Reconstructing Connective Tissue Lineage Diversification at the Single Cell Level in the Zebrafish Face

Abstract

Assembly of the vertebrate face requires the precisely regulated differentiation of neural crest‐derived cells into a diversity of connective tissue fates, including cartilage, bone, and tendon/ligament cells. In order to better understand spatiotemporal regulation of this process, we are conducting a single‐cell transcriptomic analysis of neural crest‐derived cells from embryonic through adult stages. Our preliminary data reveal different trajectories for permanent cartilage, replacement cartilage, bone, and tendon/ligament cells, as well as diverse populations of undifferentiated cells in the adult face that may represent distinct progenitor populations. In the embryo, we have confirmed the presence of both multipotent and lineage‐committed cells through clonal labeling of sox10:CreER animals treated with a limiting dose of tamoxifen. We have also uncovered novel genes implicated in early lineage decisions. In particular, we find that the nuclear receptor transcription factor Nr5a2 marks cells destined to become lower jaw tendons, which we show by generating an nr5a2:GFP knock‐in transgenic reporter and performing time‐lapse microscopy. In nr5a2 mutants, tendon precursors marked by nr5a2:GFP inappropriately become cartilage cells, which results in an enlarged lower jaw cartilage that fails to properly attach to lower jaw musculature due to loss of tendons. These ongoing studies validate genomics approaches in identifying new regulators of connective tissue fates in the developing face.Support or Funding InformationNIDCR R35 DE027550This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.