The Drosophila cohesin subunit Rad21 is a trithorax group (trxG) protein.
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.
Hallson
Graham
G
Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada V5A 1S6.
Syrzycka
Monika
M
Beck
Samantha A
SA
Kennison
James A
JA
Dorsett
Dale
D
Page
Scott L
SL
Hunter
Sally M
SM
Keall
Rebecca
R
Warren
William D
WD
Brock
Hugh W
HW
Sinclair
Donald A R
DA
Honda
Barry M
BM
D000818:Animals; D018797:Cell Cycle Proteins / Q000737:chemistry* / Q000145:classification / Q000502:physiology*; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry* / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000235:genetics; D004330:Drosophila; D029721:Drosophila Proteins / Q000145:classification / Q000235:genetics / Q000502:physiology*; D004625:Embryo, Nonmammalian; D005786:Gene Expression Regulation; D014158:Transcription, Genetic; D000097722:Cohesins
D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D000097722:Cohesins; C119839:nipped-B protein, Drosophila; C512571:trx protein, Drosophila; C410884:vtd protein, Drosophila