논문 상세보기
Cloning of an Insulin-like Peptide and its Control of Plasma Trehalose Level in Spodoptera exigua
Like vertebrate insulins, insulin-like peptides (ILPs) play crucial roles in controlling immature growth, adult lifespan, and plasma sugar level in some insects. An ILP gene (SeILP1) was predicted from a transcription database of Spodoptera exigua. SeILP1 encodes 95 amino acid sequence, which shares sequence homologies (33~83%) with other insects ILPs. The predicted B and A chains possess six cysteine residences. SeILP1 was expressed in all developmental stages of S. exigua. However, its expression was detected in fat body, gut and epidermis, but not in hemocytes. Its expression increased with feeding activity. Plasma trehalose levels of fifth instar larvae maintained at relatively stable concentration of 2.31±0.62 mM. However, starvation induced a significant increase of plasma trehalose level by more than two fold in 48 h, at which SeILP1 expression kept at a low level. RNA interference of SeILP1 induced a significant increase of plasma trehalose level. Interestingly, a bovine insulin decreased plasma trehalose level in a dose-dependent manner. These results indicate mat SeILP1 plays a role in suppressing plasma trehalose level in S. exigua.
