A5047771497- Telomeres, Telomerase, and Senescence
- DNA Repair Mechanisms
- CRISPR and Genetic Engineering
- Genetics, Aging, and Longevity in Model Organisms
- Fungal and yeast genetics research
- Genomics and Chromatin Dynamics
- RNA and protein synthesis mechanisms
- Nuclear Structure and Function
- Microtubule and mitosis dynamics
- Genetic factors in colorectal cancer
- Plant Virus Research Studies
Newcastle University
2004-2023
Newcastle Hospitals - Campus for Ageing and Vitality
2011
Centre for Life
2009-2011
University of Manchester
2002-2006
North Tyneside General Hospital
2005-2006
University of Newcastle Australia
2005
We have examined the role of checkpoint pathways in responding to a yku70Delta defect budding yeast. show that CHK1, MEC1, and RAD9 genes are required for efficient cell cycle arrest mutants cultured at 37 degrees C, whereas RAD17, RAD24, MEC3, DDC1, DUN1 play insignificant roles. establish is associated with increasing levels single-stranded DNA subtelomeric Y' regions, find mismatch repair-associated EXO1 gene both ssDNA generation mutants. In contrast, MRE11 not generation. The behavior...
It is generally assumed that there are only two ways to maintain the ends of chromosomes in yeast and mammalian nuclei: telomerase recombination. Without recombination, cells enter senescence, a state permanent growth arrest. We found decisive role preventing senescent budding from dividing played by Exo1 nuclease. In absence Exo1, telomerase- recombination-defective can resume cell cycle progression, despite degradation telomeric regions many chromosomes. As progresses toward internal...
To better understand telomere biology in budding yeast, we have performed systematic suppressor/enhancer analyses on yeast strains containing a point mutation the essential capping gene CDC13 (cdc13-1) or null DNA damage response and YKU70 (yku70Δ). We Quantitative Fitness Analysis (QFA) thousands of mutations affecting telomere-capping proteins combination with library deletion mutations. perform QFA, typically inoculate 384 separate cultures onto solid agar plates monitor growth each...
Cells accumulate single-stranded DNA (ssDNA) when telomere capping, replication, or repair is impeded. This accumulation leads to cell cycle arrest through activating the DNA–damage checkpoints involved in cancer protection. Hence, ssDNA could be an anti-cancer mechanism. However, has above a certain threshold activate checkpoints. What determines this checkpoint-activation important, yet unanswered question. Here we identify Rif1 (Rap1-Interacting Factor 1) as threshold-setter. Following...
Telomerase-defective budding yeast cells escape senescence by using homologous recombination to amplify telomeric or subtelomeric structures.Similarly, human that enter can use for telomere maintenance, when telomerase cannot be activated.Although proteins required generate telomerase-independent survivors have been intensively studied, little is known about the nucleases substrates recombination.Here we demonstrate Exo1 exonuclease an initiator of process allows and become immortal in...
Telomeres are essential features of linear genomes that crucial for chromosome stability. Telomeric DNA is usually replenished by telomerase. Deletion genes encoding telomerase components leads to telomere attrition with each cycle replication, eventually causing cell senescence or death. In the Saccharomyces cerevisiae strain W303, telomerase-null populations bypass and, unless EXO1 also deleted, this survival RAD52 dependent. Unexpectedly, we found S. S288C could survive removal and at a...
Telomere attrition is linked to cancer, diabetes, cardiovascular disease and aging. This because telomere losses trigger further genomic modifications, culminating with loss of cell function malignant transformation. However, factors regulating the transition from cells short telomeres, profoundly altered genomes, are little understood. Here, we use budding yeast engineered lack telomerase other forms maintenance, screen for such factors. We show that initially, different DNA damage...
Pulsed-field gel electrophoresis (PFGE) can be used to separate the 16 budding yeast chromosomes on basis of size. Here we describe a detailed, practical protocol that will allow novice perform informative PFGE experiments. We first culture prior analysis, along with details embedding cells in agarose before removal cell walls. then detail procedure remove protein and RNA from how naked are loaded into gels being subjected electrophoresis. Finally, separated visualized photographed.
Abstract Telomerase-defective budding yeast cells escape senescence by using homologous recombination to amplify telomeric or subtelomeric structures. Similarly, human that enter can use for telomere maintenance, when telomerase cannot be activated. Although proteins required generate telomerase-independent survivors have been intensively studied, little is known about the nucleases substrates recombination. Here we demonstrate Exo1 exonuclease an initiator of process allows and become...
Replicative senescence is a permanent cell cycle arrest in response to extensive telomere shortening. To understand the mechanisms behind arrest, we screened for factors affecting replicative budding yeast lacking elongation pathways. Intriguingly, found that DNA polymerase epsilon (Pol ε) acts synergistically with Exo1 nuclease maintain senescence. In contrast, Pol ε-associated checkpoint and replication protein Mrc1 facilitates escape from this paradox, which DNA-synthesizing cooperate...
Abstract Inverted chromosome duplications or palindromes are linked with genetic disorders and malignant transformation. They considered by-products of DNA double-strand break (DSB) repair: the homologous recombination (HR) nonhomologous end joining (NHEJ). Palindromes near ends often triggered by telomere losses. An important question is to what extent their formation depends upon DSB repair mechanisms. Here we addressed this using yeast genetics comparative genomic hybridization. We...
It is generally accepted that cells with extensive, un-repaired DNA damage canescape cell cycle arrest only by disabling checkpoint pathways and they usuallyperish, after several divisions, presumably due to catastrophic events on theirchromosomes. Our recently discovered PAL-mechanism opens a new perspective,that some eukaryotic short chromosome ends (telomeres), usually detectedas damage, can escape permanent (senescence) under specialconditions, despite having intact checkpoints even...
Rif1 mediates telomere length, DNA replication, and damage responses in budding yeast. Previous work identified several posttranslational modifications of Rif1, however none these was shown to mediate the molecular or cellular damage, including damage. We searched for such using immunoblotting methods cdc13-1 tlc1Δ models found that is phosphorylated during serines 57 110 within a novel phospho-gate domain (PGD) are important this modification, cells. The phosphorylation appeared inhibit its...
Damaged DNA can be repaired by removal and re-synthesis of up to 30 nucleotides during base or nucleotide excision repair. An important question is what happens when many more are removed, resulting in long single-stranded (ssDNA) lesions. Such lesions appear on chromosomes telomere damage, double strand break repair after the UV damage stationary phase cells. Here, we show that lesions, formed at dysfunctional telomeres budding yeast, re-synthesized cells removed from telomere-damaging...