Fig 2. Her6/Hes1 is reduced in regenerating progenitors.

(A, B) Schematic representation of retinal cells and observed regenerative processes and timeline. Rod (purple) and cone (blue) photoreceptors (PR) are located in the outer nuclear layer (ONL). Müller glia (MG) are located in the inner nuclear layer (INL) with processes spanning across the retina from the ONL through to the GCL (ganglion cell layer). Following PR ablation, MG are activated and dedifferentiate into progenitors, which proliferate and migrate prior to differentiation into photoreceptors by 96 hours post ablation (hpa). (C-H”) In adult retina, during the 96-hour regenerative time span following the ablation of PRs (red), proliferation is marked by proliferative cell nuclear antigen (PCNA, pink) starts at 24 hpa. Expression of Hairy-enhancer of split (Hes1, green) is seen both in the control and following the ablation in the inner half of the INL and in the GCL. Focusing on the proliferative cells, the expression of Hes1 is downregulated as PCNA expression increases from 24 hpa onwards. DAPI (cyan) marks the retinal layers. Scale bars: 50 μm.(I) UMAP plot of FACS MG 3 days after injury is subdivided into distinct MG derived cell populations based on stereotypical markers. (J) The feature plots show that her6 is expressed mainly in the quiescent and some proliferating MG (pcna, ascl1a expressing) subsets and downregulated in differentiating (pcna, insm1a expressing) cell populations. (K) Summary of Hes1/her6 expression during regeneration. Hes1/her6 is present in the initial progenitors and downregulated upon their proliferation.