Model for regulation. An ambitious plan to map the genome's regulatory elements will focus first on mouse embryonic stem cells.

Onward to the Regulome

OTTAWA, CANADA--Dozens of the world's leading molecular biologists have banded together to map out the biochemical instructions that allow organisms to make all the types of cells they need. The Canada-based effort, called the International Regulome Consortium, hopes to raise $100 million in public funding for what organizers are calling "the third generation of genomics."

The new consortium proposes to characterize and tag the 1486 known transcription factors--proteins that switch genes on and off--in the mouse genome, as well as an estimated 600 coregulators that chip in to control cellular and biological functions through networks called regulons. The entire cast of actors is known as the regulome. Roughly 75 researchers from six nations (Canada, the United States, the United Kingdom, France, Italy, and Singapore) began sketching the parameters of their plan during a founding workshop held here 3 to 5 May. They hope to identify the complete set of DNA binding sites and corresponding target genes for the regulons in embryonic stem cells and a subset of the cells they differentiate into.

The mouse regulome is the obvious choice to focus on, says William Skarnes, senior scientist at the Wellcome Trust Sanger Institute in Cambridge, U.K., given the vast amount of data already available on the animal and its similarity to humans. Still, the genetic homogeneity of largely inbred mouse strains may be misleading when it comes to understanding human stem cells, cautions Peter Andrews, professor of biomedical science and co-director of the Centre for Stem Cell Biology at the University of Sheffield, U.K. "In the human, every embryonic stem cell that we're working with that comes from a different person is genetically different," says Andrews. "We don't know, at the moment, what significance that genetic heterogeneity will have."

Consortium members hope that governments will provide support to help the group get organized as well as for ongoing operations and research. Understanding how a set of genes is regulated during development of an organism, or during disease, "will revolutionize our understanding of how cells function," says Michael Rudnicki, senior scientist at the Ottawa Health Research Institute, who is chairing a steering committee that will manage the effort.