Work has been carried out on the intraction between the areA gene mediating nitrogen metabolite repression in Aspergillus nidulans and specific regulatory genes (eg PrnA, nirA, uaY). The areA gene has been sequenced and has a deoxyribonucleic acid (DNA) binding region of 52 residues. A region of 224 residues has been lined to gene activation and includes the DNA binding region and a highly acidic region. Loss of function mutations have been identified and reversion of these mutations has been used to identify inessential residues. The C-terminus is essential for expression of only a few genes under areA control. The regulatory genes prnA, nirA and uaY have been sequenced and DNA binding sites identified. Investigations of cis acting regions have been carried out and have provided further information on the niaD (nitrate) and niiA (nitride) cluster, the uapA (urate scanthine permease) gene, the prn (proline) gene and structural genes belonging to the purine and proline utilisation pathways.
Focusing on three important pathways of nitrogen metabolism subject to both specific induction and nitrogen metabolite repression in the fungus Aspergillus nidulans, we shall analyse, using classical and reverse genetics and in vitro studies, the mechanism by which the respective pathway-specific regulatory genes and the wide domain regulatory gene areA (mediating nitrogen metabolite repression) effect structural gene expression. The involvement of the cryptic regulatory gene areB, which can substitute for areA, will also be analysed.
Funding SchemeCSC - Cost-sharing contracts
W12 ONN London