Abstract
Condensin is a multi-subunit SMC complex that binds to and compacts chromosomes. Here we addressed the regulation of condensin binding dynamics using C. elegans condensin DC, which represses X chromosomes in hermaphrodites for dosage compensation. We established fluorescence recovery after photobleaching (FRAP) using the SMC4 homolog DPY-27 and showed that a well-characterized ATPase mutation abolishes its binding. Next, we performed FRAP in the background of several chromatin modifier mutants that cause varying degrees of X-chromosome derepression. The greatest effect was in a null mutant of the H4K20me2 demethylase DPY-21, where the mobile fraction of condensin DC reduced from ~30% to 10%. In contrast, a catalytic mutant of dpy-21 did not regulate condensin DC mobility. Hi-C data in the dpy-21 null mutant showed little change compared to wild type, uncoupling Hi-C measured long-range DNA contacts from transcriptional repression of the X chromosomes. Together, our results indicate that DPY-21 has a non-catalytic role in regulating the dynamics of condensin DC binding, which is important for transcription repression.
Original language | English (US) |
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Article number | 274115 |
Journal | Journal of cell science |
Volume | 135 |
Issue number | 2 |
DOIs | |
State | Published - Jan 2022 |
Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2021. Published by The Company of Biologists Ltd.
Keywords
- C. elegans
- Condensin
- FRAP
- Hi-C
- Histone modifications
- Transcription