Free Republic
Browse · Search
General/Chat
Topics · Post Article

Skip to comments.

Advances In "Micro" RNA Exploring Process Of Life
Science Daily ^ | 9/23/2002

Posted on 09/23/2002 11:51:18 AM PDT by sourcery

CORVALLIS, Ore. – Researchers at Oregon State University have made an important advance in the understanding of "micro-RNA" molecules, which are tiny bits of genetic material that were literally unknown 10 years ago but now represent one of the most exciting new fields of study in biology. The findings will be reported Friday in the journal Science.

They reveal for the first time a new mechanism by which micro-RNA can stop the function of messenger-RNA by literally cutting it in half, interfering with the normal function of specific messenger RNAs in gene expression.

This "expression" of genes that code for essential proteins is ultimately what controls whether a cell turns into a lung, liver, brain or other cell. Understanding what activates this process – or stops it – is a key to understanding the biological process of life itself, and forms the foundation for advances in medicine, agriculture and other fields.

On this frontier of biology, experts say, the most intriguing new component is micro-RNA, a minuscule type of regulatory molecule that had seemed insignificant even in the extraordinarily tiny, microscopic world of cell biology.

The first micro-RNA, in fact, was only discovered in 1993 and at the time was thought to be a biological oddity in worms. A couple hundred have since been discovered in both plants and animals. But it has only been in just the past few months that scientists working in this area have come to understand the potentially profound importance of micro-RNA.

"For a long time, people really did not know that these micro-RNAs were even there," said James Carrington, professor and director of the OSU Center for Gene Research and Biotechnology. "They were under the radar, and observations of them were limited by our technology. But as we learn more about these regulatory molecules, we're beginning to understand the scope of their biological importance. In molecular biology, micro-RNAs are clearly one of the top two or three discoveries of the past decade."

Every normal cell in complex organisms, such as plants, flies and humans, has a complete copy of the DNA for the entire organism, some 15,000 to 35,000 genes that collectively are thought of as the genetic blueprint for life. But to serve as certain types of cells, such as brain in humans or roots in plants, only a much smaller number of genes within each cell are actually "expressed," or allowed to create the proteins that perform these separate life functions.

"A key focus in biology for a long time has been what controls gene expression," Carrington said.

It is well understood, Carrington said, that two of the key steps between DNA and a functional cell are the processes of transcription and translation. In transcription, single-stranded "messenger RNA" molecules that correspond to each expressed gene are produced. And in translation, the messenger RNA is decoded, resulting in the production of a protein made from some combination of 20 amino acids.

"This is a very complex series of biological processes that requires hundreds of proteins and other factors," Carrington said. "And we're now also learning the role of micro-RNA in controlling expression of some important genes."

Micro-RNAs are actually produced by the transcription of tiny genes, in regions of the genome that were previously thought to be vacant or useless DNA. However, unlike messenger RNAs, micro-RNAs are not translated to produce proteins. Instead, researchers are finding that these micro-RNAs have critical functions in controlling the process of gene expression.

In some recent studies, other scientists found that micro-RNAs can bind to specific messenger RNAs to block the translation or decoding process. In the latest advance made by the OSU researchers, micro-RNAs in the plant Arabidopsis thaliana were found to destroy messenger RNAs instead of blocking its function, by literally cutting it in half.

"Much of our understanding of cell biology is related to this area we call negative regulation, or the processes that stops genes from being expressed," Carrington said. "Anything that improves our knowledge of this process could be quite significant."

For one thing, Carrington said, micro-RNAs might be intimately involved in the normal function of stem cells, those biologically unique cells that, when reproducing, can produce either more stem cells or begin a line of cells that is differentiated into something else, a brain, lung or liver cell.

"It's very important that we learn how cells differentiate and grow normally," Carrington said. "Just about everything in the human body has a genetic component. Genetic abnormalities relate to birth and developmental defects, susceptibility to disease, misregulation of genes. And these same processes are also at work in all other life forms, including plants, and new findings could be applied to crop biotechnology or even traditional plant breeding."

Continued research, Carrington said, will almost undoubtedly find human genetic defects that can be traced to dysfunction of micro-RNAs.

This broad area of research, officials say, has such promise that major new studies are being developed across the nation.

OSU was recently the recipient of a 4-year, $1.7 million grant from the National Science Foundation to study micro-RNAs in Arabidopsis, a plant that works well as a model for genetic research, and the researchers will try to identify the functional messenger RNA targets of different micro-RNAs.

Scientists expect that some of the life processes controlled by micro-RNAs in plants will have been conserved across millions of years of evolution and operate the same way in animals, including humans.

--------------------------------------------------------------------------------

Note: This story has been adapted from a news release issued by Oregon State University for journalists and other members of the public. If you wish to quote from any part of this story, please credit Oregon State University as the original source. You may also wish to include the following link in any citation:

http://www.sciencedaily.com/releases/2002/09/020920072040.htm


TOPICS: Science
KEYWORDS: crevolist
Navigation: use the links below to view more comments.
first 1-2021-4041-53 next last

1 posted on 09/23/2002 11:51:18 AM PDT by sourcery
[ Post Reply | Private Reply | View Replies]

To: sourcery
read later
2 posted on 09/23/2002 12:02:46 PM PDT by LiteKeeper
[ Post Reply | Private Reply | To 1 | View Replies]

To: PatrickHenry
Do you have a biogenetics ping list?
3 posted on 09/23/2002 12:05:39 PM PDT by balrog666
[ Post Reply | Private Reply | To 2 | View Replies]

To: VadeRetro; jennyp; Junior; longshadow; *crevo_list; RadioAstronomer; Scully; Piltdown_Woman; ...
RNA world ping.
4 posted on 09/23/2002 1:36:32 PM PDT by PatrickHenry
[ Post Reply | Private Reply | To 3 | View Replies]

To: sourcery
Before it's pulled bump.
5 posted on 09/23/2002 1:39:58 PM PDT by js1138
[ Post Reply | Private Reply | To 1 | View Replies]

To: js1138
"Before it's pulled"? Oh, ye of little faith... ;)
6 posted on 09/23/2002 1:56:41 PM PDT by general_re
[ Post Reply | Private Reply | To 5 | View Replies]

To: PatrickHenry
"Mark for later" bump.
7 posted on 09/23/2002 1:57:57 PM PDT by VadeRetro
[ Post Reply | Private Reply | To 4 | View Replies]

To: general_re
Is gravity low today? The science threads are dying of natural causes. Of course they are way over my head and don't have any sexy immediate implications.
8 posted on 09/23/2002 1:59:36 PM PDT by js1138
[ Post Reply | Private Reply | To 6 | View Replies]

To: js1138
The science threads are dying of natural causes. Of course they are way over my head and don't have any sexy immediate implications.

Kinda like this thread?

Underage and selling their sexuality on the Web :P

9 posted on 09/23/2002 2:05:52 PM PDT by JediGirl
[ Post Reply | Private Reply | To 8 | View Replies]

To: js1138
Is gravity low today?

Depends on where you are...

10 posted on 09/23/2002 2:10:45 PM PDT by general_re
[ Post Reply | Private Reply | To 8 | View Replies]

To: sourcery
OSU was recently the recipient of a 4-year, $1.7 million grant from the National Science Foundation

This would be the reason for the article. A little PR. Publish or perish.

11 posted on 09/23/2002 2:14:25 PM PDT by RightWhale
[ Post Reply | Private Reply | To 1 | View Replies]

To: sourcery
Here us the actual abstract from the Science article

Science 2002 Sep 20;297(5589):2053-6



Cleavage of Scarecrow-like mRNA targets directed by a class of
Arabidopsis miRNA.

Llave C, Xie Z, Kasschau KD, Carrington JC.

Center for Gene Research and Biotechnology, and Department of Botany and Plant Pathology,
Oregon State University, Corvallis, OR 97331, USA.

Micro-RNAs (miRNAs) are regulatory molecules that mediate effects by interacting with
messenger RNA (mRNA) targets. Here we show that Arabidopsis thaliana miRNA 39 (also
known as miR171), a 21-ribonucleotide species that accumulates predominantly in inflorescence
tissues, is produced from an intergenic region in chromosome III and functionally interacts with
mRNA targets encoding several members of the Scarecrow-like (SCL) family of putative
transcription factors. miRNA 39 is complementary to an internal region of three SCL mRNAs.
The interaction results in specific cleavage of target mRNA within the region of complementarity,
indicating that this class of miRNA functions like small interfering RNA associated with RNA
silencing to guide sequence-specific cleavage in a developmentally controlled manner.
12 posted on 09/23/2002 2:28:31 PM PDT by tallhappy
[ Post Reply | Private Reply | To 1 | View Replies]

To: tallhappy; js1138
Well, the science threads wouldn't be dying if they all referred to cleavage.

Cleavage of Scarecrow-like mRNA targets...

Scarecrow cleavage -- better than nothing, I guess.....

13 posted on 09/23/2002 2:46:28 PM PDT by r9etb
[ Post Reply | Private Reply | To 12 | View Replies]

To: r9etb
Science threads die because a bunch of ignorant religious zealots turn it in to some sort of proselyization for their evolutionist religion.

It turns interesting threads in to boring beat-a-dead-horse threads.

14 posted on 09/23/2002 2:49:42 PM PDT by tallhappy
[ Post Reply | Private Reply | To 13 | View Replies]

To: r9etb
Also, how much is there to say? These miRNA's are great findings and indicate a new way to regulate gene expression. It is a fine tuning of the system and the extent of it is still hardly known.

In this system, it is quite interesting that the genes they are regulating by cleavage are themselves transcription factors -- ie they themselves are genes that regulate gene expression.

It's a quick way to turn off the genes regulated by scarecrows.

15 posted on 09/23/2002 2:54:28 PM PDT by tallhappy
[ Post Reply | Private Reply | To 13 | View Replies]

To: tallhappy
I find that cleavage piques my interest in genetic expression....

(OK, so I'm in the gutter again.)

16 posted on 09/23/2002 3:04:03 PM PDT by r9etb
[ Post Reply | Private Reply | To 15 | View Replies]

To: tallhappy
Science threads die because a bunch of ignorant religious zealots turn it in to some sort of proselyization for their evolutionist religion.

Well, thanks for kicking things off, Mr Shortgrumpy!

17 posted on 09/23/2002 3:30:03 PM PDT by balrog666
[ Post Reply | Private Reply | To 14 | View Replies]

To: tallhappy
Science threads die because a bunch of ignorant religious zealots turn it in to some sort of proselyization for their evolutionist religion.


I am sure that you actually meant to say.....

Science threads die because a bunch of ignorant religious zealots turn it in to some sort of prostelyization for their Creationist myth.

Oops, there I went and did it.
18 posted on 09/23/2002 4:12:24 PM PDT by Aric2000
[ Post Reply | Private Reply | To 14 | View Replies]

Comment #19 Removed by Moderator

To: PatrickHenry
You realize, of course, that this discovery totally refutes evolution.
20 posted on 09/23/2002 5:23:02 PM PDT by Condorman
[ Post Reply | Private Reply | To 4 | View Replies]


Navigation: use the links below to view more comments.
first 1-2021-4041-53 next last

Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.

Free Republic
Browse · Search
General/Chat
Topics · Post Article

FreeRepublic, LLC, PO BOX 9771, FRESNO, CA 93794
FreeRepublic.com is powered by software copyright 2000-2008 John Robinson