Inhibition of replicon cluster ligation into chromosomal DNA at elevated temperatures
✍ Scribed by Raymond L. Warters; Bradley W. Lyons
- Publisher
- John Wiley and Sons
- Year
- 1990
- Tongue
- English
- Weight
- 848 KB
- Volume
- 142
- Category
- Article
- ISSN
- 0021-9541
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
The rate limiting enzymatic step for DNA replication in HeLa cells incubated at 43.5°C v/as the ligation of clusters of replicons into the cell's genome. At 43.5° the reciprocal slope for inhibition of DNA chain (replicon) initiation, or of the ligation of replicon clusters into the genome, was 18 or 7 min, respectively. The failure of replicon clusters to be ligated into chromosomal DNA was not a consequence of the failure of histone proteins to be deposited onto replicating DNA, or of chromatin replicated at 43.5°C to be organized into fully condensed chro‐matin. In addition it was not due to the failure of fully active topoisomerase II to be deposited at a normal frequency along replicating chromatin DNA. The failure of replicon clusters to be ligated into the genome resulted in the persistence of single, but not double, DNA strand breaks in the cell's genome 24 hours after cell heating.