The glucose repressor genecre1 ofTrichoderma: Isolation and expression of a full-length and a truncated mutant form

Abstract

The cre1 genes of the filamentous fungi Trichoderma reesei and T. harzianum were isolated and characterized. The deduced CREI proteins are 46% identical to the product of the glucose repressor gene creA of Aspergillus nidulans, encoding a DNA-binding protein with zinc fingers of the C2H2 type. The cre1 promoters contain several sequence elements that are identical to the previously identified binding sites for A. nidulans CREA. Steady-state mRNA levels for cre1 of the T. reesei strain QM9414 varied depending on the carbon source, being low on glucose-containing media. These observations suggest that cre1 expression may be autoregulated. The T. reesei strain Rut-C30, a hyper-producer of cellulolytic enzymes, was found to express a truncated form of the cre1 gene (cre1-1) with an ORF corresponding to a protein of 95 amino acids with only one zinc finger. Unlike QM9414 the strain Rut-C30 produced cellulase mRNAs on glucose-containing medium and transformation of the full-length cre1 gene into this strain caused glucose repression of cbh1 expression, demonstrating that cre1 regulates cellulase expression.

Xyr1 receives the lactose induction signal and regulates lactose metabolism in Hypocrea jecorina

“…Furthermore, comparison of xyr1 transcript levels of a Cre1-negative strain [23] with the wild-type cultivated on glucose and lactose revealed xyr1 transcription on lactose to be governed by a derepression mechanism. In contrast to xyr1 transcript formation, transcription of the xyn1 gene is additionally subject to a lactose specific induction mechanism different from the xylose-mediated induction.…”

Global nutrient profiling by Phenotype MicroArrays: a tool complementing genomic and proteomic studies in conidial fungi

“…These factors have been intensively studied in A. nidulans, N. crassa, H. jecorina, and Acremonium chrysogenum (Bailey and Arst, 1975;Kudla et al, 1990;Dowzer and Kelly, 1991;Caddick et al, 1994;Strauss et al, 1995;Ilmén et al, 1996;Platt et al, 1996;Ravagnani et al, 1997;Marzluf, 1997;Wilson and Arst, 1998;Jekosch and Kück, 2000;Felenbok et al, 2001). In this type of experiment, growth of a parent strain and a respective mutant would be compared on every medium composition, which would reveal those particular nutrients whose utilization depends on the mutated wide-domain control gene.…”

“…Its most observed phenotype is due to the creA/cre1 gene, which encodes a C 2 H 2 -zinc fingercontaining transcriptional repressor (Dowzer and Kelly, 1991;Strauss et al, 1995;Ilmén et al, 1996). It ensures the utilization of glucose and some other carbon sources in preference to a large variety of other carbon compounds, which either yield less energy during assimilation (e.g., C 2 -components), or require a considerable amount of energy for becoming assimilable (e.g., extracellular macromolecules, for which hydrolases must be exported via a secretory pathway).…”

“…To determine the utilization of which carbon sources is actually affected by the carbon catabolite repression, Seidl et al (2008) investigated the differences in the growth of a cre1-truncated mutant strain of H. jecorina (RUT C30) (Ilmén et al, 1996) and the respective parent strain NG 14. The results (Fig.…”

Sistema de expressão induzido por estradiol em <i>Saccharomyces cerevisiae</i>.

“…O sistema celulolítico de T. reesei envolvendo o promotor celobiohidrolase I (Pcbh1) é conhecido devido a sua capacidade de ser induzido por diferentes sacarídeos como celulose, sacarose e lactose em, pelo menos, 1000 vezes (CARLE-URIOSTE et al, 1997). No entanto ele é regulado por repressão catabólica, sendo reprimido pelo produto da degradação do próprio sacarídeo, ou seja, a glicose (ABRAHÃO-NETO et al, 1995;ILMÉN et al, 1996;ILMÉN;THRANE;PENTTILA, 1996). Porém, com as técnicas de gene-knockout, engenharia genética, e sistemas de transformação tornou-se possível o desenvolvimento de cepas capazes de produzir e secretar grandes quantidades de proteínas homólogas e/ou heterólogas (BOUWS; WATTENBERG; ZORN, 2008;CHERRY;FIDANTSEF, 2003;MARTINEZ et al, 2008;VINZANT et al, 2001).…”