Figure 2.

Maternal deletion of Eif4e1b leads to developmental arrest at two cells. (A) Schematic of the Eif4e1b gene (top) and sequences of sgRNAs (bottom) for generation of Eif4e1b^KO mouse lines. (*) Initiator methionine, (x) stop codon. (B) Abundance of read overlaps with Eif4e1b exon 1 or 2. Residual Eif4e1b transcripts in Eif4e1b^KO female mice lack exons 1 and 2 and produce no functional eIF4E1b protein. (****) P < 0.0001; two-tailed t-test. (C) Six-week-old female Eif4e1b^Het (control) and homozygous Eif4e1b^KO mice were mated with WT males to determine litter sizes. (D). Accumulated pups from Eif4e1b^Het and Eif4e1b^KO females during 5 mo of continuous mating. (E) Representative images of in vitro cultured embryos from Eif4e1b^Het and Eif4e1b^KO females after mating with WT males at embryonic day 0.5 (E0.5), E1.5, E2.5, E3.0, and E4.0. Inset magnification, 2.5×. Scale bar, 100 µm. (F) Quantification of embryos in E. Ratio of embryos at different stages is plotted. Total number of embryos is above each bar. (N.S.) Not significant, (****) P < 0.0001; two-sided proportion test. (G) Images of embryos flushed from Eif4e1b^Het and Eif4e1b^KO female reproductive tracts at E3.5 after successful in vivo mating. Inset magnification, 2.5×. Scale bar, 100 µm.