草菇GH61家族基因的生物信息学分析及金属离子对其表达水平的影响

Bioinformatic and gene expression analyses of the GH61 family genes of Volvariella volvacea

在前期工作中发现草菇含有30个GH61家族基因同源物(Vv_gh61_1至Vv_gh61_30),进一步分析了这些基因的结构特点以及其编码蛋白基本性质和系统进化关系,并研究了Cu^(2+)和Mn^(2+)对基因表达水平的影响。分析表明有17个草菇GH61基因串联成6个基因簇,存在明显的串联重复现象,系统发育树与基因外显子位置分析表明串联重复基因分布在同一进化分枝上并具有相似的基因结构,串联重复基因编码序列一致性在71%–94%之间。草菇GH61编码蛋白的氨基酸数目在217–442aa之间,分子量和等电点分别介于22.4–45.4k Da和5.2–9.3之间,绝大多数都含有信号肽并定位在细胞外,都含有Glyco_hydro_61功能域以及CBM1、peroxidase等多样化的功能域,系统进化树表明草菇GH61家族基因具有3个主要进化分枝,与灰盖鬼伞等的GH61基因有较近的进化关系。金属离子诱导作用显示,Mn2+对草菇GH61家族基因的表达水平存在诱导作用而Cu2+的诱导作用不明显。

Thirty putative GH61 family genes（Vv_gh61_1 to Vv_gh61_30） in the genome of Volvariella volvacea were identified previously. In this study, the genetic structure of these genes as well as their encoded proteins and phylogenetic relationships were reanalyzed. The effect of bivalent copper and manganese ions on the gene expression level was also investigated. The results showed that 17 out of 30 GH61 family genes distributed in 6 gene clusters with the form of tandem duplication. Analysis of phylogenetic trees and exon position reveals that these genes of the same cluster share the final phylogenetic clades and have similar gene structure, and most of amino acid sequences encoded by the genes in the same cluster have high identities（71%–94%）. GH61 proteins of V. volvacea have 217–422aa in length, and their molecular weight and isoelectric point range at 22.4–45.4k Da and 5.2–9.3, respectively. The majority of GH61 proteins of V. volvacea have the signal peptides and thereby are secretable. The functional domains of Glyco_hydro_61, CBM1 and peroxidase are found in GH61 proteins of V. volvacea. Phylogenetic tree shows that GH61 family genes of V. volvacea cluster in three major clades with closely evolutionary relationships to those of Coprinopsis cinerea. The expressional levels of GH61 family genes increase while the genes are induced by Mn2＋ at 100μmol/L, but induction effect of Cu2＋ is indistinctive.