title: 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.
abstract: 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.
authors.affiliation: Insect-Microbe Research Unit, National Institute of Agrobiological Sciences, Ibaraki, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Tanaka
authors.affiliation: Insect-Microbe Research Unit, National Institute of Agrobiological Sciences, Ibaraki, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Sagisaka
authors.affiliation: Division of Insect Sciences, National Institute of Agrobiological Sciences, Ibaraki, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Suzuki
authors.affiliation: Division of Insect Sciences, National Institute of Agrobiological Sciences, Ibaraki, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Yamakawa
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000235:genetics / Q000378:metabolism; D012831:Bombyx / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D007814:Larva / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D023181:Antimicrobial Cationic Peptides; D018076:DNA, Complementary; D019476:Insect Proteins; D012333:RNA, Messenger; D014157:Transcription Factors
keywords: Bombyx mori; Ets family protein; antimicrobial peptides; gene regulation; silkworm