Identification of candidate sialome components expressed in ixodid tick salivary glands using secretion signal complementation in mammalian cells

• Published in: Insect molecular biology Vol. 14; no. 4; pp. 403 - 414
• Main Authors: Lambson, B, Nene, V, Obura, M, Shah, T, Pandit, P, Ole-MoiYoi, O, Delroux, K, Welburn, S, Skilton, R, de Villiers, E
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.08.2005; Blackwell Publishing Ltd
• Subjects: Amblyomma variegatum; Amino Acid Motifs; Amino Acid Sequence; amino acid sequences; Animals; Base Sequence; cell lines; Cercopithecus aethiops; complementary DNA; Conserved Sequence; COS Cells; Female; gene expression; genetic complementation; Insect Proteins - genetics; Insect Proteins - physiology; Insect Proteins - secretion; ixodid tick; Ixodidae; Ixodidae - genetics; Ixodidae - physiology; Molecular Sequence Data; protein secretion; Protein Sorting Signals - genetics; Protein Sorting Signals - physiology; proteome; Random Amplified Polymorphic DNA Technique; Reverse Transcriptase Polymerase Chain Reaction; Rhipicephalus appendiculatus; RNA, Messenger - chemistry; RNA, Messenger - genetics; salivary gland; salivary glands; salivary proteins; Salivary Proteins and Peptides - genetics; Salivary Proteins and Peptides - physiology; Salivary Proteins and Peptides - secretion; secretion signal; Sequence Alignment; sequence homology; sialome; signal peptide; signal sequence trap; tick sialome; Transfection
• ISSN: 0962-1075; 1365-2583
• DOI: 10.1111/j.1365-2583.2005.00571.x

Ixodid ticks manipulate mammalian host pathways by secreting molecules from salivary glands. Novel cDNAs containing functional secretion signals were isolated from ixodid tick salivary glands using a signal sequence trap. Only 15/61 Rhipicephalus appendiculatus and 1/7 Amblyomma variegatum cDNAs had significant identity (< 1e-15) to previously identified sequences. Polypeptides that may interact with host pathways included a kinase inhibitor. Two proteins encoded homologues of the yolk protein vitellogenin and seventeen contained glycine-rich motifs. Four proteins without sequence matches had conserved structural folds, identified using a Threading algorithm. Predicted secretion signals were between fifteen and fifty-seven amino acids long. Four homologous polymorphic proteins contained conserved (26/27 residues) signal peptides. Ten functional tick secretion signals could not be unambiguously identified using predictive algorithms.