H3/H4 acetylation at the centromere is Hat1 dependent and mitotically regulated
•
The Nrc1 bromodomain subunit of NCT shows a preference for hyperacetylated H4
•
NCT and condensin briefly colocalize during chromosome condensation and decondensation
•
Mutant Hat1/NCT rescue mutant condensin and improve mitotic chromosome structure
Summary
Condensin is a central regulator of mitotic genome structure with mutants showing poorly condensed chromosomes and profound segregation defects. Here, we identify NCT, a complex comprising the Nrc1 BET-family tandem bromodomain protein (SPAC631.02), casein kinase II (CKII), and several TAFs, as a regulator of condensin function. We show that NCT and condensin bind similar genomic regions but only briefly colocalize during the periods of chromosome condensation and decondensation. This pattern of NCT binding at the core centromere, the region of maximal condensin enrichment, tracks the abundance of acetylated histone H4, as regulated by the Hat1-Mis16 acetyltransferase complex and recognized by the first Nrc1 bromodomain. Strikingly, mutants in NCT or Hat1-Mis16 restore the formation of segregation-competent chromosomes in cells containing defective condensin. These results are consistent with a model where NCT targets CKII to chromatin in a cell-cycle-directed manner in order to modulate the activity of condensin during chromosome condensation and decondensation.
Graphical Abstract
Cited by (0)
This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.