Abstract
A Neurospora gene bank in plasmid pRK9 was used to complement pyrimidine auxotrophs in E. coli. Two plasmids were obtained that complement a pyrF mutant of E. coli. These plasmids hybridise to Neurospora DNA and transform a pyr-4 strain of Neurospora. The promoter used in expressing the orotidine 5′-monophosphate carboxylase in E. coli is within the Neurospora sequence.