The cefT Gene Encodes a MSF like Protein in Acremonium chrysogenum C10. Amplification of the cefT leads to Cephalosporin Overproduction.
Ullán R.V.; Casqueiro, J.; Bañuelos. O.; Gutiérrez, S.; Naranjo, L.; Martín de Valmaseda E. and Martín, J.F.
Area of Microbiology, Faculty of Biology and Environmental Sciences, University of León. 24071, León (Spain).
Acremonium chrysogenum is industrially used as cephalosporin C producer. Transcriptional analysis of the region downstream of the pcbAB gene revealed the presence of two different transcripts corresponding to two new open reading frames. ORF3 encodes a putative D-hydroxyacid dehydrogenase and cefT (for transmembrane protein) encodes a multidrug efflux pump belonging to the Major Faciltator Superfamily (MFS) of membrane proteins. The CefT protein has 12 transmembrane spanners (TMS) and contains motifs A, B, C, D2 and G characteristic of the Drug: H+ antiporter 12-TMS group of the major facilitator superfamily. The CefT protein confers resistance to some toxic organic acids including isovaleric acid and phenylacetic acid. Targeted inactivation of ORF3 and cefT with the double marcker technique revealed that they are not essential for cephalosporin biosynthesis. However amplification of the cefT gene results in increments of up to 100% in cephalosporin production in A. chrysogenum C10 strain. It seems that the CefT protein is involved in cephalosporin exportation in A. chrysogenum or transmembrane signal transduction.
