Isolation of Ixodes ricinus salivary gland mRNA encoding factors induced during blood feeding.

Abstract

Abstract. In tick salivary glands, genes induced during blood feeding result in the expression of new proteins secreted into tick saliva. These proteins are potentially involved in modulation of vertebrate host immune and hemostatic responses. In this study, subtractive and full-length cDNA libraries were constructed by use of mRNA extracted from salivary glands of unfed and 5-day engorged Ixodes ricinus. Sequences from these 2 libraries were compared with European Molecular Biology Laboratory (EMBL)/GenBank databases, which led to their classification into 2 major groups. The first group comprises cDNAs that failed to match or showed low homology to genes of known function. The second group includes sequences that showed high homology to genes of known function-for example, anticoagulants, inhibitors of platelet aggregation, and immunomodulatory proteins. Analyses of corresponding proteins suggest that they may be secreted by salivary gland cells. To study the properties of the recombinant proteins, selected cDNAs were expressed in mammalian or bacterial systems.

Molecular and biological characterization of the Amblyomma americanum organic anion transporter polypeptide

“…Consistent with vertebrate Oatp/OATP genes that show multiple tissue expression patterns (St-Pierre et al, 2002;Gao et al, 2005;Choudhuri et al, 2003), our RT-PCR expression analyses data revealed that AamOatp mRNA is both constitutively and ubiquitously expressed, as it was it is expressed in all tested organs of ticks that fed for 1-7 days. Transcriptional regulation of tick genes has been shown in response to blood meal feeding, being either shut down or induced, up-or down regulated (Leboule et al, 2002a;Leboule et al, 2002b;Mulenga et al, 2001;Rudenko et al, 2005). In the case of AamOatp, the switch in expression pattern, from being predominant in the midgut during the first 5 days of feeding and the ovary, by day 7 of feeding suggest that AamOatp is transcriptionally regulated in response to changing physiological needs as tick feeding progresses.…”

Characterization of a Novel Salivary Immunosuppressive Protein from Ixodes ricinus Ticks

“…Recombinant Iris (rIris) protein was obtained as described by Leboulle et al (10). Briefly, iris cDNA was recovered by analyzing a representational difference analysis subtractive library.…”

“…The recombinant rIris/MBP protein was expressed in Escherichia coli by using the pMALC2-E vector (New England Biolabs, Hitchin, United Kingdom) containing MBP fusion partner. The rIris/ His protein was expressed in CHO-KI cells by using the pCDNA3.1/V5-His A vector containing the Epitag V5/His 6 tag fusion partner (10).…”

“…One clone, formerly named seq24 (GenBank accession no. AJ269658), was selected for further characterization of its recombinant protein (previously Seq24/MBP and Seq24/His), because of its similarity to the pig leukocyte elastase inhibitor (10). Elastase inhibitors have been identified in many mammalian species but also in arthropods like the leech Hirudo nipponia (11).…”

Exploring the messages of the salivary glands of Ixodes ricinus.

“…In a report in this issue, Leboulle and others 21 used a different approach to isolate salivary cDNAs from ticks. Their objective was the isolation of genes induced during the feeding process, genes whose products may be immunogenic molecules injected during feeding or molecules that may affect the host hemostatic or immune system.…”