RNA research update

[Guest guest]

New technique could clarify RNA's role in controlling blueprint of

life

14 Jun 2005 Medical News Today

A team of scientists at the University of Chicago has developed a non-

invasive laboratory technique that allows them to instantly map when

genes are switching off and on in a living bacterium as it becomes

exposed to antibiotics and other changes in its environment.

The technique, which is announced in the Monday, June 13 issue of the

Proceedings of the National Academy of Sciences, could help

scientists discover new drugs and learn to what extent some RNA

molecules help control the blueprint of life.

" The standard assumption has been that DNA encoding for proteins was

the sole actor to control the blueprint for all of life, " said

Philippe Cluzel, an Assistant Professor in Physics at the University

of Chicago. " After announcing the completion of the human genome,

biologists have realized that the DNA sequence wasn't enough to

explain the observed complexity of biological function. "

Cluzel, a biophysicist, co-authored the PNAS article with Thuc Le,

Sebastien Harlepp, Calin Guet, Dittmar, Thierry Emonet and

Tao Pan, all of the University of Chicago. Their research was funded

by the National Institutes of Health and the University of Chicago's

Materials Research Center for Science and Engineering and the

Institute for Biophysical Dynamics.

Cluzel compares the unaccounted-for complexity of biological function

today to the situation 20 years ago in astronomy, when scientists

realized that the celestial objects visible to them did not contain

enough gravity to explain the motion of galaxies. " They proposed the

hypothesis that the motion of galaxies is affected by the presence of

invisible matter called 'dark matter,' " Cluzel said.

In recent years, astronomers have rushed to design experiments that

might help them determine what dark matter is made of. " RNA molecules

could be called the 'dark matter' of biology, " Cluzel said.

Biologists have long known that RNA serves as an important

intermediary between DNA and the factories throughout the cell that

produce proteins. Some biologists have recently begun to identify

families of RNA molecules that also play a major role in determining

when and how genes are turned on and off, but they have lacked the

ability to monitor action of these molecules as it happens within a

single living cell.

Now Cluzel and his associates, using a technique called fluorescence

correlation spectroscopy (FCS), have shown how to monitor the link

between RNA synthesis and promoters-small pieces of DNA that turn

genes on and off-in a living cell.

" Because RNA molecules are intrinsically unstable, it has been

extremely challenging to measure and characterize the mode of action

of RNA molecules within a living cell, " Cluzel said.

The techniques previously used to study RNA required killing and

breaking up a cell in order to extract an RNA molecule. With those

techniques, " one cannot detect in real time the underlying dynamics

of RNA synthesis associated with cellular activities, " he said. But

the scientists in his laboratory have found a way around this with a

technique called fluorescence correlation spectroscopy (FCS).

First, they use an RNA molecule that will bind to a protein called

MS2. This MS2 protein also is fused to a green fluorescent protein

that a laser can detect within a microscopically small volume.

In the absence of RNA, the MS2 fused to the fluorescent protein moves

rapidly. But when bound to RNA, the fused proteins move more slowly.

From the speed of motion, " we can infer the concentration of RNA

present inside the detection volume and a single living cell, " said

Thuc Le, a graduate student in Biochemistry & Molecular Biology and

the lead author of the PNAS paper.

This new technique will now facilitate research that may reveal how

RNA molecules, like proteins, turn genes on and off, Cluzel said.

http://www-news.uchicago.edu

[Guest guest]

Thanx Gretchen:

I also just read this article. I knew u would post this article.

" This new technique will now facilitate research that may reveal how

RNA molecules, like proteins, turn genes on and off, Cluzel said. "

Turn genes on and off, CMT = duplicate genes (some cases), maybe

turned off genes in some cases.

CMT = genetic disorder

HMMMMMM!! Makes me think!

Don't u just love science.

Take care all.