Identification of a cis-regulatory element required for 20-hydroxyecdysone enhancement of antimicrobial peptide gene expression in Drosophila melanogaster.
The antimicrobial peptide diptericin plays an important role in defence against microorganisms. Drosophila melanogaster diptericin mRNA levels showed an increase during the late final instar larval stage when the ecdysteroid titres increase to initiate metamorphosis. Deletion analysis in Drosophila melanogaster mbn2 (mbn2) cells identified a cis-regulatory element (AAGAAAGATCCCCTG) necessary for 20-hydroxyecdysone enhancement of peptidoglycan-induced expression of diptericin in the 3 kb diptericin promoter. Proteins extracted from mbn2 cells treated with peptidoglycan plus 20-hydroxyecdysone specifically bound to this element. 20-hydroxyecdysone also enhanced peptidoglycan-induced expression of four other antimicrobial peptide (AMP) genes--drosomycin, attacin-A, metchnikowin and cecropin A1. Moreover, in silico promoter analysis using the meme program showed that an eight-nucleotide region of the identified cis-regulatory element is present in the promoters of these four AMP genes. These studies suggest that 20-hydroxyecdysone regulates the expression of AMP genes through a conserved cis-regulatory element.
Zhang
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Department of Entomology, College of Agriculture, University of Kentucky, Lexington, KY, USA.
Palli
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SR
D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D002460:Cell Line; D016384:Consensus Sequence; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster / Q000166:cytology / Q000187:drug effects* / Q000235:genetics* / Q000254:growth & development; D004441:Ecdysterone / Q000494:pharmacology*; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects*; D017344:Genes, Insect; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000302:isolation & purification / Q000378:metabolism; D010457:Peptidoglycan / Q000494:pharmacology; D011485:Protein Binding / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020218:Response Elements / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction
D023181:Antimicrobial Cationic Peptides; C054756:DptA protein, Drosophila; D029721:Drosophila Proteins; D009687:Nuclear Proteins; D010457:Peptidoglycan; D012333:RNA, Messenger; C091227:DRS protein, Drosophila; D004441:Ecdysterone