RNAi mediated depletion of NSF in Amblyomma maculatum infected with Rickettsia parkeri

Rickettsia parkeri, one of the causes of Spotted Fever Group Rickettsiosis, is carried by the Gulf Coast Tick (GCT), Amblyomma maculatum.  Pathogen transmission is thought to occur through a transcytotic mechanism in which the pathogen utilizes the protein machinery involved in vesicle docking. Tick salivary gland exocytosis processes appear to be essential to tick feeding success and may be important for pathogen trafficking. Our work to date has demonstrated the role of highly conserved vesicle and plasma membrane-bound protein receptors (SNAREs) in regulating protein secretions in tick salivary gland cells.  NSF participates in the disassembly of the SNARE complex.  Gene expression of NSF follows a cyclic regulation pattern with up and down regulation of the transcript during each of the three feeding phase. RNA interference demonstrates that NSF plays an important role in prolonged tick feeding, since engorged tick weight was lower than in control ticks.  In this study, we used a combination of qRT-PCR, RNAi-mediated gene silencing and immunofluorescence to investigate the functional role of NSF in R. parkeri infected A. maculatum.