Figure 8.

Functional analysis of Bat1 repeats within the context of a TALE repeat array. Trimers of identical Bat1 repeats or TALE repeats with the same RVDs as the Bat1 repeats were embedded into the repeat domain of the 17-repeat TALE AvrBs3 that targets the pepper Bs3 promoter (Bs3p). Repeats 5–7 (3xRVD NI in AvrBs3) where replaced either by TALE repeat trimers with the RVDs NN or NG or by trimers of Bat1 repeats 2, 6, 8 and 17. This is shown in cartoon form with dTALE regions shown in light grey with the trimer of Bat1 repeats or dTALE repeats shown as white ovals. The grey rectangle and triangle indicate the native N- and C-terminal regions of AvrBs3, respectively. RVDs are given in each case and the matching bases in the target box underneath. The resulting chimeras (striped bars) were tested for their ability to activate a Bs3p derivative bearing the matching binding site upstream of a uidA (GUS) reporter gene and compared to non-chimeric dTALEs (filled bars) with the same RVDs. Dashed lines separate groups of constructs all with the same RVDs and tested against the same reporter. Barred lines indicate standard deviation. Two-tailed t-tests were used to compare chimeric and non-chimeric dTALEs for each reporter. A double asterisk indicates a P-value of below 0.02 and n.s. indicates a P-value of above 0.05.