The histone H4 lysine 20 demethylase DPY-21 regulates the dynamics of condensin DC binding


  • L. Breimann
  • A.K. Morao
  • J. Kim
  • D.S. Jimenez
  • N. Maryn
  • K. Bikkasani
  • M.J. Carrozza
  • S.E. Albritton
  • M. Kramer
  • L.A. Street
  • K. Cerimi
  • V.F. Schumann
  • E. Bahry
  • S. Preibisch
  • A. Woehler
  • S. Ercan


  • Journal of Cell Science


  • J Cell Sci 135 (2): jcs258818


  • Condensin is a multi-subunit structural maintenance of chromosomes (SMC) complex that binds to and compacts chromosomes. Here, we addressed the regulation of condensin binding dynamics using Caenorhabditis 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 DPY-27 binding to X chromosomes. 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 sequencing data from the dpy-21 null mutant showed little change compared to wild-type data, uncoupling Hi-C-measured long-range DNA contacts from transcriptional repression of the X chromosomes. Taken 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.