Molecular identification, characterization, and expression analysis of a serine protease inhibitor gene from cotton bollworm, Helicoverpa armigera (Lepidoptera: Noctuidae)

Abstract

Serine protease inhibitors (serpins), a superfamily of protease inhibitors, are known to be involved in several physiological processes, such as development, metamorphosis, and innate immunity. In our study, a full-length serpin cDNA, designated Haserpin1, was isolated from the cotton bollworm Helicoverpa armigera. The cDNA sequence of Haserpin1 is 1176 nt long, with an open reading frame encoding 391 amino acids; there is one exon and no intron. The predicted molecular weight of Haserpin1 is 43.53 kDa, with an isoelectric point of 4.98. InterProScan was employed for Haserpin1 functional characterization, which revealed that Haserpin1 contains highly conserved signature motifs, including a reactive center loop (RCL) with a hinge region (E341–N350), the serpin signature, (F367–F375) and a predicted P1–P1′ cleavage site (L357–S358), which are useful for identifying serpins. Transcripts of Haserpin1 were constitutively expressed in the fat body, suggesting that it is the major site for serpin synthesis. During the developmental stages, a fluctuation in the expression level of Haserpin1 was observed, with low expression detected at the 5th-instar larval stage. In contrast, relatively high expression was detected at the prepupal stage, suggesting that Haserpin1 might play a critical role at the H. armigera wandering stage. Although the detailed function of this serpin (Haserpin1) needs to be elucidated, our study provides a perspective for the functional investigation of serine protease inhibitor genes.

Comparative Proteomic Analysis of Rhipicephalus sanguineus sensu lato (Acari: Ixodidae) Tropical and Temperate Lineages: Uncovering Differences During Ehrlichia canis Infection

“…TIL-type protease inhibitors have been reported to inhibit proteases such as trypsin, cathepsin, elastase, and chymotrypsin, thus playing an important role in ticks physiological processes, improving parasitism mechanisms, and facilitating blood feeding by interfering with defense-related host peptidases (Shakeel and Zafar, 2020). Although information about this class of proteins, in insects and ticks, is limited, members of the TIL domain containing protein have been identified in blood-feeding insects and tick sialomes (Mans, 2011;Tirloni et al, 2014;Maruyama et al, 2017).…”