Figure 5. Summary schematic conveying Kruppel-like factor 9 (Klf9) functions in radial-glial neural stem cell (RGL) activation and self-renewal RGLs integrate extracellular, experiential signals to exit quiescence, the dominant state, and become activated.

Klf9 expression is elevated in quiescent RGLs. Low levels of Klf9 in RGLs are associated with increased activation. Once activated, RGLs lacking Klf9 are biased toward symmetric self-renewal and RGL expansion. Translational profiling of RGLs reveals how loss of Klf9 results in downregulation of a program of quiescence and activation of genetic (mitogen, notch) and metabolic (fatty acid oxidation and lipid signaling) programs underlying RGL symmetric self-renewal. Candidate differentially expressed upregulated (orange) and downregulated genes (blue) in RGLs following Klf9 deletion are shown here. Genes in bold indicate validation by qRT-PCR.