Phylogeny, in situ hybridization service Sign up for PNAS Online eTocs
Link: Info for AuthorsLink: Editorial BoardLink: AboutLink: SubscribeLink: AdvertiseLink: ContactLink: Sitemap Link: PNAS Home
Proceedings of the National Academy of Sciences
Link: Current Issue "" Link: Archives "" Link: Online Submission ""  Link: Advanced Search

Published online on April 14, 2008, 10.1073/pnas.0801201105
PNAS | April 22, 2008 | vol. 105 | no. 16 | 6091-6096


This Article
Right arrow Figures Only
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Supporting Information
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a colleague
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My File Cabinet
Right arrow Download to citation manager
Right arrow Request Copyright Permission
Citing Articles
Right arrow Citing Articles via CrossRef
Google Scholar
Right arrow Articles by Gao, F.
Right arrow Articles by Davidson, E. H.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Gao, F.
Right arrow Articles by Davidson, E. H.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg  
What's this?

 Previous Article  | Table of Contents |  Next Article 

BIOLOGICAL SCIENCES / EVOLUTION
Transfer of a large gene regulatory apparatus to a new developmental address in echinoid evolution

Feng Gao and Eric H. Davidson*

Division of Biology 156-29, California Institute of Technology, Pasadena, CA 91125

Contributed by Eric H. Davidson, February 5, 2008 (received for review October 24, 2007)

Of the five echinoderm classes, only the modern sea urchins (euechinoids) generate a precociously specified embryonic micromere lineage that ingresses before gastrulation and then secretes the biomineral embryonic skeleton. The gene regulatory network (GRN) underlying the specification and differentiation of this lineage is now known. Many of the same differentiation genes as are used in the biomineralization of the embryo skeleton are also used to make the similar biomineral of the spines and test plates of the adult body. Here, we determine the components of the regulatory state upstream of these differentiation genes that are shared between embryonic and adult skeletogenesis. An abrupt "break point" in the micromere GRN is thus revealed, on one side of which most of the regulatory genes are used in both, and on the other side of which the regulatory apparatus is entirely micromere-specific. This reveals the specific linkages of the micromere GRN forged in the evolutionary process by which the skeletogenic gene batteries were caused to be activated in the embryonic micromere lineage. We also show, by comparison with adult skeletogenesis in the sea star, a distant echinoderm outgroup, that the regulatory apparatus responsible for driving the skeletogenic differentiation gene batteries is an ancient pleisiomorphic aspect of the echinoderm-specific regulatory heritage.

embryonic and adult skeletogenesis | gene network evolution | sea urchin | sea star

Author contributions: F.G. and E.H.D. designed research; F.G. performed research; F.G. and E.H.D. analyzed data; and F.G. and E.H.D. wrote the paper.

The authors declare no conflict of interest.

This article contains supporting information online at www.pnas.org/cgi/content/full/0801201105/DCSupplemental.

*To whom correspondence should be addressed. E-mail: davidson{at}caltech.edu

© 2008 by The National Academy of Sciences of the USA


Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg    What's this?