The packaging of DNA into chromatin makes it largely inaccessible for the central nuclear processes of transcription, replication, recombination and repair. ATP-dependent chromatin remodeling motors play key roles in both increasing DNA access within chromatin as well in generating higher-order chromatin structures that promote transcriptional repression. However, the mechanisms by which chromatin remodeling motors function are largely unknown. The overall goal of this proposal is to use concepts learnt from well-studied motors such as kinesin and helicases to understand the how a major ATP- dependent chromatin-remodeling complex, human ACF functions. ACF generates evenly spaced nucleosomes to enable higher-order chromatin folding and gene silencing. Our work over the last grant period has shown that ACF functions as a dimeric motor in which each ATPase subunit takes turns engaging either side of a nucleosome. Here we will build on these discoveries to address the following questions: (1) How are the activities of the two ATPase subunits in ACF coordinated? (2) How does ACF recognize and use specific nucleosomal features in its reaction mechanism? (3) How is ACF activity regulated by the presence of adjacent nucleosomes?

Public Health Relevance

PROJECT NARRATIVE ACF complexes play crucial roles in mediating heritable gene silencing. Consistent with these roles, mutations in the components of ACF complexes are associated with severe developmental defects and specific cancers. A detailed understanding of ACF mechanism will provide insights into how its activity is regulated and how it malfunctions.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM073767-07
Application #
8137216
Study Section
Molecular Genetics A Study Section (MGA)
Program Officer
Preusch, Peter C
Project Start
2005-04-01
Project End
2014-06-30
Budget Start
2011-07-01
Budget End
2012-06-30
Support Year
7
Fiscal Year
2011
Total Cost
$366,547
Indirect Cost
Name
University of California San Francisco
Department
Biochemistry
Type
Schools of Medicine
DUNS #
094878337
City
San Francisco
State
CA
Country
United States
Zip Code
94143
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Racki, Lisa R; Naber, Nariman; Pate, Ed et al. (2014) The histone H4 tail regulates the conformation of the ATP-binding pocket in the SNF2h chromatin remodeling enzyme. J Mol Biol 426:2034-44

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