Specification of the zebrafish nervous system by nonaxial signals.
The organizer of the amphibian gastrula provides the neurectoderm with both neuralizing and posteriorizing (transforming) signals. In zebrafish, transplantations show that a spatially distinct transformer signal emanates from tissues other than the organizer. Cells of the germring (nonaxial mesendoderm) posteriorized forebrain progenitors when grafted nearby, resulting in an ectopic hindbrain-like structure; in contrast, cells of the organizer (axial mesendoderm) caused no posterior transformation. Local application of basic fibroblast growth factor, a candidate transformer in Xenopus, caused malformation but not hindbrain transformation in the forebrain. Thus, the zebrafish gastrula may integrate spatially distinct signals from the organizer and the germring to pattern the neural axis.
Woo
K
K
Division of Biology and Biological Imaging Center, Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA. kwoo@itsa.ucsf.edu
Fraser
S E
SE
D000818:Animals; D019521:Body Patterning; D017690:Cell Transplantation; D004268:DNA-Binding Proteins / Q000096:biosynthesis; D051767:Early Growth Response Protein 2; D004475:Ectoderm / Q000166:cytology / Q000502:physiology / Q000637:transplantation; D004707:Endoderm / Q000166:cytology / Q000502:physiology / Q000637:transplantation; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D005775:Gastrula / Q000502:physiology*; D008636:Mesencephalon / Q000196:embryology*; D008648:Mesoderm / Q000166:cytology / Q000502:physiology / Q000637:transplantation; D009024:Morphogenesis; D011994:Recombinant Proteins / Q000494:pharmacology; D012249:Rhombencephalon / Q000196:embryology*; D013234:Stem Cells / Q000502:physiology; D014157:Transcription Factors / Q000096:biosynthesis; D015027:Zebrafish / Q000196:embryology*
D004268:DNA-Binding Proteins; D051767:Early Growth Response Protein 2; D011994:Recombinant Proteins; D014157:Transcription Factors; D016222:Fibroblast Growth Factor 2