Figure 4

Incorporation of double and single BrdU residues by Bst exo^- DNA Polymerase into the 441 bp hybrid molecule. Incorporation reactions using BrdUTP alone or in combination with dTTP were carried out with Bst exo^- DNA Polymerase. Lanes M, Perfect 100 bp Ladder (selected bands marked); lane 1, 260 bp BsaI-cleaved PCR (restriction fragment I); lane 2, 208 bp BsaI-cleaved PCR (restriction fragment III); lane 3, BrdUTP-filled restriction fragments I and III, T4 DNA ligase; lane 4, BrdUTP-filled restriction fragments I and III; lane 5, dTTP-filled restriction fragment I and BrdUTP-filled restriction fragment III, T4 DNA ligase; lane 6, dTTP-filled restriction fragment I and BrdU-filled restriction fragment III. Lanes 7-9, controls of enzymes functional purity: lane 7, control PCR fragment with internal BsaI site; lane 8, BsaI-cleaved control PCR fragment; lane 9, BsaI-cleaved control PCR fragment after addition of T4 DNA Ligase; lane M, Perfect 100 bp Ladder. ^{I, III} BsaI restriction fragments numbered as in Figure 1.