The ß-importin KAP8 (Pse1/Kap121) is required for nuclear import of the cellulase transcriptional regulator XYR1, asexual sporulation and stress resistance in Trichoderma reesei.
The ß-importin KAP8 (Pse1/Kap121) is required for nuclear import of the cellulase transcriptional regulator XYR1, asexual sporulation and stress resistance in Trichoderma reesei.
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DOI：
10.1111/mmi.12944
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发表时间：
2015-04
影响因子：
3.6
通讯作者：
Kubicek CP
中科院分区：
文献类型：
--
作者：
Ghassemi S;Lichius A;Bidard F;Lemoine S;Rossignol MN;Herold S;Seidl-Seiboth V;Seiboth B;Espeso EA;Margeot A;Kubicek CP
子囊菌Trichoderma reesei是纤维素分解酶和半纤维素分解酶的工业生产者，并且作为其遗传调节的主要模型。它的大多数（半）纤维素分解酶都必须依赖于转录激活因子XYR 1。在这里，我们研究了核质穿梭机制，运输XYR 1通过核孔复合物。我们在里氏木霉中鉴定了14种核转运蛋白，其中8种被预测参与核输入，并产生了所有单基因缺失突变体。我们发现KAP 8，构巢曲霉KapI和酿酒酵母Kap 121/Pse 1的直系同源物，是GFP-XYR 1和纤维素酶基因表达的核招募所必需的。 用天然基因转化挽救了这种效应。Δ kap 8的转录组学分析显示，在纤维素酶诱导条件下，42种CAZymes，包括已知在XYR 1控制下的所有纤维素酶和半纤维素酶，显著下调。Δ kap 8菌株能够形成可育子实体，但在光照和黑暗条件下分生孢子数量均显著减少，对高渗透压、低pH和高温等非生物胁迫的敏感性增强。总之，这些数据强调了XYR 1的核输入在里氏木霉中纤维素酶和半纤维素酶基因调控中的重要性，并将KAP 8鉴定为该过程所需的主要核转运蛋白。
The ascomycete Trichoderma reesei is an industrial producer of cellulolytic and hemicellulolytic enzymes, and serves as a prime model for their genetic regulation. Most of its (hemi-)cellulolytic enzymes are obligatorily dependent on the transcriptional activator XYR1. Here, we investigated the nucleo-cytoplasmic shuttling mechanism that transports XYR1 across the nuclear pore complex. We identified 14 karyopherins in T. reesei, of which eight were predicted to be involved in nuclear import, and produced single gene-deletion mutants of all. We found KAP8, an ortholog of Aspergillus nidulans KapI, and Saccharomyces cerevisiae Kap121/Pse1, to be essential for nuclear recruitment of GFP-XYR1 and cellulase gene expression. Transformation with the native gene rescued this effect. Transcriptomic analyses of Δkap8 revealed that under cellulase-inducing conditions 42 CAZymes, including all cellulases and hemicellulases known to be under XYR1 control, were significantly down-regulated. Δkap8 strains were capable of forming fertile fruiting bodies but exhibited strongly reduced conidiation both in light and darkness, and showed enhanced sensitivity towards abiotic stress, including high osmotic pressure, low pH and high temperature. Together, these data underscore the significance of nuclear import of XYR1 in cellulase and hemicellulase gene regulation in T. reesei, and identify KAP8 as the major karyopherin required for this process.