Previous studies have indicated 'hat t lie presence of an F2F site- is no MI[ iicient for (/S-phase transcription] régulai ion. For example, the K2F site.-, in the K2F1 promoter are necessary, hut not sufficient. to mediate difTeren liai promoter activity in (10 and S pha.>e. We have noed the F2FI minimal promoter to test several hypotheses that could account for these oh sorvatioris. To test the hypothesis that Cl/S-phase regulation is achieved via F2F-rnediatod repression of a strong promote, a variety of transactivation domains were brought to the K2K1 niinirnal promoter in transient transfeci ion assays. 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 (VAAT or YY1 sites or certain G(" boxes cloned upstream of the K2F1 minima promoter displayed K2F site-dependent regulation. Further analysis of the promoter activity suggested thai E2F requires cooperation with another factor to activate transcription in S phase. We next wished to define whether the DNA binding or transactivation properties of E2F determined the requirement for transcription factor cooperation. We found that the requirement for K2F to cooperate with addi tional factors to achieve growth regulation could be relieved by bringing the F2F1 activation domain to the promoter via a different DNA binding domainSupported by CA096N1. CA-J.V.MO and f'A()717.->.
|Original language||English (US)|
|State||Published - 1997|
ASJC Scopus subject areas
- Agricultural and Biological Sciences (miscellaneous)
- Biochemistry, Genetics and Molecular Biology(all)
- Cell Biology