Chromatin structure undergoes marked, tightly controlled changes during the cell cycle. Maintaining proper chromatin structure is essential for faithful execution of such fundamental events as chromosome replication, recombination, gene expression or cell division. Errors in either of the processes often result in genomic instability and chromosomal alterations potentially leading to carcinogenesis or developmental defects. However molecular mechanisms underlying chromatin dynamics remain largely unknown. The SMC protein family is an emerging group of cellular ATPases responsible for large-scale chromatin reorganizations in organisms ranging from bacteria to humans. These proteins have been implicated in such diverse range of cellular functions as chromosome cohesion and condensation, DNA repair and dosage compensation. It was found recently that the mechanism of 13S condensin, a Xenopus SMC complex responsible for the chromosome condensation during cell division, involves direct ATP-dependent deformation of the large-scale DNA structure. This is an entirely novel kind of enzymatic activity. This project focuses on further mechanistic characterization of the SMC proteins using MukBEF, a bacterial analog of 13S condensin, as a model protein.
The specific aims of this project are: (1) characterize biochemical activities of MukBEF; (2) investigate cell cycle regulation of MukBEF; (3) investigate the architecture of MukBEF-DNA complex using electron microscopy; (4) investigate DNA deformation by MukBEF using single DNA manipulation technique. These studies are expected to yield a comprehensive scheme of the MukBEF-catalyzed reaction. These data will contribute to our understanding of the intracellular functions of MukBEF and will illuminate the role of SMC proteins in large scale chromatin dynamics.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM063786-05
Application #
6931544
Study Section
Biophysical Chemistry Study Section (BBCB)
Program Officer
Lewis, Catherine D
Project Start
2001-08-01
Project End
2006-07-31
Budget Start
2005-08-01
Budget End
2006-07-31
Support Year
5
Fiscal Year
2005
Total Cost
$181,875
Indirect Cost
Name
University of Oklahoma Norman
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
848348348
City
Norman
State
OK
Country
United States
Zip Code
73019
Cui, Yuanbo; Petrushenko, Zoya M; Rybenkov, Valentin V (2008) MukB acts as a macromolecular clamp in DNA condensation. Nat Struct Mol Biol 15:411-8
She, Weifeng; Wang, Qinhong; Mordukhova, Elena A et al. (2007) MukEF Is required for stable association of MukB with the chromosome. J Bacteriol 189:7062-8
Wang, Qinhong; Mordukhova, Elena A; Edwards, Andrea L et al. (2006) Chromosome condensation in the absence of the non-SMC subunits of MukBEF. J Bacteriol 188:4431-41
Petrushenko, Zoya M; Lai, Chien-Hung; Rybenkov, Valentin V (2006) Antagonistic interactions of kleisins and DNA with bacterial Condensin MukB. J Biol Chem 281:34208-17
Petrushenko, Zoya M; Lai, Chien-Hung; Rai, Rachna et al. (2006) DNA reshaping by MukB. Right-handed knotting, left-handed supercoiling. J Biol Chem 281:4606-15
Dekker, N H; Rybenkov, V V; Duguet, M et al. (2002) The mechanism of type IA topoisomerases. Proc Natl Acad Sci U S A 99:12126-31