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1.
Lancet ; 402 Suppl 1: S14, 2023 Nov.
Article in English | MEDLINE | ID: mdl-37997053

ABSTRACT

BACKGROUND: In May 2018, the Scottish Government set a minimum unit price (MUP) of £0·50 per unit of alcohol sold in Scotland to reduce alcohol-related health harms. We synthesised evidence to establish the effects of MUP on alcohol-related health and social harms, at population level and within specific societal groups. METHODS: We did a theory-based synthesis of academic and grey research evidence about impacts of MUP in Scotland, including compliance, price, consumption, health outcomes, social outcomes, public attitudes, and the alcoholic drinks industry. We searched the Public Health Scotland's MUP evaluation portfolio and relevant grey and academic literature for studies published between Jan 1, 2018, and Jan 31, 2023. We conducted systematic searches and screening of bibliographic databases (Scopus, Public Health Database, EconLit, MEDLINE, ProQuest Public Health, Social Policy and Practice, NHS Scotland Knowledge Network Library Search, medRxiv, bioRxiv, SSRN, Idox Knowledge Exchange, Social Policy & Practice, and Google Search). Search terms were tailored to specific databases but included variants of the terms "minimum unit pricing", "alcohol", and "policy". Eligibility literature included English-language research into impacts of MUP on either the population of Scotland or a specific subpopulation. We excluded conference abstracts, literature reviews, articles that did not report research, and research based solely on data from before the introduction of MUP. FINDINGS: We included 40 reports in our analysis. On the balance of evidence, MUP improved population-level health outcomes, demonstrated most starkly by a 13·4% reduction in alcohol-attributable deaths in Scotland compared with England. There was no evidence of substantial negative effects on the alcoholic drinks industry or social harms at the population level. While population-level outcomes were predominantly positive, some qualitative evidence suggests that MUP might have exacerbated health and social harms for some individuals or groups, especially those with alcohol dependence who were financially vulnerable. INTERPRETATION: MUP in Scotland has been effective in reducing alcohol-related health harms, with little evidence of any effect on social harms. If MUP continues, policymakers should consider raising the £0·50 per unit threshold and supplementing the intervention with policies or services to address any unintended negative effects experienced by specific groups. The synthesis is persuasive due to the prospective, theory-based design of the evaluation portfolio and the quality and comprehensiveness of the evidence. FUNDING: Scottish Government.


Subject(s)
Alcoholic Beverages , Ethanol , Humans , Prospective Studies , Costs and Cost Analysis , Scotland/epidemiology , Public Policy , Alcohol Drinking/epidemiology , Alcohol Drinking/prevention & control , Commerce
2.
J Diet Suppl ; 19(5): 672-688, 2022.
Article in English | MEDLINE | ID: mdl-33949254

ABSTRACT

New Zealand blackcurrant (NZBC) extract is a rich source of anthocyanins and in order to exert physiological effects, the anthocyanin-derived metabolites need to be bioavailable in vivo. We examined the plasma uptake of selected phenolic acids following NZBC extract supplementation alongside maintaining a habitual diet (i.e. not restricting habitual polyphenol intake). Twenty healthy volunteers (nine females, age: 28 ± 7 years, height 1.73 ± 0.09 m, body mass 73 ± 11 kg) consumed a 300 mg NZBC extract capsule (CurraNZ®; anthocyanin content 105 mg) following an overnight fast. Venous blood samples were taken pre and 1, 1.5, 2, 3, 4, 5, and 6 h post-ingestion of the capsule. Reversed-phase high-performance liquid chromatography (HPLC) was used for analysis of two dihydroxybenzoic acids [i.e. vanillic acid (VA) and protocatechuic acid (PCA)] and one trihydroxybenzoic acid [i.e. gallic acid (GA)] in plasma following NZBC extract supplementation. Habitual anthocyanin intake was 168 (95%CI:68-404) mg⋅day-1 and no associations were observed between this and VA, PCA, and GA plasma uptake by the NZBC extract intake. Plasma time-concentration curves revealed that GA, and PCA were most abundant at 4, and 1.5 h post-ingestion, representing a 261% and 320% increase above baseline, respectively, with VA remaining unchanged. This is the first study to demonstrate that an NZBC extract supplement increases the plasma uptake of phenolic acids GA, and PCA even when a habitual diet is followed in the days preceding the experimental trial, although inter-individual variability is apparent.


Subject(s)
Anthocyanins , Ribes , Adult , Dietary Supplements , Female , Gallic Acid , Humans , Male , New Zealand , Plant Extracts , Ribes/chemistry , Young Adult
3.
Public Health Ethics ; 14(1): 109-116, 2021 Apr.
Article in English | MEDLINE | ID: mdl-34234843

ABSTRACT

We have been asked to consider the feasibility of piloting a Citizens' Basic Income (CBI): a basic, unconditional, universal, individual, regular payment that would replace aspects of social security and be introduced alongside changes to taxes. Piloting and evaluating a CBI as a Cluster Randomized Control Trial (RCT) raises the question of whether intervention and comparison groups would be in equipoise, and thus whether randomization would be ethical. We believe that most researchers would accept that additional income, or reduced conditions on receiving income would be likely to improve health, especially at lower income levels. However, there are genuine uncertainties about the impacts on other outcomes, and CBI as a mechanism of providing income. There is also less consensus amongst civil servants and politicians about the impacts on health, and substantial disagreement about whether these would outweigh other impacts. We believe that an RCT is ethical because of these uncertainties. We also argue that the principle of equipoise should apply to randomized and non-randomized trials; that randomization is a fairer means of allocating to intervention and comparison groups; and that there is an ethical case for experimentation to generate higher-quality evidence for policymaking that may otherwise do harm.

4.
BMJ Open Sport Exerc Med ; 7(1): e000982, 2021.
Article in English | MEDLINE | ID: mdl-33489310

ABSTRACT

OBJECTIVE: Altitude-related and exercise-related elevations in blood pressure (BP) increase the likelihood of developing pulmonary hypertension and high-altitude illness during high-altitude sojourn. This study examined the antihypertensive effect and potential exercise benefit of the angiotensin II receptor antagonist losartan when taken at altitude. METHODS: Twenty participants, paired for age and ACE genotype status, completed a double-blinded, randomised study, where participants took either losartan (100 mg/day) or placebo for 21 days prior to arrival at 5035 m (Whymper Hut, Mt Chimborazo, Ecuador). Participants completed a maximal exercise test on a supine cycle ergometer at sea level (4 weeks prior) and within 48 hours of arrival to 5035 m (10-day ascent). Power output, beat-to-beat BP, oxygen saturation (SpO2) and heart rate (HR) were recorded during exercise, with resting BP collected from daily medicals during ascent. Before and immediately following exercise at 5035 m, extravascular lung water prevalence was assessed with ultrasound (quantified via B-line count). RESULTS: At altitude, peak power was reduced relative to sea level (p<0.01) in both groups (losartan vs placebo: down 100±29 vs 91±28 W, p=0.55), while SpO2 (70±6 vs 70±5%, p=0.96) and HR (146±21 vs 149±24 bpm, p=0.78) were similar between groups at peak power, as was the increase in systolic BP from rest to peak power (up 80±37 vs 69±33 mm Hg, p=0.56). Exercise increased B-line count (p<0.05), but not differently between groups (up 5±5 vs 8±10, p=0.44). CONCLUSION: Losartan had no observable effect on resting or exercising BP, exercise-induced symptomology of pulmonary hypertension or performance at 5035 m.

5.
Int J Sport Nutr Exerc Metab ; 30(4): 287-294, 2020 07 01.
Article in English | MEDLINE | ID: mdl-32470924

ABSTRACT

New Zealand blackcurrant (NZBC) contains anthocyanins, known to moderate blood flow and display anti-inflammatory properties that may improve recovery from exercise-induced muscle damage. The authors examined whether NZBC extract supplementation enhances recovery from exercise-induced muscle damage after a half-marathon race. Following a randomized, double-blind, independent groups design, 20 (eight women) recreational runners (age 30 ± 6 years, height 1.73 ± 0.74 m, body mass 68.5 ± 7.8 kg, half-marathon finishing time 1:56:33 ± 0:18:08 hr:min:s) ingested either two 300-mg/day capsules of NZBC extract (CurraNZ™) or a visually matched placebo, for 7 days prior to and 2 days following a half-marathon. Countermovement jump performance variables, urine interleukin-6, and perceived muscle soreness and fatigue were measured pre, post, and at 24 and 48 hr after the half-marathon and analyzed using a mixed linear model with statistical significance set a priori at p < .05. The countermovement jump performance variables were reduced immediately post-half-marathon (p < .05), with all returning to pre-half-marathon levels by 48 hr, except the concentric and eccentric peak force and eccentric duration, with no difference in response between groups (p > .05). Urine interleukin-6 increased 48-hr post-half-marathon in the NZBC group only (p < .01) and remained unchanged compared with pre-half-marathon levels in the placebo group (p > .05). Perceived muscle soreness and fatigue increased immediately post-half-marathon (p < .01) and returned to pre-half-marathon levels by 48 hr, with no difference between groups (p > .05). Supplementation with NZBC extract had no effect on the recovery of countermovement jump variables and perceptions of muscle soreness or fatigue following a half-marathon in recreational runners.


Subject(s)
Marathon Running , Muscle Fatigue/drug effects , Muscle, Skeletal/physiology , Myalgia/drug therapy , Plant Extracts/administration & dosage , Ribes/chemistry , Adult , Dietary Supplements , Double-Blind Method , Female , Humans , Male , New Zealand , Sports Nutritional Physiological Phenomena , Young Adult
6.
BMJ Open Sport Exerc Med ; 6(1): e000662, 2020.
Article in English | MEDLINE | ID: mdl-32341794

ABSTRACT

INTRODUCTION: Proteinuria increases at altitude and with exercise, potentially as a result of hypoxia. Using urinary alpha-1 acid glycoprotein (α1-AGP) levels as a sensitive marker of proteinuria, we examined the impact of relative hypoxia due to high altitude and blood pressure-lowering medication on post-exercise proteinuria. METHODS: Twenty individuals were pair-matched for sex, age and ACE genotype. They completed maximal exercise tests once at sea level and twice at altitude (5035 m). Losartan (100 mg/day; angiotensin-receptor blocker) and placebo were randomly assigned within each pair 21 days before ascent. The first altitude exercise test was completed within 24-48 hours of arrival (each pair within ~1 hour). Acetazolamide (125 mg two times per day) was administrated immediately after this test for 48 hours until the second altitude exercise test. RESULTS: With placebo, post-exercise α1-AGP levels were similar at sea level and altitude. Odds ratio (OR) for increased resting α1-AGP at altitude versus sea level was greater without losartan (2.16 times greater). At altitude, OR for reduced post-exercise α1-AGP (58% lower) was higher with losartan than placebo (2.25 times greater, p=0.059) despite similar pulse oximetry (SpO2) (p=0.95) between groups. Acetazolamide reduced post-exercise proteinuria by approximately threefold (9.3±9.7 vs 3.6±6.0 µg/min; p=0.025) although changes were not correlated (r=-0.10) with significant improvements in SpO2 (69.1%±4.5% vs 75.8%±3.8%; p=0.001). DISCUSSION: Profound systemic hypoxia imposed by altitude does not result in greater post-exercise proteinuria than sea level. Losartan and acetazolamide may attenuate post-exercise proteinuria, however further research is warranted.

7.
Article in English | MEDLINE | ID: mdl-31349618

ABSTRACT

The Scottish Government launched a tobacco control strategy in 2013 with the ambition of making Scotland tobacco smoke-free by 2034. However, 17% of the adult population in Scotland smoke cigarettes. This study aimed to provide insight into why policies are successful or not and provide suggestions for future policy actions. Individual interviews with ten tobacco control experts were conducted and the results were analyzed using thematic analysis. Key successes included strong political leadership, mass media campaigns, legislation to address availability and marketing of cigarettes and tobacco products, and legislation to reduce second-hand smoke exposure. Challenges included implementing policy actions, monitoring and evaluation of tobacco control actions, addressing health inequalities in smoking prevalence, and external factors that influenced the success of policy actions. Key suggestions put forward for future policy actions included addressing the price and availability of tobacco products, maintaining strong political leadership on tobacco control, building on the success of the 'Take it Right Outside' mass media campaign with further mass media campaigns to tackle other aspects of tobacco control, and developing and testing methods of addressing inequalities in cigarette smoking prevalence. The findings of this study can inform future tobacco control policy in Scotland and have relevance for tobacco control policies in other countries.


Subject(s)
Attitude to Health , Marketing/legislation & jurisprudence , Public Health/legislation & jurisprudence , Smoking Prevention/legislation & jurisprudence , Tobacco Smoke Pollution/legislation & jurisprudence , Tobacco Smoking/psychology , Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Qualitative Research , Scotland
8.
Curr Protoc Cell Biol ; 74: 17.20.1-17.20.10, 2017 Mar 03.
Article in English | MEDLINE | ID: mdl-28256719

ABSTRACT

Techniques for studying RNA-protein interactions have lagged behind those for DNA-protein interactions as a consequence of the complexities associated with working with RNA. This unit describes a method for the adaptation of the In Situ Hybridization-Proximity Ligation Assay (ISH-PLA) to the study of RNA regulation (rISH-PLA). The rISH-PLA assay allows the identification of a given RNA-protein complex at subcellular and single-cell resolution, thus avoiding the lack of spatial resolution and sensitivity associated with assaying heterogeneous cell populations from which conventional RNA-protein interaction detection techniques suffer. This technique will be particularly usefully for studying the activity of RNA binding proteins (RBPs) in complex mixtures of cells, for example tissue sections or whole embryos. © 2017 by John Wiley & Sons, Inc.


Subject(s)
In Situ Hybridization/methods , Protein Interaction Mapping/methods , RNA-Binding Proteins/analysis , RNA/analysis , Animals , Oocytes/metabolism , RNA/chemistry , Xenopus
9.
Gene ; 599: 78-86, 2017 Jan 30.
Article in English | MEDLINE | ID: mdl-27836664

ABSTRACT

Vesicle shuttling is critical for many cellular and organismal processes, including embryonic development. GDI proteins contribute to vesicle shuttling by regulating the activity of Rab GTPases, controlling their cycling between the inactive cytosol and active membrane bound states. While identifying genes controlled by A-form DNA sequences we discovered a previously unknown member of the GDI family, GDI3. The GDI3 gene is found only in amphibians and fish and is developmentally expressed in Xenopus from neurula stages onwards in the neural plate, and subsequently in both dorsal and anterior structures. Depletion or over-expression of the GDI3 protein in Xenopus embryos gives rise to very similar phenotypes, suggesting that strict control of GDI3 protein levels is required for correct embryonic development. Our analysis suggests the evolutionary origins of GDI3 and that it is functionally distinct from GDI1. Predicted structural analysis of GDI3 suggests that the key difference between GDI1 and GDI3 lies in their lipid binding pockets.


Subject(s)
Guanine Nucleotide Dissociation Inhibitors/metabolism , Neurogenesis/physiology , Xenopus Proteins/metabolism , Xenopus/embryology , Xenopus/metabolism , rab GTP-Binding Proteins/metabolism , Animals , Base Sequence , Cloning, Molecular , DNA/genetics , Gene Expression Regulation, Developmental , Guanine Nucleotide Dissociation Inhibitors/chemistry , Guanine Nucleotide Dissociation Inhibitors/genetics , Models, Molecular , Neurogenesis/genetics , Phylogeny , Xenopus/genetics , Xenopus Proteins/chemistry , Xenopus Proteins/genetics , rab GTP-Binding Proteins/chemistry , rab GTP-Binding Proteins/genetics
10.
PLoS One ; 11(1): e0147967, 2016.
Article in English | MEDLINE | ID: mdl-26824753

ABSTRACT

Techniques for studying RNA-protein interactions have lagged behind those for DNA-protein complexes as a consequence of the complexities associated with working with RNA. Here we present a method for the modification of the existing In Situ Hybridisation-Proximity Ligation Assay (ISH-PLA) protocol to adapt it to the study of RNA regulation (rISH-PLA). As proof of principle we used the well-characterised interaction of the Xenopus laevis Staufen RNA binding protein with Vg1 mRNA, the complex of which co-localises to the vegetal pole of Xenopus oocytes. The applicability of both the Stau1 antibody and the Locked Nucleic Acid probe (LNA) recognising Vg1 mRNA were independently validated by whole-mount Immunohistochemistry and whole-mount in situ hybridisation assays respectively prior to combining them in the rISH-PLA assay. The rISH-PLA assay allows the identification of a given RNA-protein complex at subcellular and single cell resolution, thus avoiding the lack of spatial resolution and sensitivity associated with assaying heterogenous cell populations from which conventional RNA-protein interaction detection techniques suffer. This technique will be particularly usefully for studying the activity of RNA binding proteins (RBPs) in complex mixtures of cells, for example tissue sections or whole embryos.


Subject(s)
Biological Assay , Immunohistochemistry/methods , Oocytes/metabolism , RNA, Messenger/metabolism , RNA-Binding Proteins/metabolism , Single-Cell Analysis/methods , Xenopus Proteins/metabolism , Animals , Antibodies/chemistry , Binding Sites , Biotin/chemistry , Gene Expression , In Situ Hybridization , Mice , Oligonucleotides/chemistry , Oocytes/cytology , Protein Binding , RNA, Messenger/genetics , RNA-Binding Proteins/genetics , Rabbits , Transforming Growth Factor beta/genetics , Transforming Growth Factor beta/metabolism , Xenopus Proteins/genetics , Xenopus laevis
11.
Curr Genomics ; 14(4): 256-67, 2013 Jun.
Article in English | MEDLINE | ID: mdl-24294106

ABSTRACT

Skeletal muscle is a post-mitotic tissue maintained by repair and regeneration through a population of stem cell-like satellite cells. Following muscle injury, satellite cell proliferation is mediated by local signals ensuring sufficient progeny for tissue repair. Age-related changes in satellite cells as well as to the local and systemic environment potentially impact on the capacity of satellite cells to generate sufficient progeny in an ageing organism resulting in diminished regeneration. 'Rejuvenation' of satellite cell progeny and regenerative capacity by environmental stimuli effectors suggest that a subset of age-dependent satellite cell changes may be reversible. Epigenetic regulation of satellite stem cells that include DNA methylation and histone modifications which regulate gene expression are potential mechanisms for such reversible changes and have been shown to control organismal longevity. The area of health and ageing that is likely to benefit soonest from advances in the biology of adult stem cells is the emerging field of regenerative medicine. Further studies are needed to elucidate the mechanisms by which epigenetic modifications regulate satellite stem cell function and will require an increased understanding of stem-cell biology, the environment of the aged tissue and the interaction between the two.

12.
Suicide Life Threat Behav ; 41(1): 98-109, 2011 Feb.
Article in English | MEDLINE | ID: mdl-21309828

ABSTRACT

This article presents a sociologically informed critique of a range of academic literatures relating to self-injury. It is noted how a lack of consensus on definitional issues, together with the inaccurate portrayal of the "typical self-injurer" in the clinical literature, has impeded the development of a sound understanding of self-injury. Some of the more problematic explanations for self-injury are explored. The individualistic focus of existing research is found to be inadequate, since it fails to account for the social context in which self-injury occurs. Social scientific approaches critically examine psychiatric and psychological constructions of self-injury, explore wider social and cultural meanings of the behavior, and examine its distribution across different social groups. The inclusion of social scientific perspectives into current debates will greatly improve understanding of self-injury.


Subject(s)
Self-Injurious Behavior/psychology , Sociology , Adolescent , Adult , Age Factors , Female , Humans , Male , Self Mutilation/classification , Self Mutilation/psychology , Self-Injurious Behavior/classification , Sex Factors , Sexuality/psychology , Social Class , Suicide/classification , Suicide/psychology , Terminology as Topic , Young Adult
13.
Biochim Biophys Acta ; 1799(9): 642-52, 2010 Sep.
Article in English | MEDLINE | ID: mdl-20800709

ABSTRACT

Antibodies to the six chicken histone H1 subtypes and the variant histone H5 have been used in immunoprecipitations of crosslinked chromatin fragments (xChIPs) to map linker histones across the ß-globin locus and the widely expressed glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and carbonic anhydrase (CA) genes in three cell types: 15-day embryo chicken erythrocytes, 15-day embryo chicken brain and the early erythroid cell line HD24. In erythrocytes, where the ß-adult and ß-hatching genes are active, the H1.01, H1.11L and H1.11R subtypes are substantially depleted throughout the ß-globin locus and the neighboring heterochromatin, in contrast to the other four subtypes, in particular the more abundant H5. Active genes therefore carry high levels of some but not all linker histone subtypes. The situation is similar in HD24 cells, except that substantial depletions are found at the promoters of the adult ß(A) and embryonic ß(ρ) and ß(ε) genes, despite these genes not yet being active in HD24 cells. The distributions in the brain tissue are characterised by the absence of H1.02, H1.03 and H5 from the hypersensitive site HS3 and from the ß-adult 3' enhancer for the H1.11L and H1.11R subtypes. The data show that although linker histone subtypes play distinct cell-type specific roles in gene regulation, their widespread distribution indicates they are not intrinsically inhibitory to basic chromatin transactions.


Subject(s)
Histones/genetics , Histones/metabolism , Repressor Proteins/metabolism , Animals , Chick Embryo , Chromatin Immunoprecipitation , Chromosome Mapping/methods , Cross-Linking Reagents/pharmacology , Gene Expression Regulation , Genetic Loci , Humans , Protein Binding , Regulatory Sequences, Nucleic Acid/physiology , Repressor Proteins/classification , Repressor Proteins/immunology , beta-Globins/genetics , beta-Globins/metabolism
14.
J Mol Biol ; 386(2): 290-9, 2009 Feb 20.
Article in English | MEDLINE | ID: mdl-19136010

ABSTRACT

Quantitative measurements of local chromatin accessibility to DNase I in 15-day chicken embryo erythrocyte nuclei have been performed using a range of nuclease concentrations and real-time TaqMan PCR to monitor the loss of short ( approximately 80 bp) amplicons. At the beta-globin locus, well-established DNase I hypersensitive sites stand out against a background in which actively transcribed gene sequences (e.g., beta-adult and beta-hatching) are no more sensitive than the nearby constitutive heterochromatin that has previously been shown to form the 30-nm fibre structure. Similar observations were made at the lysozyme locus containing the active Gas41 gene and also at the GAPDH locus. We conclude that active genes are not continuously held in an open 'beads-on-a-string' configuration, but adopt a 30-nm-type structure most of the time. This implies that the compact nucleosomal supercoil re-forms in the wake of the polymerase complex.


Subject(s)
Chromatin/chemistry , Animals , Chick Embryo , DNA/metabolism , Deoxyribonuclease I/metabolism , Erythrocytes/chemistry , Polymerase Chain Reaction/methods , Transcription, Genetic
15.
Nucleic Acids Res ; 34(14): 4025-35, 2006.
Article in English | MEDLINE | ID: mdl-16914441

ABSTRACT

Native chromatin IP assays were used to define changes in core histone acetylation at the lysozyme locus during developmental maturation of chicken macrophages and stimulation to high-level expression by lipo-polysaccharide. In pluripotent precursors the lysozyme gene (Lys) is inactive and there is no acetylation of core histones at the gene, its promoter or at the upstream cis-control elements. In myeloblasts, where there is a very low level of Lys expression, H4 acetylation appears at the cis-control elements but not at the Lys gene or its promoter: neither H3 nor H2B become significantly acetylated in myeloblasts. In mature macrophages, Lys expression increases 5-fold: H4, H2B and H2A.Z are all acetylated at the cis-control elements but H3 remains unacetylated except at the -2.4 S silencer. Stimulation with LPS increases Lys expression a further 10-fold: this is accompanied by a rise in H3 acetylation throughout the cis-control elements; H4 and H2B acetylation remain substantial but acetylation at the Lys gene and its promoter remains low. Acetylation is thus concentrated at the cis-control elements, not at the Lys gene or its immediate promoter. H4 acetylation precedes H3 acetylation during development and H3 acetylation is most directly linked to high-level Lys expression.


Subject(s)
Chickens/genetics , Enhancer Elements, Genetic , Histones/metabolism , Macrophages/metabolism , Muramidase/genetics , Acetylation , Animals , Antibodies , Cell Line , Chickens/growth & development , Chickens/metabolism , Chromatin Immunoprecipitation , Gene Expression Regulation, Developmental , Granulocyte Precursor Cells/metabolism , Histones/immunology , Muramidase/metabolism , Pluripotent Stem Cells/metabolism , RNA, Messenger/metabolism , Transcriptional Activation
17.
Nucleic Acids Res ; 33(17): 5633-9, 2005.
Article in English | MEDLINE | ID: mdl-16204459

ABSTRACT

The replacement histone H2A.Z is variously reported as being linked to gene expression and preventing the spread of heterochromatin in yeast, or concentrated at heterochromatin in mammals. To resolve this apparent dichotomy, affinity-purified antibodies against the N-terminal region of H2A.Z, in both a triacetylated and non-acetylated state, are used in native chromatin immmuno-precipitation experiments with mononucleosomes from three chicken cell types. The hyperacetylated species concentrates at the 5' end of active genes, both tissue specific and housekeeping but is absent from inactive genes, while the unacetylated form is absent from both active and inactive genes. A concentration of H2A.Z is also found at insulators under circumstances implying a link to barrier activity but not to enhancer blocking. Although acetylated H2A.Z is widespread throughout the interphase genome, at mitosis its acetylation is erased, the unmodified form remaining. Thus, although H2A.Z may operate as an epigenetic marker for active genes, its N-terminal acetylation does not.


Subject(s)
Histones/analysis , Transcription, Genetic , Acetylation , Animals , Antibodies/immunology , Cells, Cultured , Chick Embryo , Chickens/genetics , Histones/immunology , Histones/metabolism
18.
Biochim Biophys Acta ; 1729(1): 57-63, 2005 May 25.
Article in English | MEDLINE | ID: mdl-15823506

ABSTRACT

Formaldehyde-crosslinked and sonicated chromatin fragments were obtained from 15-day chicken embryo erythrocytes and purified on caesium chloride gradients. Polyclonal antibodies raised against chicken HMGB1 were used to immuno-precipitate fragments carrying HMGB1 in two protocols: (1) affinity purified antibodies covalently coupled to agarose beads and (2) diluted antiserum. The DNA of the antibody-bound chromatin was quantified and its sequence content assessed by quantitative real-time PCR to give values of the absolute enrichments generated. Amplicons were monitored within the active beta-globin locus, in the adjacent heterochromatin, in the lysozyme locus (containing an active housekeeping gene and the inactive lysozyme gene) and at the promoter of the inactive ovalbumin gene. For all amplicons the Bound/Input ratio was close to unity, implying no preferential location of HMGB1 on the chromatin. This initially unexpected result can now be understood in the light of the exceptional mobility of HMGB1 revealed by FLIP experiments showing that only 1-2 s are needed for HMGB1 to cross the nucleus: crosslinking times of 1 min were used in the present experiments.


Subject(s)
Chromatin Assembly and Disassembly/physiology , Erythrocytes/metabolism , HMGB1 Protein/metabolism , Heterochromatin/metabolism , Nuclear Matrix/metabolism , Active Transport, Cell Nucleus/physiology , Animals , Chick Embryo , Chromatin Immunoprecipitation , Promoter Regions, Genetic/genetics , Promoter Regions, Genetic/physiology , Protein Binding , Quantitative Trait Loci/physiology
19.
J Biol Chem ; 280(18): 17732-6, 2005 May 06.
Article in English | MEDLINE | ID: mdl-15760899

ABSTRACT

Methylation of lysine 4 of histone H3 (K4/H3) is linked to transcriptional activity, whereas methylation of K9/H3 is tightly associated with gene inactivity. These are well characterized sites of methylation within histones, but there are numerous other, less characterized, sites of modification. In Saccharomyces cerevisiae, methylation of K36/H3 has been linked to active genes, but little is known about this methylation in higher eukaryotes. Here we analyzed for the first time the levels and spatial distribution of di- and tri-methyl (di- and tri-Me) K36/H3 in metazoan genes. We analyzed chicken genes that are developmentally regulated, constitutively active, or inactive. We found that active genes contain high levels of these modifications compared with inactive genes. Furthermore, in actively transcribed regions the levels of di- and tri-Me K36/H3 peak toward the 3' end of the gene. This is in striking contrast to the distributions of di- and tri-Me K4/H3, which peak early in actively transcribed regions. Thus, di/tri-Me K4/H3 and di/tri-Me K36/H3 are both useful markers of active genes, but their genic distribution indicates differing roles. Our data suggest that the unique spatial distribution of di- and tri-Me K36/H3 plays a role in transcriptional termination and/or early RNA processing.


Subject(s)
Gene Expression Regulation , Histones/genetics , Histones/metabolism , Lysine/analogs & derivatives , Animals , Chickens , DNA Methylation , Lysine/genetics , Lysine/metabolism
20.
Methods Mol Biol ; 287: 21-44, 2004.
Article in English | MEDLINE | ID: mdl-15273401

ABSTRACT

Chromatin immunoprecipitation (ChIP) is a technique widely used for determining the genomic location of modified histones and other chromatin-associated factors. Here we describe the methodology we have used in our laboratory for the immunoprecipitation of chromatin isolated from cells in the absence of crosslinking. Chromatin released from nuclei by micrococcal nuclease digestion is centrifuged through sucrose gradients to allow selection of mono- or dinucleosomes. This allows a protein or modification at a particular gene or locus to be mapped at higher resolution than in a crosslinked ChIP experiment. Two methods for the immunoprecipitation of chromatin are described: a large-scale fractionation by which it is possible to visualize the proteins of the immunoprecipitate by polyacrylamide gel electrophoresis, PAGE and a small-scale method that is more appropriate when the quantity of chromatin is limited. The sequence content of DNA extracted from the immunoprecipitated chromatin is analyzed by hybridization of Southern or slot blots, or by quantitative polymerase chain reaction. Enrichment of particular sequences in the immunoprecipitated fraction reveals the presence and extent of the modification at this location.


Subject(s)
Chromatin/chemistry , Chromatin/isolation & purification , Precipitin Tests/methods , Animals , Antibodies/isolation & purification , Cells, Cultured , Chickens/genetics , Chromatin/immunology , DNA/analysis , Erythrocytes/chemistry , Erythrocytes/physiology , Histones/chemistry , Humans , K562 Cells , Polymerase Chain Reaction/methods
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