Wnt/β-catenin signalling in stem cell zone 1 (qRG-L) and zone 2 (TMZi) following tectal lesion. (a) Experimental design to study Wnt/β-catenin signalling at 3-dpl. (b–d) Physiological levels of β-catenin expression in the neural layer (Neu-L) and qRG layer (qRG-L; stem cell zone 1). A small number of β-catenin-positive neuronal cell bodies are seen in the Neu-L (yellow arrow). White box depicts higher magnification images of the qRG-L in (c,d). Split-channel images showing co-labelling of qRG (c) and β-catenin (d; white arrows). (e–g) Lesion-induced β-catenin staining in the neural layer (Neu-L) and qRG layer (qRG-L) showing upregulation in the proportion of neuronal cells expressing nuclear β-catenin. White box depicts higher magnification images of the qRG-L in (f,g). Split-channel images showing co-labelling of qRG (f) and β-catenin (g; white arrow). (h–k) Common expression pattern of Wnt activity observed in the qRG-L between control (h,i) and at 3-dpl (j,k) using the Wnt reporter lines Tg(TCFSiam:mCherry) and Tg(top:GFP; white arrows). (l,m) β-catenin expression and EdU-labelling at the TMZi (stem cell zone 2; dashed white circles) under control conditions (l) and at 3-dpl (m, orange asterisk), showing increased nuclear expression in putative neurons post-lesion. (n–p) Homeostatic levels of axin2 expression in the qRG layer (o) and TMZi (p; black dashed circle). Black boxes in (n) denote higher magnifications in (o,p). (q,s)axin2 expression 3-dpl in the qRG layer (r) and TMZi (s; black dashed circle). Black boxes in (q) denote higher magnifications in (r,s). (t) Experimental design to study the requirement of Wnt/β-catenin signalling for the proliferative response of stem cells to tectal stab lesion using the heat-shock line Tg(hsp70l:dkk-1:gfp). (u) EdU population size in the qRG layer and TMZi shows no change in proliferation post-injury in the absence of Wnt signalling (dkk+) compared with wildtype animals (dkk-) using the Tg(hsp70:dkk-1:gfp) transgenic line (unpaired t-test, two-tailed: qRG layer, p = 0.3081; NE-Ap zone, p = 0.4960). (v-w”) Representative images of EdU+ staining (pink) in the qRG layer (dashed lines) in dkk- (control; v-v”) and dkk + (w-w”) post-lesion. (x-y”) Representative images of EdU+ staining (pink) in the TMZi (dashed lines) in dkk- (control; x-x”) and dkk + (y-y”) post-lesion. Orange asterisk denotes the lesioned hemisphere. Note GFP+ expression observed in the dkk + (w”,y”) but not dkk- (v”,x”). Experimental replicates were combined for all statistical analyses. All data presented are mean ± S.E.M. Significance was accepted at *p < 0.05. In panels b,e, v–y, DAPI nuclear counterstaining (blue) was performed. In all cross-sectional images dorsal is oriented up. TMZi, internal tectal marginal zone; dpl, days post lesion.
Acknowledgments
This image is the copyrighted work of the attributed author or publisher, and
ZFIN has permission only to display this image to its users.
Additional permissions should be obtained from the applicable author or publisher of the image.
Full text @ Sci. Rep.
Your Input Welcome
Thank you for submitting comments. Your input has been emailed to ZFIN curators who may contact you if
additional information is required.
Oops. Something went wrong. Please try again later.