Target genes of the largest human SWI/SNF complex subunit control cell growth.
The largest subunit of the mammalian SWI/SNF-A or BAF (BRG1-associated factor) chromatin-remodelling complex is encoded by two related cDNAs hOsa1/BAF250a and hOsa2/BAF250b that are unique to the BAF complex and absent in the related PBAF (Polybromo BAF). hOsa/BAF250 has been shown to interact with transcriptional activators and bind to DNA suggesting that it acts to target the remodelling complex to chromatin. To better understand the functions of hOsa2, we established inducible stable HeLa cell lines over-expressing FLAG-hOsa2 or a derivative lacking the ARID (AT-rich interactive domain) DNA-binding domain. Immunopurification of complexes containing hOsa2 that was followed by mass spectrometry and immunoblotting demonstrated the presence of BRG1 and known BAFs, but not hOsa1 or hBRM. Deletion of the ARID did not compromise the integrity of the complex. Induction of hOsa2 expression caused impaired cell growth and accumulation of cells in the G0/G1 cell cycle phase. Elevated levels of the p53 and p21 proteins were detected in these cells while c-Myc mRNA and protein levels were found to decrease. Chromatin immunoprecipitation and reporter assays suggested that hOsa2 had a direct effect on c-myc and p21 promoter activity. Thus hOsa2 plays an important role in controlling genes regulating the cell cycle.
Department of Microbiology and NYU Cancer Institute, New York University School of Medicine, 550 First Avenue, New York, NY 10016-6481, U.S.A.
Hiroko
H
Inoue
Stavros
S
Giannakopoulos
Christopher N
CN
Parkhurst
Tatsushi
T
Matsumura
Evelyn A
EA
Kono
Takako
T
Furukawa
Naoko
N
Tanese
D049109:Cell Proliferation; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism*; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation / Q000502:physiology*; D016259:Genes, myc / Q000235:genetics / Q000502:physiology; D006367:HeLa Cells; D006801:Humans; D011401:Promoter Regions, Genetic; D021122:Protein Subunits; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism
C493956:CDKN1A protein, human; D002868:Chromosomal Proteins, Non-Histone; D050759:Cyclin-Dependent Kinase Inhibitor p21; D021122:Protein Subunits; C445179:SWI-SNF-B chromatin-remodeling complex; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53