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Molecular characterization of Chlamydomonas reinhardtii telomeres and telomerase mutants

TitleMolecular characterization of Chlamydomonas reinhardtii telomeres and telomerase mutants
Publication TypeJournal Article
Year of Publication2019
AuthorsEberhard, S, Valuchova, S, Ravat, J, Fulnecek, J, Jolivet, P, Bujaldon, S, Lemaire, SD, Wollman, FA, Teixeira, MT, Riha, K, Xu, Z
JournalLife Sci Alliance
Date PublishedJun
ISBN Number2575-1077 (Electronic)2575-1077 (Linking)
KeywordsAmino Acid Sequence, Base Sequence, Chlamydomonas reinhardtii/*genetics, Genetic Variation, Polymorphism, Restriction Fragment Length, Repetitive Sequences, Nucleic Acid, Telomerase/chemistry/*genetics/metabolism, Telomere Homeostasis, Telomere Shortening, Telomere/*genetics

Telomeres are repeated sequences found at the end of the linear chromosomes of most eukaryotes and are required for chromosome integrity. Expression of the reverse-transcriptase telomerase allows for extension of telomeric repeats to counteract natural telomere shortening. Although Chlamydomonas reinhardtii, a photosynthetic unicellular green alga, is widely used as a model organism in photosynthesis and flagella research, and for biotechnological applications, the biology of its telomeres has not been investigated in depth. Here, we show that the C. reinhardtii (TTTTAGGG)n telomeric repeats are mostly nondegenerate and that the telomeres form a protective structure, with a subset ending with a 3' overhang and another subset presenting a blunt end. Although telomere size and length distributions are stable under various standard growth conditions, they vary substantially between 12 genetically close reference strains. Finally, we identify CrTERT, the gene encoding the catalytic subunit of telomerase and show that telomeres shorten progressively in mutants of this gene. Telomerase mutants eventually enter replicative senescence, demonstrating that telomerase is required for long-term maintenance of telomeres in C. reinhardtii.

Short TitleLife science alliance