Identification of mucins and their expression in the vector mosquito Aedes albopictus

Mucins, the main structural components of vertebrate respiratory, digestive and reproductive tract mucus, as well as insect peritrophic matrix, play important roles in protecting host cells from invading microbes and difficult external environments. Mucins are characterized by highly glycosylated proteins constituting the mucin domain that is rich in repetitive sequences of threonine, serine, and proline (PTS). Despite potential important roles, mosquito mucins remain largely uncharacterized. Here, we performed bioinformatics analyses to identify proteins with PTS repeat domain and predicted 43 mucins or mucin-related proteins in Aedes albopictus. Gene expression analysis revealed that these mucins are dynamically expressed across different development stages and in different organs of Aedes albopictus. Of note, blood feeding upregulated AALF016448 and AALF013291 expression in the midgut, fat body, and ovary, raising the possibility that these mucins play potential roles in reproduction, digestion, and intestinal defense against invading pathogens upon blood feeding. Our in silico identification, followed by expressional validation, thus established a valuable resource for further dissecting the functions of mucins for vector control.