(A) O2-dependent regulation of HIF-1α stability. Under normoxic conditions, HIF-1α is hydroxylated (-OH) by prolyl hydroxylase (PHD), leading to association with von Hippel-Lindau (VHL) protein and rapid proteasomal degradation. Under hypoxic conditions, HIF-1α is not hydroxylated and binds to HIF-1β (ARNT) to regulate target gene transcription through HRE (HIF response elements) in promoter regions. bHLH, basic helix-loop-helix; PAS, Per-Arnt-Sim; ODD, oxygen-dependent degradation domain; TAD, transactivator domain. (B) HIF-1α expression in SVZ under non-pathological conditions. Tangential section through adult mouse SVZ demonstrating localization of HIF-1α immunofluorescence (red) under non-pathological conditions (blue, DAPI nuclear stain). Scale bar= 20μm. For methodological details, please see Roitbak et al. [26]. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of the article.)