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.
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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
Nope, he meant evolutionists. While Patrick was away there were no problems on the science threads. As soon as he got back two of them got pulled. And of course, he takes pride in his nefarious work.
Actually this discovery is another one in which genes are silenced by the organism. One of the functions of such silencing is to suppress the activity of mutated genes. Organisms have quite a few tactics for fixing mutations and errors. It has nothing to do with an 'RNA World' the micro-RNA is coded by DNA just as regular RNA is a transcription from DNA. This is indeed another kick at stupid evolution theory which claimed that all DNA between genes was junk. But then as medved used to say, this is no problem for evolutionists because it does not refute the prime process by which evolutio takes place - abracadabra shazam.
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There's a rumor going around that everything refutes evolution.
If you are speaking of Darwininianism, it really doesn't take this much.
It is said, Friend Henry, that a rumor run around the world before the truth gets its boots on.
Medved used to say many things-- f'rinstance, that our (approx.) 20,000 year old Earth was once a satellite of Saturn and that the Grand Canyon was carved by an electrical discharge. Those statements are also rather poorly supported. I expect that contributed to his removal from this forum.
Now, I expect someone to flame me for sliming the name of an individual who is no longer around to defend himself. I'm wearing asbestos boxers specifically in anticipation of such an event; I hope not to be disappointed.
(They're kind of itchy.)
Better...
NO, it is the attitude expressed here ---Those statements are also rather poorly supported. I expect that contributed to his removal from this forum. ---that is of low merit.
Free expression of ideas except for those I deem strange. He harmed no one.
Medved used to say many things-
Yup, but you cannot refute the above. Instead you resort to the usual mode of evolutionist argument of character assassination by lies and distortion. You should be ashamed of yourself.
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Where have I lied? And what did I distort?
You have more integrity than that Andrew; don't put words in my mouth. "Poorly supported." By which I mean, "a noteworthy absence of observations that might lead to such a conclusion."
Strange? Sure. I'm all about strange. And there are many strange theories out there. Some of them, however, are more valid than others, by virtue of support from equally strange observations.
I have no problem with anyone who wants to float a new idea. As long as support and defense is part of the package. Are you willing to defend Medved's theories?
I apologize, if you feel I put words in your mouth, but the statement was illustrating my interpretation of your post. How else can I say it? I might have explicitly labeled it as an interpretation, but I assumed that it would be viewed as an interpretation.
Again the whole point of my statement is that every person has equal access to expression of whatever ideas come to their mind in something we call free debate. If it is not free debate, then fine, state so. The fact that one has freedom to express their views is not connected to the believability or acceptance of those ideas. But in order to have any chance at such acceptance or believability they must be expressed. Even ideas rejected as foolish and silly considering their "obvious" disharmony with observation, e.g. the sun does move and the earth doesn't, after quite a long period of rejection and ridicule may ultimately turn out to be the "truth". In any case I do not have to espouse any particular theory in order to support its expression.
Medved did not engage in free debate. He was more interested in grandstanding and posturing than actual debate. Countless critiques and corrections of his work have been offered and ignored, dating back to (at least) 1995. Critics were "oppressors" and "censors," and the substance of the objections were almost uniformly disregarded.
The fact that one has freedom to express their views is not connected to the believability or acceptance of those ideas.
I agree.
But in order to have any chance at such acceptance or believability they must be expressed. Even ideas rejected as foolish and silly considering their "obvious" disharmony with observation, e.g. the sun does move and the earth doesn't, after quite a long period of rejection and ridicule may ultimately turn out to be the "truth". In any case I do not have to espouse any particular theory in order to support its expression.
Here is where we diverge. I would amend your statement this way: "But in order to have any chance at such acceptance or believability they must be expressed supported, and defended." The mere expression of an idea is not enough. I submit that refrigerators work because tiny leprechauns run about the shelves waving hand-held fans at the food. They get their energy by drinking milk straight from the bottle, which is why I sometimes find empty milk cartons in the morning.
Silly and harmless, of course. But if I persisted in posting that theory over the course of a decade or so, refusing to provide any evidence in support of the theory, paying no heed to any evidence to the contrary, and refusing to alter the substance of that idea in any meaningful way, then one might rightly begin to suspect there was a pathology at work.
But enough about dear departed Ted. Your larger implication, that I seek to prevent the free expression of ideas, is nonsense. I would expect, however, that an idea stand up to fairly rigorous scrutiny or else be discarded. I come up with some pretty wacky thoughts in the course of a day. Some of 'em even work; the rest are tossed back. If you have a theory that fits the facts as well or better, throw it on the table, let's give it a once-over and beat it as brutally as we have the theory of evolution.
Whether you seek to prevent the free expression is something I cannot determine. Only you can determine that. What I can say is that the effect of banning someone for his ideas is to engage in the suppression of free expression.
I was going to present medved's last post in order to show you that he was engaged in discussion of something other than his pet theories. The thread however, has been pulled. Once it was moved to the back room I refused to engage in the discussion because the premise there is to engage in uncivil discourse. The results are now obvious. PH got what he sought.
Well, it was a fun ride and I made a LOT of great friends on Free Republic... including one who came to my wedding. But nothing lasts forever, and maybe in a way it's a *good* thing, 'cuz there's no convincing some people that no increase in power makes that power any more pure. JimRob has drummed me out of Free Republic. Here's the reason he put on the screen that popped up on my end: Your posting privilege has been revoked. Reason: Democrat Now, I'm not a Democrat. Haven't been one since 1994 when I changed to Republican, and haven't changed that (yet). |
I will note three observations before abandoning the medved train of thought: First, JimRob, not PH, banned medved. Second, while every individual has the right to freely express his ideas, it is incumbent upon no one to provide the forum for that expression. And third, if medved wants to start a bulletin board system on his own website, there is nothing to stop him.
As I said, free expression(debate) is of a certain type. If it is not free then so be it. JimRob has no obligation to entertain anybody else's viewpoint. It is his site and he can do whatever he wants. The question is whether it is free debate or not. If it is not free debate then the limits should be delineated. Again, the owner is not even required to do that, however the consequences will be evident in the ensuing discussions. Now JediGirl.
Why are you still harping on this? The horse is dead.
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