Mechanism of activation of HuBlym-1 gene unresolved.

The HuBlym-1 gene has been isolated from Burkitt's lymphoma DNA on the basis of its reported ability to produce foci of cells when NIH 3T3 cells are transfected with it. The sequence of HuBlym-1 has been reported but it has not been established whether the sequence of the transforming gene differs from that of the gene in normal tissue, as might be expected from the common observation of mutational activation of proto-oncogenes into oncogenes. I report here that there are no differences between the sequences of three recombinant DNA clones that were isolated from Burkitt's cell lines and that cross-hybridize to HuBlym-1 but do not induce foci when transfected into NIH 3T3 cells, and the reported sequence of Burkitt's lymphoma Blym. Also there is no obvious or consistent increase in the transcription of the HuBlym-1 gene in Burkitt's lymphoma cell lines of the type that might otherwise have accounted for its transforming activity even in the absence of a mutation. How the HuBlym-1 gene is activated therefore remains a mystery.