Our main focus is the Gene Expression Database (GXD), which captures and integratesmouse expression data generated by biomedical researchers worldwide, with particularemphasis on mouse development. Gene expression data can provide researchers withcritical insights into the function of genes and the molecular mechanisms ofdevelopment, differentiation and disease. By combining different types of expressiondata and adding new data on a daily basis, GXD provides increasingly completeinformation about expression profiles of transcripts and proteins in wild-type and mutantmice. We work closely with the other Mouse Genome Informatics (MGI) projects toprovide the community with integrated access to genotypic, expression and phenotypic,and disease-related data. Thus, one can search for expression data and images in manydifferent ways, using numerous biologically and biomedically relevant parameters.