Chapter 11. The Morphogenesis and Biomineralization of the Sea Urchin Larval Skeleton

  1. Prof. Dr. Edmund Bäuerlein
  1. Fred H. Wilt and
  2. Charles A. Ettensohn

Published Online: 20 MAR 2008

DOI: 10.1002/9783527619443.ch11

Handbook of Biomineralization: Biological Aspects and Structure Formation

Handbook of Biomineralization: Biological Aspects and Structure Formation

How to Cite

Wilt, F. H. and Ettensohn, C. A. (2007) The Morphogenesis and Biomineralization of the Sea Urchin Larval Skeleton, in Handbook of Biomineralization: Biological Aspects and Structure Formation (ed E. Bäuerlein), Wiley-VCH Verlag GmbH, Weinheim, Germany. doi: 10.1002/9783527619443.ch11

Editor Information

  1. Max-Planck-Institute for Biochemistry, Department of Membrane Biochemistry, Am Klopferspitz 18 A, 82152 Planegg, Germany

Publication History

  1. Published Online: 20 MAR 2008
  2. Published Print: 25 MAY 2007

ISBN Information

Print ISBN: 9783527316410

Online ISBN: 9783527619443

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Keywords:

  • sea urchin;
  • spicules;
  • endoskeleton;
  • primary mesenchyme cells;
  • biomineralization

Summary

Sea urchin embryos construct an elaborate, calcareous endoskeleton. During gastrulation, a group of mesenchyme cells (primary mesenchyme cells, PMCs) fuse, and within pseudopodial cables connecting the cell bodies, the skeleton is secreted. This skeleton is composed almost totally (>99%) of CaCO3 by mass, and contains small amounts of protein. The resultant composite is harder and stronger than calcite, and much more resistant to fracture. In this chapter, the early embryonic specification and morphogenesis of the PMCs is discussed, as is the mode of formation of the skeletal elements by these cells. Recent information is also presented regarding a gene regulatory network that operates in the PMC lineage. New findings from the Stronglyocentrotus purpuratus genome project are discussed that have advanced our understanding of the genes that mediate biomineralization in this organism.