Molecular identification and characterization of two new Lepidoptera chemoreceptors belonging to the Drosophila melanogaster OR83b family.
In insect antennae, olfaction depends on olfactory receptors (ORs) that function through heterodimerization with an unusually highly conserved partner orthologue to the Drosophila melanogaster DOR83b. Here, we report the identification of two cDNAs encoding new DOR83b orthologues that represent the first members, although nonconventional, of the OR families of two noctuid crop pests, the cotton leafworm Spodoptera littoralis and the cabbage armyworm Mamestra brassicae. They both displayed high protein sequence conservation with previously identified DOR83b orthologues. Transcripts were abundantly detected in adult chemosensory organs as well as in fifth instar larvae heads. In adult antennae, the expression patterns of both genes revealed common features with other members of the OR83b subfamily: they appeared to be expressed at the bases of numerous olfactory sensilla belonging to different functional categories, suggesting that both receptors may be co-expressed with yet unidentified conventional ORs. Bioinformatic analyses predicted the occurrence of seven transmembrane domains and an unusual topology with intracellular N-termini and extracellular C-termini, extending to Lepidoptera the hypothesis of an inverted topology for DOR83b orthologues, demonstrated to date only in D. melanogaster.
Malpel
S
S
INRA-UPMC-AgroParisTech UMR 1272 PISC Physiologie de l'Insecte: Signalisation et Communication, Versailles, France.
Merlin
C
C
François
M-C
MC
Jacquin-Joly
E
E
D000595:Amino Acid Sequence; D000825:Animal Structures / Q000378:metabolism; D000818:Animals; D029721:Drosophila Proteins / Q000737:chemistry / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000378:metabolism*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D007915:Lepidoptera / Q000235:genetics*; D008297:Male; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D018035:Receptors, Odorant / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D029721:Drosophila Proteins; C492465:Orco protein, Drosophila; D018035:Receptors, Odorant