Computational Biology
@ Comenius University in Bratislava

Brona Brejova, Viktoria Hodorova, Hana Lichancova, Askar Gafurov, Dominik Bujna, Filip Brazdovic, Filip Cervenak, Tomas Petrik, Eva Hegedusova, Michaela {Forgacova Jakubkova}, Martina Nebohacova, Lubomir Tomaska, Matthias Sipiczki, Tomas Vinar, Jozef Nosek. Noncanonical chromosomal-end-specific telomeric repeat arrays in naturally telomerase-negative yeasts. Nucleic Acids Research, 54(10). 2026.

Download preprint: not available

Download from publisher: not available

Related web page: not available

Bibliography entry: BibTeX

Abstract:

In most eukaryotes, chromosomal DNA terminates with tandem repeats of a short 
G-rich motif, such as the canonical TTAGGG sequence. The arrays of telomeric 
repeats are maintained by telomerase or by alternative lengthening of telomeres 
(ALT). Here, we report that nuclear chromosomes of several basidiomycetous yeasts 
classified into the order Microstromatales carry unusual telomeres. We 
demonstrate that instead of TTAGGG-like repeats these telomeres are composed of 
unique, tandemly repeated motifs, which are in most cases specific to a 
particular chromosomal end. In contrast to other basidiomycetes, the 
Microstromatales genomes lack orthologs coding for the telomerase catalytic 
subunit Est2 and a shelterin component Tpp1 indicating that noncanonical 
telomeric repeats are maintained by a telomerase-independent mechanism. We 
hypothesize that in a common ancestor of Microstromatales the loss of telomerase 
and Tpp1 was compensated by activation of an ALT-like mechanism, which promoted 
amplification of various motifs and formation of distinct telomeric repeat arrays 
at most chromosomal ends.