Journal: Cell Reports

Article Title: Spatiotemporal coordination of Slit-Robo repulsion and neurturin-Gfrα attraction guides multipolar migration during retinal lamination

doi: 10.1016/j.celrep.2026.116948

Figure Lengend Snippet: Multipolar horizontal cell navigation is not affected by bipolar cell absence or partial photoreceptor loss (A) Schematic of multipolar horizontal cell (HC, cyan) migration in the developing zebrafish retina, relative to RGCs (red), ACs (yellow), PRs (magenta), and BCs (purple). See A. (B) Time series of HC (cyan/yellow; white arrow) multipolar migration from the basal AC layer (cyan and yellow) toward the PRs, culminating in lamination below the PR layer (magenta). RGC layer (yellow) resides below the ACs. Tg(atoh7:gap-RFP) labels all retinal neurons except BCs; Tg(ptf1a:Gal4; UAS:gap-YFP) labels ACs and HCs, and Tg(crx:gap-CFP) labels PRs and faintly BCs. Scale bars: 20 μm. See . (C) Lamination of BCs (gray), Acs, and HCs (yellow) at 54 hpf. Dotted line area marks the PR layer. Right: magnified view showing migrating HCs (white arrows) between BCs. Tg(vsx1:GFP) marks BCs, and Tg(ptf1a:DsRed) marks ACs and HCs. Scale bars: 20 and 5 μm, respectively. (D) HC and AC lamination at 80 hpf in control and vsx1 + vsx2 F0 KO embryos lacking BCs. In contrast to the control (i), in the KO retina (ii), the AC layer (yellow) extends into the presumptive BC layer (dashed line). Tg(lhx1:GFP) labels HCs, and Tg(ptf1a:DsRed) labels ACs and HCs. Scale bars: 20 μm. See B and . (E) HC (cyan, white arrows) migration in control and prdm1b F0 KO embryo showing gaps in the PR layer (magenta and yellow). Zpr-1 labels PRs, Tg(lhx1:GFP) labels HCs, Tg(atoh7:gap-RFP) labels PRs, HCs, and RGCs. Scale bars: 20 μm. See and D and S1E. (F) Quantification of HCs >5 μm away from the PR layer in laminated retinae of different genetic conditions. N = 31 (control, scrambled KO), 17 ( vsx1 + vsx2 ), and 23 ( prdm1b ). p values (Mann-Whitney test vs. scrambled KO) = 0.0029 ( vsx1 + vsx2 ∗∗ ); <0.0001 ( prdm1bI ∗∗∗∗ ). Boxes show interquartile range; center line = median; whiskers = min/max; dots = individual retinae.

Article Snippet: Tg(lhx1:GFP) or Tg(ptf1a:Gal4; UAS:gap-YFP) embryos grown to 52- and 54 hpf in the presence of 0.2 mM PTU, were fixed overnight at 4°C with 4% PFA and expanded using an adapted UltraExM protocol based on., , , Prior expansion, the Tg(ptf1a:Gal4; UAS:gap-YFP) embryos were stained with 1:200 GFP (50430-2-AP, Proteintech) whereas the Tg(lhx1:GFP) embryos were processed straight for expansion.

Techniques: Migration, Control, MANN-WHITNEY

Journal: Cell Reports

Article Title: Spatiotemporal coordination of Slit-Robo repulsion and neurturin-Gfrα attraction guides multipolar migration during retinal lamination

doi: 10.1016/j.celrep.2026.116948

Figure Lengend Snippet: Multipolar horizontal cells use protrusions and navigate along repulsive Slit-Robo and attractive neurturin signaling (A) Chromobody (CB)-labelled F-actin (UAS:ActinCB-TagGFP2; ptf1a:Gal4, cyan) in apically migrating HCs at 54 hpf. Dashed line marks the PR layer. DAPI (gray) labels nuclei. Scale bar: 5 μm. (B) Migrating HCs (cyan, magnified white dashed box) with protrusions (white arrows) contacting PRs (magenta) at 54 hpf. Tg(atoh7:gap-RFP, yellow) , Tg(ptf1a:Gal4; UAS:gap-YFP, cyan) , and Tg(crx:gap-CFP, magenta) . Scale bars: 20 and 10 μm respectively. See B and . (C) Expansion microscopy of HC ( Tg(ptf1a:Gal4; UAS:gap-YFP) protrusions. (i) 3D rendering showing an HC (cyan) protrusion touching the PR layer (white dashed line). (ii) HCs (fire) migrating between neighboring cells with a protrusion (magnification of boxed area) extending between two cells labeled with F-actin (white). Nuclei stained with DAPI (gray/blue). Scale bars: 20 μm. See and A. (D) prdm1b KO in a robo2 F1 background at 80 hpf. Areas with a more intact PR layer (solid line; i) reproduce the robo2 KO phenotype, whereas areas with absent or abnormal PR layer (dashed line; ii) show enhanced HC retention in the AC layer. Magnified areas (white boxes; i/ii); PR cell layer (white arrowheads). Tg(ptf1a:DsRed, yellow) labels ACs and HCs, and Tg(lhx1:GFP, cyan) labels HCs. DAPI (gray) marks nuclei. Scale bars: 20 μm. See E. (E) Neurturin ( nrtn + nrtn-like ) KO in a robo2 F1 causes near-complete HC (cyan and yellow) retention in the AC layer (yellow) at 80 hpf. Other retinal layers are similar to controls. DAPI (gray) marks nuclei. Scale bars: 20 μm. See B, S4C, and S4E and . (F) Ret KO in robo2 F1 phenocopies neurturin depletion, causing most HCs (cyan and yellow) to remain in the AC layer (yellow) at 80 hpf. Nuclei were stained with DAPI (gray). Scale bars: 20 μm. See C. (G) Transplantation of control cells Tg(H2A.F/Z:GFP, cyan nuclei) into neurturin KO robo2 F1 Tg(lhx1:GFP, cyan), Tg(ptf1a:DsRed, yellow) . Around areas with control cells (ii and iv, magnified from white boxes), more Robo2-lacking recipient HCs (cyan and yellow) reach control PRs (white arrows), compared to areas without donor cells (i and iii, magnified from orange boxes). Scale bars: 20 μm. See C and F. (H) Quantification of HCs remaining in the AC layer (>5 μm away from PRs) after the depletion of attractive cues alone or combined with Robo2 loss. N = 31 ( scrambled KO), 15 ( ntf3 KO), 17 ( nrtn + nrtn-like KO), 33 ( ret KO), 43 ( robo2 F1), 13 ( prdm1b KO in Robo2 F1), 28 ( nrtn + nrtn-like KO in robo2 F1), 32 ( ntf3 KO in Robo2 F1), and 28 ( ret KO in Robo2 F1). p values (Mann-Whitney test) = 0.3531 ( ntf3 KO vs. scrambled KO) ns, 0.0684 ( nrtn + nrtn-like KO vs. scrambled KO) ns, 0.4805 ( ret KO vs. scrambled KO) ns, <0.0001 ( prdm1b KO in robo2 F1 vs. robo2 F1) ∗∗∗∗ <0.0001 ( nrtn + nrtn-like KO in robo2 F1 vs. robo2 F1) ∗∗∗∗ <0.0001 ( ntf3 KO in robo2 F1 vs. robo2 F1) ∗∗∗∗ <0.0001 ( ret KO in robo2 F1 vs. robo2 F1) ∗∗∗∗ 0.7037 ( prdm1b KO vs. nrtn + nrtn-like KO in robo2 F1) ns, and 0.9835 ( prdm1b KO vs. ret KO in robo2 F1) ns. Boxes show interquartile range; center line = median; whiskers = min/max; dots = individual retinae. (I) Schematic of guidance cues coordinating multipolar HC navigation. At 48 hpf, ACs start to express Slit1b and Slit2 to repulse Robo2 expressing HCs toward the PRs. Concurrently, PRs initiate the expression of secreted neurturin to further attract HCs positive for the Gfrα1/2-Ret receptor complex toward the PR layer.

Article Snippet: Tg(lhx1:GFP) or Tg(ptf1a:Gal4; UAS:gap-YFP) embryos grown to 52- and 54 hpf in the presence of 0.2 mM PTU, were fixed overnight at 4°C with 4% PFA and expanded using an adapted UltraExM protocol based on., , , Prior expansion, the Tg(ptf1a:Gal4; UAS:gap-YFP) embryos were stained with 1:200 GFP (50430-2-AP, Proteintech) whereas the Tg(lhx1:GFP) embryos were processed straight for expansion.

Techniques: Microscopy, Labeling, Staining, Transplantation Assay, Control, MANN-WHITNEY, Expressing