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Title: Ultraviolet damage and nucleosome folding of the 5S ribosomal RNA gene.

The Xenopus borealis somatic 5S ribosomal RNA gene was used as a model system to determine the mutual effects of nucleosome folding and formation of ultraviolet (UV) photoproducts (primarily cis-syn cyclobutane pyrimidine dimers, or CPDs) in chromatin. We analyzed the preferred rotational and translational settings of 5S rDNA on the histone octamer surface after induction of up to 0.8 CPD/nucleosome core (2.5 kJ/m(2) UV dose). DNase I and hydroxyl radical footprints indicate that UV damage at these levels does not affect the average rotational setting of the 5S rDNA molecules. Moreover, a combination of nuclease trimming and restriction enzyme digestion indicates the preferred translational positions of the histone octamer are not affected by this level of UV damage. We also did not observe differences in the UV damage patterns of irradiated 5S rDNA before or after nucleosome formation, indicating there is little difference in the inhibition of nucleosome folding by specific CPD sites in the 5S rRNA gene. Conversely, nucleosome folding significantly restricts CPD formation at all sites in the three helical turns of the nontranscribed strand located in the dyad axis region of the nucleosome, where DNA is bound exclusively by the histone H3-H4 tetramer. Finally, modulation of themore » CPD distribution in a 14 nt long pyrimidine tract correlates with its rotational setting on the histone surface, when the strong sequence bias for CPD formation in this tract is minimized by normalization. These results help establish the mutual roles of histone binding and UV photoproducts on their formation in chromatin.« less
Authors:
 [1] ;  [2] ;  [1] ;  [3] ;  [4]
  1. (Washington State University)
  2. (ASSOC WESTERN UNIVERSITY)
  3. (BATTELLE (PACIFIC NW LAB))
  4. (VISITORS)
Publication Date:
OSTI Identifier:
15003117
Report Number(s):
PNWD-SA-5349
TRN: US200420%%356
DOE Contract Number:
AC06-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Biochemistry; Journal Volume: 39; Journal Issue: 3; Other Information: PBD: 25 Jan 2000
Research Org:
Pacific Northwest National Lab., Richland, WA (US)
Sponsoring Org:
US Department of Energy (US)
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; CHROMATIN; DIGESTION; DISTRIBUTION; DNA; ENZYMES; GENES; HISTONES; HYDROXYL RADICALS; INDUCTION; MODULATION; NUCLEASES; NUCLEOSOMES; PYRIMIDINE DIMERS; PYRIMIDINES; RIBOSOMAL RNA