Transmembrane proteins – Mining the cattle tick transcriptome

Abstract

Managing the spread and load of pathogen-transmitting ticks is an important task worldwide. The cattle tick, Rhipicephalus microplus, not only impacts the economy through losses in dairy and meat production, but also raises concerns for human health in regards to the potential of certain transmitted pathogens becoming zoonotic. However, novel strategies to control R. microplus are hindered by lack of understanding tick biology and the discovery of suitable vaccine or acaricide targets. The importance of transmembrane proteins as vaccine targets are well known, as is the case in tick vaccines with Bm86 as antigen. In this study, we describe the localization and functional annotation of 878 putative transmembrane proteins. Thirty proteins could be confirmed in the R. microplus gut using LC-MS/MS analysis and their roles in tick biology are discussed. To the best of our knowledge, 19 targets have not been reported before in any proteomics study in various tick species and the possibility of using the identified proteins as targets for tick control are discussed. Although tissue expression of identified putative proteins through expansive proteomics is necessary, this study demonstrates the possibility of using bioinformatics for the identification of targets for further evaluation in tick control strategies.

Prediction of G protein-coupled receptor encoding sequences from the synganglion transcriptome of the cattle tick, Rhipicephalus microplus

“…Transcripts of lesser abundance, such as GPCRs, would be less likely to appear in Sanger-based datasets. There is certainly overlap between the predicted identities of our overall synganglion transcriptome Contig dataset (Supplementary files 1 and 2) and the dataset from Richards et al (2015), however not with our dataset of predicted GPCRs. Bissinger et al (2011) reported the 454 pyrosequencing-derived synganglion transcriptome from the American dog tick, D. variabilis , and there was considerable over-lap in the identified transcripts from their dataset and ours.…”

“…A recent study by Richards et al (2015) used transcriptome data to predict transmembrane proteins from cattle tick nymphs, larvae, and adult female ovaries, salivary glands, and midguts. There was no overlap between their transmembrane protein dataset and our set of 112 candidate GPCR-encoding contigs.…”

RNA-seq analyses of the midgut from blood- and serum-fed Ixodes ricinus ticks

“…As tick feeding progresses, tick digest cells develop along the tick gut epithelium3, where nutrient endocytosis and lysosome maturation facilitate intracellular digestion4. Extensive characterisations of tick midguts have been conducted in various tick species, at both transcript56789 and protein69 levels, using massive parallel sequencing and mass spectrometry, respectively. All these studies have been carried out using pooled samples of midgut preparations dissected from a number of ticks fed naturally on laboratory animals.…”

Mining a differential sialotranscriptome of Rhipicephalus microplus guides antigen discovery to formulate a vaccine that reduces tick infestations

“…In spite of this early success, and perhaps due to the difficulties posed by natural tick-host associations, antigen selection for development of bovine anti-tick vaccines was subsequently diverted from testing salivary antigens towards a preference for “hidden” or “concealed” tick antigens, thus called because the host is not exposed to them during natural infestations and, consequently, the tick would not have developed an escape mechanism for these potential vaccine targets. All of the commercially available anti-tick vaccines were developed based on this principle, but they present variable efficacies and still require the application of acaricides for tick control [57]. Thus, development of an effective anti-tick vaccine is still in demand.…”