title: Knockdown of the Rhipicephalus microplus cytochrome c oxidase subunit III gene is associated with a failure of Anaplasma marginale transmission.
abstract: Rhipicephalus microplus is an obligate hematophagous ectoparasite of cattle and an important biological vector of Anaplasma marginale in tropical and subtropical regions. The primary determinants for A. marginale transmission are infection of the tick gut, followed by infection of salivary glands. Transmission of A. marginale to cattle occurs via infected saliva delivered during tick feeding. Interference in colonization of either the tick gut or salivary glands can affect transmission of A. marginale to naïve animals. In this study, we used the tick embryonic cell line BME26 to identify genes that are modulated in response to A. marginale infection. Suppression-subtractive hybridization libraries (SSH) were constructed, and five up-regulated genes {glutathione S-transferase (GST), cytochrome c oxidase sub III (COXIII), dynein (DYN), synaptobrevin (SYN) and phosphatidylinositol-3,4,5-triphosphate 3-phosphatase (PHOS)} were selected as targets for functional in vivo genomic analysis. RNA interference (RNAi) was used to determine the effect of tick gene knockdown on A. marginale acquisition and transmission. Although RNAi consistently knocked down all individually examined tick genes in infected tick guts and salivary glands, only the group of ticks injected with dsCOXIII failed to transmit A. marginale to naïve calves. To our knowledge, this is the first report demonstrating that RNAi of a tick gene is associated with a failure of A. marginale transmission.
authors.affiliation: Department of Parasitology, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brazil; Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, United States of America.
authors.forename: Thais D
authors.initials: TD
authors.lastname: Bifano
authors.affiliation: Animal Diseases Research Unit, USDA-ARS, Pullman, Washington United States of America.
authors.forename: Massaro W
authors.initials: MW
authors.lastname: Ueti
authors.affiliation: Department of Parasitology, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brazil.
authors.forename: Eliane
authors.initials: E
authors.lastname: Esteves
authors.affiliation: Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, United States of America.
authors.forename: Kathryn E
authors.initials: KE
authors.lastname: Reif
authors.affiliation: Department of Biochemistry, Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, Rio de Janeiro, RJ, Brazil.
authors.forename: Glória R C
authors.initials: GR
authors.lastname: Braz
authors.affiliation: Animal Diseases Research Unit, USDA-ARS, Pullman, Washington United States of America.
authors.forename: Glen A
authors.initials: GA
authors.lastname: Scoles
authors.affiliation: Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, United States of America.
authors.forename: Reginaldo G
authors.initials: RG
authors.lastname: Bastos
authors.affiliation: Animal Diseases Research Unit, USDA-ARS, Pullman, Washington United States of America.
authors.forename: Stephen N
authors.initials: SN
authors.lastname: White
authors.affiliation: Department of Parasitology, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brazil; Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, Rio de Janeiro, RJ, Brazil.
authors.forename: Sirlei
authors.initials: S
authors.lastname: Daffre
mesh_terms: D042322:Anaplasma marginale / Q000235:genetics*; D000712:Anaplasmosis / Q000235:genetics / Q000382:microbiology / Q000635:transmission*; D000818:Animals; D002417:Cattle; D002460:Cell Line; D003576:Electron Transport Complex IV / Q000235:genetics*; D015870:Gene Expression / Q000235:genetics; D034622:RNA Interference; D048494:Rhipicephalus / Q000235:genetics*; D012469:Salivary Glands / Q000382:microbiology; D013987:Ticks / Q000382:microbiology*
chemical_list: D003576:Electron Transport Complex IV