An ECM-bound, PDGF-like growth factor and a TGF-α-like growth factor are required for gastrulation and spiculogenesis in the Lytechinus embryo

Venkatesh Govindarajan, Ravi K. Ramachandran, Jenny M. George, Diane C. Shakes, Craig R. Tomlinson

Research output: Contribution to journalArticle

29 Scopus citations


Growth factors and the extracellular matrix have been shown to fulfill vital developmental roles in many embryonic systems. Our hypothesis is that a developmental role played by the extracellular matrix in sea urchins maybe the binding of a PDGF-like growth factor to promote signaling activity. We report here that anti-human PDGF-B antibodies and anti-human TGF-α antibodies immunoprecipitated specific proteins isolated from Lytechinus embryos. Addition of these antibodies to Lytechinus embryos inhibited gastrulation and spiculogenesis. The embryos are sensitive to the antibodies from the four-cell through the hatching blastula stages, which suggests that the TGF-α-like and PDGF-like ligands are required for the early differentiation of the gut and spicules. We present evidence that the PDGF-like growth factor depends on the extracellular matrix for signaling activity. Synthetic peptides representing the heparan sulfate proteoglycan binding sequence on human PDGF-B were added to Lytechinus embryo cultures to compete for binding sites with the endogenous PDGF-like growth factor. The experimental peptide inhibited gastrulation and caused radially arranged multiple spicules to form. Development was unaffected by a control peptide. These studies support our hypothesis and suggest that TGF-α-like and PDGF-like growth factors induce signaling events required for sea urchin gastrulation and spiculogenesis and suggest that an extracellular matrix-associated PDGF-like growth factor is involved in differentiation along the oral-aboral axis.

Original languageEnglish
Pages (from-to)541-551
Number of pages11
JournalDevelopmental Biology
Issue number2
Publication statusPublished - 1995
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Cell Biology
  • Developmental Biology
  • Molecular Biology

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