Koski R A, Allison D S, Worthington M, Hall B D
Nucleic Acids Res. 1982 Dec 20;10(24):8127-43. doi: 10.1093/nar/10.24.8127.
A soluble cell-free extract containing RNA polymerase III and factors essential for selective transcription of the yeast SUP4-o tRNATyr gene was prepared from Saccharomyces cerevisiae cells. An intragenic promoter for yeast RNA polymerase III was identified within the yeast tRNATyr coding sequence by testing several sup4 genes with 5'- and 3'-terminal deletions in the homologous transcription system. Thirty-four different sup4 genes with spontaneous mutations were also tested in the in vitro system. Two point mutations drastically reduced transcription initiation and two other mutations caused premature termination. These mutations have nearly identical effects on SUP4 gene transcription by Xenopus RNA polymerase III (1), which demonstrates that the essential features of RNA polymerase III transcription initiation and termination signals have been conserved throughout the course of eukaryotic evolution.
从酿酒酵母细胞中制备了一种可溶性无细胞提取物，其中含有RNA聚合酶III以及酵母SUP4-o tRNATyr基因选择性转录所必需的因子。通过在同源转录系统中测试几个具有5'和3'末端缺失的sup4基因，在酵母tRNATyr编码序列内鉴定出了酵母RNA聚合酶III的基因内启动子。还在体外系统中测试了34个具有自发突变的不同sup4基因。两个点突变极大地降低了转录起始，另外两个突变导致了提前终止。这些突变对非洲爪蟾RNA聚合酶III转录SUP4基因具有几乎相同的影响(1)，这表明RNA聚合酶III转录起始和终止信号的基本特征在真核生物进化过程中一直保守。
