Andersson S G, Eriksson A S, Näslund A K, Andersen M S, Kurland C G
Department of Molecular Biology, Uppsala University, Sweden.
Microb Comp Genomics. 1996;1(4):293-315.
We describe here the first general survey of the genomic content and the coding capacity of the 1.1 Mb genome of Rickettsia prowazekii based on an analysis of a total of 200 kb of unique sequence data collected in a random manner. Based on nucleotide distribution profiles, we estimate that the R. prowazekii genome may have a coding density of 60%-70% and that it may contain a total of circa 800 genes. Here, we have tentatively identified and classified 173 of these genes. Our analysis suggests that the R. prowazekii genome is a highly derived, reduced genome that has lost many genes involved in amino acid biosynthetic pathways and regulatory functions. Furthermore, the R. prowazekii genome seems to lack glycolytic genes, but it does contain genes encoding components of the tricarboxylic acid cycle as well as of the electron transport system. We have also encountered a family of homologous genes coding for ATP/ADP translocases, as observed in several mitochondrial genomes. We relate these findings to previous phylogenetic studies that suggest that Rickettsia and mitochondria share a common ancestor.
我们在此描述了基于对随机收集的总共200 kb独特序列数据的分析，对普氏立克次氏体1.1 Mb基因组的基因组内容和编码能力进行的首次全面调查。根据核苷酸分布图谱，我们估计普氏立克次氏体基因组的编码密度可能为60%-70%，并且总共可能包含约800个基因。在此，我们初步鉴定并分类了其中的173个基因。我们的分析表明，普氏立克次氏体基因组是一个高度衍生、简化的基因组，已经失去了许多参与氨基酸生物合成途径和调节功能的基因。此外，普氏立克次氏体基因组似乎缺乏糖酵解基因，但它确实包含编码三羧酸循环以及电子传递系统成分的基因。我们还遇到了一个编码ATP/ADP转位酶的同源基因家族，这在几个线粒体基因组中也有观察到。我们将这些发现与之前的系统发育研究联系起来，这些研究表明立克次氏体和线粒体有共同的祖先。
