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Stem Cells, Embryonic

Cell Biology

  1. Mahendra Rao

Published Online: 15 SEP 2006

DOI: 10.1002/3527600906.mcb.200400127

Reviews in Cell Biology and Molecular Medicine

Reviews in Cell Biology and Molecular Medicine

How to Cite

Rao, M. 2006. Stem Cells, Embryonic. Reviews in Cell Biology and Molecular Medicine. .

Author Information

  1. Stem Cell Unit, Laboratory of Neuroscience, National Institute on Aging, NIH, USA

Publication History

  1. Published Online: 15 SEP 2006

This is not the most recent version of the article. View current version (10 FEB 2013)


Embryonic development prior to implantation of the embryo in the uterus includes a stage of blastocyst formation, where the initial mass of cells is segregated into an inner cell mass destined to contribute to the developing embryo and an outer layer of cells that will contribute to the fetal portion of the placenta. Embryonic stem cells (ESCs) are cells derived from the inner cell mass of the developing preembryo that can be propagated indefinitely in culture. ESCs are characterized by the expression of a characteristic set of markers, the ability to self-renew indefinitely a lack of contact inhibition, atypical cell cycle regulation, the ability to form teratocarcinomas in nude mice, and the ability to differentiate into ectoderm, endoderm, and mesoderm either in vitro or in vivo after injection into blastocysts. This constellation of abilities distinguishes ESCs from all other cell populations, including adult stem cells.

The unique ability of ESCs to be propagated in culture, undergo genetic manipulation, and, nevertheless, retain the ability to contribute to all portions of the developing embryos, including germ cells, has been utilized to generate transgenic animals in which specific genes are introduced or removed. Such transgenic and knockouts have been utilized effectively to generate animal models of human disease, to develop improved strains, and to study critical aspects of development.

The ability to manipulate ESCs such that subsequent generations are derived solely from cultured manipulated cells, coupled with recent advances in deriving primate (including human) ESC lines has generated much excitement and hope as well as profound ethical concerns and considerable debate on how best to proceed.


  • Blastocyst;
  • Centrosome;
  • Chimera;
  • Cloning;
  • ES-like;
  • Gastrulation;
  • Homologous Recombination;
  • ICM;
  • IVF;
  • MAPC;
  • Morula;
  • Preembryo;
  • SCNT;
  • Self-renewal;
  • Stem Cells;
  • Teratocarcinomas;
  • Trophoectoderm