Identification of phosphate-regulated genes by differential expression in the UV-irradiated host system

The UV-irradiated host system has been used for identifying protein products of genes cloned in a phage vector. By starving the host cells for phosphate immediately before UV-irradiation, we demonstrate that phosphate-regulated genes can be easily identified. By employing this new technique, we also provide evidence showing that the gpsA gene might be a new member of the phosphate starvation-inducible (psi) genes of E. coli.