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Curr Biol. 2016 Nov 7;26(21):2873-2884. doi: 10.1016/j.cub.2016.09.007. Epub 2016 Oct 6.

A Surveillance System Ensures Crossover Formation in C. elegans.

Author information

1
Magee-Womens Research Institute, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA.
2
Max F. Perutz Laboratories, University of Vienna, Vienna Biocenter, 1030 Vienna, Austria.
3
Department of Biology, McGill University, Montreal, QC H3A 1B1, Canada.
4
Magee-Womens Research Institute, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA. Electronic address: jly@alum.mit.edu.

Abstract

Crossover (CO) recombination creates a physical connection between homologs that promotes their proper segregation at meiosis I (MI). Failure to realize an obligate CO causes homologs to attach independently to the MI spindle and separate randomly, leading to nondisjunction. However, mechanisms that determine whether homolog pairs have received crossovers remain mysterious. Here we describe a surveillance system in C. elegans that monitors recombination intermediates and couples their formation to meiotic progression. Recombination intermediates are required to activate the system, which then delays further processing if crossover precursors are lacking on even one chromosome. The synaptonemal complex, a specialized, proteinaceous structure connecting homologous chromosomes, is stabilized in cis on chromosomes that receive a crossover and is destabilized on those lacking crossovers, a process that is dependent on the function of the polo-like kinase PLK-2. These results reveal a new layer of communication between crossover-committed intermediates and the synaptonemal complex that functions as a cis-acting, obligate, crossover-counting mechanism.

KEYWORDS:

C. elegans; SUN-1; checkpoint; cosa-1; germline; him-5; meiosis; plk-2; synapsis; synaptonemal complex

PMID:
27720619
PMCID:
PMC5104180
DOI:
10.1016/j.cub.2016.09.007
[Indexed for MEDLINE]
Free PMC Article

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