RNA interference in the blacklegged tick, Ixodes scapularis: Disappointment and success

Ticks are obligatory ectoparasites that feed exclusively on the blood of vertebrates and often transmit a number of pathogens, including viruses, bacteria, and protozoa, resulting in substantial economic loss in the animal industry and presenting risks to human health.  The blacklegged tick, Ixodes scapularis, is known to transmit an important tick-borne pathogen, Borrelia burgdorferi, the causative agent of Lyme Disease.  Tick salivary glands, and their secretions, contain various bioactive components that aid in the manipulation of hosts' defenses.  The identification and functional study of such molecules and their relationships to pathogen transmission has become a critical step in understanding and preventing disease transmission in ticks.  Research in this area has boomed since the release of the I. scapularis genome, and the use of RNA interference has proven invaluable in these efforts for several tick species, allowing for the enhanced study of functional genomics in these non-model arthropod vectors.  Here, we discuss RNA interference as it applies to studies in the blacklegged tick, Ixodes scapularis. We consider a brief history of RNAi within this tick species, current efforts in our lab to implement this technique in the study of several I. scapularis genes, and address potential concerns moving forward.