ubr3 is required for Hedgehog (Hh) signaling in zebrafish.
(A, C) DIC images show lateral views of posterior trunk regions at 24-hours-post-fertilization. Anterior to the left, dorsal up. The angles of V-shaped somites were shown by the red line. Scale bars: 50µm. (B, D) islet2 in situ hybridization (ISH) of wild type and ubr3b1250/1251 mutant zebrafish. Lateral views of posterior trunk regions at 24-hours-post-fertilization are shown. (E) Average somite angle in wild-type siblings (wt sibs) and ubr3b1250/b1251 trans-heterozygous mutants. Wild type siblings have a typical V-shaped somite characterized by an average angle of 92°. In the ubr3 trans-heterozygous mutants, the angles become more obtuse with an average of 119°. (F-I) ISH against ubr3 at 24 and 28 hpf. Lateral views of the somites. (F-G) At 24 hpf (F), ubr3 is expressed throughout the somites. By 28hpf (G), this expression is restricted to ventral regions of the somites (red bracket). (H) ubr3 expression is lost in smo mutants at 24 hpf. (I) At 28 hpf, the ubr3 expression domain is expanded dorsally when Hh signaling is upregulated by ectopic expression of dnPKA (green bracket). Bars: SEM. Five angles were measured per larva. Five heterozygous and seven ubr3b1250/b1251 larvae were analyzed, P<0.01.