The vasopressin gene non-canonical Hogness box: effect on protein binding and promoter function.

Comparison of the promoter sequences of the genes encoding the neuropeptide hormone vasopressin from a number of organisms has revealed that they do not contain a classical Hogness box. In all vertebrate species examined, the canonical TATA box is replaced with a CATA sequence. We hypothesised that this conserved modified sequence may play a role in the regulation of vasopressin promoter activity. We used electrophoretic mobility shift assays to show that TATA and CATA sequences generate different complexes with SON nuclear proteins. Further, the transfection of wild-type (CATA) and mutated (TATA) VP promoter-reporter constructs into a heterologous cell line demonstrated a sequence-specific effect on transcriptional activity. The CATA sequence contributes to weaker promoter activity than a TATA box, but is able to interact with the upstream elements to increase the efficacy of an enhancer. The CATA box may thus be involved in the cell-specific and physiological regulation of the VP gene.