Characterization of the Bombyx mori Cecropin A1 promoter regulated by IMD pathway

Abstract

Cecropin A1 (CecA1) promoter from Bombyx mori was cloned and characterized to provide insight into the transcriptional control of this antimicrobial peptide gene upon immune challenges. Reporter gene assays demonstrated that both Escherichia coli and lipopolysaccharide could induce expression in BmE cells but B. bombyseptieus or peptidoglycan failed, and the induction pattern of the reporter gene was coincident with the endogenous CecA1. Analysis of deletion and mutation constructs revealed that the regulatory region was the κB motif located between -176 and -166, and no other predicted elements on CecA1 promoter affected its inducibility. Insertion of additional κB motifs increased the activity of CecA1 promoter. Furthermore, binding of Relish to κB motif was confirmed by electrophoretic mobility shift assay. These findings indicate the regulatory mechanism of CecA1 expression in IMD pathway and suggest an approach of engineering antimicrobial peptide promoter with enhanced activities that may lead to broad applications.

Sublethal dose of phoxim and Bombyx mori nucleopolyhedrovirus interact to elevate silkworm mortality

“…Defensin, a cationic AMP, has been shown to exhibit antibacterial activity against gram‐positive bacteria . CecA, belonging to the cecropin family, is a soluble polypeptide with a wide antibacterial spectrum and strong antibacterial activity . In our study, we found a significantly increased level of defensin1 and a non‐significant increase in CecA after 24 h treatment with phoxim.…”

Stimulator of interferon genes (STING) provides insect antiviral immunity by promoting Dredd caspase–mediated NF-κB activation

“…A8592-2MG, Sigma), or GAPDH antibody (catalogue no. abs830030, Shanghai, China) following the standard procedure and then developed using SuperSignal TM West Pico PLUS Chemiluminescent Substrate (Thermo Fisher Scientific) as described previously (45).…”

A Fas associated factor negatively regulates anti-bacterial immunity by promoting Relish degradation in Bombyx mori

“…Expression vector of N-terminal Flag tagged full-length BmFAF (FAF-FL) or truncated forms and HA taggedBmDredd (HA-Dredd) was constructed following the same procedures of construction of Myc tagged-BmRelish (Myc-Relish) expression vector (Hua et al, 2015). Interfering dsRNA against BmFAF (dsFAF) or EGFP (dsEGFP) was generated using T7 in vitro Transcription Kit (Promega, USA) following the manufacturer's instruction.…”

“…In the present study, by employing an inducible promoter we characterized previously (Hua et al, 2015) and various biochemical assays, we investigated whether BmFAF is involved in modulation of Relish activity. We found BmFAF suppresses Relish activity by promoting its proteasomal degradation through direct interaction.…”