ARS | Publication request: Optimization of RNA interference (RNAi) targeting acetylcholinesterase in the Southern cattle tick (Rhipicephalus microplus)

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: November 15, 2011
Publication Date: N/A

Technical Abstract: Acetylcholinesterase (AChE) is the primary target for organophosphate (OP) acaricides. OP resistant strains of the Southern cattle tick Rhipicephalus microplus have been identified and represent a major threat to the control of this important disease vector. R. microplus ticks possess at least three AChE genes with different enzyme kinetics as well as additional noncatalytic functions. Alterations in the expression of the AChE genes in the synganglia of OP resistant strains have been reported and represent one mechanism for OP resistance. In order to elucidate the molecular basis for altered expression of the AChE genes in OP resistant strains, a dual luciferase reporter construct is being utilized to investigate the transcriptional and/or posttranscriptional regulation of these genes. In addition, the reporter facilitates quantitative analysis of the efficacy of RNA interference (RNAi) molecules designed to target different regions of the AChE genes. Upon establishing the most potent RNAi molecules, gene silencing experiments will be performed in vivo in R. microplus ticks. Preliminary evidence from our laboratory suggests that microinjection of dsRNA constructs targeting the three AChE genes simultaneously results in greater mortality of R. microplus ticks than targeting the AChE genes invidivually. Understanding the complex regulation of the AChE family of genes represents an important step in abating OP resistance and maintaining control of R. microplus. USDA is an equal opportunity provider and employer