Analysis of the transcriptional regulation of YlODC gene from the dimorphic fungus Yarrowia lipolytica

SummaryPolyamines are small polycations essential for cell growth. Ornithine decarboxylase (ODC), the first enzyme of the polyamine synthesis pathway, is one of the most regulated enzymes of eukaryotes. In the present report, the transcriptional regulation of the gene encoding ODC from the dimorphic fungus Yarrowia lipolytica (YlODC) was analyzed. To this end we made a transcriptional fusion of its promoter with the ORF of the β-glucuronidase gene from Escherichia coli, and analyzed the effect of polyamines and the dimorphic transition on the rate of transcription. The results obtained show that there exists a weak but reproducible transcriptional regulation of YlODC under the analyzed conditions. Our data suggest that gene transcription is down-regulated by putrescine, and stimulated by spermidine. It is suggested that the simultaneous operation of transcriptional and post-translational regulatory mechanisms endows the cell with a more efficient mechanism to control the physiological processes that depend on polyamines.