Determination of bacterial rod shape by a novel cytoskeletal membrane protein

Authors

  • Daisuke Shiomi,

    1. Microbial Genetics Laboratory, Genetic Strains Research Center, National Institute of Genetics, Mishima, Japan
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  • Masako Sakai,

    1. Microbial Genetics Laboratory, Genetic Strains Research Center, National Institute of Genetics, Mishima, Japan
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  • Hironori Niki

    Corresponding author
    1. Microbial Genetics Laboratory, Genetic Strains Research Center, National Institute of Genetics, Mishima, Japan
    2. Department of Genetics, The Graduate University for Advanced Studies, Mishima (SOKENDAI), Shizuoka, Japan
    • Corresponding author. Microbial Genetics Laboratory, Genetic Strain Research Center, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka 411-8540, Japan. Tel.: +81 55 981 6870; Fax: +81 55 981 6826; E-mail: hniki@lab.nig.ac.jp

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Abstract

Cell shape is critical for growth, and some genes are involved in bacterial cell morphogenesis. Here, we report a novel gene, rodZ, required for the determination of rod shape in Escherichia coli. Cells lacking rodZ no longer had rod shape but rather were round or oval. These round cells were smaller than known round mutant cells, including mreB and pbpA mutants; both are known to lose rod shape. Morphogenesis from rod cells to round cells and vice versa, caused by depletion and overproduction of RodZ, respectively, revealed that RodZ could regulate the length of the long axis of the cell. RodZ is a membrane protein with bitopic topology such that the N-terminal region including a helix-turn-helix motif is in the cytoplasm, whereas the C-terminal region is exposed in the periplasm. GFP–RodZ forms spirals along the lateral axis of the cell beneath the cell membrane, similar to the MreB bacterial actin. Thus, RodZ may mediate spatial information from cytoskeletal proteins in the cytoplasm to a peptidoglycan synthesis machinery in the periplasm.

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