Experimental set up and overall expression profiles. (a) The time course of gene expression was determined during the response of two different fibroblast types; 2091 derived from foreskin and WI-38 derived from fetal lung. Each was treated with either the indicated GFs, epidermal growth factor (EGF), fibroblast growth factor (FGF), platelet derived growth factor (PDGF) or FBS (Serum), and three replicate time courses were run for each treatment. The layout of the samples in the other panels as well as in Figures 2-6 is as shown here. (b) Hierarchical cluster of 1,304 genes with a minimum expression change of twofold in at least 15 array experiments and with data present in at least 80% of all array samples. cDNAs with no known Unigene annotation or mapping to multiple Unigene clusters were removed. Black bars on the right indicate consistently induced genes. (c) Sub-cluster branches containing the consistently induced genes were selected and re-clustered. This set included 237 genes represented by 278 cDNA probes. (d) Consistently repressed genes were selected directly from expression data as described in Materials and methods and clustered. This set included 237 genes represented by 250 cDNA probes.