CST–Polα/Primase: the second telomere maintenance machine
- Corresponding author: delange{at}rockefeller.edu
Abstract
It has been known for decades that telomerase extends the 3′ end of linear eukaryotic chromosomes and dictates the telomeric repeat sequence based on the template in its RNA. However, telomerase does not mitigate sequence loss at the 5′ ends of chromosomes, which results from lagging strand DNA synthesis and nucleolytic processing. Therefore, a second enzyme is needed to keep telomeres intact: DNA polymerase α/Primase bound to Ctc1–Stn1–Ten1 (CST). CST–Polα/Primase maintains telomeres through a fill-in reaction that replenishes the lost sequences at the 5′ ends. CST not only serves to maintain telomeres but also determines their length by keeping telomerase from overelongating telomeres. Here we discuss recent data on the evolution, structure, function, and recruitment of mammalian CST–Polα/Primase, highlighting the role of this complex and telomere length control in human disease.
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Article published online ahead of print. Article and publication date are online at http://www.genesdev.org/cgi/doi/10.1101/gad.350479.123.
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Freely available online through the Genes & Development Open Access option.
This article, published in Genes & Development, is available under a Creative Commons License (Attribution-NonCommercial 4.0 International), as described at http://creativecommons.org/licenses/by-nc/4.0/.