Cohesin and Polycomb proteins functionally interact to control transcription at silenced, restrained, and active genes [expression array data]

Cohesin is crucial for proper chromosome segregation, but also regulates gene transcription and organism development by poorly understood mechanisms. We find that in Drosophila, cohesin functionally interacts with Polycomb group (PcG) silencing proteins at both silenced and active genes. Cohesin unexpectedly facilitates binding of Polycomb Repressive Complex 1 (PRC1) to many active genes. In contrast, cohesin and PRC1 binding are mutually antagonistic at silenced genes. PRC1 depletion decreases phosphorylated RNA polymerase and mRNA at many active genes, but increases them at silenced genes. Cohesin also facilitates long-range interactions between Polycomb Response Elements in the invected-engrailed gene complex where it represses transcription. These multiple distinct cohesin-PcG interactions reveal a previously unrecognized role for PRC1 in facilitating productive gene transcription, and provide new insights into how cohesin and PRC1 control development.

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Schaaf CA, Misulovin Z, Gause M, Koenig A, Gohara DW, Watson A, Dorsett D