Characterization and transcriptional profiles of three Spodoptera frugiperda genes encoding cysteine-rich peptides. A new class of defensin-like genes from lepidopteran insects?
The present work describes sequence and transcription of three Spodoptera frugiperda genes encoding 6-cysteine-rich peptides. Sequence alignments indicate that the predicted peptides belong to the insect defensin family, although phylogenetic analyses suggest they form a cluster distinct from that of other neopteran insect defensins. The three genes were identified in a non-immune-challenged Sf9 cells cDNA (DNA complementary to RNA) library (Landais et al., Bioinformatics, in press) and were named spodoptericin, Sf-gallerimycin and Sf-cobatoxin. Spodoptericin is a novel defensin-like gene that appears to be weakly up-regulated following injection of bacteria and fungi. Interestingly, no sequence motif clearly homologous to cis regulatory element involved in the regulation of antimicrobial genes was found. An homologue of the spodoptericin gene was identified in the SilkBase Bombyx mori cDNA library. Sf-gallerimycin is related to the Galleria mellonella gallerimycin gene and is induced after immune challenge by injection of bacteria in the larval fat body as well as in hemocytes. In silico analysis of the sequence upstream from the cDNA reveals the presence of at least one motif homologous to a nuclear factor kappaB (NF-kappaB) binding site. Finally, Sf-cobatoxin is related to the G. mellonella cobatoxin-like gene. Despite high levels of constitutive expression compared to the two previous genes, transcription of Sf-cobatoxin is increased after immune, in particular, bacterial challenge. We therefore confirm that these three genes encode potential candidate molecules involved in S. frugiperda innate humoral response.
Laboratoire de Pathologie Comparée, UMR 5087 INRA-CNRS/Universite Montpellier II, 30380 Saint-Christol-les-Alès, France. volkoff@ensam.inra.fr
Anne Nathalie
AN
Volkoff
Janick
J
Rocher
Emmanuelle
E
d'Alençon
Martine
M
Bouton
Igor
I
Landais
Enrique
E
Quesada-Moraga
Alain
A
Vey
Philippe
P
Fournier
Kazuei
K
Mita
Gérard
G
Devauchelle
D000595:Amino Acid Sequence; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000235:genetics; D001483:Base Sequence; D002460:Cell Line; D004247:DNA / Q000737:chemistry / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics / Q000302:isolation & purification; D023082:Defensins / Q000235:genetics; D005216:Fat Body / Q000166:cytology / Q000378:metabolism; D018628:Gene Dosage; D005786:Gene Expression Regulation; D017344:Genes, Insect / Q000235:genetics; D006434:Hemocytes / Q000378:metabolism; D019476:Insect Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D011401:Promoter Regions, Genetic / Q000235:genetics; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D018411:Spodoptera / Q000166:cytology / Q000235:genetics* / Q000382:microbiology; D014158:Transcription, Genetic; D015854:Up-Regulation
D023181:Antimicrobial Cationic Peptides; D018076:DNA, Complementary; D023082:Defensins; D019476:Insect Proteins; D004247:DNA