Arrested crossover precursor structures form stable homologous bonds in a Tetrahymena meiotic mutant

PLoS One. 2022 Feb 16;17(2):e0263691. doi: 10.1371/journal.pone.0263691. eCollection 2022.


Meiotic DNA double-strand breaks produce reciprocally exchanged DNA strands, which mature into chiasmata that hold homologous chromosomes together as bivalents. These bivalents are subsequently separated in the first meiotic division. In a mutant lacking the newly identified Tetrahymena gene APRO1 (Anaphase promoting 1), meiosis is arrested by the end of prophase. Mature chiasmata are not formed but bivalents are connected via a molecular precursor structure. In-depth analysis of this arrested intermediate structure may help to elucidate the noncanonical molecular recombination pathway in Tetrahymena.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chromosomes / genetics*
  • DNA Breaks, Double-Stranded*
  • DNA Repair*
  • Homologous Recombination*
  • Meiosis*
  • Tetrahymena / genetics*

Grant support

This work was supported by grant P27313-B20 from the Austrian Science Fund ( The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.