Insight into the sialome of the castor bean tick, Ixodes ricinus.
BACKGROUND
In recent years, there have been several sialome projects revealing transcripts expressed in the salivary glands of ticks, which are important vectors of several human diseases. Here, we focused on the sialome of the European vector of Lyme disease, Ixodes ricinus.


RESULTS
In the attempt to describe expressed genes and their dynamics throughout the feeding period, we constructed cDNA libraries from four different feeding stages of Ixodes ricinus females: unfed, 24 hours after attachment, four (partially fed) and seven days (fully engorged) after attachment. Approximately 600 randomly selected clones from each cDNA library were sequenced and analyzed. From a total 2304 sequenced clones, 1881 sequences forming 1274 clusters underwent subsequent functional analysis using customized bioinformatics software. Clusters were sorted according to their predicted function and quantitative comparison among the four libraries was made. We found several groups of over-expressed genes associated with feeding that posses a secretion signal and may be involved in tick attachment, feeding or evading the host immune system. Many transcripts clustered into families of related genes with stage-specific expression. Comparison to Ixodes scapularis and I. pacificus transcripts was made.


CONCLUSIONS
In addition to a large number of homologues of the known transcripts, we obtained several novel predicted protein sequences. Our work contributes to the growing list of proteins associated with tick feeding and sheds more light on the dynamics of the gene expression during tick feeding. Additionally, our results corroborate previous evidence of gene duplication in the evolution of ticks.
Chmelar
Jindrich
J
Faculty of Science, University of South Bohemia, Ceské Budejovice, Czech Republic. chmelar@paru.cas.cz
Anderson
Jennifer M
JM
Mu
Jianbing
J
Jochim
Ryan C
RC
Valenzuela
Jesus G
JG
Kopecký
Jan
J
D000595:Amino Acid Sequence; D000818:Animals; D001096:Arachnid Vectors / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D019295:Computational Biology; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D020224:Expressed Sequence Tags; D020869:Gene Expression Profiling; D015723:Gene Library; D018884:Ixodes / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D010802:Phylogeny; D012463:Saliva / Q000378:metabolism; D012471:Salivary Proteins and Peptides / Q000737:chemistry / Q000235:genetics*; D017386:Sequence Homology, Amino Acid
D017931:DNA Primers; D018076:DNA, Complementary; D012471:Salivary Proteins and Peptides