Structural Basis for the Inverted Repeat Preferences of mariner Transposases.
Bottom Line: The inverted repeat (IR) sequences delimiting the left and right ends of many naturally active mariner DNA transposons are non-identical and have different affinities for their transposase.A 3.1 Å resolution crystal structure of the Mos1 paired-end complex containing the pre-cleaved left IR sequences reveals the molecular basis for the reduced affinity of the Mos1 transposase DNA-binding domain for the left IR as compared with the right IR.We find that this is due to the higher efficiency of cleavage and strand transfer of the preferred transposon end.
Affiliation: From the Institute of Cell Biology and.Show MeSH
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Mentions: To establish whether there is an optimal arrangement of IRs for transposon excision, we performed in vitro cleavage reactions (20) (Fig. 3A). Transposons containing either the natural combination of IRR and IRL or two copies of IRR or IRL were created for both Mos1 and Mboumar-9. For Mos1, we found the highest level of transposon excision (9.1%) from the donor plasmid backbone using a transposon containing two Mos1 IRRs (Fig. 3, B and C). Mboumar-9 also had a preference toward one of the inverted repeats, in this case IRL with 10.7% excision (Fig. 3, B and C). In the most active excision reactions (Mos1 with IRR and Mboumar-9 with IRL), excised transposon bands of 1.3 kb can be observed.