Coding potential of the X region of human T-cell leukemia/lymphotropic virus type II

Differences in proteins produced by certain gene sequences could explain the different diseases caused by human T-cell leukemia/lymphotropic viruses I and II (HTLV-I and HTLV-II). The viruses have similar genes and both can cause T cells to turn cancerous. However, HTLV-II has not been conclusively linked to any disease yet, unlike HTLV-I, which has been linked to adult T cell leukemia and a muscle disease. Analysis of the X region of the viral genes reveals that each virus produces different proteins. Research has shown that mutations in the X region can produce a less virulent virus.