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Bombyx mori E26 transformation‐specific 2 (BmEts2), an Ets family protein, represses Bombyx mori Rels (BmRels)‐mediated promoter activation of antimicrobial peptide genes in the silkworm Bombyx mori
Author(s) -
Tanaka H.,
Sagisaka A.,
Suzuki N.,
Yamakawa M.
Publication year - 2016
Publication title -
insect molecular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.955
H-Index - 93
eISSN - 1365-2583
pISSN - 0962-1075
DOI - 10.1111/imb.12244
Subject(s) - bombyx mori , biology , bombyx , transactivation , gene , repressor , promoter , gene knockdown , microbiology and biotechnology , transcription factor , genetics , gene expression
E26 transformation‐specific (Ets) family transcription factors are known to play roles in various biological phenomena, including immunity, in vertebrates. However, the mechanisms by which Ets proteins contribute to immunity in invertebrates remain poorly understood. In this study, we identified a cDNA encoding BmEts2, which is a putative orthologue of Drosophila Yan and human translocation‐ets‐leukemia/Ets‐variant gene 6, from the silkworm Bombyx mori . Expression of the BmEts2 gene was significantly increased in the fat bodies of silkworm larvae in response to injection with Escherichia coli and Staphylococcus aureus . BmEts2 overexpression dramatically repressed B. mori Rels (BmRels)‐mediated promoter activation of antimicrobial peptide genes in silkworm cells. Conversely, gene knockdown of BmEts2 significantly enhanced BmRels activity. In addition, two κB sites located on the 5 ′ upstream region of cecropin B1 were found to be involved in the repression of BmRels‐mediated promoter activation. Protein‐competition analysis further demonstrated that BmEts2 competitively inhibited binding of BmRels to κB sites. Overall, BmEts2 acts as a repressor of BmRels‐mediated transactivation of antimicrobial protein genes by inhibiting the binding of BmRels to κB sites.