Expression of the fructose receptor BmGr9 and its involvement in the promotion of feeding, suggested by its co-expression with neuropeptide F1 in Bombyx mori.
Insect gustatory receptors (Grs) are members of a large family of proteins with seven transmembrane domains that provide insects with the ability to detect chemical signals critical for feeding, mating, and oviposition. To date, 69 Bombyx mori Grs (BmGrs) genes have been identified via genome studies. BmGr9 has been shown to respond specifically to fructose and to function as a ligand-gated ion channel selectively activated by fructose. However, the sites where this Gr are expressed remain unclear. We demonstrated using reverse transcription (RT)-PCR that BmGr9 is widely expressed in the central nervous system (CNS), as well as oral sensory organs. Additionally, immunohistochemistry was performed using anti-BmGr9 antiserum to show that BmGr9 is expressed in cells of the oral sensory organs, including the maxillary galea, maxillary palps, labrum, and labium, as well as in putative neurosecretory cells of the CNS. Furthermore, double immunohistochemical analysis showed that most BmGr9-expressing cells co-localized with putative neuropeptide F1-expressing cells in the brain, suggesting that BmGr9 is involved in the promotion of feeding behaviors. In addition, a portion of BmGr9-expressing cells in the brain co-localized with cells expressing BmGr6, a molecule of the sugar receptor clade, suggesting that sugars other than fructose are involved in the regulation of feeding behaviors in B. mori larvae.
Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei 2-24-16, Tokyo 184-8588, Japan.
Dingze
D
Mang
Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei 2-24-16, Tokyo 184-8588, Japan.
Min
M
Shu
Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei 2-24-16, Tokyo 184-8588, Japan.
Shiho
S
Tanaka
Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan.
Shinji
S
Nagata
Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei 2-24-16, Tokyo 184-8588, Japan.
Tomoyuki
T
Takada
Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei 2-24-16, Tokyo 184-8588, Japan.
Haruka
H
Endo
Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei 2-24-16, Tokyo 184-8588, Japan.
Shingo
S
Kikuta
Department of Biological Production, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Saiwai-cho 3-5-8, Fuchu, Tokyo 183-8509, Japan.
Hiroko
H
Tabunoki
Department of Biological Production, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Saiwai-cho 3-5-8, Fuchu, Tokyo 183-8509, Japan.
Kikuo
K
Iwabuchi
Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei 2-24-16, Tokyo 184-8588, Japan. Electronic address: ryoichi@cc.tuat.ac.jp.
Ryoichi
R
Sato
D000818:Animals; D012831:Bombyx / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D005247:Feeding Behavior; D005632:Fructose / Q000378:metabolism*; D015870:Gene Expression; D007150:Immunohistochemistry; D019476:Insect Proteins / Q000235:genetics* / Q000378:metabolism; D007814:Larva / Q000235:genetics / Q000502:physiology; D009479:Neuropeptides / Q000235:genetics* / Q000378:metabolism; D009928:Organ Specificity; D012313:RNA / Q000235:genetics / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA
D018076:DNA, Complementary; D019476:Insect Proteins; D009479:Neuropeptides; D011956:Receptors, Cell Surface; D005632:Fructose; D012313:RNA
Bombyx mori; Central nervous system; Co-localization; Gustatory receptor; Neurosecretory cells; Oral sensory organs