Fig. 1: 4E-T depletion triggers spontaneous meiotic resumption and accelerates hormone-induced meiotic maturation.

a Xenopus stage-VI oocytes were injected with the indicated 4E-T or unspecific control (Ctrl) antibodies and mRNA encoding Flag-TRIM21. Samples were taken 22 h after injection and immunoblotted as indicated. One representative experiment of three independent biological replicates is shown. b Xenopus stage-VI oocytes were injected with water or mRNA encoding Flag-4E-T^TRIM. 18 h after injection, oocytes were co-injected with mRNA encoding Flag-TRIM21 and either 4E-T^Ab1 or unspecific control (Ctrl) antibodies. 35 h after the second injection, the occurrence of GVBD was determined by the appearance of a white spot in the animal hemisphere of the oocytes (Ctrl TRIM + H₂O, n = 107 oocytes; 4E-T^Ab1 TRIM + H₂O, n = 105 oocytes; 4E-T^Ab1 TRIM + Flag-4E-T^TRIM, n = 104 oocytes). Percentage of oocytes with GVBD spots is given as mean ± s.d. from four independent biological replicates. p-values were calculated using one-way ANOVA with Tukey’s multiple comparisons test. c Mouse oocytes were injected with the indicated 4E-T or unspecific control (Ctrl) antibodies and mRNA encoding mouse TRIM21. Samples were kept in medium containing 10 µM RO-3306 for 6 h after injection and immunoblotted as indicated. One representative experiment of two independent replicates is shown. d Representative stills from time-lapse movies of control and 4E-T-depleted mouse oocytes stained with 5-SiR-Hoechst. Oocytes were incubated with dbcAMP as indicated. Cyan, DNA. Arrowheads indicate oil droplets injected to ensure quantitative microinjections. e Percentage of control and 4E-T-depleted mouse oocytes that resume meiosis (upper panel) or extrude polar bodies (lower panel) in the presence or absence of dbcAMP. Data are from four (upper panel) or two (lower panel) independent experiments. f TRIM-Away of 4E-T and expression of Flag-4E-T^TRIM was performed as described in (b). 22 h after the second injection, oocytes were lysed for immunoblotting as indicated. One representative experiment of three independent biological replicates is shown. g Oocytes from (f) (Ctrl TRIM + H₂O, n = 76 oocytes; 4E-T^Ab1 TRIM + H₂O, n = 68 oocytes; 4E-T^Ab1 TRIM + Flag-4E-T^TRIM +, n = 75 oocytes; 4E-T^Ab1 TRIM + Flag-4E-T^TRIM ++, n = 72 oocytes) were treated with PG 22 h after the second injection. Percentage of oocytes undergoing GVBD in 760 min after PG addition and median time to GVBD are given as mean±s.d. from three independent biological replicates. p values were calculated using one-way ANOVA with Tukey’s multiple comparisons test. h Upper panel: Scheme of c-Mos expression, Cdk1 and MAPK activation as shown by loss of inhibitory and gain of activating phosphorylation, respectively, during prophase-I arrest and oocyte maturation. TRIM-Away of 4E-T and expression of Flag-4E-T^TRIM was performed as described in (b). 22 h after the second injection, oocytes were treated with PG, samples were taken at the indicated time points and immunoblotted as indicated. One representative experiment of three independent biological replicates is shown. i, j Experiment was performed with the indicated Flag-4E-T^TRIM constructs as described in (f, g). Oocytes (Ctrl TRIM + H₂O, n = 105 oocytes; 4E-T^Ab1 TRIM + H₂O, n = 111 oocytes; 4E-T^Ab1 TRIM + Flag-4E-T^TRIM, n = 94 oocytes; 4E-T^Ab1 TRIM + Flag-4E-T^TRIM 1-319, n = 101 oocytes) from four independent biological replicates were analyzed. Percentage of oocytes undergoing GVBD in 460 min after PG addition and median time to GVBD are given as mean±s.d. p values were calculated using one-way ANOVA with Tukey’s multiple comparisons test. Source data including additional loading controls are provided as a Source Data file.