Navigation Links
MicroRNA undermines tumor suppression
Date:3/17/2009

FINDINGS: Scientists at the Whitehead Institute for Biomedical Research and the National University of Singapore have discovered the first microRNA (miRNA) capable of directly tamping down the activity of the well known tumor-suppressor gene, p53, While p53 functions to prevent tumor formation, the p53 gene is thought to malfunction in more than 50% of cancerous tumors.

RELEVANCE: The study reports the first time a miRNA has been shown to directly affect the p53 protein level, although researchers have previously identified other genes and miRNAs that indirectly affect p53's activity.

CAMBRIDGE, Mass. (March 17, 2009) A small piece of RNA, or microRNA (miRNA), ratchets down the activity of the tumor-suppressor gene p53, according to a study by Whitehead Institute and National University of Singapore researchers.

While p53 functions to suppress tumor formation, the p53 gene is thought to malfunction in more than 50% of cancerous tumors.

The study published online March 17 in Genes and Development reports the first time that a miRNA has been shown to directly affect the p53 gene, although researchers have previously identified other genes and miRNAs that regulate p53's activity indirectly.

"For critical genes like p53, it's important that they are maintained at the right level in the cell," says Beiyan Zhou, a postdoctoral researcher in the lab of Whitehead Member Harvey Lodish and mentor to the paper's first author, Minh Le. "Le's work describes one more layer of regulatory mechanism that balances p53 gene expression."

miRNAs, short snippets of RNA, usually reduce how often a certain gene is translated into a protein. When a miRNA matches with and binds to a given messenger RNA coding for a specific protein, thereby preventing that messenger RNA from acting as a template for protein creation.

To investigate whether any miRNAs directly affect p53, Le, who is a joint graduate student in Lodish's lab and in the lab of Bing Lim at the National University of Singapore, searched the p53 gene for any sites that matched with known miRNAs from two databases. Only miRNA125b potentially has p53 target sites in humans, in zebrafish, and in many other vertebrates, indicating that it was important enough in cellular processes to be conserved through evolution.

Le tested miRNA125b's effects on several types of cells known to express p53, including human neural and lung cells. When Le reduced the amount of miRNA125b in the cells, p53 levels and the number of cells undergoing apoptosis (a type of programmed cell death that can be triggered by p53) both increased, whereas an increase in miRNA125b levels decreased levels of p53 and the number of apoptotic cells.

To confirm that miRNA125b played a similar role in developing organisms, Le changed the miRNA125b levels in zebrafish embryos. When she reduced miRNA125b levels in the embryos, cellular p53 levels and apoptosis both increased.

"Taking all of this data together, the p53 pathway is a major target of miRNA125b," says Lodish, who is also a professor of biology and bioengineering at MIT. "Most miRNAs have multiple targets, but there are a few cases that a miRNA has one major target and this is one of them."


'/>"/>

Contact: Nicole Giese
giese@wi.mit.edu
617-258-6851
Whitehead Institute for Biomedical Research
Source:Eurekalert

Related medicine news :

1. MicroRNAs make for safer cancer treatments
2. Gladstone scientists identify single microRNA that controls blood vessel development
3. Putting microRNAs on the stem cell map
4. Need microRNA processing? Get Smad
5. MicroRNA controls expression of oncogenes
6. MicroRNAs appear essential for retinal health
7. MicroRNAs, EMT and cancer progression
8. Replacing absent microRNAs could make tumors less invasive, more treatable
9. Single microRNA fine-tunes innate immune response
10. MicroRNAs May Predict Colon Cancer Prognosis
11. 2 microRNAs promote spread of tumor cells
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:9/24/2017)... ... September 23, 2017 , ... Throughout the United States and the world, ... day, physicians, nurses and other providers work to give the best care possible to ... , But U.S. Senators today are threatening to tie our hands in carrying out ...
(Date:9/24/2017)... , ... September 24, 2017 , ... “Star of Bethlehem ... of Bethlehem Study” is the creation of published author, Duane Engdahl, an investigator who ... by Christian Faith Publishing, Duane Engdahl’s new book is a thought-provoking essay an event ...
(Date:9/22/2017)... Lea, MN (PRWEB) , ... September 22, 2017 , ... ... video) at its rally to interview citizens on why they are rallying against Mayo ... and commitment to this effort against Dr. Noseworthy’s (CEO) decision to close the Albert ...
(Date:9/22/2017)... ... September 22, 2017 , ... ... financial setbacks, a senior finds a new lease on life with assistance from ... of people resolve their problem with unsecured debt. The senior is one of ...
(Date:9/22/2017)... ... 2017 , ... “Cursed with a Curse: The Truth about ... freedom experienced when breaking free from this misconception. “Cursed with a Curse: The ... Published by Christian Faith Publishing, Lysa M. Harrison’s new book is a powerful ...
Breaking Medicine News(10 mins):
(Date:9/9/2017)... -- ... Washington DC ... 12 th – Monday, September 18 th .The Brain Tumor Foundation ... scans to the public.Where:  BTF,s Mobile MRI Unit ... Street NW, Washington, D.C.What:BTF brings its nationwide initiative, the Road to Early ...
(Date:9/7/2017)...  Eli Lilly and Company (NYSE: ... to more efficiently focus resources on developing new ... workforce reductions, including those from a U.S. voluntary ... 3,500 positions. With the streamlining ... approximately $500 million that will begin to be ...
(Date:9/7/2017)... NuvoAir (formerly called Pond Healthcare Innovation), the company ... Novartis Pharma AG to distribute NuvoAir,s spirometry technology to physicians ... spirometry platform and Novartis, commitment to address the unmet medical ... ... "We ...
Breaking Medicine Technology: