background new research proposes the pluripotency of spermatogonial cells obtained from testis. these spermatogonia-derived stem cells are called embryonic stem-like cells that express embryonic stem cell markers and differentiate to the three germ layers. objectives the aim of the present study was to generate embryonic stem-like cells from neonatal mouse testis. materials and methods the test...

Reprogramming of a somatic nucleus to an induced pluripotent state can be achieved in vitro through ectopic expression of Oct4 (Pou5f1), Sox2, Klf4 and c-Myc. While the ability of these factors to regulate transcription in a pluripotent context has been studied extensively, their ability to interact with and remodel a somatic genome remains underexplored. Several recent studies have begun to pr...

How various epigenetic mechanisms restrict chromatin plasticity to determine the stability of repressed genes is poorly understood. Nuclear transfer to Xenopus oocytes induces the transcriptional reactivation of previously silenced genes. Recent work suggests that it can be used to analyze the epigenetic stability of repressed states. The notion that the epigenetic state of genes is an importan...

It has long been discovered that human pluripotent cells could be isolated from the blastocyst state of embryos and called human embryonic stem cells (ESCs). These cells can be adapted and propagated indefinitely in culture in an undifferentiated manner as well as differentiated into cell representing the three major germ layers: endoderm, mesoderm, and ectoderm. However, the derivation of huma...

In this issue of Cell, Takahashi et al. (2007) transfer their seminal work on somatic cell reprogramming from the mouse to human. By overexpressing the transcription factor quartet of Oct4, Sox2, Klf4, and c-Myc in adult human fibroblasts, they successfully isolate human pluripotent stem cells that resemble human embryonic stem cells by all measured criteria. This is a significant turning point...

Reprogramming of somatic cells to different extents has been reported using different methods. However, this is normally accompanied by the use of exogenous materials, and the overall reprogramming efficiency has been low. Chemicals and small molecules have been used to improve the reprogramming process during somatic cell nuclear transfer (SCNT) and induced pluripotent stem (iPS) cell generati...

DNA methylation reprogramming plays important roles in mammalian embryogenesis. Mammalian somatic cell nuclear transfer (SCNT) embryos with reprogramming defects fail to develop. Thus, we compared DNA methylation reprogramming in preimplantation embryos from bovine SCNT and in vitro fertilization (IVF) and analyzed the influence of vitamin C (VC) on the reprogramming of DNA methylation. The res...

The specific molecular mechanisms involved in somatic reprogramming remain unidentified. Removal of the oocyte genome is one of the primary causes of developmental failure in cloned embryos, whereas intact oocyte shows stronger reprogramming capability than enucleated oocyte. To identify the reason for the low efficiency of cloning and elucidate the mechanisms involved in somatic reprogramming ...

a:4:{s:10:"Background";s:1707:"Early embryonic development in mammals begins in transcriptional silence with an oocyte-mediated transcriptional reprogramming of parental gametes occurs during a so called across-the-board process of “erase-and-rebuild”. In this process, the parental transcription programs are erased long before (maternal) or soon thereafter (paternal) fertilization to generate a...

objective: induced pluripotent stem cells are generated from somatic cells by direct reprogramming. these reprogrammed pluripotent cells have different applications in biomedical fields such as regenerative medicine. although viral vectors are widely used for efficient reprogramming, they have limited applications in the clinic due to the risk for immunogenicity and insertional mutagenesis. acc...