Abstract
Mammalian telomeres end in single-stranded, G-rich 3′ overhangs resulting from both the "end-replication problem" (the inability of DNA polymerase to replicate the very end of the telomeres) and postreplication processing. Telomeric G-rich overhangs are precisely defined in ciliates; the length and the terminal nucleotides are fixed. Human telomeres have very long overhangs that are heterogeneous in size (35-600 nt), indicating that their processing must differ in some respects from model organisms. We developed telomere-end ligation protocols that allowed us to identify the terminal nucleotides of both the C-rich and the G-rich telomere strands. Up to ∼80% of the C-rich strands terminate in CCAATC-5′, suggesting that after replication a nuclease with high specificity or constrained action acts on the C strand. In contrast, the G-terminal nucleotide was less precise than Tetrahymena and Euplotes but still had a bias that changed as a function of telomerase expression.
Original language | English (US) |
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Pages (from-to) | 131-138 |
Number of pages | 8 |
Journal | Molecular cell |
Volume | 18 |
Issue number | 1 |
DOIs | |
State | Published - Apr 1 2005 |
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology