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Updated: Jul 11, 2025
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Direct Restart of a Replication Fork Stalled by a Head-On RNA Polymerase
Published on: April 29, 2010
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CST-Polymeraseα-primase solves a second telomere end-replication problem
Hiroyuki Takai1, Valentina Aria2, Pamela Borges1
1Laboratory for Cell Biology and Genetics, Rockefeller University, New York, USA.
Biorxiv : the Preprint Server for Biology
|November 14, 2023
Summary
Telomere shortening is caused by two replication problems. Telomerase maintains the G-strand, while CST-Polymeraseα(Polα)-primase handles the C-strand to prevent telomere attrition.
Area of Science:
- Molecular Biology
- Genetics
- Cell Biology
Background:
- Telomeres protect chromosome ends from degradation and fusion.
- Telomere shortening occurs due to the end-replication problem during DNA synthesis.
- Telomerase counteracts shortening by adding repeats to the G-rich strand.
Approach:
- Investigated a second end-replication problem affecting the C-rich strand.
- Utilized in vitro assays to analyze lagging-strand synthesis limitations.
- Examined telomere length dynamics in cells lacking CST-Polymeraseα(Polα)-primase.
Key Points:
- Lagging-strand synthesis is incomplete, leaving a gap near the telomere end.
- CST-Polymeraseα(Polα)-primase fills this gap, maintaining C-strand length.
- Cells lacking CST-Polα-primase exhibit significant C-strand shortening at lagging ends.
Conclusions:
- Canonical DNA replication presents two distinct telomere end-replication challenges.
- Telomerase is essential for G-strand maintenance.
- CST-Polymeraseα(Polα)-primase is crucial for C-strand maintenance, preventing telomere loss.
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