Byrne JA, Pedersen DA, Clepper LL, et al. Producing primate embryonic stem cells by somatic cell nuclear transfer. Nature 2007;450:497-502
ABSTRACT Derivation of embryonic stem (ES) cells genetically identical to a patient by somatic cell nuclear transfer (SCNT) holds the potential to cure or alleviate the symptoms of many degenerative diseases while circumventing concerns regarding rejection by the host immune system. However, the concept has only been achieved in the mouse, whereas inefficient reprogramming and poor embryonic development characterizes the results obtained in primates. Here, we used a modified SCNT approach to produce rhesus macaque blastocysts from adult skin fibroblasts, and successfully isolated two ES cell lines from these embryos. DNA analysis confirmed that nuclear DNA was identical to donor somatic cells and that mitochondrial DNA originated from oocytes. Both cell lines exhibited normal ES cell morphology, expressed key stem-cell markers, were transcriptionally similar to control ES cells and differentiated into multiple cell types in vitro and in vivo. Our results represent successful nuclear reprogramming of adult somatic cells into pluripotent ES cells and demonstrate proof-of-concept for therapeutic cloning in primates.
- SourceAvailable from: Maria Krivega
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- "In rhesus monkey SCNT-ESC lines have been obtained (Byrne et al., 2007), but the live birth of cloned animals has not yet been reported. Compared with normal embryos, the ICM cells of cloned embryos maintain a high level of DNA methylation and this may disturb normal embryo development after SCNT (Yang et al., 2007). "
ABSTRACT: During human pre-implantation development the totipotent zygote divides and undergoes a number of changes that lead to the first lineage differentiation in the blastocyst displaying trophectoderm and inner cell mass on day 5. The trophectoderm is a differentiated epithelium needed for implantation and the inner cell mass (ICM) forms the embryo proper and serves as a source for pluripotent embryonic stem cells. The blastocyst implants around day 7. The second lineage differentiation occurs in the ICM after implantation resulting in specification of primitive endoderm and epiblast. Knowledge on human pre-implantation development is limited due to ethical and legal restrictions on embryo research and scarcity of materials. Studies in the human are mainly descriptive and lack functional evidence. Most information on embryo development is obtained from animal models and embryonic stem cell cultures and should be extrapolated with caution. This paper reviews totipotency and the molecular determinants and pathways involved in lineage segregation in the human embryo, as well as the role of embryonic genome activation, cell cycle features and epigenetic modifications.Molecular Human Reproduction 04/2014; DOI:10.1093/molehr/gau027 · 3.48 Impact Factor
Principles of Cloning, 2nd edited by Jose Cibelli, Ian Wilmut, Rudolf Jaenisch, John Gurdon, Robert Lanza, Michael West, Keith Campbell, 10/2013: chapter 37: pages 465-471; Elsevier.
- "Quantitative Analysis The most common comparison at the gene expression level is done by looking at the transcriptome of the cells and by comparing gene expression profiles. In niche (Byrne et al., 2007). Particularly, it is the existence of a functional hierarchy among signaling molecules, which contribute to either the initiation of large-scale phenotypic change or the maintenance of the current state. "
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- "The general value of polarized light microscopy for the biomedical sciences lies in the label-free imaging of structural parameters that can be followed real-time while cells and tissues are functioning under physiological conditions. One example of this is the use of the LC-PolScope technique to image the meiotic spindle in egg cells undergoing procedures for in-vitro fertilization and for cloning (Byrne et al. 2007; Keefe et al. 2003; Liu et al. 2000). In this article we review the use of the LC-PolScope for generating maps of birefringence measured in transparent specimens, and introduce a new use of the instrument, requiring a slight modification, to create maps of linear and circular diattenuation. "
ABSTRACT: Polarized light microscopy provides unique opportunities for analyzing the molecular order in man-made and natural materials, including biological structures inside living cells, tissues, and whole organisms. 20 years ago, the LC-PolScope was introduced as a modern version of the traditional polarizing microscope enhanced by liquid crystal devices for the control of polarization, and by electronic imaging and digital image processing for fast and comprehensive image acquisition and analysis. The LCPolScope is commonly used for birefringence imaging, analyzing the spatial and temporal variations of the differential phase delay in ordered and transparent materials. Here we describe an alternative use of the LC-PolScope for imaging the polarization dependent transmittance of dichroic materials. We explain the minor changes needed to convert the instrument between the two imaging modes, discuss the relationship between the quantities measured with either instrument, and touch on the physical connection between refractive index, birefringence, transmittance, diattenuation, and dichroism.Journal of optics 09/2013; 15(9). DOI:10.1088/2040-8978/15/9/094007 · 2.01 Impact Factor