title: Identification, functional characterization and phylogenetic analysis of double stranded RNA degrading enzymes present in the gut of the desert locust, Schistocerca gregaria.
abstract: RNA interference (RNAi) has become a widely used reverse genetics tool in eukaryotes and holds great potential to contribute to the development of novel strategies for insect pest control. While previous studies clearly demonstrated that injection of dsRNA into the body cavity of the desert locust, Schistocerca gregaria, is highly effective to induce gene silencing effects, we observed that the RNAi response is much less sensitive to orally delivered dsRNA. In line with this, we report on the presence of a potent dsRNA degrading activity in the midgut juice. Four different dsRNase sequences that belong to the DNA/RNA Non-specific Nuclease superfamily were retrieved from a transcriptome database of the desert locust. Surprisingly, we have found that, in the publicly available eukaryote nucleotide sequence databases, the presence of this group of enzymes is restricted to insects and crustaceans. Nonetheless, phylogenetic analyses predict a common origin of these enzymes with the Endonuclease G (EndoG) Non-specific Nucleases that display a widespread taxonomic distribution. Moreover, in contrast to the Sg-endoG transcript, the four Sg-dsRNase transcripts appear to be specifically expressed in the gut. Finally, by means of RNAi, we provide evidence for an important contribution of dsRNase2 to the dsRNA degrading activity that is present in the gut lumen of S. gregaria.
authors.affiliation: Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, P.O. Box 02465, B-3000 Leuven, Belgium. Electronic address: Niels.Wynant@bio.kuleuven.be.
authors.forename: Niels
authors.initials: N
authors.lastname: Wynant
authors.affiliation: Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, P.O. Box 02465, B-3000 Leuven, Belgium.
authors.forename: Dulce
authors.initials: D
authors.lastname: Santos
authors.affiliation: Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, P.O. Box 02465, B-3000 Leuven, Belgium.
authors.forename: Rik
authors.initials: R
authors.lastname: Verdonck
authors.affiliation: Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, P.O. Box 02465, B-3000 Leuven, Belgium.
authors.forename: Jornt
authors.initials: J
authors.lastname: Spit
authors.affiliation: Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, P.O. Box 02465, B-3000 Leuven, Belgium.
authors.forename: Pieter
authors.initials: P
authors.lastname: Van Wielendaele
authors.affiliation: Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, P.O. Box 02465, B-3000 Leuven, Belgium.
authors.forename: Jozef
authors.initials: J
authors.lastname: Vanden Broeck
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D005260:Female; D041981:Gastrointestinal Tract / Q000201:enzymology; D020868:Gene Silencing; D006110:Grasshoppers / Q000145:classification* / Q000201:enzymology* / Q000235:genetics; D019476:Insect Proteins / Q000235:genetics* / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny; D012330:RNA, Double-Stranded; D060888:Real-Time Polymerase Chain Reaction; D016415:Sequence Alignment
chemical_list: D019476:Insect Proteins; D012330:RNA, Double-Stranded
keywords: Digestion; Endonuclease G (endoG); Insect; Nuclease; RNA interference (RNAi); White spot syndrome virus; dsRNA; dsRNase