Postmeiotic Sex Chromatin in the Male Germline of Mice

Satoshi H. Namekawa, Peter J. Park, Li Feng Zhang, James E. Shima, John R. McCarrey, Michael D. Griswold, Jeannie T. Lee

Research output: Contribution to journalArticlepeer-review

313 Scopus citations

Abstract

In mammals, the X and Y chromosomes are subject to meiotic sex chromosome inactivation (MSCI) during prophase I in the male germline, but their status thereafter is currently unclear. An abundance of X-linked spermatogenesis genes has spawned the view that the X must be active [1-8]. On the other hand, the idea that the imprinted paternal X of the early embryo may be preinactivated by MSCI suggests that silencing may persist longer [9-12]. To clarify this issue, we establish a comprehensive X-expression profile during mouse spermatogenesis. Here, we discover that the X and Y occupy a novel compartment in the postmeiotic spermatid and adopt a non-Rabl configuration. We demonstrate that this postmeiotic sex chromatin (PMSC) persists throughout spermiogenesis into mature sperm and exhibits epigenetic similarity to the XY body. In the spermatid, 87% of X-linked genes remain suppressed postmeiotically, while autosomes are largely active. We conclude that chromosome-wide X silencing continues from meiosis to the end of spermiogenesis, and we discuss implications for proposed mechanisms of imprinted X-inactivation.

Original languageEnglish (US)
Pages (from-to)660-667
Number of pages8
JournalCurrent Biology
Volume16
Issue number7
DOIs
StatePublished - Apr 4 2006

Keywords

  • DEVBIO
  • DNA

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)

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