An insight into the sialome of Anopheles funestus reveals an emerging pattern in anopheline salivary protein families

Abstract

Anopheles funestus, together with Anopheles gambiae, is responsible for most malaria transmission in sub-Saharan Africa, but little is known about molecular aspects of its biology. To investigate the salivary repertoire of this mosquito, we randomly sequenced 916 clones from a salivary-gland cDNA library from adult female F1 offspring of field-caught An. funestus. Thirty-three protein sequences, mostly full-length transcripts, are predicted to be secreted salivary proteins. We additionally describe 25 full-length housekeeping-associated transcripts. In accumulating mosquito sialotranscriptome information--which includes An. gambiae, Anopheles stephensi, Anopheles darlingi, Aedes aegypti, Aedes albopictus, Culex pipiens quinquefasciatus, and now An. funestus--a pattern is emerging. First, ubiquitous protein families are recruited for a salivary role, such as members of the antigen-5 family and enzymes of nucleotide and carbohydrate catabolism. Second, a group of protein families exclusive to blood-feeding Nematocera includes the abundantly expressed D7 proteins also found in sand flies and Culicoides. A third group of proteins, only found in Culicidae, includes the 30 kDa allergen family and several mucins. Finally, 10 protein and peptide families, five of them multigenic, are exclusive to anophelines. Among these proteins may reside good epidemiological markers to measure human exposure to anopheline species such as An. funestus and An. gambiae.

The Salivary Gland Transcriptome of the Eastern Tree Hole Mosquito,Ochlerotatus triseriatus

“…The remaining transcripts code for other H functions, as indicated in Table 1, and have <2 ESTs per contig. This distribution is typical of previous mosquito sialotranscriptomes (Valenzuela et al 2003;Ribeiro et al 2004Ribeiro et al ,2007Arca et al 2007;Calvo et al 2007a). …”

“…OT-547 codes for a peptide that is 57% identical to this Aedes protein, and weaker (<40%) identities to other proteins. Interestingly, OT-547 contains the block I-G-x(10)-G-x(2)-W-x(2)-G-x(5)-Ex(2)-R-R-x-F, which was deducted from alignment of anopheline proteins of the 6.2-kDa family described in previous sialotranscriptomes (Arca et al 2005, Calvo et al 2007a, 2009b. Alignment of OT-547 to the Aedes and anopheline sequences (Fig.…”

An insight into the sialotranscriptome of the non-blood feeding Toxorhynchites amboinensis mosquito

“…This was done exactly as before (Calvo et al, 2007a). EST were trimmed of primer and vector sequences, clusterized, and compared with other databases as previously described (Valenzuela et al, 2003).…”

“…Recent sialotranscriptome analysis of adult female mosquitoes has uncovered a putative cocktail of SG-secreted polypeptides numbering near 70 gene products Arca et al, 2005;Calvo et al, 2007a;Ribeiro et al, 2007). For most of these putative secreted polypeptides, no functional assignment is possible based on their primary sequence.…”

Genomic resources for invertebrate vectors of human pathogens, and the role of VectorBase

“…Identifying any of these compounds is potentially of interest to the medical industry. Ribeiro and collaborators have already characterized some of these agents through studies of mosquito salivary gland gene expression (Ribeiro et al, 2006;Calvo et al, 2007;Santos et al, 2007).…”