Biosingularity

Mechanism of microRNAs deciphered

Posted on: May 20, 2007

Over 30% of our genes are under the control of small molecules called microRNAs. They prevent specific genes from being turned into protein and regulate many crucial processes like cell division and development, but how they do so has remained unclear. Now researchers from the European Molecular Biology Laboratory (EMBL) have developed a new method that uncovered the mode of action of microRNAs in a test tube. The study, which is published in the current online issue of Nature, reveals that microRNAs block the initiation of translation, the earliest step in the process that turns genetic information stored on messenger RNAs into proteins.

The central dogma in molecular biology says that the genetic information stored as DNA is transcribed into molecules of messenger RNAs, which are then translated into proteins. MicroRNAs are small molecules that do not encode proteins themselves but bind to messenger RNAs that do. They function as locks for messenger RNAs and prevent their translation into proteins, but how they bring about this effect and at which stage of protein synthesis they interfere is a long-standing puzzle.

“So far it has been impossible to directly examine how and when microRNAs lock up messenger RNAs,” says Matthias Hentze, Associate Director of EMBL, “because until now all we could look at were messenger RNAs that had already been locked-up within cells. To investigate the locking process itself, we developed a test tube system that recreates close to real life conditions of fruitfly embryos. Adding messenger RNAs to this system we could monitor for the first time how they got locked-up by microRNAs.”

Applying this new system Rolf Thermann, who carried out the research in Hentze’s lab, discovered that miR2, an important microRNA in fruitflies, blocks translation very early on, even before the cellular machinery needed can assemble. Bound by miR2 a messenger RNA molecule is no longer accessible to ribosomes, the complexes that carry out protein synthesis.

“Strikingly, the messenger RNA locked-up in this way looks very similar to a messenger RNA that undergoes translation,” Thermann says. “It is bound by big microRNA complexes that strongly resemble ribosomes, but they are not. This explains why when looking at already locked-up messenger RNA many scientists thought that translation had already started and microRNAs must interfere at a later stage of the process. It will be exciting to determine what these complexes are made of and how exactly they function.”

The new approach to studying micro RNAs in action in a test tube may pave the way to similar studies of human and other microRNAs. MicroRNAs play an important role in various diseases including cancer, diabetes and viral infections. The new in vitro system will not only help shed light on the role of microRNAs in disease, but could also serve as a basis for new methods of drug discovery.

source: European Molecular Biology Laboratory

About these ads

1 Response to "Mechanism of microRNAs deciphered"

Before buying a car from a dealer, family member, friend, or stranger, you should check the car title history to confirm that it has a clean past and won’t cause you headaches in the future. It is your responsibility to do this even if the car appears to drive well and has no visible damages. Here’s what you should keep in mind when reviewing the car title history of an automobile that you’re looking to purchase.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

Enter your email address to subscribe to this blog and receive notifications of new posts by email.

Join 998 other followers

Follow me on Twitter

Medical Professional Database Award

 Doctor

Visitors Now

who's online

Blog Stats

  • 1,412,203 hits

Categories

Top Rated

Flickr Photos

in the mood for Christmas....

La bicicletta è la penna che scrive sull’asfalto.

Balloons over Bagan

be yourself, everyone else is taken.

The Escape Plan

Casino Constanta aerial

Colorado Thunderstorm

Nights of Wonder

Saint-Malo Fort National

Barcode, Oslo, Norway.

More Photos

Maps

Networked blogs

Follow

Get every new post delivered to your Inbox.

Join 998 other followers

%d bloggers like this: