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. 2011 Apr 29;6(4):e19537. doi: 10.1371/journal.pone.0019537

Figure 4. Recombination of asymmetric Z-sites.

Figure 4

(A) Altered-specificity zinc finger domains target ZFRs to their cognate Z-sites. Substrates containing two identical Z-sites, with either A, B, or Z flanking motifs (Atn3A, Btn3B, Ztn3Z; Figure 2B), were recombined by ZFR300 variants with alternative zinc finger domains as indicated immediately above each lane. (B) Efficient recombination at asymmetric (Atn3B) Z-sites requires two ZFR300 variants, with ZifA and ZifB specificity. The letters above each lane indicate the binding domains borne by the expressed ZFRs, with specificity for either Zif268 (Z), ZifA (A), or ZifB (B) motifs. exp(α), pACYC184-based ZFR expression plasmid (pαZFR); exp(β), pBR322-based ZFR expression plasmid (pβZFR). (C) Efficient recombination of AcasB site substrates requires co-expression of ZFRA320 and ZFRB320.