title: Distinct requirements for Sin3a in perinatal male gonocytes and differentiating spermatogonia.
abstract: Chromatin modifier Swi-independent 3a (SIN3A), together with associated histone deacetylases, influences gene expression during development and differentiation through a variety of transcription factors in a cell-specific manner. Sin3a is essential for the maintenance of inner cell mass cells of mouse blastocysts, embryonic fibroblasts, and myoblasts, but is not required for the survival of trophectoderm or Sertoli cells. To better understand how this transcriptional regulator modulates cells at different developmental stages within a single lineage, we used conditional gene targeting in mice to ablate Sin3a from perinatal quiescent male gonocytes and from postnatal differentiating spermatogonia. Mitotic germ cells expressing stimulated by retinoic acid gene 8 (Stra8) that lacked Sin3a exhibited increased DNA damage and apoptosis, yet collectively progressed through meiosis and spermiogenesis and generated epididymal sperm at approximately 50% of control levels, sufficient for normal fertility. In contrast, perinatal gonocytes lacking Sin3a underwent rapid depletion that coincided with cell cycle reentry, exhibiting 2.5-fold increased histone H3 phosphorylation upon cycling that suggested a prophase/metaphase block; germ cells were almost entirely absent two weeks after birth, resulting in sterility. Gene expression profiling of neonatal testes containing Sin3a-deleted gonocytes identified upregulated transcripts highly associated with developmental processes and pattern formation, and downregulated transcripts involved in nuclear receptor activity, including Nr4a1 (Nur77). Interestingly, Nr4a1 levels were elevated in testes containing Stra8-expressing, Sin3a-deleted spermatogonia. SIN3A directly binds to the Nr4a1 promoter, and Nr4a1 expression is diminished upon spermatogonial differentiation in vitro. We conclude that within the male germline, Sin3a is required for the mitotic reentry of gonocytes, but is dispensable for the maintenance of differentiating spermatogonia and subsequent spermatogenic processes.
authors.affiliation: Human Molecular Genetics Program, Children's Hospital of Chicago Research Center, and Department of Pediatrics and Obstetrics and Gynecology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
authors.forename: Shannon J
authors.initials: SJ
authors.lastname: Gallagher
authors.forename: Amber E
authors.initials: AE
authors.lastname: Kofman
authors.forename: Jessica M
authors.initials: JM
authors.lastname: Huszar
authors.forename: Jan-Hermen
authors.initials: JH
authors.lastname: Dannenberg
authors.forename: Ronald A
authors.initials: RA
authors.lastname: DePinho
authors.forename: Robert E
authors.initials: RE
authors.lastname: Braun
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Payne
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D017209:Apoptosis / Q000235:genetics; D002454:Cell Differentiation / Q000502:physiology*; D019070:Cell Lineage / Q000502:physiology; D047369:Chromatin Immunoprecipitation; D004249:DNA Damage / Q000235:genetics; D017931:DNA Primers / Q000235:genetics; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental / Q000235:genetics / Q000502:physiology*; D018390:Gene Targeting / Q000379:methods; D005854:Germ Cells / Q000166:cytology / Q000254:growth & development*; D006657:Histones / Q000378:metabolism; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D046228:Microarray Analysis; D057105:Nuclear Receptor Subfamily 4, Group A, Member 1 / Q000378:metabolism; D010766:Phosphorylation; D011506:Proteins / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D012097:Repressor Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D056264:Sin3 Histone Deacetylase and Corepressor Complex; D013093:Spermatogonia / Q000254:growth & development*; D013737:Testis / Q000166:cytology / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D017931:DNA Primers; D006657:Histones; C539818:Nr4a1 protein, mouse; D057105:Nuclear Receptor Subfamily 4, Group A, Member 1; D011506:Proteins; D012097:Repressor Proteins; C099683:SIN3A transcription factor; C102019:Stra8 protein, mouse; D056264:Sin3 Histone Deacetylase and Corepressor Complex