title: Two gap junction channel (innexin) genes of the Bombyx mori and their expression.
abstract: Gap junctions are clusters of intercellular channels that are associated with embryonic development and neural signaling. Innexins, invertebrate gap junction proteins, have been identified in Drosophila and Caenorhabditis. Here, we report the isolation and characterization of two novel members of the insect innexin family, Bm inx2 and Bm inx4, from embryos of the silkworm, Bombyx mori, during the germ-band formation stage. Bm inx2 is a single copy gene with one exon, while Bm inx4 is a single copy gene with four exons and three introns. The predicted proteins show structural similarities with other innexin family members, including four transmembrane (TM) domains, two extracellular loops (ELs), one cytoplasmic loop (CL), and typical conserved amino acids. Bm inx2 is phylogenetically orthologous to the other insect inx2 genes, but Bm inx4 is not orthologous to any known innexin including Dm inx4. Interestingly, Northern blotting and in situ hybridization showed that Bm inx2 was variously expressed across all developmental stages and in various tissues, with high expression seen in the nervous system at the time of embryogenesis. In contrast, Bm inx4 was transiently expressed at the germ-band formation stage of embryogenesis, and was specifically expressed in the ovary and testis during the larval and pupal stages. The isolation and characterization of these novel genes should form the basis for further study of the functional events that occur during development and neuronal communication in B. mori.
authors.affiliation: College of Agriculture and Life Sciences, Kyungpook National University, Daegu 702701, Republic of Korea.
authors.forename: Sun-Mee
authors.initials: SM
authors.lastname: Hong
authors.forename: Seok-Woo
authors.initials: SW
authors.lastname: Kang
authors.forename: Tae-Won
authors.initials: TW
authors.lastname: Goo
authors.forename: Nam-Soon
authors.initials: NS
authors.lastname: Kim
authors.forename: Jin-Sung
authors.initials: JS
authors.lastname: Lee
authors.forename: Kyung-A
authors.initials: KA
authors.lastname: Kim
authors.forename: Si-Kab
authors.initials: SK
authors.lastname: Nho
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D012831:Bombyx / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D016000:Cluster Analysis; D017630:Connexins / Q000235:genetics* / Q000378:metabolism*; D017931:DNA Primers / Q000235:genetics; D020224:Expressed Sequence Tags; D015870:Gene Expression; D017403:In Situ Hybridization; D008969:Molecular Sequence Data; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA
chemical_list: D017630:Connexins; D017931:DNA Primers