[Mapping of the transforming gene by fluorescence in situ hybridization]

A transforming gene of human nasopharyngeal carcinoma was cloned from Chinese nasopharyngeal carcinoma cell line CNE2. This gene was different from a number of known oncogenes as was reported previously. The NPC transforming gene was 16kb in size, and the Alu negative 2.8kb fragment was cloned into pSP70 plasmid. Linearized Tx pSP70 recombinant plasmid was nick translated in the presence of biotin-11-dUTP, incubated with an excess of sonicated human DNA, and used as a probe for fluorescence in situ hybridization. Signals of hybridization were detected by successive treatments with FITC-labeled avidin. 57% of grains were located on chromosome 8; 51.8% of them were mapped to the 8q23-->8q24.1 region of chromosome 8's. The Tx gene, therefore, could be assigned to the band 8q23-->8q24.1.