ZFIN ID: ZDB-PUB-010205-2
Plasticity in zebrafish hox expression in the hindbrain and cranial neural crest
Schilling, T.F., Prince, V., and Ingham, P.W.
Date: 2001
Source: Developmental Biology   229: 201-216 (Journal)
Registered Authors: Ingham, Philip, Prince, Victoria E., Schilling, Tom
Keywords: zebrafish; Hox; neural crest; hindbrain; pharyngeal arch; rhombomere; segment
MeSH Terms:
  • Animals
  • Bone and Bones/embryology
  • Ectoderm/physiology
  • Gene Expression Regulation, Developmental*
  • Homeodomain Proteins/genetics*
  • Neural Crest/metabolism*
  • Rhombencephalon/metabolism*
  • Xenopus Proteins*
  • Zebrafish/embryology*
  • Zebrafish Proteins*
PubMed: 11180963 Full text @ Dev. Biol.
The anterior-posterior identities of cells in the hindbrain and cranial neural crest are thought to be determined by their Hox gene expression status, but how and when cells become committed to these identities remain unclear. Here we address this in zebrafish by cell transplantation, to test plasticity in hox expression in single cells. We transplanted cells alone, or in small groups, between hindbrain rhombomeres or between the neural crest primordia of pharyngeal arches. We found that transplanted cells regulated hox expression according to their new environments. The degree of plasticity, however, depended on both the timing and the size of the transplant. At later stages transplanted cells were more likely to be irreversibly committed and maintain their hox expression, demonstrating a progressive loss of responsiveness to the environmental signals that specify segmental identities. Individual transplanted cells also showed greater plasticity than those lying within the center of larger groups, suggesting that a community effect normally maintains hox expression within segments. We also raised experimental embryos to larval stages to analyze transplanted cells after differentiation and found that neural crest cells contributed to pharyngeal cartilages appropriate to the anterior-posterior level of the new cellular environment. Thus, consistent with models implicating hox expression in control of segmental identity, plasticity in hox expression correlates with plasticity in final cell fate.