CUNY ASRC & CCNY Seminar in Biochemistry, Biophysics & Biodesign with Lu Gan, National University of Singapore


Title:Three-dimensional exploration of eukaryotic nuclei

Abstract: Chromosome organization at the nucleosome level has long been proposed to influence nuclear activities like transcription, replication, recombination, and chromosome segregation. One of the longstanding textbook models proposes that nucleosomes pack into structures called 30-nm fibers. While there are a number of competing 30-nm-fiber models, they all share common features such as compactness, a high degree of order, and a helical path of sequential nucleosomes. Such fibers are also implied to be highly abundant, explaining the disposition of the majority of nucleosomes in any given cell. We have taken advantage of advances in electron cryotomography (cryo-ET) to explore the life-like organization of chromatin in single-celled eukaryotes such as picoplankton and yeast. We have not found any evidence of 30-nm fibers in cells enriched in interphase or mitosis. Instead, chromatin packing in these cells is better explained by the alternate "liquid" chromatin model, first proposed three decades ago. To our surprise, however, the chromatin from these cells can be induced to form 30-nm fibers when isolated from cells and subjected to a low concentration of divalent cations. The physiological conditions inside cells therefore destabilize the 30-nm fiber.

 Wednesdays at noon at the CUNY ASRC Auditorium (unless otherwise noted)

Coffee/Tea: 11:30am (CUNY ASRC 1st Floor Tea Room)

The ASRC Structural Biology Initiative is proud to run a joint seminar series in Structural Biology and Biochemistry together with the CCNY Department of Chemistry. Seminars are held Wednesdays at noon in the ASRC’s main auditorium, unless otherwise noted. CUNY faculty interested in meeting with visitors are encouraged to directly contact the host at least two weeks in advance of the seminar date.

In addition, we’re proud to host a variety of workshops offering technical information on aspects of structural biology techniques.

We are happy to include listings of other New York area seminars relevant to the structural biology community; please contact Diane.Beckford@asrc.cuny.edu for more information.

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  • Start Date: 5/31/2017
  • Time: 12:00 PM - 1:30 PM
  • College: CUNY Advanced Science Research Center
  • Address: 85 St. Nicholas Terrace, Manhattan
  • Room: Auditorium
  • Phone: 212-413-3142
  • Website: Structbio.asrc.cuny.edu
  • Admission: Free