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RNAP II antagonizes mitotic chromatin folding and chromosome segregation by condensin.
Cell Rep, 43(3):113901.
Condensin shapes mitotic chromosomes by folding chromatin into loops, but whetherit does so by DNA-loop extrusion remains speculative. Although loop-extrudingcohesin is stalled by transcription, the impact of transcription on condensin,which is enriched at highly expressed genes in many species, remains unclear.Using degrons of Rpb1 or the torpedo nuclease Dhp1(XRN2) to either deplete ordisplace RNAPII on chromatin in fission yeast metaphase cells, we show thatRNAPII does not load condensin on DNA. Instead, RNAPII retains condensin in cisand hinders its ability to fold mitotic chromatin and to support chromosomesegregation, consistent with the stalling of a loop extruder. Transcriptiontermination by Dhp1 limits such a hindrance. Our results shed light on theintegrated functioning of condensin, and we argue that a tight control oftranscription underlies mitotic chromosome assembly by loop-extruding condensin.
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