Dr. Monika Gullerova, Sir William Dunn School of Pathology, University of Oxford
Wednesday 21st January, 4.00 p.m., Stacey Lecture Theatre 1
Cohesin is a multi-subunit protein complex essential for sister chromatid cohesion, gene expression, recombination and DNA damage repair. The underlying determinant of cohesion establishment on chromosomal arms remains enigmatic. We have successfully applied single-locus specific DNA-FISH to study cohesion dynamics in vivo, and show that topologically bound cohesive cohesin coexists with its loader Mis4Scc2-Ssl3Scc4 in fission yeast. In contrast, cohesin independent of its loader is unable to maintain stable cohesion. Cohesive sites overlap highly expressed genes and transcription inhibition reduces chromatin association of cohesion proteins. Reciprocally, heat shock induction leads to de novo recruitment of cohesive cohesin. Furthermore, cohesin and its loader physically interact with RNA Polymerase II. Finally, we show that transcription facilitates cohesin loading to chromatin in budding yeast and human cells. We suggest that transcription is the key determinant of cohesive sites on chromosomal arms in eukaryotes.