RAD1 Homolog (RAD1)

The cDNAs encode the 282-amino acid RAD1 isoform, which is 90% and 27% identical to mouse Rad1 and S. pombe rad1+, respectively.In the fission yeast S. pombe, the rad1+ gene product is required for DNA repair and replication. The longer cDNA, called Hrad1A, encodes a 282-amino acid polypeptide, while Hrad1B encodes a 163-amino acid polypeptide. Northern blot analysis revealed that human RAD1 is expressed as mRNAs of 5, 3, and 1.3 kb in a variety of human tissues, with higher levels present in some cancer cell lines. Northern blot analysis of cells subjected to ultraviolet radiation demonstrated that human RAD1 expression is not induced in response to DNA damage. Purified RAD1 exhibited terminal exonuclease activity on double-stranded DNA, with a preference for 3-prime ends.