title: Tsetse salivary gland proteins 1 and 2 are high affinity nucleic acid binding proteins with residual nuclease activity.
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 K(D) 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.
authors.affiliation: Department of Biomedical Sciences, Unit of Veterinary Protozoology, Institute of Tropical Medicine Antwerp (ITM), Antwerp, Belgium. gcaljon@itg.be
authors.forename: Guy
authors.initials: G
authors.lastname: Caljon
authors.forename: Karin
authors.initials: K
authors.lastname: De Ridder
authors.forename: Benoît
authors.initials: B
authors.lastname: Stijlemans
authors.forename: Marc
authors.initials: M
authors.lastname: Coosemans
authors.forename: Stefan
authors.initials: S
authors.lastname: Magez
authors.forename: Patrick
authors.initials: P
authors.lastname: De Baetselier
authors.forename: Jan
authors.initials: J
authors.lastname: Van Den Abbeele
mesh_terms: D000818:Animals; D004720:Endonucleases / Q000235:genetics / Q000378:metabolism*; D020224:Expressed Sequence Tags; D006863:Hydrogen-Ion Concentration; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism*; D012469:Salivary Glands / Q000378:metabolism; D012471:Salivary Proteins and Peptides / Q000235:genetics / Q000378:metabolism*; D014370:Tsetse Flies / Q000201:enzymology* / Q000378:metabolism*
chemical_list: D019476:Insect Proteins; D012471:Salivary Proteins and Peptides; D004720:Endonucleases