IMPORTED TRNAS IN MITOCHONDRIA OF LEISHMANIA TARENTOLAE

线粒体基因组中完全缺乏转移RNA基因 (上环和小环DNA)，是独有的特征之一。 动质体有机体的特征。我们之前的凝胶电泳法， 氨基酰化、L和杂交研究表明， 从狼毒利什曼原虫分离的线粒体不含细胞质 污染物，但含有功能性的tRNA，大多数f似乎是 与细胞质tRNAs相同(例如，tRNAleu)，而其他一些是 独特的[tRNAmet和可能的tRNAtrp]。有人建议，即使不是大多数，也是 所有线粒体tRNA都是核DNA编码的，可能是进口的，但 这必须通过直接测序和克隆分析来证实。这个 因此，这项研究的直接目标是获得直接证据 特定的线粒体tRNAs是核起源的。这个目标可以是 如果一个核基因克隆的序列与 发现了上述线粒体tRNA序列。在这项研究中， 因此，线粒体和细胞质tRNAs的所有同种受体形式 亮氨酸、L蛋氨酸和色氨酸将被鉴定、凝胶纯化和 测序、修饰碱基确定及核基因克隆 并进行了测序。线粒体tRNA序列的存在 也会排除这些线粒体 TRNA是通过对上环或微环转录本进行RNA编辑而创建的。 从这些研究中获得的信息应提供必要的信息 确定tRNA导入和核基因机制的基础 线粒体功能的调节是发育控制的一部分 发生在这些寄生有机体中。

The complete absence of transfer RNA genes in the mitochondrial genome (maxicircle and minicircle DNA),, is one of the unique features characterizing kinetoplastid organisms. Our previous gel electrophoresis, amino acylation,l and hybridization studies have shown that, the mitochondrion isolated from Leishmania tarantulae is free of cytoplasmic contaminants but contains functional tRNAs, most f which appear to be identical with cytoplasmic tRNAs {e.g.,tRNAleu], while some other are unique [tRNAmet and possibly tRNAtrp]. It is suggested that most if not all mitochondrial tRNAs are nuclear-DNA encoded and possibly imported, but this must be confirmed by direct sequencing and cloning analyses. The immediate goal of this research, therefore, is to obtain direct evidence that specific mitochondrial tRNAs are of nuclear origin. This goal can be attained if a nuclear gene clone having the same sequence as the mitochondrial tRNA sequence in question is found. In this research, therefore, all isoacceptor forms of mitochondrial and cytoplasmic tRNAs for leucine,l methionine and tryptophan will be identified, gel-purified, and sequenced, their modified bases determined, and the nuclear gene cloning and sequencing conducted. The presence of the mitochondrial tRNA sequence in the nucleus will also rule out the possibility that these mitochondrial tRNAs are created by RNA editing from maxicircle or minicircle transcripts. The information gained from these studies should provide necessary groundwork for defining the mechanisms of tRNA import and the nuclear gene regulation of mitochondrial function as part of developmental control occurring in these parasitic organisms.