title: Effects of chitin synthase double-stranded RNA on molting and oogenesis in the Chagas disease vector Rhodnius prolixus.
abstract: In this study, we provided the demonstration of the presence of a single CHS gene in the Rhodnius prolixus (a blood-sucking insect) genome that is expressed in adults (integument and ovary) and in the integument of nymphs during development. This CHS gene appears to be essential for epidermal integrity and egg formation in R. prolixus. Because injection of CHS dsRNA was effective in reducing CHS transcript levels, phenotypic alterations in the normal course of ecdysis occurred. In addition, two phenotypes with severe cuticle deformations were observed, which were associated with loss of mobility and lifetime. The CHS dsRNA treatment in adult females affected oogenesis, reducing the size of the ovary and presenting a greater number of atresic oocytes and a smaller number of chorionated oocytes compared with the control. The overall effect was reduced oviposition. The injection of CHS dsRNA modified the natural course of egg development, producing deformed eggs that were dark in color and unable to hatch, distinct from the viable eggs laid by control females. The ovaries, which were examined under fluorescence microscopy using a probe for chitin detection, showed a reduced deposition on pre-vitellogenic and vitellogenic oocytes compared with control. Taken together, these data suggest that the CHS gene is fundamentally important for ecdysis, oogenesis and egg hatching in R. prolixus and also demonstrated that the CHS gene is a good target for controlling Chagas disease vectors.
authors.affiliation: Universidade Federal do Rio de Janeiro, Instituto de Química, 21941-909 Rio de Janeiro, RJ, Brazil.
authors.forename: Juliana F
authors.initials: JF
authors.lastname: Mansur
authors.affiliation: Universidade Federal do Rio de Janeiro, Instituto de Química, 21941-909 Rio de Janeiro, RJ, Brazil.
authors.forename: Evelyn S L
authors.initials: ES
authors.lastname: Alvarenga
authors.affiliation: Universidade Federal do Rio de Janeiro, Instituto de Química, 21941-909 Rio de Janeiro, RJ, Brazil; Universidade Federal do Rio de Janeiro, Instituto de Bioquímica Médica, Programa de Biologia Molecular e Biotecnologia, 21941-902 Rio de Janeiro, RJ, Brazil.
authors.forename: Janaina
authors.initials: J
authors.lastname: Figueira-Mansur
authors.affiliation: Universidade Federal do Rio de Janeiro, Instituto de Química, 21941-909 Rio de Janeiro, RJ, Brazil.
authors.forename: Thiago A
authors.initials: TA
authors.lastname: Franco
authors.affiliation: Universidade Federal do Rio de Janeiro, Instituto de Bioquímica Médica, Programa de Biologia Molecular e Biotecnologia, 21941-902 Rio de Janeiro, RJ, Brazil.
authors.forename: Isabela B
authors.initials: IB
authors.lastname: Ramos
authors.affiliation: Universidade Federal do Rio de Janeiro, Instituto de Bioquímica Médica, Programa de Biologia Molecular e Biotecnologia, 21941-902 Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, Rio de Janeiro, Brazil.
authors.forename: Hatisaburo
authors.initials: H
authors.lastname: Masuda
authors.affiliation: Universidade Federal do Rio de Janeiro, Instituto de Química, 21941-909 Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, Rio de Janeiro, Brazil.
authors.forename: Ana C A
authors.initials: AC
authors.lastname: Melo
authors.affiliation: Universidade Federal do Rio de Janeiro, Instituto de Química, 21941-909 Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, Rio de Janeiro, Brazil. Electronic address: monica@iq.ufrj.br.
authors.forename: Mônica F
authors.initials: MF
authors.lastname: Moreira
mesh_terms: D000818:Animals; D014355:Chagas Disease; D002687:Chitin Synthase / Q000235:genetics*; D004199:Disease Vectors; D005260:Female; D018978:Molting / Q000235:genetics* / Q000502:physiology; D009866:Oogenesis / Q000235:genetics* / Q000502:physiology; D010058:Oviposition / Q000235:genetics* / Q000502:physiology; D034622:RNA Interference; D012330:RNA, Double-Stranded; D012239:Rhodnius / Q000235:genetics* / Q000378:metabolism*
chemical_list: D012330:RNA, Double-Stranded; D002687:Chitin Synthase
keywords: Chitin synthase; Cuticle; Ecdysis; Integument; Oogenesis; RNAi; Rhodnius prolixus