Figure 2.

Hierarchical clustering analysis of genes responding to biomechanical stimulation in cultured endothelial cells. Named genes whose mRNA levels showed significant up- or down-regulation (≥2-fold) and whose level of expression was ≥1,500 under laminar vs. static or turbulent vs. static conditions were selected. These 143 genes were clustered hierarchically into groups on the basis of the patterning of their expression profiles, by the procedure of Eisen et. al. (17). Each column represents a single experiment, and each row represents a single gene. For each gene, the ratio of mRNA levels for LSS/static conditions and TSS/static conditions, is denoted by a color code. Blue squares represent lower than static levels of gene expression in the LSS or TSS samples (ratios less than 1); white squares represent genes equally expressed (ratios near 1); red squares represent higher than static levels of gene expression (ratios greater than 1). Color saturation reflects the magnitude of the log/ratio (see color scale). Full cluster diagram with complete names and accession numbers is available at http://vessels.bwh.harvard.edu/papers/PNAS2001.