 |
|
Scientists discover stage at which an embryonic cell is fated to become a stem cell
January 11, 2007Findings have important implications for stem-cell research
Cambridge scientists have discovered the stage at which some of the cells of a fertilised mammalian egg are fated to develop into stem cells and why this occurs. The findings of the study, which overturn the long-held belief that cells are the same until the fourth cleavage (division) of the embryo, are reported in today's edition of Nature.
After fertilisation, the cells of the embryo at first undergo equal, symmetrical divisions and unequal, asymmetrical ones that direct smaller daughter cells towards the inside of the embryo. These become the inner cell mass of stem cells. Previously, it was believed that the mammalian embryo starts its development with identical cells and only as these inside and outside cells form do differences between cells first emerge.
However, research led by Professor Magdelena Zernicka-Goetz, University of Cambridge, has revealed evidence to suggest that differences between the embryonic cells are already apparent at the 4-cell-stage, before the cells become partitioned between the inside or outside of the embryo. And those differences depend on the orientation and order of the very first cleavage divisions of the embryo.
Professor Zernicka-Goetz said, "Our findings were surprising since they showed that cells of the mammalian embryo first start to differ from each other much earlier in development than previously supposed but also they give us a real clue on how to manipulate embryonic cells so that they will develop with the properties of the natural stem cells of the embryo."
The study also found cell fate and transcription activity is determined by the level of a methylated form of histone H3, one of the basic proteins around which DNA is packaged and which when modified in this way affects gene expression. They found that the higher the levels of this modified form of histone H3, the more predisposed the mammalian embryonic cells were to develop the qualities of inner embryonic cells, a population that have stem-cell-like properties. Thus, their results show that manipulating epigenetic information in this protein in early mouse embryos can influence cell fate determination.
University of Cambridge
However, research led by Professor Magdelena Zernicka-Goetz, University of Cambridge, has revealed evidence to suggest that differences between the embryonic cells are already apparent at the 4-cell-stage, before the cells become partitioned between the inside or outside of the embryo. And those differences depend on the orientation and order of the very first cleavage divisions of the embryo.
Professor Zernicka-Goetz said, "Our findings were surprising since they showed that cells of the mammalian embryo first start to differ from each other much earlier in development than previously supposed but also they give us a real clue on how to manipulate embryonic cells so that they will develop with the properties of the natural stem cells of the embryo."
The study also found cell fate and transcription activity is determined by the level of a methylated form of histone H3, one of the basic proteins around which DNA is packaged and which when modified in this way affects gene expression. They found that the higher the levels of this modified form of histone H3, the more predisposed the mammalian embryonic cells were to develop the qualities of inner embryonic cells, a population that have stem-cell-like properties. Thus, their results show that manipulating epigenetic information in this protein in early mouse embryos can influence cell fate determination.
University of Cambridge
Embryonic Cells Current Events and Embryonic Cells News RSSNIH-funded researchers transform embryonic stem cells into human germ cells
Researchers funded in part by the National Institutes of Health have discovered how to transform human embryonic stem cells into germ cells, the embryonic cells that ultimately give rise to sperm and eggs.
A major step in making better stem cells from adult tissue
October 15, 2009 A team led by scientists from The Scripps Research Institute has developed a method that dramatically improves the efficiency of creating stem cells from human adult tissue, without the use of embryonic cells.
Sea lamprey jettison one-fifth of their genome
Researchers have discovered that the sea lamprey, which emerged from jawless fish first appearing 500 million years ago, dramatically remodels its genome. Shortly after a fertilized lamprey egg divides into several cells, the growing embryo discards millions of units of its DNA.
Chromosomal problems affect nearly all human embryos
For the first time, scientists have shown that chromosomal abnormalities are present in more than 90% of IVF embryos, even those produced by young, fertile couples.
Caltech researchers help unlock the secrets of gene regulatory networks
A quartet of studies by researchers at the California Institute of Technology (Caltech) highlight a special feature on gene regulatory networks recently published in the Proceedings of the National Academy of Sciences (PNAS).
Large DNA stretches, not single genes, shut off as cells mature
Experiments at Johns Hopkins have found that the gradual maturing of embryonic cells into cells as varied as brain, liver and immune system cells is apparently due to the shut off of several genes at once rather than in individual smatterings as previous studies have implied.
Testes stem cell can change into other body tissues, Stanford/UCSF study shows
Scientists at the Stanford University School of Medicine and at UC-San Francisco have succeeded in isolating stem cells from human testes.
Harm-reduction cigarettes are more toxic than traditional cigarettes, UC Riverside study finds
Typically, tobacco companies market harm-reduction cigarettes as being safer than traditional "full-flavored" brands, leading many smokers to conclude that the use of harm-reduction brands lowers their exposure to toxicants.
Gene packaging tells story of cancer development
To decipher how cancer develops, Johns Hopkins Kimmel Cancer Center investigators say researchers must take a closer look at the packaging.
Making flies sick reveals new role for growth factors in immunity
A Salmonella infection is not a positive experience. However, by infecting the common laboratory fruit fly Drosophila melanogaster with a Salmonella strain known for causing humans intestinal grief, researchers in the School of Life Sciences at Arizona State University have shed light on some key cell regulatory processes - with broad implications for understanding embryonic development, immune function and congenital diseases in humans.
More Embryonic Cells Current Events and Embryonic Cells News Articles
 |
Human Embryonic Stem Cell Protocols (Methods in Molecular Biology) by Kursad Turksen (Editor) Despite political and ethical controversies surrounding the study of human embryonic stem (hES) cells, new freedoms in regard to using them for research has allowed interest to remain high in understanding the regulatory mechanisms of stem cell self-renewal, their differentiation along various lineages, and their potential use in regenerative medicine. In Human Embryonic Stem Cell Protocols, Second Edition, internationally respected researchers expand upon the popular first edition and describe in detail their most useful techniques for the molecular and cellular manipulation of these intriguing cells. This diverse collection of readily reproducible methods has been optimized for the derivation, characterization, and differentiation of hES cells, with special attention given to... |
 |
Dead Embryonic Cells (Reissue) Sepultura (Primary Contributor) |
 |
ABC News Nightline Henry's Story For every medical breakthrough, there are many more patients who undergo experimental treatment only to see it fail. But even though the treatment fails, the patient still plays an important role, and offers a generous gift to our overall understanding of science. Laurie Strongin and Allen Goldberg did not seek the role they played in medical research. They found themselves there unexpectedly in 1995 when their first born, Henry, was diagnosed with a rare and deadly disease called Fanconi Anemia. Immediately, they were thrust onto the frontlines of medical research. Before Henry was a toddler they found themselves in the middle of a debate that would soon grip the nation over embryonic tissue research. But for Laurie and Allen there was never a debate. Doctors told them that the best... |
 |
Dead Embryonic Cells by Sepultura |
 |
Human Embryonic Stem Cells: The Practical Handbook by Stephen Sullivan (Editor), Chad A Cowan (Editor), Kevin Eggan (Editor) With this valuable practical guide, three members of the Harvard Stem Cell Institute have compiled and edited the definite handbook for the exciting new field of human embryonic stem cell research. The editors have gathered protocols from scientists with extensive reputation and expertise, describing and comparing currently used techniques for the culture of human stem cells and discussing the strengths and weaknesses of the different approaches. Human Embryonic Stem Cells: The Practical Handbook contains the first centralised collection of methods used in human embryonic stem cell biology. The book covers the derivation of human stem cell lines, the obtaining of cells from human stem cell banks, the culturing and characterisation of the cells, and the differentiation of the... |
 |
Human Stem Cell Manual: A Laboratory Guide by Jeanne F. Loring (Editor), Robin L. Wesselschmidt (Editor), Philip H. Schwartz (Editor) Stem cells are self-replicating and undifferentiated, meaning their function is not yet cell, tissue, or organ-specific. Due to the unique nature of these cells, research into their biology and function holds great promise for therapeutic applications through replacement or repair of diseased and damaged cells. This reader-friendly manual provides a practical "hands on" guide to the culture of human embryonic and somatic stem cells. By presenting methods for embryonic and adult lines side-by-side, the authors lay out an elegant and unique path to understanding the science of stem cell practice. The authors begin with a broad-based introduction to the field, and also review legal and regulatory issues and patents. Each experimental strategy is presented with an historical introduction,... |
 |
The Human Embryonic Stem Cell Debate: Science, Ethics, and Public Policy (Basic Bioethics) by Suzanne Holland (Editor), Karen Lebacqz (Editor), Laurie Zoloth (Editor) Human embryonic stem cells can divide indefinitely and have the potential to develop into many types of tissue. Research on these cells is essential to one of the most intriguing medical frontiers, regenerative medicine. It also raises a host of difficult ethical issues and has sparked great public interest and controversy. This book offers a foundation for thinking about the many issues involved in human embryonic stem cell research. It considers questions about the nature of human life, the limits of intervention into human cells and tissues, and the meaning of our corporeal existence. The fact that stem cells may be derived from living embryos that are destroyed in the process or from aborted fetuses ties the discussion of stem cell research to the ongoing debates on abortion. In... |
 |
The Stem Cell Divide: The Facts, the Fiction, and the Fear Driving the Greatest Scientific, Political, and Religious Debate of Our Time by Michael Bellomo (Author) There has been much recent debate about the merits, dangers, and nature of stem cell research. Some see in it the answer to every debilitating disease known to man, while others see it as a step away from human cloning. While the battle has raged, research is moving ahead, and California has already passed a measure that will give $3 billion in support to stem cell research. But as politics, religion, and the media weigh in on this complex issue, more and more of the scientific reality of stem cell research is getting lost. In the search for the truth about stem cell science, the author has interviewed the scientists whose cutting-edge research is at the very heart of this hot-button issue. The book explains what they have accomplished so far, what they're currently doing, and what... |
 |
Differentiation of Embryonic Stem Cells, Volume 365 (Methods in Enzymology) by Author Unknown (Author) This volume covers all aspects of embryonic stem cell differentiation, including mouse embryonic stem cells, mouse embryonic germ cells, monkey and human embryonic stem cells, and gene discovery. * Early commitment steps and generation of chimeric mice * Differentiation to mesoderm derivatives * Gene discovery by manipulation of mouse embryonic stem cells |
 |
Dead Embryonic Cells (Reissue) (Album Version) Sepultura (Primary Contributor) |
| © 2009 BrightSurf.com |