Figure 4.

Transcription and signalling pathways regulate and limit proliferating RSC/RPCs to the CMZ. A summary of the complex regulation and inter-connected regulation of the CMZ niche—a region where multiple pathways collide. Shown is the known effect of transcriptional regulation (HDAC inhibitors, dnmt1, Chx10/vsx2, Pax6, rx2, Six3/Six6, Atoh7) and signalling pathways (Shh, glucagon, IGF-1, Wnt and Notch) presented in this review and how they converge onto the different aspect of RPC regulation- survival, stemness, proliferation and multilineage potential (grey categories presented on the right). The green circles highlight different hubs of signalling/transcriptional networks that positively regulate RSC/RPCs. Pink circles, however, negatively regulate RSCs/RPCs. Similarly, factors with pink lettering are used to represent factors that negatively regulate their downstream targets. Arrowheads at the ends of the line indicate a positive regulation, whereas blunt line ends represent negative regulation. Solid lines indicate linear relationships, whereas dashed lines indicate relationships between the hubs (i.e., between Shh and Wnt signalling or Notch and Wnt signalling). If any relationship is unknown or questioned due to inadequate evidence, a question mark is used to represent this uncertainty.