In vivo requirement of the RNA polymerase II elongation factor elongin A for proper gene expression and development
In vivo requirement of the RNA polymerase II elongation factor elongin A for proper gene expression and development
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DOI：
10.1128/mcb.24.22.9911-9919.2004
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发表时间：
2004-11-01
影响因子：
5.3
通讯作者：
Shilatifard, A
中科院分区：
文献类型：
--
作者：
Gerber, M;Eissenberg, JC;Shilatifard, A
已经从高等真核生物中纯化了许多提高RNA聚合酶II（Pol II）催化mRNA合成速率的转录因子。其中包括ELL家族、DSIF和异源三聚体延伸蛋白复合物。延伸蛋白A是延伸蛋白复合物的最大亚基，是转录活性亚基，而较小的延伸蛋白B和C亚基似乎充当调节亚基。虽然关于延伸蛋白A和这类延伸因子的其他成员的体外性质已知很多，但这些蛋白质的生理作用在很大程度上仍然不清楚。为了阐明elongin A在体内的功能，我们对其果蝇同源物（dEloA）进行了表征。dEloA与果蝇多线染色体内的转录活性puff位点相关，并表现出许多与Pol II相关延伸因子一致的预期生化和细胞学特性。RNA干扰介导的dEloA耗竭表明，延长蛋白A是一个必要的因素，需要适当的变态。与这一观察结果一致，dEloA表达在发育的幼虫阶段达到峰值，表明该因子对于在这些阶段期间适当调节发育事件可能是重要的。在体内模型系统中发现延伸蛋白A的作用，定义了RNA聚合酶II延伸机制在调节基因表达中所起的新作用，这是正常发育所必需的。
A number of transcription factors that increase the catalytic rate of mRNA synthesis by RNA polymerase II (Pol II) have been purified from higher eukaryotes. Among these are the ELL family, DSIF, and the heterotrimeric elongin complex. Elongin A, the largest subunit of the elongin complex, is the transcriptionally active subunit, while the smaller elongin B and C subunits appear to act as regulatory subunits. While much is known about the in vitro properties of elongin A and other members of this class of elongation factors, the physiological role(s) of these proteins remain largely unclear. To elucidate in vivo functions of elongin A, we have characterized its Drosophila homologue (dEloA). dEloA associates with transcriptionally active puff sites within Drosophila polytene chromosomes and exhibits many of the expected biochemical and cytological properties consistent with a Pol II-associated elongation factor. RNA interference-mediated depletion of dEloA demonstrated that elongin A is an essential factor that is required for proper metamorphosis. Consistent with this observation, dEloA expression peaks during the larval stages of development, suggesting that this factor may be important for proper regulation of developmental events during these stages. The discovery of the role of elongin A in an in vivo model system defines the novel contribution played by RNA polymerase II elongation machinery in regulation of gene expression that is required for proper development.