title: Molecular characterization and expression of laccase genes in the salivary glands of the green rice leafhopper, Nephotettix cincticeps (Hemiptera: Cicadellidae).
abstract: The green rice leafhopper, Nephotettix cincticeps has a laccase (EC 1.10.3.2) in its salivary glands and saliva, possibly playing an important role in detoxifying plant phenolics and in salivary sheath coagulation during feeding. We aimed to clarify the function of saliva-specific laccase in a vascular-feeding insect, N. cincticeps, for which we cloned 2 cDNAs (NcLac1S and NcLac1G) from the salivary glands and 1 cDNA (NcLac2) from the epidermis. The NcLac1S, NcLac1G, and NcLac2 transcripts encoded 701-, 792-, and 729-amino-acid proteins, respectively. The putative proteins encoded by NcLac1S and NcLac2 were predicted to be soluble, whereas that encoded by NcLac1G was hydrophobic and predicted to have a C-terminal transmembrane domain. Real-time reverse transcriptase polymerase chain reaction analysis revealed that NcLac1S was expressed exclusively, and at a much higher level than NcLac1G and NcLac2 in the salivary glands. NcLac1G was also expressed in the epidermis, midgut, and Malpighian tubules. NcLac2 expression was highest in the epidermis. In situ hybridization revealed NcLac1S expression in the V-cells of the salivary glands, having proven laccase activity. Expression of NcLac1G and NcLac2 were not detected clearly in all cells in the salivary glands. Therefore, NcLac1S is responsible for the laccase activity detected in the salivary glands and saliva of this insect. This is the first report on gene cloning of salivary laccase from a vascular-feeding insect.
authors.affiliation: National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, Japan. hatto@affrc.go.jp
authors.forename: Makoto
authors.initials: M
authors.lastname: Hattori
authors.forename: Kazuko
authors.initials: K
authors.lastname: Tsuchihara
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Noda
authors.forename: Hirosato
authors.initials: H
authors.lastname: Konishi
authors.forename: Yasumori
authors.initials: Y
authors.lastname: Tamura
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Shinoda
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Nakamura
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Hasegawa
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D005260:Female; D015870:Gene Expression; D006430:Hemiptera / Q000201:enzymology* / Q000235:genetics; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism*; D042845:Laccase / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D012469:Salivary Glands / Q000201:enzymology*; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
chemical_list: D019476:Insect Proteins; D042845:Laccase