A non-canonical multisubunit RNA polymerase encoded by a giant bacteriophage.
A non-canonical multisubunit RNA polymerase encoded by a giant bacteriophage.
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DOI：
10.1093/nar/gkv1095
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发表时间：
2015-12-02
影响因子：
14.9
通讯作者：
Minakhin L
中科院分区：
文献类型：
--
作者：
Yakunina M;Artamonova T;Borukhov S;Makarova KS;Severinov K;Minakhin L
巨噬菌体phiKZ感染铜绿假单胞菌对宿主RNA聚合酶（RNAP）抑制剂利福平具有耐药性。phiKZ编码两组多肽，这两组多肽与细胞多亚基rnap的两个最大亚基片段有远亲关系。其中一组多肽由中间噬菌体基因编码，存在于phiKZ病毒粒子中。第二组多肽由早期噬菌体基因编码，不存在于病毒粒子中。在这里，我们报道了从phikz感染细胞中分离出一个5亚基RNAP。该酶的四个亚基是非病毒粒子组的细胞RNAP亚基同源物；第五个亚基是一种功能未知的蛋白质。在体外，该复合物以利福平耐药的方式从晚期phiKZ启动子启动转录。因此，该酶是一种非病毒粒子phiKZ RNAP，负责晚期噬菌体基因的转录。phiKZ RNAP缺乏真核、古菌和细菌RNAP特有的可识别的组装和启动子特异性亚基/因子，因此为这类重要酶的机制、调控和进化的比较分析提供了独特的模型。
The infection of Pseudomonas aeruginosa by the giant bacteriophage phiKZ is resistant to host RNA polymerase (RNAP) inhibitor rifampicin. phiKZ encodes two sets of polypeptides that are distantly related to fragments of the two largest subunits of cellular multisubunit RNAPs. Polypeptides of one set are encoded by middle phage genes and are found in the phiKZ virions. Polypeptides of the second set are encoded by early phage genes and are absent from virions. Here, we report isolation of a five-subunit RNAP from phiKZ-infected cells. Four subunits of this enzyme are cellular RNAP subunits homologs of the non-virion set; the fifth subunit is a protein of unknown function. In vitro, this complex initiates transcription from late phiKZ promoters in rifampicin-resistant manner. Thus, this enzyme is a non-virion phiKZ RNAP responsible for transcription of late phage genes. The phiKZ RNAP lacks identifiable assembly and promoter specificity subunits/factors characteristic for eukaryal, archaeal and bacterial RNAPs and thus provides a unique model for comparative analysis of the mechanism, regulation and evolution of this important class of enzymes.