Development of embryonic stem cells into tissue-specific cells
demonstrated
May 13th, 2008 - 3:52 pm ICT by admin - Email This Post
Washington May 13 (ANI): It was long known that embryonic stem cells
could develop into any kind of tissue-specific cells, but now
researchers have also uncovered the yet unknown mechanism behind this
process.
Researchers at the Hebrew University of Jerusalem have successfully
revealed this process graphically and provided the answer to the long-
standing question as to whether the stem cells achieve their
development through selective activation or selective repression of
genes.
The team of researchers including Dr. Eran Meshorer of the Department
of Genetics at the Silberman Institute of Life Sciences at the Hebrew
University of Jerusalem has revealed that the embryonic stem (ES)
cells express a major part of their genome promiscuously.
This liberal expression includes lineage-specific and tissue-specific
genes, non-coding regions of the genome that are normally silent, and
repetitive sequences in the genome, comprising the majority of the
mammalian genome but are also normally not expressed.
At the time of differentiation into specific cell tissue-types, ES
cells undergo global genetic silencing. But till this time, the ES
cells maintain an open and active genome. This may hold the key to
their success, as this flexibility allows them to maintain their
capacity to become any cell type. However, this ability is lost once
silencing, or genetic repression occurs.
This implies that the ES cells stand at the ready until the last
minute, prepared to engage in selective activation into specific
cells, holding in abeyance their ability to become any kind of cells
at the point and time required.
In order to reveal this process, the researchers created the first
full-mouse genomic platform of DNA microarrays. Microarrays are glass-
based chips that allow simultaneous detection of thousands of genes.
The microarrays used in the study were not confined to specific genes
only but spanned the entire genome.
The researchers required hundreds of such microarrays for this study
to cover the entire genome in different time points during stem cell
differentiation. And by observing these sequences they could
ascertain exactly how and at what point the stem cells developed into
specific tissue cells and when the silencing occurs. (ANI)
http://www.thaindia
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StemCells subscribers may also be interested in these sites:
Children's Neurobiological Solutions
http://www.CNSfoundation.org/
Cord Blood Registry
http://www.CordBlood.com/at.cgi?a=150123
The CNS Healing Group
http://groups.yahoo.com/group/CNS_Healing
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