Global InformationBacterial transcription information
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Bacterial transcription is the process in which a segment of bacterial DNA is copied into a newly synthesized strand of messenger RNA (mRNA) with use of the enzyme RNA polymerase.
The process occurs in three main steps: initiation, elongation, and termination; and the end result is a strand of mRNA that is complementary to a single strand of DNA. Generally, the transcribed region accounts for more than one gene.[1] In fact, many prokaryotic genes occur in operons, which are a series of genes that work together to code for the same protein or gene product and are controlled by a single promoter.[2] Bacterial RNA polymerase is made up of four subunits and when a fifth subunit attaches, called the sigma factor (σ-factor), the polymerase can recognize specific binding sequences in the DNA, called promoters.[3] The binding of the σ-factor to the promoter is the first step in initiation. Once the σ-factor releases from the polymerase, elongation proceeds.[4] The polymerase continues down the double stranded DNA, unwinding it and synthesizing the new mRNA strand until it reaches a termination site. There are two termination mechanisms that are discussed in further detail below. Termination is required at specific sites for proper gene expression to occur.[5] Gene expression determines how much gene product, such as protein, is made by the gene.[2] Transcription is carried out by RNA polymerase but its specificity is controlled by sequence-specific DNA binding proteins called transcription factors. Transcription factors work to recognize specific DNA sequences and based on the cells needs, promote or inhibit additional transcription.[6] Similar to other taxa, bacteria experience bursts of transcription.[7]: 125 [8][9][10][11][12][13] The work of the Jones team in Jones et al 2014 explains some of the underlying causes of bursts and other variability, including stability of the resulting mRNA,[7]: 125 the strength of promotion encoded in the relevant promoter[9] and the duration of transcription due to strength of the TF binding site.[9][10][11][12][13] They also found that bacterial TFs linger too briefly for TFs' binding characteristics to explain the sustained transcription of bursts.[8]
Bacterial transcription differs from eukaryotic transcription in several ways. In bacteria, transcription and translation can occur simultaneously in the cytoplasm of the cell, whereas in eukaryotes transcription occurs in the nucleus and translation occurs in the cytoplasm.[14] There is only one type of bacterial RNA polymerase whereas eukaryotes have 3 types.[2] Bacteria have a σ-factor that detects and binds to promoter sites but eukaryotes do not need a σ-factor. Instead, eukaryotes have transcription factors that allow the recognition and binding of promoter sites.[2]
Overall, transcription within bacteria is a highly regulated process that is controlled by the integration of many signals at a given time. Bacteria heavily rely on transcription and translation to generate proteins that help them respond specifically to their environment.[4]
- ^ "Prokaryotic Transcription and Translation | Biology for Majors I". courses.lumenlearning.com. Retrieved 2019-10-06.
- ^ a b c d Alberts B, Johnson A, Lewis J, Raff M, Roberts K, Walter P (2008). Molecular Biology of the Cell (Sixth ed.). New York: Garland Science. ISBN 978-0-8153-4524-4.
- ^ Bartee L (2017). Prokaryotic Transcription. Open Oregon Educational Resources. Retrieved 2019-10-08.
{{cite book}}:|work=ignored (help) - ^ a b Lodish H, Berk A, Zipursky SL, Matsudaira P, Baltimore D, Darnel l J (2000). "Bacterial Transcription Initiation". Molecular Cell Biology (4th ed.).
- ^ "Stages of transcription". Khan Academy. Retrieved 2019-10-07.
- ^ Browning DF, Butala M, Busby SJ (September 2019). "Bacterial Transcription Factors: Regulation by Pick "N" Mix". Journal of Molecular Biology. 431 (20): 4067–4077. doi:10.1016/j.jmb.2019.04.011. PMID 30998934.
- ^ a b El-Mansi, E. M. T.; Nielsen, Jens; Mousdale, David; Allman, Tony; Carlson, Ross (2019). El-Mansi, Mansi; Nielsen, Jens; Mousdale, David M.; Allman, Tony; Carlson, Ross (eds.). Fermentation Microbiology and Biotechnology (4 ed.). Boca Raton: CRC Press. pp. xix+419. doi:10.1201/9780429506987. ISBN 978-1-138-58102-9. OCLC 1080190329. S2CID 220766937. ISBN 978-0-429-50698-7.
- ^ a b Symmons, Orsolya; Raj, Arjun (2016). "What's Luck Got to Do with It: Single Cells, Multiple Fates, and Biological Nondeterminism". Molecular Cell. 62 (5). Cell Press: 788–802. doi:10.1016/j.molcel.2016.05.023. ISSN 1097-2765. PMC 4900469. PMID 27259209.
- ^ a b c Payne, Joshua L.; Wagner, Andreas (2018-11-01). "The causes of evolvability and their evolution" (PDF). Nature Reviews Genetics. 20 (1). Nature Portfolio: 24–38. doi:10.1038/s41576-018-0069-z. ISSN 1471-0056. PMID 30385867. S2CID 53204518.
- ^ a b Typas, Athanasios; Sourjik, Victor (2015-08-10). "Bacterial protein networks: properties and functions". Nature Reviews Microbiology. 13 (9). Nature Portfolio: 559–572. doi:10.1038/nrmicro3508. ISSN 1740-1526. PMID 26256789. S2CID 12498094.
- ^ a b Bashor, Caleb J.; Collins, James J. (2018-05-20). "Understanding Biological Regulation Through Synthetic Biology". Annual Review of Biophysics. 47 (1). Annual Reviews: 399–423. doi:10.1146/annurev-biophys-070816-033903. hdl:1721.1/119222. ISSN 1936-122X. PMID 29547341. S2CID 3888755.
- ^ a b Xu, Heng; Skinner, Samuel O.; Sokac, Anna Marie; Golding, Ido (2016-09-13). "Stochastic Kinetics of Nascent RNA". Physical Review Letters. 117 (12). American Physical Society: 128101. Bibcode:2016PhRvL.117l8101X. doi:10.1103/physrevlett.117.128101. ISSN 0031-9007. PMC 5033037. PMID 27667861. NIHMS 816487.
- ^ a b Eling, Nils; Morgan, Michael D.; Marioni, John C. (2019-05-21). "Challenges in measuring and understanding biological noise". Nature Reviews Genetics. 20 (9). Nature Portfolio: 536–548. doi:10.1038/s41576-019-0130-6. ISSN 1471-0056. PMC 7611518. PMID 31114032. EMSID: 85286
- ^ "15.2: Prokaryotic Transcription". General Biology (OpenStax). LibreTexts. 2015-11-02. Retrieved 2019-10-08.