Fig. 3.

Transient overexpression of SHFM hPRDM1 variants fails to rescue the pectoral fin in prdm1a^−/− mutants. prdm1a^+/− heterozygous fish were intercrossed and injected with the hPRDM1 WT and SHFM variant mRNAs at the single-cell stage. Injected larvae were collected at 4 dpf for Alcian Blue staining. (A-F) Representative images of Alcian Blue-stained pectoral fins at 4 dpf. (A) Uninjected WT/heterozygous (n=18). (B) Uninjected prdm1a^−/− mutant (n=9). (C-F) prdm1a^−/− mutants were injected with (C) WT hPRDM1 (n=10), (D) hPRDM1(p.C239Lfs*32) (n=10), (E) hPRDM1(p.T524R) (n=8) or (F) hPRDM1(p.T819A) mRNA (n=7). The representative uninjected control images in A and B are also used in Fig. S3, which shows the effect of overexpression of hPRDM1 variants in the WT background as part of the same experiment. Scale bars: 50 µm. (G-I) Measurements for the lengths of the (G) cleithrum, (H) endoskeletal disk and (I) fin fold and (J) the area of the scapulocoracoid and postcoracoid were averaged and compared using a one-way ANOVA, followed by a Tukey post-hoc test relative to uninjected prdm1a^−/− mutants. Each dot represents one independent biological replicate. P-values are shown in the figure. Injection of WT hPRDM1 partially rescued the cleithrum, endoskeletal disk and fin fold of prdm1a^−/− mutants. However, overexpression of the three SHFM variants failed to rescue the pectoral fin. Error bars represent the mean±s.d. cl, cleithrum; D, distal; ed, endoskeletal disk; ff, fin fold; Het, heterozygous; hpf, hours post fertilization; MT, prdm1a^−/− mutant; P, proximal; pc, postcoracoid; sc, scapulocoracoid; WT, wildtype.