Poised chromatin and bivalent domains facilitate the mitosis-to-meiosis transition in the male germline

BMC Biol. 2015 Jul 22:13:53. doi: 10.1186/s12915-015-0159-8.

Abstract

Background: The male germline transcriptome changes dramatically during the mitosis-to-meiosis transition to activate late spermatogenesis genes and to transiently suppress genes commonly expressed in somatic lineages and spermatogenesis progenitor cells, termed somatic/progenitor genes.

Results: These changes reflect epigenetic regulation. Induction of late spermatogenesis genes during spermatogenesis is facilitated by poised chromatin established in the stem cell phases of spermatogonia, whereas silencing of somatic/progenitor genes during meiosis and postmeiosis is associated with formation of bivalent domains which also allows the recovery of the somatic/progenitor program after fertilization. Importantly, during spermatogenesis mechanisms of epigenetic regulation on sex chromosomes are different from autosomes: X-linked somatic/progenitor genes are suppressed by meiotic sex chromosome inactivation without deposition of H3K27me3.

Conclusions: Our results suggest that bivalent H3K27me3 and H3K4me2/3 domains are not limited to developmental promoters (which maintain bivalent domains that are silent throughout the reproductive cycle), but also underlie reversible silencing of somatic/progenitor genes during the mitosis-to-meiosis transition in late spermatogenesis.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cells, Cultured
  • Chromatin / chemistry
  • Chromatin / genetics*
  • Epigenesis, Genetic*
  • Gene Expression Regulation, Developmental
  • Genes, X-Linked
  • Germ Cells / cytology*
  • Germ Cells / metabolism
  • Histones / chemistry
  • Histones / genetics
  • Male
  • Meiosis*
  • Mice, Inbred C57BL
  • Mitosis*
  • Sex Chromosomes / chemistry
  • Sex Chromosomes / genetics*
  • Spermatogenesis*
  • Transcriptional Activation
  • Transcriptome
  • X Chromosome Inactivation

Substances

  • Chromatin
  • Histones