Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers discover key to human embryonic stem-cell potential

09.09.2005


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



Now, 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 is precisely what makes these stem cells so interesting from a therapeutic perspective," says Whitehead Member Richard Young, senior author on the paper which will be published September 8 in the early online edition of the journal Cell. "They are wired so they can become almost any part of the body. We’ve uncovered a key part of the wiring diagram for these cells and can now see how this is accomplished."


Once an embryo is a few days old, the stem cells start to differentiate into particular tissue types, and pluripotency is forever lost. But if stem cells are extracted, researches can keep them in this pluripotent state indefinitely, preserving them as a kind of cellular blank slate. The therapeutic goal then is to take these blank slates and coax them into, say, liver or brain tissue. But in order to guide them out of pluripotency with efficiency, we need to know what keeps them there to begin with.

Researchers in the Whitehead laboratories of Young, Rudolf Jaenisch, MIT-computer scientist David Gifford, and the Harvard lab of Douglas Melton focused on three proteins known to be essential for stem cells. These proteins, Oct4, Sox2, and Nanog, are called "transcription factors," 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 in maintaining stem cell identity--if they are disabled, the stem cell immediately begins to differentiate and is thus no longer a stem cell. "But we did not know how these proteins instructed stem cells to be pluripotent," says Laurie Boyer, first author on the paper and a postdoctoral scientist who divides her time between the Jaenisch and Young labs.

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

This key set of repressed genes produce additional transcription factors that are responsible for activating entire networks of genes necessary for generating many different specialized cells and tissues. Thus, Oct4, Sox2, and Nanog are master regulators, silencing genes that are waiting to create the next generation of cells. When Oct4, Sox2, and Nanog are inactivated as the embryo begins to develop, these networks then come to life, and the stem cell ceases to be a stem cell.

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

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

David Cameron | EurekAlert!
Further information:
http://www.wi.mit.edu

More articles from Life Sciences:

nachricht Staying in Shape
16.08.2018 | Max-Planck-Institut für molekulare Zellbiologie und Genetik

nachricht Chips, light and coding moves the front line in beating bacteria
16.08.2018 | Okinawa Institute of Science and Technology (OIST) Graduate University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

Im Focus: The “TRiC” to folding actin

Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.

Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...

Im Focus: Lining up surprising behaviors of superconductor with one of the world's strongest magnets

Scientists have discovered that the electrical resistance of a copper-oxide compound depends on the magnetic field in a very unusual way -- a finding that could help direct the search for materials that can perfectly conduct electricity at room temperatur

What happens when really powerful magnets--capable of producing magnetic fields nearly two million times stronger than Earth's--are applied to materials that...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

2018 Work Research Conference

25.07.2018 | Event News

 
Latest News

Staying in Shape

16.08.2018 | Life Sciences

Diving robots find Antarctic seas exhale surprising amounts of carbon dioxide in winter

16.08.2018 | Earth Sciences

Protein droplets keep neurons at the ready and immune system in balance

16.08.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>