The gene encoding gamma-actin from the cephalosporin producer Acremonium chrysogenum

The nucleotide sequence of a 3240-bp genomic fragment including the gamma - actin-encoding gene from Acremonium chrysogenum has been determined, showin g an open reading frame of 1691 bp, interrupted by five introns with fungal consensus splice-site junctions. The untranslated regions of the actA gene contain a consensus TATA box, a CCAAT motif, pyrimidine stretches and the polyadenylation sequence AATAA. The predicted protein (375 amino acids) rev ealed high identity to gamma -actins from fungi (> 90%). Gene phylogenies c onstructed using DNA and protein sequences support the grouping of A. chrys ogenum actin close to those from the majority of the filamentous fungi. The ActA gene is present as a single copy in the genome of A. chrysogenum; and its expression level, opposite to pcbC and cefEF cephalosporin biosyntheti c genes, was steady during cephalosporin fermentation, showing a single 1.4 -kb transcript.