The role of the x gene in HTLV associated malignancy.

: Future studies on mechanisms of human T-cell leukaemia virus (HTLV) induced T-cell malignancy will focus on the role of the chi gene. This unique gene is found only in HTLV and the related bovine leukaemia virus, and is thought to be the transforming gene of these viruses, though direct proof of that role is still lacking. Recent studies indicate that the protein encoded by this gene has transcriptional regulatory properties similar to those of transcriptional regulatory proteins of other DNA viruses. An understanding of the mechanism of action of the HTLV chi protein will provide further insights into the hypothesis that cellular transformation and, ultimately, leukaemogenesis by HTLV is a result of aberrant transcription in T cells induced by the chi protein.