Identification of oriT and a recombination hot spot in the IncA/C plasmid backbone

Hegyi, Anna; Szabó, Márton; Olasz, Ferenc; Kiss, János

doi:10.1038/s41598-017-11097-0

Cited by 20 publications

(44 citation statements)

References 55 publications

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“…MobI is required for conjugative transfer of IncC plasmids and SXT/R391 integrative and conjugative elements (ICEs) as well as GIs that mimic the oriT locus of the latter but lack a mobI gene (10,40,41). In contrast, deletion of mobI in the helper element does not abolish transfer of pCloDF13 and SGI1, which possess unique oriT loci and cognate mobilization proteins MobBC for pCloDF13 and MpsAB for SGI1 (12,16,40,42). MGIVchHai6 lacks the mobilization genes mpsAB and the oriT locus that are essential for SGI1 mobilization (13,16).…”

Section: Discussionmentioning

confidence: 99%

“…TraI belongs to the MOB H1 family of relaxases, and together with the product of mobI C , is essential for initiation of conjugative transfer at the origin of transfer (oriT) (10,11). MobI C is responsible for recognition of the oriT locus of IncC plasmids that is located immediately upstream of mobI C (12). Unlike other transfer genes, mobI C seems to be expressed in an AcaCD-independent manner (9).…”

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confidence: 99%

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Antibiotic Resistance in Vibrio cholerae: Mechanistic Insights from IncC Plasmid-Mediated Dissemination of a Novel Family of Genomic Islands Inserted at trmE

Rivard

Colwell

Burrus

2020

mSphere

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Cholera remains a formidable disease, and reports of multidrug-resistant strains of the causative agent Vibrio cholerae have become common during the last 3 decades. The pervasiveness of resistance determinants has largely been ascribed to mobile genetic elements, including SXT/R391 integrative conjugative elements, IncC plasmids, and genomic islands (GIs). Conjugative transfer of IncC plasmids is activated by the master activator AcaCD whose regulatory network extends to chromosomally integrated GIs. MGIVchHai6 is a multidrug resistance GI integrated at the 3′ end of trmE (mnmE or thdF) in chromosome 1 of non-O1/non-O139 V. cholerae clinical isolates from the 2010 Haitian cholera outbreak. In the presence of an IncC plasmid expressing AcaCD, MGIVchHai6 excises from the chromosome and transfers at high frequency. Herein, the mechanism of mobilization of MGIVchHai6 GIs by IncC plasmids was dissected. Our results show that AcaCD drives expression of GI-borne genes, including xis and mobIM, involved in excision and mobilization. A 49-bp fragment upstream of mobIM was found to serve as the minimal origin of transfer (oriT) of MGIVchHai6. The direction of transfer initiated at oriT was determined using IncC plasmid-driven mobilization of chromosomal markers via MGIVchHai6. In addition, IncC plasmid-encoded factors, including the relaxase TraI, were found to be required for GI transfer. Finally, in silico exploration of Gammaproteobacteria genomes identified 47 novel related and potentially AcaCD-responsive GIs in 13 different genera. Despite sharing conserved features, these GIs integrate at trmE, yicC, or dusA and carry a diverse cargo of genes involved in phage resistance. IMPORTANCE The increasing association of the etiological agent of cholera, Vibrio cholerae serogroup O1 and O139, with multiple antibiotic resistance threatens to deprive health practitioners of this effective tool. Drug resistance in cholera results mainly from acquisition of mobile genetic elements. Genomic islands conferring multidrug resistance and mobilizable by IncC conjugative plasmids were reported to circulate in non-O1/non-O139 V. cholerae clinical strains isolated from the 2010 Haitian cholera outbreak. As these genomic islands can be transmitted to pandemic V. cholerae serogroups, their mechanism of transmission needed to be investigated. Our research revealed plasmid- and genomic island-encoded factors required for the resistance island excision, mobilization, and integration, as well as regulation of these functions. The discovery of related genomic islands carrying diverse phage resistance genes but lacking antibiotic resistance-conferring genes in a wide range of marine dwelling bacteria suggests that these elements are ancient and recently acquired drug resistance genes.

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

Antibiotic Resistance in Vibrio cholerae: Mechanistic Insights from IncC Plasmid-Mediated Dissemination of a Novel Family of Genomic Islands Inserted at trmE

Rivard

Colwell

Burrus

2020

mSphere

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“…The relaxase-like gene mob I is also required for IncC transfer ( Carraro et al, 2014b ). While the biochemical function of the gene is unknown, it is located immediately downstream of the ori T and essential for plasmid transfer, but unrelated to SGI1 mobilization ( Hegyi et al, 2017 ). In IncC plasmids, the gene eex C facilitates entry exclusion toward IncA plasmids as well as undefined incompatibility groups by recognizing tra G ( Humbert et al, 2019 ).…”

Section: Inccmentioning

confidence: 99%

Transferable Plasmids of Salmonella enterica Associated With Antibiotic Resistance Genes

2020

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Salmonella enterica is a common foodborne illness in the United States and globally. An increasing number of Salmonella infections are resistant to antibiotics, and many of the genes responsible for those resistances are carried by plasmids. Plasmids are important mediators of horizontal gene exchange, which could potentially increase the spread of antibiotic resistance (AR) genes. Twenty-eight different incompatibility groups of plasmids have been described in Enterobacteriaceae. Incompatibility groups differ in their accessory gene content, replication mechanisms, and their associations with Salmonella serotypes and animal sources. Plasmids also differ in their ability to conjugate or be mobilized, essential genes, and conditions required for transfer. It is important to understand the differences in gene content and transfer mechanisms to accurately determine the impact of plasmids on the dissemination and persistence of antibiotic resistance genes. This review will cover the most common plasmid incompatibility groups present in S. enterica with a focus on the transfer mechanisms and associated antibiotic resistance genes.

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“…Figure 4A)(20,57,58). Finally, none of the 8 genes of pVCR94 Sp2 that are absent inpVCR94 Sp were expressed under the control of an AcaCD-activatable promoter (Figures 2 and 4A).…”

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confidence: 96%

Crucial Role ofSalmonellaGenomic Island 1 Master Activator in Parasitism of IncC plasmids

Durand

Huguet

Rivard

et al. 2020

Preprint

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IncC conjugative plasmids and the multiple variants of Salmonella Genomic Island 1 (SGI1) are two functionally interacting families of mobile genetic elements commonly associated with multidrug resistance in Gammaproteobacteria. SGI1 and its siblings are specifically mobilised in trans by IncC conjugative plasmids. Conjugative transfer of IncC plasmids is activated by the plasmid-encoded master activator AcaCD. SGI1 carries five AcaCD-responsive promoters that drive the expression of genes involved in its excision, replication, and mobilisation. SGI1 encodes an AcaCD homologue, the transcriptional activator complex SgaCD (also known as FlhDCSGI1) that seems to recognise and activate the same SGI1 promoters. Here, we investigated the relevance of SgaCD in SGI1’s lifecycle. Mating assays revealed the requirement for SgaCD and its IncC-encoded counterpart AcaCD in the mobilisation of SGI1. An integrative approach combining ChIP-exo, Cappable-seq, and RNA-seq confirmed that SgaCD activates each of the 18 AcaCD-responsive promoters driving the expression of the plasmid transfer functions. A comprehensive analysis of the activity of the complete set of AcaCD-responsive promoters in both SGI1 and IncC plasmid was performed through reporter assays. qPCR and flow cytometry assays revealed that SgaCD is essential for the excision and replication of SGI1, and the destabilisation of the helper IncC plasmid.

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Identification of oriT and a recombination hot spot in the IncA/C plasmid backbone

Cited by 20 publications

References 55 publications

Antibiotic Resistance in Vibrio cholerae: Mechanistic Insights from IncC Plasmid-Mediated Dissemination of a Novel Family of Genomic Islands Inserted at trmE

Antibiotic Resistance in Vibrio cholerae: Mechanistic Insights from IncC Plasmid-Mediated Dissemination of a Novel Family of Genomic Islands Inserted at trmE

Transferable Plasmids of Salmonella enterica Associated With Antibiotic Resistance Genes

Crucial Role ofSalmonellaGenomic Island 1 Master Activator in Parasitism of IncC plasmids

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