ISOLATION OF DNA MARKERS FOR THE RAT SAI-1 GENE FOR SUPPRESSION OF ANCHORAGE INDEPENDENCE BY USING REPRESENTATIONAL DIFFERENCE ANALYSIS

We have applied the representational difference analysis (RDA) to isol ate generic markers for a deletion on the rat chromosome RNO5q22-33. T his deletion occur-ed in anchorage independent sublines of a normal ra t fibroblast x mouse hepatoma cell hybrid (BS181) (Islam 1989). Normal rat tissue DNA provided the ''tester'' and the BS181 hybrid DNA the ' 'driver'' in the RDA hybridization/selection reactions. Out of twelve RDA derived DNA sequences that were analyzed in detail using a rat x m ouse cell hybrid panel for chromosome mapping, nine (75%) were found t o represent RNO5 deletions, whereas the other three were new RFLPs map ping to other chromosomes. In two cases, the RDA sequences were also a nalyzed by fluorescence in situ hybridization (FISH) and found to give distinct signals in the RNOq22-33 region. This result emphasizes the significance of the previous cytogenetic analysis of this hybrid which indicated the presence of a gene for the suppression of anchorage ind ependence, Sai 1, in this deletion region. The RDA derived sequences i solated by this work will provide a valuable source of new new genetic markers for the further detailed analysis of the Sai 1 deletion regio n.