Okinawa, Japan, December 14, 2010 — Ms. Akai and Dr. Yanagida of the G0 Cell Unit of the Okinawa Institute of Science and Technology (OIST) and their colleagues have elucidated, a new role of condensin other than DNA packing, that is removing chromosomal components on the course of DNA reannealing activity.
Condensin is known as the protein complex required for chromosome dynamics and DNA metabolism, but its mechanism is not well understood. Condensin possesses DNA reannealing activity, an activity not found in cohesin, suggesting that DNA reannealing activity might be required for condensin function. Here, we discover the first clear role of condensin beyond chromatin packing. We found that Ssb1 proteins or RNAs bound to ssDNA were removed by condensin through DNA reannealing in vitro. Thus, condensin may reanneal and winding up DNA strands to unload chromosomal components after DNA repair and prior to mitosis.