Chapter 8
Echinoderms as Blueprints for Biocalcification:
Regulation of Skeletogenic Genes and Matrices
Valeria Matranga, Rosa Bonaventura, Caterina Costa, Konstantinos
Karakostis, Annalisa Pinsino, Roberta Russo, and Francesca Zito
Contents
8.1 The Basis of Biomineral Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
8.2 Biomineral Contents and Shapes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228
8.3 Cells Involved in Adult Echinoderms Biomineralization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230
8.3.1 Biomineral Formation and Regenerative Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230
8.4 Cellular Signaling and Biomineral Formation in the Sea Urchin Embryo . . . . . . . . . . . . . . 231
8.4.1 Extracellular Matrix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234
8.4.2 Growth Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
8.5 Ecotoxicological Approaches to the Study of Skeletogenesis . . . . . . . . . . . . . . . . . . . . . . . . . . . 239
8.5.1 Metals Affecting Biomineralization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240
8.5.2 Ionizing Radiations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240
8.5.3 Impacts of Ocean Acidification on Biocalcification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241
8.6 Concluding Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
Abstract Echinoderms have an extensive endoskeleton composed of magnesian
calcite, a form of calcium carbonate that contains small amounts of magnesium
carbonate and occluded matrix proteins. Adult sea urchins have several calcified
structures, including test, teeth, and spines, composed of numerous ossicles which
form a three-dimensional meshwork of mineral trabeculae, the stereom. The
biomineral development begins in 24-hour-old embryos within the primary mesenchyme cells (PMCs), the only cells producing a set of necessary matrix proteins.
The deposition of the biomineral occurs in a privileged extracellular space
produced by the fused filopodial processes of the PMCs. We showed for the first
time that signals from ectoderm cells overlying PMCs play an important role in the
regulation of biomineralization-related genes. It is believed that growth factors
V. Matranga (*)
Consiglio Nazionale delle Ricerche, Istituto di Biomedicina e Immunologia Molecolare “Alberto
Monroy”, Via Ugo La Malfa 153, 90146 Palermo, Italy
e-mail: matranga@ibim.cnr.it
W.E.G. M€ uller (ed.), Molecular Biomineralization, Progress in Molecular
and Subcellular Biology 52, DOI 10.1007/978-3-642-21230-7_8,
# Springer-Verlag Berlin Heidelberg 2011
225
Echinoderms as Blueprints for Biocalcification:
Regulation of Skeletogenic Genes and Matrices
Valeria Matranga, Rosa Bonaventura, Caterina Costa, Konstantinos
Karakostis, Annalisa Pinsino, Roberta Russo, and Francesca Zito
Contents
8.1 The Basis of Biomineral Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
8.2 Biomineral Contents and Shapes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228
8.3 Cells Involved in Adult Echinoderms Biomineralization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230
8.3.1 Biomineral Formation and Regenerative Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230
8.4 Cellular Signaling and Biomineral Formation in the Sea Urchin Embryo . . . . . . . . . . . . . . 231
8.4.1 Extracellular Matrix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234
8.4.2 Growth Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
8.5 Ecotoxicological Approaches to the Study of Skeletogenesis . . . . . . . . . . . . . . . . . . . . . . . . . . . 239
8.5.1 Metals Affecting Biomineralization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240
8.5.2 Ionizing Radiations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240
8.5.3 Impacts of Ocean Acidification on Biocalcification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241
8.6 Concluding Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
Abstract Echinoderms have an extensive endoskeleton composed of magnesian
calcite, a form of calcium carbonate that contains small amounts of magnesium
carbonate and occluded matrix proteins. Adult sea urchins have several calcified
structures, including test, teeth, and spines, composed of numerous ossicles which
form a three-dimensional meshwork of mineral trabeculae, the stereom. The
biomineral development begins in 24-hour-old embryos within the primary mesenchyme cells (PMCs), the only cells producing a set of necessary matrix proteins.
The deposition of the biomineral occurs in a privileged extracellular space
produced by the fused filopodial processes of the PMCs. We showed for the first
time that signals from ectoderm cells overlying PMCs play an important role in the
regulation of biomineralization-related genes. It is believed that growth factors
V. Matranga (*)
Consiglio Nazionale delle Ricerche, Istituto di Biomedicina e Immunologia Molecolare “Alberto
Monroy”, Via Ugo La Malfa 153, 90146 Palermo, Italy
e-mail: matranga@ibim.cnr.it
W.E.G. M€ uller (ed.), Molecular Biomineralization, Progress in Molecular
and Subcellular Biology 52, DOI 10.1007/978-3-642-21230-7_8,
# Springer-Verlag Berlin Heidelberg 2011
225