Researchers find gene to explain mouse embryonic stem cell immortality

Mar 24, 2010

Researchers at the National Institute on Aging (NIA), part of the National Institutes of Health, have discovered a key to embryonic stem (ES) cell rejuvenation in a gene -- Zscan4 -- as reported in the March 24, 2010, online issue of Nature. This breakthrough finding could have major implications for aging research, stem cell biology, regenerative medicine and cancer biology.

ES cells are unique because, along with the ability to develop into nearly any type of cell in the body, they can produce infinite generations of new, fully operational ES cells (daughter cells). ES cells are essentially immortal, meaning that they can divide indefinitely to produce additional generations of functional ES daughter cells.

Other cells can only produce a certain number of generations of daughter cells before they no longer function properly. This is partially because the telomere, the protective end of the chromosome which carries the cell's , shortens each time a cell divides. When a telomere becomes too short, it can no longer protect the cell. At that time, the cell dies, turns itself off, known as cell senescence, or produces abnormal and possibly dysfunctional cells.

Until now, the mechanism for the ES cell's immortality had been a mystery. The prevailing theory was that ES cells practiced "self-renewal," meaning that when they divided, they produced daughter cells that were completely unaltered (including telomere length) from the parent. NIA researchers discovered that the process occurring in ES cells can be more appropriately described as "rejuvenation" than the "self-renewal." As in other cells, when ES cells replicate, the are not identical to the parent and the telomeres are shorter.

However, ES cells express a unique Zscan4 gene that, when activated (or turned on), rejuvenates the ES cell, restoring it to its original vigor. This rejuvenation includes telomere lengthening through recombination, when a shorter telomere combines with a longer telomere to elongate itself. Zscan4 then turns off. The gene is not turned on every time that the cell replicates—approximately 5 percent of the cells will have an activated gene at any one point. The process is a cycle of cell replication (with shortening) and intermittent activation of Zscan4 (cell rejuvenation).

Researchers are currently investigating whether a similar mechanism also operates in human cells.

Explore further: Students use physics to unpack DNA, one molecule at a time

More information: "Zscan4 regulates telomere elongation and genomic stability in ES cells" by Michal Zalzman, Geppino Falco, Lioudmila V. Sharova, Akira Nishiyama, Marshall Thomas, Sung-Lim Lee, Carole A. Stagg, Hien G. Hoang, Hsih-Te Yang, Fred E. Indig, Robert P. Wersto, and Minoru S. H. Ko. Nature. March 24, 2010. DOI:10.1038/nature08882

Provided by National Institutes of Health

5 /5 (8 votes)

Related Stories

Unpacking condensins' function in embryonic stem cells

Feb 22, 2010

Regulatory proteins common to all eukaryotic cells can have additional, unique functions in embryonic stem (ES) cells, according to a study in the February 22 issue of the Journal of Cell Biology. If cancer ...

Human ES cells progress slowly in myelin's direction

Apr 09, 2009

Scientists from the University of Wisconsin, USA, report in the journal Development the successful generation from human embryonic stem cells of a type of cell that can make myelin, a finding that opens up new possibilities for bo ...

Recommended for you

Atomic structure of key muscle component revealed

just added

Actin is the most abundant protein in the body, and when you look more closely at its fundamental role in life, it's easy to see why. It is the basis of most movement in the body, and all cells and components ...

Brand new technology detects probiotic organisms in food

Jul 23, 2014

In the food industr, ity is very important to ensure the quality and safety of products consumed by the population to improve their properties and reduce foodborne illness. Therefore, a team of Mexican researchers ...

Protein evolution follows a modular principle

Jul 23, 2014

Proteins impart shape and stability to cells, drive metabolic processes and transmit signals. To perform these manifold tasks, they fold into complex three-dimensional shapes. Scientists at the Max Planck ...

Report on viruses looks beyond disease

Jul 22, 2014

In contrast to their negative reputation as disease causing agents, some viruses can perform crucial biological and evolutionary functions that help to shape the world we live in today, according to a new report by the American ...

User comments : 3

Adjust slider to filter visible comments by rank

Display comments: newest first

fourthrocker
4.5 / 5 (2) Mar 24, 2010
I can taste the elixar of immortality already, my brain is swelling with anticipation.
Merrill
not rated yet Mar 25, 2010
Can this gene be turned on for IPS cells? If so, you have discovered the fountain of youth?
ancible
not rated yet Mar 25, 2010
@fourthrocker

Haha, poetic. I always get that feeling for a minute after reading these types of articles. I actually think I might be addicted to the thrill and use it in place of morning coffee.