A TIR IS element carries a pair of (partially conserved) inverted repeats at the two termini of an IS for cleavage and binding of the transposase, as shown in Figure 1 (a), while a non-TIR IS element) does not harbor significant signals around its termini.
When high-affinity transposase binds to the Ds TIRs, binding of further transposase molecules to nearby cryptic sites may be facilitated.
While we did not attempt to detect the binding of the transposase to DNA by an electrophoretic mobility shift assay, we analyzed complex formation by analytical size-exclusion chromatography.
In this idealized situation, synapsis of the transposon ends is simply a product of the sequential binding of the transposase dimer to sites at opposite ends of the element.
P-element transpose by a cut-and-paste mechanism that involves the binding of the transposase to the element TIRs and the excision of the element generating a DSB at the donor site followed by the integration of the element into a different chromosomal site (Beall and Rio 1997; Tang et al. 2007).
This transposition mechanism involves the binding of the transposase to the element TIRs and the excision of the element generating a DSB at the donor site followed by the integration of the element into a different chromosomal site.
A consideration of the conserved and unique aspects of Ds footprints in maize [27], [31], [32], Arabidopsis [23; this work] and yeast [4], [21] suggest that binding of the transposase molecules at Ds TIRs may be sufficient for accurate excision of Ds but that the mechanism of repair of broken ends at the donor site is dependent on host factors.
Both reactions involve the binding of transposase to DNA site B, so they are chemically identical.
Two transposase genes located immediately upstream of novR were found to code for different fragment of a transposase, suggesting that the genomic region encompassing both partial transposase genes may code for a functional transposase at one time.
