MUTATIONS IN BACILLUS SUBTILIS PYRR, THE PYR REGULATORY PROTEIN, WITH DEFECTS IN REGULATION BY PYRIMIDINES

摘要

The pyrimidine nucleotide biosynthetic (pyr) operon in Bacillus subtilis is regulated by a transcriptional attenuation mechanism in which PyrR, a bifunctional pyr RNA-binding attenuation protein/uracil phosphoribosyltransferase, plays a crucial role. A convenient procedure for isolation of pyrR mutants with defects in the regulation of pyr operon expression is described, The selection is based on the selection of spontaneous mutations that convert the pyrimidine-sensitive growth of cpn strain (lacking arginine-repressible carbamyl phosphate synthetase) to pyrimidine resistance. Twelve such mutants were isolated and sequenced. All resulted from point mutations in the pyrR gene. [References: 20]