Human Immunodeficiency Virus: The Eighth Gene

Abstract
Human T-lymphotropic virus type III (HTLV-III/LAV) has been shown to contain at least four extra genes in addition to the three essential genes (gag, pol, env) for replication of most retroviruses. These genes are expressed by complex splicing mechanisms and utilization of overlapping reading frames. We now demonstrate that there is an eighth gene which encodes a protein which is immunogenic and recognized by sera of some HTLV-III seropositive people. The gene is highly conserved among all known HTLV-III isolates and exhibits a polymorphism at the 3′ end which distinguishes several molecular clones of the HTLV-IIIB cell line from those of other HTLV-III/LAV isolates. The function of this gene is unknown.