Sep 1, 1989

Maintenance of DNA methylation level in SV40-infected human fibroblasts during their in vitro limited proliferative life span

Experimental Cell Research
T MatsumuraR Holliday


Methylation level as expressed by the molar ratio of 5-methylcytosine content to the combined content of cytosine and 5-methylcytosine was determined by HPLC and uv adsorption of cellular DNA extracted from SV40-infected and pretransformed MRC-5 human diploid fibroblasts (HDFs) during their limited in vitro life span. The level decreased slightly during early passages, and then was maintained within a certain range in the subsequent pretransformed stage of serial passages. When HDFs were treated with 5-aza-2'-deoxycytidine (5-aza-CdR) at an effective concentration shortly after the SV40 infection, the level decreased and then increased or was maintained again within a certain range in the subsequent pretransformed state. The proliferative life span potential of SV40-infected HDFs was not significantly decreased by the 5-aza-CdR treatment. These results are in contrast to the established observations for uninfected HDFs, that methylation level decreases during serial passages, and that, after treatment with 5-aza-CdR, the level, as well as the proliferative life span, is decreased in comparison to untreated populations. These results show that SV40-infected pretransformed HDFs are in an intermediate state between normal finite g...Continue Reading

Mentioned in this Paper

Specimen Type - Fibroblasts
Protein Methylation
Simian virus 40
Maintenance of DNA Methylation
Cell Proliferation
5-Methylcytosine Monohydrochloride
Cell Division Phases

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