PepA and ArgR do not regulate Cre recombination at the bacteriophage P1 loxP site
Publication date: March 2008 Source:Plasmid, Volume 59, Issue 2 Author(s): Alasdair I. MacDonald , Yangjie Lu , Elizabeth A. Kilbride , Aram Akopian , Sean D. Colloms In the lysogenic state, bacteriophage P1 is maintained as a low copy-number circular plasmid. Site-specific recombination at loxP by the phage-encoded Cre protein keeps P1 monomeric, thus helping to ensure stable plasmid inheritance. Two Escherichia coli DNA-binding proteins, PepA and ArgR, were recently reported to be necessary for maintenance or establishment of P1 lysogeny. PepA and ArgR bind to regulatory DNA sequences upstream of the ColE1 cer r...
Source: Plasmid - November 11, 2014 Category: Biotechnology Source Type: research
In situ monitoring of IncF plasmid transfer on semi-solid agar surfaces reveals a limited invasion of plasmids in recipient colonies
In this study, we aimed to monitor the extent of transitory derepression during agar surface matings in situ by comparing plasmid spread of the IncF plasmid R1 and its derepressed mutant R1drd19 at low initial cell densities. A zygotic induction strategy was used to visualize the spatial distribution of fluorescent transconjugants within the heterogeneous environment. Epifluorescence and confocal microscopy revealed different transfer patterns for both plasmids, however, spread beyond the first five recipient cell layers adjacent to the donor cells was not observed. Similar results were observed for other prototypical conj...
Source: Plasmid - November 11, 2014 Category: Biotechnology Source Type: research
General requirements for protein secretion by the F-like conjugation system R1
This study aims to understand mechanisms leading to the initiation of type IV secretion using conjugative plasmid paradigm R1. We analyze the general requirements for plasmid encoded conjugation proteins and DNA sequence within the origin of transfer (oriT) for protein secretion activity using a Cre recombinase reporter system. We find that similar to conjugative plasmid DNA strand transfer, activation of the R1 system for protein secretion depends on binding interactions between the multimeric, ATP-binding coupling protein and the R1 relaxosome including an intact oriT. Evidence for DNA independent protein secretion was n...
Source: Plasmid - November 11, 2014 Category: Biotechnology Source Type: research
Rhizobial extrachromosomal replicon variability, stability and expression in natural niches
Publication date: November 2012 Source:Plasmid, Volume 68, Issue 3 Author(s): Martha G. López-Guerrero , Ernesto Ormeño-Orrillo , José Luis Acosta , Alfredo Mendoza-Vargas , Marco A. Rogel , Miguel Angel Ramírez , Mónica Rosenblueth , Julio Martínez-Romero , Esperanza Martínez-Romero In bacteria, niche adaptation may be determined by mobile extrachromosomal elements. A remarkable characteristic of Rhizobium and Ensifer (Sinorhizobium) but also of Agrobacterium species is that almost half of the genome is contained in several large extrachromosomal replicons (ERs). They encode a plethora of functions, so...
Source: Plasmid - November 11, 2014 Category: Biotechnology Source Type: research
Construction of a doxycycline inducible adipogenic lentiviral expression system
Publication date: January 2013 Source:Plasmid, Volume 69, Issue 1 Author(s): Q. Liu , P.J. Hill , A. Karamitri , K.J.P. Ryan , H.Y. Chen , M.A. Lomax To provide a tool for research on regulating adipocyte differentiation, tetracycline inducible (Tet on) lentiviral expression vectors under the control of an adipose-specific promoter were constructed. The lowest basal expression in the absence of doxycycline and most efficient dose-dependent, doxycycline-induced transient overexpression was observed using vectors constructed with a combination of Tetracycline Responsive Element (TRE) and reverse tetracycline-contro...
Source: Plasmid - November 11, 2014 Category: Biotechnology Source Type: research
