Endoh H, Okada N
Proc Natl Acad Sci U S A. 1986 Jan;83(2):251-5. doi: 10.1073/pnas.83.2.251.
Total DNAs from various animals were transcribed in vitro in a HeLa cell extract, and it was found that one to several discrete RNAs were transcribed by RNA polymerase III. With tortoise (Geoclemys reevessi) and newt (Cynops pyrrhogaster), distinct 6.5S and 8S RNAs were transcribed from these respective DNAs. Representative phage clones carrying the 6.5S and 8S RNA genes were isolated from genomic libraries of these animals, and the sequences of these genes were determined. The 5' parts of highly repetitive and transcribable sequences of tortoise and newt were found to have close resemblance to tRNALys1 (rabbit) gene (78% homology) and a tRNAGlu (Drosophila) gene (74% homology, not counting the aminoacyl stem region), respectively. The homologies extended to secondary structures, homologous nucleotides being located on similar secondary structures. It is proposed that many, if not all, highly repetitive and transcribable sequences detected by total DNA transcription have specific tRNA genes as their progenitors.
从各种动物中提取的总DNA在HeLa细胞提取物中进行体外转录，结果发现RNA聚合酶III转录出了一到几种离散的RNA。对于乌龟（中华草龟）和蝾螈（东方蝾螈），分别从它们各自的DNA转录出了独特的6.5S和8S RNA。从这些动物的基因组文库中分离出携带6.5S和8S RNA基因的代表性噬菌体克隆，并测定了这些基因的序列。发现乌龟和蝾螈高度重复且可转录序列的5'部分分别与tRNALys1（兔）基因（78%同源性）和tRNAGlu（果蝇）基因（74%同源性，不包括氨酰基茎区）有密切相似性。这种同源性延伸到二级结构，同源核苷酸位于相似的二级结构上。有人提出，通过总DNA转录检测到的许多（如果不是全部）高度重复且可转录的序列都以特定的tRNA基因为其祖先。
