CD4, the T-cell receptor for the human immunodeficiency virus, depends upon glycosylation for proper surface expression. Initial studies employing acute lymphoblastic leukemic cells were extended by the successful transfection of a plasmid containing the CDNA for CD4 into mutant and wild type Chinese hamster ovary cells. Characterization of these clones suggests that CD4 contains biantennary unsialylated complex-type oligosaccharides. The data also suggest that the inability of CD4 to reach the cell surface when it lacks carbohydrate is due to the selective degradation of unglycosylated CD4. The REV protein of HIV has been recently shown to lead to the premature transport of the partially spliced MRNA encoding the envelope glycoprotein from the nucleus to the cytoplasm. To develop a.system to examine the effects of REV, a means has been devised for generating nuclei in vitro around exogously added DNA. This method involves using extracts from Xenopus laevis where it has been demonstrated that nuclear assembly can be reconstituted. The availability of such preparations should allow examination of the mechanism of REV function. In other studies, examination has begun of the structure of the nuclear pore complex, across which REV, TAT, and other viral proteins cross following viral infection. The structure of the pore complex is explored using recombinant DNA techniques. The major nuclear pore glycoprotein np62 has been cloned, sequenced and expressed in cultured cells. The gene encoding this protein has been isolated and found to be 2.95 kb in length and devoid of introns. The availability of the primary sequence of this protein has allowed the preparation of anti-peptide antibodies which react with p62. These antibodies should prove useful for probing the function of the pore complex in the HIV life cycle.
