Proteins encoded by the mre gene cluster in Streptomyces coelicolor A3(2) cooperate in spore wall synthesis

Authors

  • Eva-Maria Kleinschnitz,

    1. Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Tübingen IMIT, Mikrobiologie/Biotechnologie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Deutschland.
    Search for more papers by this author
    • Both authors contributed equally.

  • Andrea Heichlinger,

    1. Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Tübingen IMIT, Mikrobiologie/Biotechnologie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Deutschland.
    Search for more papers by this author
    • Both authors contributed equally.

  • Kathrin Schirner,

    1. Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Tübingen IMIT, Mikrobiologie/Biotechnologie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Deutschland.
    Search for more papers by this author
    • Present address: Department of Microbiology and Molecular Genetics, Harvard Medical School, 200 Longwood Avenue, Boston, MA02115, USA.

  • Juliane Winkler,

    1. Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Tübingen IMIT, Mikrobiologie/Biotechnologie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Deutschland.
    Search for more papers by this author
    • Present address: Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Deutschland.

  • Annette Latus,

    1. Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Tübingen IMIT, Mikrobiologie/Biotechnologie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Deutschland.
    Search for more papers by this author
  • Iris Maldener,

    1. Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Tübingen IMIT, Organismische Interaktionen, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany.
    Search for more papers by this author
  • Wolfgang Wohlleben,

    1. Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Tübingen IMIT, Mikrobiologie/Biotechnologie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Deutschland.
    Search for more papers by this author
  • Günther Muth

    Corresponding author
    1. Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Tübingen IMIT, Mikrobiologie/Biotechnologie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Deutschland.
    Search for more papers by this author

E-mail gmuth@biotech.uni-tuebingen.de; Tel. +4970712974637; Fax +497071295979.

Summary

It is still an open question how an intracellular cytoskeleton directs the synthesis of the peptidoglycan exoskeleton. In contrast to MreB of rod-shaped bacteria, which is essential for lateral cell wall synthesis, MreB of Streptomyces coelicolor has a role in sporulation. To study the function of the S. coelicolor mre gene cluster consisting of mreB, mreC, mreD, pbp2 and sfr, we generated non-polar replacement mutants. The individual mutants were viable and growth of substrate mycelium was not affected. However, all mutants produced enlarged spores, which frequently germinated prematurely and were sensitive to heat, high osmolarity and cell wall damaging agents. Protein–protein interaction assays by bacterial two-hybrid analyses indicated that the S. coelicolor Mre proteins form a spore wall synthesizing complex, which closely resembles the lateral wall synthesizing complex of rod-shaped bacteria. Screening of a genomic library identified several novel putative components of this complex. One of them (sco2097) was deleted. The Δsco2097 mutant formed sensitive spores with an aberrant morphology, demonstrating that SCO2097 is a new player in cell morphogenesis of Streptomyces. Our results suggest that all Mre proteins cooperate with the newly identified proteins in the synthesis of the thickened spore wall required to resist detrimental environmental conditions.

Ancillary