(A) Comparison of ME31B binding and translational efficiency. Plotted are the ME31B binding and translation efficiency values for each gene expressed above cut-off in 2–3 and 3–4 hr embryos. (B) Comparison of ME31B binding and RNA stability. At each of the indicated time points, the RNA fold change over the next hour was determined. For instance, the RNA fold change between 1–2 hr and 0–1 hr was calculated and compared with ME31B binding at 0–1 hr. Plotted are the ME31B binding and fold-change values for each of the indicated time points. (C) Comparison of ME31B binding and translational efficiency in png50 embryos. Plotted are the ME31B binding and translational efficiency values for each gene expressed above cut-off in 0–1 hr eGFP-me31B; png50 embryos (ME31B binding) and 0–1 hr png50 activated eggs (translational efficiency). (D) Comparison of RNA abundance in wild-type embryos. Plotted are the RNA abundances for each gene in 0–1 hr and 2–3 hr wild-type embryos. (E) Comparison of RNA abundance in png50 embryos. Plotted are the RNA abundances for each gene in 0–1 hr and 2–3 hr png50 embryos. (F) Model for the role of ME31B during early development. Prior to the MZT, ME31B, TRAL, and Cup are highly associated with eIF4E and PABP, and ME31B binding represses translation of many transcripts. During the MZT, protein and mRNA levels of Cup, TRAL, and ME31B decrease, and the binding of ME31B now requires recruitment via trans-factors, such as SMG. As indicated by the dotted line, this recruitment is likely indirect presumably relying upon interactions between trans-factors and the CCR4-NOT deadenylase complex and subsequent binding of ME31B and CNOT1. By the end of MZT, ME31B is no longer associated with PABP, and it promotes mRNA decay likely by recruitment of the decapping enzyme (through TRAL, EDC3, and/or HPat).