title: A homeobox gene, pnx, is involved in the formation of posterior neurons in zebrafish.
abstract: A homeobox gene, pnx, is expressed in prospective posterior neurogenic regions and later in primary neurons. pnx expression was regulated by a signal from the non-axial mesendoderm and by Notch signaling. Pnx contains an Eh1 repressor domain, which interacted with Groucho and acted as a transcriptional repressor. Misexpression of pnx increased neural precursor cells and postmitotic neurons, which express neurogenin1 and elavl3/HuC, respectively. Expression of an antimorphic Pnx (VP16Pnx) or inhibition of Pnx by antisense morpholino oligonucleotide led to the reduction in the number of a subset of primary neurons. Misexpression of pnx promoted neurogenesis independent of Notch signaling. Epistatic analyses showed that Pnx also functions downstream of the Notch signal. These data indicate that pnx is a novel repressor-type homeobox gene that regulates posterior neurogenesis.
authors.affiliation: Laboratory for Vertebrate Axis Formation, Center for Developmental Biology, RIKEN, 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: Taijiro
authors.initials: T
authors.lastname: Yabe
authors.forename: Cheol-Hee
authors.initials: CH
authors.lastname: Kim
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Hirata
authors.forename: Hideaki
authors.initials: H
authors.lastname: Nojima
authors.forename: Osamu
authors.initials: O
authors.lastname: Muraoka
authors.forename: Toshio
authors.initials: T
authors.lastname: Hirano
authors.forename: Masahiko
authors.initials: M
authors.lastname: Hibi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D005801:Genes, Homeobox; D018398:Homeodomain Proteins / Q000235:genetics* / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000235:genetics; D009420:Nervous System / Q000196:embryology*; D009687:Nuclear Proteins; D010802:Phylogeny; D051880:Receptors, Notch; D015398:Signal Transduction / Q000502:physiology; D014157:Transcription Factors; D014158:Transcription, Genetic / Q000502:physiology; D015027:Zebrafish / Q000196:embryology*; D029961:Zebrafish Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D018398:Homeodomain Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; C109095:Nkx1-2 protein, mouse; D009687:Nuclear Proteins; D051880:Receptors, Notch; D014157:Transcription Factors; D029961:Zebrafish Proteins; C474349:pnx protein, zebrafish