BhSGAMP-1, a gene that encodes an antimicrobial peptide, is developmentally regulated by the direct action of 20-OH ecdysone in the salivary gland of Bradysia hygida (Diptera, Sciaridae).
Recently we have shown that BhSGAMP-1 is a developmentally regulated reiterated gene that encodes an antimicrobial peptide (AMP) and is expressed exclusively in the salivary glands, at the end of the larval stage. We show, for the first time, that a gene for an AMP is directly activated by 20-OH ecdysone. This control probably involves the participation of short-lived repressor(s). We also found that the promoter of BhSGAMP-1 is not equipped with elements that respond to infection, provoked by the injection of microorganisms, in the salivary glands or in the fat body. We produced polyclonal antibodies against the synthetic peptide and found that the BhSGAMP-1 peptide is secreted in the saliva. The BhSGAMP-1 gene was also activated during the third larval molt. These facts confirm our hypothesis that this preventive system of defense was selected to produce an environment free of harmful microorganisms in the insect's immediate vicinity, during molts.
Zanarotti
Gabriela Morilha
GM
Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, 14049-900 Ribeirão Preto, SP, Brazil.
Cândido-Silva
Juliana A
JA
de Almeida
Jorge Cury
JC
D000818:Animals; D015153:Blotting, Western; D004175:Diptera / Q000235:genetics* / Q000378:metabolism / Q000382:microbiology; D004441:Ecdysterone / Q000494:pharmacology* / Q000502:physiology; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000502:physiology; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects*; D054884:Host-Pathogen Interactions; D019476:Insect Proteins / Q000235:genetics* / Q000378:metabolism; D007814:Larva / Q000187:drug effects / Q000235:genetics / Q000382:microbiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012441:Saccharomyces cerevisiae / Q000502:physiology; D012469:Salivary Glands / Q000187:drug effects* / Q000378:metabolism; D012471:Salivary Proteins and Peptides / Q000235:genetics* / Q000378:metabolism; D013211:Staphylococcus aureus / Q000502:physiology
D019476:Insect Proteins; D012471:Salivary Proteins and Peptides; D004441:Ecdysterone