ISOLATION AND CHARACTERIZATION OF THE HEAT-RESPONSIVE GENES IN ESCHERICHIA-COLI

The ompC gene expression is induced by increasing temperature as well as osmotic pressure, In this study, a mutant (TD2) defective in this t hermoresponse was isolated with transposon Tn10; the mutation was comp lemented by pMAN55 or pMAN56 containing micF and mapped at 48 min on E scherichia coli K-12, Furthermore, a new gene (hrsA) that suppressed t he mutation was cloned. Its nucleotide sequence was analyzed and it wa s located close to the suc operon at 16.7 min corresponding to #18F11 (Kohara bank) on E. coli genome, In TD2 containing the hrsA on a multi copy plasmid, the ompC expression was induced and dependent on OmpR wi th increased temperature, The HrsA was found to have Enzyme IIB, IIB, and IIC domains that are homologous to Enzyme II, involved in the fruc tose-specific PTS (phosphotransferase system), The putative phosphoryl ation sites (His87 and Cys192) were also conserved in HrsA.