Navigation Links
Putting microRNAs on the stem cell map
Date:8/7/2008

CAMBRIDGE, Mass. (August 7, 2008) Embryonic stem cells are always facing a choiceeither to self-renew or begin morphing into another type of cell altogether.

It's a tricky choice, governed by complex gene regulatory circuitry driven by a handful of key regulators known as "master transcription factors," proteins that switch gene expression on or off.

In the past few years, scientists in the lab of Whitehead Member Richard Young and their colleagues have mapped out key parts of this regulatory circuitry, but the genes that produce the tiny snippets of RNA known as microRNAs have until now been a missing piece of the map. Since microRNAs are a second set of regulators that help to instruct stem cells whether to stay in that state, they play key roles in development.

Young and colleagues have now discovered how microRNAs fit into the map of embryonic stem cell circuitry. With this map, the scientists have moved one step closer to understanding how adult cells can be reprogrammed to an embryonic state and then to other types of cells, and to understanding the role of microRNAs in cancer and other diseases.

"By understanding how master transcription factors turn microRNAs on and off, we now see how these two groups of gene regulators work together to control the state of the cell," says Young, senior author on the study reported in the August 8 issue of Cell. "MicroRNAs are a special class of molecules because they not only contribute to cellular control but they play important roles in disease states such as cancer."

Previous studies had shown that the microRNA machinery is important in maintaining embryonic stem cells in their embryonic state, but offered only partial views of how microRNA genes fit in with the overall gene regulation circuitry. To do so required mapping the sites in the genome from which microRNA genes start, explains Stuart Levine, co-lead author on the paper and postdoctoral scientist in Young's lab.

"Knowing where genes start is essential to understanding their control," says Levine. "Based on our knowledge of microRNA gene start sites we were able to discover how these genes are controlled by the master transcription factors."

The researchers first created genome-wide maps of human and mouse embryonic stem cells that pinpoint where transcription factors bind to DNA and launch gene expression. This pinpointed where four master transcription factors (known as Oct4, Sox2, Nanog and Tcf3) were occupying sites where microRNA genes start to be transcribed. They found that the four core transcription factors are interacting with two key sets of microRNA genes. One set of microRNA genes is actively expressed in embryonic stem cells. The other set is silenced in those cells by other gene regulatory proteins known as Polycomb proteins. These proteins repress genes that are key for later development, a role previously described by Young lab researchers and their colleagues.

"We now have a list of what microRNAs are important in embryonic stem cells," says Alex Marson, co-lead author on the paper and an MD/PhD student in the Young lab. "This gives us clues of which microRNAs you might want to target to direct an embryonic stem cell into another type of cell. For example, you might be able to harness a microRNA to help drive an embryonic stem cell to become a neuron, aiding with neurodegenerative disease or spinal cord injury."

Moreover, the results give scientists a better platform for analyzing microRNA gene expression in cancer and other diseases. "We and others are finding that the overall gene circuitry for embryonic stem cells and cancer cells is very similar," notes Marson. "Now that we have connected the circuitry to microRNAs, we can begin to compare microRNAs that are regulated in embryonic stem cells to those in cancer cells."


'/>"/>

Contact: Cristin Carr
carr@wi.mit.edu
617-324-0460
Whitehead Institute for Biomedical Research
Source:Eurekalert

Related medicine news :

1. When it comes to putting, Tiger and Nicklaus might not have best advice
2. When it comes to putting, Tiger and Nicklaus
3. Putting Health Before Politics: How the United States Senate Can Fix Global HIV/AIDS Funding
4. Targeting aggressive breast cancers by putting them to sleep
5. VA Putting Mobile Pharmacies on the Road
6. U.S. Soccer Team Putting Vision in Focus for the Beijing 2008 Olympic Games
7. Putting an End to Medical Cruelty: A Horrifying Article in Yahoo this Week by T. L. Kittle
8. Putting the Medical Profession on Notice!: Widow Tells Tragic Story of How Her Husband Died Due to Misdiagnosis and Mistreatment
9. Putting on Pedometer Helps Walkers Shed Pounds
10. Putting risk in perspective: Do people make better decisions when they understand average risk?
11. AUDIO from Medialink and P&G: Putting Your Smile in Hollywoods Spotlight
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:5/26/2016)... ... ... MadgeTech will be showcasing its line of data logging products , ... MadgeTech headquarters. With products sold in more than 100 countries around the world, MadgeTech ... , In 2012, NASA strategically set up 17 RHTemp101A MadgeTech data loggers around ...
(Date:5/26/2016)... ... May 26, 2016 , ... An April Gallup survey found rising health care ... of Sun Health Senior Living (SHSL) may not share those same worries ... prescription copays for the year, while holding the line on increasing their contributions, including ...
(Date:5/26/2016)... ... May 26, 2016 , ... Leadership of ... today announced the organization has earned its ISO 13485 certification, indicating the company’s ... with all rules and policies associated with ISO quality standard 13485. , ...
(Date:5/26/2016)... ... 2016 , ... North Cypress Medical Center hosted its 9th Annual ... With the help of community partners, the event organizers raised $45,000 for the ... service members and their families through health, wellness, and therapeutic support. , A ...
(Date:5/26/2016)... FL (PRWEB) , ... May 26, 2016 , ... The ... of events featuring guest speaker Dr. Adonis Maiquez MD, ABAARM. Dr. Adonis , ... and Regenerative Medicine, and a member of the Institute for Functional Medicine. , He ...
Breaking Medicine News(10 mins):
(Date:5/25/2016)... 25, 2016 Digital Health Dialog, LLC ... by the US Patent and Trademark Office of ... proprietary processes for electronic opt-­in and processing of ... programs, HIPAA compliance and otherwise. Logo - ... "Our technology allows for individuals to ...
(Date:5/24/2016)... 24, 2016 Niederländische Chirurgen ... die es Ärzten erlaubt, ihre Expertise weltweit zu ... kombiniert Live Streaming mit einer Instant-Messaging-Funktion und der ... Mediziner in Europa, Afrika, Asien und den ... die Plattform registriert. Information und Weiterbildung   ...
(Date:5/24/2016)... May 24, 2016  Diana Russell suffers from a ... from the inside out.  This disease has put her ... her children and grandchildren to leave her home.  Because ... family cannot haul the wheelchair.  So if there is ... and Diana is left to wait for the bus. ...
Breaking Medicine Technology: