RRC ID 45635
Author Roelens B, Schvarzstein M, Villeneuve AM.
Title Manipulation of Karyotype in Caenorhabditis elegans Reveals Multiple Inputs Driving Pairwise Chromosome Synapsis During Meiosis.
Journal Genetics
Abstract Meiotic chromosome segregation requires pairwise association between homologs, stabilized by the synaptonemal complex (SC). Here, we investigate factors contributing to pairwise synapsis by investigating meiosis in polyploid worms. We devised a strategy, based on transient inhibition of cohesin function, to generate polyploid derivatives of virtually any Caenorhabditis elegans strain. We exploited this strategy to investigate the contribution of recombination to pairwise synapsis in tetraploid and triploid worms. In otherwise wild-type polyploids, chromosomes first sort into homolog groups, then multipartner interactions mature into exclusive pairwise associations. Pairwise synapsis associations still form in recombination-deficient tetraploids, confirming a propensity for synapsis to occur in a strictly pairwise manner. However, the transition from multipartner to pairwise association was perturbed in recombination-deficient triploids, implying a role for recombination in promoting this transition when three partners compete for synapsis. To evaluate the basis of synapsis partner preference, we generated polyploid worms heterozygous for normal sequence and rearranged chromosomes sharing the same pairing center (PC). Tetraploid worms had no detectable preference for identical partners, indicating that PC-adjacent homology drives partner choice in this context. In contrast, triploid worms exhibited a clear preference for identical partners, indicating that homology outside the PC region can influence partner choice. Together, our findings, suggest a two-phase model for C. elegans synapsis: an early phase, in which initial synapsis interactions are driven primarily by recombination-independent assessment of homology near PCs and by a propensity for pairwise SC assembly, and a later phase in which mature synaptic interactions are promoted by recombination.
Volume 201(4)
Pages 1363-79
Published 2015-12-1
DOI 10.1534/genetics.115.182279
PII genetics.115.182279
PMID 26500263
PMC PMC4676528
MeSH Animals Caenorhabditis elegans / genetics* Caenorhabditis elegans Proteins / antagonists & inhibitors Caenorhabditis elegans Proteins / physiology Cell Cycle Proteins / antagonists & inhibitors Cell Cycle Proteins / physiology Chromosomal Proteins, Non-Histone / antagonists & inhibitors Chromosomal Proteins, Non-Histone / physiology Chromosome Pairing* Chromosome Segregation Female Karyotype Male Meiosis* Models, Genetic Tetraploidy
IF 3.564
Times Cited 4
C.elegans tm2543