Set8a participates in Wnt signaling to regulate zebrafish embryonic development. (A) set8a MO led to H4K20me-1 reduction at tbx6 TBE. Zebrafish embryos were injected with distinct set8a or wnt8 MOs at one-cell stage and collected at shield stage for ChIP experiment. Quantitative PCR results of IgG were set as 1. P values were calculated between control MO and set8a or wnt8 MO injection. **P < 0.01. (B) Morphology of set8a (0, S1, S2, and S3) and wnt8 (0, W1, W2, and W3) morphants at 26 hpf. The wnt8 morphants were classified into four categories, with 0 being WT and W3 being the most severe phenotype. The set8a morphants were classified into four categories, with S1 displaying relatively small head, S2 displaying small head and shortened trunk and tail, and S3 displaying small head and severely shortened trunk and tail. (C) SET8-114 mRNA restored the set8a MO phenotype. The number of embryos scored (N) is shown on top of each bar, and the concentration of MO is indicated. The morphant phenotypes were classified into four categories: 0, S1, S2, and S3. (D) set8a MO enhanced the neuroecodermal and mesodermal defect of wnt8 MOs. Embryos were examined at the 10-somite stage. In situ markers used were opl (telencephalon), pax2.1 (midbrain/hindbrain boundary), and myod (adaxial cells and somites). Red arrowheads, opl expression; black arrowheads, notocord. (E) SET8-114 mRNA but not 114H299A rescued the synergistic effect of set8a MO and wnt8 MOs. The morphants phenotypes were classified into four categories: 0, W1, W2, and W3.