Specific DNA cleavage mediated by the integrase of conjugative transposon Tn916

Taylor, K L; Churchward, Gordon

doi:10.1128/jb.179.4.1117-1125.1997

Cited by 40 publications

(35 citation statements)

References 53 publications

(88 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Since the two ends are not complementary, the 6-bp "coupling sequences" form a heteroduplex joint in the circular intermediate. During integration, the integrase makes 6-bp staggered cuts on the transposon and at the target site, and integration produces heteroduplexes at the left and right junctions that are resolved by chromosome replication or mismatch repair (15,74,80). Since recombination always occurs between 6 bp of heterologous sequences, it is clear that recombination cannot involve branch migration or strand swapping of homologous sequences through the entire coupling sequence.…”

Section: Tyrosine Recombinases That Violate the Homology Rulementioning

confidence: 99%

Challenging a Paradigm: the Role of DNA Homology in Tyrosine Recombinase Reactions

Rajeev

Malanowska

Gardner

2009

Microbiol Mol Biol Rev

View full text Add to dashboard Cite

SUMMARY A classical feature of the tyrosine recombinase family of proteins catalyzing site-specific recombination, as exemplified by the phage lambda integrase and the Cre and Flp recombinases, is the ability to recombine substrates sharing very limited DNA sequence identity. Decades of research have established the importance of this short stretch of identity within the core regions of the substrates. Since then, several new enzymes that challenge this paradigm have been discovered and require the role of sequence identity in site-specific recombination to be reconsidered. The integrases of the conjugative transposons such as Tn916, Tn1545, and CTnDOT recombine substrates with heterologous core sequences. The integrase of the mobilizable transposon NBU1 performs recombination more efficiently with certain core mismatches. The integration of CTX phage and capture of gene cassettes by integrons also occur by altered mechanisms. In these systems, recombination occurs between mismatched sequences by a single strand exchange. In this review, we discuss literature that led to the formulation of the current strand-swapping isomerization model for tyrosine recombinases. The review then focuses on recent developments on the recombinases that challenged the paradigm that was derived from the studies of early systems.

show abstract

Section: Tyrosine Recombinases That Violate the Homology Rulementioning

confidence: 99%

Challenging a Paradigm: the Role of DNA Homology in Tyrosine Recombinase Reactions

Rajeev

Malanowska

Gardner

2009

Microbiol Mol Biol Rev

View full text Add to dashboard Cite

show abstract

“…The site-specific recombination system of Tn4651 could therefore be considered to be apparently analogous to those encoded by integrons in which the integrases are able to catalyze both the excision and the integration reactions and, to a lesser extent, analogous to those encoded by lysogenic phages and some conjugative transposons (e.g., Tn916 and Tn5276) (18,25,30). With respect to the latter group of mobile elements, the small (Ͻ100 amino acid residues) accessory proteins collectively designated recombination direction factors (RDFs) (e.g., lambda Xis protein) (19) are, in addition to the integrases, required absolutely for site-specific excision, and some RDFs have been shown to bind to specific recognition sequences at the att sites so as to introduce sharp DNA bends (8).…”

Section: Discussionmentioning

confidence: 99%

“…Most members of the resolvase family represented by the TnpR proteins of the class II transposons catalyze only the intramolecular recombination between the two copies of the recombination site (12). In contrast, almost all of the members of the integrase family represented by the phage-encoded integrases catalyze both the intramolecular and intermolecular recombinations, and this family also includes the recombinases that take part in integration of the gene cassettes into the integrons and their excision (11) and the transposition of conjugative transposons (27,30). The TnpI proteins encoded by the two unusual class II transposons, Tn4430 and Tn5401, also belong to the integrase family, and they catalyze the site-specific resolution of their respective cointegrates (5,21).…”

mentioning

confidence: 99%

Site-Specific Recombination System Encoded by Toluene Catabolic Transposon Tn4651

2002

View full text Add to dashboard Cite

The 56-kb class II toluene catabolic transposon Tn4651 from Pseudomonas putida plasmid pWW0 is unique in that (i) its efficient resolution requires, in addition to the 0.2-kb resolution (res) site, the two gene products TnpS and TnpT and (ii) the 2.4-kb tnpT-res-tnpS region is 48 kb apart from the tnpA gene (M. Tsuda, K.-I. Minegishi, and T. Iino, J. Bacteriol. 171:1386-1393, 1989). Detailed analysis of the 2.4-kb region revealed that the tnpS and tnpT genes encoding the putative 323-and 332-amino-acid proteins, respectively, were transcribed divergently with an overlapping 59-bp sequence in the 203-bp res site. The motifs (the R-H-R-Y tetrad in domains I and II with proper spacing) commonly conserved in the integrase family of site-specific recombinases were found in TnpS. In contrast, TnpT did not show any significant amino acid sequence homology to the other proteins that are directly or indirectly involved in recombination. Analysis of site-specific recombination under the Escherichia coli recA cells indicated that (i) the site-specific resolution between the two copies of the res site on a single molecule was catalyzed by TnpS, (ii) the functional res site was located within a 95-bp segment, and (iii) TnpT appeared to have the role of enhancing the site-specific resolution. It was also found that TnpS catalyzed the site-specific recombination between the res sites located at two different molecules to form a cointegrate molecule. Site-specific mutagenesis of the conserved tyrosine residue in TnpS led to the loss of both the resolution and the integration activities, indicating that such a residue took part in both types of recombination.

show abstract

“…Integration in vitro by Tn916 Int cleavage has shown that Int resembles other integrases, in particular those integrases which form transient covalent linkage between the protein C-terminus and 3'-phosphate of the cleaved DNA (98). The N-terminal region of Int binds to directly repeated sequences at the conjugative transposon's termini, while the Cterminal region binds to the regions containing inverted repeats further out on the termini, and is thought to interact with the targeted host sequences (96).…”

Section: The Mechanism Of Conjugative Transpositionmentioning

confidence: 99%

“…Such looping would allow both ends to be bound in close proximity, for concomitant double cleavage and circularization. Int is thought to recognize perfect direct repeats within each of the termini of the conjuagtive transposon, employing DNA binding domains that cleave within the flanking host coupling sequences as it catalyzes cleavage and joining (98).…”

Section: The Mechanism Of Conjugative Transpositionmentioning

confidence: 99%

Conjugative transfer in the dissemination of beta-lactam and aminoglycoside resistance

Waters¹

1999

Front Biosci

View full text Add to dashboard Cite

The dissemination of antibiotic resistance among pathogenic bacteria can be attributed largely to conjugative DNA transfer. The general category of conjugative transfer includes both bacterial plasmid conjugation and the transfer of nonreplicative conjugative transposons. Prototypes for these two systems are the plasmid RK2 and the conjugative transposon Tn916. To address the long-term problem of the increasing prevalence and severity of antibiotic resistance, strategies aimed against conjugative transfer are needed, but their development will require a greater understanding of conjugative resistance gene acquisition. Overviews of the two conjugative transfer systems are presented, to summarize and compare current concepts. Observations regarding transfer of conjugative transposons is consistent with the prevailing model for plasmid conjugation, that is, by the transfer of a single-stranded DNA molecule from the donor to the recipient bacterium, and the generation of the single strand by rolling circle DNA replication. The relevance of vegetative plasmid replication and host range to the spread of multiple drug resistance is discussed, and clinical examples of conjugative transfer of multiple antibiotic resistance illustrate the severity of the current situation. Possible directions, traditional and innovative, are offered to address the conjugative transfer problem in drug resistance, and potentially to break the cycle of antibiotic development followed by the bacterial resistance gene acquisition.

show abstract

Specific DNA cleavage mediated by the integrase of conjugative transposon Tn916

Cited by 40 publications

References 53 publications

Challenging a Paradigm: the Role of DNA Homology in Tyrosine Recombinase Reactions

Challenging a Paradigm: the Role of DNA Homology in Tyrosine Recombinase Reactions

Site-Specific Recombination System Encoded by Toluene Catabolic Transposon Tn4651

Conjugative transfer in the dissemination of beta-lactam and aminoglycoside resistance

Contact Info

Product

Resources

About