Send to

Choose Destination
Mol Cell Biol. 1992 Apr;12(4):1798-804.

Binding of transcription factors creates hot spots for UV photoproducts in vivo.

Author information

Department of Biology, Beckman Research Institute of the City of Hope, Duarte, California 91010.


Cyclobutane dipyrimidines and less than mean value of 6-4 dipyrimidines are the two major classes of mutagenic DNA photoproducts produced by UV irradiation of cells. We developed a method to map cyclobutane dipyrimidines at the DNA sequence level in mammalian cells. The frequency of this class of photoproducts was determined at every dipyrimidine along the human phosphoglycerate kinase-1 (PGK1) promoter sequence and was compared to the UV-induced frequency distribution of mean value of 6-4 dipyrimidines. After irradiation of living cells containing active or inactive PGK1 genes, enzymatic or chemical cleavage at UV photoproducts, and amplification by ligation-mediated polymerase chain reaction, photofootprints were seen in all regions which bind transcription factors and appear as DNase I footprints. Photoproduct frequency within transcription factor binding sites was suppressed or enhanced relative to inactive genes or naked DNA with enhancements of up to 30-fold. Since photoproducts are mutagenic, this indicates that photoproduct (mutation?) hot spots may be tissue specific in mammals.

[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center