Editing Gene expression (section)

===Translation===
{{main|Translation (biology)}}
For some non-coding RNA, the mature RNA is the final gene product.<ref name="Amaral2008">{{cite journal | vauthors = Amaral PP, Dinger ME, Mercer TR, Mattick JS | title = The eukaryotic genome as an RNA machine | journal = Science | volume = 319 | issue = 5871 | pages = 1787–1789 | date = March 2008 | pmid = 18369136 | doi = 10.1126/science.1155472 | s2cid = 206511756 | bibcode = 2008Sci...319.1787A }}</ref> In the case of messenger RNA (mRNA) the RNA is an information carrier coding for the synthesis of one or more proteins. mRNA carrying a single protein sequence (common in eukaryotes) is [[monocistronic]] whilst mRNA carrying multiple protein sequences (common in prokaryotes) is known as [[polycistronic]].

[[File:Ribosome mRNA translation en.svg|300px|thumb|right|alt=Ribosome translating messenger RNA to chain of amino acids (protein).|During the translation, tRNA charged with amino acid enters the ribosome and aligns with the correct mRNA triplet. Ribosome then adds amino acid to growing protein chain.]]
Every mRNA consists of three parts: a 5′ untranslated region (5′UTR), a protein-coding region or [[open reading frame]] (ORF), and a 3′ untranslated region (3′UTR). The coding region carries information for protein synthesis encoded by the [[genetic code]] to form triplets. Each triplet of nucleotides of the [[coding region]] is called a [[codon]] and corresponds to a binding site complementary to an anticodon triplet in transfer RNA. Transfer RNAs with the same anticodon sequence always carry an identical type of [[amino acid]]. Amino acids are then chained together by the [[ribosome]] according to the order of triplets in the coding region. The ribosome helps transfer RNA to bind to messenger RNA and takes the amino acid from each transfer RNA and makes a structure-less protein out of it.<ref name="Hansen2003">{{cite journal | vauthors = Hansen TM, Baranov PV, Ivanov IP, Gesteland RF, Atkins JF | title = Maintenance of the correct open reading frame by the ribosome | journal = EMBO Reports | volume = 4 | issue = 5 | pages = 499–504 | date = May 2003 | pmid = 12717454 | pmc = 1319180 | doi = 10.1038/sj.embor.embor825 }}</ref><ref name="Berk2007">{{cite journal | vauthors = Berk V, Cate JH | title = Insights into protein biosynthesis from structures of bacterial ribosomes | journal = Current Opinion in Structural Biology | volume = 17 | issue = 3 | pages = 302–309 | date = June 2007 | pmid = 17574829 | doi = 10.1016/j.sbi.2007.05.009 }}</ref> Each mRNA molecule is translated into many protein molecules, on average ~2800 in mammals.<ref>{{cite journal | vauthors = Schwanhäusser B, Busse D, Li N, Dittmar G, Schuchhardt J, Wolf J, Chen W, Selbach M | title = Global quantification of mammalian gene expression control | journal = Nature | volume = 473 | issue = 7347 | pages = 337–342 | date = May 2011 | pmid = 21593866 | doi = 10.1038/nature10098 | s2cid = 205224972 | bibcode = 2011Natur.473..337S | url = http://edoc.mdc-berlin.de/11664/1/11664oa.pdf }}</ref><ref name="Schwanhaeusser2011">{{cite journal | vauthors = Schwanhäusser B, Busse D, Li N, Dittmar G, Schuchhardt J, Wolf J, Chen W, Selbach M | title = Corrigendum: Global quantification of mammalian gene expression control | journal = Nature | volume = 495 | issue = 7439 | pages = 126–127 | date = March 2013 | pmid = 23407496 | doi = 10.1038/nature11848 | doi-access = free | bibcode = 2013Natur.495..126S }}</ref>

In prokaryotes translation generally occurs at the point of transcription (co-transcriptionally), often using a messenger RNA that is still in the process of being created. In eukaryotes translation can occur in a variety of regions of the cell depending on where the protein being written is supposed to be. Major locations are the [[cytoplasm]] for soluble cytoplasmic proteins and the membrane of the [[endoplasmic reticulum]] for proteins that are for export from the cell or insertion into a cell [[lipid bilayer|membrane]]. Proteins that are supposed to be produced at the endoplasmic reticulum are recognised part-way through the translation process. This is governed by the [[signal recognition particle]]—a protein that binds to the ribosome and directs it to the endoplasmic reticulum when it finds a [[signal peptide]] on the growing (nascent) amino acid chain.<ref name="Hegde2008">{{cite journal | vauthors = Hegde RS, Kang SW | title = The concept of translocational regulation | journal = The Journal of Cell Biology | volume = 182 | issue = 2 | pages = 225–232 | date = July 2008 | pmid = 18644895 | pmc = 2483521 | doi = 10.1083/jcb.200804157 }}</ref>