ASSIGNMENT OF CHINESE-HAMSTER P53 GENE (TP53) TO CHROMOSOME BAND 2P31, A REGION NOT INVOLVED IN THE KARYOTYPIC CHANGES OF A TUMORIGENIC CELL-LINE

The Chinese hamster tumor-derived cell line 835T2 exhibits specific ka ryotypic changes, including the loss and/or translocation of genetic m aterial. To investigate whether the p53 tumor suppressor gene was invo lved in the exchanges, cDNA from primary Chinese hamster cells was iso lated by using sense and antisense primers of the human p53 gene. The cDNA was sequenced, and the sequence was compared with the Syrian and human p53 cDNA reported sequences. The sequence homology was very elev ated, demonstrating that the cloned fragment contained part of the Chi nese hamster p53 gene. The corresponding genomic fragment was also clo ned and used as a biotin-labeled probe for in situ hybridization on Ch inese hamster chromosome spreads. Hybridization was visualized by avid in-FITC, and the assignment was done comparing the banding obtained wi th BamHI restriction enzyme and the location of the fluorescent signal s pattern of the same metaphase. The signals revealed that the p53 gen e (TP53) is localized on Chinese hamster chromosome band 2p31, which i s not involved in the karyotypic changes specific to the 835T2 cell li ne.