In vivo analysis of Aspergillus fumigatus developmental gene expression determined by real-time reverse transcription-PCR
In vivo analysis of Aspergillus fumigatus developmental gene expression determined by real-time reverse transcription-PCR
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DOI：
10.1128/iai.01483-07
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发表时间：
2008-08-01
影响因子：
3.1
通讯作者：
Sheppard, Donald C.
中科院分区：
文献类型：
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作者：
Gravelat, Fabrice N.;Doedt, Thomas;Sheppard, Donald C.
关于侵袭性曲霉病期间烟曲霉的发育阶段知之甚少。我们对侵袭性肺曲霉病小鼠的肺样本进行实时逆转录PCR分析，以确定A。烟曲霉基因在特定的发育阶段表达。在已建立的感染中，A.烟曲霉表现出特定的基因的mRNA表达发育能力的菌丝，如stuA。而分生孢子和感受态前菌丝表达的基因mRNA则未检测到。已知真菌毒素合成所需的许多基因，包括aspHS、gliP、mitF和metAp，在体外由发育能力强的菌丝表达。有趣的是，这些基因中的每一个在侵入性感染期间的表达水平都显著高于体外。发现体外培养条件高度依赖于gliP mRNA的表达。此外，在体外和体内，发现gliP的表达依赖于转录因子StuA。因此，在已建立的侵入性感染中，发育能力强的菌丝占主导地位，许多真菌毒素基因在体内高水平表达。这些结果强调了评估由主管菌丝表达的推定毒力因子和分析侵入性感染过程中而不是单独在体外的基因表达水平的重要性。
Very little is known about the developmental stages of Aspergillus fumigatus during invasive aspergillosis. We performed real-time reverse transcription-PCR analysis on lung samples from mice with invasive pulmonary aspergillosis to determine the expression of A. fumigatus genes that are expressed at specific stages of development. In established infection, A. fumigatus exhibited mRNA expression of genes specific to developmentally competent hyphae, such as stuA. In contrast, mRNA of genes expressed by conidia and precompetent hyphae was not detected. Many genes required for mycotoxin synthesis, including aspHS, gliP, mitF, and metAp, are known to be expressed by developmentally competent hyphae in vitro. Interestingly, each of these genes was expressed at significantly higher levels during invasive infection than in vitro. The expression of gliP mRNA in vitro was found to be highly dependent on culture conditions. Furthermore, gliP expression was found to be dependent on the transcription factor StuA both in vitro and in vivo. Therefore, developmentally competent hyphae predominate during established invasive infection, and many mycotoxin genes are expressed at high levels in vivo. These results highlight the importance of the evaluation of putative virulence factors expressed by competent hyphae and analysis of gene expression levels during invasive infection rather than in vitro alone.