Epigenetic Regulation of Male Germ Cell Differentiation
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Male germ cell differentiation is a complex developmental program that produces highly specialized mature spermatozoa capable of independent movement and fertilization of an egg. Germ cells are unique in their capability to generate new organisms, and extra caution has to be taken to secure the correct inheritance of genetic and epigenetic information. Male germ cells are epigenetically distinct from somatic cells and they undergo several important epigenetic transitions. In primordial germ cells (PGCs), epigenome is reprogrammed by genome-wide resetting of epigenetic marks, including the sex-specific imprinting of certain genes. Postnatal spermatogenesis is characterized by drastic chromatin rearrangements during meiotic recombination, sex chromosome silencing, and compaction of sperm nuclei, which is accomplished by replacing near to all histones by sperm-specific protamines. Small RNAs, including microRNAs (miRNAs), endogenous small interfering RNAs (endo-siRNAs) and PIWI-interacting RNAs (piRNAs) are also involved in the control of male gamete production. The activities of small RNAs in male germ cells are diverse, and include miRNA- and endo-siRNA-mediated posttranscriptional mRNA regulation and piRNA-driven transposon silencing and the control of DNA methylation in PGCs. In this chapter, we give a brief review on the epigenetic processes that govern chromatin organization and germline-specific gene expression in differentiating male germ cells.
KeywordsMale Germ Cell Round Spermatid Histone Variant Pachytene Spermatocyte PIWI Protein
Work in our laboratory is supported by research grants from the Academy of Finland and Emil Aaltonen Foundation. OM and MDR are supported by the Turku Doctoral Programme of Biomedical Sciences.
- Aravin A, Gaidatzis D, Pfeffer S, Lagos-Quintana M, Landgraf P, Iovino N, Morris P, Brownstein MJ, Kuramochi-Miyagawa S, Nakano T, Chien M, Russo JJ, Ju J, Sheridan R, Sander C, Zavolan M, Tuschl T (2006) A novel class of small RNAs bind to MILI protein in mouse testes. Nature 442(7099):203–207PubMedGoogle Scholar
- Baarends WM, Wassenaar E, Hoogerbrugge JW, van Cappellen G, Roest HP, Vreeburg J, Ooms M, Hoeijmakers JH, Grootegoed JA (2003) Loss of HR6B ubiquitin-conjugating activity results in damaged synaptonemal complex structure and increased crossing-over frequency during the male meiotic prophase. Mol Cell Biol 23(4):1151–1162PubMedGoogle Scholar
- Kuramochi-Miyagawa S, Watanabe T, Gotoh K, Totoki Y, Toyoda A, Ikawa M, Asada N, Kojima K, Yamaguchi Y, Ijiri TW, Hata K, Li E, Matsuda Y, Kimura T, Okabe M, Sakaki Y, Sasaki H, Nakano T (2008) DNA methylation of retrotransposon genes is regulated by Piwi family members MILI and MIWI2 in murine fetal testes. Genes Dev 22(7):908–917PubMedGoogle Scholar
- Martianov I, Brancorsini S, Catena R, Gansmuller A, Kotaja N, Parvinen M, Sassone-Corsi P, Davidson I (2005) Polar nuclear localization of H1T2, a histone H1 variant, required for spermatid elongation and DNA condensation during spermiogenesis. Proc Natl Acad Sci U S A 102(8):2808–2813PubMedGoogle Scholar
- Papaioannou MD, Lagarrigue M, Vejnar CE, Rolland AD, Kuhne F, Aubry F, Schaad O, Fort A, Descombes P, Neerman-Arbez M, Guillou F, Zdobnov EM, Pineau C, Nef S (2010) Loss of Dicer in Sertoli cells has a major impact on the testicular proteome of mice. Mol Cell Proteomics 10(4):M900587MCP200PubMedGoogle Scholar
- Peters AH, O’Carroll D, Scherthan H, Mechtler K, Sauer S, Schofer C, Weipoltshammer K, Pagani M, Lachner M, Kohlmaier A, Opravil S, Doyle M, Sibilia M, Jenuwein T (2001) Loss of the Suv39h histone methyltransferases impairs mammalian heterochromatin and genome stability. Cell 107(3):323–337PubMedGoogle Scholar
- Roest HP, van Klaveren J, de Wit J, van Gurp CG, Koken MH, Vermey M, van Roijen JH, Hoogerbrugge JW, Vreeburg JT, Baarends WM, Bootsma D, Grootegoed JA, Hoeijmakers JH (1996) Inactivation of the HR6B ubiquitin-conjugating DNA repair enzyme in mice causes male sterility associated with chromatin modification. Cell 86(5):799–810PubMedGoogle Scholar
- Watanabe T, Takeda A, Tsukiyama T, Mise K, Okuno T, Sasaki H, Minami N, Imai H (2006) Identification and characterization of two novel classes of small RNAs in the mouse germline: retrotransposon-derived siRNAs in oocytes and germline small RNAs in testes. Genes Dev 20(13):1732–1743PubMedGoogle Scholar
- Webster KE, O’Bryan MK, Fletcher S, Crewther PE, Aapola U, Craig J, Harrison DK, Aung H, Phutikanit N, Lyle R, Meachem SJ, Antonarakis SE, de Kretser DM, Hedger MP, Peterson P, Carroll BJ, Scott HS (2005) Meiotic and epigenetic defects in Dnmt3L-knockout mouse spermatogenesis. Proc Natl Acad Sci U S A 102(11):4068–4073PubMedGoogle Scholar