title: Tbx16 regulates hox gene activation in mesodermal progenitor cells.
abstract: The transcription factor T-box 16 (Tbx16, or Spadetail) is an essential regulator of paraxial mesoderm development in zebrafish (Danio rerio). Mesodermal progenitor cells (MPCs) fail to differentiate into trunk somites in tbx16 mutants and instead accumulate within the tailbud in an immature state. However, the mechanisms by which Tbx16 controls mesoderm patterning have remained enigmatic. We describe here the use of photoactivatable morpholino oligonucleotides to determine the Tbx16 transcriptome in MPCs. We identified 124 Tbx16-regulated genes that were expressed in zebrafish gastrulae, including several developmental signaling proteins and regulators of gastrulation, myogenesis and somitogenesis. Unexpectedly, we observed that a loss of Tbx16 function precociously activated posterior hox genes in MPCs, and overexpression of a single posterior hox gene was sufficient to disrupt MPC migration. Our studies support a model in which Tbx16 regulates the timing of collinear hox gene activation to coordinate the anterior-posterior fates and positions of paraxial MPCs.
authors.affiliation: Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Alexander Y
authors.initials: AY
authors.lastname: Payumo
authors.affiliation: Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Lindsey E
authors.initials: LE
authors.lastname: McQuade
authors.affiliation: Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Whitney J
authors.initials: WJ
authors.lastname: Walker
authors.affiliation: Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Sayumi
authors.initials: S
authors.lastname: Yamazoe
authors.affiliation: Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, California, USA.|Department of Developmental Biology, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: James K
authors.identifier: 0000-0002-9220-8436
authors.initials: JK
authors.lastname: Chen
mesh_terms: D000818:Animals; D005801:Genes, Homeobox / Q000235:genetics*; D008648:Mesoderm / Q000166:cytology / Q000378:metabolism*; D015394:Molecular Structure; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism*; D020825:T-Box Domain Proteins / Q000235:genetics / Q000378:metabolism*; D015027:Zebrafish; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D020825:T-Box Domain Proteins; D029961:Zebrafish Proteins; C112539:tbx16 protein, zebrafish