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HMGB1‐like dorsal switch protein 1 of the mealworm, Tenebrio molitor , acts as a damage‐associated molecular pattern
Author(s) -
Mollah Md. Mahi Imam,
Kim Yonggyun
Publication year - 2021
Publication title -
archives of insect biochemistry and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.576
H-Index - 66
eISSN - 1520-6327
pISSN - 0739-4462
DOI - 10.1002/arch.21795
Subject(s) - biology , mealworm , rna interference , spodoptera , immune system , microbiology and biotechnology , prophenoloxidase , antimicrobial peptides , innate immune system , rna , gene , biochemistry , peptide , immunology , botany , larva , recombinant dna
High‐mobility group box 1 (HMGB1) is a nuclear protein highly conserved in eukaryotes and ubiquitously expressed to regulate transcription and chromatin remodeling. Dorsal switch protein 1 (DSP1) is its insect homolog. A lepidopteran DSP1 acts as a damage‐associated molecular pattern (DAMP) in response to immune challenge. The objective of this study was to determine the role of DAMP in the mealworm beetle, Tenebrio molitor , a coleopteran insect. DSP1 of T. molitor ( Tm‐DSP1 ) encodes 536 amino acids and shares sequence similarities with Homo sapiens HMGB1 (56.3%) and Spodoptera exigua DSP1 (59.2%). An antisera raised against S. exigua DSP1 was cross‐reactive to Tm‐DSP1 . Like other insect DSPs, Tm‐DSP1 has a relatively long N‐terminal extension in addition to two conserved HMG box domains. It was expressed in all developmental stages of T. molitor and different larval tissues. Upon immune challenge, its expression level was upregulated. Its RNA interference (RNAi) treatment resulted in a significant reduction in immune responses measured by hemocyte nodule formation against bacterial infection. In addition, the induction of some antimicrobial peptide genes to the immune challenge was suppressed by its RNAi treatment. Interestingly, phospholipase A 2 associated with eicosanoid biosynthesis was significantly suppressed in its catalytic activity by the RNAi treatment specific to Tm‐DSP1 expression. Without any pathogen infection, injection of a lepidopteran DSP1 induced both cellular and humoral immune responses. These results suggest that Tm‐DSP1 in T. molitor can act as a DAMP molecule and mediate immune responses upon immune challenge.