Expression of the Escherichia coli recA gene in the yeast Saccharomyces cerevisiae

The isolation of the protein coding region of the recA gene from Escherichia coli by extensive Bal31 digestion is described. The structural recA gene was ligated into an extrachromosomally replicating yeast expression vector, downstream of the yeast alcohol-dehydrogenase gene promoter region, to produce pADHrecA plasmid. The pADHrecA plasmid was transformed into the wild-type and the repair deficient strains of Saccharomyces cerevisiae. The crude protein samples were extracted from the individual yeast transformants. A 38 kDa protein was present in all transformants containing the recA gene on plasmid. Thus the recA gene from E coli was successfully expressed in cells from a lower eukaryote.