Novel domains and orthologues of eukaryotic transcription elongation factors
Novel domains and orthologues of eukaryotic transcription elongation factors
复制标题
DOI：
10.1093/nar/gkf498
复制
发表时间：
2002-09-01
影响因子：
14.9
通讯作者：
Ponting, CP
中科院分区：
文献类型：
--
作者：
Ponting, CP
RNA聚合酶II穿过真核基因的通道受到核小体的阻碍，核小体是组蛋白H2 A、H2 B、H3和H4二聚体的八聚体。已知酵母酿酒酵母中的十几种因子通过染色质促进转录延伸。为了更好地理解这些因子的进化和功能，将它们的序列与已知的蛋白质、EST和DNA序列进行了比较。Elongator亚复合物组分Elp 4p和Elp 6p被证明是ATP酶的同源物，但具有对ATP水解至关重要的氨基酸取代，并且Elp 5 p的新直向同源物在人类和其他动物序列中是可检测的。酵母CP复合物中含有M24家族金属蛋白酶Spt 16 p/Cdc 68 p的可能无活性同源物和哺乳动物SSRP 1直向同源物Pob 3 p的2倍重复序列。大肠杆菌DNA指导的RNA聚合酶亚基E”显示为真核Spt 4p的直向同源物，Spt 5 p和原核NusG显示含有新的“NGN”结构域。发现Spt 6p含有与RNA酶的YqgF家族同源的结构域，尽管该结构域也可能缺乏催化活性。这些发现意味着，真核生物的转录延伸机制已获得后，他们从原核生物的分歧。
The passage of RNA polymerase II across eukaryotic genes is impeded by the nucleosome, an octamer of histones H2A, H2B, H3 and H4 dimers. More than a dozen factors in the yeast Saccharomyces cerevisiae are known to facilitate transcription elongation through chromatin. In order to better understand the evolution and function of these factors, their sequences have been compared with known protein, EST and DNA sequences. Elongator subcomplex components Elp4p and Elp6p are shown to be homologues of ATPases, yet with substitutions of amino acids critical for ATP hydrolysis, and novel orthologues of Elp5p are detectable in human, and other animal, sequences. The yeast CP complex is shown to contain a likely inactive homologue of M24 family metalloproteases in Spt16p/Cdc68p and a 2-fold repeat in Pob3p, the orthologue of mammalian SSRP1. Archaeal DNA-directed RNA polymerase subunit E" is shown to be the orthologue of eukaryotic Spt4p, and Spt5p and prokaryotic NusG are shown to contain a novel 'NGN' domain. Spt6p is found to contain a domain homologous to the YqgF family of RNases, although this domain may also lack catalytic activity. These findings imply that much of the transcription elongation machinery of eukaryotes has been acquired subsequent to their divergence from prokaryotes.