CHEMICALLY SELECTED SUBCLONES OF THE CEM CELL-LINE DEMONSTRATE RESISTANCE TO HIV-1 INFECTION RESULTING FROM A SELECTIVE LOSS OF NF-KAPPA-B DNA-BINDING PROTEINS

To delineate cellular genes that are required for optimal HIV-1 infect ion, CEM cells were subjected to treatment with the chemical mutagen e thylmethanesulfonate (EMS) and subclones were selected based on their increased resistance to HIV-1 infection and reduced syncytium formatio n, despite relatively normal CD4 expression (20,000 to 25,000 receptor s/cell). Two subclones with this phenotype demonstrated a diminished c apacity of HIV-1 long terminal repeat-chloramphenicol acetyl transfera se expression either after treatment with the protein kinase C activat or PMA, or through Tat-mediated transactivation. In this study, we sho w that the cellular levels of the NF-kappa B DNA binding proteins (but not AP1 or SP1) are markedly reduced in these cell mutants both at th e mRNA and protein levels, resulting in reduced nuclear localization o f p50/p65 after PMA induction or treatment with the lymphokine TNF-alp ha. Transient reconstitution with a plasmid expressing p50 resulted in partial recovery of PMA-inducible LTR-chloramphenicol acetyl transfer ase expression. These data suggest that, at least in the CEM T cell li ne, a selective reduction in the NF-kappa B DNA binding proteins is su fficient to curtail HIV-1 infection.