title: Molecular cloning and characterization of a glycine-like receptor gene from the cattle tick Rhipicephalus (Boophilus) microplus (Acari: Ixodidae).
abstract: The cattle tick Rhipicephalus (Boophilus) microplus is the most economically important ectoparasite affecting the cattle industry in tropical and subtropical areas around the world. The principal method of tick control has relied mainly on the use of chemical acaricides, including ivermectin; however, cattle tick populations resistant to ivermectin have recently been reported in Brazil, Mexico, and Uruguay. Currently, the molecular basis for ivermectin susceptibility and resistance are not well understood in R. microplus. This prompted us to search for potential molecular targets for ivermectin. Here, we report the cloning and molecular characterization of a R. microplus glycine-like receptor (RmGlyR) gene. The characterized mRNA encodes for a 464-amino acid polypeptide, which contains features common to ligand-gated ion channels, such as a large N-terminal extracellular domain, four transmembrane domains, a large intracellular loop and a short C-terminal extracellular domain. The deduced amino acid sequence showed around 30% identity to GlyRs from some invertebrate and vertebrate organisms. The polypeptide also contains the PAR motif, which is important for forming anion channels, and a conserved glycine residue at the third transmembrane domain, which is essential for high ivermectin sensitivity. PCR analyses showed that RmGlyR is expressed at egg, larval and adult developmental stages. Our findings suggest that the deduced receptor is an additional molecular target to ivermectin and it might be involved in ivermectin resistance in R. microplus.
authors.affiliation: Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco, AC, Av. Normalistas 800, Col. Colinas de la Normal, 44270 Guadalajara, Jalisco, México.
authors.forename: José Miguel
authors.initials: JM
authors.lastname: Flores-Fernández
authors.affiliation: Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco, AC, Av. Normalistas 800, Col. Colinas de la Normal, 44270 Guadalajara, Jalisco, México.
authors.forename: Abel
authors.initials: A
authors.lastname: Gutiérrez-Ortega
authors.affiliation: Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco, AC, Av. Normalistas 800, Col. Colinas de la Normal, 44270 Guadalajara, Jalisco, México.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Padilla-Camberos
authors.affiliation: Centro Nacional de Investigaciones en Parasitología Veterinaria-INIFAP, Carretera Federal Cuernavaca Cuautla No. 8534, Colonia Progreso, 62550 Jiutepec, Morelos, México.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Rosario-Cruz
authors.affiliation: Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco, AC, Av. Normalistas 800, Col. Colinas de la Normal, 44270 Guadalajara, Jalisco, México.
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Hernández-Gutiérrez
authors.affiliation: Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco, AC, Av. Normalistas 800, Col. Colinas de la Normal, 44270 Guadalajara, Jalisco, México.
authors.forename: Moisés
authors.initials: M
authors.lastname: Martínez-Velázquez
mesh_terms: D056810:Acaricides / Q000494:pharmacology; D000595:Amino Acid Sequence; D000818:Animals; D060829:Arthropod Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D004351:Drug Resistance / Q000235:genetics; D004926:Escherichia coli; D018507:Gene Expression Regulation, Developmental; D007473:Ion Channels / Q000235:genetics / Q000378:metabolism; D007559:Ivermectin / Q000494:pharmacology; D007814:Larva; D008969:Molecular Sequence Data; D010063:Ovum; D012333:RNA, Messenger / Q000235:genetics; D018009:Receptors, Glycine / Q000235:genetics* / Q000378:metabolism; D048494:Rhipicephalus / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D056810:Acaricides; D060829:Arthropod Proteins; D018076:DNA, Complementary; D007473:Ion Channels; D012333:RNA, Messenger; D018009:Receptors, Glycine; D007559:Ivermectin