Cohesin is an SMC protein complex that is best known for its role in sister chromatid cohesion. There are meiosis-specific cohesin complex components that are required for homologous chromosome pairing, recombination and synapsis in addition to sister chromatid cohesion. Mutations of these cohesin components are known to cause infertility and their mis-expression has been linked with poor cancer prognosis.
In mitotic cells, the cohesin complex is composed of a heterodimer between SMC1α and SMC3 that form a V-shaped structure that is bridged by an α-kleisin known as RAD21 and a stromal antigen protein (STAG1 or STAG2).
Meiosis-specific cohesin subunits have been characterized for most model organisms, and are required for the unique events that occur during prophase I. In mammals there is a meiosis-specific SMC1 subunit (SMC1β), two additional α-kleisins (RAD21L and REC8) and another stromal antigen protein (STAG3).
Using mouse mutant models, together with cytological and molecular techniques, our lab has delineated the functions of the meiosis-specific subunits of cohesin. Some of this work is published here: