Featured Research

from universities, journals, and other organizations

Researchers Discover Key To Human Embryonic Stem-cell Potential

Date:
September 11, 2005
Source:
Whitehead Institute for Biomedical Research
Summary:
Researchers at Whitehead Institute for Biomedical Research working with human embryonic stem cells have uncovered the process responsible for the single-most tantalizing characteristic of these cells: their ability to become just about any type of cell in the body, a trait known as pluripotency.

This Venn diagram represents how stem-cell master regulators Oct4, Nanog, and Sox2 work together in regulating the genome. It shows the number of genes that they interact with individually, in pairs, or as a triad.
Credit: Image courtesy of Whitehead Institute for Biomedical Research

What exactly makes a stem cell a stem cell? The question may seemsimplistic, but while we know a great deal of what stem cells can do,we don't yet understand the molecular processes that afford them suchunique attributes.

Related Articles


Now, researchers at Whitehead Institute for Biomedical Researchworking with human embryonic stem cells have uncovered the processresponsible for the single-most tantalizing characteristic of thesecells: their ability to become just about any type of cell in the body,a trait known as pluripotency.

"This is precisely what makes these stem cells so interestingfrom a therapeutic perspective," says Whitehead Member Richard Young,senior author on the paper which will be published September 8 in theearly online edition of the journal Cell. "They are wired so they canbecome almost any part of the body. We've uncovered a key part of thewiring diagram for these cells and can now see how this isaccomplished."

Once an embryo is a few days old, the stem cells start todifferentiate into particular tissue types, and pluripotency is foreverlost. But if stem cells are extracted, researches can keep them in thispluripotent state indefinitely, preserving them as a kind of cellularblank slate. The therapeutic goal then is to take these blank slatesand coax them into, say, liver or brain tissue. But in order to guidethem out of pluripotency with efficiency, we need to know what keepsthem there to begin with.

Researchers in the Whitehead laboratories of Young, RudolfJaenisch, MIT-computer scientist David Gifford, and the Harvard lab ofDouglas Melton focused on three proteins known to be essential for stemcells. These proteins, Oct4, Sox2, and Nanog, are called "transcriptionfactors," proteins whose job is to regulate gene expression.(Transcription factors are really the genome's primary movers,overseeing, coordinating, and controlling all gene activity.)

These proteins were known to play essential roles inmaintaining stem cell identity--if they are disabled, the stem cellimmediately begins to differentiate and is thus no longer a stem cell."But we did not know how these proteins instructed stem cells to bepluripotent," says Laurie Boyer, first author on the paper and apostdoctoral scientist who divides her time between the Jaenisch andYoung labs.

Using a microarray technology invented in the Young lab, Boyerand her colleagues analyzed the entire genome of a human embryonic stemcell and identified the genes regulated by these three transcriptionfactors. The research team discovered that while these transcriptionfactors activate certain genes essential for cell growth, they alsorepress a key set of genes needed for an embryo to develop.

This key set of repressed genes produce additionaltranscription factors that are responsible for activating entirenetworks of genes necessary for generating many different specializedcells and tissues. Thus, Oct4, Sox2, and Nanog are master regulators,silencing genes that are waiting to create the next generation ofcells. When Oct4, Sox2, and Nanog are inactivated as the embryo beginsto develop, these networks then come to life, and the stem cell ceasesto be a stem cell.

The new work provides the first wiring diagram of humanembryonic stem-cell regulatory circuitry. "This gives us a framework tofurther understand how human development is regulated," says Boyer.

"These findings provide the foundation for learning how tomodify the circuitry of embryonic stem cells to repair damaged ordiseased cells or to make cells for regenerative medicine," says Young."They also establish the foundation for solving circuitry for all humancells."

###

This research was funded by the National Human Genome ResearchInstitute and the National Institutes of Health. Richard Young consultsfor Agilent Technologies, manufacturers of his microarray platform.



Story Source:

The above story is based on materials provided by Whitehead Institute for Biomedical Research. Note: Materials may be edited for content and length.


Cite This Page:

Whitehead Institute for Biomedical Research. "Researchers Discover Key To Human Embryonic Stem-cell Potential." ScienceDaily. ScienceDaily, 11 September 2005. <www.sciencedaily.com/releases/2005/09/050911104655.htm>.
Whitehead Institute for Biomedical Research. (2005, September 11). Researchers Discover Key To Human Embryonic Stem-cell Potential. ScienceDaily. Retrieved November 24, 2014 from www.sciencedaily.com/releases/2005/09/050911104655.htm
Whitehead Institute for Biomedical Research. "Researchers Discover Key To Human Embryonic Stem-cell Potential." ScienceDaily. www.sciencedaily.com/releases/2005/09/050911104655.htm (accessed November 24, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Monday, November 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Are Female Bosses More Likely To Be Depressed?

Are Female Bosses More Likely To Be Depressed?

Newsy (Nov. 24, 2014) A new study links greater authority with increased depressive symptoms among women in the workplace. Video provided by Newsy
Powered by NewsLook.com
Winter Can Cause Depression — Here's How To Combat It

Winter Can Cause Depression — Here's How To Combat It

Newsy (Nov. 23, 2014) Millions of American suffer from seasonal depression every year. It can lead to adverse health effects, but there are ways to ease symptoms. Video provided by Newsy
Powered by NewsLook.com
Ebola-Hit Sierra Leone's Late Cocoa Leaves Bitter Taste

Ebola-Hit Sierra Leone's Late Cocoa Leaves Bitter Taste

AFP (Nov. 23, 2014) The arable district of Kenema in Sierra Leone -- at the centre of the Ebola outbreak in May -- has been under quarantine for three months as the cocoa harvest comes in. Duration: 01:32 Video provided by AFP
Powered by NewsLook.com
Don't Fall For Flu Shot Myths

Don't Fall For Flu Shot Myths

Newsy (Nov. 23, 2014) Misconceptions abound when it comes to your annual flu shot. Medical experts say most people older than 6 months should get the shot. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins