Activation domain-mediated enhancement of activator binding to chromatin in mammalian cells

被引:21
作者
Bunker, CA
Kingston, RE
机构
[1] MASSACHUSETTS GEN HOSP, DEPT MOL BIOL, BOSTON, MA 02114 USA
[2] HARVARD UNIV, SCH MED, DEPT GENET, BOSTON, MA 02115 USA
关键词
D O I
10.1073/pnas.93.20.10820
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
DNA binding by transcriptional activators is typically an obligatory step in the activation of gene expression, Activator binding and subsequent steps in transcription are repressed by genomic chromatin. Studies in vitro have suggested that overcoming this repression is an important function of some activation domains. Here we provide quantitative in vivo evidence that the activation domain of GAL4-VP16 can increase the affinity of GAL4 for its binding site on genomic DNA in mammalian cells. Moreover, the VP16 activation domain has a much greater stimulatory effect on expression from a genomic reporter gene than on a transiently transfected reporter gene, where factor binding is more permissive, We found that not all activation domains showed a greater activation potential in a genomic context, suggesting that only some activation domains can function in vivo to alleviate the repressive effects of chromatin, These data demonstrate the importance of activation domains in relieving chromatin-mediated repression in vivo and suggest that one way they function is to increase binding of the activator itself.
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页码:10820 / 10825
页数:6
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