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. 2013 Feb 15;140(4):719–729. doi: 10.1242/dev.083741

Fig. 7.

Fig. 7.

pbx is required for maintenance of pole gene expression and eyes during homeostatic tissue turnover. (A) Six weeks of prep and pbx RNAi caused reduced sFRP-1 expression (control, n=0/13; prep RNAi, n=13/13; pbx RNAi, n=10/10) and aberrant wnt-2 (control, n=0/4; prep RNAi, n=3/3; pbx RNAi, n=3/3) and notum (control, n=0/6; prep RNAi, n=6/6; pbx RNAi, n=3/3; white circle) expression. pbx RNAi, but not prep RNAi, caused wnt1+ cell reduction at the posterior pole (control, n=7; prep RNAi, n=7; pbx RNAi, n=6; shown are mean±s.e.m.; one-way ANOVA test followed by a Dunnet post-hoc test; *P≤0.05 between experimental condition and control). pbx(RNAi) animals, labeled with α-ARRESTIN antibody gradually lost photoreceptors and prep(RNAi) animals exhibited extra photoreceptors (white arrow) (control, n=6; prep RNAi, n=6; pbx RNAi, n=3). Asterisks in images indicate eyes. Scale bars: 50 μm. (B) Unamputated pbx(RNAi) animals failed to homeostatically maintain photoreceptor neurons after 8 weeks of RNAi (labeled with α-ARRESTIN antibody; pbx RNAi, n=8/10; control, n=0/10). Scale bars: 50 μm. (C) Control, prep or pbx RNAi animals at 6 days of regeneration. Blastema size quantification is shown at right (one-way ANOVA test followed by a Dunnet post-hoc test; ***P≤0.001 between experimental condition and control; n=10 for each condition). Dorsal expression of nlg-8 and ventral expression of netrin in trunk anterior blastemas (n=14/14 for all conditions). Both prep and pbx RNAi animals exhibited aberrant wnt-2 expression at the anterior tip of all regenerating pieces (control, n=0/16; prep RNAi, n=16/16; pbx RNAi, n=11/12). However, only pbx(RNAi) animals showed aberrant wnt-2 expression at posterior blastemas (control, n=1/16; prep RNAi, n=1/16; pbx RNAi, n=11/12). Black arrows, normal expression; red arrows, aberrant expression. Neoblasts (smedwi-1+) were similar in distribution among all RNAi treatments (control RNAi n=15/15; prep RNAi n=16/16; pbx RNAi, n=14/14 regenerating pieces; shown are mean±s.e.m.). Scale bars: 100 μm. (D) Data summary. pbx is required for expression of anterior and posterior pole genes in head and tail blastemas, respectively. pbx is also required for eye progenitor formation. Dashed lines indicate animal boundaries. All animals are oriented with anterior to the top.