Surveillance of different recombination defects in mouse spermatocytes yields distinct responses despite elimination at an identical developmental stage

Mol Cell Biol. 2005 Aug;25(16):7203-15. doi: 10.1128/MCB.25.16.7203-7215.2005.

Abstract

Fundamentally different recombination defects cause apoptosis of mouse spermatocytes at the same stage in development, stage IV of the seminiferous epithelium cycle, equivalent to mid-pachynema in normal males. To understand the cellular response(s) that triggers apoptosis, we examined markers of spermatocyte development in mice with different recombination defects. In Spo11(-)(/)(-) mutants, which lack the double-strand breaks (DSBs) that initiate recombination, spermatocytes express markers of early to mid-pachynema, forming chromatin domains that contain sex body-associated proteins but that rarely encompass the sex chromosomes. Dmc1(-)(/)(-) spermatocytes, impaired in DSB repair, appear to arrest at or about late zygonema. Epistasis analysis reveals that this earlier arrest is a response to unrepaired DSBs, and cytological analysis implicates the BRCT-containing checkpoint protein TOPBP1. Atm(-)(/)(-) spermatocytes show similarities to Dmc1(-)(/)(-) spermatocytes, suggesting that ATM promotes meiotic DSB repair. Msh5(-)(/)(-) mutants display a set of characteristics distinct from these other mutants. Thus, despite equivalent stages of spermatocyte elimination, different recombination-defective mutants manifest distinct responses, providing insight into surveillance mechanisms in male meiosis.

Publication types

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

MeSH terms

  • Animals
  • Apoptosis
  • Chromatin / metabolism
  • DNA Repair
  • Epistasis, Genetic
  • Fluorescent Antibody Technique, Indirect
  • Gene Expression Regulation, Developmental*
  • Male
  • Meiosis
  • Mice
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Microscopy, Fluorescence
  • Models, Genetic
  • Mutation
  • Recombination, Genetic*
  • Spermatocytes / cytology*
  • Spermatocytes / metabolism
  • Testis / metabolism
  • Time Factors

Substances

  • Chromatin