Mechanisms of cohesin loading in meiosis

Abstract

Cohesin loading is crucial for sister chromatid cohesion, genome organization and transcription. In budding yeast, the cohesin loader complex is composed of Scc2NIPBL and Scc4MAU2. Previous work on mitotic cells identified a conserved patch on the Scc4 that was specifically important for cohesin loading at centromeres, but not on chromosome arms. However, in meiosis, Scc4 patch was shown to be important not only for centromeric loading, but also for genome-wide loading. This suggests that the Scc4-patch targets cohesin loading to additional sites in meiosis. Furthermore, both conversion and de novo cohesion establishment pathways are required in meiosis, unlike mitosis. I hypothesize that Scc4-patch mediated meiosis-specific mode of cohesin loading may facilitate the de novo cohesion establishment pathway at replication forks. In this thesis, I aim to elucidate the molecular mechanism of Scc4-patch dependent cohesion establishment pathway in meiosis.