Abstract
During meiotic prophase in male mammals, the X and Y chromosomes condense to form a macrochromatin body, termed the sex, or XY, body, within which X- and Y-linked genes are transcriptionally repressed. The molecular basis and biological function of both sex body formation and meiotic sex chromosome inactivation (MSCI) are unknown. A phosphorylated form of H2AX, a histone H2A variant implicated in DNA repair, accumulates in the sex body in a manner independent of meiotic recombination-associated double-strand breaks. Here we show that the X and Y chromosomes of histone H2AX-deficient spermatocytes fail to condense to form a sex body, do not initiate MSCI, and exhibit severe defects in meiotic pairing. Moreover, other sex body proteins, including macroH2A1.2 and XMR, do not preferentially localize with the sex chromosomes in the absence of H2AX. Thus, H2AX is required for the chromatin remodeling and associated silencing in male meiosis.
MeSH terms
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Animals
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Cell Nucleus / genetics
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Cell Nucleus / metabolism
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Chromatin / genetics
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Chromatin / metabolism*
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Chromosome Pairing / genetics
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism
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Gene Silencing / physiology*
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Histones / deficiency*
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Histones / genetics
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Male
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Meiosis / genetics*
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Mice
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Mice, Knockout
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Nuclear Proteins / genetics
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Nuclear Proteins / metabolism
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Protein Structure, Tertiary / genetics
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RNA Polymerase II / genetics
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RNA Polymerase II / metabolism
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Rad51 Recombinase
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Sex Chromatin / genetics
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Sex Chromatin / metabolism
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Sex Chromosome Aberrations
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Sex Chromosomes / genetics
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Sex Chromosomes / metabolism*
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Spermatocytes / metabolism*
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Spermatocytes / pathology
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Testis / abnormalities
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Testis / metabolism*
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Testis / pathology
Substances
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Chromatin
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DNA-Binding Proteins
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H2AX protein, human
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Histones
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Nuclear Proteins
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Slx protein, mouse
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XLRL protein, human
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Xlr nuclear protein, mouse
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RNA Polymerase II
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Rad51 Recombinase
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Rad51 protein, mouse