DeFranco D, Schmidt O, Söll D
Proc Natl Acad Sci U S A. 1980 Jun;77(6):3365-8. doi: 10.1073/pnas.77.6.3365.
Two Drosophila tRNALys genes with identical coding sequences were shown to transcribe with very different efficiences in nuclear extracts from Xenopus oocytes. The use of recombinant plasmids in which the 5'-flanking sequences of these genes were either "switched" or replaced by defined pBR322 sequences revealed two control regions for tRNA gene transcription. An internal control region comprising the mature tRNA coding sequence (and possibly its 3'-flanking sequences) is sufficient for transcription initiation, and an external control region comprising the 5'-flanking sequences represses this transcription. All transcripts have short leader sequences. Altered precursor tRNAs transcribed from truncated tRNALys genes (missing a single base pair in the acceptor stem) are not processed well in vitro.
两个编码序列相同的果蝇赖氨酸转运RNA（tRNALys）基因，在非洲爪蟾卵母细胞核提取物中的转录效率差异很大。使用重组质粒，其中这些基因的5'侧翼序列要么“互换”，要么被确定的pBR322序列取代，这揭示了tRNA基因转录的两个控制区域。一个包含成熟tRNA编码序列（可能还有其3'侧翼序列）的内部控制区域足以启动转录，而一个包含5'侧翼序列的外部控制区域则会抑制这种转录。所有转录本都有短的前导序列。从截短的tRNALys基因（受体茎中缺失一个碱基对）转录而来的前体tRNA在体外加工效果不佳。
