ALLELE-SPECIFIC HYBRIDIZATION OF LIPOPROTEIN-LIPASE AND FACTOR-V LEIDEN MISSENSE MUTATIONS WITH DIRECT LABEL ALKALINE PHOSPHATASE-CONJUGATED OLIGONUCLEOTIDE PROBES

Direct label alkaline phosphatase (AP) conjugated oligonucleotide prob es (AP-DNA) were prepared to assess their utility for allele-specific detection of single base substitutions. Oligonucleotide conjugates wer e designed to detect point mutations in the genes for lipoprotein lipa se (LPL) and coagulation factor-V (FV). Genomic DNA samples, including ones known to harbor point mutations in the genes for LPL and FV, wer e prepared from whole blood and subjected to polymerase chain reaction (PCR). PCR products were analyzed by Southern hybridization with the allele-specific AP-DNA probes and restriction endonuclease analysis. T hermal profiles for hybridization indicate optimal allele-specific sel ectivity was achieved with temperatures ranging from 45 degrees C to 5 5 degrees C al a total Na+ concentration of 150 mM. Under these condit ions the base changes studied were easily discriminated with allele sp ecific hybridization signals in excess of 200:1 as estimated by scanni ng densitometry. Complete concordance was observed between hybridizati on and restriction analyses for 175 LPL and 201 FV clinical and refere nce samples. The total time for analysis of the PCR products was less than 2 h with a dot blot hybridization protocol.