It is not fully clear why there is a higher contribution of pluripotent stem cells （PSCs） to the chimera produced by injection of PSCs into 4-cell or 8-cell stage embryos compared with blastocyst injection. Here, we...It is not fully clear why there is a higher contribution of pluripotent stem cells （PSCs） to the chimera produced by injection of PSCs into 4-cell or 8-cell stage embryos compared with blastocyst injection. Here, we show that not only embryonic stem cells （ESCs） but also induced pluripotent stem cells （iPSCs） can generate F0 nearly 100% donor cell-derived mice by 4-cell stage embryo injection, and the approach has a ＂dose effect＂. Through an analysis of the PSC-secreted proteins, Activin A was found to impede epiblast （EPI） lineage development while promoting trophectoderm （TE） differentiation, resulting in replacement of the EPI lineage of host embryos with PSCs. Interestingly, the injection of ESCs into blastocysts cultured with Activin A （cultured from 4-cell stage to early blastocyst at E3.5） could increase the contribution of ESCs to the chimera. The results indicated that PSCs secrete protein Activin A to improvetheir EPI competency after injection into recipient embryos through influencing the development of mouse early embryos. This result is useful for optimizing the chimera production system and for a deep understand- ing of PSCs effects on early embryo development.展开更多
Dear Editor,Targeted gene knock-out and knock-in mice are valuable tools for elucidating the function of genes in vivo （Capecchi, 2001）. Recently, the Cas9 endonuclease from Streptococcus pyogenes type Ⅱ CRISPR sys...Dear Editor,Targeted gene knock-out and knock-in mice are valuable tools for elucidating the function of genes in vivo （Capecchi, 2001）. Recently, the Cas9 endonuclease from Streptococcus pyogenes type Ⅱ CRISPR system has been demonstrated as a powerful tool for gene targeting.展开更多
基金This work was supported by The National Key Research and Development Program of China （2016YFA0100202）, National Nat- ural Science Foundation of China （Grant Nos. 31571497 and31601941 ）, Beijing Natural Science Foundation of China （6152004）, The National Thousand Talents Program of China and Research Programs from the State Key Laboratory for Agrobiotechnology, China Agricultural University （grant numbers 2015SKLAB1-4, 2017SKLAB1-2）.
文摘It is not fully clear why there is a higher contribution of pluripotent stem cells （PSCs） to the chimera produced by injection of PSCs into 4-cell or 8-cell stage embryos compared with blastocyst injection. Here, we show that not only embryonic stem cells （ESCs） but also induced pluripotent stem cells （iPSCs） can generate F0 nearly 100% donor cell-derived mice by 4-cell stage embryo injection, and the approach has a ＂dose effect＂. Through an analysis of the PSC-secreted proteins, Activin A was found to impede epiblast （EPI） lineage development while promoting trophectoderm （TE） differentiation, resulting in replacement of the EPI lineage of host embryos with PSCs. Interestingly, the injection of ESCs into blastocysts cultured with Activin A （cultured from 4-cell stage to early blastocyst at E3.5） could increase the contribution of ESCs to the chimera. The results indicated that PSCs secrete protein Activin A to improvetheir EPI competency after injection into recipient embryos through influencing the development of mouse early embryos. This result is useful for optimizing the chimera production system and for a deep understand- ing of PSCs effects on early embryo development.
文摘Dear Editor,Targeted gene knock-out and knock-in mice are valuable tools for elucidating the function of genes in vivo （Capecchi, 2001）. Recently, the Cas9 endonuclease from Streptococcus pyogenes type Ⅱ CRISPR system has been demonstrated as a powerful tool for gene targeting.
