CPD Damage Recognition by Transcribing RNA Polymerase II

Abstract

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Mechanism of transcriptional stalling at cisplatin-damaged DNA

“…The DNA-RNA hybrid occupies the upstream positions -1 to -8. The hybrid structure is essentially identical to our previous structures of the complete Pol II elongation complex 9 and the elongation complex containing a CPD lesion at the polymerase active site 8 . However, the downstream DNA duplex adopts a slightly altered position (Fig.…”

“…1e). The change in the downstream DNA position results from the presence of the cisplatin lesion rather than from the scaffold design or the nucleic acid sequences, which were highly similar to those used previously 8 . Structures of free DNA containing a cisplatin lesion 10,11 reveal that the lesion at the center of the duplex leads to DNA bending.…”

“…Here we have used a combination of X-ray crystallography and RNA-extension assays to derive the molecular mechanism of Saccharomyces cerevisiae Pol II stalling at a cisplatin lesion. Comparison of the results with our previous analysis of Pol II stalling at a DNA photolesion, a TT cyclobutane pyrimidine dimer 8 (CPD, Fig. 1a), reveals that the two types of dinucleotide lesions trigger transcriptional stalling by different mechanisms.…”

“…Elongation complexes were reconstituted from the 12-subunit S. cerevisiae Pol II and nucleic acid scaffolds as described 8,9 .…”

“…structural considerations suggest that lesion entry into the active site would be impaired, because translocation of the cisplatin dinucleotide lesion from positions +2/+3 to positions +1/+2 is expected to be disfavored, as is the case for a dinucleotide photolesion 8 .…”