The unique biomineralization transcriptome and proteome of Lytechinus variegatus teeth

Keith Alvares, Caroline J. DeHart, Paul M. Thomas, Neil L. Kelleher, Arthur Veis*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Background: Matrix-regulated biomineralization involves the specific nucleation and growth of mineral phases within or upon preformed structured organic matrices. We hypothesized that there might be a general mechanism whereby anionic, phosphorylated mineral ion-binding proteins assist in specifically locating the mineral ions with respect to the mineralizing structural organic matrix. Here we extended these studies to invertebrate mineralization in Lytechinus variegatus (Lv) teeth. Materials and Methods: The tooth proteins were extracted and the phosphoproteins occluded in the mineral were enriched by passage through a ProQ Diamond phosphoprotein enrichment column, and subjected to MS/MS analysis. A Lv RNA-seq derived transcriptome database was generated. The MS/MS data found 25 proteins previously classified as “Predicted uncharacterized proteins” and many of the spicule matrix proteins. As these 25 proteins were also identified with the transcriptome analysis, and were thus no longer “hypothetical” but real proteins in the Lv tooth. Each protein was analyzed for the presence of a signal peptide, an acidic pI≤4, and the ability to be phosphorylated. Results: Four new Lv tooth specific Pro-Ala-rich proteins were found, representing a new class of proteins. Conclusion: The tooth is different from the spicules and other urchin skeletal elements in that only the tooth contains both “high” and “very high” magnesium calcite, [Ca(1–X) Mg(X) CO3], where X is the mole fraction of Mg. We speculate that our newly discovered proline-alanine rich proteins, also containing sequences of acidic amino acids, may be involved in the formation of high magnesium and very high magnesium calcite.

Original languageEnglish (US)
Pages (from-to)20-29
Number of pages10
JournalConnective tissue research
StatePublished - Nov 8 2018


  • MS/MS
  • Mg Calcites
  • RNAseq
  • Sea Urchin teeth
  • biomineralization-related proteins

ASJC Scopus subject areas

  • Molecular Biology
  • Biochemistry
  • Rheumatology
  • Cell Biology
  • Orthopedics and Sports Medicine


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