title: Expression analysis of Egr-1 ortholog in metamorphic brain of honeybee (Apis mellifera L.): Possible evolutionary conservation of roles of Egr in eye development in vertebrates and insects.
abstract: Specific genes quickly transcribed after extracellular stimuli without de novo protein synthesis are known as immediate early genes (IEGs) and are thought to contribute to learning and memory processes in the mature nervous system of vertebrates. A recent study revealed that the homolog of Early growth response protein-1 (Egr-1), which is one of the best-characterized vertebrate IEGs, shared similar properties as a neural activity-dependent gene in the adult brain of insects. With regard to the roles of vertebrate Egr-1 in neural development, the contribution to the development and growth of visual systems has been reported. However, in insects, the expression dynamics of the Egr-1 homologous gene during neural development remains poorly understood. Our expression analysis demonstrated that AmEgr, a honeybee homolog of Egr-1, was transiently upregulated in the developing brain during the early to mid pupal stages. In situ hybridization and 5-bromo-2'-deoxyuridine (BrdU) immunohistochemistry revealed that AmEgr was mainly expressed in post-mitotic cells in optic lobes, the primary visual center of the insect brain. These findings suggest the evolutionarily conserved role of Egr homologs in the development of visual systems in vertebrates and insects.
authors.affiliation: Laboratory of Applied Entomology and Zoology, Graduate School of Agriculture, Tamagawa University, 6-1-1, Tamagawagakuen, Machida, Tokyo 194-8610, Japan. Electronic address: ugajin@agr.tamagawa.ac.jp.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Ugajin
authors.affiliation: Research Institute for Electronic Science, Hokkaido University, N20W10, Kita-Ward, Sapporo, Hokkaido 001-0020, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Watanabe
authors.affiliation: NODAI Genome Research Center, Tokyo University of Agriculture, 1-1-1, Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan.
authors.forename: Hironobu
authors.initials: H
authors.lastname: Uchiyama
authors.affiliation: Honeybee Science Research Center, Tamagawa University, 6-1-1, Tamagawagakuen, Machida, Tokyo 194-8610, Japan.
authors.forename: Tetsuhiko
authors.initials: T
authors.lastname: Sasaki
authors.affiliation: NODAI Genome Research Center, Tokyo University of Agriculture, 1-1-1, Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan; Department of Bioscience, Tokyo University of Agriculture, 1-1-1, Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Yajima
authors.affiliation: Laboratory of Applied Entomology and Zoology, Graduate School of Agriculture, Tamagawa University, 6-1-1, Tamagawagakuen, Machida, Tokyo 194-8610, Japan.
authors.forename: Masato
authors.initials: M
authors.lastname: Ono
mesh_terms: D000818:Animals; D001516:Bees / Q000235:genetics / Q000254:growth & development*; D005075:Biological Evolution; D001921:Brain / Q000166:cytology / Q000378:metabolism; D049109:Cell Proliferation; D017124:Conserved Sequence; D051766:Early Growth Response Protein 1 / Q000235:genetics / Q000378:metabolism*; D005091:Exons / Q000235:genetics; D005123:Eye / Q000254:growth & development* / Q000378:metabolism; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D017403:In Situ Hybridization; D008675:Metamorphosis, Biological / Q000235:genetics*; D009899:Optic Lobe, Nonmammalian / Q000166:cytology / Q000378:metabolism; D011679:Pupa / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014714:Vertebrates / Q000235:genetics*
chemical_list: D051766:Early Growth Response Protein 1
keywords: Egr; Honeybee; Immediate early gene; Metamorphosis; Optic lobe