Investigation of Amblyomma cement proteins

Background: Amblyomma americanum (lone star tick) attaches to the host by inserting its hypostome, a structure of the mouthpart characterized by its harpoon like structure. After attachment, the tick salivates a plethora of pharmacologically active proteins to modulate the host immune defenses for attachment and prolonged blood-feeding. Additionally, the tick protects its mouth parts by building a solid proteinaceous matrix called the cement cone, which is thought to assist in long term tick attachment and modulate host defenses.

Methods/Findings:  This study analyzes the proteins of the tick cement by liquid chromatography-tandem mass spectroscopy (LC-MS/MS).  In addition to this total RNA isolated from female A. americanum throughout the blood meal is subjected to RNA sequencing to select glycine rich proteins (GRPs) which were differentially expressed in early time points of feeding. The selected proteins were analyzed using qualitative real time PCR and RNA interference. Recombinant protein was used to explore additional functions these proteins may have on host defenses.

Conclusion:  The data acquired by RNA-seq and qRT- PCR show differential expression of the selected GRPs at earlier time points in tick feeding.