Recombinant retroviruses containing the trans activator genes of human T-cell leukemia virus (HTLV) type II and human T-cell lymphotropic virus type III were constructed. The trans activator genes tat II and tat III were inserted into the murine retroviral vector pZIPNEOSV(X)1. Recombinant plasmids were transfected into the psi 2 and psi AM packaging cell lines that produce murine leukemia virions containing no retroviral RNA. Functional tat II and tat III gene products were expressed as demonstrated by trans activation of HTLV type I and II and human T-cell lymphotropic virus type III long terminal repeat-directed gene expression in the respective infected cells. Use of these recombinant vectors permits high-efficiency gene transfer into a wide variety of cells, thereby providing the opportunity to study the biochemical effects associated with tat II and tat III gene expression.

Rosen, C. A., Sodroski, J. G., Campbell, K., & Haseltine, W. A. (1986). Construction of recombinant murine retroviruses that express the human T-cell leukemia virus type II and human T-cell lymphotropic virus type III trans activator genes. Journal of Virology, 57(1), 379–384.