A BTB domain‐containing gene is upregulated by immune challenge

Abstract

20-Hydroxyecdysone (20E) is an important hormone that regulates the development of insects. Although previous evidence revealed that 20E promotes innate immunity in insects, the mechanism involved is still unclear. In this study, the HaBBP gene from Helicoverpa armigera is cloned, which contains BTB (broad-complex, tramtrack, and bric-a-brac), a BACK (BTB and carboxyl-terminus kelch repeats), and PHR (PAM, highwire, and RPM) domains. RT-PCR analysis of HaBBP and western blot analysis of HaBBP show that the mRNA and protein level are higher in the fat body and hemocytes during the molting and metamorphic stages compared with the feeding stage. HaBBP was upregulated by 20E in hemocytes. Knockdown of the 20E receptor EcR-B1 and the heterodimeric partner ultraspiracle protein USP1 in an epidermal cell line (HaEpi) blocked the transcription of HaBBP. HaBBP is distributed in granulocytes and plasmatocytes. Immune stimulation by Escherichia coli caused the upregulation of HaBBP in both hemocytes and fat body. Thus, HaBBP is regulated by the 20E signaling pathway, and is likely involved in the insect innate immunity.

20‐hydroxyecdysone transcriptionally regulates humoral immunity in the fat body ofHelicoverpa armigera

“…The immune system is an important target for pest control; thus, many immune‐related genes including PRRs and AMPs have been reported (Chai et al ., ; Tian et al ., ; Wang et al ., , , ; Yang et al ., ). Several genes, such as β‐thymosin (Zhang et al ., ), a BTB domain‐containing protein (Wang et al ., ) and CTLs (Wang et al ., ) have been shown to be responsive to 20E injections and immune challenges; however, little is known about how the innate immune response is developmentally regulated by ecdysone in H. armigera .…”

TATA-binding Protein (TBP) Involved in the Ecdysone Signal Pathway of Drosophila

“…During the holometabolous insects molting and metamorphosis, the integument is casted off, the larvae lose the old integument while the new one not becomes mature, then the insects dangerously exposed to attack by microorganisms. During this period, ecdysone upregulate some innate immunity genes protect insects is necessary [9,10]. While during infection, the TBP expression also increased [7], so we can speculate that ecdysone may upregulate innate immunity gene through the TBP.…”

Drosophila Hsp90 Gene Can be Upregulated by Ecdysone

“…During this stage, the insect body exposed to microorganisms, become dangerously and vulnerable. Some immunity genes will be unregulated by ecdysone to protect the insect [9,10]. The Insect hsp90 gene can also responses to temperature stress and all kind of infection [1].…”