Open AccessTelomeric circles: universal players in telomere maintenance?
Author(s) -
Ľubomír Tomáška,
Jozef Nosek,
Juraj Kramara,
Jack D. Griffith
Publication year - 2009
Publication title -
nature structural and molecular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 9.448
H-Index - 270
eISSN - 1545-9993
pISSN - 1545-9985
DOI - 10.1038/nsmb.1660
Subject(s) - telomere , telomerase , retrotransposon , biology , genome , telomere binding protein , dna , genetics , homologous recombination , palindrome , computational biology , dna binding protein , transposable element , gene , transcription factor
To maintain linear DNA genomes, organisms have evolved numerous means of solving problems associated with DNA ends (telomeres), including telomere-associated retrotransposons, palindromes, hairpins, covalently bound proteins and the addition of arrays of simple DNA repeats. Telomeric arrays can be maintained through various mechanisms such as telomerase activity or recombination. The recombination-dependent maintenance pathways may include telomeric loops (t-loops) and telomeric circles (t-circles). The potential involvement of t-circles in telomere maintenance was first proposed for linear mitochondrial genomes. The occurrence of t-circles in a wide range of organisms, spanning yeasts, plants and animals, suggests the involvement of t-circles in many phenomena including the alternative-lengthening of telomeres (ALT) pathway and telomere rapid deletion (TRD). In this Perspective, we summarize these findings and discuss how t-circles may be related to t-loops and how t-circles may have initiated the evolution of telomeres.