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  • The EMBO Journal (2007) 26, 1444 - 1455
  • doi:10.1038/sj.emboj.7601577

Published online: 15 February 2007

The asymmetric distribution of the essential histidine kinase PdhS indicates a differentiation event in Brucella abortus

Régis Hallez1,a, Johann Mignolet1, Vincent Van Mullem1, Maxime Wery1, Jean Vandenhaute1, Jean-Jacques Letesson1, Christine Jacobs-Wagner2 and Xavier De Bolle1

  1. Unité de Recherche en Biologie Moléculaire (URBM), University of Namur (FUNDP), Namur, Belgium
  2. Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT, USA

Correspondence to:

Xavier De Bolle, Unité de Recherche en Biologie Moléculaire (URBM), University of Namur (FUNDP), 61 rue de Bruxelles, 5000 Namur, Belgium. Tel.: +32 81 72 44 38; Fax: +32 81 72 42 97; E-mail: xavier.debolle@fundp.ac.be

aPresent address: Laboratoire de Génétique des Procaryotes (LGP), Institut de Biologie et de Médecine Moléculaires (IBMM), Université Libre de Bruxelles (ULB), 12 Rue des Professeurs Jeener et Brachet, 6041 Gosselies, Belgium

Received 6 November 2006; Accepted 8 January 2007

Many organisms use polar localization of signalling proteins to control developmental events in response to completion of asymmetric cell division. Asymmetric division was recently reported for Brucella abortus, a class III facultative intracellular pathogen generating two sibling cells of slightly different size. Here we characterize PdhS, a cytoplasmic histidine kinase essential for B. abortus viability and homologous to the asymmetrically distributed PleC and DivJ histidine kinases from Caulobacter crescentus. PdhS is localized at the old pole of the large cell, and after division and growth, the small cell acquires PdhS at its old pole. PdhS may therefore be considered as a differentiation marker as it labels the old pole of the large cell. Moreover, PdhS colocalizes with its paired response regulator DivK. Finally, PdhS is able to localize at one pole in other alpha-proteobacteria, suggesting that a polar structure associating PdhS with one pole is conserved in these bacteria. We propose that a differentiation event takes place after the completion of cytokinesis in asymmetrically dividing alpha-proteobacteria. Altogether, these data suggest that prokaryotic differentiation may be much more widespread than expected.

  • Keywords:

    • asymmetry,
    • Brucella,
    • Caulobacter,
    • differentiation,
    • polar localization