A Genetic Study of the Stringent Response
When a bacterial cell is starved for amino acids the stringent factor is produced by the relA gene. The stringent factor is the production of two guanosine nucleotides, which are degraded by the product of the spoT gene. The spoT gene is located within the spoT locus, which contains two promoters and six open reading frames (orf). The 2 orf contains the spoT gene. The 1.5 orf was genetically tested to find if the 1.5 orf was essential in connection with the stringent response. First the 1.5 orf was inserted with a kanamycin element, which is an antibiotic. Theses plasmids were transformed into competent cells and lysates were made of them. Lysogens were made from these lysates with different magnesium starved strains containing a wild type of a severe mutation of the spoT gene. These lysogens were cured to test if 1.5 orf was an essential gene. Wild type strains cured above the 1% mark and severely mutated strains cured much below the 1% mark. These results suggest that the 1.5 orf is an essential gene when the spoT gene is severely mutated.