RNA polymerase II subunit RPB3 is an essential component of the mRNA transcription apparatus
RNA polymerase II subunit RPB3 is an essential component of the mRNA transcription apparatus
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DOI：
10.1128/mcb.9.12.5387-5394.1989
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发表时间：
1989-12
影响因子：
5.3
通讯作者：
P. Kolodziej;R. Young
中科院分区：
文献类型：
--
作者：
P. Kolodziej;R. Young
为了提高我们对RNA聚合酶II的理解，通过使用抗体探针从λ gt 11 DNA文库中分离编码其第三大亚基RPB 3的基因。RPB 3 DNA序列预测了一个318个氨基酸的蛋白质，其序列部分通过凝胶纯化的RNA聚合酶II亚基的微序列分析得到证实。RPB 3是一个必需的单拷贝基因，与IX号染色体上的HIS 6紧密连锁。分离到一株RPB 3温度敏感突变株，该突变株在限制性温度下生长3 ~ 4代后停止生长。当突变体转移到限制性温度时，RNA聚合酶II不再能够组装，先前组装的功能酶被耗尽，mRNA水平因此降低。这些结果表明，RPB 3是mRNA转录装置的重要组成部分。最后，RPB 3蛋白在序列和长度上与RPC 5相似，RPC 5是RNA聚合酶I和III共有的亚基，这表明这些亚基可能在RNA聚合酶I、II和III中发挥相似的作用。
To improve our understanding of RNA polymerase II, the gene that encodes its third-largest subunit, RPB3, was isolated from a lambda gt11 DNA library by using antibody probes. The RPB3 DNA sequence predicts a 318-amino-acid protein whose sequence was confirmed, in part, by microsequence analysis of the gel-purified RNA polymerase II subunit. RPB3 was found to be an essential single-copy gene that is tightly linked to HIS6 on chromosome IX. An RPB3 temperature-sensitive mutant that arrested growth after three to four generations at the restrictive temperature was isolated. When the mutant was shifted to the restrictive temperature, RNA polymerase II could no longer assemble, previously assembled functional enzyme was depleted, and mRNA levels were consequently reduced. These results demonstrate that RPB3 is an essential component of the mRNA transcription apparatus. Finally, the RPB3 protein is similar in sequence and length to RPC5, a subunit common to RNA polymerases I and III, suggesting that these subunits may play similar roles in RNA polymerases I, II, and III.