IMPORTED TRNAS IN MITOCHONDRIA OF LEISHMANIA TARENTOLAE

线粒体基因组中完全不存在转运RNA基因 （大环和小环DNA），是其独特的特征之一， 描述动质体生物的特征。 我们之前的凝胶电泳， 氨基酰化和杂交研究表明， 从狼蛛利什曼原虫中分离出的嗜热单胞菌， 污染物，但含有功能性的tRNA，大多数似乎是 与细胞质tRNA相同（例如，而另一些人， tRNAmet和可能的tRNAtrp。 有人建议，如果没有， 所有的线粒体tRNA都是核DNA编码的，可能是输入的，但 这必须通过直接测序和克隆分析来证实。 的 因此，这项研究的直接目标是获得直接证据， 特定的线粒体tRNA是核起源的。 这个目标可以 如果一个核基因克隆具有相同的序列， 线粒体tRNA序列的问题。在这项研究中， 因此，线粒体和细胞质tRNA的所有同种受体形式， 亮氨酸、L-甲硫氨酸和色氨酸将被鉴定，凝胶纯化， 测序，确定其修饰碱基，并克隆核基因 并进行测序。 线粒体tRNA序列的存在 也将排除这些线粒体 tRNA是由大环或小环转录物通过RNA编辑产生的。 从这些研究中获得的信息应该提供必要的信息。 定义tRNA输入和核基因的机制的基础 线粒体功能的调节作为发育控制的一部分 发生在这些寄生生物体中。

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.