[Lack of expression of the protein p53 gene in a human T-cell leukemia line]

Expression of the gene encoding the nuclear phosphoprotein p53 (a proto-oncogene classified in the same functional family as c-myc and E1a adenovirus gene) was examined in a human T-cell leukemia (KE-37R cell line). No p53 (or a modified product) could be detected by immunoprecipitation with monoclonal antibodies P Ab 421 and P Ab 122 in KE-37R cell extracts, and no p53-specific RNA was characterized by Northern blot analysis. Southern blot using a murine p53 cDNA clone as a probe, did not reveal any gross rearrangement in the structure of the gene. However, this molecular probe was not suited for investigating the 5' end of the gene which contains the promoter and the non coding exon 1. It is interesting to notice that in KE-37R cells, c-myc has been activated by a t(8; 14) (q24; q11) translocation, suggesting that the c-myc product might substitute to some functions normally requiring p53.