Target DNA structure plays a critical role in Tn7 transposition

Kuduvalli, Prasad N.; Rao, Jason E.; Craig, Nancy L.

doi:10.1093/emboj/20.4.924

Cited by 77 publications

(112 citation statements)

References 35 publications

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“…TnsD binding induces an asymmetric distortion in the attTn7 target DNA that is essentially responsible for attracting TnsC for target site selection during transposition (Fig. 6A) (56,63). The TnsABC proteins are normally insufficient for Tn7 transposition in vivo or in vitro (64); however, certain gainof-function mutations in the regulator protein TnsC (TnsC*) allow untargeted transposition in the absence of TnsD or TnsE (47,65,66).…”

Section: Chromosomal Insertions Of the I-f Crispr-cas-associated Elemmentioning

confidence: 99%

Recruitment of CRISPR-Cas systems by Tn7-like transposons

Peters

Makarova

Shmakov

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

245

267

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A survey of bacterial and archaeal genomes shows that many Tn7-like transposons contain minimal type I-F CRISPR-Cas systems that consist of fused cas8f and cas5f, cas7f, and cas6f genes and a short CRISPR array. Several small groups of Tn7-like transposons encompass similarly truncated type I-B CRISPR-Cas. This minimal gene complement of the transposon-associated CRISPR-Cas systems implies that they are competent for pre-CRISPR RNA (precrRNA) processing yielding mature crRNAs and target binding but not target cleavage that is required for interference. Phylogenetic analysis demonstrates that evolution of the CRISPR-Cas-containing transposons included a single, ancestral capture of a type I-F locus and two independent instances of type I-B loci capture. We show that the transposon-associated CRISPR arrays contain spacers homologous to plasmid and temperate phage sequences and, in some cases, chromosomal sequences adjacent to the transposon. We hypothesize that the transposon-encoded CRISPR-Cas systems generate displacement (R-loops) in the cognate DNA sites, targeting the transposon to these sites and thus facilitating their spread via plasmids and phages. These findings suggest the existence of RNAguided transposition and fit the guns-for-hire concept whereby mobile genetic elements capture host defense systems and repurpose them for different stages in the life cycle of the element.CRISPR-Cas systems | Tn7 transposon | transposition strategy | crRNA guide | target-site selection

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Section: Chromosomal Insertions Of the I-f Crispr-cas-associated Elemmentioning

confidence: 99%

Recruitment of CRISPR-Cas systems by Tn7-like transposons

Peters

Makarova

Shmakov

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

245

267

View full text Add to dashboard Cite

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“…One of the best-studied examples is the bacterial transposon Tn7, which employs two transposition pathways. In the first, the TnsD protein binds a specific DNA sequence, attTn7, and stimulates transposition by distorting the target DNA (15). In the absence of TnsD, Tn7 prefers to integrate near regions of triplex DNA, which are thought to mimic the distortion induced by TnsD binding (32,33).…”

mentioning

confidence: 99%

Targeted Transposition by the V(D)J Recombinase

Lee¹,

Neiditch²,

Sinden

et al. 2002

Molecular and Cellular Biology

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Cleavage by the V(D)J recombinase at a pair of recombination signal sequences creates two coding ends and two signal ends. The RAG proteins can integrate these signal ends, without sequence specificity, into an unrelated target DNA molecule. Here we demonstrate that such transposition events are greatly stimulated by-and specifically targeted to-hairpins and other distorted DNA structures. The mechanism of target selection by the RAG proteins thus appears to involve recognition of distorted DNA. These data also suggest a novel mechanism for the formation of alternative recombination products termed hybrid joints, in which a signal end is joined to a hairpin coding end. We suggest that hybrid joints may arise by transposition in vivo and propose a new model to account for some recurrent chromosome translocations found in human lymphomas. According to this model, transposition can join antigen receptor loci to partner sites that lack recombination signal sequence elements but bear particular structural features. The RAG proteins are capable of mediating all necessary breakage and joining events on both partner chromosomes; thus, the V(D)J recombinase may be far more culpable for oncogenic translocations than has been suspected.The immune system's vast repertoire of B-and T-cell receptors results from a site-specific gene rearrangement process known as V(D)J recombination. Assorted variable (V), diversity (D), and joining (J) coding gene segments are recombined in developing lymphocyte precursors to form the variable region genes that encode antigen-binding sites of immunoglobulin and T-cell receptor molecules (40). The DNA is first cleaved at specific recombination signal sequences (RSS) located adjacent to the coding segments. RSS consist of conserved heptamer and nonamer sequences, separated by either 12 or 23 nucleotides of spacer DNA (referred to as 12 RSS and 23 RSS). The RAG1 and RAG2 recombinase proteins, assisted by either of the nonspecific DNA-bending proteins HMG1 and HMG2 (41), generate a nick between the RSS and the adjacent coding segment by hydrolysis. The newly formed 3Ј OH group then attacks the phosphodiester bond connecting the coding segment to the RSS on the opposite strand.

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“…TnsABCϩ TnsD proteins promote high frequency insertion into a specific attTn7 site in the Escherichia coli genome (13,14). TnsD binds to the attTn7 site sequence-specifically, and induces DNA distortion that can be recognized by TnsC, which in turn activates the TnsAB machinery (15,16). If the attTn7 site is not available, TnsABC ϩTnsE proteins mediate low frequency insertion into unrelated sites (17,18).…”

mentioning

confidence: 99%

DNA Transposition of Bacteriophage Mu

Haapa-Paananen¹,

Rita²,

Savilahti³

2002

Journal of Biological Chemistry

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The Mu transpositional DNA recombination machinery selects target sites by assembling a protein-DNA complex that interacts with the target DNA and reacts whenever it locates a favorable sequence composition. Splicing of a transposon into the target generates a 5-bp duplication that reflects the original target site. Preferential usage of different target pentamers was examined with a minimal Mu in vitro system and quantitatively compiled consensus sequences for the most preferred and the least preferred sites were generated. When analyzed as base steps, preferences toward certain steps along the 5-bp target site were detected. We further show that insertion sites can be predicted on the basis of additively calculated base step values. Also surrounding sequences influence the preference of a given pentamer; a symmetrical structural component was revealed, suggesting potential hinges at and around the target site.

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Target DNA structure plays a critical role in Tn7 transposition

Cited by 77 publications

References 35 publications

Recruitment of CRISPR-Cas systems by Tn7-like transposons

Recruitment of CRISPR-Cas systems by Tn7-like transposons

Targeted Transposition by the V(D)J Recombinase

DNA Transposition of Bacteriophage Mu

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