PT  - JOURNAL ARTICLE
AU  - Julieta Rivosecchi
AU  - Laetitia Vachez
AU  - François Gautier
AU  - Pascal Bernard
AU  - Vincent Vanoosthuyse
TI  - RNA polymerase backtracking drives the accumulation of fission yeast condensin at active genes
AID  - 10.1101/2020.11.13.381434
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.11.13.381434
4099  - http://biorxiv.org/content/early/2020/11/14/2020.11.13.381434.short
4100  - http://biorxiv.org/content/early/2020/11/14/2020.11.13.381434.full
AB  - The mechanisms leading to the accumulation of the SMC complex condensin around specific transcription units in mitosis remain unclear. Observations made in bacteria suggested that RNA polymerases (RNAP) constitute an obstacle to SMC translocation, particularly when RNAP and SMC travel in opposite directions. Whether this also applies to eukaryotic condensin remains unclear. Here we show in fission yeast that condensin remains focused at the 3’ end of an RNAP2-transcribed gene after flipping its orientation, suggesting that gene termini harbor intrinsic condensin-positioning features whatever the orientation of transcription. Consistent with this, we provide evidence that transcription termination mechanisms position condensin whatever the RNAP involved. Moreover, to stabilize backtracked RNAP2 polymerases within gene bodies was sufficient to cancel the accumulation of condensin at gene termini and to redistribute it evenly within transcription units. Altogether, our results suggest that RNAP backtracking, which is frequent at gene termini, plays a key role in positioning condensin and strengthen the idea that dense arrays of proteins tightly-bound to DNA alter the distribution of condensin on mitotic chromosomes.