1. Coordinate regulation of G- and C strand length during new telomere synthesis.
- Author
-
Fan X and Price CM
- Subjects
- Animals, Aphidicolin pharmacology, Base Composition, Cloning, Molecular, Cytosine, DNA Replication drug effects, DNA, Protozoan chemistry, DNA-Directed DNA Polymerase physiology, Enzyme Inhibitors pharmacology, Euplotes cytology, Guanine, Nucleic Acid Synthesis Inhibitors, Sequence Analysis, DNA, Telomerase metabolism, Telomere chemistry, DNA, Protozoan biosynthesis, Euplotes genetics, Telomere metabolism
- Abstract
We have used the ciliate Euplotes to study the role of DNA polymerase in telomeric C strand synthesis. Euplotes provides a unique opportunity to study C strand synthesis without the complication of simultaneous DNA replication because millions of new telomeres are made at a stage in the life cycle when no general DNA replication takes place. Previously we showed that the C-strands of newly synthesized telomeres have a precisely controlled length while the G-strands are more heterogeneous. This finding suggested that, although synthesis of the G-strand (by telomerase) is the first step in telomere addition, a major regulatory step occurs during subsequent C strand synthesis. We have now examined whether G- and C strand synthesis might be regulated coordinately rather than by two independent mechanisms. We accomplished this by determining what happens to G- and C strand length if C strand synthesis is partially inhibited by aphidicolin. Aphidicolin treatment caused a general lengthening of the G-strands and a large increase in C strand heterogeneity. This concomitant change in both the G- and C strand length indicates that synthesis of the two strands is coordinated. Since aphidicolin is a very specific inhibitor of DNA pol alpha and pol delta, our results suggest that this coordinate length regulation is mediated by DNA polymerase.
- Published
- 1997
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