Detection of replication initiation by a replicon family in DNA of synchronized pea (Pisum sativum) root cells using benzoylated naphthoylated DEAE-cellulose chromatography
✍ Scribed by J. Hof; S. S. Lamm; C. A. Bjerknes
- Book ID
- 104614089
- Publisher
- Springer
- Year
- 1987
- Tongue
- English
- Weight
- 722 KB
- Volume
- 9
- Category
- Article
- ISSN
- 0167-4412
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✦ Synopsis
Fractionated replicating DNA from pea was obtained from both synchronized cells just starting replication and from carbohydrate-starved cells ending replication. Benzoylated naphthoylated DEAE-cellulose chromatography of pulse-labeled DNA digested with &OR I gave evidence that a family of replicons initiated replication 45 to 60 min after synchronized cells were released from the Gt/S phase boundary. DNA from cells labeled in late S phase, on the other hand, showed no signs of additional replication initiations before entering G2 phase. Results with DNA from both early and late S phase cells comply with a model based on the premise that with short pulses of [3H]-thymidine the isotope is localized at replication forks and that longer pulses label both replication forks and recently replicated segments of double-stranded DNA. The model applies only to DNA subjected to fragmentation before chromatography.
The results also suggest that benzoylated naphthoylated DEAE-cellulose chromatography is a useful means to isolate origins and replication forks from synchronized plant cells.