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Sidarava, V.

Publications and source records attributed to Sidarava, V..

2 recordsLinked to original sources

Inherited long telomeres induce a genome-wide transcriptional response in budding yeast

Eukaryotes typically maintain telomere length within a defined range. While short telomeres are known to activate DNA damage responses and limit cell proliferation, long telomeres are associated with extended proliferative capacity. The broader cellular consequences of long telomeres are comparatively less well understood. In budding yeast Saccharomyces cerevisiae, long telomeres have been shown to influence gene expression at specific loci, but whether long telomeres affect transcription genome-wide has not been reported. Here, we analysed transcriptomes in a lineage that inherited long telomeres (originally due to a rif2{Delta} mutation). Transcriptomes were assessed over two rounds of mitosis and meiosis in the absence of the rif2{Delta} mutation. We show that strains with long telomeres exhibit a distinct gene expression profile, including upregulation of membrane transporters and downregulation of a smaller subset of genes. Both up- and down-regulated genes were distributed across the genome, arguing against a purely telomere-proximal effect on gene expression. Affected genes were enriched for Rap1 binding sites, consistent with a model in which long telomeres sequester telomere-associated transcriptional regulators, such as Rap1, and thereby affect gene expression at non-telomeric binding sites for these regulators. Accordingly, the magnitude of transcriptional changes was greatest in strains with the longest telomeres. Together, our findings demonstrate that long telomeres induce a genome-wide transcriptional response that can accompany inherited long telomeres across generations. Similar effects of long telomeres are likely to occur in other eukaryotes, including humans, where long telomeres are associated with disease. Article summaryTelomeres protect chromosome ends, and their length is tightly regulated. While short telomeres are known to be harmful, the effects of long telomeres are less well understood. Using budding yeast, we show that inherited long telomeres alter the expression of dozens of genes across the genome, particularly membrane transporters. These changes are consistent with a model in which long telomeres sequester regulatory proteins away from other loci. Our findings may have broader implications in more complex organisms, including humans.

genetics↗

Long telomere inheritance through budding yeast sexual cycles

The ends of linear eukaryotic chromosomes are protected from being recognized as DNA double-strand breaks by telomeres, containing repetitive DNA sequences which bind specific proteins. In humans, mutations in telomere regulatory genes lead to short or long telomere syndromes. These syndromes often show genetic anticipation, where disease has earlier onset and a more severe manifestation in each new generation. Later generations inherit not only the mutation affecting telomere length, but also abnormal length telomeres. Many aspects of telomere length homeostasis are conserved between mammals and yeast. Here we explored telomere length inheritance patterns through the sexual cycle in yeast. Analysis of single telomeres, rather than bulk telomeres, shows that if haploid yeast with short telomeres mate with wild-type yeast creating diploids, short telomere lengths rapidly normalize (within 30 cell divisions). However, long telomeres inherited from one parent can persist for more than 200 mitotic cell divisions. Long telomere can also be transmitted through more than one round of meiosis, independently of mutations that cause long telomeres. These patterns, along with haploinsufficiency effects, show that even in yeast there is a complex relationship between telomere length, telomere length inheritance, and mutations that affect telomere length. Our findings may have implications for families affected by telomere syndromes. Article summaryTelomeres protect the ends of chromosomes from DNA damage responses. In humans, mutations causing short or long telomeres, lead to inherited disease syndromes, often showing evidence of genetic anticipation. Here we show that in budding yeast, long telomeres can be transmitted through several generations in the absence of mutations causing the long telomere phenotype. Therefore, even in a simple single-celled eukaryotic organism, complex patterns of telomere length inheritance occur. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=100 SRC="FIGDIR/small/658123v1_ufig1.gif" ALT="Figure 1"> View larger version (12K): org.highwire.dtl.DTLVardef@462226org.highwire.dtl.DTLVardef@6bfc51org.highwire.dtl.DTLVardef@182313corg.highwire.dtl.DTLVardef@6e84f9_HPS_FORMAT_FIGEXP M_FIG C_FIG

genetics↗