双翅目5S RNA基因中保守的5'侧翼同源性，其可作用于“A”型DNA。
Conserved 5' flank homologies in dipteran 5S RNA genes that would function on 'A' form DNA.
作者信息
Rubacha A, Sumner W, Richter L, Beckingham K
出版信息
Nucleic Acids Res. 1984 Nov 12;12(21):8193-207. doi: 10.1093/nar/12.21.8193.
We have sequenced the 480 base pair (bp) repeating unit of the 5S RNA genes of the Dipteran fly Calliphora erythrocephala and compared this sequence to the three known 5S RNA gene sequences from the Dipteran Genus Drosophila (1,2). A striking series of five perfectly conserved homologies identically positioned within the 5' flanks of all four Dipteran 5S RNA coding regions has thus been identified. The spacing (12-13 bp) between all of these homologies is typical of A form rather than B form DNA. Given that the eukaryotic 5S RNA gene specific initiation factor TFIIIA (3) is a DNA unwinding protein (4), a role for these Dipteran 5' flank homologies in initiation site selection on 5S RNA genes transiently unwound for transcription is suggested. One of the Dipteran homology blocks is highly conserved in sequence and position in all but one of the eukaryotic 5S RNA gene sequences known to date (17/18 genes). Its sequence (consensus: TATAAG) and position (average center: -26 bp) are highly reminiscent of the polymerase II gene 'TATA' box (5).
我们已对双翅目红头丽蝇5S RNA基因的480个碱基对（bp）重复单元进行了测序，并将此序列与双翅目果蝇属的三个已知5S RNA基因序列进行了比较（参考文献1,2）。由此确定了一系列引人注目的五个完全保守的同源序列，它们在所有四个双翅目5S RNA编码区的5'侧翼内位置相同。所有这些同源序列之间的间距（12 - 13 bp）是典型的A型而非B型DNA。鉴于真核生物5S RNA基因特异性起始因子TFIIIA（参考文献3）是一种DNA解旋蛋白（参考文献4），因此推测这些双翅目5'侧翼同源序列在转录时暂时解旋的5S RNA基因起始位点选择中发挥作用。在迄今为止已知的所有真核生物5S RNA基因序列（17/18个基因）中，除一个之外几乎所有序列的双翅目同源序列块之一在序列和位置上都高度保守。其序列（共有序列：TATAAG）和位置（平均中心：-26 bp）与聚合酶II基因的“TATA”框（参考文献5）极为相似。
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