TY - JOUR
T1 - E2F-mediated growth regulation requires transcription factor cooperation
AU - Van Ginkel, Paul R.
AU - Hsiao, Kuang Ming
AU - Schjerven, Hilde
AU - Farnham, Peggy J.
PY - 1997/7/18
Y1 - 1997/7/18
N2 - Previous studies have indicated that the presence of an E2F site is not sufficient for G1/S phase transcriptional regulation. For example, the E2F sites in the E2F1 promoter are necessary, but not sufficient, to mediate differential promoter activity in G0 and S phase. We have now utilized the E2F1 minimal promoter to test several hypotheses that could account for these observations. To test the hypothesis that G1/S phase regulation is achieved via E2F-mediated repression of a strong promoter, a variety of transactivation domains were brought to the E2F1 minimal promoter. Although many of these factors caused increased promoter activity, growth regulation was not observed, suggesting that a general repression model is incorrect. However, constructs having CCAAT or YY1 sites or certain GC boxes cloned upstream of the E2F1 minimal promoter displayed E2F site-dependent regulation. Further analysis of the promoter activity suggested that E2F requires cooperation with another factor to activate transcription in S phase. However, we found that the requirement for E2F to cooperate with additional factors to achieve growth regulation could be relieved by bringing the E2F1 activation domain to the promoter via a Ga14 DNA binding domain. Our results suggest a model that explains why some, but not all, promoters that contain E2F sites display growth regulation.
AB - Previous studies have indicated that the presence of an E2F site is not sufficient for G1/S phase transcriptional regulation. For example, the E2F sites in the E2F1 promoter are necessary, but not sufficient, to mediate differential promoter activity in G0 and S phase. We have now utilized the E2F1 minimal promoter to test several hypotheses that could account for these observations. To test the hypothesis that G1/S phase regulation is achieved via E2F-mediated repression of a strong promoter, a variety of transactivation domains were brought to the E2F1 minimal promoter. Although many of these factors caused increased promoter activity, growth regulation was not observed, suggesting that a general repression model is incorrect. However, constructs having CCAAT or YY1 sites or certain GC boxes cloned upstream of the E2F1 minimal promoter displayed E2F site-dependent regulation. Further analysis of the promoter activity suggested that E2F requires cooperation with another factor to activate transcription in S phase. However, we found that the requirement for E2F to cooperate with additional factors to achieve growth regulation could be relieved by bringing the E2F1 activation domain to the promoter via a Ga14 DNA binding domain. Our results suggest a model that explains why some, but not all, promoters that contain E2F sites display growth regulation.
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U2 - 10.1074/jbc.272.29.18367
DO - 10.1074/jbc.272.29.18367
M3 - Article
C2 - 9218478
AN - SCOPUS:0030789435
VL - 272
SP - 18367
EP - 18374
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 29
ER -