Updated publication reference for PubMed record(s): 28380054. The meiosis-specific chromosomal events of homolog pairing, synapsis, and recombination occur over an extended meiotic prophase I. In this study, we show that, in mice, maintenance of an extended meiotic prophase I requires the gene Meioc, a germ-cell specific factor conserved in most metazoans. Using immunoprecipitation and quantitative mass spectrometry, we identify proteins that interact with MEIOC in the mouse germ line.