Multiplication of an ancestral gene encoding secreted fungalysin preceded species differentiation in the dermatophytes Trichophyton and Microsporum
Multiplication of an ancestral gene encoding secreted fungalysin preceded species differentiation in the dermatophytes Trichophyton and Microsporum
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DOI：
10.1099/mic.0.26690-0
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发表时间：
2004-02-01
期刊：
影响因子：
2.8
通讯作者：
Monod, M
中科院分区：
文献类型：
--
作者：
Jousson, O;Léchenne, B;Monod, M
皮肤癣菌是人类和动物的致病真菌，其引起皮肤感染并且仅生长在角质层、指甲和毛发中。在以大豆蛋白为唯一氮源的培养基中，红色毛癣菌、须癣毛癣菌和犬小孢子菌分泌大量蛋白水解活性。这种蛋白水解活性被邻菲咯啉抑制55-75%，证明金属蛋白酶由所有三个物种分泌。利用构建在烟曲霉M36真菌溶素家族金属蛋白酶（MEP）基因上的共有探针，对烟曲霉、黑曲霉和M.犬MEP家族是从红色毛癣菌、须癣毛癣菌和M.狗基因组和蛋白质序列的系统发育分析揭示了一个强大的树组成的五个主要分支，其中每一个包括MEP序列类型从每个皮肤真菌物种。每种MEP类型在物种间显著保守（72-97%氨基酸序列同一性）。树状拓扑结构清楚地表明，MEP基因在皮肤癣菌中的增殖发生在物种分化之前。在含有大豆蛋白作为唯一氮源的培养基中，分泌的Meps占总分泌蛋白提取物的19-36%;通过蛋白水解和质谱法对蛋白条带的表征显示，三种皮肤真菌分泌由orthophosphate基因编码的两种Meps（Mep 3和Mep 4）。
Dermatophytes are human and animal pathogenic fungi which cause cutaneous infections and grow exclusively in the stratum corneum, nails and hair. In a culture medium containing soy proteins as sole nitrogen source a substantial proteolytic activity was secreted by Trichophyton rubrum, Trichophyton mentagrophytes and Microsporum canis. This proteolytic activity was 55-75% inhibited by o-phenanthroline, attesting that metalloproteases were secreted by all three species. Using a consensus probe constructed on previously characterized genes encoding metalloproteases (MEP) of the M36 fungalysin family in Aspergillus fumigatus, Aspergillus oryzae and M. canis, a five-member MEP family was isolated from genomic libraries of T rubrum, T mentagrophytes and M. canis. A phylogenetic analysis of genomic and protein sequences revealed a robust tree consisting of five main clades, each of them including a MEP sequence type from each dermatophyte species. Each MEP type was remarkably conserved across species (72-97% amino acid sequence identity). The tree topology clearly indicated that the multiplication of MEP genes in dermatophytes occurred prior to species divergence. In culture medium containing soy proteins as a sole nitrogen source secreted Meps accounted for 19-36% of total secreted protein extracts; characterization of protein bands by proteolysis and mass spectrometry revealed that the three dermatophyte species secreted two Meps (Mep3 and Mep4) encoded by orthologous genes.