User:Jordan Scott/Sandbox RNA polII: Difference between revisions
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[[ Image:Label RNA pol II (1).png|150px|right|thumb| RNAP II transcription process.]] | [[ Image:Label RNA pol II (1).png|150px|right|thumb| RNAP II transcription process.]] | ||
RNA Polymerases (RNAPs) are a group of enzymes that synthesize RNA in a process called transcription. During transcription the polymerase reads the DNA template strand and produces a RNA strand complementary to the template strand. The nascent RNA matches the DNA coding strand. Transcription can be divided into three processes that are discussed below: initiation, elongation and termination. Transcription in eukaryotes requires more distinct proteins for effective control. We see this as prokaryotic organisms have one core polymerase that synthesizes all of their RNA. However, eukaryotes have three distinct RNAPs named RNAP I, II, and III. RNAP I synthesizes rRNA precursors and RNAP III makes tRNA and the 5s rRNA. (A) | |||
RNAP II is responsible for the synthesis of pre-mRNA and snRNs. It is 550 kDa and made of 12 subunits that range from 220-10 kDa. The subunits are highly conserved to the point that mammalian subunits can substitute with yeast subunits are there are little to no defects.(B0) There are two large sub units t and 10 smaller subunits, some of which are shared with RNAPs I and III. While RNAP II is capable of transcription by itself it is non-selective of any particular DNA region. However some mutageneis studies have shown that RNAP II may have some role in selectivity. (A) To properly recognize regions upstream of the gene's transcription start site it requires several general transcription factors that are selective for these regions known as promoters and positions RNAP to accurately begin transcription. (B) These GTF's and other accessriy proteins called SRBs are neccesary for accurate transcription and togetther with teh RNAP II core enzyme form the holoenzyme. | |||
'''RNA polymerase II''' (RNAP II) is an enzyme that transcribes protein-encoding genes, and it therefore is responsible for the synthesis of mRNA. There are three RNA polymerase enzymes found in eukaryotic nuclei but RNAP II is the most studied. RNAP II is a 550 kDa multi-protein complex that includes 12 subunits. Several transcription factors are used to bind promoters upstream of the start site and are necessary for joining RNAP II and DNA. Bound RNAP II transcribes DNA into a strand of messenger RNA (mRNA). mRNA is a single stranded RNA molecule that is complementary to the template strand of DNA and matches the coding strand. In prokaryotes the transcript is ready for translation, but in eukaryotes post transcriptional modifications are required. The mRNA stand transports genetic information from DNA to the ribosome,where the code will be translated into an amino acid acid sequence to form proteins. | '''RNA polymerase II''' (RNAP II) is an enzyme that transcribes protein-encoding genes, and it therefore is responsible for the synthesis of mRNA. There are three RNA polymerase enzymes found in eukaryotic nuclei but RNAP II is the most studied. RNAP II is a 550 kDa multi-protein complex that includes 12 subunits. Several transcription factors are used to bind promoters upstream of the start site and are necessary for joining RNAP II and DNA. Bound RNAP II transcribes DNA into a strand of messenger RNA (mRNA). mRNA is a single stranded RNA molecule that is complementary to the template strand of DNA and matches the coding strand. In prokaryotes the transcript is ready for translation, but in eukaryotes post transcriptional modifications are required. The mRNA stand transports genetic information from DNA to the ribosome,where the code will be translated into an amino acid acid sequence to form proteins. | ||
===Subunits=== | |||
The 12 subunits that make up | |||
===History=== | ===History=== | ||
The Discovery and Isolation of RNA Polymerase by Jerard Hurwitz | The Discovery and Isolation of RNA Polymerase by Jerard Hurwitz | ||
== Structural Components == | == Structural Components == | ||
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Process of PIC formation: | Process of PIC formation: | ||
https://www.rcsb.org/structure/5VVS Use this for scene making | |||
Source: https://www.pnas.org/content/94/1/151. | Source: https://www.pnas.org/content/94/1/151. | ||
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4. <scene name='82/824648/Tfiie/4'>TFIIE</scene> and <scene name='82/824648/Tfiih/3'>TFIIH</scene> are sequentially recruited which completes the <scene name='82/824648/Pic/3'>PIC</scene>. | 4. <scene name='82/824648/Tfiie/4'>TFIIE</scene> and <scene name='82/824648/Tfiih/3'>TFIIH</scene> are sequentially recruited which completes the <scene name='82/824648/Pic/3'>PIC</scene>. | ||
5.<scene name='82/824648/Tfiia/3'>TFIIA</scene> is a co-activator that helps regulate PIC assembly. It serves as an enhancer and stabilizes the early complexes. It allows for inhibitory effect to be reduced and activators to be more effective. | 5.<scene name='82/824648/Tfiia/3'>TFIIA</scene> is a co-activator that helps regulate PIC assembly. It was initially thought to be essential for activity. It serves as an enhancer and stabilizes the early complexes. It allows for inhibitory effect to be reduced and activators to be more effective. | ||
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</StructureSection> | </StructureSection> | ||
== References == | == References == | ||
(A)Young, Richard A. (2003-11-28). "RNA Polymerase II". Annual Review of Biochemistry. 60 (1): 689–715. doi:10.1146/annurev.bi.60.070191.003353. PMID 1883205. | |||
(B) https://www.jbc.org/content/273/43/27757 RNA Polymerase II Holoenzymes and Subcomplexes | |||
(C) RNA polymerase II transcription initiation: A structural view | |||
(D)The Discovery and Isolation of RNA Polymerase by Jerard Hurwitz | |||
Bushnell, D. A.; Westover, K. D.; Davis, R. E.; Kornberg, R. D. Structural Basis of Transcription: An RNA Polymerase II-TFIIB Cocrystal at 4.5 Angstroms. Science. 2004, 303, 983-988 | Bushnell, D. A.; Westover, K. D.; Davis, R. E.; Kornberg, R. D. Structural Basis of Transcription: An RNA Polymerase II-TFIIB Cocrystal at 4.5 Angstroms. Science. 2004, 303, 983-988 | ||
