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The Relation Between Promoter Chromatin Status, Xyr1 and Cellulase Expression in Trichoderma reesei

2015; Bentham Science Publishers; Volume: 17; Issue: 2 Linguagem: Inglês

10.2174/1389202917666151116211812

1875-5488

Thiago Machado Mello-de-Sousa, Alice Rassinger, Christian Derntl, Márcio José Poças-Fonseca, Robert L. Mach, Astrid R. Mach‐Aigner,

Fungal and yeast genetics research

The ascomycete Trichoderma reesei is used for the production of plant cell wall-degrading enzymes in industrial scale. The interplay of the transactivator Xyr1 and the repressor Cre1 mainly regulates the expression of these enzymes. During induc-ing conditions, such as in the presence of sophorose, the transcription of the two major cellulase-encoding genes, cbh1 and cbh2, is activated as well as the expression of xyr1. In the presence of D-glucose carbon catabolite repression mediated by Cre1 takes place and the expression of Xyr1 and the plant cell wall-degrading enzymes is down-regulated. In this study we compare the chromatin status of xyr1, cbh1, and cbh2 promoters in the wild-type strain and the Cre1-deficient strain Rut-C30. Chromatin rearrangement occurs in the xyr1 promoter during induction on sophorose. Chromatin opening and protein-DNA interactions in the xyr1 promoter were detected especially in a region located 0.9 kb upstream the translation start co-don, which bears several putative Cre1-binding sites and a CCAAT-box. Moreover, the xyr1 promoter is overall more acces-sible in a cre1-truncated background, no matter which carbon source is present. This makes the xyr1 regulatory sequence a good target for promoter engineering aiming at the enhancement of cellulase production.