title: Expression of neuropeptide- and hormone-encoding genes in the Ciona intestinalis larval brain.
abstract: Despite containing only approximately 330 cells, the central nervous system (CNS) of Ciona intestinalis larvae has an architecture that is similar to the vertebrate CNS. Although only vertebrates have a distinct hypothalamus-the source of numerous neurohormone peptides that play pivotal roles in the development, function, and maintenance of various neuronal and endocrine systems, it is suggested that the Ciona brain contains a region that corresponds to the vertebrate hypothalamus. To identify genes expressed in the brain, we isolated brain vesicles using transgenic embryos carrying Ci-β-tubulin(promoter)::Kaede, which resulted in robust Kaede expression in the larval CNS. The associated transcriptome was investigated using microarray analysis. We identified 565 genes that were preferentially expressed in the larval brain. Among these genes, 11 encoded neurohormone peptides including such hypothalamic peptides as gonadotropin-releasing hormone and oxytocin/vasopressin. Six of the identified peptide genes had not been previously described. We also found that genes encoding receptors for some of the peptides were expressed in the brain. Interestingly, whole-mount in situ hybridization showed that most of the peptide genes were expressed in the ventral brain. This catalog of the genes expressed in the larval brain should help elucidate the evolution, development, and functioning of the chordate brain.
authors.affiliation: Marine Genomics Unit, Okinawa Institute of Science and Technology Promotion Corporation, Onna, Okinawa 904-0412, Japan. hamadam@oist.jp
authors.forename: Mayuko
authors.initials: M
authors.lastname: Hamada
authors.forename: Naoki
authors.initials: N
authors.lastname: Shimozono
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Ohta
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Satou
authors.forename: Takeo
authors.initials: T
authors.lastname: Horie
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Kawada
authors.forename: Honoo
authors.initials: H
authors.lastname: Satake
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Sasakura
authors.forename: Nori
authors.initials: N
authors.lastname: Satoh
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D001921:Brain / Q000254:growth & development* / Q000378:metabolism*; D002938:Ciona intestinalis / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D019143:Evolution, Molecular; D018507:Gene Expression Regulation, Developmental; D007031:Hypothalamus / Q000254:growth & development / Q000378:metabolism; D017403:In Situ Hybridization; D007447:Invertebrate Hormones / Q000235:genetics; D007814:Larva / Q000254:growth & development / Q000378:metabolism; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D043562:Receptors, G-Protein-Coupled / Q000235:genetics; D018013:Receptors, Neuropeptide / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics; D014714:Vertebrates / Q000254:growth & development / Q000378:metabolism
chemical_list: D007447:Invertebrate Hormones; D009479:Neuropeptides; D043562:Receptors, G-Protein-Coupled; D018013:Receptors, Neuropeptide; D014157:Transcription Factors