Editing RNA (section)

==RNA in genetics==
===RNA genomes===
Like DNA, RNA can carry genetic information. [[RNA virus]]es have [[genome]]s composed of RNA that encodes a number of proteins. The viral genome is replicated by some of those proteins, while other proteins protect the genome as the virus particle moves to a new host cell. [[Viroid]]s are another group of pathogens, but they consist only of RNA, do not encode any protein and are replicated by a host plant cell's polymerase.<ref>{{cite journal | vauthors = Daròs JA, Elena SF, Flores R | title = Viroids: an Ariadne's thread into the RNA labyrinth | journal = EMBO Reports | volume = 7 | issue = 6 | pages = 593–98 | date = June 2006 | pmid = 16741503 | pmc = 1479586 | doi = 10.1038/sj.embor.7400706 }}</ref>

===Reverse transcription===
Reverse transcribing viruses replicate their genomes by [[Reverse transcription|reverse transcribing]] DNA copies from their RNA; these DNA copies are then transcribed to new RNA. [[Retrotransposon]]s also spread by copying DNA and RNA from one another,<ref>{{cite journal | vauthors = Kalendar R, Vicient CM, Peleg O, Anamthawat-Jonsson K, Bolshoy A, Schulman AH | title = Large retrotransposon derivatives: abundant, conserved but nonautonomous retroelements of barley and related genomes | journal = Genetics | volume = 166 | issue = 3 | pages = 1437–50 | date = March 2004 | pmid = 15082561 | pmc = 1470764 | doi = 10.1534/genetics.166.3.1437 }}</ref> and [[telomerase]] contains an [[Telomerase RNA component|RNA that is used as template]] for building the ends of [[Eukaryotic chromosome structure|eukaryotic chromosomes]].<ref>{{cite journal | vauthors = Podlevsky JD, Bley CJ, Omana RV, Qi X, Chen JJ | title = The telomerase database | journal = Nucleic Acids Research | volume = 36 | issue = Database issue | pages = D339–43 | date = January 2008 | pmid = 18073191 | pmc = 2238860 | doi = 10.1093/nar/gkm700 }}</ref>

=== Double-stranded RNA ===
[[File:Double-stranded RNA.gif|thumb|Double-stranded RNA]]{{Main articles|Double-stranded RNA}}
[[Double-stranded RNA]] (dsRNA) is RNA with two complementary strands, similar to the DNA found in all cells, but with the replacement of thymine by uracil and the adding of one oxygen atom. dsRNA forms the genetic material of some [[virus]]es ([[double-stranded RNA viruses]]). Double-stranded RNA, such as viral RNA or [[siRNA]], can trigger [[RNA interference]] in [[eukaryote]]s, as well as [[interferon]] response in [[vertebrate]]s.<ref>{{cite journal | vauthors = Blevins T, Rajeswaran R, Shivaprasad PV, Beknazariants D, Si-Ammour A, Park HS, Vazquez F, Robertson D, Meins F, Hohn T, Pooggin MM | title = Four plant Dicers mediate viral small RNA biogenesis and DNA virus induced silencing | journal = Nucleic Acids Research | volume = 34 | issue = 21 | pages = 6233–46 | date = 2006 | pmid = 17090584 | pmc = 1669714 | doi = 10.1093/nar/gkl886 }}
</ref><ref>{{cite journal | vauthors = Jana S, Chakraborty C, Nandi S, Deb JK | title = RNA interference: potential therapeutic targets | journal = Applied Microbiology and Biotechnology | volume = 65 | issue = 6 | pages = 649–57 | date = November 2004 | pmid = 15372214 | doi = 10.1007/s00253-004-1732-1 | s2cid = 20963666 }}</ref><ref>{{cite journal |last=Virol |first=J |date=May 2006 |title=Double-Stranded RNA Is Produced by Positive-Strand RNA Viruses and DNA Viruses but Not in Detectable Amounts by Negative-Strand RNA Viruses |journal=Journal of Virology |volume=80 |issue=10 |pages=5059–5064 |doi=10.1128/JVI.80.10.5059-5064.2006 |pmid=16641297 |pmc=1472073 }}</ref><ref>{{cite journal | vauthors = Schultz U, Kaspers B, Staeheli P | title = The interferon system of non-mammalian vertebrates | journal = Developmental and Comparative Immunology | volume = 28 | issue = 5 | pages = 499–508 | date = May 2004 | pmid = 15062646 | doi = 10.1016/j.dci.2003.09.009 }}</ref> In eukaryotes, double-stranded RNA (dsRNA) plays a role in the activation of the [[innate immune system]] against viral infections.<ref>{{cite journal | vauthors = Whitehead KA, Dahlman JE, Langer RS, Anderson DG | title = Silencing or stimulation? siRNA delivery and the immune system | journal = Annual Review of Chemical and Biomolecular Engineering | volume = 2 | pages = 77–96 | year = 2011 | pmid = 22432611 | doi = 10.1146/annurev-chembioeng-061010-114133 }}</ref>

=== Circular RNA ===
{{main|Circular RNA}}

In the late 1970s, it was shown that there is a single stranded covalently closed, i.e. circular form of RNA expressed throughout the animal and plant kingdom (see [[Circular RNA|circRNA]]).<ref>{{cite journal | vauthors = Hsu MT, Coca-Prados M | title = Electron microscopic evidence for the circular form of RNA in the cytoplasm of eukaryotic cells | language = En | journal = Nature | volume = 280 | issue = 5720 | pages = 339–40 | date = July 1979 | pmid = 460409 | doi = 10.1038/280339a0 | bibcode = 1979Natur.280..339H | s2cid = 19968869 }}</ref> circRNAs are thought to arise via a "back-splice" reaction where the [[spliceosome]] joins a upstream 3' acceptor to a downstream 5' donor splice site. So far the function of circRNAs is largely unknown, although for few examples a microRNA sponging activity has been demonstrated.