Title: Functional Analyses of Trichoderma reesei LAE1 Reveal Conserved and Contrasting Roles of This Regulator

Abstract

The putative methyltransferase LaeA is a global regulator that affects the expression of multiple secondary metabolite gene clusters in several fungi, and it can modify heterochromatin structure in Aspergillus nidulans. We have recently shown that the LaeA ortholog of Trichoderma reesei (LAE1), a fungus that is an industrial producer of cellulase and hemicellulase enzymes, regulates the expression of cellulases and polysaccharide hydrolases. To learn more about the function of LAE1 in T. reesei, we analyzied the effect of deletion and overexpression of lae1 on genome-wide gene expression. We discovered that in addition to positively regulating 7 of 17 polyketide or nonribosomal peptide synthases, genes encoding ankyrin-proteins, iron uptake, heterokaryon incompatibility proteins, PTH11-receptors, and oxidases/monoxygenases are major gene categories also regulated by LAE1. chromatin immunoprecipitation sequencing with antibodies against histone modifications known to be associated with transcriptionally active (H3K4me2 and -me3) or silent (H3K9me3) chromatin detected 4089 genes bearing one or more of these methylation marks, of which 75 exhibited a correlation between either H3K4me2 or H3K4me3 and regulation by LAE1. Transformation of a laeA-null mutant of A. nidulans with the T. reesei lae1 gene did not rescue sterigmatocystin formation and further impaired sexual development. LAE1 did not interact with A.more » nidulans VeA in yeast two-hybrid assays, whereas it interacted with the T. reesei VeA ortholog, VEL1. LAE1 was shown to be required for the expression of vel1, whereas the orthologs of velB and VosA are unaffected by lae1 deletion. Our data show that the biological roles of A. nidulans LaeA and T. reesei LAE1 are much less conserved than hitherto thought. In T. reesei, LAE1 appears predominantly to regulate genes increasing relative fitness in its environment.« less

Authors:

Karimi-Aghcheh, Razieh ^[1]; Bok, Jin Woo ^[2]; Phatale, Pallavi A. ^[3]; Smith, Kristina M. ^[3]; Baker, Scott E.  ^[4];

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Lichius, Alexander ^[1]; Omann, Markus ^[1]; Zeilinger, Susanne ^[1]; Seiboth, Bernhard ^[1]; Rhee, Catherine ^[2]; Keller, Nancy P. ^[2]; Freitag, Michael ^[4]; Kubicek, Christian P. ^[1]

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+ Show Author Affiliations

1. Vienna Univ. of Technology (Austria)
2. Univ. of Wisconsin-Madison, Madison, WI (United States)
3. Oregon State Univ., Corvallis, OR (United States)
4. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

Publication Date:

2013-02-01

Research Org.:

Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

Sponsoring Org.:

USDOE; National Institutes of Health (NIH)

OSTI Identifier:

1557228

Report Number(s):

PNNL-SA-94192
Journal ID: ISSN 2160-1836

Grant/Contract Number:  

AC05-76RL01830

Resource Type:

Accepted Manuscript

Journal Name:

G3

Additional Journal Information:

Journal Volume: 3; Journal Issue: 2; Journal ID: ISSN 2160-1836

Publisher:

Genetics Society of America

Country of Publication:

United States

Language:

English

Subject:

59 BASIC BIOLOGICAL SCIENCES; Trichoderma; epigenetic