FBP knockout embryos die throughout the latter half of gestation. A–D: From E10.5 until birth there is continual attrition of Fubp1−/− embryos; relative distribution of viable KO (red), heterozygous (yellow), wild-type (blue) embryos at E9.5 to E11.5 (A), E13.5 to E14.5 (B), E17.5 to E20.5 (C), and perinatal (D) (note that with only a single exception all delivered KO embryos were stillborn, and that exception died within 15 minutes of birth). E: Graph of viability of FBP KO embryos versus developmental stage. E, embryonic day; FBP, far upstream element binding protein; KO, knockout.