Figure 4. Transcriptional profiling of rapamycin-exposed SSCs reveals an upregulation of oxidative stress response genes. (A) Double-log scatter plot to visualize the signal intensities of all oligo probes on the Agilent Whole Mouse Genome oligonucleotide microarray 4x44K platform that were upregulated (red crosses), downregulated (green crosses), or unchanged (blue crosses). Filter conditions applied to the scatter plot: >2-fold change and p-value <0.01. (B) Heat map of genes within a cluster containing Gfra1 that were significantly altered in THY1+/GFRA1+ cells in response to rapamycin exposure. Horizontal stripes represent genes and columns show the treatment conditions (VEH = control vehicle; RM = rapamycin). Log2-fold changes of gene ratios are color coded as shown in the top horizontal stripe, from a relative low value of 0.0 (green) to a high of 20.0 (red). (C) Potential relationships among the antioxidant gene products of Sod1, Gsr, and Alad in rapamycin-exposed SSCs, illustrated here as a schematic adapted from Ingenuity Pathways Analysis® (IPA). Parallelograms represent enzymes, ovals represent transcription factors, squares represent cytokines, and inverted triangles represent cell receptors. Solid lines indicate direct binding (only) between gene products, while dashed lines represent indirect associations. Arrows indicate that the first product acts upon the second product. A circular solid line with arrow represents direct auto regulation. Fold changes and p-values are listed next to the gene products.