A mammalian bromodomain protein, Brd4, interacts with replication factor C and inhibits progression to S phase Journal Article


Authors: Maruyama, T.; Farina, A.; Dey, A.; Cheong, J.; Bermudez, V. P.; Tamura, T.; Sciortino, S.; Shuman, J.; Hurwitz, J.; Ozato, K.
Article Title: A mammalian bromodomain protein, Brd4, interacts with replication factor C and inhibits progression to S phase
Abstract: Brd4 belongs to the BET family of nuclear proteins that carry two bromodomains implicated in the interaction with chromatin. Expression of Brd4 correlates with cell growth and is induced during early G, upon mitogenic stimuli. In the present study, we investigated the role of Brd4 in cell growth regulation. We found that ectopic expression of Brd4 in NIH 3T3 and HeLa cells inhibits cell cycle progression from G, to S. Coimmunoprecipitation experiments showed that endogenous and transfected Brd4 interacts with replication factor C (RFC), the conserved five-subunit complex essential for DNA replication. In vitro analysis showed that Brd4 binds directly to the largest subunit, RFC-140, thereby interacting with the entire RFC. In line with the inhibitory activity seen in vivo, recombinant Brd4 inhibited RFC-dependent DNA elongation reactions in vitro. Analysis of Brd4 deletion mutants indicated that both the interaction with RFC-140 and the inhibition of entry into S phase are dependent on the second bromodomain of Brd4. Lastly, supporting the functional importance of this interaction, it was found that cotransfection with RFC-140 reduced the growth-inhibitory effect of Brd4. Taken as a whole, the present study suggests that Brd4 regulates cell cycle progression in part by interacting with RFC.
Keywords: identification; complex-formation; subunit; dna-replication; atpase activity; large; eukaryotic cells; cell nuclear antigen; effect homeotic gene; drosophila-fsh; ring3 gene
Journal Title: Molecular and Cellular Biology
Volume: 22
Issue: 18
ISSN: 0270-7306
Publisher: American Society for Microbiology  
Date Published: 2002-09-01
Start Page: 6509
End Page: 6520
Language: English
ACCESSION: WOS:000177642900018
DOI: 10.1128/mcb.22.18.6509-6520.2002
PROVIDER: wos
PMCID: PMC135621
PUBMED: 12192049
Notes: Article -- Source: Wos
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  1. Jerard Hurwitz
    206 Hurwitz