REV1 and abortion: Bearing the above in mind, we propose that blocking the incorporation of erythritol-derived erythrose-4-phosphate into the central carbon metabolism of Rev1 by deleting the genes encoding the transaldolase (Tal) and the fructose-bisphosphate aldolase (Fba) may impair the ability of the vaccine to proliferate massively in the placenta, thereby preventing the induction of abortion in pregnant ewes [31].