A NEW HYBRID CELL-LINE CONTAINING ONLY HUMAN-CHROMOSOME-15 SELECTED THROUGH FLUORESCENCE IN-SITU HYBRIDIZATION AND CHARACTERIZED BY ALU-PCRAMPLIFICATION OP THE HUMAN DNA

Human Cot1 DNA directly labeled with dUTP-fluorochromes (FITC, Rhodami n) and used as a probe, allowed rapid detection of one or a few human chromosomes in human-hamster hybrid cells by in situ hybridization (FI SH). A hybrid cell line containing only a human acrocentric chromosome was isolated (CH35B2D). The DNA from this hybrid was used for PCR amp lification with a single Alu (A33) primer. After agarose gel electroph oresis, a continuum of intense bands of between 400-700 bp was observe d with A33-PCR products. No amplified product was visible with hamster DNA. FISH on normal human metaphases of biotinylated Alu-PCR products obtained with Alu A33 and competition with human Cot1 DNA showed deco ration, with high specificity for chromosome 15. It was identified aft er R banding obtained with PI or DAPI in an antifade adjusted to pH11 with NaOH. Under the applied conditions, the Alu (A33) products are ex pected to be useful for characterization, by specific decoration of ch romosome 15 aberrations in pathological cells. CH35B2D could be employ ed for functional studies of genes located on chromosome 15.