title: Transient pluripotent cell populations during primitive ectoderm formation: correlation of in vivo and in vitro pluripotent cell development.
abstract: Formation and differentiation of a pluripotent cell population is central to mammalian development, and the isolation, identification and manipulation of human pluripotent cells is predicted to be of therapeutic use. Within the early mammalian embryo, two distinct populations of pluripotent cells have been described: the inner cell mass (ICM), which differentiates to form a second pluripotent cell populations, the primitive ectoderm. Indirect evidence suggests the existence of temporally distinct intermediate pluripotent cell populations as primitive ectoderm is formed. We coupled an in vitro model of primitive ectoderm formation (the transition of embryonic stem cells to early primitive ectoderm-like (EPL) cells) with ddPCR-based techniques to identify three novel genes, Psc1, CRTR-1 and PRCE, that were expressed differently during pluripotent cell progression. Detailed mapping of these genes with Oct4, Rex1 and Fgf5 on pregastrulation embryos provided the first molecular evidence for the existence of successive, temporally distinct pluripotent cell populations in the embryo between the ICM and primitive ectoderm. No evidence was found for spatial heterogeneity within the Oct4(+) pool. The transition between populations correlated with morphological or developmental alterations in pluripotent cells in vivo. Genes that are temporally expressed during pluripotent cell progression may provide an opportunity for molecular discrimination of pluripotent cells at different stages of maturation in vivo and an understanding of the cellular origins and properties of pluripotent cell lines isolated from diverse sources. Furthermore, the strong correlation of gene expression demonstrated between EPL cell formation in vitro and primitive ectoderm formation in vivo validates EPL cells as a model for primitive ectoderm, thereby providing a model system for the investigation of pluripotent differentiation and an opportunity for directed differentiation of pluripotent cells to therapeutically useful cell populations.
authors.affiliation: Department of Molecular Biosciences, University of Adelaide, Adelaide 5005, South Australia.
authors.forename: T A
authors.initials: TA
authors.lastname: Pelton
authors.forename: S
authors.initials: S
authors.lastname: Sharma
authors.forename: T C
authors.initials: TC
authors.lastname: Schulz
authors.forename: J
authors.initials: J
authors.lastname: Rathjen
authors.forename: P D
authors.initials: PD
authors.lastname: Rathjen
mesh_terms: D000595:Amino Acid Sequence / Q000235:genetics; D000818:Animals; D001483:Base Sequence / Q000235:genetics; D019521:Body Patterning / Q000235:genetics*; D002454:Cell Differentiation / Q000235:genetics*; D019070:Cell Lineage / Q000235:genetics*; D002478:Cells, Cultured; D002874:Chromosome Mapping; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004475:Ectoderm / Q000166:cytology / Q000378:metabolism*; D004622:Embryo, Mammalian / Q000196:embryology / Q000378:metabolism*; D005260:Female; D051521:Fibroblast Growth Factor 5; D005346:Fibroblast Growth Factors / Q000235:genetics / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D050814:Octamer Transcription Factor-3; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism*; D014157:Transcription Factors
chemical_list: D004268:DNA-Binding Proteins; C496450:Fgf5 protein, mouse; D050814:Octamer Transcription Factor-3; C453240:PRCE protein, mouse; C494174:Pou5f1 protein, mouse; D011506:Proteins; D016601:RNA-Binding Proteins; C453239:Rbm27 protein, mouse; D012097:Repressor Proteins; C486070:Tfcp2l1 protein, mouse; D014157:Transcription Factors; D051521:Fibroblast Growth Factor 5; D005346:Fibroblast Growth Factors