IDENTIFICATION, CHROMOSOMAL MAPPING AND TISSUE-SPECIFIC EXPRESSION OFHREV3 ENCODING A PUTATIVE HUMAN DNA-POLYMERASE-ZETA

The Saccharomyces cerevisiae REV3 gene encodes the catalytic subunit o f a non-essential DNA polymerase zeta, which is required for mutagenes is. The rev3 mutants significantly reduce both spontaneous and DNA dam age-induced mutation rates. We have identified human cDNA clones from two different libraries whose deduced amino acid sequences bear remark able homology to the yeast Rev3, and named this gene hREV3, The hREV3 gene was mapped to chromosome 1p32-33 by fluorescence in situ hybridiz ation, The hREV3 encodes an mRNA of >10 kb, and its expression varies in different tissues and appears to be elevated in some but not all of the tumor cell lines we have examined. In light of recent reports of a putative mouse REV3, these results indicate that mammalian cells may also contain a mutagenic pathway which aids in cell survival at the c ost of increased mutation.