INHIBITION OF CELLULAR GLYCOPROTEIN INCORPORATION INTO HUMAN IMMUNODEFICIENCY VIRUS-LIKE PARTICLES BY COEXPRESSION OF ADDITIONAL CELLULAR INTERACTION PARTNER

We examined the concepts of whether cellular surface glycoprotein over expressed in heterologous cells can be efficiently incorporated into l entiviral particles and whether incorporation is blocked when a natura l interaction partner is coexpressed. Human CD4 and a truncated versio n lacking the cytoplasmic C terminus, expressed in 293T cells, were ef ficiently incorporated into Env-defective human immunodeficiency virus type 1 virus-like particles. However, on coexpression of p56(lck), th e natural binding partner of the CD4 C-terminal domain in T lymphocyte s, incorporation of the wild-type CD4 was completely abolished, wherea s incorporation of the C-terminally truncated mutant remained unaffect ed. Confocal microscopy and detergent solubility assays did not reveal any significant difference in the distribution of wild-type CD4 at th e plasma membrane in the presence or absence of p56(lck). These result s give some insight into the processes governing protein incorporation into the lipid bilayer of lentiviruses. (C) 1998 Academic Press.