Coactivators and corepressors of NF-kappaB in IkappaB alpha gene promoter.
In this study, we investigated recruitment of coactivators (SRC-1, SRC-2, and SRC-3) and corepressors (HDAC1, HDAC2, HDAC3, SMRT, and NCoR) to the IkappaB alpha gene promoter after NF-kappaB activation by tumor necrosis factor-alpha. Our data from chromatin immunoprecipitation assay suggest that coactivators and corepressors are simultaneously recruited to the promoter, and their binding to the promoter DNA is oscillated in HEK293 cells. SRC-1, SRC-2, and SRC-3 all enhanced IkappaB alpha transcription. However, the interaction of each coactivator with the promoter exhibited different patterns. After tumor necrosis factor-alpha treatment, SRC-1 signal was increased gradually, but SRC-2 signal was reduced immediately, suggesting replacement of SRC-2 by SRC-1. SRC-3 signal was increased at 30 min, reduced at 60 min, and then increased again at 120 min, suggesting an oscillation of SRC-3. The corepressors were recruited to the promoter together with the coactivators. The binding pattern suggests that the corepressor proteins formed two types of corepressor complexes, SMRT-HDAC1 and NCoR-HDAC3. The two complexes exhibited a switch at 30 and 60 min. The functions of cofactors were confirmed by gene overexpression and RNA interference-mediated gene knockdown. These data suggest that gene transactivation by the transcription factor NF-kappaB is subject to the regulation of a dynamic balance between the coactivators and corepressors. This model may represent a mechanism for integration of extracellular signals into a precise control of gene transcription.
Gao
Zhanguo
Z
Pennington Biomedical Research Center, Louisiana State University Systems, Baton Rouge, Louisiana 70808, USA.
Chiao
Paul
P
Zhang
Xia
X
Zhang
Xiaohong
X
Lazar
Mitchell A
MA
Seto
Edward
E
Young
Howard A
HA
Ye
Jianping
J
D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D047369:Chromatin Immunoprecipitation; D005786:Gene Expression Regulation; D051548:Histone Acetyltransferases; D056284:Histone Deacetylase 1; D006655:Histone Deacetylases / Q000378:metabolism; D006801:Humans; D020672:I-kappa B Proteins / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism*; D056920:Nuclear Receptor Coactivator 1; D051958:Nuclear Receptor Coactivator 2; D009991:Oscillometry; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013997:Time Factors; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D000099186:Histone Deacetylase 3
D051548:Histone Acetyltransferases; D056284:Histone Deacetylase 1; D006655:Histone Deacetylases; D020672:I-kappa B Proteins; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B; D056920:Nuclear Receptor Coactivator 1; D051958:Nuclear Receptor Coactivator 2; D012333:RNA, Messenger; D014157:Transcription Factors; D014409:Tumor Necrosis Factor-alpha; D000099186:Histone Deacetylase 3; C000606204:NFKBIA protein, human; C000606205:Nfkbia protein, mouse; C538859:NCOA1 protein, human; C538861:Ncoa1 protein, mouse; C110550:HDAC1 protein, human