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1.
BJPsych Open ; 9(3): e96, 2023 May 26.
Article in English | MEDLINE | ID: mdl-37232106

ABSTRACT

BACKGROUND: Brain in Hand (BIH) is a UK-based digital self-support system for managing anxiety and social functioning. AIMS: To identify the impact of BIH on the psychological and social functioning of adults with autism. METHOD: Adults with diagnosed or suspected DSM-5 (level 1) autism, identified by seven NHS autism services in England and Wales, were recruited for a 12-week prospective mixed-methods cohort study. The primary quantitative outcome measures were the Health of the Nation Outcome Scales for People with Learning Disabilities (HONOS-LD) and the Hospital Anxiety and Depression Scale (HADS). Fisher's exact test explored sociodemographic associations. Paired t-test was utilised for pre-post analysis of overall effectiveness of BIH. Multivariable linear regression models, univariable pre-post analysis, Wilcoxon signed-rank test, logistic regression analysis, Bonferroni correction and normative analysis were used to give confidence in changes identified. A thematic analysis of semi-structured exist interviews following Braun and Clarke's six-step process of 10% of participants who completed the study was undertaken. RESULTS: Sixty-six of 99 participants completed the study. There was significant reduction in mean HONOS-LD scores, with 0.65 s.d. decrease in those who used BIH for 12 weeks. Significant positive changes were identified in HONOS-LD subdomains of 'self-injurious behaviours', 'memory and orientation', 'communication problems in understanding', 'occupation and activities' and 'problems with relationship'. A significant reduction in the anxiety, but not depression, component of the HADS scores was identified. Thematic analysis showed high confidence in BIH. CONCLUSIONS: BIH improved anxiety and other clinical, social and functioning outcomes of adults with autism.

2.
Brain ; 146(8): 3206-3220, 2023 08 01.
Article in English | MEDLINE | ID: mdl-36732296

ABSTRACT

Alzheimer's disease and related disorders feature neurofibrillary tangles and other neuropathological lesions composed of detergent-insoluble tau protein. In recent structural biology studies of tau proteinopathy, aggregated tau forms a distinct set of conformational variants specific to the different types of tauopathy disorders. However, the constituents driving the formation of distinct pathological tau conformations on pathway to tau-mediated neurodegeneration remain unknown. Previous work demonstrated RNA can serve as a driver of tau aggregation, and RNA associates with tau containing lesions, but tools for evaluating tau/RNA interactions remain limited. Here, we employed molecular interaction studies to measure the impact of tau/RNA binding on tau microtubule binding and aggregation. To investigate the importance of tau/RNA complexes (TRCs) in neurodegenerative disease, we raised a monoclonal antibody (TRC35) against aggregated tau/RNA complexes. We showed that native tau binds RNA with high affinity but low specificity, and tau binding to RNA competes with tau-mediated microtubule assembly functions. Tau/RNA interaction in vitro promotes the formation of higher molecular weight tau/RNA complexes, which represent an oligomeric tau species. Coexpression of tau and poly(A)45 RNA transgenes in Caenorhabditis elegans exacerbates tau-related phenotypes including neuronal dysfunction and pathological tau accumulation. TRC35 exhibits specificity for Alzheimer's disease-derived detergent-insoluble tau relative to soluble recombinant tau. Immunostaining with TRC35 labels a wide variety of pathological tau lesions in animal models of tauopathy, which are reduced in mice lacking the RNA binding protein MSUT2. TRC-positive lesions are evident in many human tauopathies including Alzheimer's disease, progressive supranuclear palsy, corticobasal degeneration and Pick's disease. We also identified ocular pharyngeal muscular dystrophy as a novel tauopathy disorder, where loss of function in the poly(A) RNA binding protein (PABPN1) causes accumulation of pathological tau in tissue from post-mortem human brain. Tau/RNA binding drives tau conformational change and aggregation inhibiting tau-mediated microtubule assembly. Our findings implicate cellular tau/RNA interactions as modulators of both normal tau function and pathological tau toxicity in tauopathy disorders and suggest feasibility for novel therapeutic approaches targeting TRCs.


Subject(s)
Alzheimer Disease , Neurodegenerative Diseases , Tauopathies , Humans , Mice , Animals , tau Proteins/metabolism , Alzheimer Disease/pathology , RNA/metabolism , Neurodegenerative Diseases/pathology , Detergents/metabolism , Polymerization , Tauopathies/pathology , Brain/pathology , RNA, Messenger/metabolism , Caenorhabditis elegans/metabolism , Microtubules/metabolism , Poly(A)-Binding Protein I/metabolism
3.
Hum Mol Genet ; 29(3): 495-505, 2020 02 01.
Article in English | MEDLINE | ID: mdl-31943011

ABSTRACT

Aggregates of Aß peptide and the microtubule-associated protein tau are key molecular hallmarks of Alzheimer's disease (AD). However, the interaction between these two pathologies and the mechanisms underlying disease progression have remained unclear. Numerous failed clinical trials suggest the necessity for greater mechanistic understanding in order to refine strategies for therapeutic discovery and development. To this end, we have generated a transgenic Caenorhabditis elegans model expressing both human Aß1-42 peptide and human tau protein pan-neuronally. We observed exacerbated behavioral dysfunction and age-dependent neurodegenerative changes in the Aß;tau transgenic animals. Further, these changes occurred in the Aß;tau transgenic animals at greater levels than worms harboring either the Aß1-42 or tau transgene alone and interestingly without changes to the levels of tau expression, phosphorylation or aggregation. Functional changes were partially rescued with the introduction of a genetic suppressor of tau pathology. Taken together, the data herein support a synergistic role for both Aß and tau in driving neuronal dysfunction seen in AD. Additionally, we believe that the utilization of the genetically tractable C. elegans model will provide a key resource for dissecting mechanisms driving AD molecular pathology.


Subject(s)
Amyloid beta-Peptides/adverse effects , Disease Models, Animal , Neurodegenerative Diseases/pathology , Neurons/pathology , tau Proteins/metabolism , Animals , Animals, Genetically Modified , Caenorhabditis elegans , Humans , Neurodegenerative Diseases/etiology , Neurodegenerative Diseases/metabolism , Neurons/metabolism , Phosphorylation , tau Proteins/genetics
4.
Pathobiol Aging Age Relat Dis ; 9(1): 1657768, 2019.
Article in English | MEDLINE | ID: mdl-31528297

ABSTRACT

A major obstacle for preclinical testing of Alzheimer's disease (AD) therapies is the availability of translationally relevant AD models. Critical for the validation of such models is the application of the same approaches and techniques used for the neuropathological characterization of AD. Deposition of amyloid-ß 42 (Aß42) plaques and neurofibrillary tangles containing phospho-Tau (pTau) are the pathognomonic features of AD. In the neuropathologic evaluation of AD, immunohistochemistry (IHC) is the current standard method for detection of Aß42 and pTau. Although IHC is indispensable for determining the distribution of AD pathology, it is of rather limited use for assessment of the quantity of AD pathology. We have recently developed Luminex-based assays for the quantitative assessment of Aß42 and pTau in AD brains. These assays are based on the same antibodies that are used for the IHC-based diagnosis of AD neuropathologic change. Here we report the application and extension of such quantitative AD neuropathology assays to commonly used genetically engineered AD models and to animals that develop AD neuropathologic change as they age naturally. We believe that identifying AD models that have Aß42 or pTau levels comparable to those observed in AD will greatly improve the ability to develop AD therapies. Abbreviations: Alzheimer's disease (AD); amyloid ß 42 (Aß42); phospho-Tau (pTau); immunohistochemistry (IHC).

7.
Can J Nurs Res ; 51(2): 105-115, 2019 Jun.
Article in English | MEDLINE | ID: mdl-30587004

ABSTRACT

Mothering while homeless poses significant barriers in achieving health and unique challenges while parenting without a home. The contextual processes shaping mothers' experiences of social exclusion and homelessness, and the internalized impacts on homeless mothers' lives, are reported on in this article. Critical narrative methodology was employed with 41 participants comprised of 26 mothers experiencing homelessness, and 15 service providers who provided care to mothers experiencing homelessness participated in this study. Two overarching themes were constructed: (1) internalized expectations and regulation and (2) pushing back from the margins: sources of resilience and resistance. Women showed a great deal of agency within the existing structures of exclusion; they worked, and at times fought, tirelessly for safety, housing, their children, and their human rights. They actively demonstrated their agency and resistance within the webs of exclusion they faced. In promoting health, nurses can best support mothers in many ways, such as by employing strengths-based nursing, challenging their own stigma and notions of 'good mothering', and by recognizing and challenging the often insurmountable barriers posed within the system for this population.


Subject(s)
Ill-Housed Persons , Mothers , Psychological Distance , Social Behavior , Adult , Child , Female , Humans
8.
Methods Cell Biol ; 141: 3-26, 2017.
Article in English | MEDLINE | ID: mdl-28882309

ABSTRACT

In this chapter, we describe methods for the purification of both untagged and polyhistidine-tagged tau protein. These protocols utilize a bacterial expression system to produce the tau isoform of interest, followed by heat treatment and column chromatography to separate tau from impurities. These techniques yield a biochemically pure protein with which to pursue any number of questions regarding the mechanisms of tau action.


Subject(s)
Chromatography, Affinity/methods , Histidine/metabolism , tau Proteins/isolation & purification , tau Proteins/metabolism , Histidine/chemistry , Histidine/genetics , Humans , Recombinant Proteins/genetics , Recombinant Proteins/isolation & purification , Recombinant Proteins/metabolism , tau Proteins/genetics
9.
Neurotox Res ; 32(1): 151-162, 2017 Jul.
Article in English | MEDLINE | ID: mdl-28391556

ABSTRACT

Chemotherapy-induced peripheral neuropathy (CIPN) is a common side effect of anticancer treatment with microtubule-targeted agents (MTAs). The frequency of severe CIPN, which can be dose limiting and even life threatening, varies widely among different MTAs. For example, paclitaxel induces a higher frequency of severe CIPN than does eribulin. Different MTAs also possess distinct mechanisms of microtubule-targeted action. Recently, we demonstrated that paclitaxel and eribulin differentially affect sciatic nerve axons, with paclitaxel inducing more pronounced neurodegenerative effects and eribulin inducing greater microtubule stabilizing biochemical effects. Here, we complement and extend these axonal studies by assessing the effects of paclitaxel and eribulin in the cell bodies of sciatic nerve axons, housed in the dorsal root ganglia (DRG). Importantly, the microtubule network in cell bodies is known to be significantly more dynamic than in axons. Paclitaxel induced activating transcription factor 3 expression, a marker of neuronal stress/injury. Paclitaxel also increased expression levels of acetylated tubulin and end binding protein 1, markers of microtubule stability and growth, respectively. These effects are hypothesized to be detrimental to the dynamic microtubule network within the cell bodies. In contrast, eribulin had no significant effect on any of these parameters in the cell bodies. Taken together, DRG cell bodies and their axons, two distinct neuronal cell compartments, contain functionally distinct microtubule networks that exhibit unique biochemical responses to different MTA treatments. We hypothesize that these distinct mechanistic actions may underlie the variability seen in the initiation, progression, persistence, and recovery from CIPN.


Subject(s)
Antineoplastic Agents/toxicity , Furans/therapeutic use , Ketones/therapeutic use , Paclitaxel/therapeutic use , Sciatic Neuropathy/chemically induced , Sciatic Neuropathy/pathology , Sensory Receptor Cells/drug effects , Activating Transcription Factor 3/metabolism , Animals , Cell Body , Disease Models, Animal , Female , Ganglia, Spinal/cytology , Mice , Mice, Inbred BALB C , Microtubules/metabolism , Tubulin/metabolism
10.
J Neurochem ; 137(6): 939-54, 2016 06.
Article in English | MEDLINE | ID: mdl-26953146

ABSTRACT

Despite extensive structure-function analyses, the molecular mechanisms of normal and pathological tau action remain poorly understood. How does the C-terminal microtubule-binding region regulate microtubule dynamics and bundling? In what biophysical form does tau transfer trans-synaptically from one neuron to another, promoting neurodegeneration and dementia? Previous biochemical/biophysical work led to the hypothesis that tau can dimerize via electrostatic interactions between two N-terminal 'projection domains' aligned in an anti-parallel fashion, generating a multivalent complex capable of interacting with multiple tubulin subunits. We sought to test this dimerization model directly. Native gel analyses of full-length tau and deletion constructs demonstrate that the N-terminal region leads to multiple bands, consistent with oligomerization. Ferguson analyses of native gels indicate that an N-terminal fragment (tau(45-230) ) assembles into heptamers/octamers. Ferguson analyses of denaturing gels demonstrates that tau(45-230) can dimerize even in sodium dodecyl sulfate. Atomic force microscopy reveals multiple levels of oligomerization by both full-length tau and tau(45-230) . Finally, ion mobility-mass spectrometric analyses of tau(106-144) , a small peptide containing the core of the hypothesized dimerization region, also demonstrate oligomerization. Thus, multiple independent strategies demonstrate that the N-terminal region of tau can mediate higher order oligomerization, which may have important implications for both normal and pathological tau action. The microtubule-associated protein tau is essential for neuronal development and maintenance, but is also central to Alzheimer's and related dementias. Unfortunately, the molecular mechanisms underlying normal and pathological tau action remain poorly understood. Here, we demonstrate that tau can homo-oligomerize, providing novel mechanistic models for normal tau action (promoting microtubule growth and bundling, suppressing microtubule shortening) and pathological tau action (poisoning of oligomeric complexes).


Subject(s)
Microtubules/metabolism , tau Proteins/chemistry , tau Proteins/metabolism , Amino Acid Sequence/physiology , Animals , Dimerization , Humans , Mass Spectrometry , Microscopy, Atomic Force , Models, Biological , Peptides/chemistry , Protein Binding , tau Proteins/genetics
11.
Neurotox Res ; 29(2): 299-313, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26659667

ABSTRACT

Microtubule targeting agents (MTAs) often lead to treatment limiting and life threatening side effects, including chemotherapy-induced peripheral neuropathy (CIPN). The frequency of severe CIPN varies among different MTAs. Since the microtubule binding interactions and mechanisms of action also vary among MTAs, we hypothesized that these distinct mechanisms may underlie the variability in frequency of severe CIPN. Using a two-week, maximum tolerated dose model, we morphologically and biochemically analyzed sciatic nerves from mice treated with either paclitaxel or eribulin. These drugs differ in their manner of microtubule binding and mechanisms of action and reports indicate paclitaxel also induces a higher frequency of severe CIPN than does eribulin. Morphologically, paclitaxel increased the frequency of observed signs of axon degeneration more significantly than did eribulin. Alternatively, eribulin but not paclitaxel induced occasional myelin "halo" structures. Biochemically, paclitaxel, and eribulin both induced α-tubulin expression (~1.9- and ~2.5-fold, respectively) and tubulin acetylation, a marker for microtubule stability, (~5- and ~11.7-fold, respectively). Eribulin but not paclitaxel-induced EB1 expression ~2.2-fold while paclitaxel but not eribulin mildly suppressed EB3 expression. Both EB proteins are associated with microtubule growth. Eribulin's combination of relatively mild deleterious morphological effects coupled with more potent biochemical changes promoting microtubule stability and growth in mice correlate with lower frequencies of severe CIPN in humans. We suggest that these eribulin-induced effects create a relatively stable microtubule network that compensates, in part, for the toxic anti-cancer effects of the drug, leading to fewer reported incidences of CIPN than for paclitaxel.


Subject(s)
Furans/toxicity , Ketones/toxicity , Microtubules/drug effects , Microtubules/metabolism , Paclitaxel/toxicity , Peripheral Nervous System Diseases/metabolism , Peripheral Nervous System Diseases/pathology , Sciatic Nerve/drug effects , Sciatic Nerve/pathology , Acetylation/drug effects , Animals , Axons/drug effects , Axons/pathology , Female , Mice , Mice, Inbred BALB C , Microtubule-Associated Proteins/metabolism , Myelin Sheath/drug effects , Myelin Sheath/pathology , Peripheral Nervous System Diseases/chemically induced , Sciatic Neuropathy/chemically induced , Sciatic Neuropathy/metabolism , Sciatic Neuropathy/pathology , Tubulin/metabolism
12.
Can J Nurs Res ; 48(3-4): 100-109, 2016.
Article in English | MEDLINE | ID: mdl-28841075

ABSTRACT

This article overviews the second phase of a two-phase study which examined experiences of health and social exclusion among mothers experiencing homelessness in Ontario, Canada. A critical discourse analysis was employed to analyze the policy document, Realizing Our Potential: Ontario's Poverty Reduction Strategy, 2014-2019. In nursing, analysis of policy is an emerging form of scholarship, one that draws attention to the macro levels influencing health and health promotion, such as the social determinants of health, and the policies that impact them. The clear neo-liberal underpinnings, within the strategy, with a focus on productivity and labor market participation leave little room for an understanding of poverty reduction from a human rights perspective. Further, gender-neutrality rendered the poverty experienced by women, and mothers, invisible. Notably, there were a lack of deadlines, target dates, and thorough action and evaluation plans. Such absence troubles whether poverty reduction is truly a priority for the government, and society as a whole.


Subject(s)
Employment , Human Rights , Poverty , Adult , Female , Humans , Mothers , Ontario
13.
Cancer Res ; 75(18): 3696-8, 2015 Sep 15.
Article in English | MEDLINE | ID: mdl-26081810

ABSTRACT

Chemotherapy-induced peripheral neuropathy is a common, dose-limiting side effect of cancer treatment. This conference was the first of its kind to bring together a wide range of clinicians, researchers, and industry professionals to address the potential causes, preventions, and treatments for this drug toxicity. Intraepidermal nerve fiber loss, axonal degeneration, immune cell infiltration, alterations in tubulin protein expression and microtubule stability, axonal transport, and mitochondrial dysfunction were addressed as possible mechanisms. Problems with animal models of the disease were discussed, as well as the potential of patient-derived induced sensory neurons to serve as a novel in vitro model.

14.
Can J Nurs Res ; 47(3): 56-72, 2015 Sep.
Article in English, French | MEDLINE | ID: mdl-29509473

ABSTRACT

The concept of social exclusion has been proposed as an important social determinant of health. However, use of the concept in health and health promotion research is in its infancy. In nursing discourse, in particular, exploration and application of the concept of social exclusion is minimal. The purpose of this article is to explore the relevance of the concept of social exclusion in the development of nursing knowledge. Current knowledge regarding social exclusion is examined and its use in health-related research is explored. To conclude, a conceptualization of social exclusion for the development of nursing knowledge is proposed.


Il a été proposé que le concept d'exclusion sociale soit considéré comme un important déterminant social de la santé. Cependant, le recours à ce concept dans la recherche en santé et en promotion de la santé en est encore à ses balbutiements. Dans le discours des sciences infirmières en particulier, l'étude et l'application du concept d'exclusion sociale sont toujours minimes. L'objectif du présent article est d'explorer la pertinence du concept d'exclusion sociale dans le développement du savoir en sciences infirmières. Les auteures y examinent les connaissances actuelles relatives à l'exclusion sociale et leur utilisation dans la recherche liée à la santé. L'article propose en conclusion une conceptualisation de l'exclusion sociale adaptée au développement des connaissances en sciences infirmières.

15.
Can J Nurs Res ; 45(3): 80-91, 2013 Sep.
Article in English | MEDLINE | ID: mdl-24236373

ABSTRACT

Although women incarcerated by the criminal justice system encounter significant challenges to their health, there has been little research focusing on their health practices. To contribute to the research literature on the health experiences of criminalized women, the authors conducted a multi-method study as part of a program of research exploring the health promotion and health-literacy skills of women in conflict with the law. Conducting research in an incarcerated setting posed unique challenges and ethical dilemmas that problematized each phase of data collection. The authors share their experiences as health researchers conducting research in an incarcerated setting and with criminalized women. They document some of the challenges, successes, and valuable lessons learned during the research process in the hope that by sharing their knowledge with other health researchers they will support future studies with criminalized women.


Subject(s)
Health Services Research , Prisoners , Research Personnel , Confidentiality , Ethics, Research , Female , Humans
16.
J Biol Chem ; 287(35): 29765-75, 2012 Aug 24.
Article in English | MEDLINE | ID: mdl-22791716

ABSTRACT

The translation of non-stop mRNA (which lack in-frame stop codons) represents a significant quality control problem for all organisms. In eubacteria, the transfer-messenger RNA (tmRNA) system facilitates recycling of stalled ribosomes from non-stop mRNA in a process termed trans-translation or ribosome rescue. During rescue, the nascent chain is tagged with the tmRNA-encoded ssrA peptide, which promotes polypeptide degradation after release from the stalled ribosome. Escherichia coli possesses an additional ribosome rescue pathway mediated by the ArfA peptide. The E. coli arfA message contains a hairpin structure that is cleaved by RNase III to produce a non-stop transcript. Therefore, ArfA levels are controlled by tmRNA through ssrA-peptide tagging and proteolysis. Here, we examine whether ArfA homologues from other bacteria are also regulated by RNase III and tmRNA. We searched 431 arfA coding sequences for mRNA secondary structures and found that 82.8% of the transcripts contain predicted hairpins in their 3'-coding regions. The arfA hairpins from Haemophilus influenzae, Proteus mirabilis, Vibrio fischeri, and Pasteurella multocida are all cleaved by RNase III as predicted, whereas the hairpin from Neisseria gonorrhoeae functions as an intrinsic transcription terminator to generate non-stop mRNA. Each ArfA homologue is ssrA-tagged and degraded when expressed in wild-type E. coli cells, but accumulates in mutants lacking tmRNA. Together, these findings show that ArfA synthesis from non-stop mRNA is a conserved mechanism to regulate the alternative ribosome rescue pathway. This strategy ensures that ArfA homologues are only deployed when the tmRNA system is incapacitated or overwhelmed by stalled ribosomes.


Subject(s)
Codon, Terminator , Escherichia coli Proteins/biosynthesis , Escherichia coli/metabolism , Protein Biosynthesis/physiology , Proteolysis , RNA, Bacterial/metabolism , RNA-Binding Proteins/biosynthesis , Escherichia coli/genetics , Escherichia coli Proteins/genetics , Gram-Negative Bacteria/genetics , Gram-Negative Bacteria/metabolism , Nucleic Acid Conformation , RNA, Bacterial/genetics , RNA-Binding Proteins/genetics , Ribonuclease III/genetics , Ribonuclease III/metabolism , Ribosomes/genetics , Ribosomes/metabolism
17.
Acta Crystallogr Sect F Struct Biol Cryst Commun ; 67(Pt 9): 1027-31, 2011 Sep 01.
Article in English | MEDLINE | ID: mdl-21904045

ABSTRACT

Recombinant expression of proteins of interest in Escherichia coli is an important tool in the determination of protein structure. However, lack of expression and insolubility remain significant challenges to the expression and crystallization of these proteins. The SSGCID program uses a wheat germ cell-free expression system as a rescue pathway for proteins that are either not expressed or insoluble when produced in E. coli. Testing indicates that the system is a valuable tool for these protein targets. Further increases in solubility were obtained by the addition of the NVoy polymer reagent to the reaction mixture. These data indicate that this eukaryotic cell-free expression system has a high success rate and that the addition of specific reagents can increase the yield of soluble protein.


Subject(s)
Cell-Free System/chemistry , Plant Proteins/isolation & purification , Triticum/metabolism , Escherichia coli/chemistry , Escherichia coli/genetics , Escherichia coli/metabolism , Germination , Plant Proteins/genetics , Plant Proteins/metabolism , Solubility , Triticum/growth & development
18.
Can Nurse ; 105(6): 30-2, 2009 Jun.
Article in English | MEDLINE | ID: mdl-19583050

ABSTRACT

Societal abuse refers to the disadvantages that a group experience as a result of unjust social structures. People with mental illness are among the most marginalized, oppressed, devalued and stigmatized populations in our society. They experience a range of societal abuses, including barriers to health care, lack of employment, difficulty accessing and maintaining adequate housing, and discrimination. Nurses are in a unique position to address social inequity and societal abuse as advocates for health and well-being. The author addresses the impact of societal abuse and presents ways in which nurses can advocate for people with mental illness.


Subject(s)
Mental Disorders/rehabilitation , Prejudice , Stereotyping , Attitude of Health Personnel , Canada , Employment , Humans , Mental Disorders/nursing
19.
FEBS Lett ; 582(4): 497-502, 2008 Feb 20.
Article in English | MEDLINE | ID: mdl-18211810

ABSTRACT

Alterations in protein composition or dosage within chromatin may trigger changes in processes such as gene expression and DNA repair. Through transposon mutagenesis and targeted gene deletions in haploids and diploids of Saccharomyces cerevisiae, we identified mutations that affect telomeric silencing in genes encoding telomere-associated Sir4p and Yku80p and chromatin remodeling ATPases Ies2p and Rsc1p. We found that sir4/SIR4 heterozygous diploids efficiently silence the mating type locus HMR but not telomeres, and diploids heterozygous for yku80 and ies2 mutations are inefficient at DNA repair. In contrast, strains heterozygous for most chromatin remodeling ATPase mutations retain wild-type silencing and DNA repair levels. Thus, in diploids, chromatin structures required for DNA repair and telomeric silencing are sensitive to dosage changes.


Subject(s)
Chromatin/metabolism , DNA Repair , Gene Dosage , Gene Silencing , Saccharomyces cerevisiae/genetics , Transcription, Genetic
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