Fig. 6.

Reduced Xist domains in extra-embryonic tissue of female embryos with a paternally inherited Xist^INV allele. RNA FISH on female embryos collected at E6.5 reveals Xist RNA (green) coating of the inactive X chromosome throughout the whole of the wild-type female embryo (left panel) and in the increased magnifications of the epiblast (epi) and ectoplacental cone (epc) (middle right panels). Xist RNA coating can be seen at levels comparable to wild type in the Xist^INV epiblast only (middle left and bottom right panels). In the extra-embryonic part of the embryo the domains appear smaller and weaker (middle left and top right panels).