title: Visualization of neural activity in insect brains using a conserved immediate early gene, Hr38.
abstract: Many insects exhibit stereotypic instinctive behavior [1-3], but the underlying neural mechanisms are not well understood due to difficulties in detecting brain activity in freely moving animals. Immediate early genes (IEGs), such as c-fos, whose expression is transiently and rapidly upregulated upon neural activity, are powerful tools for detecting behavior-related neural activity in vertebrates [4, 5]. In insects, however, this powerful approach has not been realized because no conserved IEGs have been identified. Here, we identified Hr38 as a novel IEG that is transiently expressed in the male silkmoth Bombyx mori by female odor stimulation. Using Hr38 expression as an indicator of neural activity, we mapped comprehensive activity patterns of the silkmoth brain in response to female sex pheromones. We found that Hr38 can also be used as a neural activity marker in the fly Drosophila melanogaster. Using Hr38, we constructed a neural activity map of the fly brain that partially overlaps with fruitless (fru)-expressing neurons in response to female stimulation. These findings indicate that Hr38 is a novel and conserved insect neural activity marker gene that will be useful for a wide variety of neuroethologic studies.
authors.affiliation: Division of Biological Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan.
authors.forename: Nozomi
authors.initials: N
authors.lastname: Fujita
authors.forename: Yuka
authors.initials: Y
authors.lastname: Nagata
authors.forename: Takumi
authors.initials: T
authors.lastname: Nishiuchi
authors.forename: Makoto
authors.initials: M
authors.lastname: Sato
authors.forename: Masafumi
authors.initials: M
authors.lastname: Iwami
authors.forename: Taketoshi
authors.initials: T
authors.lastname: Kiya
mesh_terms: D000818:Animals; D012831:Bombyx / Q000235:genetics / Q000502:physiology*; D001921:Brain / Q000502:physiology; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics / Q000502:physiology*; D005260:Female; D017781:Genes, Immediate-Early; D019476:Insect Proteins / Q000235:genetics* / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D009474:Neurons / Q000378:metabolism; D010675:Pheromones / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D012724:Sex Attractants / Q000378:metabolism
chemical_list: D029721:Drosophila Proteins; C095176:Hr38 protein, Drosophila; D019476:Insect Proteins; D010675:Pheromones; D018160:Receptors, Cytoplasmic and Nuclear; D012724:Sex Attractants; C010411:insect attractants