Cytokinesis of Trypanosoma brucei bloodstream forms depends on expression of adenylyl cyclases of the ESAG4 or ESAG4-like subfamily

Authors

  • Didier Salmon,

    Corresponding author
    1. Laboratory of Molecular Parasitology, Institute of Molecular Biology and Medicine, Université Libre de Bruxelles, 12, rue des Professeurs Jeener et Brachet, B-6041 Gosselies, Belgium
      E-mail salmon@bioqmed.ufrj.br; Tel. (+55) 21 25626756; Fax (+55) 21 38814155.
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    • Present addresses: Institute of Medical Biochemistry, Centro de Ciências e da Saude, Federal University of Rio de Janeiro, Av. General Trompowsky, Rio de Janeiro, 21941-590, Brazil;

  • Sabine Bachmaier,

    1. Biocenter, Section Genetics, University of Munich (LMU), Grosshaderner Str. 2-4, D-82152 Martinsried, Germany
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  • Carsten Krumbholz,

    1. Biocenter, Section Genetics, University of Munich (LMU), Grosshaderner Str. 2-4, D-82152 Martinsried, Germany
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    • Human GmbH, Berlin, Germany.

  • Markus Kador,

    1. Biocenter, Section Genetics, University of Munich (LMU), Grosshaderner Str. 2-4, D-82152 Martinsried, Germany
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  • Jasmin A. Gossmann,

    1. Biocenter, Section Genetics, University of Munich (LMU), Grosshaderner Str. 2-4, D-82152 Martinsried, Germany
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  • Pierrick Uzureau,

    1. Laboratory of Molecular Parasitology, Institute of Molecular Biology and Medicine, Université Libre de Bruxelles, 12, rue des Professeurs Jeener et Brachet, B-6041 Gosselies, Belgium
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  • Etienne Pays,

    1. Laboratory of Molecular Parasitology, Institute of Molecular Biology and Medicine, Université Libre de Bruxelles, 12, rue des Professeurs Jeener et Brachet, B-6041 Gosselies, Belgium
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    • These authors contributed equally to this work.

  • Michael Boshart

    Corresponding author
    1. Biocenter, Section Genetics, University of Munich (LMU), Grosshaderner Str. 2-4, D-82152 Martinsried, Germany
      E-mail boshart@lmu.de; Tel. (+49) 89 2180 74600; Fax (+49) 89 2180 74629;
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    • These authors contributed equally to this work.


E-mail boshart@lmu.de; Tel. (+49) 89 2180 74600; Fax (+49) 89 2180 74629;

E-mail salmon@bioqmed.ufrj.br; Tel. (+55) 21 25626756; Fax (+55) 21 38814155.

Summary

Antigenic variation of the parasite Trypanosoma brucei operates by monoallelic expression of a variant surface glycoprotein (VSG) from a collection of multiple telomeric expression sites (ESs). Each of these ESs harbours a long polycistronic transcription unit containing several expression site-associated genes (ESAGs). ESAG4 copies encode bloodstream stage-specific adenylyl cyclases (AC) and belong to a larger gene family of around 80 members, the majority of which, termed genes related to ESAG4 (GRESAG4s), are not encoded in ESs and are expressed constitutively in the life cycle. Here we report that ablation of ESAG4 from the active ES did not affect parasite growth, neither in culture nor upon rodent infection, and did not significantly change total AC activity. In contrast, inducible RNAi-mediated knock-down of an AC subfamily that includes ESAG4 and two ESAG4-like GRESAG4 (ESAG4L) genes, decreased total AC activity and induced a lethal phenotype linked to impaired cytokinesis. In the Δesag4 line compensatory upregulation of apparently functionally redundant ESAG4L genes was observed, suggesting that the ESAG4/ESAG4L-subfamily ACs are involved in the control of cell division. How deregulated adenylyl cyclases or cAMP might impair cytokinesis is discussed.

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