Nucleotide sequence of the URA1 gene of Saccharomyces cerevisiae.

The complete nucleotide sequence of the URA1 gene encoding dihydroorotic acid dehydrogenase (DHOdehase) is presented. This enzyme catalyses the conversion of DHO to orotic acid and plays a major role in the pyrimidine pathway, as DHO is the effector of the positive control of the transcription of at least four genes, URA1, URA3, URA4 and URA10. Comparisons between the amino acid sequence of the yeast DHOdehase and sequences of DHOdehases previously isolated from Dictyostellum discoïdum, Escherichia coli and Bacillus subtilis reveal no obvious homologies.