On the Initiation of the Hard Tissues of Animals during the Late Precambrian to the Early Cambrian

Omori, Masae

doi:10.1007/978-4-431-68132-8_54

Cited by 1 publication

(1 citation statement)

References 11 publications

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“…Calcium carbonate deposition is an ancient mechanism of biomineralization (Mitterer 1989;Omori 1991;Marin et al 1996). The clone isolated in this study belongs to the a-class studied in mammalian systems (Sly and Hu 1995;Parkkila 2000), which have roles in cellular metabolism and transport (Henry 1996).…”

Section: Carbonic Anhydrasementioning

confidence: 99%

Gene expression patterns in a novel animal appendage: the sea urchin pluteus arm

Love

Andrews

Raff

2007

Evolution and Development

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The larval arms of echinoid plutei are used for locomotion and feeding. They are composed of internal calcite skeletal rods covered by an ectoderm layer bearing a ciliary band. Skeletogenesis includes an autonomous molecular differentiation program in primary mesenchyme cells (PMCs), initiated when PMCs leave the vegetal plate for the blastocoel, and a patterning of the differentiated skeletal units that requires molecular cues from the overlaying ectoderm. The arms represent a larval feature that arose in the echinoid lineage during the Paleozoic and offers a subject for the study of gene co-option in the evolution of novel larval features. We isolated new molecular markers in two closely related but differently developing species, Heliocidaris tuberculata and Heliocidaris erythrogramma. We report the expression of a larval arm-associated ectoderm gene tetraspanin, as well as two new PMC markers, advillin and carbonic anhydrase. Tetraspanin localizes to the animal half of blastula stage H. tuberculata and then undergoes a restriction into the putative oral ectoderm and future location of the postoral arms, where it continues to be expressed at the leading edge of both the postoral and anterolateral arms. In H. erythrogramma, its expression initiates in the animal half of blastulae and expands over the entire ectoderm from gastrulation onward. Advillin and carbonic anhydrase are upregulated in the PMCs postgastrulation and localized to the leading edge of the growing larval arms of H. tuberculata but do not exhibit coordinated expression in H. erythrogramma larvae. The tight spatiotemporal regulation of these genes in H. tuberculata along with other ontogenetic and phylogenetic evidence suggest that pluteus arms are novel larval organs, distinguishable from the processes of skeletogenesis per se. The dissociation of expression control in H. erythrogramma suggest that coordinate gene expression in H. tuberculata evolved as part of the evolution of pluteus arms, and is not required for larval or adult development.

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