Identification and characterization of a gene that controls colony morphology and auto-aggregation in Escherichia coli K12

J Gen Microbiol. 1990 Mar;136(3):455-62. doi: 10.1099/00221287-136-3-455.


Many Escherichia coli K12 strains undergo switching between two forms which differ in a number of surface properties including colony morphology and the ability to auto-aggregate. This paper describes the identification of a gene which appears to play a part in controlling this switching phenomenon. This gene has been designated mor and is located at 89 minutes on the E. coli chromosome map between the argECBH operon and the trmA gene. By manipulation of this gene it is possible to overcome the switching of surface properties and fix a strain in one form or the other. The mor gene has been cloned and its DNA sequence determined. The putative protein sequence shows a high level of homology with four regulatory genes, the ilvY, cysB and lysR genes from E. coli and the metR gene from Salmonella typhimurium. It has also been shown that the mor gene is autoregulated at the transcriptional level.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Bacterial Adhesion / genetics*
  • Base Sequence
  • Chromosome Mapping
  • Cloning, Molecular
  • DNA Transposable Elements
  • DNA, Bacterial / analysis
  • DNA-Binding Proteins*
  • Escherichia coli / genetics*
  • Escherichia coli Proteins
  • Gene Expression Regulation, Bacterial*
  • Genes, Bacterial*
  • Molecular Sequence Data
  • Mutation
  • Operon
  • Phenotype
  • Repressor Proteins / genetics*
  • Sequence Homology, Nucleic Acid
  • Transcription Factors / genetics*


  • DNA Transposable Elements
  • DNA, Bacterial
  • DNA-Binding Proteins
  • Escherichia coli Proteins
  • Repressor Proteins
  • Transcription Factors
  • oxyR protein, E coli

Associated data

  • GENBANK/M34102