Béjà O, Ullu E, Michaeli S
Department of Membrane Research and Biophysics, Weizmann Institute of Science, Rehovot, Israel.
Mol Biochem Parasitol. 1993 Feb;57(2):223-9. doi: 10.1016/0166-6851(93)90198-7.
During the purification of Trypanosoma brucei 7SL RNA, we detected a small RNA, 76 nucleotide-long (sRNA-76), that copurified with the 7SL RNP through several different separation steps. In this study, a partial RNA sequence of sRNA-76 was obtained and a complementary oligonucleotide to the RNA sequence was used to clone the corresponding gene. sRNA-76 is very similar to a tRNA molecule and is encoded by a single copy gene. The gene is located next to a tRNA(Val) which has 75.3% homology to T. brucei tRNA(Val) that exists in a different chromosomal locus. The highest homology of sRNA-76 is to mouse and rat tRNA(Asp) (69%), to mouse tRNA(Gly) (68.1%) and to yeast suppressor tRNA(Gly) (69.5%). However, sRNA-76 is neither a tRNA(Asp) nor a tRNA(Gly), since it has a Leu anticodon. In addition, sRNA-76 deviates from the canonical tRNA structure in 3 positions. A potential for base pairing between sRNA-76 and 7SL RNA was found in the 100 nt region of 7SL RNA, which is a highly conserved region in all 7SL RNAs.
在布氏锥虫7SL RNA的纯化过程中，我们检测到一种小RNA，长度为76个核苷酸（sRNA-76），它在几个不同的分离步骤中与7SL核糖核蛋白体（RNP）共同纯化。在本研究中，获得了sRNA-76的部分RNA序列，并使用与该RNA序列互补的寡核苷酸克隆了相应基因。sRNA-76与tRNA分子非常相似，由单拷贝基因编码。该基因位于一个tRNA（Val）旁边，与位于不同染色体位点的布氏锥虫tRNA（Val）具有75.3%的同源性。sRNA-76与小鼠和大鼠的tRNA（Asp）（69%）、小鼠的tRNA（Gly）（68.1%）以及酵母抑制性tRNA（Gly）（69.5%）的同源性最高。然而，sRNA-76既不是tRNA（Asp）也不是tRNA（Gly），因为它具有亮氨酸反密码子。此外，sRNA-76在3个位置上偏离了典型的tRNA结构。在7SL RNA的100 nt区域发现了sRNA-76与7SL RNA之间存在碱基配对的可能性，该区域在所有7SL RNA中都是高度保守的区域。
