An IFN regulatory factor-2 DNA-binding domain dominant negative mutant exhibits altered cell growth and gene expression.
In order to study interferon regulatory factor (IRF) family mediation of cell growth regulation, we established U937 cell lines stably transfected with a truncated form of IRF-2 lacking the transcriptional repressor domain. The truncated IRF-2 contained the DNA binding domain (DBD) and bound the ISRE. Phenotypically, the IRF-2 DBD transfectants exhibited reduced cell growth, altered morphology and increased cell death. Consistent with alterations in growth characteristics, the IRF-2 DBD transfectants constitutively expressed higher levels of the cyclin dependent kinase inhibitor p21WAF1/Cip1 than did control clones. The level of p21WAF1/Cip1 expression was positively correlated with the level of DBD expressed, as well as with the level of growth inhibition in these clones. DBD expression also correlated with expression of other members of the growth regulatory complex, cyclin dependent kinase 2 and cyclin A, but not proliferating cell nuclear antigen. These results imply active repression by IRF-2 to keep p21WAF1/Cip1 transcriptionally silent.
Rubinstein
Y R
YR
Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, MD 20742, USA.
Driggers
P H
PH
Ogryzko
V V
VV
Thornton
A M
AM
Ozato
K
K
Pontzer
C H
CH
D001665:Binding Sites / Q000235:genetics; D002455:Cell Division / Q000235:genetics; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000096:biosynthesis / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic; D005799:Genes, Dominant; D006801:Humans; D050836:Interferon Regulatory Factor-2; D007372:Interferons / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D012097:Repressor Proteins; D020218:Response Elements; D014157:Transcription Factors; D014162:Transfection; D020298:U937 Cells
C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D004268:DNA-Binding Proteins; C494229:IRF2 protein, human; D050836:Interferon Regulatory Factor-2; D012097:Repressor Proteins; D014157:Transcription Factors; D007372:Interferons