Co-ordination between membrane oriC sequestration factors and a chromosome partitioning protein, TolC (MukA)

• Published in: Molecular microbiology Vol. 22; no. 2; p. 275
• Main Authors: Bahloul, A, Meury, J, Kern, R, Garwood, J, Guha, S, Kohiyama, M
• Format: Journal Article
• Language: English
• Published: England 01-10-1996
• Subjects: Bacterial Outer Membrane Proteins - genetics; Bacterial Outer Membrane Proteins - metabolism; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Cell Membrane - metabolism; Chromosomes, Bacterial - metabolism; DNA Footprinting; DNA Methylation; DNA, Bacterial - metabolism; DNA-Binding Proteins; Down-Regulation; Escherichia coli - genetics; Escherichia coli - metabolism; Escherichia coli Proteins; Membrane Transport Proteins; Mutation; Osmotic Pressure; Replication Origin; Transcription Factors
• ISSN: 0950-382X
• DOI: 10.1046/j.1365-2958.1996.00106.x

oriC DNA in the hemimethylated (but not in the fully methylated) state reacts with an Escherichia coli K-12 outer membrane preparation. This reaction is drastically reduced when the membrane preparation of a seqA null mutant is used. An in vitro reconstitution of the activity was undertaken by adding a partially purified SeqA protein to a seqA mutant membrane without success. A possible reason for this failure might be a profound modification of the outer membrane of the seqA mutant (as revealed by the fact that membrane from the mutant sediments more slowly than that from the wild type during ultracentrifugation). There is also a reduction in the content of OmpF protein. Moreover, one of the minor outer membrane proteins involved in partitioning of newly synthesized chromosomes, the ToiC (MukA) protein, was also found to be downregulated in the seqA mutant. This is also true of the hobH mutant grown in a high-osmolarity medium. Mutants of both seqA and hobH stop dividing after hyperosmotic shock, forming filaments (as observed in dam mutants).