Identification of genes regulated by hypoxia and HIF-1. (A) Experimental design and summary of results. The number inside the oval indicates the total number of gene probes on the microarray. Text in blue indicates the total number of gene probes showing a statistically significant difference between experimental conditions (1% O₂ vs 20% O₂; AdCA5 vs AdLacZ). The number in the box indicates the total number of gene probes with a statistically significant 1.5-fold or higher increase (red) or decrease (green) in expression in response to both 1% O₂ and AdCA5. (B) Volcano plot of 1% O₂ versus 20% O₂ data. For each gene probe, the log₂ (mean fold change in gene expression) is plotted on the x-axis and the log₂ (t test) is plotted on the y-axis. Blue dots represent gene probes with P > .05 by t test. Gray dots represent gene probes with P < .05. Green crosses indicate the 325 gene probes with a statistically significant 1.5-fold or higher decrease in expression in response to both hypoxia and AdCA5. Red crosses indicate the 245 gene probes with a statistically significant 1.5-fold or higher increase in expression in response to both hypoxia and AdCA5.