title: Role of micF in the tolC-mediated regulation of OmpF, a major outer membrane protein of Escherichia coli K-12.
abstract: Mutation in the tolC locus greatly reduces normal synthesis of OmpF, a major porin protein of Escherichia coli K-12. Experiments that use ompF-ompC chimeric genes demonstrate that a tolC mutation exerts its effect at either the promoter or the amino-terminal end of the ompF gene. Direct analysis of ompF mRNA from tolC+ and tolC strains showed that the amount of ompF transcript in the latter was greatly reduced. We have also observed that, in addition to reducing the amount of OmpF, a tolC mutation increases the level of OmpC protein to a much greater extent than occurs in an OmpF mutant and also increases micF RNA synthesis as shown by increased beta-galactosidase synthesis in a micF-lacZ fusion strain. Based on these observations, we suggest that an increased expression of the micF gene in a tolC mutant results in the reduced expression of ompF and that a major effect of the tolC mutation may be to push the porin-regulating system to favor ompC and micF to a greater extent than under high-osmolarity conditions.
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000096:biosynthesis / Q000235:genetics*; D003001:Cloning, Molecular; D003470:Culture Media; D004262:DNA Restriction Enzymes; D004269:DNA, Bacterial / Q000032:analysis; D004587:Electrophoresis, Agar Gel; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation; D005798:Genes, Bacterial; D005809:Genes, Regulator; D009154:Mutation; D009693:Nucleic Acid Hybridization; D009994:Osmolar Concentration; D010957:Plasmids; D012329:RNA, Bacterial / Q000032:analysis; D012333:RNA, Messenger / Q000032:analysis; D014158:Transcription, Genetic
chemical_list: D001425:Bacterial Outer Membrane Proteins; D003470:Culture Media; D004269:DNA, Bacterial; D012329:RNA, Bacterial; D012333:RNA, Messenger; D004262:DNA Restriction Enzymes