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1.
J Am Heart Assoc ; 12(4): e024303, 2023 02 21.
Article in English | MEDLINE | ID: mdl-36789992

ABSTRACT

Background Proper function of endothelial cells is critical for vascular integrity and organismal survival. Studies over the past 2 decades have identified 2 members of the KLF (Krüppel-like factor) family of proteins, KLF2 and KLF4, as nodal regulators of endothelial function. Strikingly, inducible postnatal deletion of both KLF2 and KLF4 resulted in widespread vascular leak, coagulopathy, and rapid death. Importantly, while transcriptomic studies revealed profound alterations in gene expression, the molecular mechanisms underlying these changes remain poorly understood. Here, we seek to determine mechanisms of KLF2 and KLF4 transcriptional control in multiple vascular beds to further understand their roles as critical endothelial regulators. Methods and Results We integrate chromatin occupancy and transcription studies from multiple transgenic mouse models to demonstrate that KLF2 and KLF4 have overlapping yet distinct binding patterns and transcriptional targets in heart and lung endothelium. Mechanistically, KLFs use open chromatin regions in promoters and enhancers and bind in context-specific patterns that govern transcription in microvasculature. Importantly, this occurs during homeostasis in vivo without additional exogenous stimuli. Conclusions Together, this work provides mechanistic insight behind the well-described transcriptional and functional heterogeneity seen in vascular populations, while also establishing tools into exploring microvascular endothelial dynamics in vivo.


Subject(s)
Endothelium , Kruppel-Like Factor 4 , Kruppel-Like Transcription Factors , Animals , Mice , Chromatin/metabolism , Endothelial Cells/metabolism , Endothelium/metabolism , Gene Expression , Kruppel-Like Factor 4/genetics , Kruppel-Like Factor 4/metabolism , Kruppel-Like Transcription Factors/genetics , Kruppel-Like Transcription Factors/metabolism
2.
iScience ; 25(11): 105292, 2022 Nov 18.
Article in English | MEDLINE | ID: mdl-36304102

ABSTRACT

Brown adipose tissue (BAT) is a specialized metabolic organ responsible for non-shivering thermogenesis. Recently, its activity has been shown to be critical in systemic metabolic health through its utilization and consumption of macronutrients. In the face of energetically demanding states, metabolic flexibility and systemic coordination of nutrient partitioning is requisite for health and survival. In this study, we elucidate BAT's differential transcriptional adaptations in response to multiple nutrient challenges and demonstrate its context-dependent prioritization of lipid, glucose, and amino acid metabolism. We show that the transcription factor Krüppel-like factor 15 (KLF15) plays a critical role in BAT metabolic flexibility. BAT-specific loss of KLF15 results in widespread changes in circulating metabolites and severely compromised thermogenesis in response to high energy demands, indicative of impaired nutrient utilization and metabolic flexibility. Together, our data demonstrate KLF15 in BAT plays an indispensable role in partitioning resources to maintain homeostasis and ensure survival.

3.
Sci Transl Med ; 14(660): eabj7465, 2022 08 31.
Article in English | MEDLINE | ID: mdl-36044595

ABSTRACT

Arterial and venous thrombosis constitutes a major source of morbidity and mortality worldwide. Long considered as distinct entities, accumulating evidence indicates that arterial and venous thrombosis can occur in the same populations, suggesting that common mechanisms are likely operative. Although hyperactivation of the immune system is a common forerunner to the genesis of thrombotic events in both vascular systems, the key molecular control points remain poorly understood. Consequently, antithrombotic therapies targeting the immune system for therapeutics gain are lacking. Here, we show that neutrophils are key effectors of both arterial and venous thrombosis and can be targeted through immunoregulatory nanoparticles. Using antiphospholipid antibody syndrome (APS) as a model for arterial and venous thrombosis, we identified the transcription factor Krüppel-like factor 2 (KLF2) as a key regulator of neutrophil activation. Upon activation through genetic loss of KLF2 or administration of antiphospholipid antibodies, neutrophils clustered P-selectin glycoprotein ligand 1 (PSGL-1) by cortical actin remodeling, thereby increasing adhesion potential at sites of thrombosis. Targeting clustered PSGL-1 using nanoparticles attenuated neutrophil-mediated thrombosis in APS and KLF2 knockout models, illustrating the importance and feasibility of targeting activated neutrophils to prevent pathological thrombosis. Together, our results demonstrate a role for activated neutrophils in both arterial and venous thrombosis and identify key molecular events that serve as potential targets for therapeutics against diverse causes of immunothrombosis.


Subject(s)
Antiphospholipid Syndrome , Thrombosis , Venous Thrombosis , Antibodies, Antiphospholipid , Humans , Neutrophils/metabolism , Thrombosis/etiology
4.
Front Genet ; 13: 870700, 2022.
Article in English | MEDLINE | ID: mdl-35646068

ABSTRACT

A small non-histone protein of budding yeast, Nhp6 has been reported to specifically influence the transcription of a yeast gene, SNR6. The gene is essential, transcribed by the enzyme RNA polymerase III, and codes for the U6snRNA required for mRNA splicing. A translationally positioned nucleosome on the gene body enables the assembly factor TFIIIC binding by juxtaposing its otherwise widely separated binding sites, boxes A and B. We found histone depletion results in the loss of U6 snRNA production. Changing the rotational phase of the boxes and the linear distance between them with deletions in 5 bp steps displayed a helical periodicity in transcription, which gradually reduced with incremental deletions up to 40 bp but increased on further deletions enclosing the pseudoA boxes. Nhp6 influences the transcription in a dose-dependent manner, which is modulated by its previously reported co-operator, an upstream stretch of seven T residues centered between the TATA box and transcription start site. Nhp6 occupancy on the gene in vivo goes up at least 2-fold under the repression conditions. Nhp6 absence, T7 disruption, or shorter A-B box distance all cause the downstream initiation of transcription. The right +1 site is selected with the correct placement of TFIIIC before the transcription initiation factor TFIIIB. Thus, the T7 sequence and Nhp6 help the assembly and placement of the transcription complex at the right position. Apart from the chromatin remodelers, the relative rotational orientation of the promoter elements in nucleosomal DNA, and Nhp6 regulate the transcription of the SNR6 gene with precision.

5.
J Biol Chem ; 298(6): 101926, 2022 06.
Article in English | MEDLINE | ID: mdl-35413288

ABSTRACT

Skeletal muscle dynamically regulates systemic nutrient homeostasis through transcriptional adaptations to physiological cues. In response to changes in the metabolic environment (e.g., alterations in circulating glucose or lipid levels), networks of transcription factors and coregulators are recruited to specific genomic loci to fine-tune homeostatic gene regulation. Elucidating these mechanisms is of particular interest as these gene regulatory pathways can serve as potential targets to treat metabolic disease. The zinc-finger transcription factor Krüppel-like factor 15 (KLF15) is a critical regulator of metabolic homeostasis; however, its genome-wide distribution in skeletal muscle has not been previously identified. Here, we characterize the KLF15 cistrome in vivo in skeletal muscle and find that the majority of KLF15 binding is localized to distal intergenic regions and associated with genes related to circadian rhythmicity and lipid metabolism. We also identify critical interdependence between KLF15 and the nuclear receptor PPARδ in the regulation of lipid metabolic gene programs. We further demonstrate that KLF15 and PPARδ colocalize genome-wide, physically interact, and are dependent on one another to exert their transcriptional effects on target genes. These findings reveal that skeletal muscle KLF15 plays a critical role in metabolic adaptation through its direct actions on target genes and interactions with other nodal transcription factors such as PPARδ.


Subject(s)
Kruppel-Like Transcription Factors , Lipid Metabolism , Muscle, Skeletal , PPAR delta , Animals , Kruppel-Like Transcription Factors/genetics , Kruppel-Like Transcription Factors/metabolism , Lipid Metabolism/genetics , Mice , Muscle, Skeletal/metabolism , PPAR delta/genetics , PPAR delta/metabolism
6.
J Clin Invest ; 132(3)2022 02 01.
Article in English | MEDLINE | ID: mdl-34793333

ABSTRACT

It is widely recognized that inflammation plays a critical role in cardiac hypertrophy and heart failure. However, clinical trials targeting cytokines have shown equivocal effects, indicating the need for a deeper understanding of the precise role of inflammation and inflammatory cells in heart failure. Leukocytes from human subjects and a rodent model of heart failure were characterized by a marked reduction in expression of Klf2 mRNA. Using a mouse model of angiotensin II-induced nonischemic cardiac dysfunction, we showed that neutrophils played an essential role in the pathogenesis and progression of heart failure. Mechanistically, chronic angiotensin II infusion activated a neutrophil KLF2/NETosis pathway that triggered sporadic thrombosis in small myocardial vessels, leading to myocardial hypoxia, cell death, and hypertrophy. Conversely, targeting neutrophils, neutrophil extracellular traps (NETs), or thrombosis ameliorated these pathological changes and preserved cardiac dysfunction. KLF2 regulated neutrophil activation in response to angiotensin II at the molecular level, partly through crosstalk with HIF1 signaling. Taken together, our data implicate neutrophil-mediated immunothrombotic dysregulation as a critical pathogenic mechanism leading to cardiac hypertrophy and heart failure. This neutrophil KLF2-NETosis-thrombosis mechanism underlying chronic heart failure can be exploited for therapeutic gain by therapies targeting neutrophils, NETosis, or thrombosis.


Subject(s)
Cardiomegaly/metabolism , Heart Failure/metabolism , Kruppel-Like Transcription Factors/metabolism , Neutrophil Activation , Neutrophils/metabolism , Thrombosis/metabolism , Animals , Disease Models, Animal , Humans , Mice
7.
J Clin Invest ; 131(4)2021 02 15.
Article in English | MEDLINE | ID: mdl-33586679

ABSTRACT

Skeletal muscle is a major determinant of systemic metabolic homeostasis that plays a critical role in glucose metabolism and insulin sensitivity. By contrast, despite being a major user of fatty acids, and evidence that muscular disorders can lead to abnormal lipid deposition (e.g., nonalcoholic fatty liver disease in myopathies), our understanding of skeletal muscle regulation of systemic lipid homeostasis is not well understood. Here we show that skeletal muscle Krüppel-like factor 15 (KLF15) coordinates pathways central to systemic lipid homeostasis under basal conditions and in response to nutrient overload. Mice with skeletal muscle-specific KLF15 deletion demonstrated (a) reduced expression of key targets involved in lipid uptake, mitochondrial transport, and utilization, (b) elevated circulating lipids, (c) insulin resistance/glucose intolerance, and (d) increased lipid deposition in white adipose tissue and liver. Strikingly, a diet rich in short-chain fatty acids bypassed these defects in lipid flux and ameliorated aspects of metabolic dysregulation. Together, these findings establish skeletal muscle control of lipid flux as critical to systemic lipid homeostasis and metabolic health.


Subject(s)
Homeostasis , Kruppel-Like Transcription Factors/metabolism , Lipid Metabolism , Mitochondria, Muscle/metabolism , Muscle, Skeletal/metabolism , Animals , Kruppel-Like Transcription Factors/genetics , Mice , Mice, Knockout , Mitochondria, Muscle/genetics
8.
iScience ; 23(11): 101728, 2020 Nov 20.
Article in English | MEDLINE | ID: mdl-33241196

ABSTRACT

Particulate matter ≤2.5µm (PM2.5) air pollution is a leading environmental risk factor contributing disproportionately to the global burden of non-communicable disease. We compared impact of chronic exposure to PM2.5 alone, or with light at night exposure (LL) on metabolism. PM2.5 induced peripheral insulin resistance, circadian rhythm (CR) dysfunction, and metabolic and brown adipose tissue (BAT) dysfunction, akin to LL (with no additive interaction between PM2.5 and LL). Transcriptomic analysis of liver and BAT revealed widespread but unique alterations in CR genes, with evidence for differentially accessible promoters and enhancers of CR genes in response to PM2.5 by ATAC-seq. The histone deacetylases 2, 3, and 4 were downregulated with PM2.5 exposure, with increased promoter occupancy by the histone acetyltransferase p300 as evidenced by ChIP-seq. These findings suggest a previously unrecognized role of PM2.5 in promoting CR disruption and metabolic dysfunction through epigenetic regulation of circadian targets.

9.
Nat Commun ; 11(1): 5872, 2020 11 18.
Article in English | MEDLINE | ID: mdl-33208733

ABSTRACT

Substantial evidence implicates crosstalk between metabolic tissues and the immune system in the inception and progression of obesity. However, molecular regulators that orchestrate metaflammation both centrally and peripherally remains incompletely understood. Here, we identify myeloid Krüppel-like factor 2 (KLF2) as an essential regulator of obesity and its sequelae. In mice and humans, consumption of a fatty diet downregulates myeloid KLF2 levels. Under basal conditions, myeloid-specific KLF2 knockout mice (K2KO) exhibit increased feeding and weight gain. High-fat diet (HFD) feeding further exacerbates the K2KO metabolic disease phenotype. Mechanistically, loss of myeloid KLF2 increases metaflammation in peripheral and central tissues. A combination of pair-feeding, bone marrow-transplant, and microglial ablation implicate central and peripheral contributions to K2KO-induced metabolic dysfunction observed. Finally, overexpression of myeloid KLF2 protects mice from HFD-induced obesity and insulin resistance. Together, these data establish myeloid KLF2 as a nodal regulator of central and peripheral metabolic inflammation in homeostasis and disease.


Subject(s)
Kruppel-Like Transcription Factors/immunology , Metabolic Diseases/immunology , Myeloid Cells/immunology , Obesity/immunology , Animals , Central Nervous System/immunology , Diet, High-Fat/adverse effects , Eating , Humans , Inflammation , Insulin Resistance , Kruppel-Like Transcription Factors/genetics , Male , Metabolic Diseases/genetics , Metabolic Diseases/metabolism , Metabolic Diseases/physiopathology , Mice , Mice, Knockout , Obesity/etiology , Obesity/genetics , Obesity/physiopathology , Peripheral Nervous System/immunology
10.
Sci Rep ; 10(1): 14348, 2020 09 01.
Article in English | MEDLINE | ID: mdl-32873817

ABSTRACT

Chronic exposure to particulate matter < 2.5µ (PM2.5) has been linked to cardiopulmonary disease. Tissue-resident (TR) alveolar macrophages (AΦ) are long-lived, self-renew and critical to the health impact of inhalational insults. There is an inadequate understanding of the impact of PM2.5 exposure on the nature/time course of transcriptional responses, self-renewal of AΦ, and the contribution from bone marrow (BM) to this population. Accordingly, we exposed chimeric (CD45.2/CD45.1) mice to concentrated PM2.5 or filtered air (FA) to evaluate the impact on these end-points. PM2.5 exposure for 4-weeks induced an influx of BM-derived monocytes into the lungs with no contribution to the overall TR-AΦ pool. Chronic (32-weeks) PM2.5 exposure on the other hand while associated with increased recruitment of BM-derived monocytes and their incorporation into the AΦ population, resulted in enhanced apoptosis and decreased proliferation of TR-AΦ. RNA-seq analysis of isolated TR-AΦ and BM-AΦ from 4- and 32-weeks exposed mice revealed a unique time-dependent pattern of differentially expressed genes. PM2.5 exposure resulted in altered histological changes in the lungs, a reduced alveolar fraction which corresponded to protracted lung inflammation. Our findings suggest a time-dependent entrainment of BM-derived monocytes into the AΦ population of PM2.5 exposed mice, that together with enhanced apoptosis of TR-AΦ and reorganization of transcriptional responses, could collectively contribute to the perpetuation of chronic inflammation.


Subject(s)
Air Pollution/adverse effects , Bone Marrow Cells/cytology , Inhalation Exposure/adverse effects , Macrophages, Alveolar/immunology , Monocytes/immunology , Pneumonia/immunology , Air Pollutants/adverse effects , Animals , Apoptosis/drug effects , Cell Proliferation/drug effects , Gene Expression Regulation/drug effects , Lung/pathology , Male , Mice , Mice, Inbred C57BL , Particulate Matter/adverse effects
11.
Cell Rep ; 32(13): 108172, 2020 09 29.
Article in English | MEDLINE | ID: mdl-32997990

ABSTRACT

Nuclear actin has been elusive due to the lack of knowledge about molecular mechanisms. From actin-containing chromatin remodeling complexes, we discovered an arginine mono-methylation mark on an evolutionarily conserved R256 residue of actin (R256me1). Actin R256 mutations in yeast affect nuclear functions and cause diseases in human. Interestingly, we show that an antibody specific for actin R256me1 preferentially stains nuclear actin over cytoplasmic actin in yeast, mouse, and human cells. We also show that actin R256me1 is regulated by protein arginine methyl transferase-5 (PRMT5) in HEK293 cells. A genome-wide survey of actin R256me1 mark provides a landscape for nuclear actin correlated with transcription. Further, gene expression and protein interaction studies uncover extensive correlations between actin R256me1 and active transcription. The discovery of actin R256me1 mark suggests a fundamental mechanism to distinguish nuclear actin from cytoplasmic actin through post-translational modification (PTM) and potentially implicates an actin PTM mark in transcription and human diseases.


Subject(s)
Actins/metabolism , Protein Processing, Post-Translational/physiology , Transcription Factors/metabolism , Animals , Humans , Methylation , Mice
12.
J Clin Invest ; 130(11): 6034-6040, 2020 11 02.
Article in English | MEDLINE | ID: mdl-32780721

ABSTRACT

Air pollution involving particulate matter smaller than 2.5 µm in size (PM2.5) is the world's leading environmental risk factor contributing to mortality through cardiometabolic pathways. In this study, we modeled early life exposure using chow-fed C57BL/6J male mice that were exposed to real-world inhaled, concentrated PM2.5 (~10 times ambient levels/~60-120 µg/m3) or filtered air over a 14-week period. We investigated the effects of PM2.5 on phenotype, the transcriptome, and chromatin accessibility and compared these with the effects of a prototypical high-fat diet (HFD) as well as cessation of exposure on phenotype reversibility. Exposure to PM2.5 impaired glucose and insulin tolerance and reduced energy expenditure and 18FDG-PET uptake in brown adipose tissue. Multiple differentially expressed gene clusters in pathways involving metabolism and circadian rhythm were noted in insulin-responsive tissues. Although the magnitude of transcriptional change detected with PM2.5 exposure was lower than that observed with a HFD, the degree of alteration in chromatin accessibility after PM2.5 exposure was significant. The novel chromatin remodeler SMARCA5 (SWI/SNF complex) was regulated in response to PM2.5 exposure, the cessation of which was associated with a reversal of insulin resistance and restoration of chromatin accessibility and nucleosome positioning near transcription start sites, as well as a reversal of exposure-induced changes in the transcriptome, including SMARCA5. These changes indicate pliable epigenetic control mechanisms following cessation of exposure.


Subject(s)
Adipose Tissue, Brown , Air Pollutants/toxicity , Diet, High-Fat/adverse effects , Energy Metabolism/drug effects , Environmental Exposure/adverse effects , Insulin Resistance , Adenosine Triphosphatases/metabolism , Adipose Tissue, Brown/diagnostic imaging , Adipose Tissue, Brown/metabolism , Animals , Chromatin Assembly and Disassembly/drug effects , Chromosomal Proteins, Non-Histone/metabolism , Fluorodeoxyglucose F18/pharmacology , Mice , Positron-Emission Tomography , Transcriptome/drug effects
13.
Environ Epigenet ; 6(1): dvaa005, 2020 Jan.
Article in English | MEDLINE | ID: mdl-32551139

ABSTRACT

Preterm birth (PTB) is a major public health challenge, and novel, sensitive approaches to predict PTB are still evolving. Epigenomic markers are being explored as biomarkers of PTB because of their molecular stability compared to gene expression. This approach is also relatively new compared to gene-based diagnostics, which relies on mutations or single nucleotide polymorphisms. The fundamental principle of epigenome diagnostics is that epigenetic reprogramming in the target tissue (e.g. placental tissue) might be captured by more accessible surrogate tissue (e.g. blood) using biochemical epigenome assays on circulating DNA that incorporate methylation, histone modifications, nucleosome positioning, and/or chromatin accessibility. Epigenomic-based biomarkers may hold great potential for early identification of the majority of PTBs that are not associated with genetic variants or mutations. In this review, we discuss recent advances made in the development of epigenome assays focusing on its potential exploration for association and prediction of PTB. We also summarize population-level cohort studies conducted in the USA and globally that provide opportunities for genetic and epigenetic marker development for PTB. In addition, we summarize publicly available epigenome resources and published PTB studies. We particularly focus on ongoing genome-wide DNA methylation and epigenome-wide association studies. Finally, we review the limitations of current research, the importance of establishing a comprehensive biobank, and possible directions for future studies in identifying effective epigenome biomarkers to enhance health outcomes for pregnant women at risk of PTB and their infants.

14.
Tob Control ; 29(Suppl 2): s80-s89, 2020 02.
Article in English | MEDLINE | ID: mdl-31852817

ABSTRACT

OBJECTIVE: We investigated the effects of chronic waterpipe (WP) smoke on pulmonary function and immune response in a murine model using a research-grade WP and the effects of acute exposure on the regulation of immediate-early genes (IEGs). METHODS: WP smoke was generated using three WP smoke puffing regimens based on the Beirut regimen. WP smoke samples generated under these puffing regimens were quantified for nicotine concentration. Mice were chronically exposed for 6 months followed by assessment of pulmonary function and airway inflammation. Transcriptomic analysis using RNAseq was conducted after acute exposure to characterise the IEG response. These biomarkers were then compared with those generated after exposure to dry smoke (without water added to the WP bowl). RESULTS: We determined that nicotine composition in WP smoke ranged from 0.4 to 2.5 mg per puffing session. The lung immune response was sensitive to the incremental severity of chronic exposure, with modest decreases in airway inflammatory cells and chemokine levels compared with air-exposed controls. Pulmonary function was unmodified by chronic WP exposure. Acute WP exposure was found to activate the immune response and identified known and novel IEG as potential biomarkers of WP exposure. CONCLUSION: Chronic exposure to WP smoke leads to immune suppression without significant changes to pulmonary function. Transcriptomic analysis of the lung after acute exposure to WP smoke showed activation of the immune response and revealed IEGs that are common to WP and dry smoke, as well as pools of IEGs unique to each exposure, identifying potential biomarkers specific to WP exposure.


Subject(s)
Genes, Immediate-Early , Lung/immunology , Nicotine/analysis , Water Pipe Smoking/immunology , Animals , Biomarkers/metabolism , Female , Mice , Mice, Inbred C57BL , Smoking Water Pipes
15.
Epigenetics Chromatin ; 11(1): 13, 2018 03 29.
Article in English | MEDLINE | ID: mdl-29598828

ABSTRACT

BACKGROUND: Eukaryotic transcription is regulated through two complexes, the general transcription factor IID (TFIID) and the coactivator Spt-Ada-Gcn5 acetyltransferase (SAGA). Recent findings confirm that both TFIID and SAGA contribute to the synthesis of nearly all transcripts and are recruited genome-wide in yeast. However, how this broad recruitment confers selectivity under specific conditions remains an open question. RESULTS: Here we find that the SAGA/TREX-2 subunit Sus1 associates with upstream regulatory regions of many yeast genes and that heat shock drastically changes Sus1 binding. While Sus1 binding to TFIID-dominated genes is not affected by temperature, its recruitment to SAGA-dominated genes and RP genes is significantly disturbed under heat shock, with Sus1 relocated to environmental stress-responsive genes in these conditions. Moreover, in contrast to recent results showing that SAGA deubiquitinating enzyme Ubp8 is dispensable for RNA synthesis, genomic run-on experiments demonstrate that Sus1 contributes to synthesis and stability of a wide range of transcripts. CONCLUSIONS: Our study provides support for a model in which SAGA/TREX-2 factor Sus1 acts as a global transcriptional regulator in yeast but has differential activity at yeast genes as a function of their transcription rate or during stress conditions.


Subject(s)
Nuclear Proteins/metabolism , RNA-Binding Proteins/metabolism , Saccharomyces cerevisiae Proteins/metabolism , Saccharomyces cerevisiae/growth & development , Stress, Physiological , Transcription, Genetic , Gene Expression Regulation, Fungal , Promoter Regions, Genetic , Protein Binding , RNA, Fungal/metabolism , RNA, Messenger/metabolism , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae/metabolism , Saccharomyces cerevisiae Proteins/genetics , Trans-Activators/genetics , Trans-Activators/metabolism
16.
Genome Res ; 2018 Feb 14.
Article in English | MEDLINE | ID: mdl-29444801

ABSTRACT

Gene expression is controlled by a variety of proteins that interact with the genome. Their precise organization and mechanism of action at every promoter remains to be worked out. To better understand the physical interplay among genome-interacting proteins, we examined the temporal binding of a functionally diverse subset of these proteins: nucleosomes (H3), H2AZ (Htz1), SWR (Swr1), RSC (Rsc1, Rsc3, Rsc58, Rsc6, Rsc9, Sth1), SAGA (Spt3, Spt7, Ubp8, Sgf11), Hsf1, TFIID (Spt15/TBP and Taf1), TFIIB (Sua7), TFIIH (Ssl2), FACT (Spt16), Pol II (Rpb3), and Pol II carboxyl-terminal domain (CTD) phosphorylation at serines 2, 5, and 7. They were examined under normal and acute heat shock conditions, using the ultrahigh resolution genome-wide ChIP-exo assay in Saccharomyces cerevisiae Our findings reveal a precise positional organization of proteins bound at most genes, some of which rapidly reorganize within minutes of heat shock. This includes more precise positional transitions of Pol II CTD phosphorylation along the 5' ends of genes than previously seen. Reorganization upon heat shock includes colocalization of SAGA with promoter-bound Hsf1, a change in RSC subunit enrichment from gene bodies to promoters, and Pol II accumulation within promoter/+1 nucleosome regions. Most of these events are widespread and not necessarily coupled to changes in gene expression. Together, these findings reveal protein-genome interactions that are robustly reprogrammed in precise and uniform ways far beyond what is elicited by changes in gene expression.

17.
Mol Cell ; 64(4): 815-825, 2016 11 17.
Article in English | MEDLINE | ID: mdl-27840029

ABSTRACT

The five-subunit yeast Paf1 complex (Paf1C) regulates all stages of transcription and is critical for the monoubiquitylation of histone H2B (H2Bub), a modification that broadly influences chromatin structure and eukaryotic transcription. Here, we show that the histone modification domain (HMD) of Paf1C subunit Rtf1 directly interacts with the ubiquitin conjugase Rad6 and stimulates H2Bub independently of transcription. We present the crystal structure of the Rtf1 HMD and use site-specific, in vivo crosslinking to identify a conserved Rad6 interaction surface. Utilizing ChIP-exo analysis, we define the localization patterns of the H2Bub machinery at high resolution and demonstrate the importance of Paf1C in targeting the Rtf1 HMD, and thereby H2Bub, to its appropriate genomic locations. Finally, we observe HMD-dependent stimulation of H2Bub in a transcription-free, reconstituted in vitro system. Taken together, our results argue for an active role for Paf1C in promoting H2Bub and ensuring its proper localization in vivo.


Subject(s)
Gene Expression Regulation, Fungal , Histones/metabolism , Saccharomyces cerevisiae Proteins/metabolism , Saccharomyces cerevisiae/metabolism , TATA-Box Binding Protein/metabolism , Ubiquitin-Conjugating Enzymes/metabolism , Amino Acid Motifs , Binding Sites , Chromosomal Proteins, Non-Histone/genetics , Chromosomal Proteins, Non-Histone/metabolism , Cross-Linking Reagents/chemistry , Crystallography, X-Ray , Formaldehyde/chemistry , Histones/chemistry , Histones/genetics , Models, Molecular , Nuclear Proteins/genetics , Nuclear Proteins/metabolism , Protein Binding , Protein Conformation, alpha-Helical , Protein Interaction Domains and Motifs , RNA Polymerase II/genetics , RNA Polymerase II/metabolism , Recombinant Proteins/chemistry , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae Proteins/chemistry , Saccharomyces cerevisiae Proteins/genetics , TATA-Box Binding Protein/chemistry , TATA-Box Binding Protein/genetics , Transcription, Genetic , Transcriptional Elongation Factors/genetics , Transcriptional Elongation Factors/metabolism , Ubiquitin-Conjugating Enzymes/chemistry , Ubiquitin-Conjugating Enzymes/genetics , Ubiquitination
18.
EMBO J ; 35(13): 1465-82, 2016 07 01.
Article in English | MEDLINE | ID: mdl-27225933

ABSTRACT

Nap1 is a histone chaperone involved in the nuclear import of H2A-H2B and nucleosome assembly. Here, we report the crystal structure of Nap1 bound to H2A-H2B together with in vitro and in vivo functional studies that elucidate the principles underlying Nap1-mediated H2A-H2B chaperoning and nucleosome assembly. A Nap1 dimer provides an acidic binding surface and asymmetrically engages a single H2A-H2B heterodimer. Oligomerization of the Nap1-H2A-H2B complex results in burial of surfaces required for deposition of H2A-H2B into nucleosomes. Chromatin immunoprecipitation-exonuclease (ChIP-exo) analysis shows that Nap1 is required for H2A-H2B deposition across the genome. Mutants that interfere with Nap1 oligomerization exhibit severe nucleosome assembly defects showing that oligomerization is essential for the chaperone function. These findings establish the molecular basis for Nap1-mediated H2A-H2B deposition and nucleosome assembly.


Subject(s)
Histones/chemistry , Histones/metabolism , Nucleosome Assembly Protein 1/chemistry , Nucleosome Assembly Protein 1/metabolism , Nucleosomes/metabolism , Saccharomyces cerevisiae Proteins/chemistry , Saccharomyces cerevisiae Proteins/metabolism , Chromatin Immunoprecipitation , Crystallography, X-Ray , DNA Mutational Analysis , Models, Molecular , Nucleosome Assembly Protein 1/genetics , Protein Binding , Protein Conformation , Protein Multimerization , Saccharomyces cerevisiae/chemistry , Saccharomyces cerevisiae/metabolism , Saccharomyces cerevisiae Proteins/genetics
19.
Mol Cell Biol ; 36(1): 157-72, 2016 Jan 01.
Article in English | MEDLINE | ID: mdl-26503782

ABSTRACT

Erythroid development and differentiation from multiprogenitor cells into red blood cells requires precise transcriptional regulation. Key erythroid transcription factors, GATA1 and TAL1, cooperate, along with other proteins, to regulate many aspects of this process. How GATA1 and TAL1 are juxtaposed along the DNA and their cognate DNA binding site across the mouse genome remains unclear. We applied high-resolution ChIP-exo (chromatin immunoprecipitation followed by 5'-to-3' exonuclease treatment and then massively parallel DNA sequencing) to GATA1 and TAL1 to study their positional organization across the mouse genome during GATA1-dependent maturation. Two complementary methods, MultiGPS and peak pairing, were used to determine high-confidence binding locations by ChIP-exo. We identified ∼10,000 GATA1 and ∼15,000 TAL1 locations, which were essentially confirmed by ChIP-seq (chromatin immunoprecipitation followed by massively parallel DNA sequencing). Of these, ∼4,000 locations were bound by both GATA1 and TAL1. About three-quarters of them were tightly linked to a partial E-box located 7 or 8 bp upstream of a WGATAA motif. Both TAL1 and GATA1 generated distinct characteristic ChIP-exo peaks around WGATAA motifs that reflect their positional arrangement within a complex. We show that TAL1 and GATA1 form a precisely organized complex at a compound motif consisting of a TG 7 or 8 bp upstream of a WGATAA motif across thousands of genomic locations.


Subject(s)
Basic Helix-Loop-Helix Transcription Factors/metabolism , Cell Differentiation/physiology , GATA1 Transcription Factor/metabolism , Gene Expression Regulation/physiology , Genomics , Proto-Oncogene Proteins/metabolism , Animals , Base Sequence , Chromatin Immunoprecipitation/methods , DNA/metabolism , Mice , Sequence Analysis, DNA/methods , T-Cell Acute Lymphocytic Leukemia Protein 1 , Transcription Factors/metabolism
20.
Genes Dev ; 29(18): 1942-54, 2015 Sep 15.
Article in English | MEDLINE | ID: mdl-26385964

ABSTRACT

The 137 ribosomal protein genes (RPGs) of Saccharomyces provide a model for gene coregulation. We examined the positional and functional organization of their regulators (Rap1 [repressor activator protein 1], Fhl1, Ifh1, Sfp1, and Hmo1), the transcription machinery (TFIIB, TFIID, and RNA polymerase II), and chromatin at near-base-pair resolution using ChIP-exo, as RPGs are coordinately reprogrammed. Where Hmo1 is enriched, Fhl1, Ifh1, Sfp1, and Hmo1 cross-linked broadly to promoter DNA in an RPG-specific manner and demarcated by general minor groove widening. Importantly, Hmo1 extended 20-50 base pairs (bp) downstream from Fhl1. Upon RPG repression, Fhl1 remained in place. Hmo1 dissociated, which was coupled to an upstream shift of the +1 nucleosome, as reflected by the Hmo1 extension and core promoter region. Fhl1 and Hmo1 may create two regulatable and positionally distinct barriers, against which chromatin remodelers position the +1 nucleosome into either an activating or a repressive state. Consistent with in vitro studies, we found that specific TFIID subunits, in addition to cross-linking at the core promoter, made precise cross-links at Rap1 sites, which we interpret to reflect native Rap1-TFIID interactions. Our findings suggest how sequence-specific DNA binding regulates nucleosome positioning and transcription complex assembly >300 bp away and how coregulation coevolved with coding sequences.


Subject(s)
Gene Expression Regulation, Fungal , Ribosomal Proteins/genetics , Saccharomyces cerevisiae Proteins/genetics , Nucleosomes/metabolism , Ribosomal Proteins/metabolism , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae/metabolism , Saccharomyces cerevisiae Proteins/metabolism
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