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.
Bottom Line: 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.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.
Affiliation: Research Division Biotechnology and Microbiology, Institute of Chemical Engineering, TU Wien, Vienna, 1060, Austria.Show MeSH
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Mentions: We detected 351 genes (including 57 CAZymes) that were at least fourfold higher expressed on sophorose compared with the noninduced control (24 h glycerol preculture; Supporting Information Table S4). One hundred forty-six from them (including 44 CAZymes) were > 10-fold induced. Apart of CAZymes, genes encoding unknown conserved proteins, metabolic enzymes and membrane proteins that function in solute uptake were most abundant (Fig. 3). The rest of the genes identified (4–5% of the transcriptome) consisted of genes encoding enzymes which react with molecular oxygen, genes encoding small secreted cysteine-rich proteins (SSCRPs) and transcription factors (two C2H2-type, each one of BZIP-, myb- and MYND/zinc finger type, and 11 Zn(2)Cys(6) zinc cluster proteins; Supporting Information Table S4). The latter also included the already known regulatory genes xyr1, clr2 (Trire2:26163, which encodes the ortholog of the N. crassa and A. nidulans cellulase regulator CLR-2/ClrB; Coradetti et al., 2012; Häkkinen et al., 2014) and ace3 (Häkkinen et al., 2014).
Affiliation: Research Division Biotechnology and Microbiology, Institute of Chemical Engineering, TU Wien, Vienna, 1060, Austria.