Involvement of an essential gene, mviN, in murein synthesis in Escherichia coli

Abstract

We isolated a temperature-sensitive mutant with a mutation in mviN, an essential gene in Escherichia coli. At the nonpermissive temperature, mviN mutant cells swelled and burst. An intermediate in murein synthesis, polyprenyl diphosphate-N-acetylmuramic acid-(pentapeptide)-N-acetyl-glucosamine, accumulated in mutant cells. These results indicated that MviN is involved in murein synthesis.

FIG. 1.

Sequence of the mviN^ts555 TS mutation. mviN^ts555 mutants had a deletion that extended from the NruI site of yceH (nucleotide 429 of the open reading frame) to the upstream region of mviN (nucleotide −57 relative to the initiation codon at nucleotide 1). Lowercase letters indicate open reading frame sequences. The termination codon of yceH and the initiation codon of mviN are underlined. The underlined uppercase letters indicate the promoter of mviN.

FIG. 2.

Cell morphology of mviN^ts555. (A) Wild-type mviN⁺ strain [strain MG1655 ΔmviN::Sm recA::Tn10/mini-F (Ap^r)-mviN⁺]; (B) TS mviN^ts555 mutant [strain MG1655 ΔmviN::Sm recA::Tn10/mini-F (Ap^r)-mviN^ts555]. Cells were incubated at 42°C for 2 h and observed without fixation by using phase-contrast microscopy. Magnification, ×100. The arrows indicate ghosts.