SELECTION OF SPECIFIC GENE PROBES BY COMBINED USE OF LOW-STRINGENCY PCR AMPLIFICATION AND SOUTHERN-BLOT HYBRIDIZATION

We have developed a protocol to isolate a gene from which only limited (amino-acid) sequence information is available. It involves two PCR a mplifications using one constant primer and a set of nested primers an d subsequent crosswise Southern hybridization. The amplified DNA givin g a signal in both lanes is further processed for use in gene bank scr eening by applying standard procedures. In this way the structural gen e for a thiol protease, BLH1, the homologue of the bleomycin A (a canc erostatic drug) resistance gene of rabbit (and man), was isolated from yeast genomic DNA.