scholarly journals Engineering multigene expression in vitro and in vivo with small terminators for T7 RNA polymerase

2009 ◽  
Vol 104 (6) ◽  
pp. 1189-1196 ◽  
Author(s):  
Liping Du ◽  
Rong Gao ◽  
Anthony C. Forster
Keyword(s):  
Rna Polymerase ◽  
T7 Rna Polymerase ◽  
Multigene Expression

In vivo and in vitro activities of point mutants of the bacteriophage T7 RNA polymerase promoter

Biochemistry ◽  
1992 ◽  
Vol 31 (37) ◽  
pp. 9073-9080 ◽  
Author(s):  
Richard A. Ikeda ◽  
G. Sakuntala Warshamana ◽  
Lisa L. Chang
Keyword(s):  
Rna Polymerase ◽  
T7 Rna Polymerase ◽  
Bacteriophage T7 ◽  
Rna Polymerase Promoter

scholarly journals Engineering efficient termination of bacteriophage T7 RNA polymerase transcription

2021 ◽  
Author(s):  
Diana Gabriela Calvopina Chavez ◽  
Mikaela Anne Gardner ◽  
Joel S Griffitts
Keyword(s):  
Rna Polymerase ◽  
Molecular Level ◽  
Expression System ◽  
T7 Rna Polymerase ◽  
Bacteriophage T7 ◽  
Lower Efficiency ◽  
Transcriptional Termination ◽  
T7 Polymerase

The bacteriophage T7 expression system is one of the most prominent transcription systems used in biotechnology and molecular-level research. However, T7 RNA polymerase is prone to read-through transcription due to its high processivity. As a consequence, enforcing efficient transcriptional termination is difficult. The termination hairpin found natively in the T7 genome is adapted to be inefficient, exhibiting 62% termination efficiency in vivo and even lower efficiency in vitro. In this study, we engineered a series of sequences that outperform the efficiency of the native terminator hairpin. By embedding a previously discovered 8-nucleotide T7 polymerase pause sequence within a synthetic hairpin sequence, we observed in vivo termination efficiency of 91%; by joining two short sequences into a tandem 2-hairpin structure, termination efficiency was increased to 98% in vivo and 91% in vitro. This study also tests the ability of these engineered sequences to terminate transcription of the Escherichia coli RNA polymerase. Two out of three of the most successful T7 polymerase terminators also facilitated termination of the bacterial polymerase with around 99% efficiency.

scholarly journals Synthetic logic circuits using RNA aptamer against T7 RNA polymerase

2014 ◽  
Author(s):  
Jongmin Kim ◽  
Juan F Quijano ◽  
Enoch Yeung ◽  
Richard M Murray
Keyword(s):  
Rna Polymerase ◽  
Expression System ◽  
Building Blocks ◽  
Logic Circuits ◽  
T7 Rna Polymerase ◽  
Free Expression ◽  
Rna Aptamer ◽  
Cell Free Expression System

Recent advances in nucleic acids engineering introduced several RNA-based regulatory components for synthetic gene circuits, expanding the toolsets to engineer organisms. In this work, we designed genetic circuits implementing an RNA aptamer previously described to have the capability of binding to the T7 RNA polymerase and inhibiting its activity in vitro. Using in vitro transcription assays, we first demonstrated the utility of the RNA aptamer in combination with programmable synthetic transcription networks. As a step to quickly assess the feasibility of aptamer functions in vivo, a cell-free expression system was used as a breadboard to emulate the in vivo conditions of E. coli. We tested the aptamer and its three sequence variants in the cell-free expression system, verifying the aptamer functionality in the cell-free testbed. In vivo expression of aptamer and its variants demonstrated control over GFP expression driven by T7 RNA polymerase with different response curves, indicating its ability to serve as building blocks for both logic circuits and transcriptional cascades. This work elucidates the potential of RNA-based regulators for cell programming with improved controllability leveraging the fast production and degradation time scales of RNA molecules.

Directed Evolution of a Panel of Orthogonal T7 RNA Polymerase Variants for in Vivo or in Vitro Synthetic Circuitry

2014 ◽  
Vol 4 (10) ◽  
pp. 1070-1076 ◽  
Author(s):  
Adam J. Meyer ◽  
Jared W. Ellefson ◽  
Andrew D. Ellington
Keyword(s):  
Rna Polymerase ◽  
Directed Evolution ◽  
T7 Rna Polymerase

scholarly journals In vivo and in vitro transcription of T7 early genes by T7 RNA polymerase

FEBS Letters ◽  
1973 ◽  
Vol 33 (3) ◽  
pp. 335-338 ◽  
Author(s):  
J.R. Lillehaug ◽  
D. Helland ◽  
N.O. Sjöberg
Keyword(s):  
Rna Polymerase ◽  
In Vitro Transcription ◽  
T7 Rna Polymerase ◽  
Early Genes

scholarly journals Multigene expression in vivo: Supremacy of large versus small terminators for T7 RNA polymerase

2011 ◽  
Vol 109 (4) ◽  
pp. 1043-1050 ◽  
Author(s):  
Liping Du ◽  
Seth Villarreal ◽  
Anthony C. Forster
Keyword(s):  
Rna Polymerase ◽  
T7 Rna Polymerase ◽  
Multigene Expression

scholarly journals In vivo diversification of target genomic sites using processive T7 RNA polymerase-base deaminase fusions blocked by RNA-guided dCas9

2019 ◽  
Author(s):  
Beatriz Álvarez ◽  
Mario Mencía ◽  
Víctor de Lorenzo ◽  
Luis Ángel Fernández
Keyword(s):  
Rna Polymerase ◽  
T7 Rna Polymerase ◽  
Target Sequence ◽  
Transcriptional Elongation ◽  
E Coli ◽  
Dna Strands ◽  
In Cells

AbstractDiversification of specific DNA segments typically involve in vitro generation of large sequence libraries and their introduction in cells for selection. Alternative in vivo mutagenesis systems on cells often show deleterious offsite mutations and restricted capabilities. To overcome these limitations, we have developed an in vivo platform to diversify specific DNA segments based on protein fusions between various base deaminases (BD) and the T7 RNA polymerase (T7RNAP) that recognizes a cognate promoter oriented towards the target sequence. The transcriptional elongation of these fusions generates transitions C to T or A to G on both DNA strands and in long DNA segments. To delimit the boundaries of the diversified DNA, the catalytically dead Cas9 (dCas9) is tethered with custom-designed crRNAs as a “roadblock” for BD-T7RNAP elongation. While the efficiency of this platform is demonstrated in E. coli, the system can be adapted to a variety of bacterial and eukaryotic hosts.

scholarly journals Functional dissection of the catalytic mechanism of mammalian RNA polymerase II

2005 ◽  
Vol 83 (4) ◽  
pp. 497-504 ◽  
Author(s):  
Benoit Coulombe ◽  
Marie-France Langelier
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Catalytic Mechanism ◽  
Mutational Analysis ◽  
Structural Elements ◽  
Catalytic Mechanisms ◽  
Rnap Ii ◽  
Affinity Peptide

High resolution X-ray crystal structures of multisubunit RNA polymerases (RNAP) have contributed to our understanding of transcriptional mechanisms. They also provided a powerful guide for the design of experiments aimed at further characterizing the molecular stages of the transcription reaction. Our laboratory used tandem-affinity peptide purification in native conditions to isolate human RNAP II variants that had site-specific mutations in structural elements located strategically within the enzyme's catalytic center. Both in vitro and in vivo analyses of these mutants revealed novel features of the catalytic mechanisms involving this enzyme.Key words: RNA polymerase II, transcriptional mechanisms, mutational analysis, mRNA synthesis.

scholarly journals Direct Interaction between the Subunit RAP30 of Transcription Factor IIF (TFIIF) and RNA Polymerase Subunit 5, Which Contributes to the Association between TFIIF and RNA Polymerase II

2001 ◽  
Vol 276 (15) ◽  
pp. 12266-12273 ◽  
Author(s):  
Wenxiang Wei ◽  
Dorjbal Dorjsuren ◽  
Yong Lin ◽  
Weiping Qin ◽  
Takahiro Nomura ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Middle Part ◽  
Wild Type ◽  
Binding Region ◽  
Pol Ii ◽  
Transcription Factor Iif ◽  
B Virus

The general transcription factor IIF (TFIIF) assembled in the initiation complex, and RAP30 of TFIIF, have been shown to associate with RNA polymerase II (pol II), although it remains unclear which pol II subunit is responsible for the interaction. We examined whether TFIIF interacts with RNA polymerase II subunit 5 (RPB5), the exposed domain of which binds transcriptional regulatory factors such as hepatitis B virus X protein and a novel regulatory protein, RPB5-mediating protein. The results demonstrated that RPB5 directly binds RAP30in vitrousing purified recombinant proteins andin vivoin COS1 cells transiently expressing recombinant RAP30 and RPB5. The RAP30-binding region was mapped to the central region (amino acids (aa) 47–120) of RPB5, which partly overlaps the hepatitis B virus X protein-binding region. Although the middle part (aa 101–170) and the N-terminus (aa 1–100) of RAP30 independently bound RPB5, the latter was not involved in the RPB5 binding when RAP30 was present in TFIIF complex. Scanning of the middle part of RAP30 by clustered alanine substitutions and then point alanine substitutions pinpointed two residues critical for the RPB5 binding inin vitroandin vivoassays. Wild type but not mutants Y124A and Q131A of RAP30 coexpressed with FLAG-RAP74 efficiently recovered endogenous RPB5 to the FLAG-RAP74-bound anti-FLAG M2 resin. The recovered endogenous RPB5 is assembled in pol II as demonstrated immunologically. Interestingly, coexpression of the central region of RPB5 and wild type RAP30 inhibited recovery of endogenous pol II to the FLAG-RAP74-bound M2 resin, strongly suggesting that the RAP30-binding region of RPB5 inhibited the association of TFIIF and pol II. The exposed domain of RPB5 interacts with RAP30 of TFIIF and is important for the association between pol II and TFIIF.

scholarly journals Interactions between RNA polymerase and the core recognition element are a determinant of transcription start site selection

2016 ◽  
Vol 113 (21) ◽  
pp. E2899-E2905 ◽  
Author(s):  
Irina O. Vvedenskaya ◽  
Hanif Vahedian-Movahed ◽  
Yuanchao Zhang ◽  
Deanne M. Taylor ◽  
Richard H. Ebright ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Transcription Start Site ◽  
Transcription Initiation ◽  
Specific Protein ◽  
Start Site ◽  
Transcription Start ◽  
Transcription Bubble ◽  
Recognition Element

During transcription initiation, RNA polymerase (RNAP) holoenzyme unwinds ∼13 bp of promoter DNA, forming an RNAP-promoter open complex (RPo) containing a single-stranded transcription bubble, and selects a template-strand nucleotide to serve as the transcription start site (TSS). In RPo, RNAP core enzyme makes sequence-specific protein–DNA interactions with the downstream part of the nontemplate strand of the transcription bubble (“core recognition element,” CRE). Here, we investigated whether sequence-specific RNAP–CRE interactions affect TSS selection. To do this, we used two next-generation sequencing-based approaches to compare the TSS profile of WT RNAP to that of an RNAP derivative defective in sequence-specific RNAP–CRE interactions. First, using massively systematic transcript end readout, MASTER, we assessed effects of RNAP–CRE interactions on TSS selection in vitro and in vivo for a library of 47 (∼16,000) consensus promoters containing different TSS region sequences, and we observed that the TSS profile of the RNAP derivative defective in RNAP–CRE interactions differed from that of WT RNAP, in a manner that correlated with the presence of consensus CRE sequences in the TSS region. Second, using 5′ merodiploid native-elongating-transcript sequencing, 5′ mNET-seq, we assessed effects of RNAP–CRE interactions at natural promoters in Escherichia coli, and we identified 39 promoters at which RNAP–CRE interactions determine TSS selection. Our findings establish RNAP–CRE interactions are a functional determinant of TSS selection. We propose that RNAP–CRE interactions modulate the position of the downstream end of the transcription bubble in RPo, and thereby modulate TSS selection, which involves transcription bubble expansion or transcription bubble contraction (scrunching or antiscrunching).

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