Established Preblastocyst- and Blastocyst-Derived ES Cell Lines Have Highly Similar Gene Expression Profiles, Despite Their Differing Requirements for Derivation Culture Conditions

Abstract

The efficiency of embryonic stem (ES) cell derivation relies on an optimized culture medium and techniques for treating preimplantation stage embryos. Recently, ES cell derivation from the preblastocyst developmental stage was reported by removing the zona pellucida from embryos of the most efficient strain for ES cell derivation (129Sv) during early preimplantation. Here, we showed that ES cells can be efficiently derived and maintained in a modified medium (MEMa), from preblastocysts of a low-efficiency mouse strain (a hybrid consisting of 50% B6, 25% CBA, and 25% DBA). Preblastocyst-derived ES cell lines were normal in terms of pluripotency-related protein expression, and chromosome number. Also, preblastocyst-derived ES cell lines from various culture conditions showed pluripotency in vivo through teratoma analysis. Interestingly, ES cell lines produced from preblastocysts and blastocysts, regardless of the derivation culture conditions, are nearly indistinguishable by their global gene expression profiles.

Totipotency: What It Is and What It Is Not

“…Similarly, there have been no reports of generating embryos from a combination of mES and trophoblast stem cells [84]. The failure of aggregated stem cell lines derived thus far to spontaneously form embryos is likely to reflect the fact that stem cell lines have a range of properties [85][86][87] that are not identical either to zygotes [88,89] or to cells that have been freshly isolated from embryos [43][44][45][46][47]. While these negative findings do not strictly rule out the possibility that later-stage blastomeres or pluripotent stem cells ''could'' combine in some way to generate an embryo (it is logically impossible to prove something from a negative finding), they strongly suggest that collective reconstitution of an embryo from cells of a reaggregated morula-stage embryo (Fig.…”

“…However, there is no scientific evidence to date that twinning at the blastocyst stage involves totipotent cells, and multiple studies have concluded exactly the opposite; that is, that blastocyst cells are quite unlike totipotent zygotes on multiple parameters [43][44][45][46][47][85][86][87] and that blastocyst cells are completely incapable of producing a whole embryo when isolated from each other [145][146][147], instead producing only stem cell lines. These observations argue strongly that twinning does not involve totipotent cells, but rather relies on some other developmental mechanism.…”