title: The epigenetics of early development: inferences from stem cells.
abstract: Approximately 200 cell types and multiple tissues are established throughout the development of the zygote to an adult mammal. During this process, the cellular genome remains fixed, yet the transcriptome of each of the cell types become widely divergent. This review discusses the epigenetics of preimplantation embryos and the use of embryonic stem cells (ESCs) and epiblast stem cells (EpiSCs) as cell-culture models for the inner cell mass (ICM) and epiblast, respectively. Differential patterns of transcription are set up during development by the action of key transcription factors and epigenetics, which are involved in the establishment and maintenance of stable transcriptional states during development. In early embryos, for example, changes in the epigenome consist of alterations to the methylation of CpG dinucleotides and post-translational modification of histones within chromatin. In addition, histone replacement occurs broadly in zygotes. The ICM of the blastocyst, on the other hand, has the amazing ability to contribute to every tissue and cell type present in the adult body. Therefore, ESCs are arguably the most important cell-culture model available to developmental biologists. The advantages and risks of using ESCs to model ICM pluripotency are therefore discussed.
authors.affiliation: Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut; University of Connecticut Stem Cell Institute, University of Connecticut, Storrs, Connecticut; Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut.
authors.forename: Theodore P
authors.initials: TP
authors.lastname: Rasmussen
mesh_terms: D000818:Animals; D053624:Blastocyst Inner Cell Mass; D019175:DNA Methylation; D044127:Epigenesis, Genetic; D006801:Humans; D051379:Mice; D008954:Models, Biological; D039904:Pluripotent Stem Cells; D057905:Stem Cell Research; D013234:Stem Cells