BER in Polβ mutant
extracts. (A) In vitro BER of
OsO4-damaged DNA was performed in yeast cell-free extracts
of the wild-type (WT) strain TC102 (lane 1) and the Polβ deletion
mutant (pol4) strain SK-2-1β (lane
2). +OsO4, damaged pUC18 DNA; –OsO4,
undamaged pGEM3Zf DNA as the internal control. Top, ethidium bromide-stained
gel; bottom, autoradiograph of the gel. (B) In
vitro BER of the uracil-containing 30mer duplex DNA was performed
in yeast cell-free extracts of the wild-type (WT) strains SX46A
(lane 1) and TC102 (lane 2), or in yeast cell-free extracts of the
Polβ deletion mutant (pol4)
strain SK-2-1β (lane 3). Repair products
were separated by electrophoresis on a 20% denaturing polyacrylamide
gel and visualized by autoradiography. DNA size markers in nucleotides
are indicated on the right.