title: Novel middle-type Kenyon cells in the honeybee brain revealed by area-preferential gene expression analysis.
abstract: The mushroom bodies (a higher center) of the honeybee (Apis mellifera L) brain were considered to comprise three types of intrinsic neurons, including large- and small-type Kenyon cells that have distinct gene expression profiles. Although previous neural activity mapping using the immediate early gene kakusei suggested that small-type Kenyon cells are mainly active in forager brains, the precise Kenyon cell types that are active in the forager brain remain to be elucidated. We searched for novel gene(s) that are expressed in an area-preferential manner in the honeybee brain. By identifying and analyzing expression of a gene that we termed mKast (middle-type Kenyon cell-preferential arrestin-related protein), we discovered novel 'middle-type Kenyon cells' that are sandwiched between large- and small-type Kenyon cells and have a gene expression profile almost complementary to those of large- and small-type Kenyon cells. Expression analysis of kakusei revealed that both small-type Kenyon cells and some middle-type Kenyon cells are active in the forager brains, suggesting their possible involvement in information processing during the foraging flight. mKast expression began after the differentiation of small- and large-type Kenyon cells during metamorphosis, suggesting that middle-type Kenyon cells differentiate by modifying some characteristics of large- and/or small-type Kenyon cells. Interestingly, CaMKII and mKast, marker genes for large- and middle-type Kenyon cells, respectively, were preferentially expressed in a distinct set of optic lobe (a visual center) neurons. Our findings suggested that it is not simply the Kenyon cell-preferential gene expression profiles, rather, a 'clustering' of neurons with similar gene expression profiles as particular Kenyon cell types that characterize the honeybee mushroom body structure.
authors.affiliation: Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
authors.forename: Kumi
authors.initials: K
authors.lastname: Kaneko
authors.forename: Tsubomi
authors.initials: T
authors.lastname: Ikeda
authors.forename: Mirai
authors.initials: M
authors.lastname: Nagai
authors.forename: Sayaka
authors.initials: S
authors.lastname: Hori
authors.forename: Chie
authors.initials: C
authors.lastname: Umatani
authors.forename: Hiroto
authors.initials: H
authors.lastname: Tadano
authors.forename: Atsushi
authors.initials: A
authors.lastname: Ugajin
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Nakaoka
authors.forename: Rajib Kumar
authors.initials: RK
authors.lastname: Paul
authors.forename: Tomoko
authors.initials: T
authors.lastname: Fujiyuki
authors.forename: Kenichi
authors.initials: K
authors.lastname: Shirai
authors.forename: Takekazu
authors.initials: T
authors.lastname: Kunieda
authors.forename: Hideaki
authors.initials: H
authors.lastname: Takeuchi
authors.forename: Takeo
authors.initials: T
authors.lastname: Kubo
mesh_terms: D000818:Animals; D019393:Arrestin / Q000145:classification / Q000235:genetics; D001516:Bees / Q000235:genetics*; D001921:Brain / Q000166:cytology / Q000378:metabolism*; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000235:genetics; D017404:In Situ Hybridization, Fluorescence; D019476:Insect Proteins / Q000235:genetics; D008856:Microscopy, Fluorescence; D024521:Mushroom Bodies / Q000166:cytology / Q000378:metabolism*; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D010802:Phylogeny; D020133:Reverse Transcriptase Polymerase Chain Reaction; D059467:Transcriptome
chemical_list: D019393:Arrestin; D019476:Insect Proteins; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2