Tsetse Salivary Gland Proteins 1 and 2 Are High Affinity Nucleic Acid Binding Proteins with Residual Nuclease Activity |
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| Authors: | Guy Caljon Karin De Ridder Beno?t Stijlemans Marc Coosemans Stefan Magez Patrick De Baetselier Jan Van Den Abbeele |
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| Institution: | 1. Department of Biomedical Sciences, Unit of Veterinary Protozoology, Institute of Tropical Medicine Antwerp (ITM), Antwerp, Belgium.; 2. Unit of Cellular and Molecular Immunology, Vrije Universiteit Brussel (VUB), Brussels, Belgium.; 3. Laboratory of Myeloid Cell Immunology, VIB, Brussels, Belgium.; 4. Department of Biomedical Sciences, Unit of Medical Entomology, Institute of Tropical Medicine Antwerp (ITM), Antwerp, Belgium.; Metabiota, United States of America, |
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| Abstract: | Analysis of the tsetse fly salivary gland EST database revealed the presence of a highly enriched cluster of putative endonuclease genes, including tsal1 and tsal2. Tsal proteins are the major components of tsetse fly (G. morsitans morsitans) saliva where they are present as monomers as well as high molecular weight complexes with other saliva proteins. We demonstrate that the recombinant tsetse salivary gland proteins 1&2 (Tsal1&2) display DNA/RNA non-specific, high affinity nucleic acid binding with KD values in the low nanomolar range and a non-exclusive preference for duplex. These Tsal proteins exert only a residual nuclease activity with a preference for dsDNA in a broad pH range. Knockdown of Tsal expression by in vivo RNA interference in the tsetse fly revealed a partially impaired blood digestion phenotype as evidenced by higher gut nucleic acid, hematin and protein contents. |
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