BMP signaling is required for nkx2.3-positive pharyngeal pouch progenitor specification in zebrafish

PLoS Genet. 2019 Feb 14;15(2):e1007996. doi: 10.1371/journal.pgen.1007996. eCollection 2019 Feb.

Abstract

Pharyngeal pouches, a series of outpocketings that bud from the foregut endoderm, are essential to the formation of craniofacial skeleton as well as several important structures like parathyroid and thymus. However, whether pharyngeal pouch progenitors exist in the developing gut tube remains unknown. Here, taking advantage of cell lineage tracing and transgenic ablation technologies, we identified a population of nkx2.3+ pouch progenitors in zebrafish embryos and demonstrated an essential requirement of ectodermal BMP2b for their specification. At early somite stages, nkx2.3+ cells located at lateral region of pharyngeal endoderm give rise to the pouch epithelium except a subpopulation expressing pdgfαa rather than nkx2.3. A small-scale screen of chemical inhibitors reveals that BMP signaling is necessary to specify these progenitors. Loss-of-function analyses show that BMP2b, expressed in the pharyngeal ectoderm, actives Smad effectors in endodermal cells to induce nkx2.3+ progenitors. Collectively, our study provides in vivo evidence for the existence of pouch progenitors and highlights the importance of BMP2b signaling in progenitor specification.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Genetically Modified
  • Body Patterning / genetics
  • Body Patterning / physiology
  • Bone Morphogenetic Protein 2 / genetics
  • Bone Morphogenetic Protein 2 / metabolism*
  • Cell Lineage / genetics
  • Cell Lineage / physiology
  • Embryonic Stem Cells / cytology
  • Embryonic Stem Cells / metabolism
  • Endoderm / embryology
  • Endoderm / metabolism
  • Homeodomain Proteins / genetics
  • Homeodomain Proteins / metabolism*
  • Mutation
  • Pharynx / embryology
  • Pharynx / metabolism
  • Platelet-Derived Growth Factor / genetics
  • Platelet-Derived Growth Factor / metabolism
  • Signal Transduction
  • Smad Proteins / metabolism
  • Somites / embryology
  • Somites / metabolism
  • Zebrafish / embryology*
  • Zebrafish / genetics
  • Zebrafish / metabolism*
  • Zebrafish Proteins / genetics
  • Zebrafish Proteins / metabolism*

Substances

  • Bone Morphogenetic Protein 2
  • Homeodomain Proteins
  • Nkx2.3 protein, zebrafish
  • Platelet-Derived Growth Factor
  • Smad Proteins
  • Zebrafish Proteins
  • bmp2b protein, zebrafish
  • platelet-derived growth factor A

Grants and funding

The research was funded by grants from the National Key Research and Development Program of China (2016YFA0100503, Q.W.), the National Natural Science Foundation of China ((31571501 and 91739101, Q.W.) and the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA16000000, Q.W.). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.