Identification and characterization of an Apolipophorin-III gene from Actias selene Hübner (Lepidoptera: Saturniidae)

Abstract

Apolipophorin-III (ApoLp-III) is involved in lipid transport and innate immunity in insects. In this study, we isolated ApoLp-III gene (As-ApoLp-III) cDNA from Actias selene Hübner (Lepidoptera: Saturniidae). It contained 660 nucleotides with a putative open reading frame (ORF) of 561bp encoding 186 amino acid residues. It showed similarities with ApoLp-III proteins from other insect species, especially Antheraea pernyi. The recombinant protein of As-ApoLp-III was expressed in Escherichia coli, and anti-As-ApoLp-III antibodies were prepared. The As-ApoLp-III gene was expressed at high levels in the fat body and integument, and at low levels in the hemolymph, testis, silk gland, malpighian tubule, ovary, and midgut. As-ApoLp-III gene can be upregulated by E. coli, Micrococcus luteus, Beauveria bassiana, and nuclear polyhedrosis virus (NPV) and showed a greater sensitivity for gram-negative bacteria and fungi than for gram-positive bacteria and virus. These data indicated that As-ApoLp-III may play an important role in innate immune responses of Actias selene.