title: Male tarsi specific odorant-binding proteins in the diving beetle Cybister japonicus sharp.
abstract: Odorant binding proteins (OBPs) play critical roles in chemical communication of insects, as they recognize and transport environmental chemical signals to receptors. The diving beetle Cybister japonicus Sharp shows a remarkable sexual dimorphism. The foreleg tarsi of males are equipped with large suction cups, believed to help holding the female during underwater courtship and mating. Here, we identified two OBPs highly and specifically expressed in male tarsi, suggesting important functions of these structures in chemical communication. The first protein, CjapOBP1, exhibits the 6 conserved cysteines motif of classic OBPs, while the second, CjapOBP2, contains only four cysteines and can be assigned to the sub-class of C-minus OBPs. Both proteins were expressed in a bacterial system and the purified recombinant proteins were used to for antibodies preparation. Western Blot analysis showed that CjapOBP1 is predominantly expressed in male tarsi and could be also detected in antennae and palpi of both sexes, while CjapOBP2, besides male tarsi, is also present in testis. Ligand-binding experiments showed a good binding affinity between CjapOBP1, CjapOBP2 and citral and coniferyl aldehyde, respectively. These results support a possible function of these two OBPs in the male foreleg tarsi of diving beetles in chemical communication.
authors.affiliation: College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China.
authors.forename: Li-Mei
authors.initials: LM
authors.lastname: Song
authors.affiliation: HuangPu Entry-Exit Inspection and Quarantine Bureau, Guangdong, 510730, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Jiang
authors.affiliation: Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 10 0193, China.
authors.forename: Xue-Min
authors.initials: XM
authors.lastname: Wang
authors.affiliation: College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China.
authors.forename: Jin-Dong
authors.initials: JD
authors.lastname: Li
authors.affiliation: Department of Entomology, Washington State University, Pullman, WA, 99164, USA.
authors.forename: Fang
authors.initials: F
authors.lastname: Zhu
authors.affiliation: Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
authors.forename: Xiong-Bing
authors.initials: XB
authors.lastname: Tu
authors.affiliation: Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
authors.forename: Ze-Hua
authors.initials: ZH
authors.lastname: Zhang
authors.affiliation: College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China.
authors.forename: Li-Ping
authors.initials: LP
authors.lastname: Ban
mesh_terms: D020816:Amino Acid Motifs; D000818:Animals; D057506:Arthropod Antennae / Q000378:metabolism; D003001:Cloning, Molecular / Q000379:methods*; D001517:Coleoptera / Q000378:metabolism / Q000502:physiology*; D005260:Female; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008297:Male; D008958:Models, Molecular; D009928:Organ Specificity; D010802:Phylogeny; D018035:Receptors, Odorant / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D012727:Sex Characteristics; D012726:Sexual Behavior, Animal; D013737:Testis / Q000378:metabolism
chemical_list: D019476:Insect Proteins; D018035:Receptors, Odorant; C045648:odorant-binding protein