Gel mobility shift scanning of pectin-inducible promoter from Penicillium griseoroseum reveals the involvement of a CCAAT element in the expression of a polygalacturonase gene

• Main Authors: Andréa de O.B. Ribon, João Batista Ribeiro, Daniel B. Gonçalves, Marisa V. de Queiroz, Elza F. de Araújo
• Format: Article
• Language: English
• Published: Sociedade Brasileira de Genética 2009-01-01
• Series: Genetics and Molecular Biology
• Subjects: Penicillium griseoroseum; polygalacturonase; 5' upstream regulatory sequence; electrophoretic mobility shift assay
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572009000100019

Previous reports have described pgg2, a polygalacturonase-encoding gene of Penicillium griseoroseum, as an attractive model for transcriptional regulation studies, due to its high expression throughout several in vitro growth conditions, even in the presence of non-inducing sugars such as sucrose. A search for regulatory motifs in the 5' upstream regulatory sequence of pgg2 identified a putative CCAAT box that could justify this expression profile. This element, located 270 bp upstream of the translational start codon, was tested as binding target for regulatory proteins. Analysis of a 170 bp promoter fragment by electrophoretic mobility shift assay (EMSA) with nuclear extracts prepared from mycelia grown in pectin-containing culture medium revealed a high mobility complex that was subsequently confirmed by analyzing it with a double-stranded oligonucleotide spanning the CCAAT motif. A substitution in the core sequence for GTAGG partially abolished the formation of specific complexes, showing the involvement of the CCAAT box in the regulation of the polygalacturonase gene studied.