Artículos de revistas
Molecular cloning and characterization of a glycine-like receptor gene from the cattle tick Rhipicephalus (Boophilus) microplus (Acari: Ixodidae)
Autor
MOISES MARTINEZ VELAZQUEZ
Institución
Resumen
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.