NEURON-SPECIFIC EXPRESSION AND PHYSIOLOGICAL REGULATION OF BOVINE VASOPRESSIN TRANSGENES IN MICE

We have used transgenic mice to analyse the regulation of the bovine v asopressin (BVP) gene. We rind that the restriction of BVP gene expres sion to anatomically and functionally distinct hypothalamic neuronal g roups is achieved, in part, by selective repression. The expression of a 1.25 kb BVP proximal promoter, which on its own confers general exp ression of a reporter to most peripheral and brain tissues, was limite d by sequences in the BVP structural gene to neural cells in the adren al medulla and brain. Transgene expression in the hypothalamus was sho wn to be regulated by the physiological stimulus of dehydration in par allel with the endogenous gene. The expression of a larger 13.4 kb BVP transgene, containing 9 kb of 5' upstream sequence, the VP structural gene and 1.5 kb 3' of the transcription unit, was even more restricte d and resembles that of the endogenous mouse gene. Hypothalamic expres sion of the 13.4 kb BVP transgene was regulated appropriately in respo nse to an osmotic challenge.