Two separate cis-active elements of the vasoactive intestinal peptide genemediate constitutive and inducible transcription by binding different setsof AP-1 proteins

Vasoactive intestinal peptide (VIP) gene expression is highly restricted th roughout the neuroaxis and regulated by extracellular factors that activate tyrosine- or serine/threonine-directed protein kinase pathways. Cytokine, cyclic AMP, and tissue-specific response elements on the VIP gene have been characterized, Those mediating responsiveness to protein kinase C have not , The endogenous VIP gene and a 5.2-kilobase pair (kb) VIP-luciferase repor ter gene, are up-regulated by phorbol 12-myristate 13-acetate (PMA) in SK-N -SH neuroblastoma cells. PMA stimulation was abolished by deletion of seque nces at -1.37 to -1.28 or -1.28 to -0.904 kb, but not by removal of the sin gle phorbol ester response element (TRE; TGACTCA) located at -2.25 kb. Muta tion of sites at -1.32 or -1.20 that mediate neurotrophin responsiveness of the VIP gene (Symes, A., Lewis, S,, Corpus, L., Rajan, P., Hyman, S.E,, an d Fink, J.S. (1994) Mol. Endocrinol. 8, 1750-1763) each reduced PMA inducti on in SK-N-SH cells by >50%, and double mutation abolished it. The two muta tions also reduced basal VIP reporter gene transcription in SH-EP neuroblas toma cells expressing VIP constitutively. Both cis-active elements bound pr e-existing AP-1 proteins in SH-EP- or PIMA-stimulated SK-N-SH cell nuclear extracts. The AP-1 complex at both sites contained a Fos-related protein wi th c-Jun in SH-EP cells and c-Fos with a Jun-related protein in SK-N-SH cel ls. Recruitment of combinatorially distinct AP-1 complexes to these element s may underlie cell type-specific regulation of the VIP gene.