Identification of chromosome sequence motifs that mediate meiotic pairing and synapsis in C. elegans

Abstract

C. elegans chromosomes contain specialized regions called pairing centers (PCs) that mediate homologous pairing and synapsis during meiosis. Four related proteins, ZIM-1, -2, -3, and HIM-8, associate with these sites and are required for their essential functions. Here we show that short sequence elements enriched in the corresponding chromosome regions selectively recruit these proteins in vivo. In vitro analysis using SELEX indicates that each protein’s binding specificity arises from a combination of two zinc fingers and an adjacent domain. Insertion of a cluster of recruiting motifs into a chromosome lacking its endogenous PC is sufficient to restore homologous pairing, synapsis, crossover recombination, and segregation. These findings help to illuminate how chromosome sites mediate essential aspects of meiotic chromosome dynamics.