Project description:Transposon insertion site sequencing (TIS) is a powerful method for associating genotype to phenotype. However, all TIS methods described to date use short nucleotide sequence reads which cannot uniquely determine the locations of transposon insertions within repeating genomic sequences where the repeat units are longer than the sequence read length. To overcome this limitation, we have developed a TIS method using Oxford Nanopore sequencing technology that generates and uses long nucleotide sequence reads; we have called this method LoRTIS (Long Read Transposon Insertion-site Sequencing). This experiment data contains sequence files generated using Nanopore and Illumina platforms. Biotin1308.fastq.gz and Biotin2508.fastq.gz are fastq files generated from nanopore technology. Rep1-Tn.fastq.gz and Rep1-Tn.fastq.gz are fastq files generated using Illumina platform. In this study, we have compared the efficiency of two methods in identification of transposon insertion sites.
Project description:The Rif1 protein negatively regulates telomeric TG repeat length in the budding yeast S. cerevisiae, but how it prevents telomere over-extension is unknown. Rif1 was recently shown to control DNA replication by acting as a Protein Phosphatase 1 (PP1)-targeting subunit. Therefore we investigated whether Rif1 controls telomere length by targeting PP1 activity. We find that a Rif1 mutant that cannot interact with PP1 causes a long-telomere phenotype, similar to that of rif1∆ cells. Compromised PP1 function also causes telomere extension. Tethering PP1 at a specific telomere partially substitutes for Rif1 in limiting TG repeat length, confirming the importance of PP1 in telomere length control. Ablating Rif1-PP1 interaction leads to precocious activation of telomere-proximal replication origins and aberrantly early telomere replication. However, we find that Rif1 still limits telomere length even if nearby replication origins are deleted, indicating that effects of Rif1 on telomere length are not mediated through replication timing. Instead we find that, even at a telomere created after DNA synthesis during a mitotic block, Rif1-PP1 interaction is required to suppress telomere lengthening and prevent inappropriate recruitment of Tel1 kinase. Overall, our results show that Rif1 controls telomere length by recruiting PP1 to directly suppress telomerase-mediated TG repeat lengthening.
Project description:Telomere DNA length is a complex trait controlled both by multiple loci and environmental factors. Even though the use of telomere DNA length measurement, as a method of assessing stress accumulation and predicting how this will influence survival, is currently being studied in numerous human cohort studies, the importance of telomere length for stress response in ecological studies remains at its infancy. Here, we investigated the telomere changes occurring in the symbiotic coral Stylophora pistillata that has experienced a continuous darkness over 6 months. This stress condition led to the loss of its symbionts, as what is also observed when bleaching occurs in the field at a large-scale due to climate changes and anthropogenic activities, threatening the worldwide reef ecosystem. We found that the continuous darkness condition was associated to telomere DNA length shortening and a downregulation of the expression of the telomere-associated protein POT2. These results pave the way for future studies on the role of telomere in coral stress response and the importance of telomere dysregulation in endangered coral species
2021-09-20 | GSE171268 | GEO
Project description:Telomere measurement by long-read sequencing
Project description:Telomere length heterogeneity in various cell types including stem cells and cancer cells has been recognized. Cell heterogeneity also is found in pluripotent stem cells such as embryonic stem cells (ESCs). The implication and mechanisms underlying the heterogeneity remain to be defined. We have optimized a robust method that can simultaneously measure telomere length coupled with RNA-sequencing analysis (scT&R-seq) in the same human ES cell. Using this method, we show that telomere length varies with pluripotency state. Long telomere hESCs highly express TERF1/TRF1 as well as ZFP42/REX1, PRDM14 and NANOG for naïve pluripotency, in contrast to short telomere hESCs. hESCs express high telomerase activity as expected, and ubiquitously express NOP10 and DKC1, stabilizing components of telomerase complexes, regardless of telomere lengths. Moreover, new candidate genes such as MELK, MSH6 and UBQLN1 cluster with long telomeres and pluripotency network. Notably, short telomere hESCs exhibit higher oxidative phosphorylation primed for lineage differentiation, whereas long telomere hESCs show elevated glycolysis, another key feature for naïve pluripotency. Our data further suggest that telomere length is implicated in metabolism activity and pluripotency state of hESCs. Single cell analysis of telomere and RNA-sequencing can be exploited to further understand the molecular mechanisms of telomere heterogeneity.
Project description:Tuberous sclerosis complex (TSC) is a relatively common autosomal dominant disorder characterized by multiple dysplastic organ lesions and neuropsychiatric symptoms, caused by loss-of-function mutation of either TSC1 or TSC2. Target-capture full-length double-stranded cDNA sequencing using long-read sequencer Nanopore (Nanopore Long-read Target Sequencing) revealed that the various kinds of the TSC1 and TSC2 full-length transcripts and the novel intron retention transcripts of TSC2 in TSC patient. Our results indicate that the Nanopore Long-read Target Sequencing is useful for the detection of mutations and confers information on the full-length alternative splicing transcripts for the genetic diagnosis.
Project description:Telomeres and the protein/RNA complexes involved in maintaining them are rapidly evolving systems across eukaryotes. Using two Saccharomyces species, S. cerevisiae and S. bayanus, we provide evidence that the telomere systems of these two closely related yeasts have evolved significantly apart and that the gene in one species can not maintain the set-point of telomere length of the other species in the hybrid.
Project description:Telomeres and the protein/RNA complexes involved in maintaining them are rapidly evolving systems across eukaryotes. Using two Saccharomyces species, S. cerevisiae and S. bayanus, we provide evidence that the telomere systems of these two closely related yeasts have evolved significantly apart and that the gene in one species can not maintain the set-point of telomere length of the other species in the hybrid. Each array has co-hybridized RNA vs DNA for the indicated species (BB9=S. bayanus, CC5=S. cerevisiae) or hybrid (BC11). The cultures for RNA preparation were grown to midlog phase at the indicated temperature.