A DNA motif present in alpha V integrin promoter exhibits dual binding preference to distinct transcription factors.

Le résumé fourni par la source

Antisense inhibition of the RelA subunit but not the NFKB1 subunit of NK-kappa B transcription factor results in a block of cellular adhesion and inhibition of tumor cell growth in vitro and in vivo. Studies aimed at dissecting the molecular mechanism of antisense relA action led to our identification of a kappa B-like motif present in aV integrin promoter. The alpha V/kappa B motif is closely related to RelA/c-Rel-binding sequences, such as 65-2 and TF-1. However, unlike these two kappa Blike motifs, the alpha V/kappa B motif detected a nuclear Sp1 activity distinct from kappa B activity, which was subsequently confirmed to be derived from Sp1. In comparison to the conventional GC box-containing Sp1 motif, the alpha V/kappa B motif also binds in vitro to c-Rel and RelA but not to NFKB1. Antisense inhibition of RelA inhibited the alpha V/kappa B activity. Direct in vivo competition of alpha V/kappa B-binding activity by a decoy approach also resulted in inhibition of alpha V/kappa B activity in intact cells. A variant of the alpha V/kappa B motif was found to retain the dual ability to detect Sp1 and the NF-kappa B complex in the nuclear and cytoplasmic extracts. Such dual interacting ability of a DNA motif offers yet another way of gene regulation in vivo and hence can affect cellular growth. Our results identify alpha V integrin as one of the molecular targets for relA/NF-kappa B and may explain growth inhibition by antisense relA.

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