This entry represents the Nipped-B protein and its homologues, including Mis4 from fission yeast, Scc2 from budding yeast and Nipbl from zebrafish and Nipped-B from Drosophila. Budding yeast Scc2 is known to be part of the loader for the cohesion to be loaded onto the chromosome []. It has also been shown to regulate gene expression independent of cohesin [].Drosophila melanogaster Nipped-B protein is a chromatin binding protein that is involved in sister chromatid cohesion. Nipped-B and its Mau-2 partner are required for cohesin to associate with chromosomes []. The Drosophila Nipped-B has also been shown to regulate gene expression []. The zebrafish Nipbl has also been shown to regulate transcription. Nipbl has the ability to interact with other molecules such as histone deacetylases, HP-1gamma, and chromatin remodelling factors. It has been suggested that Nipbl is a cohesin-asociated scaffold protein that have functions other than loading cohesin []. Mutations in the human NIPBL (Nipped-B-like) gene cause Cornelia de Lange syndrome 1 (CDLS1), a clinically heterogeneous developmental disorder associated with malformations affecting multiple systems [].
Chromobox protein homologue 3 (CBX3, also known as HP1 gamma) is a component of heterochromatin that binds histone H3 tails methylated at 'Lys-9' which leads to epigenetic repression []. By interacting with MIS12 complex, it is involved in the formation of a functional kinetochore []. It recruits NIPBL to sites of DNA damage at double-strand breaks []. It is a component of the E2F6.com-1 []and PER []complexes. The PER complex controls the circadian clock [].
This entry represents the chromatid cohesion factor Mau2 and its homologues, including Scc4 from budding yeasts and Ssl3 from fission yeasts. Scc4 is a subunit of the cohesin loading factor complex (Scc2-Scc4), which is required for the loading of cohesin complexes onto chromosomes []. Ssl3 is in complex with Mis4 (Scc2 homologue) and is required in G1 for cohesin binding to chromosomes []. Animal Mau2 interacts with Nipbl (Scc2 orthologue), and both proteins are involved in sister chromatid cohesion and segregation [, , ].