PURIFICATION, CLONING, AND CHARACTERIZATION OF A HUMAN COACTIVATOR, PC4, THAT MEDIATES TRANSCRIPTIONAL ACTIVATION OF CLASS-II GENES
PURIFICATION, CLONING, AND CHARACTERIZATION OF A HUMAN COACTIVATOR, PC4, THAT MEDIATES TRANSCRIPTIONAL ACTIVATION OF CLASS-II GENES
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DOI：
10.1016/0092-8674(94)90428-6
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发表时间：
1994-08-12
期刊：
影响因子：
64.5
通讯作者：
ROEDER, RG
中科院分区：
文献类型：
--
作者：
GE, H;ROEDER, RG
哺乳动物细胞中的激活子依赖性转录除了TFIID中存在的那些外，还需要上游刺激活性（USA）衍生的辅因子。一种新的正辅因子（PC 4）纯化的人美国部分影响显着增强（高达85倍）的GAL 4-AH依赖性转录与TFIID和其他一般因素。分离相应的cDNA鉴定PC 4为127个残基的单链DNA结合蛋白，在N-末端附近具有富含丝氨酸的区域。重组PC 4在功能上等同于原生PC 4，并且这两种蛋白质通过融合到GAL 4的DNA结合结构域的不同激活结构域显著增强激活。重组PC 4与游离或DNA结合的VP 16活化结构域和游离或DNA结合的TFIIA-TBP复合物（但不与单独的Tap）独立地相互作用。这些结果表明，PC 4是一个通用的辅激活因子，与TAF合作发挥作用，并介导上游激活因子和一般转录机制之间的功能相互作用。
Activator-dependent transcription in mammalian cells requires upstream stimulatory activity (USA)-derived cofactors in addition to those present in TFIID. A novel positive cofactor (PC4) purified from the human USA fraction effected a marked enhancement (up to 85-fold) of GAL4-AH-dependent transcription in conjunction with TFIID and other general factors. Isolation of a corresponding cDNA identified PC4 as a 127 residue single-stranded DNA-binding protein with serine-rich regions near the N-terminus. Recombinant PC4 was functionally equivalent to native PC4, and both proteins markedly enhanced activation by diverse activation domains fused to the DNA-binding domain of GAL4. Recombinant PC4 interacted independently both with free or DNA-bound VP16 activation domains and with free or DNA-bound TFIIA-TBP complexes (but not with Tap alone). These results indicate that PC4 is a general coactivator that functions cooperatively with TAFs and mediates functional interactions between upstream activators and the general transcriptional machinery.