A BTB DOMAIN-CONTAININGGENE IS UPREGULATEDBY IMMUNE CHALLENGE

摘要

20-Hydroxyecdysone (20E) is an important hormone that regulates thedevelopment of insects. Although previous evidence revealed that 20Epromotes innate immunity in insects, the mechanism involved is stillunclear. In this study, the HaBBP gene from Helicoverpa armigera iscloned, 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 andwestern blot analysis of HaBBP show that the mRNA and protein levelare higher in the fat body and hemocytes during the molting andmetamorphic stages compared with the feeding stage. HaBBP wasupregulated by 20E in hemocytes. Knockdown of the 20E receptorEcR-B1 and the heterodimeric partner ultraspiracle protein USP1 in anepidermal cell line (HaEpi) blocked the transcription of HaBBP. HaBBPis distributed in granulocytes and plasmatocytes. Immune stimulation byEscherichia coli caused the upregulation of HaBBP in both hemocytesand fat body. Thus, HaBBP is regulated by the 20E signaling pathway,and is likely involved in the insect innate immunity.