hnRNP E1 but not E2 overexpression decreases HIV-1 structural protein levels. 293 cells were transfected with mycE1, mycE2 or the empty CMVmyc vector, alongside provirus HxBruR-/RI- andCMVPLAP. 48 hrs post transfection, cells were lifted in 1×PBS and a fraction (1/4) of the cells lysed in 9 M urea, 5 mM Tris pH8 and fractionated on SDS-PAGE gels. Protein was transferred to PVDF membrane and probed with antibody to p24. Blots were stripped in 62.5 mM TrisHCl pH 6.7, 2%SDS, 100 mM β-mercaptoethanol and reprobed with antibodies to gp160/120 (α gp120), hnRNP E1 and E2, myc and tubulin as indicated. (A) Results of western blotting. Antibodies and transfected plasmids are as indicated. (B) Relative SEAP expression in transfected cells. Levels were normalized to that of the empty CMVmyc vector control. Results shown are an average of three experiments. Error bars represent standard deviation.