How embryonic stem cells develop into tissue-specific cells demonstrated

May 12, 2008

While it has long been known that embryonic stem cells have the ability to develop into any kind of tissue-specific cells, the exact mechanism as to how this occurs has heretofore not been demonstrated. Now, researchers at the Hebrew University of Jerusalem and elsewhere have succeeded in graphically revealing this process, resolving a long-standing question as to whether the stem cells achieve their development through selective activation or selective repression of genes.

The collaborative research group, which included 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 large proportions of their genome “promiscuously.” This permissive expression includes lineage-specific and tissue-specific genes, non-coding regions of the genome that are normally “silent,” and repetitive sequences in the genome, which comprise the majority of the mammalian genome but are also normally not expressed.

When ES cells differentiate into specific cell tissue-types, they undergo global genetic silencing. But until this occurs, the ES cells maintain an open and active genome. This might very well be the secret of their success, since by maintaining this flexibility they maintain their capacity to become any cell type. Once silencing, or genetic repression, occurs, this ability is gone.

Thus, one can say 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.


To reveal the process as to how this occurs, 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.

Hundreds of such microarrays were required in the study to cover the entire genome in different time points during stem cell differentiation. It was by observation of these sequences that the researchers were able to establish exactly how and at what point the stem cells developed into specific tissue cells and when the silencing occurs.

Source: The Hebrew University of Jerusalem

Explore further: Parasitic worm genomes: largest-ever dataset released

add to favorites email to friend print save as pdf

Related Stories

Scientists map mouse genome's 'mission control centers'

Nov 19, 2014

When the mouse and human genomes were catalogued more than 10 years ago, an international team of researchers set out to understand and compare the "mission control centers" found throughout the large stretches ...

Viral switches share a shape

Oct 27, 2014

A hinge in the RNA genome of the virus that causes hepatitis C works like a switch that can be flipped to prevent it from replicating in infected cells. Scientists have discovered that this shape is shared by several other ...

Recommended for you

Parasitic worm genomes: largest-ever dataset released

23 minutes ago

The largest collection of helminth genomic data ever assembled has been published in the new, open-access WormBase-ParaSite. Developed jointly by EMBL-EBI and the Wellcome Trust Sanger Institute, this new ...

Male sex organ distinguishes 30 millipede species

45 minutes ago

The unique shapes of male sex organs have helped describe thirty new millipede species from the Great Western Woodlands in the Goldfields, the largest area of relatively undisturbed Mediterranean climate ...

How can we avoid kelp beds turning into barren grounds?

4 hours ago

Urchins are marine invertebrates that mould the biological richness of marine grounds. However, an excessive proliferation of urchins may also have severe ecological consequences on marine grounds as they ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.