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Does capacity of DNA replication change during in vitro ageing?
Experimental Cell Research
|February 1, 1985
Summary
Cellular aging in human fibroblasts does not impair DNA replication machinery. Instead, altered DNA replication regulation may cause increased non-cycling cells during prolonged culturing.
Area of Science:
- Cell Biology
- Molecular Biology
- Gerontology
Background:
- In vitro aging of human diploid fibroblasts previously showed no change in DNA chain elongation rates.
- Further investigation is needed to understand other aspects of DNA replication during cellular aging.
Purpose of the Study:
- To investigate DNA synthesis rate, replicon size, and cell cycle phase durations during in vitro aging.
- To determine if impaired DNA replication capacity contributes to reduced proliferation in aged cells.
Main Methods:
- Assessed tritiated thymidine incorporation to measure net DNA synthesis rate.
- Analyzed replicon size and cell cycle phase durations in cultured human diploid fibroblasts at different population doubling levels.
Main Results:
- Net DNA synthesis rate, replicon size, and S phase duration remained unchanged during in vitro aging.
- No decline in the intrinsic capacity of the DNA replication machinery was observed.
Conclusions:
- Reduced proliferation in aged human fibroblasts is unlikely due to a decline in DNA replication ability.
- Changes in DNA replication regulatory systems, rather than the machinery itself, may lead to an increase in non-cycling cells.