Cellular differentiation is the process in which a stem cell changes from one type to a differentiated one. Usually, the cell changes to a more specialized type. Differentiation happens multiple times during the development of a multicellular organism as it changes from a simple zygote to a complex system of tissues and cell types. Differentiation continues in adulthood as adult stem cells divide and create fully differentiated daughter cells during tissue repair and during normal cell turnover. Some differentiation occurs in response to antigen exposure. Differentiation dramatically changes a cell's size, shape, membrane potential, metabolic activity, and responsiveness to signals. These changes are largely due to highly controlled modifications in gene expression and are the study of epigenetics. With a few exceptions, cellular differentiation almost never involves a change in the DNA sequence itself. Metabolic composition, however, gets dramatically altered where stem cells are characterized by abundant metabolites with highly unsaturated structures whose levels decrease upon differentiation. Thus, different cells can have very different physical characteristics despite having the same genome.
Blastulation is the stage in early animal embryonic development that produces the blastula. In mammalian development, the blastula develops into the blastocyst with a differentiated inner cell mass and an outer trophectoderm. The blastula is a hollow sphere of cells known as blastomeres surrounding an inner fluid-filled cavity called the blastocoel. Embryonic development begins with a sperm fertilizing an egg cell to become a zygote, which undergoes many cleavages to develop into a ball of cells called a morula. Only when the blastocoel is formed does the early embryo become a blastula. The blastula precedes the formation of the gastrula in which the germ layers of the embryo form.
Oct-4, also known as POU5F1, is a protein that in humans is encoded by the POU5F1 gene. Oct-4 is a homeodomain transcription factor of the POU family. It is critically involved in the self-renewal of undifferentiated embryonic stem cells. As such, it is frequently used as a marker for undifferentiated cells. Oct-4 expression must be closely regulated; too much or too little will cause differentiation of the cells.
Sir Martin John EvansFLSW is an English biologist who, with Matthew Kaufman, was the first to culture mice embryonic stem cells and cultivate them in a laboratory in 1981. He is also known, along with Mario Capecchi and Oliver Smithies, for his work in the development of the knockout mouse and the related technology of gene targeting, a method of using embryonic stem cells to create specific gene modifications in mice. In 2007, the three shared the Nobel Prize in Physiology or Medicine in recognition of their discovery and contribution to the efforts to develop new treatments for illnesses in humans.
In developmental biology, the cells that give rise to the gametes are often set aside during embryonic cleavage. During development, these cells will differentiate into primordial germ cells, migrate to the location of the gonad, and form the germline of the animal.
SRY -box 2, also known as SOX2, is a transcription factor that is essential for maintaining self-renewal, or pluripotency, of undifferentiated embryonic stem cells. Sox2 has a critical role in maintenance of embryonic and neural stem cells.
Shinya Yamanaka is a Japanese stem cell researcher and a Nobel Prize laureate. He is a professor and the director emeritus of Center for iPS Cell Research and Application, Kyoto University; as a senior investigator at the UCSF-affiliated Gladstone Institutes in San Francisco, California; and as a professor of anatomy at University of California, San Francisco (UCSF). Yamanaka is also a past president of the International Society for Stem Cell Research (ISSCR).
Homeobox protein CDX-1 is a protein in humans that is encoded by the CDX1 gene. CDX-1 is expressed in the developing endoderm and its expression persists in the intestine throughout adulthood. CDX-1 protein expression varies along the intestine, with high expression in intestinal crypts and diminishing expression along intestinal villi.
Nodal homolog is a secretory protein that in humans is encoded by the NODAL gene which is located on chromosome 10q22.1. It belongs to the transforming growth factor beta superfamily. Like many other members of this superfamily it is involved in cell differentiation in early embryogenesis, playing a key role in signal transfer from the primitive node, in the anterior primitive streak, to lateral plate mesoderm (LPM).
Chromodomain-helicase-DNA-binding protein 8 is an enzyme that in humans is encoded by the CHD8 gene.
Sally Temple is an American developmental neuroscientist in Albany, New York. She is a co-founder and scientific director for The Neural Stem Cell Institute and is a professor of Neuroscience and Neuropharmacology at Albany Medical College Temple is also the principal investigator in her laboratory that focuses on neural stem cells and therapies for neurological-related disorders
Tsix is a non-coding RNA gene that is antisense to the Xist RNA. Tsix binds Xist during X chromosome inactivation. The name Tsix comes from the reverse of Xist, which stands for X-inactive specific transcript.
Elizabeth Jane Robertson is a British developmental biologist based at the Sir William Dunn School of Pathology, University of Oxford. She is Professor of Developmental Biology at Oxford and a Wellcome Trust Principal Research Fellow. She is best known for her pioneering work in developmental genetics, showing that genetic mutations could be introduced into the mouse germ line by using genetically altered embryonic stem cells. This discovery opened up a major field of experimentation for biologists and clinicians.
X chromosome inactivation (XCI) is the phenomenon that has been selected during the evolution to balance X-linked gene dosage between XX females and XY males.
Magdalena Żernicka-Goetz is a Polish-British developmental biologist. She is Professor of Mammalian Development and Stem Cell Biology in the Department of Physiology, Development and Neuroscience and Fellow of Sidney Sussex College, Cambridge. She also serves as Bren Professor of Biology and Biological Engineering at California Institute of Technology (Caltech).
Haifan Lin is a Chinese-born American stem cell biologist. He is the Eugene Higgins Chair Professor of Cell Biology at Yale University and the founding Director of the Yale Stem Cell Center. He previously founded and directed the Stem Cell Research Program at Duke University. Recognized for his significant contributions to stem cell research, he was elected to the US National Academy of Sciences and American Academy of Arts and Sciences in 2018.
Emily Bernstein is a professor at Mount Sinai School of Medicine known for her research on RNA interference, epigenetics, and cancer, especially melanoma.
X chromosome reactivation (XCR) is the process by which the inactive X chromosome (the Xi) is re-activated in the cells of eutherian female mammals. Therian female mammalian cells have two X chromosomes, while males have only one, requiring X-chromosome inactivation (XCI) for sex-chromosome dosage compensation. In eutherians, XCI is the random inactivation of one of the X chromosomes, silencing its expression. Much of the scientific knowledge currently known about XCR comes from research limited to mouse models or stem cells.
François Guillemot,, is a French neurobiologist, currently working at the Francis Crick Institute in London. His research focuses on the behaviour of neural stem cells in embryos and adult brains.
Nissim Benvenisty is Professor of Genetics, the Herbert Cohn Chair in Cancer Research and the Director of “The Azrieli Center for Stem Cells and Genetic Research” at the Alexander Silberman Institute of Life Sciences, Hebrew University.
