INVOLVEMENT OF ETS, REL AND SP1-LIKE PROTEINS IN LIPOPOLYSACCHARIDE-MEDIATED ACTIVATION OF THE HIV-1 LTR IN MACROPHAGES

The HIV-1 promoter was used as a model to identify transcription facto rs involved in LPS-dependent transcription in RAW 264 murine macrophag es. Expression plasmids for Ets-2 and PU.I trans-activated the HN-I LT R and recombinant PU.I and an Ets-2 DNA binding domain/GST fusion prot ein bound to the 5' kappa B site of the HN-I enhancer: Ets-2 mRNA was LPS-inducible in RAW 264 cells and LPS stimulated phosphorylation of t hreonine 72 residue within the Ets-2 pointed domain. Induction of Ets- 2 and other LPS-responsive transcription factors was also observed upo n addition of plasmid DNA, which complicates interpretation of transie nt transfections. The proximal promoter region, containing two Spl sit es, was also LPS-responsive. We propose that the kappa B elements and the tandem Spl sites act as LPS response elements and that kappa B-med iated LPS action involves Ets and rel factors. (C) 1998 Wiley-Liss, In c.