Disclosed is a novel HIV gene comprising a set of open reading frames encoded with the template as the plus strand of the proviral DNA, and located in the region of HIV-1 long terminal repeat. The genes encode a set of antisense proteins, (HAPs) as well as smaller proteins, related to, and containing structural motif resembling that of chemokine proteins. Depending upon the ribosomal frameshift, a plurality of proteins may be translated from the antisense RNA. The smaller proteins have similarity with chemokine SDF-1 and may play a role as a cofactor with gp120 in the binding to and entry of HIV to a target cell.