UV INDUCED (6-4) PHOTOPRODUCTS ARE DISTRIBUTED DIFFERENTLY THAN CYCLOBUTANE DIMERS IN NUCLEOSOMES |
| |
Authors: | James M Gale Michael J Smerdon † |
| |
Institution: | Biochemistry/Biophysics Program, Washington State University, Pullman 99164-4660. |
| |
Abstract: | We have compared the distributions of two stable UV photoproducts in nucleosome core DNA at the single-nucleotide level using a T4 polymerase-exonuclease mapping procedure. The distribution of pyrimidine-pyrimidone (6-4) dimers was uncovered by reversing the major UV photo-product, cis-syn cyclobutane pyrimidine dimer, with E. coli DNA photolyase and photoreactivating light. Whereas the distribution of total UV photoproducts in nucleosome core DNA forms a striking 10.3 base periodic pattern, the distribution of (6-4) dimers is much more random throughout the nucleosome core domain. Therefore, histone-DNA interactions in nucleosomes strongly modulate formation of the major class of UV-induced photoproducts, while having either a constant effect or no effect on (6-4) dimer formation. |
| |
Keywords: | |
|
|