THE UMPA GENE OF ESCHERICHIA-COLI ENCODES PHOSPHATIDYLGLYCEROL-PROLIPOPROTEIN DIACYLGLYCERYL TRANSFERASE (LGT) AND REGULATES THYMIDYLATE SYNTHASE LEVELS THROUGH TRANSLATIONAL COUPLING

Using a combination of biochemical, physical, and genetic techniques, we have shown that the umpA gene of Escherichia coli is allelic with t he lgt (phosphatidylglycerol:prolipoprotein diacylglyceryl transferase ) of Salmonella typhimurium. These genes are essential for the viabili ty of the respective organism and exhibit 92.8% sequence identity at t he amino acid level. In E. coli, lgt and thyA (thymidylate synthase) f orm an operon. Thymidylate synthase levels are regulated by transcript ion from the lgt promoter and by translational coupling.