In vitro development of t⁶/t⁶ embryos

Abstract

Embryos from matings in which approximately a third of the zygotes were expected to be t6/t6, a condition known to be lethal at the egg cylinder stage in vivo, were compared to normal control embryos during post-implantation culture. The percentage success of trophoblast outgrowths was the same in both groups while the experimental group showed a 25% deficiency of embryos with inner cell masses. Those experimental embryos which did have inner cell masses developed comparably to the control group and both groups showed roughly similar numbers of morphologically abnormal egg cylinders. Autoradiography disclosed no deficiency in 3H-thymidine and 3H-uridine labeling in disorganized egg cylinder embryos.

Targeted disruption of the even-skipped gene, evx1, causes early postimplantation lethality of the mouse conceptus.

“…5) distinguishes this mutant from all other classes of periimplantation mutants. The t ~ (Bennett 1975;GluecksohnSchoenheimer 1940) and f u g l (DeGregori et al 1994) mutants seem to be the closest to the e v x l -mutant in terms of timing and the high degree of disorganization within the egg cylinder, even though they do form twolayer egg cylinders with yolk sac cavities, and outgrowths of t6/t 6 blastocysts (an allele comparable to t~ Erickson and Pedersen 1975) (Soriano et al 1987) is also similar to the e v x lmutant in terms of timing, but the mutation has not been fully described. Unlike the e v x l -mutant, the survival of early implantation-defective mutants t w73 (Bennett 1975;Spiegelman et al 1976) and lethal yellow (AY; Eaton and Green 1963;Papaioannou and Gardner 1979;Michaud et al 1993) is determined by the degree of attachment between trophectoderm and maternal decidua, and well attached escapers form two-layer egg cylinders containing yolk sac and proamniotic cavities prior to degeneration.…”

Comparison of Implantation in Utero and in Vitro

“…Prolonged in vitro cultivation of blastocysts has been employed in studies of differentiation (Pedersen and Spindle, 1976;Wiley and Pedersen, 1978). Developmental problems of mice with mutations at the T locus (Erickson and Pedersen, 1975;Sherman and Wudl, 1977) and the agouti locus (Pedersen, 1974) have been studied with cultured embryos. The interaction with cells from different endometrial and nonendometrial sources has been studied using monolayers in vitro .…”