Figure 6.

AtPolIA and AtPolIB execute MMEJ on mismatched substrates. (A) Oligonucleotide substrates containing mismatches annealed to promote MMEJ. The sequence of the microhomologous sequence of the single-stranded oligonucleotides is indicated. The mismatches are colored in red, whereas Watson-Crick pairs are colored in white. The arrangement includes mismatches located one and two nucleotides after the 3′-OH (I and II), located at the 3′-OH (III and IV), and located three and four nucleotides before the 3′-OH (V and VI). (B and C) MMEJ reactions executed by exonuclease deficient AtPolIA exo- (B) and AtPolIB exo^– (C) on single-stranded substrates. The substrate without added polymerase is indicated by a negative sign (−), whereas reactions including DNA polymerase are indicated by a positive sign (+). The migration for substrates and MMEJ products are indicated. (D) Denaturing acrylamide gel showing the formation of MMEJ products by AtPolIB exo^– on MMEJ with 3′-OH mismatches (substrates III and IV) annealed with the MH-8 oligonucleotide in the presence of individual nucleotides.