Fig 2: Atypical spindle cells accumulate in the choroid rete of brca2 m/m;tp53 m/m zebrafish. (a) The choroid rete (outlined in green) is a vascular plexus located subjacent to the choroid. (b) Normal choroid rete. (c) Choriod rete containing numerous atypical spindle cells (green arrows). (d) Numbers of zebrafish that developed atypical spindle cells in the choroid rete over time (n = 4 per genotype at each time point analyzed). (e) Numbers of zebrafish that received optic nerve injury and developed atypical spindle cells in the choroid rete. (f) Atypical spindle cells in the choroid rete are sox10-positive (brown chromogen). Red arrows delineate margins of choroid rete. Area boxed in red is shown at higher magnification to the right. (g) Small numbers of sox10-positive cells (brown chromogen) are present in the normal choroid rete. Red arrows delineate margins of choroid rete. Area boxed in red is shown at higher magnification to the right. Red circles identify sox10-positive cells. Ret, retina; RPE, retinal pigmented epithelium; CR, choroid rete; ON, optic nerve. Scale bar = 50 µm (panel a); 20 µm (panels b, c, f, h).

Fig 3: Sox10-expressing cells are required for cartilage regeneration. (A) Genetic ablation model. (B) Timeline for treatment and analysis. (C,D) Antibody and TUNEL staining of the adult jaw joint shows mCherry expression in sox10:mCh-NTR adult joint cells and apoptotic cells in metronidazole (Mtz)-treated animals at (D) 3 days after Mtz treatment (days post-ligament transection, dplt). (E,F) Toluidine blue staining of joints at 42 dplt without (E) or with Mtz treatment (F) prior to ligament injury (insets in E' and F' show the details of the articular surface). (G) OARSI scoring of joint integrity following Mtz treatment and/or ligament injury. Individual data points, mean, and standard error of the mean are shown. The p-values are calculated by Kruskal–Wallis ANOVA and Dunn’s multiple-comparison test. Scale bars = 50 µm.

Fig 4: lats2 CRISPR-injected fish tumors bear markers supporting PNST diagnosis. (A,A’) Representative images of Sox10 immunohistochemical staining in lats2 CRISPR-injected fish. (B,B’) Representative images of S100 immunohistochemical staining in lats2 CRISPR-injected fish. (C,C’) Representative images of PCNA immunohistochemical staining in lats2 CRISPR-injected fish Scale = 2.5 mm for A–C, and 100 µm for A’–C’. Boxes in A–C denote the tumor area shown at higher magnification in A’–C’.

Fig 5: Optic nerve injury (ONI) and brca2 genotype exert variable effects on the development of proliferative and neoplastic lesions in the optic nerve pathway. (a) The majority of zebrafish ocular tumors highly express sox10 regardless of ONI status. White arrows indicate dispersed melanin pigment within tumors. Inset shows tumor cells with positive nuclear sox10 expression (brown chromogen). Asterisk indicates a blood vessel containing nucleated erythrocytes that do not express sox10. (b) In zebrafish that received ONI, most brca2 m/m;tp53 m/m zebrafish developed atypical spindle cells in the choroid rete (CR) on the injured side (ONI side) or bilaterally, in contrast to ocular tumor development. (c) In zebrafish that received ONI, brca2 m/m;tp53m/m zebrafish were more likely to develop ocular lesions (ocular tumor and/or hyperplastic spindle cells in the choroid rete) and these lesions were more likely to be bilateral. HE, hematoxylin and eosin; Ret, retina; RPE, retinal pigmented epithelium; ONI, optic nerve injury; CR, choroid rete. Scale bar = 50 µm.