Editing Non-coding RNA (section)

{{Hatnote|Compare [[untranslated region]]s.}}
{{short description|Class of ribonucleic acid that is not translated into proteins}}
[[File:NcRNAs-central-dogma.svg|thumb|400x400px|The roles of non-coding RNAs: [[Ribonucleoprotein|Ribonucleoproteins]] are shown in red, non-coding RNAs in blue.]]
A '''non-coding RNA''' ('''ncRNA''') is a functional [[RNA]] molecule that is not [[Translation (genetics)|translated]] into a [[protein]]. The [[DNA]] sequence from which a functional non-coding RNA is transcribed is often called an RNA [[gene]]. Abundant and functionally important [[list of RNAs|types of non-coding RNAs]] include [[transfer RNA]]s (tRNAs) and [[ribosomal RNA]]s (rRNAs), as well as small RNAs such as [[microRNA]]s, [[siRNA]]s, [[piRNA]]s, [[snoRNA]]s, [[snRNA]]s, [[Extracellular RNA|exRNAs]], [[scaRNAs]] and the [[long noncoding RNA|long ncRNA]]s such as [[Xist]] and [[HOTAIR]].

The number of non-coding RNAs within the human genome is unknown; however, recent [[Transcriptomics|transcriptomic]] and [[Bioinformatics|bioinformatic]] studies suggest that there are thousands of non-coding transcripts.<ref name="pmid15790807">{{cite journal | vauthors = Cheng J, Kapranov P, Drenkow J, Dike S, Brubaker S, Patel S, Long J, Stern D, Tammana H, Helt G, Sementchenko V, Piccolboni A, Bekiranov S, Bailey DK, Ganesh M, Ghosh S, Bell I, Gerhard DS, Gingeras TR | display-authors = 6 | title = Transcriptional maps of 10 human chromosomes at 5-nucleotide resolution | journal = Science | volume = 308 | issue = 5725 | pages = 1149–1154 | date = May 2005 | pmid = 15790807 | doi = 10.1126/science.1108625 | s2cid = 13047538 | bibcode = 2005Sci...308.1149C }}</ref><ref name="pmid17571346" /><ref name="Thind">{{cite journal | vauthors = Thind AS, Monga I, Thakur PK, Kumari P, Dindhoria K, Krzak M, Ranson M, Ashford B | display-authors = 6 | title = Demystifying emerging bulk RNA-Seq applications: the application and utility of bioinformatic methodology | journal = Briefings in Bioinformatics | volume = 22 | issue = 6 | date = November 2021 | pmid = 34329375 | doi = 10.1093/bib/bbab259 }}</ref><ref name="pmid17568003">{{cite journal | vauthors = Washietl S, Pedersen JS, Korbel JO, Stocsits C, Gruber AR, Hackermüller J, Hertel J, Lindemeyer M, Reiche K, Tanzer A, Ucla C, Wyss C, Antonarakis SE, Denoeud F, Lagarde J, Drenkow J, Kapranov P, Gingeras TR, Guigó R, Snyder M, Gerstein MB, Reymond A, Hofacker IL, Stadler PF | display-authors = 6 | title = Structured RNAs in the ENCODE selected regions of the human genome | journal = Genome Research | volume = 17 | issue = 6 | pages = 852–864 | date = June 2007 | pmid = 17568003 | pmc = 1891344 | doi = 10.1101/gr.5650707 }}</ref><ref name= MorrisKV>{{cite book | veditors = Morris KV | year=2012 | title=Non-coding RNAs and Epigenetic Regulation of Gene Expression: Drivers of Natural Selection | publisher=[[Caister Academic Press]] | isbn= 978-1-904455-94-3}}</ref><ref name="Shahrouki P 2012">{{cite journal | vauthors = Shahrouki P, Larsson E | title = The non-coding oncogene: a case of missing DNA evidence? | journal = Frontiers in Genetics | volume = 3 | pages = 170 | date = 2012 | pmid = 22988449 | pmc = 3439828 | doi = 10.3389/fgene.2012.00170 | doi-access = free }}</ref><!--<sup> but see </sup>--><ref>{{cite journal | vauthors = van Bakel H, Nislow C, Blencowe BJ, Hughes TR | title = Most "dark matter" transcripts are associated with known genes | journal = PLOS Biology | volume = 8 | issue = 5 | pages = e1000371 | date = May 2010 | pmid = 20502517 | pmc = 2872640 | doi = 10.1371/journal.pbio.1000371 | veditors = Eddy SR | doi-access = free }}</ref> 
Many of the newly identified ncRNAs have unknown functions, if any.<ref name="pmid15851066">{{cite journal | vauthors = Hüttenhofer A, Schattner P, Polacek N | title = Non-coding RNAs: hope or hype? | journal = Trends in Genetics | volume = 21 | issue = 5 | pages = 289–297 | date = May 2005 | pmid = 15851066 | doi = 10.1016/j.tig.2005.03.007 }}</ref> 
There is no consensus on how much of non-coding transcription is functional: some believe most ncRNAs to be non-functional "junk RNA", spurious transcriptions,<ref name="waste">{{cite journal | vauthors = Brosius J | title = Waste not, want not--transcript excess in multicellular eukaryotes | journal = Trends in Genetics | volume = 21 | issue = 5 | pages = 287–288 | date = May 2005 | pmid = 15851065 | doi = 10.1016/j.tig.2005.02.014 }}</ref><ref name="PalazzoLee2015">{{cite journal | vauthors = Palazzo AF, Lee ES | title = Non-coding RNA: what is functional and what is junk? | journal = Frontiers in Genetics | volume = 6 | pages = 2 | year = 2015 | pmid = 25674102 | pmc = 4306305 | doi = 10.3389/fgene.2015.00002 | doi-access = free }}</ref> while others expect that many non-coding transcripts have functions to be discovered.<ref>{{cite book | vauthors = Mattick J, Amaral P |title=RNA, The Epicenter of Genetic Information : A New Understanding of Molecular Biology |date=2022 |publisher=CRC Press |isbn= 9780367623920}}</ref><ref>{{cite journal | vauthors = Lee H, Zhang Z, Krause HM | title = Long Noncoding RNAs and Repetitive Elements: Junk or Intimate Evolutionary Partners? | journal = Trends in Genetics | volume = 35 | issue = 12 | pages = 892–902 | date = December 2019 | pmid = 31662190 | doi = 10.1016/j.tig.2019.09.006 | s2cid = 204975291 | doi-access = free }}</ref>