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During differentiation, stem cells change their gene expression profiles. Recent studies have implicated a role for nucleosome positioning and histone modifications during this process. [38] There are two components of this process: turning off the expression of embryonic stem cell (ESC) genes, and the activation of cell fate genes.
Stem cell division and differentiation A: stem cell; B: progenitor cell; C: differentiated cell; 1: symmetric stem cell division; 2: asymmetric stem cell division; 3: progenitor division; 4: terminal differentiation. Adult stem cells, also called somatic (from Greek σωματικóς, "of the body") stem cells, are stem cells which maintain ...
Embryonic stem cells exhibit dramatic and complex alterations to both global and site-specific chromatin structures. Lee et al. performed an experiment to determine the importance of deacetylation and acetylation for stem cell differentiation by looking at global acetylation and methylation levels at certain site-specific modification in histone sites H3K9 and H3K4.
Directed differentiation is a bioengineering methodology at the interface of stem cell biology, developmental biology and tissue engineering. [1] It is essentially harnessing the potential of stem cells by constraining their differentiation in vitro toward a specific cell type or tissue of interest. [ 2 ]
Clonal selection theory of lymphocytes: 1) A hematopoietic stem cell undergoes differentiation and genetic rearrangement to produce 2) immature lymphocytes with many different antigen receptors. Those that bind to 3) antigens from the body's own tissues are destroyed, while the rest mature into 4) inactive lymphocytes.
The process controls the organized spatial distribution of cells during the embryonic development of an organism. Morphogenesis can take place also in a mature organism, such as in the normal maintenance of tissue by stem cells or in regeneration of tissues after damage. Cancer is an example of highly abnormal and pathological tissue morphogenesis.
Multicellularity has evolved upwards of 25 times, [1] and due to this there is great possibility that multiple factors have shaped the differentiation of cells. There are three general types of cells: germ cells, somatic cells, and stem cells. Germ cells lead to the production of gametes, while somatic cells perform all other functions within ...
The purpose of the Stem Cell Lineage Database is to consolidate the three key components into a database that is accessible and capable of storing information "about cell type gene expression, cell lineage maps and stem cell differentiation protocols for both human and mouse stem cells and endogenous developmental lineages". [1]