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.
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.
Siddiqui
Roman A
RA
Leibniz Institute for Age Research, Jena, Germany. rsidd@fli-leibniz.de
Hoischen
Christian
C
Holst
Otto
O
Heinze
Ivonne
I
Schlott
Bernhard
B
Gumpert
Johannes
J
Diekmann
Stephan
S
Grosse
Frank
F
Platzer
Matthias
M
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D002455:Cell Division / Q000235:genetics* / Q000502:physiology; D002473:Cell Wall / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure; D018389:Codon, Nonsense; D004926:Escherichia coli / Q000145:classification / Q000166:cytology / Q000235:genetics*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D016368:Frameshift Mutation; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D008969:Molecular Sequence Data; D011523:Protoplasts / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D014166:Transferases / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D017855:Transferases (Other Substituted Phosphate Groups)
D001426:Bacterial Proteins; D018389:Codon, Nonsense; D029968:Escherichia coli Proteins; C068023:FtsQ protein, E coli; D008565:Membrane Proteins; D014166:Transferases; D017855:Transferases (Other Substituted Phosphate Groups); C079803:mraY protein, Bacteria