MAPPING OF THE 70-KDA, 34-KDA, AND 11-KDA SUBUNIT GENES OF THE HUMAN MULTIMERIC SINGLE-STRANDED-DNA BINDING-PROTEIN (HSSB/RPA) TO CHROMOSOME BANDS 17P13, 1P35-P36.1, AND 7P21-P22

Human single-stranded DNA binding protein (hSSB/RPA) is a multimeric single-stranded DNA binding protein consisting of three subunits of 70 kDa, 34 kDa, and 11 kDa. Human SSB was isolated from HeLa cells as an essential factor for the in vitro replication of simian virus 40 DNA. We and others have isolated and sequenced CDNAs for each subunit of the SSB. The chromosome on which each gene is located was determined through the analysis of a panel of human/hamster somatic cell hybrids using the polymerase chain reaction with pairs of synthetic oligonucleotide primers form the 3'-untranslated sequences of the genes. Genomic clones for each gene were isolated from genomic cosmid library prepared from human lymphoblastoid cells. Using those clones as probes, we have carried out fluorescence in situ hybridization to human metaphase chromosomes and have mapped the 70 kDa subunit gene to 17p13, the 34 kDa subunit gene to 1p35-p36.1, and the 11 kDa subunit gene to 7p21-p22. Since hSSB participates in replication, recombination and repair of DNA, the physical mapping of hSSB genes may aid in the identification of human hereditary diseases associated with aberrant DNA reactions caused by genetic alterations of the hSSB.