An insight into the sialome of the adult female mosquito Aedes albopictus

To gain insight into the molecular repertoire of the adult female salivary glands of the tiger mosquito Aedes albopictus, we performed transcriptome and proteome analysis. cDNA clones were sequenced and assembled in clusters of related sequences and the corresponding genes assigned to one of three categories: housekeeping (H; 31%), secreted (S; 34%), or unknown (U; 35%) function. Among the putative secreted factors are proteins known to be widely distributed in the saliva of blood-sucking Diptera, such as D7 and antigen 5 family members, as well as proteins that are mosquito- or culicine-specific, i.e., the 30-kDa allergen or the 62-kDa and 34-kDa families, respectively. Expression of 15 of these salivary proteins was confirmed by Edman degradation. Tissue and sex specificity of selected transcripts were evaluated by RT-PCR and identified at least 32 genes whose expression is restricted or enriched in the female salivary glands of Ae. albopictus, whereas 17 additional genes were expressed in female glands and adult males but not in other tissues of adult females. For approximately one third of the genes analyzed, involvement in blood-feeding, sugar digestion, immune response, or other more generic physiological roles can be postulated; however, no functions can be suggested for the remaining sequences, which therefore likely represent either novel functions or novel molecules recruited during the evolution of hematophagy. Supplemental spreadsheets with hyperlinks to all sequences used in this manuscript are hyperlinked throughout the text and can be found at http://www.ncbi.nlm.nih.gov/projects/omes/#salivarytranscriptomes.