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Preferential formation and repair of chromium-induced DNA adducts and DNA--protein crosslinks in nuclear matrix DNA.

Publication ,  Journal Article
Xu, J; Manning, FC; Patierno, SR
Published in: Carcinogenesis
July 1994

The distributions of chromium-DNA adducts and DNA-protein crosslinks induced by treatment of intact CHO cells with carcinogenic chromium were examined in distinct chromatin subfractions: a chromatin subfraction released by digestion of isolated nuclei with micrococcal nuclease (1SF, 14% of total nuclear DNA), bulk chromatin (74% of total DNA) and a nuclear matrix fraction (12% of total DNA). The identity of the matrix fraction was confirmed by hybridization of DNA from each subfraction with a cDNA probe prepared from total mRNA isolated from CHO cells, which showed that the 1SF and nuclear matrix fractions were 2.3- and 3.8-fold enriched in actively transcribed genes respectively, compared to total unfractionated DNA. Immediately following treatment of cells with 150 microM sodium chromate for 2 h the binding of chromium to each chromatin fraction was found to be non-uniform. Compared with total unfractionated nuclei, the nuclear matrix fractions were enriched in chromatin-bound chromium (3.4-fold), whereas the bulk chromatin fraction was relatively depleted (0.5-fold). Approximately 13% of nuclear chromium was associated with the detergent-soluble lipid component of nuclei. A similar distribution of chromatin-bound chromium was also apparent 24 h after the chromate treatment. Immediately after the 2 h chromate treatment, chromium-DNA adducts were detected in all the chromatin subfractions. Total nuclear and bulk chromatin DNA contained similar levels of this type of damage. The 1SF fraction was depleted approximately 3-fold in this type of damage compared with total nuclear DNA. In contrast, the nuclear matrix was markedly enriched in chromium-DNA adducts (approximately 4-fold compared with total nuclear DNA) at this time. As previously demonstrated, chromium-DNA adducts in total nuclear DNA decreased within the first 24 h, but thereafter persisted at a similar level. Chromium-DNA adducts in nuclear matrix DNA also reached maximum levels at the end of the 2 h treatment and decreased to 68% and 39% of this level by 24 and 48 h after treatment respectively. In contrast, the adduct levels in the 1SF and bulk chromatin fractions did not change up to 48 h after treatment. Chromium-induced DNA-protein crosslinks, which were stable to 8 M urea and 2% SDS, occurred almost exclusively in the nuclear matrix fraction. The crosslinks in this fraction reached a maximum level at the end of the 2 h treatment, but returned to control levels 24 h later.(ABSTRACT TRUNCATED AT 400 WORDS)

Duke Scholars

Published In

Carcinogenesis

DOI

ISSN

0143-3334

Publication Date

July 1994

Volume

15

Issue

7

Start / End Page

1443 / 1450

Location

England

Related Subject Headings

  • Proteins
  • Oncology & Carcinogenesis
  • Nuclear Matrix
  • G1 Phase
  • DNA Repair
  • DNA
  • Cricetinae
  • Chromium
  • Chromatin
  • CHO Cells
 

Citation

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ICMJE
MLA
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Xu, J., Manning, F. C., & Patierno, S. R. (1994). Preferential formation and repair of chromium-induced DNA adducts and DNA--protein crosslinks in nuclear matrix DNA. Carcinogenesis, 15(7), 1443–1450. https://doi.org/10.1093/carcin/15.7.1443
Xu, J., F. C. Manning, and S. R. Patierno. “Preferential formation and repair of chromium-induced DNA adducts and DNA--protein crosslinks in nuclear matrix DNA.Carcinogenesis 15, no. 7 (July 1994): 1443–50. https://doi.org/10.1093/carcin/15.7.1443.
Xu, J., et al. “Preferential formation and repair of chromium-induced DNA adducts and DNA--protein crosslinks in nuclear matrix DNA.Carcinogenesis, vol. 15, no. 7, July 1994, pp. 1443–50. Pubmed, doi:10.1093/carcin/15.7.1443.
Journal cover image

Published In

Carcinogenesis

DOI

ISSN

0143-3334

Publication Date

July 1994

Volume

15

Issue

7

Start / End Page

1443 / 1450

Location

England

Related Subject Headings

  • Proteins
  • Oncology & Carcinogenesis
  • Nuclear Matrix
  • G1 Phase
  • DNA Repair
  • DNA
  • Cricetinae
  • Chromium
  • Chromatin
  • CHO Cells