scholarly journals Targetron-assisted delivery of exogenous DNA sequences into Pseudomonas putida through CRISPR-aided counterselection

2021 ◽  
Author(s):  
Elena Velazquez ◽  
Yamal Al-ramahi ◽  
Jonathan Tellechea-Luzardo ◽  
Natalio Krasnogor ◽  
Victor de Lorenzo
Keyword(s):  
Pseudomonas Putida ◽  
Genome Editing ◽  
Dna Sequences ◽  
Broad Host Range ◽  
Gram Negative Bacteria ◽  
Exogenous Dna ◽  
Gram Negative ◽  
Conditional Expression ◽  
Assisted Delivery ◽  
Wide Range

Genome editing methods based on Group II introns (known as Targetron technology) have been long used as a gene knock-out strategy in a wide range of organisms in a fashion independent of homologous recombination. Yet, their utility as delivery systems has been typically suboptimal because of their reduced efficiency of insertion when they carry exogenous sequences. We show that this limitation can be tackled and Targetron adapted as a general tool in Gram-negative bacteria. To this end, a set of broad host range standardized vectors were designed for conditional expression of the Ll.LtrB intron. After testing the correct functionality of these plasmids in Escherichia coli and Pseudomonas putida, we created a library of Ll.LtrB variants carrying cargo DNA sequences of different lengths to benchmark the capacity of intron-mediated delivery in these bacteria. Next, we combined CRISPR/Cas9-facilitated counterselection to increase the chances of finding genomic sites inserted with the thereby engineered introns. By following this pipeline, we were able to insert exogenous sequences of up to 600 bp at specific genomic locations in wild-type P. putida KT2440 and its ∆recA derivative. Finally, we were able to apply this technology to successfully tag this strain with an orthogonal short sequence (barcode) that acts as a unique identifier for tracking this microorganism in biotechnological settings. The results with P. putida exemplified the value of the Targetron approach for unrestricted delivery of small DNA fragments to the genomes of Gram-negative bacteria for a suite of genome editing endeavours.

scholarly journals Targetron-Assisted Delivery of Exogenous DNA Sequences into Pseudomonas putida through CRISPR-Aided Counterselection

2021 ◽  
Author(s):  
Elena Velázquez ◽  
Yamal Al-Ramahi ◽  
Jonathan Tellechea-Luzardo ◽  
Natalio Krasnogor ◽  
Víctor de Lorenzo
Keyword(s):  
Pseudomonas Putida ◽  
Dna Sequences ◽  
Exogenous Dna ◽  
Assisted Delivery

scholarly journals Promoters of the broad host range plasmid RK2: analysis of transcription (initiation) in five species of gram-negative bacteria.

Genetics ◽  
1992 ◽  
Vol 130 (1) ◽  
pp. 27-36 ◽  
Author(s):  
A Greener ◽  
S M Lehman ◽  
D R Helinski
Keyword(s):  
Host Range ◽  
Transcription Initiation ◽  
Promoter Activity ◽  
Firefly Luciferase ◽  
Broad Host Range ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Broad Host Range Plasmid ◽  
Transcriptional Start Sites ◽  
Plasmid Rk2

Abstract A broad host range cloning vector was constructed, suitable for monitoring promoter activity in diverse Gram-negative bacteria. This vector, derived from plasmid RSF1010, utilized the firefly luciferase gene as the reporter, since the assay for its bioluminescent product is sensitive, and measurements can be made without background from the host. Twelve DNA fragments with promoter activity were obtained from broad host range plasmid RK2 and inserted into the RSF1010 derived vector. The relative luciferase activities were determined for these fragments in five species of Gram-negative bacteria. In addition, four promoters were analyzed by primer extension to locate transcriptional start sites in each host. The results show that several of the promoters vary substantially in relative strengths or utilize different transcriptional start sites in different bacteria. Other promoters exhibited similar activities and identical start sites in the five hosts examined.

scholarly journals TALEN and CRISPR/Cas Genome Editing Systems: Tools of Discovery

Acta Naturae ◽  
2014 ◽  
Vol 6 (3) ◽  
pp. 19-40 ◽  
Author(s):  
A. A. Nemudryi ◽  
K. R. Valetdinova ◽  
S. P. Medvedev ◽  
S. M. Zakian
Keyword(s):  
Genome Editing ◽  
Dna Sequences ◽  
Genome Engineering ◽  
Disease Modeling ◽  
Regulation Of Gene Expression ◽  
Hereditary Disease ◽  
Transcription Activator ◽  
Wide Range ◽  
High Standards ◽  
Phenotype Formation

Precise studies of plant, animal and human genomes enable remarkable opportunities of obtained data application in biotechnology and medicine. However, knowing nucleotide sequences isnt enough for understanding of particular genomic elements functional relationship and their role in phenotype formation and disease pathogenesis. In post-genomic era methods allowing genomic DNA sequences manipulation, visualization and regulation of gene expression are rapidly evolving. Though, there are few methods, that meet high standards of efficiency, safety and accessibility for a wide range of researchers. In 2011 and 2013 novel methods of genome editing appeared - this are TALEN (Transcription Activator-Like Effector Nucleases) and CRISPR (Clustered Regulatory Interspaced Short Palindromic Repeats)/Cas9 systems. Although TALEN and CRISPR/Cas9 appeared recently, these systems have proved to be effective and reliable tools for genome engineering. Here we generally review application of these systems for genome editing in conventional model objects of current biology, functional genome screening, cell-based human hereditary disease modeling, epigenome studies and visualization of cellular processes. Additionally, we review general strategies for designing TALEN and CRISPR/Cas9 and analyzing their activity. We also discuss some obstacles researcher can face using these genome editing tools.

scholarly journals Construction of a Broad-Host-Range Tn7-Based Vector for Single-Copy PBAD-Controlled Gene Expression in Gram-Negative Bacteria

2012 ◽  
Vol 79 (2) ◽  
pp. 718-721 ◽  
Author(s):  
F. Heath Damron ◽  
Elizabeth S. McKenney ◽  
Herbert P. Schweizer ◽  
Joanna B. Goldberg
Keyword(s):  
Gene Expression ◽  
Pseudomonas Aeruginosa ◽  
Host Range ◽  
Single Copy ◽  
Broad Host Range ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Content Type ◽  
Delivery Vector ◽  
Inducible Gene

ABSTRACTWe describe a mini-Tn7-based broad-host-range expression cassette for arabinose-inducible gene expression from the PBADpromoter. This delivery vector, pTJ1, can integrate a single copy of a gene into the chromosome of Gram-negative bacteria for diverse genetic applications, of which several are discussed, usingPseudomonas aeruginosaas the model host.

scholarly journals Adaptation of the Yeast URA3 Selection System to Gram-Negative Bacteria and Generation of a ΔbetCDE Pseudomonas putida Strain

2005 ◽  
Vol 71 (2) ◽  
pp. 883-892 ◽  
Author(s):  
Teca Calcagno Galvão ◽  
Víctor de Lorenzo
Keyword(s):  
Pseudomonas Putida ◽  
General Procedure ◽  
Gene Replacement ◽  
Selection Marker ◽  
Homologous Gene ◽  
Gram Negative Bacteria ◽  
Selection System ◽  
Gram Negative ◽  
Acid Sensitivity ◽  
Delivery Vector

ABSTRACT A general procedure for efficient generation of gene knockouts in gram-negative bacteria by the adaptation of the Saccharomyces cerevisiae URA3 selection system is described. A Pseudomonas putida strain lacking the URA3 homolog pyrF (encoding orotidine-5′-phosphate decarboxylase) was constructed, allowing the use of a plasmid-borne copy of the gene as the target of selection. The delivery vector pTEC contains the pyrF gene and promoter, a conditional origin of replication (oriR6K), an origin of transfer (mobRK2), and an antibiotic selection marker flanked by multiple sites for cloning appropriate DNA segments. The versatility of pyrF as a selection system, allowing both positive and negative selection of the marker, and the robustness of the selection, where pyrF is associated with uracil prototrophy and fluoroorotic acid sensitivity, make this setup a powerful tool for efficient homologous gene replacement in gram-negative bacteria. The system has been instrumental for complete deletion of the P. putida choline-O-sulfate utilization operon betCDE, a mutant which could not be produced by any of the other genetic strategies available.

scholarly journals New Diarylheptanoid from Garuga pinnata Roxb

2013 ◽  
Vol 61 (2) ◽  
pp. 131-134 ◽  
Author(s):  
Mst Taslima Khatun ◽  
M. Mahboob Ali Siddiqi ◽  
Al-Mansur MA ◽  
MH Sohrab ◽  
AFM Mustafizur Rahman ◽  
...  
Keyword(s):  
Brine Shrimp ◽  
Microbial Growth ◽  
Stem Bark ◽  
Diffusion Method ◽  
Gram Negative Bacteria ◽  
Disc Diffusion ◽  
Disc Diffusion Method ◽  
Gram Negative ◽  
Wide Range ◽  
Bacteria And Fungi

9´-Desmethylgaruganin I has been isolated from the dichloromethane extract of the stem bark of Garuga pinnata Roxb. The crude extract was screened for antimicrobial activity against a wide range of gram-positive and gram-negative bacteria and fungi by disc diffusion method and cytotoxicity by brine shrimp lethality bioassay. The dichloromethane extract showed moderate inhibitory activity to microbial growth and weak cytotoxicity having LC90 25.703?g-mL–1 DOI: http://dx.doi.org/10.3329/dujs.v61i2.17058 Dhaka Univ. J. Sci. 61(2): 131-134, 2013 (July)

scholarly journals Gene Targeting in Gram-Negative Bacteria by Use of a Mobile Group II Intron (“Targetron”) Expressed from a Broad-Host-Range Vector

2007 ◽  
Vol 73 (8) ◽  
pp. 2735-2743 ◽  
Author(s):  
Jun Yao ◽  
Alan M. Lambowitz
Keyword(s):  
Host Range ◽  
Gene Targeting ◽  
Inducible Promoter ◽  
Broad Host Range ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Efficient Gene ◽  
Range Vector ◽  
Group Ii ◽  
Broad Host Range Vector

ABSTRACT Mobile group II introns (“targetrons”) can be programmed for insertion into virtually any desired DNA target with high frequency and specificity. Here, we show that targetrons expressed via an m-toluic acid-inducible promoter from a broad-host-range vector containing an RK2 minireplicon can be used for efficient gene targeting in a variety of gram-negative bacteria, including Escherichia coli, Pseudomonas aeruginosa, and Agrobacterium tumefaciens. Targetrons expressed from donor plasmids introduced by electroporation or conjugation yielded targeted disruptions at frequencies of 1 to 58% of screened colonies in the E. coli lacZ, P. aeruginosa pqsA and pqsH, and A. tumefaciens aopB and chvI genes. The development of this broad-host-range system for targetron expression should facilitate gene targeting in many bacteria.

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