title: Expression of sax1/nkx1.2 and sax2/nkx1.1 in zebrafish.
abstract: sax1/nkx1.2 and sax2/nkx1.1 are members of the evolutionally conserved NK-1 homeobox gene family. sax1/nkx1.2 is reported to be expressed in the central nervous system during early and late neurogenesis in the chick and mouse, but the expression of sax2/nkx1.1 has not been reported. We isolated zebrafish cDNAs for sax1/nkx1.2 and sax2/nkx1.1 and examined their expression. In zebrafish, unlike chick and mouse, sax1/nkx1.2 was expressed in the prospective medial floor plate from the mid-gastrula period and was dependent on Nodal signaling. From the early segmentation period, sax1/nkx1.2 was also expressed in the posterior neuroectoderm. sax2/nkx1.1 was expressed in the prospective extraocular muscles, mesencephalic neurons residing along the tract of the posterior commissure, ventral neurons in the hindbrain, and interneurons in the spinal cord.
authors.affiliation: Laboratory for Vertebrate Axis Formation, Center for Developmental Biology, RIKEN, 2-2-3 Minatojima-minami, Chuo-ku, Kobe, Hyogo 650-0047, Japan.
authors.forename: Young-Ki
authors.initials: YK
authors.lastname: Bae
authors.forename: Takashi
authors.initials: T
authors.lastname: Shimizu
authors.forename: Osamu
authors.initials: O
authors.lastname: Muraoka
authors.forename: Taijiro
authors.initials: T
authors.lastname: Yabe
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Hirata
authors.forename: Hideaki
authors.initials: H
authors.lastname: Nojima
authors.forename: Toshio
authors.initials: T
authors.lastname: Hirano
authors.forename: Masahiko
authors.initials: M
authors.lastname: Hibi
mesh_terms: D000818:Animals; D002490:Central Nervous System / Q000196:embryology*; D018507:Gene Expression Regulation, Developmental / Q000235:genetics / Q000502:physiology*; D018398:Homeodomain Proteins / Q000096:biosynthesis* / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D055457:Nodal Protein; D015398:Signal Transduction / Q000502:physiology; D014157:Transcription Factors / Q000096:biosynthesis* / Q000235:genetics; D016212:Transforming Growth Factor beta / Q000378:metabolism; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics; D029961:Zebrafish Proteins / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D018398:Homeodomain Proteins; C526007:NODAL protein, human; D055457:Nodal Protein; C526008:Nodal protein, mouse; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; D029961:Zebrafish Proteins; C495723:nkx1.2la protein, zebrafish; C495724:nkx1.2lb protein, zebrafish