Massive gene decay in the leprosy bacillus
Massive gene decay in the leprosy bacillus
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DOI：
10.1038/35059006
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发表时间：
2001-02-22
期刊：
影响因子：
64.8
通讯作者：
Barrell, BG
中科院分区：
文献类型：
--
作者：
Cole, ST;Eiglmeier, K;Barrell, BG
麻风病是一种慢性人类神经系统疾病，由专性细胞内病原体麻风分枝杆菌感染引起，它是结核杆菌的近亲。麻风分枝杆菌是所有已知细菌中加倍时间最长的，并且在实验室培养的每一次努力都遭到挫败。比较犰狳衍生的印度麻风杆菌分离物的3.27兆碱基（Mb）基因组序列与结核分枝杆菌（4.41兆碱基）基因组序列，可以清楚地解释这些特性，并揭示了还原进化的一个极端案例。不到一半的基因组包含功能基因，但假基因，在结核分枝杆菌中有完整的对应基因，比比皆是。基因组缩小和目前的镶嵌排列似乎是分散的重复序列之间广泛的重组事件的结果。基因的缺失和衰变已经消除了许多重要的代谢活动，包括铁载体的产生，部分氧化和大部分的嗜氧和厌氧呼吸链，以及许多分解代谢系统及其调控回路。
Leprosy, a chronic human neurological disease, results from infection with the obligate intracellular pathogen Mycobacterium leprae, a close relative of the tubercle bacillus. Mycobacterium leprae has the longest doubling time of all known bacteria and has thwarted every effort at culture in the laboratory. Comparing the 3.27-megabase (Mb) genome sequence of an armadillo-derived Indian isolate of the leprosy bacillus with that of Mycobacterium tuberculosis (4.41 Mb) provides clear explanations for these properties and reveals an extreme case of reductive evolution. Less than half of the genome contains functional genes but pseudogenes, with intact counterparts in M. tuberculosis, abound. Genome downsizing and the current mosaic arrangement appear to have resulted from extensive recombination events between dispersed repetitive sequences. Gene deletion and decay have eliminated many important metabolic activities including siderophore production, part of the oxidative and most of the microaerophilic and anaerobic respiratory chains, and numerous catabolic systems and their regulatory circuits.