Figure 4.

Lack of hpol η leads to loss of reverse transcription activity in human cell extracts. A–F, extracts (0.48 mg protein/ml) of hpol η–deficient (XP-V) and corrected cells were tested with DNA/DNA (A and B), RNA/DNA (C and D), and DNA/RNA (E and F), respectively (1 μm each substrate), in the presence of H₂O (negative control) and dNTPs (1 mm each nucleotide). An unrelated annealed dsDNA/RNA hybrid (poly dA/poly rU) and ssDNA (poly dA) (100 μm) were added to prevent degradation. The reactions were conducted for 10, 30, and 60 min. See “Oligonucleotide substrates” under “Experimental procedures” for the oligonucleotide sequences used.