X chromosome and autosomal recombination are differentially sensitive to disruptions in SC maintenance

Proc Natl Acad Sci U S A. 2019 Oct 22;116(43):21641-21650. doi: 10.1073/pnas.1910840116. Epub 2019 Sep 30.


The synaptonemal complex (SC) is a conserved meiotic structure that regulates the repair of double-strand breaks (DSBs) into crossovers or gene conversions. The removal of any central-region SC component, such as the Drosophila melanogaster transverse filament protein C(3)G, causes a complete loss of SC structure and crossovers. To better understand the role of the SC in meiosis, we used CRISPR/Cas9 to construct 3 in-frame deletions within the predicted coiled-coil region of the C(3)G protein. Since these 3 deletion mutations disrupt SC maintenance at different times during pachytene and exhibit distinct defects in key meiotic processes, they allow us to define the stages of pachytene when the SC is necessary for homolog pairing and recombination during pachytene. Our studies demonstrate that the X chromosome and the autosomes display substantially different defects in pairing and recombination when SC structure is disrupted, suggesting that the X chromosome is potentially regulated differently from the autosomes.

Keywords: Drosophila; homologous recombination; meiosis; synaptonemal complex.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • DNA Breaks, Double-Stranded
  • DNA Repair / genetics
  • Drosophila Proteins / genetics*
  • Drosophila melanogaster / genetics*
  • Pachytene Stage / genetics*
  • Recombination, Genetic / genetics
  • Sequence Deletion / genetics
  • Synaptonemal Complex / genetics*
  • X Chromosome / genetics*


  • C3G protein, Drosophila
  • Drosophila Proteins