Article

Abstract

• Telomeres are nucleoprotein complexes that cap and protect the ends of linear chromosomes. In humans, telomeres end in 50–300 nt of G-rich single-stranded DNA (ssDNA) overhangs. Protection of telomeres 1 (POT1) binds with nanomolar affinity to the ssDNA overhangs and forms a dimer with another telomere-end binding protein called TPP1. Whereas most previous studies utilized telomeric oligonucleotides comprising single POT1–TPP1 binding sites, here, we examined 72- to 144-nt tracts of telomeric DNA containing 6–12 POT1–TPP1 binding sites. Using electrophoretic mobility gel shift assays, size-exclusion chromatography, and electron microscopy, we analyzed telomeric nucleoprotein complexes containing POT1 alone, POT1–TPP1, and a truncated version of POT1 (POT1-N) that maintains its DNA-binding domain. The results revealed that POT1-N and POT1–TPP1 can completely coat long telomeric ssDNA substrates. Furthermore, we show that ssDNA coated with human POT1–TPP1 heterodimers forms compact, potentially ordered structures.

Creator

• Taatjes, Dylan J.
• Cech, Thomas R.
• Taylor, Derek J.
• Podell, Elaine R.

Date Issued

• 2011-07-01

Academic Affiliation

• Chemical and Biological Engineering

Journal Title

• Journal of Molecular Biology

Journal Issue/Number

• 1

Journal Volume

• 410

File Extent

• 10-17

Subject

• telomeres. telomerase
• POT1
• TPP1

Last Modified

• 2019-12-05

Resource Type

• Article

Rights Statement

• In Copyright

DOI

• 10.1016/j.jmb.2011.04.049

Language

• English [eng]

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