Drosophila embryos provide a rich source of replicative enzymes. Also, the duration of 2 hour embryo DNA synthesis phase of the cell cycle is approximately 6-fold shorter than the more regulated 9 hour embryo S phase. Thus, Drosophila embryos are a good system in which to explore the mechanisms and regulation of DNA replication. Early stage, 2 hour embryos contain at least two distinct DNA polymerases, DNA polymerase α and δ, as determined by associated enzymatic activities (DNA primase and 3'-5' exonuclease), inhibitor studies, immunologic reactivity, and processivity measurements. The observation that a δ-type enzyme with an inherent 3'-5' exonuclease activity is present in Drosophila embryos is a novel observation, and may have important implications for maintaining the fidelity of embryonic DNA synthesis. Both 2 hour and 9 hour embryos contained similar replicative activities. The enzymes which copurified with 2 hour and 9 hour DNA polymerases include a DNA primase activity with DNA polymerase α; and a 3'-5' exonuclease, 5'-3' exonuclease, and DNA ligase activities with DNA polymerase δ. The association of these activities suggests that DNA polymerase α-associated enzymes may initiate Okazaki fragments, which would then be elongated and ligated by the DNA polymerase δ-associated group.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/185786 |
| Date | January 1992 |
| Creators | Peck, Vickie Marie. |
| Contributors | Cress, Anne E., Hendrix, Mary J.C., Bernstein, Harris, Dieckmann, Carol |
| Publisher | The University of Arizona. |
| Source Sets | University of Arizona |
| Language | English |
| Detected Language | English |
| Type | text, Dissertation-Reproduction (electronic) |
| Rights | Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. |
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