Dente L, Fasano O, Costanzo F, Traboni C, Ciliberto G, Cortese R
EMBO J. 1982;1(7):817-20. doi: 10.1002/j.1460-2075.1982.tb01253.x.
Eukaryotic tDNA promoters are composed of two essential regions contained within the coding sequence (Box A and Box B). Due to the highly conserved structure of prokaryotic and eukaryotic tRNA, most prokaryotic tRNA genes are expected to be active templates in eukaryotic transcriptional systems. In this paper we show that Escherichia coli tDNATyr is not transcribed in the nucleus of Xenopus laevis oocytes. By in vitro construction of hybrid molecules between inactive prokaryotic tDNATyr from E. coli, and active eukaryotic tDNAPro from Caenorhabditis elegans, we show that tDNATyr can be made into an active gene if its first third, including the Box A region, is replaced by that of the eukaryotic tDNA . These results suggest that an improper Box A sequence is responsible for the inactivity of the E. coli tRNATyr gene, and argue against the role of secondary and tertiary DNA conformations in RNA polymerase III transcription.
真核生物的tDNA启动子由编码序列中包含的两个必需区域（A框和B框）组成。由于原核生物和真核生物tRNA的结构高度保守，大多数原核生物tRNA基因有望成为真核转录系统中的活性模板。在本文中，我们表明大肠杆菌tDNATyr在非洲爪蟾卵母细胞核中不转录。通过体外构建来自大肠杆菌的无活性原核tDNATyr与来自秀丽隐杆线虫的活性真核tDNAPro之间的杂交分子，我们表明，如果将其前三分之一（包括A框区域）替换为真核tDNA的相应部分，tDNATyr可以成为一个活性基因。这些结果表明，A框序列不当是大肠杆菌tRNATyr基因无活性的原因，并反对二级和三级DNA构象在RNA聚合酶III转录中的作用。
