Stereotypic generation of axial tenocytes from bipartite sclerotome domains in zebrafish

PLoS Genet. 2018 Nov 2;14(11):e1007775. doi: 10.1371/journal.pgen.1007775. eCollection 2018 Nov.

Abstract

Development of a functional musculoskeletal system requires coordinated generation of muscles, bones, and tendons. However, how axial tendon cells (tenocytes) are generated during embryo development is still poorly understood. Here, we show that axial tenocytes arise from the sclerotome in zebrafish. In contrast to mouse and chick, the zebrafish sclerotome consists of two separate domains: a ventral domain and a previously undescribed dorsal domain. While dispensable for sclerotome induction, Hedgehog (Hh) signaling is required for the migration and maintenance of sclerotome derived cells. Axial tenocytes are located along the myotendinous junction (MTJ), extending long cellular processes into the intersomitic space. Using time-lapse imaging, we show that both sclerotome domains contribute to tenocytes in a dynamic and stereotypic manner. Tenocytes along a given MTJ always arise from the sclerotome of the adjacent anterior somite. Inhibition of Hh signaling results in loss of tenocytes and enhanced sensitivity to muscle detachment. Together, our work shows that axial tenocytes in zebrafish originate from the sclerotome and are essential for maintaining muscle integrity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Genetically Modified
  • Body Patterning
  • Hedgehog Proteins / genetics
  • Hedgehog Proteins / metabolism
  • Muscles / embryology
  • Muscles / metabolism
  • Organogenesis
  • Signal Transduction
  • Somites / embryology
  • Tendons / embryology
  • Tendons / metabolism
  • Tenocytes / cytology*
  • Tenocytes / metabolism
  • Zebrafish / embryology*
  • Zebrafish / genetics
  • Zebrafish / metabolism
  • Zebrafish Proteins / genetics
  • Zebrafish Proteins / metabolism

Substances

  • Hedgehog Proteins
  • Zebrafish Proteins