Molecular and phylogenetic analysis of a novel family of fibrinogen-related proteins from mosquito Aedes albopictus cell line

Since lectins have been proposed to function as non-self recognizing molecules, it is important to access the specificity and diversity of lectin molecules that play an important role as pattern recognition receptors (PRRs). Like vertebrates, several lectins containing fibrinogen-like (FBG) domains have been reported as PRRs from different invertebrate species, however, in case of mosquito, very little information is available. In this study, we report identification and characterization of a novel family of fibrinogen-related proteins which exhibits (43–68%) similarities to that of A. gambiae FREPs, isolated from the immune challenged cell line of mosquito Aedes albopictus. Analysis of the longest (790 bp) cDNA (AF-1) appears to encode a 263 deduced amino acid sequence that contains a C-terminal fibrinogen-like domain. Amino acid sequence similarity and phylogenetic analysis showed a high degree of conservation with other known insect fibrinogen-related proteins, suggesting that mosquito A. albopictus FREPs may play a similar role in an innate immunity as pattern recognition receptor molecules; however, further characterization is needed to understand their transcriptional regulation and behavior during microbial infection.