McKean P G, Keen J K, Smith D F, Benson F E
Department of Biochemistry, Imperial College of Science, Technology and Medicine, South Kensington, SW7 2AZ, London, UK.
Mol Biochem Parasitol. 2001 Jul;115(2):209-16. doi: 10.1016/s0166-6851(01)00288-2.
The RAD51 gene is a homologue of Escherichia coli recA which plays a central role in homologous recombination and DNA repair. This paper describes the identification of the RAD51 gene from the trypanosomatid parasite Leishmania major. The LmRAD51 gene codes for a 377 amino acid polypeptide with a predicted molecular mass of 41259 Da that is highly homologous to the Rad51 family of proteins. Recombinant L. major Rad51 protein (LmRad51) was over-expressed in a bacterial expression system, purified to homogeneity and shown to bind DNA and exhibit DNA-stimulated ATPase activity, consistent with previously reported biochemical characteristics of Rad51 protein. Although LmRad51 expression is below the level of detection in exponentially growing cultures of Leishmania, high levels of LmRad51 mRNA and protein expression can be detected following exposure to the DNA-damaging agent phleomycin. LmRAD51 is one of the first examples of a DNA damage-inducible gene to be characterised in Leishmania, and will be invaluable in studying the contribution of homologous recombination to Leishmania virulence.
RAD51基因是大肠杆菌recA的同源物，在同源重组和DNA修复中起核心作用。本文描述了从锥虫寄生虫硕大利什曼原虫中鉴定出RAD51基因的过程。硕大利什曼原虫RAD51基因编码一个由377个氨基酸组成的多肽，预测分子量为41259道尔顿，与Rad51蛋白家族高度同源。重组的硕大利什曼原虫Rad51蛋白（LmRad51）在细菌表达系统中过表达，纯化至同质，并显示出与DNA结合并具有DNA刺激的ATP酶活性，这与先前报道的Rad51蛋白的生化特性一致。尽管在硕大利什曼原虫指数生长培养物中LmRad51的表达低于检测水平，但在暴露于DNA损伤剂博来霉素后可检测到高水平的LmRad51 mRNA和蛋白表达。LmRAD51是利什曼原虫中首个被表征的DNA损伤诱导基因实例之一，对于研究同源重组对利什曼原虫毒力的贡献将具有重要价值。
