Talk:RNA interference

message: The article should explain which organisms use RNAi. All eukaryotes? Only eukaryotes? AxelBoldt 02:38, 12 February 2006 (UTC)
thread_title: older entries

message: I do not like the use of the word "knockout" to describe RNAi in this article:
:RNAi has recently been applied as an experimental technique to "knockout" genes in model organisms for experimental analysis in determining the function of a gene.
RNAi is not knockout. I have only ever heard knockout used to describe permanent genetic modification. Knockdown is the term that is used for RNA interference universally. Peter Znamenskiy 19:18, 7 June 2006 (UTC)
replies: text: Completely agree - knockdown is correct terminology Goldfinger820 03:57, 8 June 2006 (UTC)
thread_title: Knockout

message: "RNAi is distinct from other gene silencing phenomena in that silencing can spread from cell to cell and generate heritable phenotypes in first generation progeny when used in Caenorhabditis elegans."
This sentence is in the introduction.  There is nothing relating to this sentence in the main text so we need a section on the systemic nature of RNAi silencing.  But first, what are the "other gene silencing phenomena" being referred to here? I assume X-inactivation, imprinting and heterochromatin.  Or is it something else? David D. (Talk) 06:17, 26 July 2006 (UTC)
replies: text: I added a brief mention of the organisms in which RNAi is and is not systemic, but I'm not convinced the lead is really clear. I also think that, after splitting up the overview section, the new section order is a little out of whack. What do you think? Opabinia regalis 00:55, 29 July 2006 (UTC)
thread_title: Question

message: Specifically, Trypanosoma cruzi, in which (I've been told) "post-transcriptional gene silencing" was about as thoroughly charactertized at the time of the Fire/Mello paper as it was in pentunias and worms.  Probably deserves mention under Cellular Mechanism and History.Og0709 13:28, 2 October 2006 (UTC)
thread_title:  Request for addition of other organisms 

message: We should add a paragraph of piRNA and rasiRNA,because it is RNA silencing just a different means. It seems to be germline specific, but it is significant. GetAgrippa 20:19, 7 October 2006 (UTC)
thread_title: Add piRNA

message: Fire and Mello will give their Nobel lectures on December 8. --JWSchmidt 15:50, 2 December 2006 (UTC)
replies: text: In his nobel lecture, Andrew Fire seemed very comfortable using the term "RNA interference" for all of the different mechanisms for inhibition of gene expression that can be triggered by double stranded RNA, including mechanisms at the level of transcription control. --JWSchmidt 21:31, 12 December 2006 (UTC)
thread_title:  Nobel lectures 

message: Can the article's first paragraph be more clear about the definition of RNAi and the relationship between miRNA and RNAi? "RNAi is mediated by the same cellular machinery that processes microRNA, small RNA molecules involved in large-scale gene regulation in the cell." What does "machinery that processes microRNA" mean? Is the intent to make reference to Dicer and the processing of pre-miRNA? Is the intent to make reference to the involvement of the RISC complex in the mRNA-degrading action of a RISC complex nuclease that can be targeted either by siRNA or miRNA?
It seems like there might be two different views about how RNA interference should be defined. According to this article, "RNA interference (RNAi) is a posttranscriptional gene silencing mechanism in eukaryotes, which can be triggered by small RNA molecules such as microRNA (miRNA) and small interfering RNA (siRNA)."  A broad definition of RNA interference would just say that it involves double-stranded RNA, not specifically siRNA. This other article uses "posttranscriptional silencing" as a general term, and lists RNA interference as one mechanism, saying: "A hallmark of RNAi is the presence of small interfering RNAs". They try to distinguish multiple mechanisms by which microRNA can act in posttranscriptional silencing, only one of which involves RNA-dependent RNA polymerase and the production of siRNA from miRNA. So is RISC complex-mediated mRNA destruction called RNA interference even if siRNA is not involved, but only the double-stranded RNA of pre-miRNA hairpins?<BR>--JWSchmidt 18:27, 2 December 2006 (UTC)
replies: text: About a month ago, I got about a third of the way through an attempt to make this article and miRNA more consistent with each other, but got distracted and never really finished. The informal usage I'm familiar with restricts "RNA interference" to gene silencing that is the result of siRNA, most generally when artifically induced. I think a brief section on variations in nomenclauture in the literature might be in order, especially since there were so many names given to related phenomena before the mechanism was identified. Opabinia regalis 00:46, 3 December 2006 (UTC)

text: Sounds like we should use the broader definition then. No objections. IIRC I wrote or rewrote both Dicer and the material you mention in miRNA, so I apologize for being inconsistent :) This is a fast-moving field and I am probably well out of date. Opabinia regalis 05:58, 3 December 2006 (UTC)
replies: text:  The literature for this rapidly advancing research topic area reads like the reports from a group of blind people exploring an elephant. I hope that the Nobel prize will encourage someone to step back, take a look at the whole picture and write a great review article. The majority of people who are publishing articles about RNAi are trying to use it as a laboratory tool and those folks seem to have a rather simplified view of RNAi. The relatively few labs that are studying the details of the endogenous RNAi processes keep reminding everyone that there is still much to learn. I think the Wikipedia Argonaute article needs an adjustment; it seems too centered on siRNA. "In some cases, including Caenorhabditis elegans, distinct Argonaute proteins function in conjunction with siRNAs and microRNAs, respectively. In other animals, the same Argonaute can function with both siRNAs and microRNAs" (source). The authors of that article suggest a very broad definition of RNAi, "a variety of transcriptional and post-transcriptional gene-silencing processes that are collectively referred to as RNA-mediated interference". I just re-worked the introduction to RNA interference and tried using a definition of RNAi that is limited to post-transcriptional gene-silencing by targeted RNA destruction guided by either siRNA or miRNA. Maybe even that definition is too narrow. --JWSchmidt 16:56, 3 December 2006 (UTC)
thread_title:  relationship between miRNA and RNAi 

message: :After listening to the Noble Prize lectures, I have updated the introduction of the article to use the broad definition of RNA interference which includes gene regulation at both transcriptional and post-transcriptional levels. --JWSchmidt 21:43, 12 December 2006 (UTC)
thread_title: Broad definition of RNAi

message: This is an area of intense interest and rapid growth. I noted two new RNAi related articles in my Jan. Science:
Distinct Populations of Primary and Secondary Effectors During RNAi in C. elegans Julia Pak and Andrew Fire
Science 12 January 2007: 241-244. 
  
Secondary siRNAs Result from Unprimed RNA Synthesis and Form a Distinct Class 
Titia Sijen, Florian A. Steiner, Karen L. Thijssen, and Ronald H. A. Plasterk
Science 12 January 2007: 244-247. GetAgrippa 04:28, 1 February 2007 (UTC)
thread_title: New articles

message: I think that the figure in this article might be a good addition. --Peta 01:23, 15 February 2007 (UTC)
replies: text: Thanks. I like the way this one is organized better. Since BMC doesn't explicitly refer the creative commons licenses in the open-access statement, though, I'm not sure how to tag this. Opabinia regalis 01:47, 15 February 2007 (UTC)
replies: text: It's there on the page: this is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0). This is considered a free license for the commons. --Peta 01:49, 15 February 2007 (UTC)
replies: text: Well, I'm unobservant then ;) I was looking in the linked open-access charter. Appearing imminently. Opabinia regalis 02:04, 15 February 2007 (UTC)
replies: text: Neat, should this stub on P-bodies be linked somewhere?--Peta 02:34, 15 February 2007 (UTC)
replies: text: It is, but they're called GW bodies in the text. I guess that should be changed to match the image. Opabinia regalis 02:36, 15 February 2007 (UTC)

text: On second thought, I think I like it better in the variations section - that way it comes after the introduction of all the proteins that are labeled in it, and is located in the text with the discussion of P-bodies/GW-bodies. The existing lead image also explicitly includes siRNA production, which I think is important to show early on. Opabinia regalis 02:36, 15 February 2007 (UTC)
replies: text: I think it works well where you have put it. On a different note I think that the cellular mechanism section could use a little introduction before it plunges into taking about cleavage. I think 2-3 sentences explaining that the process occurs in the cytoplasm; and that miRNAs have to be actively shifted from the nucleus, and siRNAs imported into a cell to be processed this way. Where things happen in cells is pretty important to understanding the process.--Peta 03:26, 15 February 2007 (UTC)

text: A little copy-editing note: "Dicer" is not capitalized consistently. –Outriggr § 04:30, 15 February 2007 (UTC)
replies: text: Thanks, I think I got them all now. It used to be consistently capitalized in the literature and now is varied - a lot of papers seem to use Dicer for the original protein and dicer for all homologs, bu that's probably not a sustainable distinction. Opabinia regalis 04:59, 15 February 2007 (UTC)
thread_title: Plant and animal differences

message: Hi, the present lead seems kind of daunting for non-experts, since it relies on knowledge that many people won't be familiar with.  I at least had a little trouble following it, although maybe that's just me. :(  Perhaps we could replace it with something written at a slightly lower level?  Here's an initial draft
:RNA interference (also called "RNA-mediated interference", abbreviated RNAi) is a mechanism for inhibiting gene expression in which the messenger RNA (mRNA) for a specific gene or set of genes is digested, preventing it from being translated in the corresponding protein(s).   The RNAi mechanism is thought to have evolved early in the history of life and is substantially the same, i.e., conserved, in most eukaryotic organisms.  RNAi serves as a form of innate immunity against viruses, and also plays major roles in regulating development and genome maintenance.
:The central ribonuclease of the RNAi pathway is the argonaute protein, which is part of a multi-protein complex called RISC.  To be activated, the complex must be first "armed" with a single strand of RNA, typically 20-25 nucleotides long; the argonaute protein digests only mRNA that can hybridize with this guide strand.  This allows RNAi to suppress specific genes independently of one another; yet it is also a very general system, since the RISC complex may bind nearly any guide strand.  The various guide strands are produced by the digestion of ’’double-stranded’’ RNA (dsRNA); the resulting fragments are known as small interfering RNA (siRNA) when derived from foreign genetic material and as microRNA (miRNA) when derived from the cell's own genome. 
:RNAi is an effective method for post-transcriptional gene silencing, making it a valuable in vivo laboratory research tool, both in cell culture and in living organisms. For example, synthetic dsRNA may be introduced into cells to induce RNAi suppression of the encoded genes. RNAi may also be used for large-scale screens that systematically shut down each gene in the cell, which can help identify the components necessary for a particular cellular process or an event such as cell division. RNAi is also a promising therapy in human disease, such as...(please fill me in) 
:RNAi has been particularly well-studied in certain animals such as Caenorhabditis elegans and Drosophila melanogaster, and in plants such as Arabidopsis thaliana.  The earliest signs of RNAi were observed by plant biologists, who described post transcriptional gene silencing and noted that genes could be suppressed by antisense RNA, but also by sense RNA.  The key role of double-stranded RNA in RNAi was discovered in 1998 by Andrew Fire and Craig C. Mello in the nematode worm C. elegans; for this work, they shared the 2006 Nobel Prize in Physiology or Medicine.
Please let me know whether you like this version of the lead.  Feel free to tinker with it as well.  We should wait for Opabinia regalis before doing any substitutions in the main article, though.  
Oh, btw, we also might want a reference for the "human disease" sentence.  Is it mainly good for viral diseases, or has it been used effectively for bacteria and parasites, too?  I haven't looked into it yet.
Hoping that this is useful, Willow 12:03, 15 February 2007 (UTC)
replies: text: I tried to simplify a bit, and describe the major points earlier; what do you think? Willow, the problem with your first sentence is that it doesn't really reflect current usage; see the above discussions about 'broad' vs 'narrow' definitions. The term 'RNAi' now generally refers to RNA-induced downregulation, which isn't necessarily via mRNA degradation. The medicine/biotech sentence is mostly just a pointer to that section; especially in medical applications, people have been talking (over-)excitedly about this for years ('antisense therapy' was certainly proposed before RNAi was discovered) and it's been mostly vaporware till recently. To answer the disease question, it's viruses that are talked about from an 'immune' standpoint, but a lot of the real excitement is in suppressing overexpressed genes in cancer cells. It could be used against other pathogens indirectly, if there were some gene that could be suppressed to bolster the immune response (or, I suppose, if the pathogen would take up the dsRNA delivered to the patient). Opabinia regalis 02:52, 16 February 2007 (UTC)

text: I found the introduction incredibly daunting.  Not very useful for non-experts.  —Preceding unsigned comment added by 98.169.69.1 (talk) 05:49, 16 December 2008 (UTC)
thread_title: Slight re-write of lead?

message: Should there be an article created about it? This article is well researched so I assumed that there was a purpouses on excluding conditional RNA interference. The article touch it from what is implied, but without really covering the subject as it should. Fad (ix) 18:35, 18 February 2007 (UTC)
replies: text: There's only so much that will fit in one article ;) I added a very short sentence on techniques used in mammalian systems, including conditional RNAi using lentiviral vectors, but if you want to create a separate article, that would be great. Opabinia regalis 04:57, 19 February 2007 (UTC)

text: This article should not be addressing conditional RNA interference.  That would be like the genetic recombination article addressing conditonal knockouts. it would be much more useful in some sort of techniques article. David D. (Talk) 05:17, 19 February 2007 (UTC)
replies: text: I would have believed that conditional knockout could be at least cited in the genetic recombination article. But I gess given the size of those articles, it is better off. Opabinian regalis, I have followed the history of this article, you have really done an impressive job. Fad (ix) 06:19, 19 February 2007 (UTC)
replies: text: Thanks ;) I think a sentence on techniques in mammals fit well, since there was already previous discussion of techniques in C. elegans. But an article on conditional RNAi, or on RNAi techniques in general, wouldn't be a bad thing. Opabinia regalis 08:28, 19 February 2007 (UTC)
thread_title: Conditional RNA interference

message: :The selective and robust effect of RNAi on gene expression makes it a valuable research tool, both in cell culture and in living organisms; synthetic dsRNA introduced into cells can induce suppression of specific genes of interest. RNAi may also be used for large-scale screens that systematically shut down each gene in the cell, which can help identify the components necessary for a particular cellular process or an event such as cell division. The RNAi pathway has been particularly well-studied in certain model organisms such as the nematode worm Caenorhabditis elegans, the fruit fly Drosophila melanogaster, and the flowering plant Arabidopsis thaliana. Exploitation of the pathway is also a promising tool in biotechnology and medicine.
At first it appears as if this paragraph is about the various applications of RNAi as a tool: to study the function of specific genes, to perform large-scale screens, to study cellular processes, and in biotech and medicine. But then there is one sentence in the middle that doesn't fit the paragraph's general theme: it tells us that the RNAi pathway has been particularly well studied in model organisms. This sentence is about our knowledge of the RNAi pathway, not about its applications. Further, the last sentence uses "also", implying that the last two sentences somehow talk about the same, but they don't.
I propose that the sentence "The RNAi pathway has been particularly well-studied in certain model organisms such as the nematode worm Caenorhabditis elegans, the fruit fly Drosophila melanogaster, and the flowering plant Arabidopsis thaliana." be moved from the paragraph about RNAi's applications to a section that describes its discovery and study. AxelBoldt 17:00, 4 March 2007 (UTC)
replies: text: I see your point, though I'm not sure it's really unclear; much of the reason RNAi is well-studied in these organisms is that they are the ones in which it is easy to use as a tool (of course, this goes the other way around too; it's easy to use RNAi because the behavior of the pathway is relatively well understood in these organisms...). But the lead definitely doesn't need to get any longer. I tried just moving the 'well studied' sentence to the end of the second paragraph that describes the pathway, which I think fits well with the subsequent text elaborating on the biochemistry, most of which was discovered in these organisms. What do you think? Opabinia regalis 18:00, 4 March 2007 (UTC)
thread_title:  Paragraph in intro 

message: The figure "Illustration of the major differences between plant and animal gene silencing" misspells "asymmetric". I believe under the image's licence we are OK to modify the spelling in the figure, if anyone wants to have a go. Crana 21:12, 4 May 2007 (UTC)
replies: text: I must be missing something... The image appears to have 'asymmetric' spelled 'asymmetric' - i.e. correctly. Am I completely blind? -- MarcoTolo 03:07, 5 May 2007 (UTC)

text: No, you're not going mad. Your original comment was correct. I saw your comment an then corrected the version in commons.  Sorry for the confusion. David D. (Talk) 17:53, 7 May 2007 (UTC)
thread_title:  Misspelling in figure 

message: I just uploaded an elegant, simple diagram of RNAi from PLoS to the commons here.  Have a look if you're interested. Calliopejen1 16:55, 5 August 2007 (UTC)
thread_title:  free image 

message: In the intro it stated that siRNA only derived from exogeneous sources. This isn't true, it derives from the dsRNA of the same cell, it implies that only humans create siRNA or atleast only other cells create the siRNA that a particular cell requires. I've changed it but i'm not certain if the terminology is correct. All i know is that its more accurate than before. I was surprised to find such an error in the introduction of a featured article to be honest. Perhaps there are other mistakes as I have neither studied this article nor know enough about RNAi to comment. But a check through should definately be required as a featured article suggests that almost everything it contains is correct which doesn't seem to be the case.  —Preceding unsigned comment added by 86.133.236.247 (talk) 12:04, 23 October 2007 (UTC)
thread_title:  siRNA 

message: This is  a superb, outstanding article, the best on the web. My congratulations to all editor.--GrahamColmTalk 21:50, 10 February 2008 (UTC)
replies: text: What's wrong with review articles? But since the article you mentioned is free I it doesn't hurt to include it, plus it is better in terms of detail than the nature news. It doesn't mention their miRNA findings though. Narayanese (talk) 21:25, 21 February 2008 (UTC)
thread_title: Superb article

message: Did I get it all right? I've been taught it is viral RNA-dependent RNA polymerase that makes dsRNA from a ssRNA and starts RNAi, but the presence of endogenous RdRPs in RNAi makes it a little confusing. Narayanese (talk) 20:37, 18 March 2008 (UTC)
replies: text: In  plants and drosophila it is the endogenous RDRP that is important for amplification of the siRNA's.  Mutants in those genes are less effective in silencing. Mammals do not have the activity. David D. (Talk) 03:28, 19 March 2008 (UTC)
replies: text: Ah, so that endogenous RdRP has a limited role after all. Thanks. Narayanese (talk) 09:22, 19 March 2008 (UTC)
thread_title:  Lead picture 

message: The article seems to lack any information about the work done on three species of trematode. Donek (talk) 22:42, 2 November 2008 (UTC)
thread_title:  What about parasitic flatworms? 

message: The "dsRNA cleavage" section confuses me. Paragraph 1 says that dsRNA activates dicer to cleave it, then they are broken into single strands and, finally, the siRNAs are incorporated into RISC. Paragraph 2 seems to start at the beginning again describing how an effector protein detects the dsRNA and then the effector protein stimulates dicer to cleave the dsRNA and that both the effector protein and dicer present the siRNAs to RISC. Have I misunderstood this or is there a problem with the section? Donek (talk) 16:26, 18 November 2008 (UTC)
thread_title:  Cellular Mechanism 

message: What is the difference between RNA silencing and RNA interference. Is it just that RNA silencing is in plants, and RNA interference is in animals, or is there more to it than that? If so, shouldn't the pages be merged? SiameseTurtle (talk) 19:07, 19 December 2008 (UTC)
thread_title:  RNA silencing 

message: In the second paragraph, the term dsRNA is used without prior definition. thanks.  —Preceding unsigned comment added by 128.249.96.253 (talk) 18:32, 23 January 2009 (UTC)
thread_title:  undefined term 

message: My understanding is that post transcriptional gene silencing (PTGS) originally referred to gene silencing effects in plants. This turned out to be a result of RNA interference and now PTGS rather describes the effects of RNA interference. I think this is already well covered in the lead paragraph and History and discovery sections; so I suggest PTGS should just redirect to RNA interference. Any problems with this? Ribrob (talk) 16:25, 11 April 2009 (UTC)
thread_title: Merge with post transcriptional gene silencing

message: "The relevance of observations from fission yeast mating-type regions and centromeres to mammals is not clear, as heterochromatin maintenance in mammalian cells may be independent of the components of the RNAi pathway.[45]" a paper i have been reading published 2009 suggests that heterochromatin maintenance in yeast might be independent of RNAi as well... is an small update needed?
Alexander Kagansky, Hernan Diego Folco, Ricardo Almeida, Alison L. Pidoux, Abdelhalim Boukaba, Femke Simmer, Takeshi Urano, Georgina L. Hamilton, Robin C. Allshire (2009) Synthetic Heterochromatin Bypasses RNAi and Centromeric Repeats to Establish Functional Centromeres,  Science 324, 1716  —Preceding unsigned comment added by X CheshireCat x (talk • contribs) 16:16, 15 December 2009 (UTC)
replies: text: I have not read the paper but I'm not sure that the fact that synthetic centromeres don't require RNAi does not negate the fact that real centromeres in yeast do use, and require, a functional RNAi process to maintain their heterochromatin. David D. (Talk) 16:28, 15 December 2009 (UTC)
thread_title: new research

message: PATENTLY, A BATTLE FOR GENETICS' NEXT BIG THING
Who invented hairpin gene silencing? It's literally a $64 million
question, as the claimants to one of the most valuable biotechnology
patents of the past decade begin skirmishing over its ownership.
Hairpin gene silencing, also known as RNA interference (RNAi), is a
simple, quick, but exquisitely precise way of exploring gene function in
higher organisms - it can be applied to switching off genes in plants,
animals, insects, or any other higher organism. Changes in the organism
then provide cues the function of the silenced gene.
There are four contenders: CSIRO Plant Industry, the multinational life
science company Syngenta (UK), the Carnegie Institute in the US, and a
partnership involving small Queensland-based biotechnology company
Benitec Australia and the Queensland Department of Primary Industries (QDPI).
CSIRO lays claim to having discovered hairpin gene silencing in 1994;
CSIRO Plant Industry molecular geneticist Dr Peter Waterhouse performed
the first successful gene-silencing experiment in a plant - tobacco - in 1995.
CSIRO's claim rests on its belief that Waterhouse's experiment was also
the first demonstration of this novel method of gene silencing in any
organism.
But CSIRO delayed lodging its patent until April 1998; the Benitec/QDPI
partnership and Syngenta filed in March 1998. In the intervening period,
the Carnegie Institute and Syngenta filed their applications - Carnegie
filed on the basis of demonstrating hairpin gene silencing in the
nematode Caenorhabditis elegans.
Dr Rob Defeyter, a member of Waterhouse's team, and now IP manager for
Plant Industry, said the division prepared a draft patent in 1995, but
delayed filing while it conducted further research.
"Our laboratory notebooks confirm we continued our research between 1995
and 1998, mainly to confirm our data, extend the technique, and find out
how broadly applicable it might be," Defeyter said.'''
Benitec's claim is based on work done by former Plant Industry geneticist
Dr Mick Graham, who worked with Waterhouse until 1995 before joining QDPI.
Graham was the first to demonstrated successful dsRNA silencing in
mammalian cells, and the Benitec/QDPI alliance was the first to file a
patent on the technique, in March 1998. The question of ownership is
complicated by different views of what constitutes priority. Defeyter
said patent offices in most countries, including Australia, based
priority on the filing date, but the US Patent Office bases priority on
the date of invention - even if the patent application is not lodged
until later.
Yesterday CSIRO announced it was releasing the high-throughput gene
silencing vectors it has developed for its own work in plants, or free
use by any not-for-profit research organisation.
Today, Benitec announced a collaborative agreement with US biotechnology
company Tranzyme, in North Carolina, to develop and market its own high-
throughput gene-silencing and gene-delivery technologies.
In their joint press release, the companies said the combination of
Benitec's High Throughput (HTP) gene silencing technology announced on
January 7, 2003, with Tranzyme's industry-proven gene delivery and
expression technology, would "offer customers a revolutionary means of
producing gene 'knockdowns' quickly and efficiently.
"The combined technologies will be ideal for both in vitro and in vivo
applications," it said. "The collaboration will target the pharmaceutical
industry and will fast-track the discovery and validation of drug
targets." The companies will share revenues, as well as developing their
own proprietary targets using the combined technology for future joint
commercialisation.
CSIRO's press release yesterday said its gene vectors can be used to
identify the function of thousands of genes quickly and accurately, and
predicted the technology would promote "major advances in biotechnology
and agriculture".
Plant Industry Chief Dr Jim Peacock said, "Scientists can now accurately
and rapidly identify the function of single genes or specific groups of
genes from tens of thousands of genes in an organism." "As well as the
speed of analysis, these vectors provide nearly 100 per cent efficiency
in 'switching off' any gene under investigation. This means the effect of
a gene in an organism can be determined confidently, and once its
function is known we can decide how to use this information." Harbinger
of attack Waterhouse's original 1995 experiment confirmed the existence
of plant cells of an ancient mechanism, perhaps evolved as a defence
against viruses, that detects the presence of double-stranded RNA
molecules - a harbinger of viral attack.
When viruses infect living cells, they produce a double-stranded RNA
(dsRNA) copy of their genetic blueprints as a prelude to mass-replicating
new virus particles.
The anti-viral mechanism detects the dsRNA genetic blueprint, and by an
as yet unidentified mechanism, cleaves it into useless fragments, halting
the virus replication before it can begin. It is now clear that the cells
of higher organisms use the same dsRNA technique to regulate their own
gene activity, by producing 'mirror image' messenger RNAs that bind to
the active gene's messenger RNA, forming a dsRNA complex - which is then
degraded.
The 'knockdown' technique differs from the knockout technique used to
silence genes in rodents, in that the DNA code of the original gene is
left unaltered - the silencing is performed at the gene-transcription stage.
CSIRO's vectors, which carry names like 'Hannibal', 'Kannibal' and
'Hellsgate' are essentially plug-and-play gene cassettes into which
geneticists can insert DNA sequences copied from the many messenger RNAs
of active genes in living cells.
The gene sequence, and the complementary DNA code from the non-gene
strand, are joined end-to-end, separated by a small sequence that forms a
hinge.
When the vector inserts the gene construct into living cells, the
transgene produces messenger RNAs that spontaneously fold back on
themselves, by complementary base-pairing, forming a hairpin shape.
The resulting dsRNA molecule is then detected by the cell, and destroyed
- an event that also programs the anti-viral mechanism to destroy the
'real' mRNAs from the targeted gene.
'The third great revolution' Benitec's director of research and
technology, Ken Reed, said yesterday the company was confident of its
patent position - "It's a great position to have. Mick Graham was the
first, by two and a half years, to demonstrate its efficacy in animal cells.
"It's the third revolution in biotechnology - first there was recombinant
DNA technology, then PCR, and now RNA interference," he said "We knew as
soon as the world woke up to the fact that it could be used in mammalian
cells, there would be the most massive brawl in relation to ownership of
the patent.
"In recent years, once companies realized its value, everyone has been
trawling back through their research in the early 1990s for anything that
might allow them to claim priority. It's bigger than Ben Hur."  
Source: http://www.gene.ch/genet/2003/Mar/msg00029.html
Finally, one needs to ask the question as to why, the C.S.I.R.O., the Q.D.P.I. and the Australian company Benitec dominate the RNAi patent landscape if they were simply contributors - remember with the USPTO works on 'first-to-invent' and not 'first-to-file basis.' Undoubtedly, Mello and Fire are great scientists, but the history and discovery section of this article is so narrow in its point of view that a better title might be - 'the life and times of Mello and Fire.'   
http://www.pi.csiro.au/RNAi/
HairpinRNAi – a CSIRO invention 
In 1995, CSIRO was first to recognise the role of double-stranded RNA as the trigger for gene silencing, now popularly known as “RNA Interference” or “RNAi”. 
When a plant with an antisense construct directed against a virus sequence was crossed with a plant containing a sense construct against the same sequence, only the progeny that acquired both sense and antisense constructs were immune to virus infection (Waterhouse et al., 1998). 
The key CSIRO invention was a construct with linked sense and antisense or inverted repeat sequences (Figure 1). When transcribed, a self complementary RNA is produced that forms a ‘hairpin’ structure by folding back on itself (Waterhouse et al., 1998). 
Hairpin RNA with a double-stranded ‘stem’ is a more effective trigger of RNAi than separate sense plus antisense RNAs (Figure 2). This was proved by using constructs containing sequences from a reporter gene (GUS) and a viral gene (Potato Virus Y).
Rodney214 (talk) 13:30, 20 January 2011 (UTC)
thread_title:  CSIRO in Australia Invented RNAi in 1995   

message: The lead contains:
;"This process is known to spread systemically throughout the organism despite initially limited molar concentrations of siRNA."
The text suggests that this applies to all organisms. Is this correct? It appears to be true for plants and Drosophila. I've qualified the statement by adding "In some organisms ..." Aa77zz (talk) 11:38, 25 November 2011 (UTC)
thread_title:  Systemic spread 

message: Especially for the keepers of the history sections: I attended an RNAi symposium in Cambridge in the early 2000s and at least one speaker mentioned that the first RNAi experiment that he was aware of was at Merck in the 1960s(?) or 1970s(?).  (The same speaker also mentioned the more well known petunia experiments from the 1990s.)  The Merck guys injected RNA into organisms (plants? mice? rats?) and ... I forget what effect they saw.  Was anybody else at that symposium besides me?  Does anyone have details of the Merck experiment and result?  Please excuse the sketchiness of this contribution.AdderUser (talk) 18:18, 16 September 2014 (UTC)
thread_title:  Merck and RNAi: History Q 

message: Substituted at 03:45, 30 April 2016 (UTC)
thread_title: Assessment comment

message: First, I am delighted to find out that the article published on one of my most interesting fields is "featured"!
In fact, it is truly well structured: clear table of contents and understandable leading overview.
I also appreciate the quality of figures and the citation of key references of the main contributions to the RNAi discoveries.
Yet, I would like to point some lacunae:
1. Regarding the figure of the petunias, its reference must be Napoli & Jorgensen (i.e. 162 not 160). And it's important to mention their names in the text.
2. Regarding the first sentence of the article, you saved yourselves by using the diplomatic adverb "typically". Despite this diplomacy, the sentence is still wrong: if the the gene expression (i.e. transcription into mRNA) is inhibited, then there is no more mRNA (upstream) to be destructed.
Therefore, to play it safe and cover all possible mechanisms of RNAi, I suggest to rephrase the first sentence as follows:
"RNA interference (RNAi) is a biological process in which RNA molecules inhibit gene expression or translation, by neutralizing targeted  mRNA molecules". This definition covers the possible actions of RNAi: in the nucleus before exit of mRNA to the cytoplasm, cleavage by RISC or blocking the access of ribosomes.
3. I would suggest to add an illustration of the experiment of Mello & Fire, which was central in the RNAi history, instead of simply showing a photo of C. elegans.
4. As for the mechanism of gene silencing, you missed a very crucial step: both miRNA and siRNA have two strands, sense and antisense. So, the major step before destruction by RISC is retaining the antisense and discarding the sense. RLC (RISC-Loading Complex) achieves this selection.
5. Mentioning "Argonaute" as the cleaving protein is braod; let's be more specific: its Argonaute 2 (Ago2)! Then, why was it named argonaute? I'm always interested in knowing and informing the readers about the nomenclatures and etymologies.
6. I would suggest to add some more therapeutic applications of RNAi beside viruses and cancer. By the way, either subtitle "viruses" and "cancers", or "antiviral" and "anti-cancerous", or "virology" and "oncology"!
7. I suggest adding a section about the delivery vehicles of RNAi.
Congratulations again for the quality of the article, especially on the level of organization! I'm available to participate in editing the article upon responses to my present evaluation.
Thanks!
Oucèma  — Preceding unsigned comment added by AboulOus (talk • contribs) 03:24, 28 October 2016 (UTC)
replies: text: Thanks for posting your thoughts! I was one of the people who brought this to "featured" status, and most of that work was done in 2006, with a push to get it up to scratch after the Nobel was announced, leading to an FA nomination in early 2007. Obviously there have been updates since, but other than a brief review in 2008 I don't think anyone has really systematically gone through to make sure everything is current and polish it up again. Sounds like you know the topic well, so go right ahead! You can post at the MCB or medicine project talk pages if you need help or want more feedback. Opabinia regalis (talk) 04:12, 28 October 2016 (UTC)
thread_title:  Additions regarding RNAi mechanism and therapeutic approaches 

message: Hi. A quote from the article: "For instance, in gastrointestinal cancers, nine miRNAs have been identified as epigenetically altered and effective in down regulating DNA repair enzymes." I believe that is an incorrect statement. I believe the correct statement should be:  "For instance, in gastrointestinal cancers, nine miRNA genes have been identified as epigenetically altered and thus cause effective down regulation of DNA repair enzymes". Am I mising something? I haven't read the reference and citations from it in excruciating detail, but I don't believe the miRNAs themselves are modified. Small point at the fringe of my knowledge, so I haven't made the change unless I get input. Thanks, DennisPietras (talk) 13:23, 18 January 2017 (UTC)
thread_title:  miRNAs epigenetically altered???? 

message: Seriously, do you understand the process of translation and how it differs from transcription? If you think you know something that I don't, please explain it here. DennisPietras (talk) 20:19, 24 January 2017 (UTC)
thread_title:  Translation 

message: I think that this page is quite good on RNAi but what concerns me is that "Regulatory RNA" sends me to this page.  RNA inhibition using the miRNAs is only one of the presently known kinds of RNA regulator-based systems that regulate gene expression at various levels.  miRNAs are usually but not always inhibitory of gene expression, acting post-transcriptionally by activating the degradation of mRNAs that match the miRNA, true.  
But there are other kinds of RNA that shut down transcription of blocks of chromatin, for example the Xist and Tsix and related molecules involved in X-inactivation for dosage compensation. Those are long noncoding RNAs (lncRNAs). The chromosome-wide inactivation of genes for transcription occurs via recruiting of polycomb complex.  It's an epigenetic regulator of inactive chromatin state.   
Enhancer RNAs might turn out to be a subset of the lncRNAs but some of them may be much shorter than the 200bp cutoff; in my view we haven't worked out enough systems regulated by enhancer RNAs to know.  But they involve regulation of one or a few genes controlled by the enhancer that is transcribed, not multi-gene blocks of chromatin.   I am planning to write an article for Wikipedia briefly summarizing the types of Regulatory RNA. It will connect to this article and the other relevant ones so that the strange cross reference won't have to occur.  Please let me know if this sounds counterproductive to you.LLMHoopes (talk) 10:03, 6 August 2018 (UTC)
replies: text: Long-delayed reaction, but eeek, you're right, regulatory RNA really shouldn't redirect here. Did you ever get around to writing that more general article (maybe under another title)? Opabinia regalis (talk) 22:50, 29 December 2018 (UTC)
thread_title:  Regulatory RNA is not only RNAi