Molecular and genetic analysis of the Cryptococcus neoformans MET3 gene and a met3 mutant.
Molecular and genetic analysis of the Cryptococcus neoformans MET3 gene and a met3 mutant.
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新型隐球菌 MET3 基因和 met3 突变体的分子和遗传分析。
DOI：
10.1099/00221287-148-8-2617
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
McCusker,JohnH
中科院分区：
文献类型：
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作者：
Yang,Zhonghui;Pascon,RenataC;Alspaugh,Andrew;Cox,GaryM;McCusker,JohnH
通过与酿酒酵母中相应的met3突变互补，克隆了新生隐球菌编码三磷酸腺苷硫酰基酶的基因。序列分析表明，推导的氨基酸序列具有较高的相似性。新生酶Met3p和其他真菌三磷酸腺苷硫酰基酶。交流电。通过定向插入突变获得了具有预期营养缺陷型的新生单胞菌Met3突变株，并将其重组为Met+。新基因突变株在黑色素形成方面存在明显缺陷，生长速度显著降低，耐热性显著提高。在小鼠吸入性感染模型中，这3个突变体是无毒的，在小鼠体内的存活能力不足。结果表明，与酵母型组织胞浆菌不同的是，新的形式蛋氨酸生物合成途径的硫酸盐同化臂在体外发挥着重要作用，即使在大量外源蛋氨酸存在的情况下，也是毒力的关键，甚至是体内生存的关键。
TheCryptococcus neoformans MET3cDNA (encoding ATP sulfurylase) was cloned by complementation of the correspondingmet3mutation inSaccharomyces cerevisiae. Sequence analysis showed high similarity between the deduced amino acid sequence of theC. neoformansMet3p and other fungal ATP sulfurylases. AC. neoformans met3mutant was made by targeted insertional mutagenesis, which had the expected auxotrophic phenotype, and reconstituted themet3mutant to Met+.In vitro, theC. neoformansmet3mutant had a substantial defect in melanin formation, significantly reduced growth rate, and greatly increased thermotolerance. In the murine inhalation infection model, themet3mutant was avirulent and was deficient in its ability to survive in mice. It is concluded that, in contrast to the yeast form ofHistoplasma capsulatum, inC. neoformansthe sulfate-assimilation arm of the methionine biosynthetic pathway plays an important rolein vitro, even in the presence of abundant exogenous methionine, and is critical for virulence, and indeed for survival,in vivo.