGT) sequence was identified in zebrafish (Danio rerio) genome and six different transcriptional variants of zOGT, designated var1 to var6, were isolated. Here we describe the developmental regulation of zOGT variants at transcriptional level and characterization of their OGT activities of protein O-GlcNAcylation. OGT transcriptional variants in zebrafish were differentially generated by alternative splicing and in particular, var1 and var2 were contained by 48 bp intron as a novel exon sequence, demonstrating that this form of OGT was not found in mammals. Transcript analysis revealed that var1 and var2 were highly expressed at early phase of development including unfertilized egg until dome stage whereas var3 and var4 were begins to be expressed at sphere stage until late phase of development. Our data indicate that var1 and var2 are likely to be maternal transcripts. The protein expression assay in Escherichia coli-p62 system showed that OGT activities of var3 and var4 were found to be only active whereas those of other variants were inactive.
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Affiliation(s)
- Kyung-Cheol Sohn
- Ajou University, Department of Life Science, Laboratory of Functional Glycomics, Republic of Korea
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33
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Ko MSH. Molecular biology of preimplantation embryos: primer for philosophical discussions. Reprod Biomed Online 2005; 10 Suppl 1:80-7. [PMID: 15820015 DOI: 10.1016/s1472-6483(10)62212-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
This article is based on a presentation at the First International Conference on Ethics, Science and Moral Philosophy of Assisted Human Reproduction. The goal is to provide scientific background for the discussion of philosophic issues. Recent advances in the systematic molecular analysis of preimplantation embryos are summarized, including the molecular identification of nearly all genes involved in preimplantation development and their detailed expression patterns. Notwithstanding a quantum leap in molecular understanding of preimplantation embryos, molecular evidence seems to provide no decisive definition of a threshold for the beginning of human life during preimplantation development.
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Affiliation(s)
- Minoru S H Ko
- Developmental Genomics and Ageing Section, Laboratory of Genetics, National Institute on Ageing, National Institutes of Health, Baltimore, MD 21224, USA
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34
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Edwards RG. Changing genetic world of IVF, stem cells and PGD. C. Embryogenesis and the differentiation of the haemopoietic system. Reprod Biomed Online 2005; 11:777-85. [PMID: 16417746 DOI: 10.1016/s1472-6483(10)61697-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
In this final review, attention is focused on the formation of several haemopoietic systems and their genetic markers. Very early haemopoietic precursors have been identified in mesoderm and yolk sac, as interactions arise between haemopoietic stem cells (HSC) and mesenchymal stem cells (MSC). The foundation cell for the haemopoietic system has not been identified, although several candidate cells carrying specific markers have been recognized and are highly pluripotent. Haemangioblasts were proposed as the founder haemopoietic stem cell. They may be the source of pluripotent haemopoietic cells formed in blastocyst injection chimaeras, a characteristic typical of ES cells. Their role as the founder cell of haemopoietic and mesenchymal tissues is discussed.
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35
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Rossiter H, Barresi C, Pammer J, Rendl M, Haigh J, Wagner EF, Tschachler E. Loss of vascular endothelial growth factor a activity in murine epidermal keratinocytes delays wound healing and inhibits tumor formation. Cancer Res 2004; 64:3508-16. [PMID: 15150105 DOI: 10.1158/0008-5472.can-03-2581] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The angiogenic cytokine vascular endothelial growth factor (VEGF)-A plays a central role in both wound healing and tumor growth. In the skin, epidermal keratinocytes are a major source of this growth factor. To study the contribution of keratinocyte-derived VEGF-A to these angiogenesis-dependent processes, we generated mice in which this cytokine was inactivated specifically in keratin 5-expressing tissues. The mutant mice were macroscopically normal, and the skin capillary system was well established, demonstrating that keratinocyte-derived VEGF-A is not essential for angiogenesis in the skin during embryonic development. However, healing of full-thickness wounds in adult animals was appreciably delayed compared with controls, with retarded crust shedding and the appearance of a blood vessel-free zone underneath the newly formed epidermis. When 9,12-dimethyl 1,2-benzanthracene was applied as both tumor initiator and promoter, a total of 143 papillomas developed in 20 of 23 (87%) of control mice. In contrast, only three papillomas arose in 2 of 17 (12%) of the mutant mice, whereas the rest merely displayed epidermal thickening and parakeratosis. Mutant mice also developed only 2 squamous cell carcinomas, whereas 11 carcinomas were found in seven of the control animals. These data demonstrate that whereas keratinocyte-derived VEGF-A is dispensable for skin vascularization under physiological conditions, it plays an important albeit nonessential role during epidermal wound healing and is crucial for the development of 9,12-dimethyl 1,2-benzanthracene-induced epithelial skin tumors.
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Affiliation(s)
- Heidemarie Rossiter
- Department of Dermatology, Institute of Clinical Pathology, Medical University of Vienna, Vienna, Austria
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36
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Hamatani T, Carter MG, Sharov AA, Ko MSH. Dynamics of global gene expression changes during mouse preimplantation development. Dev Cell 2004; 6:117-31. [PMID: 14723852 DOI: 10.1016/s1534-5807(03)00373-3] [Citation(s) in RCA: 668] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Understanding preimplantation development is important both for basic reproductive biology and for practical applications including regenerative medicine and livestock breeding. Global expression profiles revealed and characterized the distinctive patterns of maternal RNA degradation and zygotic gene activation, including two major transient waves of de novo transcription. The first wave corresponds to zygotic genome activation (ZGA); the second wave, named mid-preimplantation gene activation (MGA), precedes the dynamic morphological and functional changes from the morula to blastocyst stage. Further expression profiling of embryos treated with inhibitors of transcription, translation, and DNA replication revealed that the translation of maternal RNAs is required for the initiation of ZGA. We propose a cascade of gene activation from maternal RNA/protein sets to ZGA gene sets and thence to MGA gene sets. The large number of genes identified as involved in each phase is a first step toward analysis of the complex gene regulatory networks.
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Affiliation(s)
- Toshio Hamatani
- Developmental Genomics and Aging Section, Laboratory of Genetics, National Institute on Aging, National Institutes of Health, 333 Cassell Drive, Suite 3000, Baltimore, MD 21224, USA
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37
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Kansu E. Stem cell biology and plasticity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2004; 534:47-55. [PMID: 12903710 DOI: 10.1007/978-1-4615-0063-6_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Affiliation(s)
- Emin Kansu
- Hacettepe University, Institute of Oncology, Ankara, Turkey
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38
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Müller F, Tora L. The multicoloured world of promoter recognition complexes. EMBO J 2004; 23:2-8. [PMID: 14685269 PMCID: PMC1271665 DOI: 10.1038/sj.emboj.7600027] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2003] [Accepted: 11/18/2003] [Indexed: 11/09/2022] Open
Abstract
The expression pattern of regulated genes changes dynamically depending on the developmental stage and the differentiation state of the cell. Transcription factors regulate cellular events at the gene expression level by communicating signals to the general transcription machinery that forms a preinitiation complex (PIC) at class II core promoters. Recent data strongly suggest that PICs are composed of different sets of factors at distinct promoters, reflecting the spatiotemporal profile of gene expression in multicellular organisms. Thus, today it is important to ask the question: how universal are the promoter recognition factors? This review will focus on findings that support the new idea that core promoter recognition by distinct factors is an additional level of transcriptional regulation and that this step is developmentally regulated.
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Affiliation(s)
- Ferenc Müller
- Institute of Toxicology and Genetics, Forschungszentrum, Karlsruhe, Germany
| | - Làszlò Tora
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, Illkirch Cedex, CU de Strasbourg, France
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39
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Ko MSH. Embryogenomics of pre-implantation mammalian development: current status. Reprod Fertil Dev 2004. [DOI: 10.1071/rd03080] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Pre-implantation development is marked by many critical molecular events, including the maternal to zygotic transition and the first differentiation of cells. Understanding such events is important, for both basic reproductive biology and practical applications, including regenerative medicine and livestock production. Scarcity of materials has hampered the progress of the field, but systematic genomics approaches are beginning to be applied to the study of pre-implantation development, resulting in unprecedented amounts of data about the pre-implantation process. The first step in embryogenomics is to collect and sequence cDNAs (expressed sequence tags (ESTs)) for genes that are expressed and function in these early embryos. Mouse work is the most advanced, with 140111 ESTs derived from all stages of pre-implantation development currently available in the public sequence database. For other mammals, at present only approximately 1000 ESTs can be found in the public database, but efforts by several groups are generating cDNA libraries and ESTs. In the present review, the current status of the implementation of these investigative tools for mammalian pre-implantation embryos is discussed.
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40
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Knowles BB, Evsikov AV, de Vries WN, Peaston AE, Solter D. Molecular control of the oocyte to embryo transition. Philos Trans R Soc Lond B Biol Sci 2003; 358:1381-7. [PMID: 14511485 PMCID: PMC1693239 DOI: 10.1098/rstb.2003.1330] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The elucidation of the molecular control of the initiation of mammalian embryogenesis is possible now that the transcriptomes of the full-grown oocyte and two-cell stage embryo have been prepared and analysed. Functional annotation of the transcriptomes using gene ontology vocabularies, allows comparison of the oocyte and two-cell stage embryo between themselves, and with all known mouse genes in the Mouse Genome Database. Using this methodology one can outline the general distinguishing features of the oocyte and the two-cell stage embryo. This, when combined with oocyte-specific targeted deletion of genes, allows us to dissect the molecular networks at play as the differentiated oocyte and sperm transit into blastomeres with unlimited developmental potential.
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Affiliation(s)
- Barbara B Knowles
- The Jackson Laboratory, 600 East Main Street, Bar Harbor, ME 04609, USA.
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41
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Kim JM, Ogura A, Nagata M, Aoki F. Analysis of the mechanism for chromatin remodeling in embryos reconstructed by somatic nuclear transfer. Biol Reprod 2002; 67:760-6. [PMID: 12193382 DOI: 10.1095/biolreprod.101.000612] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
The objective of the present study was to understand the molecular/biochemical nature of chromatin remodeling that occurs in the somatic nuclei transferred into oocytes. We produced the reconstructed mouse embryos by two different protocols of nuclear transfer. The nucleus of a cumulus cell was transferred into enucleated unfertilized oocytes (transferred before activation, TA protocol) or activated oocytes (activated before transfer, AT protocol). More than half (56.1%) of the embryos reconstructed using the TA protocol developed to the morula/blastocyst stage, whereas very few (1.0%) of the embryos reconstructed using the AT protocol reached the morula/blastocyst stage. These embryos were analyzed for the events associated with transcriptional regulation. Changes in transcriptional activity, nuclear accumulation of TATA box binding protein (TBP), and DNase I sensitivity were examined after nuclear transfer. In the embryos reconstructed by TA protocol, all of these events occurred in a manner similar to that in the control diploid parthenogenetic embryos. The transcriptional activity was silenced after nuclear transfer and resumed at the late 1-cell stage. TBP was displaced and subsequently accumulated at the early and the late 1-cell stage, respectively. DNase I sensitivity was increased and then decreased at the early and late 1-cell stage, respectively. In contrast, embryos reconstructed using the AT protocol did not show such changes in transcriptional activity, TBP accumulation, and DNase I sensitivity. These events would be necessary for differentiated nuclei to restore totipotency and are useful indices to evaluate successful chromatin remodeling.
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Affiliation(s)
- Jin-Moon Kim
- Department of Veterinary Science, National Institute of Infectious Diseases, Tokyo 162-8640, Japan
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42
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Kobayashi A, Akasaka K, Kawaichi M, Kokubo T. Functional interaction between TATA and upstream CACGTG elements regulates the temporally specific expression of Otx mRNAs during early embryogenesis of the sea urchin, Hemicentrotus pulcherrimus. Nucleic Acids Res 2002; 30:3034-44. [PMID: 12136085 PMCID: PMC135759 DOI: 10.1093/nar/gkf439] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2002] [Accepted: 05/27/2002] [Indexed: 11/12/2022] Open
Abstract
The orthodenticle-related protein (HpOtx) gene derived from the sea urchin Hemicentrotus pulcherrimus encodes two distinct isoforms, HpOtxE and HpOtxL, which are differentially expressed during early embryogenesis and are driven by TATA-less and TATA-containing promoters, respectively. In order to determine if the TATA element is involved in the establishment of the temporally specific expression profile of the HpOtx gene, reporter genes under the control of modified or wild-type HpOtxE/L promoters were introduced into fertilized eggs. When the activities of the different promoter constructs were examined, we found that deletion of the TATA element from the HpOtxL promoter causes early expression, whereas addition of the TATA element to the HpOtxE promoter causes delayed expression. This suppressive action of the TATA element on transcription from the HpOtxE/L promoters requires the presence of upstream CACGTG elements. These results indicate that the presence or absence of the TATA element determines, at least in part, the expression profile of the HpOtxE/L promoters, in concert with the transcription factor(s) that binds to the upstream CACGTG element. Immunoblot and gel retardation analyses suggest that functional interaction between CACGTG binding factor(s) and TATA factor(s) may be regulated by an unidentified third factor(s) during early embryogenesis in the sea urchin.
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MESH Headings
- Amino Acid Sequence
- Animals
- Base Sequence
- DNA, Complementary/chemistry
- DNA, Complementary/genetics
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- Electrophoretic Mobility Shift Assay
- Embryo, Nonmammalian/metabolism
- Gene Expression Regulation, Developmental
- Homeodomain Proteins/genetics
- Luciferases/genetics
- Luciferases/metabolism
- Molecular Sequence Data
- Otx Transcription Factors
- Promoter Regions, Genetic/genetics
- Protein Binding
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/metabolism
- Regulatory Sequences, Nucleic Acid/genetics
- Regulatory Sequences, Nucleic Acid/physiology
- Sea Urchins/embryology
- Sea Urchins/genetics
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- TATA Box/genetics
- TATA Box/physiology
- TATA-Box Binding Protein
- Transcription Factors/genetics
- Transcription Factors/metabolism
- Upstream Stimulatory Factors
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Affiliation(s)
- Akiko Kobayashi
- Division of Gene Function in Animals, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0101, Japan
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43
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Shimuta K, Nakajo N, Uto K, Hayano Y, Okazaki K, Sagata N. Chk1 is activated transiently and targets Cdc25A for degradation at the Xenopus midblastula transition. EMBO J 2002; 21:3694-703. [PMID: 12110582 PMCID: PMC125399 DOI: 10.1093/emboj/cdf357] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
In Xenopus embryos, cell cycle elongation and degradation of Cdc25A (a Cdk2 Tyr15 phosphatase) occur naturally at the midblastula transition (MBT), at which time a physiological DNA replication checkpoint is thought to be activated by the exponentially increased nucleo-cytoplasmic ratio. Here we show that the checkpoint kinase Chk1, but not Cds1 (Chk2), is activated transiently at the MBT in a maternal/zygotic gene product-regulated manner and is essential for cell cycle elongation and Cdc25A degradation at this transition. A constitutively active form of Chk1 can phosphorylate Cdc25A in vitro and can target it rapidly for degradation in pre-MBT embryos. Intriguingly, for this degradation, however, Cdc25A also requires a prior Chk1-independent phosphorylation at Ser73. Ectopically expressed human Cdc25A can be degraded in the same way as Xenopus Cdc25A. Finally, Cdc25A degradation at the MBT is a prerequisite for cell viability at later stages. Thus, the physiological replication checkpoint is activated transiently at the MBT by developmental cues, and activated Chk1, only together with an unknown kinase, targets Cdc25A for degradation to ensure later development.
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Affiliation(s)
| | | | | | | | - Kenji Okazaki
- Department of Biology, Graduate School of Sciences, Kyushu University, Hakozaki 6-10-1, Fukuoka 812-8581 and
Department of Molecular Biology, Biomolecular Engineering Research Institute, Furuedai 6-2-3, Suita, Osaka 565-0874, Japan Corresponding author e-mail: K.Shimuta and N.Nakajo contributed equally to this work
| | - Noriyuki Sagata
- Department of Biology, Graduate School of Sciences, Kyushu University, Hakozaki 6-10-1, Fukuoka 812-8581 and
Department of Molecular Biology, Biomolecular Engineering Research Institute, Furuedai 6-2-3, Suita, Osaka 565-0874, Japan Corresponding author e-mail: K.Shimuta and N.Nakajo contributed equally to this work
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44
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Anderson JE, Matteri RL, Abeydeera LR, Day BN, Prather RS. Degradation of maternal cdc25c during the maternal to zygotic transition is dependent upon embryonic transcription. Mol Reprod Dev 2001; 60:181-8. [PMID: 11553916 DOI: 10.1002/mrd.1075] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
To gain a better understanding of the molecular differences that may contribute to cleavage arrest and the poorer development associated with laboratory produced embryos, a series of experiments were conducted to quantitate the message levels of the cell cycle controller cdc25c, over the maternal to zygotic transition (MZT) in 4-cell in vivo- and in vitro-derived porcine embryos. The experiments were designed to measure both maternal and embryonic derived cdc25c transcripts by quantitative reverse transcription-competitive polymerase chain reaction (RT-cPCR), determine the point of the transition to zygotic genome activation, and study the interaction between initial embryonic transcription and maternal cdc25c degradation. Analysis of in vivo- and in vitro-derived embryos revealed no difference in cdc25c message level for any of the times P4CC (P > 0.05). Comparison of control embryos from 5- to 33-hr P4CC revealed a reduction in transcript quantities in the 10-hr P4CC group that was maintained at later time points (P < 0.05). Embryos cultured in the RNA polymerase inhibitor, alpha-amanitin, from cleavage to 5-, 10-, 18-, 25-, or 33-hr P4CC displayed no difference in cdc25c levels when compared to controls at similar time points (P > 0.05). However, if embryos were first exposed to alpha-amanitin after 18-hr P4CC with this treatment continuing to 33 hr, the levels of cdc25c transcript were reduced (P < 0.04) when compared to those embryos that were first exposed to the inhibitor at either 5- or 10-hr P4CC. This finding and the comparison of these same embryos to the 0-33-hr alpha-amanitin and control groups allowed us to conclude that cdc25c transcription began between 10- and 18-hr P4CC, with the degradation of maternal cdc25c message dependent on transcriptional initiation.
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Affiliation(s)
- J E Anderson
- Department of Animal Science, University of Missouri, Columbia, Missouri 65211, USA
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45
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Shestakova E, Bandu MT, Doly J, Bonnefoy E. Inhibition of histone deacetylation induces constitutive derepression of the beta interferon promoter and confers antiviral activity. J Virol 2001; 75:3444-52. [PMID: 11238870 PMCID: PMC114137 DOI: 10.1128/jvi.75.7.3444-3452.2001] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2000] [Accepted: 01/03/2001] [Indexed: 11/20/2022] Open
Abstract
The induction of alpha/beta interferon (IFN-alpha/beta) genes constitutes one of the first responses of the cell to virus infection. The IFN-beta gene is constitutively repressed in uninfected cells and is transiently activated after virus infection. In this work we demonstrate that histone deacetylation regulates the silent state of the murine IFN-beta gene. Using chromatin immunoprecipitation (ChIP) assays, we show a direct in vivo correlation between the transcriptionally silent state and a state of hypoacetylation of histone H4 on the IFN-beta promoter region. Trichostatin A (TSA), a specific inhibitor of histone deacetylases, induced strong, constitutive derepression of the murine IFN-beta promoter stably integrated into a chromatin context, as well as the hyperacetylation of histone H4, without requiring de novo protein synthesis. We also show in this work that TSA treatment strongly enhances the endogenous IFN level and confers an antiviral state to murine fibroblastic L929 cells. Inhibition of histone deacetylation with TSA protected the cells against the lost of viability induced by vesicular stomatitis virus (VSV) and inhibited VSV multiplication. Using antibodies neutralizing IFN-alpha/beta, we show that the antiviral state induced by TSA is due to TSA-induced IFN production. The demonstration of the predominant role of histone deacetylation during the regulation of the constitutive repressed state of the IFN-beta promoter constitutes an interesting advance on the understanding of the negative regulation of this gene and opens up the possibility of new therapeutic perspectives.
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Affiliation(s)
- E Shestakova
- Laboratoire de Régulation de la Transcription et Maladies Génétiques, CNRS, UPR2228, UFR Biomédicale, Université René Descartes, 75270 Paris Cedex 06, France
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46
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Ohno M, Aoki N, Sasaki H. Allele-specific detection of nascent transcripts by fluorescence in situ hybridization reveals temporal and culture-induced changes in Igf2 imprinting during pre-implantation mouse development. Genes Cells 2001; 6:249-59. [PMID: 11260268 DOI: 10.1046/j.1365-2443.2001.00417.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Genomic imprinting causes parental-origin-specific monoallelic transcription of a subset of mammalian genes in the embryo and adult. There is conflicting evidence, however, for the monoallelic transcription of some imprinted genes, such as Igf2, in pre-implantation embryos. RESULTS We have developed an allele-specific fluorescence in situ hybridization method which involves a pair of oligonucleotide probes designed to detect an intronic polymorphism. The method, called ASO-RNA-FISH, enabled us to distinguish allelic nascent Igf2 transcripts in the cell nuclei of early mouse embryos, avoiding signals from the stored oocyte-specific transcripts. Igf2 transcription was first detectable in two-cell embryos, and biallelic transcription was predominant up to the morula stage. Then, the maternal allele became silenced during the blastocyst stage. When embryos were cultured in vitro, however, a strong bias to maternal transcription was observed up to the morula stage. CONCLUSION ASO-RNA-FISH revealed that a transition of Igf2 from biallelic to monoallelic transcription occurs in the blastocyst stage. This developmental regulation was modified temporarily by in vitro culture, suggesting a possible link between altered imprinting and abnormalities of the foetuses experienced in vitro culture. ASO-RNA-FISH is therefore a powerful technique for the study of allele-specific gene expression.
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Affiliation(s)
- M Ohno
- Division of Disease Genes, Institute of Genetic Information, Kyushu University, Maidashi, Fukuoka 812-8582, Japan
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47
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Mohamed OA, Bustin M, Clarke HJ. High-mobility group proteins 14 and 17 maintain the timing of early embryonic development in the mouse. Dev Biol 2001; 229:237-49. [PMID: 11133167 DOI: 10.1006/dbio.2000.9942] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The high-mobility group (HMG) proteins 14 and 17 are abundant chromosomal proteins that bind to nucleosomes and enhance transcription. We report that both mRNA species and both proteins are present throughout oogenesis and preimplantation development of the mouse. When antisense oligonucleotides targeting each mRNA species are injected into one-cell embryos, the proteins become depleted at the two- and four-cell stages and reaccumulate at the eight-cell stage. One-cell embryos injected with antisense oligonucleotides targeting both HMG-14 and HMG-17 cleave to the two-cell stage. Subsequent cleavages, however, are delayed compared with control-injected embryos. Nevertheless, these embryos ultimately reach the blastocyst stage. Similarly, injection into the nuclei of two-cell embryos of a peptide corresponding to the common nucleosome-binding domain of HMG-14 and HMG-17 delays progression to the four-cell stage. Furthermore, both RNA and protein synthesis is transiently reduced in antisense-injected embryos compared with injected controls. These results identify HMG-14 and HMG-17 as constitutive components of mouse oocyte and embryonic chromatin and establish a link between the structure of embryonic chromatin and the normal progression of embryonic development.
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Affiliation(s)
- O A Mohamed
- Department of Obstetrics & Gynecology, McGill University, Montreal, Quebec, H3A 1A1, Canada
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48
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Abstract
In response to DNA damage, cell-cycle checkpoints integrate cell-cycle control with DNA repair. The idea that checkpoint controls are an integral component of normal cell-cycle progression has arisen as a result of studies in Drosophila and mice. In addition, an appreciation that DNA damage arises as a natural consequence of cellular metabolism, including DNA replication itself, has influenced thinking regarding the nature of checkpoint pathways.
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Affiliation(s)
- N C Walworth
- Department of Pharmacology, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, 675 Hoes Lane, Piscataway, New Jersey 08854-5635, USA.
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49
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Abstract
Chromatin and chromosomes have major regulatory roles in development. Nucleosome positioning and modification, chromatin structural transitions and domain organization all contribute to the regulation of individual genes and gene families. Chromosomal position and nuclear compartmentalization represent important contributory factors in determining cell fate. These controls may explain many interesting and unexplored features of developmental systems.
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Affiliation(s)
- D Vermaak
- Laboratory of Molecular Embryology, National Institute of Child Health and Human Development, Bethesda, Maryland 20892-5431, USA.
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50
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Renner U, Ghidelli S, Schäfer MA, Wiśniewski JR. Alterations in titer and distribution of high mobility group proteins during embryonic development of Drosophila melanogaster. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1475:99-108. [PMID: 10806344 DOI: 10.1016/s0304-4165(00)00054-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
High mobility group proteins are thought to have an architectural function in chromatin. Here we describe changes in titers, extent of phosphorylation, and cellular distribution of the three abundant HMG proteins during embryonic development of Drosophila. The titers of the HMG proteins HMGD, HMGZ, and D1 are highest in ovaries and at the beginning of embryonic development. They decrease continuously until cellularization of the embryo. Relative to the histone H1 titer, the levels of HMGD and D1 remain almost constant during gastrulation and organogenesis, whereas the titer of HMGZ increases during late organogenesis. Up to gastrulation, the development is accompanied by dephosphorylation of D1. In contrast, HMGD and HMGZ appear to be constitutively phosphorylated. As the high extent of phosphorylation of D1 is also characteristic in ovaries, it is likely that the posttranslational modifications of this protein observed in early embryonic stages are of maternal origin. Using site specific antibodies against helices I and III of HMGD and HMGZ and against the AT-hook motif of D1, protein-specific staining patterns have been observed during embryonic development. Despite high levels of HMG proteins at the beginning of embryonic development, we were unable to detect any of these proteins in nuclei of stage 2 embryos. The accumulation of the HMG proteins correlates with the onset of transcription in stage 3. Our results argue against a proposal of a shared role of HMGD and histone H1 in Drosophila chromatin.
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Affiliation(s)
- U Renner
- III. Zoologisches Institut-Entwicklungsbiologie, Universität Göttingen, D-37073, Göttingen, Germany
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