scholarly journals A Hopeful Sea-Monster: A Very Large Homologous Recombination Event Impacting the Core Genome of the Marine Pathogen Vibrio anguillarum

2020 ◽  
Vol 11 ◽  
Author(s):  
Nicola M. Coyle ◽  
Kerry L. Bartie ◽  
Sion C. Bayliss ◽  
Michaël Bekaert ◽  
Alexandra Adams ◽  
...  
Keyword(s):  
Homologous Recombination ◽  
Recombination Event ◽  
Core Genome ◽  
Vibrio Anguillarum ◽  
The Core ◽  
Homologous Recombination Event ◽  
Sea Monster

scholarly journals The global dissemination of hospital clones of Enterococcus faecium

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Sebastiaan J. van Hal ◽  
◽  
Rob J. L. Willems ◽  
Theodore Gouliouris ◽  
Susan A. Ballard ◽  
...  
Keyword(s):  
Homologous Recombination ◽  
Enterococcus Faecium ◽  
Core Genome ◽  
Local Level ◽  
Drug Resistant ◽  
Genomic Evolution ◽  
The Core ◽  
Antimicrobial Resistance Genes ◽  
Conserved Genes ◽  
Hospital Associated Infections

Abstract Background The hospital-adapted A1 group of Enterococcus faecium remains an organism of significant concern in the context of drug-resistant hospital-associated infections. How this pathogen evolves and disseminates remains poorly understood. Methods A large, globally representative collection of short-read genomic data from the hospital-associated A1 group of Enterococcus faecium was assembled (n = 973). We analysed, using a novel analysis approach, global diversity in terms of both the dynamics of the accessory genome and homologous recombination among conserved genes. Results Two main modes of genomic evolution continue to shape E. faecium: the acquisition and loss of genes, including antimicrobial resistance genes, through mobile genetic elements including plasmids, and homologous recombination of the core genome. These events lead to new clones emerging at the local level, followed by the erosion of signals of clonality through recombination, and in some identifiable cases producing new clonal clusters. These patterns lead to new, emerging lineages which are able to spread globally over relatively short timeframes. Conclusions The ability of A1 E. faecium to continually present new combinations of genes for potential selection suggests that controlling this pathogen will remain challenging but establishing a framework for understanding genomic evolution is likely to aid in tracking the threats posed by newly emerging lineages.

scholarly journals Effects of poly[d(pGpT).d(pApC)] and poly[d(pCpG).d(pCpG)] repeats on homologous recombination in somatic cells.

1986 ◽  
Vol 6 (11) ◽  
pp. 3948-3953 ◽  
Author(s):  
P Bullock ◽  
J Miller ◽  
M Botchan
Keyword(s):  
Homologous Recombination ◽  
Recombination Event ◽  
Somatic Cells ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Wild Type ◽  
Recombination Product ◽  
Homologous Recombination Event ◽  
Sequencing Studies ◽  
Purine Pyrimidine

Sequencing studies have shown that in somatic cells alternating runs of purines and pyrimidines are frequently associated with recombination crossover points. To test whether such sequences actually promote recombination, we have examined the effects of poly[d(pGpT).d(pApC)] and poly[d(pCpG).d(pCpG)] repeats on a homologous recombination event. The parental molecule used in this study, pSVLD, is capable of generating wild-type simian virus 40 DNA via recombination across two 751-base-pair regions of homology and has been described previously (Miller et al., Proc. Natl. Acad. Sci. USA 81:7534-7538, 1984). Single inserts of either a poly[d(pGpT).d(pApC)] repeat or a poly[d(pCpG).d(pCpG)] repeat were positioned adjacent to one region of homology in such a way that the recombination product, wild-type simian virus 40 DNA, could be formed only by recombination within the homologies and not by recombination across the alternating purine-pyrimidine repeats. We have found that upon transfection of test DNAs into simian cells, a poly[d(pCpG).d(pCpG)] repeat enhanced homologous recombination 10- to 15-fold, whereas a poly[d(pGpT).d(pApC)] repeat had less effect. These results are discussed in terms of the features of these repeats that might be responsible for promoting homologous recombination.

scholarly journals Ectopic recombination within homologous immunoglobulin mu gene constant regions in a mouse hybridoma cell line.

1992 ◽  
Vol 12 (10) ◽  
pp. 4422-4432 ◽  
Author(s):  
M D Baker ◽  
L R Read
Keyword(s):  
Homologous Recombination ◽  
Recombination Event ◽  
Mutant Cell ◽  
Immunoglobulin M ◽  
Constant Region ◽  
Wild Type ◽  
Ectopic Recombination ◽  
The Third ◽  
Homologous Recombination Event ◽  
Immunoglobulin Mu

We have transferred a pSV2neo vector containing the wild-type constant region of the immunoglobulin mu gene (C mu) into the mutant hybridoma igm482, which bears a 2-bp deletion in the third constant-region exon of its haploid chromosomal mu gene (C mu 3). Independent igm482 transformants contain the wild-type immunoglobulin C mu region stably integrated in ectopic chromosomal positions. We report here that the wild-type immunoglobulin C mu region can function as the donor sequence in a gene conversion event which corrects the 2-bp deletion in the mutant igm482 chromosomal C mu 3 exon. The homologous recombination event restores normal immunoglobulin M production in the mutant cell.

scholarly journals Evidence of Extensive Homologous Recombination in the Core Genome ofRickettsia

2009 ◽  
Vol 2009 ◽  
pp. 1-5 ◽  
Author(s):  
Jinyu Wu ◽  
Tonghai Yu ◽  
Qiyu Bao ◽  
Fangqing Zhao
Keyword(s):  
Homologous Recombination ◽  
Pathogenic Bacteria ◽  
Core Genome ◽  
Phylogenetic Network ◽  
Genomic Analysis ◽  
Intracellular Bacteria ◽  
The Core ◽  
Evolutionary Genomic ◽  
The Impact

The important role of homologous recombination has been extensively demonstrated to be fundamental for genetic variation in bacterial genomes. In contrast to extracellular or facultative intracellular bacteria, obligate intracellular bacteria are considered to be less prone to recombination, especially for their core genomes. InRickettsia, only antigen-related genes were identified to have experienced homologous recombination. In this study, we employed evolutionary genomic approaches to investigate the impact of recombination on the core genome ofRickettsia. Phylogenetic network and phylogenetic compatibility matrix analyses are clearly consistent with the hypothesis that recombination has occurred frequently duringRickettsiaevolution. 28% ofRickettsiacore genes (194 out of 690) are found to present the evidence of recombination under four independent statistical methods. Further functional classification shows that these recombination events occur across all functional categories, with a significant overrepresentation in the cell wall/membrane/envelope biogenesis, which may provide a molecular basis for the parasite adaptation to host immunity. This evolutionary genomic analysis provides insight into the substantial role of recombination in the evolution of the intracellular pathogenic bacteriaRickettsia.

scholarly journals Correction of a deletion mutant by gene targeting with an adenovirus vector.

1993 ◽  
Vol 13 (2) ◽  
pp. 918-927 ◽  
Author(s):  
Q Wang ◽  
M W Taylor
Keyword(s):  
Homologous Recombination ◽  
Recombination Event ◽  
Recombinant Adenovirus ◽  
Adenovirus Vector ◽  
Adenovirus Type ◽  
Promoter Sequences ◽  
Homologous Recombination Event ◽  
Aprt Gene ◽  
Type Gene ◽  
Adenovirus Type 5

The usefulness of adenovirus type 5 as a vector for homologous recombination was examined in CHO cells by using the adenine phosphoribosyltransferase (aprt) gene. Infection of a hemizygous CHO APRT- cell line containing a 3-bp deletion in exon 5 of the aprt gene with a recombinant adenovirus containing the wild-type gene resulted in restoration of the APRT+ phenotype at a frequency of 10(-5) to 10(-6) per infected cell. A relatively high frequency (approximately 6 to 20%) of the transductants appears to result from a homologous recombination event. The mutation on the chromosomal aprt gene is corrected in the homologous recombinants, and APRT expression is restored to a normal hemizygous level. Neither adenovirus nor exogenous promoter sequences are detected in the homologous recombinants. The remaining transductants result from random integration of the aprt gene with the adenovirus sequence. A number of adenovirus vectors containing different promoter sequences linked to the hamster aprt gene were constructed. A possible role for the promoter region in the homologous recombination event was indicated by the lack of homologous recombination in constructs lacking an active promoter.

First Molecular Characterization of an Unequal Homologous Alu-mediated Recombination Event Responsible for Hemophilia

2002 ◽  
Vol 88 (07) ◽  
pp. 12-16 ◽  
Author(s):  
Francisco Vidal ◽  
Elisenda Farssac ◽  
Joan Tusell ◽  
Lluís Puig ◽  
Dominique Gallardo
Keyword(s):  
Homologous Recombination ◽  
Recombination Event ◽  
Gene Deletion ◽  
Hemophilia A ◽  
Multiple Sequence ◽  
Alu Repeats ◽  
Homologous Recombination Event ◽  
Human Disorders ◽  
Pcr Method

SummaryThe large number of Alu repeats in the human genome provides abundant opportunities for unequal homologous recombination events that are responsible of several human diseases. We here describe a novel large FVIII gene deletion from a severe hemophilia A patient in which Alu-repetitive elements are directly involved in the origin of the mutation. Using a long-fragment PCR method, a ∼23 kb deletion was delimited between introns 24 and 25. The resulting FVIII gene had a hybrid 2317-bp intron and lacked exon 25. Absence of exon 25 was confirmed at the RNA level. Multiple sequence alignment of this hybrid intron and normal introns 24 and 25 provided evidence of an homologous recombination event between two Alu repeats and the exact breakpoints were delimited to a 16 bp region. To our knowledge, this is the first report of hemophilia caused by unequal homologous Alu/Alu recombination. This mechanism, commonly related to genetic human disorders, may be involved in a significant number of hemophilia cases considering that FVIII is coded by an Alu-rich gene.

scholarly journals A Natural Large Chromosomal Inversion inLactococcus lactis Is Mediated by Homologous Recombination between Two Insertion Sequences

1998 ◽  
Vol 180 (18) ◽  
pp. 4834-4842 ◽  
Author(s):  
Marie-Line Daveran-Mingot ◽  
Nathalie Campo ◽  
Paul Ritzenthaler ◽  
Pascal Le Bourgeois
Keyword(s):  
Comparative Analysis ◽  
Homologous Recombination ◽  
Recombination Event ◽  
Insertion Sequence ◽  
Single Step ◽  
Nucleotide Sequence Analysis ◽  
Insertion Sequences ◽  
Genetic Element ◽  
Homologous Recombination Event ◽  
Nucleotide Mutation

ABSTRACT Comparative analysis of chromosomal macrorestriction polymorphism of the two closely related Lactococcus lactis subsp.cremoris strains MG1363 and NCDO763 revealed the presence of a large inversion covering half of the genome. To determine what kind of genetic element could be implicated in this rearrangement, the two inversion junctions of MG1363 and NCDO763 chromosomes were cloned and characterized. Nucleotide sequence analysis showed the presence of one copy of the lactococcal IS905 element in each junction. Each copy of this element contained the same nucleotide mutation that inactivates the putative transposase. Comparison of the sequences surrounding the insertion sequence demonstrated that the large inversion arose from a single-step homologous recombination event between the two defective copies of the IS905 element. The large inversion presumably conferred no selective disadvantage on strain NCDO763 because this rearrangement did not alter theoriC-terC symmetry of the chromosome and the local genetic environment.

A Pandrug-Resistant Providencia Carrying Two blaIMP Carbapenemase-Encoding Genes Including blaIMP-69, a New blaIMP Variant, on a Newly Identified Worldwide-Distributed IncC Plasmid

2020 ◽  
Vol 221 (Supplement_2) ◽  
pp. S253-S256
Author(s):  
Xiaoxia Zhang ◽  
Chengcheng Wang ◽  
Yu Feng ◽  
Haiyan Long ◽  
Zhiyong Zong
Keyword(s):  
Antibiotic Resistance ◽  
Amino Acid ◽  
Antimicrobial Resistance ◽  
Homologous Recombination ◽  
Core Genome ◽  
Rectal Swab ◽  
The Core ◽  
Transmissible Plasmid ◽  
Almost All ◽  
Encoding Genes

Abstract Imipenemase (IMP) is a metallo-β-lactamase that confers resistance to almost all β-lactams. Identification of IMP genes is essential for understanding and combatting antibiotic resistance. In this study, we report a pandrug-resistant Providencia strain from a human rectal swab. This strain carried 2 blaIMP carbapenemase genes, blaIMP-69 and blaIMP-4. IMP-69 is a novel IMP variant with an amino acid substitution at A21T compared with IMP-8. blaIMP-69 was found in a blaIMP-69-aacA4 array of an integron on a 165-kilobase (kb) IncC self-transmissible plasmid, whereas blaIMP-4 was located in a blaIMP-4-qacG-aacA4-catB3 array of an integron on a 19-kb nonself-transmissible plasmid. Such coexistence has the potential to allow the generation of new, hybrid blaIMP variants by homologous recombination. The blaIMP-69-carrying IncC plasmid belonged to the core-genome plasmid multilocus sequence typing (cgPMLST) 3.5 type. We found that cgPMLST 3.5 IncC plasmids have been circulating worldwide for decades and may represent a common vehicle mediating the spread of antimicrobial resistance.

Ectopic recombination within homologous immunoglobulin mu gene constant regions in a mouse hybridoma cell line

1992 ◽  
Vol 12 (10) ◽  
pp. 4422-4432
Author(s):  
M D Baker ◽  
L R Read
Keyword(s):  
Homologous Recombination ◽  
Recombination Event ◽  
Mutant Cell ◽  
Immunoglobulin M ◽  
Constant Region ◽  
Wild Type ◽  
Ectopic Recombination ◽  
The Third ◽  
Homologous Recombination Event ◽  
Immunoglobulin Mu

We have transferred a pSV2neo vector containing the wild-type constant region of the immunoglobulin mu gene (C mu) into the mutant hybridoma igm482, which bears a 2-bp deletion in the third constant-region exon of its haploid chromosomal mu gene (C mu 3). Independent igm482 transformants contain the wild-type immunoglobulin C mu region stably integrated in ectopic chromosomal positions. We report here that the wild-type immunoglobulin C mu region can function as the donor sequence in a gene conversion event which corrects the 2-bp deletion in the mutant igm482 chromosomal C mu 3 exon. The homologous recombination event restores normal immunoglobulin M production in the mutant cell.

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