The minimal regulatory region necessary for the expression of the Penicillium griseoroseum plg1 gene

Abstract

The expression of the Penicillium griseoroseum plg1 gene is induced by citric pectin and repressed by glucose. In this work, the minimal region of the plg1 gene promoter essential for expression in pectin and sucrose plus yeast extract was identified by using constructs containing the gfp ORF under control of the plg1 gene promoter. The fragment A (283 bp) is essential for plg1 expression in sucrose plus yeast extract. Fragment B (309 bp plus 184; core promoter) was critical for expression in pectin and abolished the catabolic repression by glucose. Therefore, the fragment of 776 bp (fragment A and B) is essential for the expression of the plg1 gene in natural inducing conditions (pectin as carbon source) and in sucrose plus yeast extract. The fragment B is a promising minimal promoter usable for heterologous expression in filamentous fungi, since genes that contain it could be activated by the presence of peel from citric fruits (which contains citric pectin) and are not affected by glucose in these agricultural by-products.