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Nucleo‐cytoplasmic shuttling dynamics of the transcriptional regulators XYR1 and CRE1 under conditions of cellulase and xylanase gene expression in T richoderma reesei
Author(s) -
Lichius Alexander,
SeidlSeiboth Verena,
Seiboth Bernhard,
Kubicek Christian P.
Publication year - 2014
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.12824
Subject(s) - cellulase , catabolite repression , trichoderma reesei , biology , gene expression , microbiology and biotechnology , repressor , psychological repression , transcription (linguistics) , regulation of gene expression , transcriptional regulation , conidiation , transcription factor , gene , biochemistry , enzyme , virulence , linguistics , philosophy , mutant
Summary T richoderma reesei is a model for investigating the regulation of (hemi‐)cellulase gene expression. Cellulases are formed adaptively, and the transcriptional activator XYR1 and the carbon catabolite repressor CRE1 are main regulators of their expression. We quantified the nucleo‐cytoplasmic shuttling dynamics of GFP ‐fusion proteins of both transcription factors under cellulase and xylanase inducing conditions, and correlated their nuclear presence/absence with transcriptional changes. We also compared their subcellular localization in conidial germlings and mature hyphae. We show that cellulase gene expression requires de novo biosynthesis of XYR1 and its simultaneous nuclear import, whereas carbon catabolite repression is regulated through preformed CRE1 imported from the cytoplasmic pool. Termination of induction immediately stopped cellulase gene transcription and was accompanied by rapid nuclear degradation of XYR1 . In contrast, nuclear CRE1 rapidly decreased upon glucose depletion, and became recycled into the cytoplasm. In mature hyphae, nuclei containing activated XYR1 were concentrated in the colony center, indicating that this is the main region of XYR1 synthesis and cellulase transcription. CRE1 was found to be evenly distributed throughout the entire mycelium. Taken together, our data revealed novel aspects of the dynamic shuttling and spatial bias of the major regulator of (hemi‐)cellulase gene expression, XYR1 , in T . reesei .