The analysis of cell division and cell wall synthesis genes reveals mutationally inactivated ftsQ and mraY in a protoplast-type L-form of Escherichia coli

FEMS Microbiol Lett. 2006 May;258(2):305-11. doi: 10.1111/j.1574-6968.2006.00237.x.


Cell division and cell wall synthesis are tightly linked cellular processes for bacterial growth. A protoplast-type L-form Escherichia coli, strain LW1655F+, indicated that bacteria can divide without assembling a cell wall. However, the molecular basis of its phenotype remained unknown. To establish a first phenotype-genotype correlation, we analyzed its dcw locus, and other genes involved in division of E. coli. The analysis revealed defective ftsQ and mraY genes, truncated by a nonsense and a frame-shift mutation, respectively. Missense mutations were determined in the ftsA and ftsW products yielding amino-acid replacements at conserved positions. FtsQ and MraY, obviously nonfunctional in the L-form, are essential for cell division and cell wall synthesis, respectively, in all bacteria with a peptidoglycan-based cell wall. LW1655F+ is able to survive their loss-of-functions. This points to compensatory mechanisms for cell division in the absence of murein sacculus formation. Hence, this L-form represents an interesting model to investigate the plasticity of cell division in E. coli, and to demonstrate how concepts fundamental for bacterial life can be bypassed.

MeSH terms

  • Amino Acid Sequence
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics*
  • Bacterial Proteins / physiology
  • Cell Division / genetics*
  • Cell Division / physiology
  • Cell Wall / genetics*
  • Cell Wall / metabolism
  • Cell Wall / ultrastructure
  • Codon, Nonsense
  • Escherichia coli / classification
  • Escherichia coli / cytology
  • Escherichia coli / genetics*
  • Escherichia coli Proteins / chemistry
  • Escherichia coli Proteins / genetics*
  • Escherichia coli Proteins / physiology
  • Frameshift Mutation
  • Membrane Proteins / chemistry
  • Membrane Proteins / genetics*
  • Membrane Proteins / physiology
  • Molecular Sequence Data
  • Protoplasts / metabolism
  • Sequence Alignment
  • Sequence Analysis, DNA
  • Transferases (Other Substituted Phosphate Groups)
  • Transferases / chemistry
  • Transferases / genetics*
  • Transferases / physiology


  • Bacterial Proteins
  • Codon, Nonsense
  • Escherichia coli Proteins
  • FtsQ protein, E coli
  • Membrane Proteins
  • Transferases
  • Transferases (Other Substituted Phosphate Groups)
  • mraY protein, Bacteria