Editing Polysome (section)

{{Short description|Ribosomes bound to an mRNA molecule}}
{{about|the term in cell biology|the term in crystallography|Polysome (crystallography)}}
[[File:Multiple Ribosomes Translation Protein Synthesis.png|thumb|Several ribosomes synthesizing a polypeptide on the same mRNA strand]]
A '''polyribosome''' (or '''polysome''' or '''ergosome''') is a group of ribosomes bound to an [[Messenger RNA|mRNA]] molecule like “beads” on a “thread”.<ref name=":0">{{cite journal | vauthors = Afonina ZA, Shirokov VA | title = Three-Dimensional Organization of Polyribosomes- A Modern Approach | journal = Biochemistry. Biokhimiia | volume = 83 | issue = Suppl 1 | pages = S48–S55 | date = January 2018 | pmid = 29544430 | doi = 10.1134/S0006297918140055 | s2cid = 3745602 }}</ref>  It consists of a complex of an mRNA molecule and two or more [[ribosome]]s that act to [[translation (biology)|translate]] [[mRNA]] instructions into [[polypeptide]]s. Originally coined "ergosomes" in 1963, they were further characterized by Jonathan Warner, Paul M. Knopf,<ref name="Cambra2017">{{cite web|last1=Cambra|first1=Kris | name-list-style = vanc |title=Paul M. Knopf, PhD|url=http://www.brownmedicinemagazine.org/blog/paul-m-knopf-phd/|website=Brown Medicine|publisher=[[Brown University]]|accessdate=24 July 2017|date=Spring 2017}}</ref> and [[Alex Rich]].

Polysomes are formed during the [[Eukaryotic_transcription#Elongation|elongation phase]] when ribosomes and elongation factors synthesize the encoded polypeptide. Multiple ribosomes move along the coding region of mRNA, creating a polysome. The ability of multiple ribosomes to function on an mRNA molecule explains the limited abundance of mRNA in the cell.<ref name=":1">{{cite journal | vauthors = King HA, Gerber AP | title = Translatome profiling: methods for genome-scale analysis of mRNA translation | journal = Briefings in Functional Genomics | volume = 15 | issue = 1 | pages = 22–31 | date = January 2016 | pmid = 25380596 | doi = 10.1093/bfgp/elu045 | doi-access = free }}</ref> Polyribosome structure differs between prokaryotic polysomes, eukaryotic polysomes, and membrane bound polysomes.<ref name=":0" /> Polysome activity can be used to measure the level of gene expression through a technique called polysomal profiling.<ref name=":2">{{cite journal | vauthors = Li S, Le B, Ma X, Li S, You C, Yu Y, Zhang B, Liu L, Gao L, Shi T, Zhao Y, Mo B, Cao X, Chen X | display-authors = 6 | title = Biogenesis of phased siRNAs on membrane-bound polysomes in Arabidopsis | journal = eLife | volume = 5 | pages = e22750 | date = December 2016 | pmid = 27938667 | pmc = 5207768 | doi = 10.7554/eLife.22750 | veditors = Qi J | doi-access = free }}</ref>