CLONING OF THE CDNAS FOR THE SMALL SUBUNITS OF BOVINE AND HUMAN DNA-POLYMERASE-DELTA AND CHROMOSOMAL LOCATION OF THE HUMAN GENE (POLD2)

cDNAs encoding the small subunit of bovine and human DNA polymerase de lta have been cloned and sequenced. The predicted polypeptides, 50,885 and 51,289 Daltons, respectively, are 94% identical, similar to the c atalytic subunits, The high degree of conservation of the polypeptides suggests an essential function for the small subunit in the heterodim eric core enzyme. Although the catalytic subunit of DNA polymerase 6 s hares significant homology with those of the herpes virus family of DN A polymerases, the small subunit of mammalian DNA polymerase delta is not homologous to the small subunit of either herpes simplex virus typ e 1 DNA polymerase (UL42 protein) or the Epstein-Barr virus DNA polyme rase (BMRF1 protein). Searches of the protein databases failed to dete ct significant homology with any protein sequenced thus far. PCR analy sis of DNA from a panel of human-hamster hybrid cell lines localized t he gene (POLD2) for the small subunit of DNA polymerase 6 to human chr omosome 7. (C) 1995 Academic Press, Inc.