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The origin of O6-methylguanine-DNA methyltransferase in Chinese hamster ovary cells transfected with human DNA.

Publication ,  Journal Article
Tano, K; Shiota, S; Remack, JS; Brent, TP; Bigner, DD; Mitra, S
Published in: Mutat Res
September 1991

Transfection of Chinese hamster ovary (CHO) cells with human DNA has been shown in several laboratories to produce clones which stably express the DNA-repair protein, O6-methylguanine-DNA methyltransferase (MGMT), that is lacking in the parent cell lines (Mex- phenotype). We have investigated the genetic origin of the MGMT in a number of such MGMT-positive (Mex+) clones by using human MGMT cDNA and anti-human MGMT antibodies as probes. None of the five independently isolated Mex+ lines has human MGMT gene sequences. Immunoblot analysis confirmed the absence of the human protein in the extracts of these cells. The MGMT mRNA in the lines that express low levels of MGMT (0.6-1.4 x 10(4) molecules/cell) is of the same size (1.1 kb) as that present in hamster liver. One cell line, GC-1, with a much higher level of MGMT (4 x 10(4) molecules/cell) has two MGMT mRNAs, a major species of 1.3 kb and a minor species of 1.8 kb. It has also two MGMT polypeptides (32 and 28 kDa), both of which are larger than the 25 kDa MGMT present in hamster liver and other Mex+ transfectants. These results indicate that the MGMT in all Mex+ CHO cell clones is encoded by the endogenous gene. While spontaneous activation of the MGMT gene cannot be ruled out in the Mex+ cell clones, the intervention of human DNA sequences may be responsible for activation of the endogenous gene in the GC-1 line.

Duke Scholars

Published In

Mutat Res

DOI

ISSN

0027-5107

Publication Date

September 1991

Volume

255

Issue

2

Start / End Page

175 / 182

Location

Netherlands

Related Subject Headings

  • Transfection
  • Transcription, Genetic
  • Oncology & Carcinogenesis
  • O(6)-Methylguanine-DNA Methyltransferase
  • Nucleic Acid Hybridization
  • Methyltransferases
  • Humans
  • Electrophoresis, Polyacrylamide Gel
  • DNA Repair
  • DNA
 

Citation

APA
Chicago
ICMJE
MLA
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Tano, K., Shiota, S., Remack, J. S., Brent, T. P., Bigner, D. D., & Mitra, S. (1991). The origin of O6-methylguanine-DNA methyltransferase in Chinese hamster ovary cells transfected with human DNA. Mutat Res, 255(2), 175–182. https://doi.org/10.1016/0921-8777(91)90051-p
Tano, K., S. Shiota, J. S. Remack, T. P. Brent, D. D. Bigner, and S. Mitra. “The origin of O6-methylguanine-DNA methyltransferase in Chinese hamster ovary cells transfected with human DNA.Mutat Res 255, no. 2 (September 1991): 175–82. https://doi.org/10.1016/0921-8777(91)90051-p.
Tano K, Shiota S, Remack JS, Brent TP, Bigner DD, Mitra S. The origin of O6-methylguanine-DNA methyltransferase in Chinese hamster ovary cells transfected with human DNA. Mutat Res. 1991 Sep;255(2):175–82.
Tano, K., et al. “The origin of O6-methylguanine-DNA methyltransferase in Chinese hamster ovary cells transfected with human DNA.Mutat Res, vol. 255, no. 2, Sept. 1991, pp. 175–82. Pubmed, doi:10.1016/0921-8777(91)90051-p.
Tano K, Shiota S, Remack JS, Brent TP, Bigner DD, Mitra S. The origin of O6-methylguanine-DNA methyltransferase in Chinese hamster ovary cells transfected with human DNA. Mutat Res. 1991 Sep;255(2):175–182.
Journal cover image

Published In

Mutat Res

DOI

ISSN

0027-5107

Publication Date

September 1991

Volume

255

Issue

2

Start / End Page

175 / 182

Location

Netherlands

Related Subject Headings

  • Transfection
  • Transcription, Genetic
  • Oncology & Carcinogenesis
  • O(6)-Methylguanine-DNA Methyltransferase
  • Nucleic Acid Hybridization
  • Methyltransferases
  • Humans
  • Electrophoresis, Polyacrylamide Gel
  • DNA Repair
  • DNA