Structural and phylogenetic analysis of the gamma-actin encoding gene fromthe penicillin-producing fungus Penicillium chrysogenum

The nucleotide sequence of a 2994-bp genomic fragment, including the gamma -actin encoding gene from Penicillium chrysogenum, has been determined, sho wing an open reading frame (ORF) of 1756 bp interrupted by five introns wit h fungal consensus splice-site junctions. The 5' untranslated region contai ns a consensus TATA box, five CAAT motifs, and two large pyrimidine stretch es. The predicted protein (375 amino acids) revealed high identity to gamma -actins from fungi (>90%), and gene phylogenies support the grouping of P. chrysogenum actin close to those from the majority of the filamentous fung i. The actA gene is present as a single copy in the genome of P. chrysogenu m, and its expression is constitutive during penicillin fermentation, showi ng a single 1.4-kb transcript.