Hallson, G., Syrzycka, M., Beck, S.A., Kennison, J.A., Dorsett, D., Page, S.L., Hunter, S.M., Keall, R., Warren, W.D., Brock, H.W., Sinclair, D.A.R., Honda, B.M. (2008). The Drosophila cohesin subunit Rad21 is a trithorax group (trxG) protein.  Proc. Natl. Acad. Sci. U.S.A. 105(34): 12405--12410.

FBrf0205879

Research paper

The cohesin complex is a key player in regulating cell division. Cohesin proteins SMC1, SMC3, Rad21, and stromalin (SA), along with associated proteins Nipped-B, Pds5, and EcoI, maintain sister chromatid cohesion before segregation to daughter cells during anaphase. Recent chromatin immunoprecipitation (ChIP) data reveal extensive overlap of Nipped-B and cohesin components with RNA polymerase II binding at active genes in Drosophila. These and other data strongly suggest a role for cohesion in transcription; however, there is no clear evidence for any specific mechanisms by which cohesin and associated proteins regulate transcription. We report here a link between cohesin components and trithorax group (trxG) function, thus implicating these proteins in transcription activation and/or elongation. We show that the Drosophila Rad21 protein is encoded by verthandi (vtd), a member of the trxG gene family that is also involved in regulating the hedgehog (hh) gene. In addition, mutations in the associated protein Nipped-B show similar trxG activity i.e., like vtd, they act as dominant suppressors of Pc and hh(Mrt) without impairing cell division. Our results provide a framework to further investigate how cohesin and associated components might regulate transcription.

PMC2527924 (PMC) (EuropePMC)