Abbreviations: Ad: adenovirus, bFGF: basic fibroblast growth factor, BMP: bone morphogenetic protein, CNS: central nervous system, ES: embryonic stem, FACS: fluorescence activated cell sorting, HIV: human immunodeficiency virus, ICM: inner cell mass, LIF: leukemia inhibitory factor, MEF: mouse embryonic fibroblast, RNAi: RNA interference, SCNT: somatic cell nucleus transfer, UTR: untranslated r...

Fibroblast growth factor (FGF) signaling controls fundamental processes such as proliferation, differentiation and migration throughout mammalian development. Here we discuss recent discoveries that implicate FGF/Erk signaling in the control of pluripotency and lineage specification in several different stem cell states, including the separation of pluripotent epiblast and primitive endoderm in...

The breakneck speed of scientific developments in embryonic stem (ES) cell technologies is, commensurately, ushering forth new bioethical debate(s) regarding these cells. A framework of bioethical principles is presented here to guide biomedical scientists and others engaged in improving human welfare through the application of ES cell-based therapies.

Pax6 plays an important role in embryonic cell (ES) differentiation during embryonic development. Expression of Pax6 undergoes from a low level to high levels following ES cell differentiation to neural stem cells, and then fades away in most of the differentiated cell types. There is a limited knowledge concerning how Pax6 is regulated in ES cell differentiation. We report that Pax6 expression...

The c-Jun NH(2)-terminal kinase (JNK) is implicated in proliferation. Mice with a deficiency of either the Jnk1 or the Jnk2 genes are viable, but a compound deficiency of both Jnk1 and Jnk2 causes early embryonic lethality. Studies using conditional gene ablation and chemical genetic approaches demonstrate that the combined loss of JNK1 and JNK2 protein kinase function results in rapid senescen...

The rat is one of the most commonly used laboratory animals in biomedical research and the recent isolation of genuine pluripotent rat embryonic stem (ES) cell lines has provided new opportunities for applying contemporary genetic engineering techniques to the rat and enhancing the use of this rodent in scientific research. Technical refinements that improve the stability of the rat ES cell cul...

MicroRNAs have been implicated as regulators of embryonic stem (ES) cell self-renewal and pluripotency. In this issue, Xu et al. (2009) demonstrate that miR-145 facilitates ES cell differentiation by repressing the core pluripotency factors OCT4, SOX2, and KLF4, thereby silencing the self-renewal program.

MATERIALS Reagents AmpliTaq polymerase (Perkin Elmer) Bovine serum albumin (BSA) (nuclease-free; Boehringer Mannheim; stock 1.6 mg/ml) Dimethyl sulfoxide (DMSO) (Aldrich) DNA in ES PCR Lysis buffer (include positive and negative controls) dNTPs (Pharmacia; stock of the mix 10 mM) ES colonies in G418 selection (see Electroporating DNA into Embryonic Stem (ES) Cells and Selection) Light mineral o...

Pluripotent human stem cells isolated from early embryos represent a potentially unlimited source of many different cell types for cell-based gene and tissue therapies [1-3]. Nevertheless, if the full potential of cell lines derived from donor embryos is to be realised, the problem of donor-recipient tissue matching needs to be overcome. One approach, which avoids the problem of transplant reje...