Activation of erythroid genes by GATA-1 in G1E-ER4 cells. Each column represents a time point from 0 to 30 hours after GATA-1 activation, and each row is assigned to a transcript. The color scale ranges from blue to red, corresponding to values ranging from –2.5 to +2.5 standard deviations about each transcript's mean, with white representing the mean value. Hence, a shift from blue to red indicates induction. Signal values (average of 3 triplicates) at 0 and 30 hours are shown in parentheses; these correspond roughly to transcript abundance. Transcripts shown here underwent at least a 2-fold change from time zero and had an average signal value of at least 100 in at least one time point.