A survey of internet resources for mouse development

The Internet contains many sources of information useful for mouse developmental biology research. These include anatomical atlases, gene expression atlases, and indexes to genetically engineered mouse strains and embryonic stem (ES) cells. Online atlases supersede earlier printed atlases in the quantity of available online images and the depth of specialized anatomical terminology and gene ontologies. Atlases annotated with gene expression data have increased value for comparisons with mouse models designed to study genetic perturbations of developmental processes. Gene expression libraries and microarray analyses of developmental stages are also available in Internet repositories. Bioinformatic interrogation of this data can identify regulatory gene networks and suggest putative transcriptional regulators that control cell fate. In silico formulated hypotheses about regulatory genes may be tested in vivo with mouse models obtained from the international Knockout Mouse Project (KOMP). Many of the genes targeted ES cells in KOMP are designed to mark cells with reporter molecules and produce conditional alleles. In combination with Cre recombinase mouse strains, genes can be inactivated at different developmental stages in specific cell types to study their function in embryogenesis. Atlases of mouse development, gene expression atlases, transcriptome databases, and repositories of genetically engineered mouse strains and ES cells are discussed.