Yeast gene RAD52 can substitute for phage T4 gene 46 or 47 in carrying out recombination and DNA repair.

The RAD52 gene of Saccharomyces cerevisiae and genes 46 and 47 of bacteriophage T4 are essential for most recombination and recombinational repair in their respective organisms. The RAD52 gene was introduced into expression vectors that were used to transform Escherichia coli. The expression of RAD52 was then induced, and the ability of RAD52 to complement phage mutants defective in gene 46 or 47 was determined with respect to the three criteria of phage growth, recombination, and recombinational repair. RAD52 gene expression was found to allow growth of gene 46 and 47 mutants under otherwise restrictive conditions, as measured by plaque formation and burst size. Expression of the RAD52 gene also restored the ability of gene 46 and 47 mutants to undergo recombination of rII markers. Furthermore, the RAD52 gene restored the ability of gene 46 and 47 mutants to undergo recombinational repair after UV irradiation. The published DNA sequence of gene RAD52 was compared with the published sequences of genes 46 and 47. Although overall sequence similarities were only marginally significant, RAD52 and gene 46 had substantial sequence similarity over a limited region.