Biochemical Characterization Of Insect Intestinal Mucin SeIIM8 And Silencing Seiim8 By RNAi From Spodoptera Exigua

Spodoptera exigua, which mainly eats vegetables, cotton, and ornamental plants, is a kind of omnivorous pest. The PM lines the gut of most insects at one or more stages of the life cycle. PMs can protect the digestive tract from physical damages and microbial infections. The chitin of the PM appears to form a fibrous structure to which the protein and Insect Intestinal Mucin (IIM) adheres. The IIM is heavily decorated with a large number of O-linked oligo-saccharides. These oligo-saccharides maybe attach to the pathogens to prevent their combination to the epithelial cells. Since they all lie on the IIM, IIM has been the target to destroy the PM for pest control.To over-express SeIIM8 in insect cells, a recombinant baculovirus was constructed by using the Bac-to-Bac system from Invitrogen. Recombinant SeIIM8 was a secreted protein after infecting HighFive cell line, which was in logarithmic growth with the recombinant Bac-iim8. The mature SeIIM8 protein, which was 120kDa of predicted molecular weight, has a modular structure of six chitin-binding domains, a mucin-like domain and a Asp-Lys-rich domain.RNAi has been widely used as an effective technology to study gene function. The dsRNA specific to seiim8 was synthesized in vitro, and then injected into insect larvae. As a result, the expression of seiim8 may be suppressed...