User:HaleeG/sandbox
Effects on gene expression
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During protein synthesis, rapidly changing conditions in the cell can cause ribosomal pausing. In bacteria, this can affect growth rate and trigger translational abandonment. This releases the ribosome from the mRNA and the incomplete polypeptide is targeted for destruction.[1]
In eukaryotes, ribosomal pausing can initiate an analogous process which triggers endonucleolytic attack of the mRNA, a process termed mRNA no-go decay. Ribosomal pausing also aids co-translational folding of the nascent polypeptide on the ribosome, and delays protein translation while its encoding mRNA; this can trigger ribosomal frameshifting.[1]
(Edited 3-4-20)
Protein synthesis must occur in a specific way for ribosomal pausing to impact or change the outcome of this process. The products that are made because of the ribosomal pausing can be broken down by Ribosome Quality Control (RQC). RQC can happen after the ribosomal pausing. Even though RQC works to undo the effects of the ribosomal pause, there are specific situations relating to proteins when the ribosomal pause is needed.[2] Ribosomal pausing does have an impact on the rate of protein synthesis and it may decrease the rate that it occurs. [3]
Advantage of the ribosomal pause
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When the ribosome movement on the mRNA is not linear, the ribosome gets paused at different regions without a precise reason. The ribosome pause position will help to identify the mRNA sequence features, structure, and the transacting factor that modulates this process.[4] The advantage of ribosomal pause sites that are located at protein domain boundaries are aiding the folding of a protein.[5]
(Edited 3-4-20)
There are times when the ribosomal pause does not cause an advantage and it needs to be restricted. In translation, elF5A inhibits ribosomal pausing for translation to function better. Ribosomal pausing can cause more non-canonical start codons without elF5A in eukaryotic cells. When there is a lack of elF5A in the eukaryotic cell, it can cause an increase in ribosomal pausing.[6] The ribosomal pausing process can also be used by amino acids to control translation. [3]
The location of the ribosome pause event in vitro
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It is known that ribosomes pause at distinct sites, but the reasons for these pauses are mostly unknown. Also, the ribosome pauses if the pseudoknot is disrupted. 10% of the ribosome pauses at the pseudoknot and 4% of the ribosomes are terminated. Before the ribosome is obstructed it passes the pseudoknot.[7] An assay was put together by a group from the University of California in an effort to show a model of mRNA. The translation was monitored in two in vitro systems. It was found that translating ribosomes aren't uniformly distributed along an mRNA.[8]
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Protein folding in vivo is also important and is related to protein synthesis. For finding the location of the ribosomal pause in vivo, the methods that have been used to find the ribosomal pause in vitro can be changed to find these specific locations in vivo.[9]
Ribosome Profiling
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Ribosome Profiling is a method that can reveal pausing sites through sequencing the ribosome protected fragments(RPFs or footprints) to map ribosome occupancy on the mRNA. Ribosome profiling has the ability to reveal the ribosome pause sites in the whole transcriptome. When the kinetics layer is added, it discloses the time of the pause, and the translation takes place.[10] Ribosome profling is however still in early stages and has biases that need to be explored further.[11]
(Edited 3-4-20)
Ribosome profiling allows for translation to be measured more accurately and precisely. During this process, translation needs to be stopped in order for ribosome profiling to be performed. This may cause a problem with ribosome profiling because the methods that are used to stop translation in an experiment can impact the outcome, which causes incorrect results. Ribosome profiling is useful for getting specific information on translation and the process of protein synthesis. Ribosome profiling has been used successfully in several recent studies. [12]
- ^ a b Buchan JR, Stansfield I (September 2007). "Halting a cellular production line: responses to ribosomal pausing during translation". Biology of the Cell. 99 (9): 475–487. doi:10.1042/BC20070037. PMID 17696878.
- ^ Ma, Collart; B, Weiss (2020-02-20). "Ribosome Pausing, a Dangerous Necessity for Co-Translational Events". Nucleic acids research. PMID 31598688. Retrieved 2020-03-03.
- ^ a b Darnell, Alicia M.; Subramaniam, Arvind R.; O’Shea, Erin K. (2018-07-19). "Translational Control through Differential Ribosome Pausing during Amino Acid Limitation in Mammalian Cells". Molecular Cell. 71 (2): 229–243.e11. doi:10.1016/j.molcel.2018.06.041. ISSN 1097-2765. PMID 30029003.
- ^ P, Wolin, S L Walter (November 1988). Ribosome pausing and stacking during translation of a eukaryotic mRNA. OCLC 678234823.
{{cite book}}: CS1 maint: multiple names: authors list (link) - ^ Gawroński, Piotr; Jensen, Poul Erik; Karpiński, Stanisław; Leister, Dario; Scharff, Lars B. (March 2018). "Pausing of Chloroplast Ribosomes Is Induced by Multiple Features and Is Linked to the Assembly of Photosynthetic Complexes1[OPEN]". Plant Physiology. 176 (3): 2557–2569. doi:10.1104/pp.17.01564. ISSN 0032-0889. PMC 5841727. PMID 29298822.
- ^ Manjunath, Hema; Zhang, He; Rehfeld, Frederick; Han, Jaeil; Chang, Tsung-Cheng; Mendell, Joshua T. (2019-12-03). "Suppression of Ribosomal Pausing by eIF5A Is Necessary to Maintain the Fidelity of Start Codon Selection". Cell reports. 29 (10): 3134–3146.e6. doi:10.1016/j.celrep.2019.10.129. ISSN 2211-1247. PMC 6917043. PMID 31801078.
- ^ Somogyi, P; Jenner, A J; Brierley, I; Inglis, S C (November 1993). "Ribosomal pausing during translation of an RNA pseudoknot". Molecular and Cellular Biology. 13 (11): 6931–6940. doi:10.1128/mcb.13.11.6931. ISSN 0270-7306. PMC 364755.
- ^ Wolin, S L; Walter, P (November 1988). "Ribosome pausing and stacking during translation of a eukaryotic mRNA". The EMBO Journal. 7 (11): 3559–3569. ISSN 0261-4189. PMID 2850168.
- ^ Ss, Jha; Aa, Komar (2012-07-06). "Isolation of Ribosome Bound Nascent Polypeptides in Vitro to Identify Translational Pause Sites Along mRNA". Journal of visualized experiments : JoVE. PMID 22806127. Retrieved 2020-03-03.
- ^ Brar, G. A.; Yassour, M.; Friedman, N.; Regev, A.; Ingolia, N. T.; Weissman, J. S. (2011-12-22). "High-Resolution View of the Yeast Meiotic Program Revealed by Ribosome Profiling". Science. 335 (6068): 552–557. doi:10.1126/science.1215110. ISSN 0036-8075. PMC 3414261. PMID 22194413.
- ^ Buskirk, Allen R.; Green, Rachel (2017-03-19). "Ribosome pausing, arrest and rescue in bacteria and eukaryotes". Philosophical Transactions of the Royal Society B: Biological Sciences. 372 (1716). doi:10.1098/rstb.2016.0183. ISSN 0962-8436. PMC 5311927. PMID 28138069.
- ^ Brar, Gloria A.; Weissman, Jonathan S. (2015-11). "Ribosome profiling reveals the what, when, where, and how of protein synthesis". Nature reviews. Molecular cell biology. 16 (11): 651–664. doi:10.1038/nrm4069. ISSN 1471-0072. PMC 5522010. PMID 26465719.
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