title: Identification and functional analysis of pointed homologs in Bombyx mori.
abstract: Using gene-knockdown techniques, we searched for endogenous Ets family proteins involved in the regulation of Escherichia coli-dependent lebocin promoter activation in the E. coli-responsive silkworm cell line NIAS-Bm-aff3. Results showed that the gene knockdown of BmPointeds (BmPNTs), Drosophila Pointed orthologs, enhanced E. coli-dependent lebocin promoter activation, suggesting that endogenous BmPNTs repress the activation of this promoter. Furthermore, we found that i) the BmPNT gene produced at least two alternative splicing isoforms, BmPNT1 and BmPNT2, both of which function as repressors; ii) BmPNTs were not associated with an already-reported repressor element, most proximal GGAA/T motif (EtsRE3), in lebocin promoter, which plays a role in the repression of E. coli- and BmRelish1-dependent lebocin promoter activation; iii) although BmPNTs did not directly affect BmRelish1-dependent lebocin promoter activation, they were able to directly repress its activation on the promoter lacking EtsRE3, probably because of competitive inhibition of binding of BmRelish1 to κB sites by BmPNTs; and iv) BmPNTs were mainly expressed in larval hemocytes, and the gene expression levels of BmPNT2, but not of BmPNT1, were decreased in response to E. coli and Bacillus subtilis. These findings suggest that endogenous BmPNTs are directly and indirectly involved in the repression of E. coli-mediated lebocin promoter activation in NIAS-Bm-aff3 cells.
authors.affiliation: Insect-Microbe Research Unit, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, Tsukuba 305-8634, Japan. Electronic address: htanaka1@affrc.go.jp.
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Tanaka
authors.affiliation: Insect-Microbe Research Unit, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, Tsukuba 305-8634, Japan.
authors.forename: Aki
authors.initials: A
authors.lastname: Sagisaka
mesh_terms: D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000235:genetics / Q000276:immunology; D001412:Bacillus subtilis / Q000502:physiology; D001483:Base Sequence; D012831:Bombyx / Q000235:genetics* / Q000276:immunology / Q000382:microbiology; D002460:Cell Line; D017124:Conserved Sequence; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000276:immunology; D029721:Drosophila Proteins / Q000235:genetics* / Q000276:immunology; D004926:Escherichia coli / Q000502:physiology; D015870:Gene Expression; D006434:Hemocytes / Q000276:immunology / Q000382:microbiology; D019476:Insect Proteins / Q000235:genetics* / Q000276:immunology; D007814:Larva / Q000235:genetics* / Q000276:immunology / Q000382:microbiology; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000276:immunology; D011401:Promoter Regions, Genetic; D020033:Protein Isoforms / Q000235:genetics / Q000276:immunology; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000276:immunology; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000235:genetics* / Q000276:immunology
chemical_list: D023181:Antimicrobial Cationic Peptides; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D019476:Insect Proteins; D009419:Nerve Tissue Proteins; D020033:Protein Isoforms; D011518:Proto-Oncogene Proteins; D014157:Transcription Factors; C095582:lebocin protein, Bombyx mori; C083884:pnt protein, Drosophila
keywords: Antimicrobial peptides; Ets family proteins; Gene expression; Insect immunity; Silkworm