A view from the genome: spatial control of transcription in sea urchin development

The process of embryogenesis depends on differential regulation of genes in the spatial components defined by the embryonic cells (blastomeres). Devel opmental regulation is mediated by complex, hardwired genomic control syste ms consisting of clusters of multiple target sites at which specific intera ctions with regionally presented transcription factors occur. In the age of genomics and gene-transfer technology, the sea urchin embryo provides uniq ue opportunities for experimental analysis of these processes. Research on gene regulation in sea urchin embryos in the past year has seen remarkable progress in two large areas: in understanding functional cis-regulatory arc hitecture; and in understanding the mechanism by which the axial coordinate s of the egg are transduced into a molecular system for differential gene a ctivation.