AN UNUSUAL STRUCTURE OF A PUTATIVE T-CELL ONCOGENE WHICH ALLOWS PRODUCTION OF SIMILAR PROTEINS FROM DISTINCT MESSENGER-RNAS

We previously identified a putative T cell oncogene on chromosome 11 near a translocation t(11;14)(p15;q11) in a human T cell tumour. The gene is transcribed from distinct promoters which have unrelated sequences, which occur within close but distinct methylation-free islands and which allow cell specific production of mRNA. The alternative first exons each contain a protein initiation codon from which two species of protein can be made, differing by only a single amino acid. The protein sequence is highly conserved between man and mouse (98%) and the same single codon difference between alternative first exons is also conserved. This is, therefore, a new form of eukaryotic gene organization from which similar proteins can be made from distinct mRNA species.