Our group has continued studies of chromatin structure and regulation of gene expression. In the past year we have used the RNAi technique to validate candidates from two-hybrid screens for regulators of the Drosophila Heat Shock Transcription Factor (HSF). We found that the molecular chaperones DROJ1 and HSP70 cooperate to repress the activity of HSF. Depletion of both chaperones from SL2 cells leads to full induction of HSF activity under nonstress conditions. These findings provide strong support for the feedback inhibition model for heat shock regulation. We have also completed the expression and purification of all four subunits of the Drosophila Nucleosome Remodeling Factor (NURF) in a baculovirus expression system, and found that the recombinant proteins associate to form a complex with specific activity equal to native NURF. We are continuing biochemical and genetic studies of the NURF subunits to elucidate the mechanism and physiological functions of ATP-dependent nucleosome mobility. To study other chromatin remodeling proteins, we purified a new chromatin remodeling complex from Saccharomyces cerevisiae (the INO80 complex) composed of ~12 components that is implicated in transcription and DNA damage repair.

Agency
National Institute of Health (NIH)
Institute
Division of Basic Sciences - NCI (NCI)
Type
Intramural Research (Z01)
Project #
1Z01BC005263-19
Application #
6433006
Study Section
(LMCB)
Project Start
Project End
Budget Start
Budget End
Support Year
19
Fiscal Year
2000
Total Cost
Indirect Cost
Name
Basic Sciences
Department
Type
DUNS #
City
State
Country
United States
Zip Code
Kwon, So Yeon; Xiao, Hua; Wu, Carl et al. (2009) Alternative splicing of NURF301 generates distinct NURF chromatin remodeling complexes with altered modified histone binding specificities. PLoS Genet 5:e1000574
Wu, Wei-Hua; Wu, Chwen-Huey; Ladurner, Andreas et al. (2009) N terminus of Swr1 binds to histone H2AZ and provides a platform for subunit assembly in the chromatin remodeling complex. J Biol Chem 284:6200-7
Luk, Ed; Vu, Ngoc-Diep; Patteson, Kem et al. (2007) Chz1, a nuclear chaperone for histone H2AZ. Mol Cell 25:357-68
Mizuguchi, Gaku; Xiao, Hua; Wisniewski, Jan et al. (2007) Nonhistone Scm3 and histones CenH3-H4 assemble the core of centromere-specific nucleosomes. Cell 129:1153-64
Schwanbeck, Ralf; Xiao, Hua; Wu, Carl (2004) Spatial contacts and nucleosome step movements induced by the NURF chromatin remodeling complex. J Biol Chem 279:39933-41
Mizuguchi, Gaku; Shen, Xuetong; Landry, Joe et al. (2004) ATP-driven exchange of histone H2AZ variant catalyzed by SWR1 chromatin remodeling complex. Science 303:343-8
Shen, Xuetong; Xiao, Hua; Ranallo, Ryan et al. (2003) Modulation of ATP-dependent chromatin-remodeling complexes by inositol polyphosphates. Science 299:112-4
Shen, Xuetong; Ranallo, Ryan; Choi, Eugene et al. (2003) Involvement of actin-related proteins in ATP-dependent chromatin remodeling. Mol Cell 12:147-55