Figure 1.

Overview of the recombination process during meiosis. (A) The mechanism of meiotic recombination. Double-strand breaks (DSBs) are formed by Spo11 and stabilized by the Mer2–Mei4–Rec114 (RMM) subcomplex; then they are processed by several factors, including the Mre11–Rad50–Xrs2 (MRX) complex, to yield single-stranded DNA. One of the strands invades the homologous chromosome, giving rise to a double-Holliday junction intermediate. This structure can be resolved, resulting either in crossover or non-crossover; (B) Synaptonemal complex (SC) assembly in yeast by Zip1. Zip1 protein rapidly polymerizes, which together with factors Ecm11 and Gmc2 localizes in the interior part of the complex (central element, or CE). Associations with the synapsis initiation complex (SIC), including Zip3, are necessary for a correct recruitment of the aforementioned factors. Proteins Red1 and Hop1 are responsible for lateral element (LE) formation, to which sister chromatids remain attached.