Performance of casein kinase II in carbon catabolite repression (CCR) in Trichoderma reesei (Hypocrea jecorina)

Abstract

The bioproduction of ethanol from lignocellulosic materials is in the national interest, requiring the use of microbial strains capable of fermenting not only the main sugars, but also perform the enzymatic hydrolysis of carbohydrate polymers. Polysaccharides present in these materials are lignocellulosic feedstocks for production of second generation ethanol, due to its wide availability and rich in sugars. Cellulose is one of the three main components of lignocellulosic biomass, along with hemicellulose and lignin. Trichoderma reesei (anamorph of Hypocrea jecorina) is known for its high level of secretion of cellulase enzymes, which act on the hydrolysis of cellulose, making a key point in the production of bioethanol. Hydrolysis of cellulose results in the release of glucose molecules that can cause catabolite repression, that is, in the presence of glucose, a readily metabolisable carbon source decreases the expression of genes required for the use of other alternative carbon sources, CRE1 is a phosphoprotein responsible for repression in the presence of glucose, diminishing the expression of genes of cellulases. For CRE1 performing this function, it must be phosphorylated, it is likely that the protein, casein kinase II, fosforile CRE1 affecting catabolite repression. The objectives of this project are: to evaluate the role of casein kinase II in carbon catabolite repression in Trichoderma reesei by deletion of the genes encoding casein kinase II; analyze the expression of cellulase genes by RT-PCR; verify the interaction between CRE1 in its phosphorylated state and promoter regions of genes encoding for cellulase by gel shift assay or EMSA (Eletrophoretic Mobility Assay). The new mutant repressed catabolicamente obtained may be used in the hydrolysis of plant biomass contributing to the studies involving the production of biofuels.