Role of reverse transcription in the generation of extrachromosomal copia mobile genetic elements

Nature ◽  
1984 ◽  
Vol 310 (5977) ◽  
pp. 514-516 ◽  
Author(s):  
Andrew J. Flavell
Keyword(s):  
Reverse Transcription ◽  
Mobile Genetic Elements ◽  
Genetic Elements

scholarly journals Type I toxin-antitoxin systems contribute to the maintenance of mobile genetic elements in Clostridioides difficile

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Johann Peltier ◽  
Audrey Hamiot ◽  
Julian R. Garneau ◽  
Pierre Boudry ◽  
Anna Maikova ◽  
...  
Keyword(s):  
Ectopic Expression ◽  
Mobile Genetic Elements ◽  
Toxin Gene ◽  
Type I ◽  
Genetic Elements ◽  
Clostridioides Difficile ◽  
Bacterial Chromosomes ◽  
Toxin Protein

AbstractToxin-antitoxin (TA) systems are widespread on mobile genetic elements and in bacterial chromosomes. In type I TA, synthesis of the toxin protein is prevented by the transcription of an antitoxin RNA. The first type I TA were recently identified in the human enteropathogen Clostridioides difficile. Here we report the characterization of five additional type I TA within phiCD630-1 (CD0977.1-RCd11, CD0904.1-RCd13 and CD0956.3-RCd14) and phiCD630-2 (CD2889-RCd12 and CD2907.2-RCd15) prophages of C. difficile strain 630. Toxin genes encode 34 to 47 amino acid peptides and their ectopic expression in C. difficile induces growth arrest that is neutralized by antitoxin RNA co-expression. We show that type I TA located within the phiCD630-1 prophage contribute to its stability and heritability. We have made use of a type I TA toxin gene to generate an efficient mutagenesis tool for this bacterium that allowed investigation of the role of these widespread TA in prophage maintenance.

scholarly journals Genetic dominance governs the evolution and spread of mobile genetic elements in bacteria

2020 ◽  
Vol 117 (27) ◽  
pp. 15755-15762
Author(s):  
Jerónimo Rodríguez-Beltrán ◽  
Vidar Sørum ◽  
Macarena Toll-Riera ◽  
Carmen de la Vega ◽  
Rafael Peña-Miller ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Mobile Genetic Elements ◽  
Model System ◽  
Host Bacterium ◽  
Wild Type ◽  
Bacterial Evolution ◽  
Human Interest ◽  
Genetic Dominance ◽  
Genetic Elements

Mobile genetic elements (MGEs), such as plasmids, promote bacterial evolution through horizontal gene transfer (HGT). However, the rules governing the repertoire of traits encoded on MGEs remain unclear. In this study, we uncovered the central role of genetic dominance shaping genetic cargo in MGEs, using antibiotic resistance as a model system. MGEs are typically present in more than one copy per host bacterium, and as a consequence, genetic dominance favors the fixation of dominant mutations over recessive ones. In addition, genetic dominance also determines the phenotypic effects of horizontally acquired MGE-encoded genes, silencing recessive alleles if the recipient bacterium already carries a wild-type copy of the gene. The combination of these two effects governs the catalog of genes encoded on MGEs. Our results help to understand how MGEs evolve and spread, uncovering the neglected influence of genetic dominance on bacterial evolution. Moreover, our findings offer a framework to forecast the spread and evolvability of MGE-encoded genes, which encode traits of key human interest, such as virulence or antibiotic resistance.

scholarly journals Genomics of Atlantic Forest Mycobacteriaceae strains unravels a mobilome diversity with a novel integrative conjugative element and plasmids harbouring T7SS

2020 ◽  
Vol 6 (7) ◽  
Author(s):  
Sergio Mascarenhas Morgado ◽  
Ana Carolina Paulo Vicente
Keyword(s):  
Atlantic Forest ◽  
Mobile Genetic Elements ◽  
Content Type ◽  
Genetic Elements ◽  
Link Type ◽  
Type Vii Secretion ◽  
Integrative Conjugative Element ◽  
Type Vii Secretion System ◽  
Integrative Conjugative Elements

Mobile genetic elements (MGEs) are agents of bacterial evolution and adaptation. Genome sequencing provides an unbiased approach that has revealed an abundance of MGEs in prokaryotes, mainly plasmids and integrative conjugative elements. Nevertheless, many mobilomes, particularly those from environmental bacteria, remain underexplored despite their representing a reservoir of genes that can later emerge in the clinic. Here, we explored the mobilome of the Mycobacteriaceae family, focusing on strains from Brazilian Atlantic Forest soil. Novel Mycolicibacterium and Mycobacteroides strains were identified, with the former ones harbouring linear and circular plasmids encoding the specialized type-VII secretion system (T7SS) and mobility-associated genes. In addition, we also identified a T4SS-mediated integrative conjugative element (ICEMyc226) encoding two T7SSs and a number of xenobiotic degrading genes. Our study uncovers the diversity of the Mycobacteriaceae mobilome, providing the evidence of an ICE in this bacterial family. Moreover, the presence of T7SS genes in an ICE, as well as plasmids, highlights the role of these mobile genetic elements in the dispersion of T7SS.

scholarly journals 102 Role of mobile genetic elements in the virulence of Staphylococcus aureus strains from patients with cystic fibrosis

2017 ◽  
Vol 16 ◽  
pp. S91
Author(s):  
K. Guzman ◽  
M. Cervera-Alamar ◽  
A. García-Ortega ◽  
M. Ziemytè ◽  
M. Martí ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Staphylococcus Aureus ◽  
Mobile Genetic Elements ◽  
Genetic Elements

scholarly journals Virulence and resistance properties of E. coli isolated from urine samples of hospitalized patients in Rio de Janeiro, Brazil – The role of mobile genetic elements

2020 ◽  
Vol 310 (8) ◽  
pp. 151453
Author(s):  
Ana Carolina da Cruz Campos ◽  
Natacha Couto ◽  
Nathália Lucas da Silva Andrade ◽  
Alex W. Friedrich ◽  
Ana Cláudia de Paula Rosa ◽  
...  
Keyword(s):  
Rio De Janeiro ◽  
Mobile Genetic Elements ◽  
Hospitalized Patients ◽  
Urine Samples ◽  
E Coli ◽  
Genetic Elements

scholarly journals Expanding the type IIB DNA topoisomerase family: identification of new topoisomerase and topoisomerase-like proteins in mobile genetic elements

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Tomio S Takahashi ◽  
Violette Da Cunha ◽  
Mart Krupovic ◽  
Claudine Mayer ◽  
Patrick Forterre ◽  
...  
Keyword(s):  
Mobile Genetic Elements ◽  
Dna Topology ◽  
Rapid Expansion ◽  
Dna Topoisomerase ◽  
Dna Topoisomerases ◽  
Origin And Evolution ◽  
Bacterial Phyla ◽  
Genetic Elements ◽  
Archaeal Viruses

Abstract The control of DNA topology by DNA topoisomerases is essential for virtually all DNA transactions in the cell. These enzymes, present in every organism, exist as several non-homologous families. We previously identified a small group of atypical type IIB topoisomerases, called Topo VIII, mainly encoded by plasmids. Here, taking advantage of the rapid expansion of sequence databases, we identified new putative Topo VIII homologs. Our analyses confirm the exclusivity of the corresponding genes to mobile genetic elements (MGE) and extend their distribution to nine different bacterial phyla and one archaeal superphylum. Notably, we discovered another subfamily of topoisomerases, dubbed ‘Mini-A’, including distant homologs of type IIB topoisomerases and encoded by extrachromosomal and integrated bacterial and archaeal viruses. Interestingly, a short, functionally uncharacterized motif at the C-terminal extremity of type IIB topoisomerases appears sufficient to discriminate between Mini-A, Topo VI and Topo VIII subfamilies. This motif could be a key element for understanding the differences between the three subfamilies. Collectively, this work leads to an updated model for the origin and evolution of the type IIB topoisomerase family and raises questions regarding the role of topoisomerases during replication of MGE in bacteria and archaea.

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