RNA polimerasi eucariotiche RNA polymerases RNA polymerase I
- Slides: 50
RNA polimerasi eucariotiche
RNA polymerases ¨ RNA polymerase I synthesizes r. RNA in the nucleolus. ¨ RNA polymerase II synthesizes m. RNA in the nucleoplasm. ¨ RNA polymerase III synthesizes small RNAs in the nucleoplasm. ¨ All eukaryotic RNA polymerases have ~12 subunits and are aggregates of >500 k. D. ¨ Some subunits are common to all three RNA polymerases. ¨ The largest subunit in RNA polymerase II has a CTD (carboxyterminal domain) consisting of multiple repeats of an eptamer.
Promotori della pol III U 6
Watson et al. , BIOLOGIA MOLECOLARE DEL GENE, Zanichelli editore S. p. A. Copyright © 2005
Watson et al. , BIOLOGIA MOLECOLARE DEL GENE, Zanichelli editore S. p. A. Copyright © 2005
Promotori di tipo 3
I geni per gli r. RNA sono ripetuti in tandem nei genomi eucariotici NTS ETS 18 S 28 S ITS RNA DNA DNA other repetitive elements 60/81 bp repeats spacer promoter gene promoter
I precursori degli r. RNA sono piu' lunghi della somma degli r. RNA maturi
r. RNA genes ¨ Ribosomal RNA is coded by a large number of identical genes that are tandemly repeated to form a cluster(s). ¨ Each r. DNA cluster is organized so that transcription units giving a joint precursor to the major r. RNAs alternate with nontranscribed spacers.
Watson et al. , BIOLOGIA MOLECOLARE DEL GENE, Zanichelli editore S. p. A. Copyright © 2005
Il complesso d'inizio della pol I
Il complesso d'inizio della pol I • UBF: inizio, allungamento • SL 1: inizio • TIF-1 A (RRN 3): inizio • TTF-1: terminazione
Regolazione della sintesi dell'r. RNA
Regolazione della sintesi dell'r. RNA
Farmaci chemioterapici che inibiscono la sintesi dell'r. RNA
Il promotore minimo della pol II Watson et al. , BIOLOGIA MOLECOLARE DEL GENE, Zanichelli editore S. p. A. Copyright © 2005
Watson et al. , BIOLOGIA MOLECOLARE DEL GENE, Zanichelli editore S. p. A. Copyright © 2005
Gene reporter
Watson et al. , BIOLOGIA MOLECOLARE DEL GENE, Zanichelli editore S. p. A. Copyright © 2005
I promotori eucariotici sono costituiti da una associazione variabile di “box” -140 -120 -100 -80 -60 SV 40 (promotore precoce) Timidina kinasi Istone H 2 B Ottamero CAAT GC -40 -20 1 10
Attivatori costitutivi Modulo Attivatore DNA occupato Consenso Distribuzione CAAT box CTF/NF 1 22 bp GGCCAATCT ubiquitaria GC box SP 1 20 bp GGGCGG ubiquitaria Ottamero Oct-1 20 bp ATTGCAT ubiquitaria Ottamero Oct-2 23 bp ATTGCAT linfoidi k. B NFk. B 10 bp GGGACTTTCC ubiquitaria ATF 20 bp GTGACGT ubiquitaria
Attivatori inducibili e elementi di risposta Agente regolatore Elemento di risposta Consenso Fattore Dimensioni (dalton) Shock termico HSE CNNGCCNNTCCNNG HSTF 93. 000 Glucocorticoidi GRE TGGTACAAATGTTCT GR 94. 000 Cadmio MRE CGNCCCGGNCNC TPA TRE TGACTCA AP 1 39. 000 Siero SRE CCATATTAGG SRF 52. 000
Esempio di promotore
Watson et al. , BIOLOGIA MOLECOLARE DEL GENE, Zanichelli editore S. p. A. Copyright © 2005
Watson et al. , BIOLOGIA MOLECOLARE DEL GENE, Zanichelli editore S. p. A. Copyright © 2005
Enhancers § Similar sequence elements are found in enhancers and promoters. § Enhancers form complexes of transcription factors that interact directly or indirectly with the promoter.
Watson et al. , BIOLOGIA MOLECOLARE DEL GENE, Zanichelli editore S. p. A. Copyright © 2005
Watson et al. , BIOLOGIA MOLECOLARE DEL GENE, Zanichelli editore S. p. A. Copyright © 2005
Watson et al. , BIOLOGIA MOLECOLARE DEL GENE, Zanichelli editore S. p. A. Copyright © 2005
Ruolo degli Isolatori
Watson et al. , BIOLOGIA MOLECOLARE DEL GENE, Zanichelli editore S. p. A. Copyright © 2005
Watson et al. , BIOLOGIA MOLECOLARE DEL GENE, Zanichelli editore S. p. A. Copyright © 2005
Watson et al. , BIOLOGIA MOLECOLARE DEL GENE, Zanichelli editore S. p. A. Copyright © 2005
LCR and insulators § An LCR is located at the 5 end of the domain and consists of several hypersensitive sites. § Insulators are specialized chromatin structures that have hypersensitive sites. § All known insulators are able to block passage of any activating or inactivating effects from enhancers, silencers, or LCRs. § In some cases, insulators have directionality, and may stop passage of effects in one direction but not the other.
Fattori di trascrizione negli eucarioti (trans-acting factors = fattori che agiscono in trans ) Possono essere distinti in: - Fattori generali - Fattori specifici (attivatori)
Complesso di inizio su un promotore Pol II 1 TBP + vari TAF -5 0 -4 0 -3 0 -2 0 TATA TFII D TATA TFII B TFIIF Pol II TFII E Pol -1 0 1 10 20
Watson et al. , BIOLOGIA MOLECOLARE DEL GENE, Zanichelli editore S. p. A. Copyright © 2005
Lewin, IL GENE VIII, Zanichelli editore S. p. A. Copyright © 2006
Attivazione della trascrizione
Lewin, IL GENE VIII, Zanichelli editore S. p. A. Copyright © 2006
Initiation at pol II promoters ¨ Binding of TFIID to the TATA box is the first step in initiation. ¨ Other transcription factors bind to the complex in a defined order, extending the length of the protected region on DNA. ¨ When RNA polymerase II binds to the complex, it initiates transcription.
Later events of pol II initiation ¨ TFIIE and TFIIH are required to melt DNA to allow polymerase movement. ¨ Phosphorylation of the CTD may be required for elongation to begin. ¨ Further phosphorylation of the CTD is required at some promoters to end abortive initiation. ¨ The CTD may coordinate processing of RNA with transcription.
Complessi basali delle RNA polimerasi eucariotiche
- Rna polimerasi
- Splicing alternativo
- Differenze trascrizione eucarioti e procarioti
- Cellule eucariotiche
- Rna polymerase 1 2 3
- Rho independent termination
- Rna polymerase
- Polimerasi theta
- The three steps of polymerase chain reaction
- Site:slidetodoc.com
- Dna prokaryot
- Taq dna polymerase
- Dna polymerase
- Types of dna polymerase in eukaryotes
- The principal enzyme involved in dna replication is
- Polymerase chain reaction uses
- Function of dna polymerase 3
- Dna polymerase
- Corbett maths
- Application pcr
- Template strand, new strand, base pair, and dna polymerase.
- Clonaggio
- Dna polymerase
- Dna replication eukaryotes
- Polymerase chain reaction
- Polymerase chain reaction
- Lagging strand
- Adn polymérase
- Polymerase chain reaction
- Transcription
- Lipidos
- Diagram of nucleotide
- Compare and contrast dna and rna.
- Rna
- Rna splicing
- Synthesis of rna
- Swf
- Dna and rna
- Replication vs transcription venn diagram
- On and off
- Explain rna
- Rna base pairs vs dna
- Colacca
- Ribosom
- Rna secondary structure prediction
- Structure of chromosome
- Rna transcription
- Dna vs rna diagram
- Rna wheel
- Where are ribosomal rna produced
- Corona virus dna or rna