Molecular Cloning and Expression of a Hexamerin cDNA from the Malaria Mosquito, Anopheles Gambiae

Authors

  • Stanislav O. Zakharkin,

    1. Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, USA
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  • Alexey V. Gordadze,

    1. Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, USA
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  • Svetlana E. Korochkina,

    1. Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, USA
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  • Kostas D. Mathiopoulos,

    1. Istituto di Parassitologia, Fondazione ‘Pasteur Cenci-Bolognetti’, Università di Roma ‘La Sapienza’, Rome, Italy
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  • Alessandra Della Torre,

    1. Istituto di Parassitologia, Fondazione ‘Pasteur Cenci-Bolognetti’, Università di Roma ‘La Sapienza’, Rome, Italy
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  • Helen Beneš

    Corresponding author
    1. Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, USA
      H. Beneš, Department of Biochemistry/Molecular Biology, University of Arkansas for Medical Sciences, Slot 516, 4301 West Markham St., Little Rock, AR 72205, USA
      Fax: +1 501 6868169.
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H. Beneš, Department of Biochemistry/Molecular Biology, University of Arkansas for Medical Sciences, Slot 516, 4301 West Markham St., Little Rock, AR 72205, USA
Fax: +1 501 6868169.

Abstract

During the last larval instar, dipteran insects synthesize two hexamerins rich in aromatic residues, typified by the larval serum proteins 1 and 2 (LSP-1 and LSP-2) of Drosophila melanogaster. We report here the characterization of a complete cDNA sequence encoding a LSP-1-like protein from a lower dipteran insect, the malaria mosquito Anopheles gambiae. The cDNA encodes the subunit of a homohexamer, A. gambiae hexamerin-1.1 (AgHex-1.1), which is a major pupal protein but only a minor constituent of late larval hemolymph. AgHex-1.1 is moderately rich in methionine (3.9%) and particularly rich in aromatic residues (21% Phe + Tyr). Cytogenetic analysis reveals AgHex-1.1 to be encoded by a single-copy gene localized to division 22F within the proximal 2La inversion breakpoint of chromosome 2 of A. gambiae. The AgHex-1.1 transcript is first detected in fourth-instar larvae (L4) and disappears abruptly in early pupae. In situ hybridization shows accumulation of the transcript uniquely in the larval fat body. AgHex-1.1 mRNA is re-expressed in male and female adults at about 10% of the L4 level, with no effect of bloodfeeding in females. The potential roles of AgHex-1.1 in Anopheles development and reproductive maturation are discussed.

Abbreviations.
AgHex-1.1

hexamerin-1.1 of Anopheles gambiae

L4 larvae

fourth-instar larvae

LSP

larval serum protein

Ancillary