Molecular models to analyse preprotachykinin-A expression and function

Towards an understanding of the mechanisms controlling Preprotachykinin A ( PPT) expression we have generated a variety of molecular models to determin e the mechanisms regulating both the tissue-specific and stimulus-inducible expression of the PPT gene. The approaches used include transgenic and vir us vector models complementing biochemical analysis of promoter interaction s with transcription factors. We have identified and characterised a yeast artificial chromosome (YAC) containing the human PPT gene and generated tra nsgenic mouse lines containing multiple copies of this chromosome on a norm al mouse genetic background. This resulted in a pattern of expression in th e nervous system remarkably similar to that reported for PPT mRNA in rodent s. In addition, this transgenic model has been constructed in such a manner to allow for over expression of tachykinins based on the number of extra a lleles in the transgenic mouse. These animals allow us to further examine t he function of the tachykinins and acts as a useful complement to existing PPT ablated mice. In vitro we have introduced the proximal PPT promoter in reporter gene constructs into adult neurones in both DRG and the CNS by an adenoassociated virus (AAV) vector or by biolistic transfection respectivel y. Using the AAV vector we have demonstrated that the proximal promoter can mediate the effects of NGF in adult rat DRG. These models allow us to deli neate transcriptional domains involved in the physiological and pathologica l expression of the PPT gene. (C) 2000 Harcourt Publishers Ltd.