Knockdown of Aminopeptidase-N from Helicoverpa armigera Larvae and in Transfected Sf21 Cells by RNA Interference Reveals Its Functional Interaction with Bacillus thuringiensis Insecticidal Protein Cry1Ac

Diversity of aminopeptidases, derived from four lepidopteran gene duplications, and polycalins expressed in the midgut of Helicoverpa armigera: Identification of proteins binding the δ-endotoxin, Cry1Ac of Bacillus thuringiensis

“…Previously two APN genes, HaAPN1 and HaAPN3 (HaAPN3 here corresponds with HaAPN2 of Rajagopal et al, 2003) from H. armigera had been expressed in Trichoplusia cells and shown to bind Cry1Ac by ligand blot (Rajagopal et al, 2003). Cells expressing HaAPN1 showed aberrant morphology when exposed to Cry1Ac that was less severe when the expression of HaAPN1 had been reduced by RNAi (Sivakumar et al, 2007). A previous study employing the purification technique employed here had identified only one of the proteins, HaAPN1, by its N-terminal sequence (Liao et al, 2005).…”

“…Both were membrane-associated, catalytically active, and glycosylated (Rajagopal et al, 2003). Furthermore, reducing the expression of one of those APNs reduced the cytotoxicity of Cry1Ac toward the cells demonstrating the potential for resistance to develop by down-regulation or modification of an APN (Sivakumar et al, 2007). However, no instance of Bt resistance has been linked with a loss of binding to an APN.…”

Diet-delivered RNAi in Helicoverpa armigera – Progresses and challenges

“…RNAi mediated by dsRNA ingestion requires higher dosage and multiple administrations until the onset of silencing in insects when compared to RNAi via injection in the haemolymph (Chen et al, 2008;Tian et al, 2009;Zhu et al, 2011), although dosages needed to elicit effect via injection in H. armigera remain measured in micrograms (Bober and Rafaeli, 2010;Cai et al, 2014;Du et al, 2012;Hou et al, 2012;Qiao et al, 2014;Sivakumar et al, 2007;Tang et al, 2012;Wang et al, 2010;Yang and Han, 2014a).…”

Interaction of Bacillus thuringiensis Vegetative Insecticidal Protein with Ribosomal S2 Protein Triggers Larvicidal Activity in Spodoptera frugiperda

“…In this sequence of events, the interaction with the receptor is the most significant event since subsequent to interaction, pore formation is initialized, and that leads to lysis of epithelial cells. The identification and characterization of receptors from various insect larvae has led to the identification of following molecules as receptor to ICPs, such as cadherinlike protein (21), glycosyl phosphatidylinositol (GPI)-anchored aminopeptidase N (APN) (1,9,11,17,19,20), a GPI-anchored alkaline phosphatase (10,14), and a 270-kDa glycoconjugate (see references 2, 7, 9, and 16 and references therein for an extensive list of receptors). In addition, certain glycopeptides have been identified as lysis-initiating receptor molecules.…”