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Moyung K, Li Y, Hartemink AJ, MacAlpine DM. Genome-wide nucleosome and transcription factor responses to genetic perturbations reveal chromatin-mediated mechanisms of transcriptional regulation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.24.595391. [PMID: 38826400 PMCID: PMC11142231 DOI: 10.1101/2024.05.24.595391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Epigenetic mechanisms contribute to gene regulation by altering chromatin accessibility through changes in transcription factor (TF) and nucleosome occupancy throughout the genome. Despite numerous studies focusing on changes in gene expression, the intricate chromatin-mediated regulatory code remains largely unexplored on a comprehensive scale. We address this by employing a factor-agnostic, reverse-genetics approach that uses MNase-seq to capture genome-wide TF and nucleosome occupancies in response to the individual deletion of 201 transcriptional regulators in Saccharomyces cerevisiae, thereby assaying nearly one million mutant-gene interactions. We develop a principled approach to identify and quantify chromatin changes genome-wide, observing differences in TF and nucleosome occupancy that recapitulate well-established pathways identified by gene expression data. We also discover distinct chromatin signatures associated with the up- and downregulation of genes, and use these signatures to reveal regulatory mechanisms previously unexplored in expression-based studies. Finally, we demonstrate that chromatin features are predictive of transcriptional activity and leverage these features to reconstruct chromatin-based transcriptional regulatory networks. Overall, these results illustrate the power of an approach combining genetic perturbation with high-resolution epigenomic profiling; the latter enables a close examination of the interplay between TFs and nucleosomes genome-wide, providing a deeper, more mechanistic understanding of the complex relationship between chromatin organization and transcription.
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Affiliation(s)
- Kevin Moyung
- Program in Computational Biology and Bioinformatics, Duke University, Durham, NC 27708
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710
| | - Yulong Li
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710
- Department of Computer Science, Duke University, Durham, NC 27708
| | - Alexander J. Hartemink
- Program in Computational Biology and Bioinformatics, Duke University, Durham, NC 27708
- Department of Computer Science, Duke University, Durham, NC 27708
| | - David M. MacAlpine
- Program in Computational Biology and Bioinformatics, Duke University, Durham, NC 27708
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710
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2
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Abid D, Brent MR. NetProphet 3: a machine learning framework for transcription factor network mapping and multi-omics integration. Bioinformatics 2023; 39:7000334. [PMID: 36692138 PMCID: PMC9912366 DOI: 10.1093/bioinformatics/btad038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 01/11/2023] [Accepted: 01/18/2023] [Indexed: 01/25/2023] Open
Abstract
MOTIVATION Many methods have been proposed for mapping the targets of transcription factors (TFs) from gene expression data. It is known that combining outputs from multiple methods can improve performance. To date, outputs have been combined by using either simplistic formulae, such as geometric mean, or carefully hand-tuned formulae that may not generalize well to new inputs. Finally, the evaluation of accuracy has been challenging due to the lack of genome-scale, ground-truth networks. RESULTS We developed NetProphet3, which combines scores from multiple analyses automatically, using a tree boosting algorithm trained on TF binding location data. We also developed three independent, genome-scale evaluation metrics. By these metrics, NetProphet3 is more accurate than other commonly used packages, including NetProphet 2.0, when gene expression data from direct TF perturbations are available. Furthermore, its integration mode can forge a consensus network from gene expression data and TF binding location data. AVAILABILITY AND IMPLEMENTATION All data and code are available at https://zenodo.org/record/7504131#.Y7Wu3i-B2x8. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Dhoha Abid
- Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO 63110, USA.,Department of Computer Science and Engineering, Washington University, St. Louis, MO 63130, USA
| | - Michael R Brent
- Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO 63110, USA.,Department of Computer Science and Engineering, Washington University, St. Louis, MO 63130, USA.,Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110, USA
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3
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Pang X, Miao Z, Dong Y, Cheng H, Xin X, Wu Y, Han M, Su Y, Yuan J, Shao Y, Yan L, Li J. Dietary methionine restriction alleviates oxidative stress and inflammatory responses in lipopolysaccharide-challenged broilers at early age. Front Pharmacol 2023; 14:1120718. [PMID: 36874014 PMCID: PMC9975741 DOI: 10.3389/fphar.2023.1120718] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Accepted: 01/20/2023] [Indexed: 02/17/2023] Open
Abstract
In this study, we investigated the effect of dietary methionine restriction (MR) on the antioxidant function and inflammatory responses in lipopolysaccharide (LPS)-challenged broilers reared at high stocking density. A total of 504 one-day-old male Arbor Acre broiler chickens were randomly divided into four treatments: 1) CON group, broilers fed a basal diet; 2) LPS group, LPS-challenged broilers fed a basal diet; 3) MR1 group, LPS-challenged broilers fed a methionine-restricted diet (0.3% methionine); and 4) MR2 group, LPS-challenged broilers fed a methionine-restricted diet (0.4% methionine). LPS-challenged broilers were intraperitoneally injected with 1 mg/kg body weight (BW) of LPS at 17, 19, and 21 days of age, whereas the CON group was injected with sterile saline. The results showed that: LPS significantly increased the liver histopathological score (p < 0.05); LPS significantly decreased the serum total antioxidant capacity (T-AOC), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) activity at 3 h after injection (p < 0.05); the LPS group had a higher content of Interleukin (IL)-1β, IL-6, and tumor necrosis factor-α (TNF)-α, but a lower content of IL-10 than the CON group in serum (p < 0.05). Compared with the LPS group, the MR1 diet increased catalase (CAT), SOD, and T-AOC, and the MR2 diet increased SOD and T-AOC at 3 h after injection in serum (p < 0.05). Only MR2 group displayed a significantly decreased liver histopathological score (p < 0.05) at 3 h, while MR1 and MR2 groups did so at 8 h. Both MR diets significantly decreased serum LPS, CORT, IL-1β, IL-6, and TNF-α contents, but increased IL-10 content (p < 0.05). Moreover, the MR1 group displayed significantly increased expression of nuclear factor erythroid 2-related factor 2 (Nrf2), CAT, and GSH-Px at 3 h; the MR2 group had a higher expression of Kelch-like ECH-associated protein 1 (Keap1), SOD, and GSH-Px at 8 h (p < 0.05). In summary, MR can improve antioxidant capacity, immunological stress, and liver health in LPS-challenged broilers. The MR1 and MR2 groups experienced similar effects on relieving stress; however, MR1 alleviated oxidative stress more rapidly. It is suggested that precise regulation of methionine levels in poultry with stress may improve the immunity of broilers, reduce feed production costs, and increase production efficiency in the poultry industry.
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Affiliation(s)
- Xiyuan Pang
- College of Animal Sciences, Shanxi Agricultural University, Taigu, China
| | - Zhiqiang Miao
- College of Animal Sciences, Shanxi Agricultural University, Taigu, China
| | - Yuanyang Dong
- College of Animal Sciences, Shanxi Agricultural University, Taigu, China
| | - Huiyu Cheng
- College of Animal Sciences, Shanxi Agricultural University, Taigu, China
| | - Xiangqi Xin
- College of Animal Sciences, Shanxi Agricultural University, Taigu, China
| | - Yuan Wu
- College of Animal Sciences, Shanxi Agricultural University, Taigu, China
| | - Miaomiao Han
- College of Animal Sciences, Shanxi Agricultural University, Taigu, China
| | - Yuan Su
- College of Animal Sciences, Shanxi Agricultural University, Taigu, China
| | - Jianmin Yuan
- College of Animal Sciences and Technology, China Agricultural University, Beijing, China
| | - Yuxin Shao
- Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
| | - Lei Yan
- New Hope Liuhe Co.,Ltd., Beijing, China
| | - Jianhui Li
- College of Animal Sciences, Shanxi Agricultural University, Taigu, China
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4
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Impact of serine and serine synthesis genes on H2S release in Saccharomyces cerevisiae during wine fermentation. Food Microbiol 2022; 103:103961. [DOI: 10.1016/j.fm.2021.103961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Revised: 10/26/2021] [Accepted: 12/01/2021] [Indexed: 11/16/2022]
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5
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Shrivastava M, Feng J, Coles M, Clark B, Islam A, Dumeaux V, Whiteway M. Modulation of the complex regulatory network for methionine biosynthesis in fungi. Genetics 2021; 217:6078591. [PMID: 33724418 DOI: 10.1093/genetics/iyaa049] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Accepted: 12/07/2020] [Indexed: 01/19/2023] Open
Abstract
The assimilation of inorganic sulfate and the synthesis of the sulfur-containing amino acids methionine and cysteine is mediated by a multibranched biosynthetic pathway. We have investigated this circuitry in the fungal pathogen Candida albicans, which is phylogenetically intermediate between the filamentous fungi and Saccharomyces cerevisiae. In S. cerevisiae, this pathway is regulated by a collection of five transcription factors (Met4, Cbf1, Met28, and Met31/Met32), while in the filamentous fungi the pathway is controlled by a single Met4-like factor. We found that in C. albicans, the Met4 ortholog is also a core regulator of methionine biosynthesis, where it functions together with Cbf1. While C. albicans encodes this Met4 protein, a Met4 paralog designated Met28 (Orf19.7046), and a Met31 protein, deletion, and activation constructs suggest that of these proteins only Met4 is actually involved in the regulation of methionine biosynthesis. Both Met28 and Met31 are linked to other functions; Met28 appears essential, and Met32 appears implicated in the regulation of genes of central metabolism. Therefore, while S. cerevisiae and C. albicans share Cbf1 and Met4 as central elements of the methionine biosynthesis control, the other proteins that make up the circuit in S. cerevisiae are not members of the C. albicans control network, and so the S. cerevisiae circuit likely represents a recently evolved arrangement.
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Affiliation(s)
| | - Jinrong Feng
- Medical School, Nantong University, Nangtong, Jiangsu, China
| | - Mark Coles
- Depatment of Biology, Concordia University, Montreal, QC, Canada
| | - Benjamin Clark
- Depatment of Biology, Concordia University, Montreal, QC, Canada
| | - Amjad Islam
- Depatment of Biology, Concordia University, Montreal, QC, Canada
| | - Vanessa Dumeaux
- Depatment of Biology, Concordia University, Montreal, QC, Canada
| | - Malcolm Whiteway
- Depatment of Biology, Concordia University, Montreal, QC, Canada
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Alqahtani FM, Handy ST, Sutton CL, Farone MB. Combining Genome-Wide Gene Expression Analysis (RNA-seq) and a Gene Editing Platform (CRISPR-Cas9) to Uncover the Selectively Pro-oxidant Activity of Aurone Compounds Against Candida albicans. Front Microbiol 2021; 12:708267. [PMID: 34335543 PMCID: PMC8319688 DOI: 10.3389/fmicb.2021.708267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 06/23/2021] [Indexed: 11/13/2022] Open
Abstract
Candida albicans is the major fungal cause of healthcare-associated bloodstream infections worldwide with a 40% mortality rate. The scarcity of antifungal treatments due to the eukaryotic origin of fungal cells has challenged the development of selectively antifungal drugs. In an attempt to identify novel antifungal agents, aurones SH1009 and SH9051, as synthetically bioactive compounds, have been recently documented as anti-Candida agents. Since the molecular mechanisms behind the inhibitory activities of these aurones in C. albicans are unclear, this study aimed to determine the comprehensive cellular processes affected by these aurones and their molecular targets. Genome-wide transcriptional analysis of SH1009- and SH9051-treated C. albicans revealed uniquely repressed expression in different metabolic pathways, particularly trehalose and sulfur amino acid metabolic processes for SH1009 and SH9051, respectively. In contrast, the most commonly enriched process for both aurones was the up-regulation of RNA processing and ribosomal cleavages as an indicator of high oxidative stress, suggesting that a common aspect in the chemical structure of both aurones led to pro-oxidative properties. Additionally, uniquely induced responses (iron ion homeostasis for SH1009 and arginine biosynthesis for SH9051) garnered attention on key roles for the aurone functional groups. Deletion of the transcription factor for the trehalose biosynthesis pathway, Tye7p, resulted in an SH1009-resistant mutant, which also exhibited low trehalose content, validating the primary molecular target of SH1009. Aurone SH9051 uniquely simulated an exogenous supply of methionine or cysteine, leading to sulfur amino acid catabolism as evidenced by quantifying an overproduction of sulfite. Phenyl aurone, the common structure of aurones, contributed proportionally in the pro-oxidative activity through ferric ion reduction effects leading to high ROS levels. Our results determined selective and novel molecular mechanisms for aurone SH1009 and also elucidated the diverse cellular effects of different aurones based on functional groups.
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Affiliation(s)
- Fatmah M Alqahtani
- Department of Biology, Middle Tennessee State University, Murfreesboro, TN, United States
| | - Scott T Handy
- Department of Chemistry, Middle Tennessee State University, Murfreesboro, TN, United States
| | - Caleb L Sutton
- Department of Biology, Middle Tennessee State University, Murfreesboro, TN, United States
| | - Mary B Farone
- Department of Biology, Middle Tennessee State University, Murfreesboro, TN, United States
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7
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Liu Y, Lin Y, Guo Y, Wu F, Zhang Y, Qi X, Wang Z, Wang Q. Stress tolerance enhancement via SPT15 base editing in Saccharomyces cerevisiae. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:155. [PMID: 34229745 PMCID: PMC8259078 DOI: 10.1186/s13068-021-02005-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 06/26/2021] [Indexed: 05/12/2023]
Abstract
BACKGROUND Saccharomyces cerevisiae is widely used in traditional brewing and modern fermentation industries to produce biofuels, chemicals and other bioproducts, but challenged by various harsh industrial conditions, such as hyperosmotic, thermal and ethanol stresses. Thus, its stress tolerance enhancement has been attracting broad interests. Recently, CRISPR/Cas-based genome editing technology offers unprecedented tools to explore genetic modifications and performance improvement of S. cerevisiae. RESULTS Here, we presented that the Target-AID (activation-induced cytidine deaminase) base editor of enabling C-to-T substitutions could be harnessed to generate in situ nucleotide changes on the S. cerevisiae genome, thereby introducing protein point mutations in cells. The general transcription factor gene SPT15 was targeted, and total 36 mutants with diversified stress tolerances were obtained. Among them, the 18 tolerant mutants against hyperosmotic, thermal and ethanol stresses showed more than 1.5-fold increases of fermentation capacities. These mutations were mainly enriched at the N-terminal region and the convex surface of the saddle-shaped structure of Spt15. Comparative transcriptome analysis of three most stress-tolerant (A140G, P169A and R238K) and two most stress-sensitive (S118L and L214V) mutants revealed common and distinctive impacted global transcription reprogramming and transcriptional regulatory hubs in response to stresses, and these five amino acid changes had different effects on the interactions of Spt15 with DNA and other proteins in the RNA Polymerase II transcription machinery according to protein structure alignment analysis. CONCLUSIONS Taken together, our results demonstrated that the Target-AID base editor provided a powerful tool for targeted in situ mutagenesis in S. cerevisiae and more potential targets of Spt15 residues for enhancing yeast stress tolerance.
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Affiliation(s)
- Yanfang Liu
- CAS Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yuping Lin
- CAS Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yufeng Guo
- CAS Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, China
| | - Fengli Wu
- CAS Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, China
| | - Yuanyuan Zhang
- CAS Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, China
| | - Xianni Qi
- CAS Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, China
| | - Zhen Wang
- CAS Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Qinhong Wang
- CAS Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, China
- University of Chinese Academy of Sciences, Beijing, China
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8
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Tran TQ, MacAlpine HK, Tripuraneni V, Mitra S, MacAlpine DM, Hartemink AJ. Linking the dynamics of chromatin occupancy and transcription with predictive models. Genome Res 2021; 31:1035-1046. [PMID: 33893157 PMCID: PMC8168580 DOI: 10.1101/gr.267237.120] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 04/19/2021] [Indexed: 12/30/2022]
Abstract
Though the sequence of the genome within each eukaryotic cell is essentially fixed, it exists within a complex and changing chromatin state. This state is determined, in part, by the dynamic binding of proteins to the DNA. These proteins—including histones, transcription factors (TFs), and polymerases—interact with one another, the genome, and other molecules to allow the chromatin to adopt one of exceedingly many possible configurations. Understanding how changing chromatin configurations associate with transcription remains a fundamental research problem. We sought to characterize at high spatiotemporal resolution the dynamic interplay between transcription and chromatin in response to cadmium stress. Whereas gene regulatory responses to environmental stress in yeast have been studied, how the chromatin state changes and how those changes connect to gene regulation remain unexplored. By combining MNase-seq and RNA-seq data, we found chromatin signatures of transcriptional activation and repression involving both nucleosomal and TF-sized DNA-binding factors. Using these signatures, we identified associations between chromatin dynamics and transcriptional regulation, not only for known cadmium response genes, but across the entire genome, including antisense transcripts. Those associations allowed us to develop generalizable models that predict dynamic transcriptional responses on the basis of dynamic chromatin signatures.
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Affiliation(s)
- Trung Q Tran
- Department of Computer Science, Duke University, Durham, North Carolina 27708, USA
| | - Heather K MacAlpine
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Vinay Tripuraneni
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Sneha Mitra
- Department of Computer Science, Duke University, Durham, North Carolina 27708, USA
| | - David M MacAlpine
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710, USA.,Center for Genomic and Computational Biology, Duke University, Durham, North Carolina 27708, USA
| | - Alexander J Hartemink
- Department of Computer Science, Duke University, Durham, North Carolina 27708, USA.,Center for Genomic and Computational Biology, Duke University, Durham, North Carolina 27708, USA
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Hackett SR, Baltz EA, Coram M, Wranik BJ, Kim G, Baker A, Fan M, Hendrickson DG, Berndl M, McIsaac RS. Learning causal networks using inducible transcription factors and transcriptome-wide time series. Mol Syst Biol 2021; 16:e9174. [PMID: 32181581 PMCID: PMC7076914 DOI: 10.15252/msb.20199174] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 02/13/2020] [Accepted: 02/19/2020] [Indexed: 11/27/2022] Open
Abstract
We present IDEA (the Induction Dynamics gene Expression Atlas), a dataset constructed by independently inducing hundreds of transcription factors (TFs) and measuring timecourses of the resulting gene expression responses in budding yeast. Each experiment captures a regulatory cascade connecting a single induced regulator to the genes it causally regulates. We discuss the regulatory cascade of a single TF, Aft1, in detail; however, IDEA contains > 200 TF induction experiments with 20 million individual observations and 100,000 signal‐containing dynamic responses. As an application of IDEA, we integrate all timecourses into a whole‐cell transcriptional model, which is used to predict and validate multiple new and underappreciated transcriptional regulators. We also find that the magnitudes of coefficients in this model are predictive of genetic interaction profile similarities. In addition to being a resource for exploring regulatory connectivity between TFs and their target genes, our modeling approach shows that combining rapid perturbations of individual genes with genome‐scale time‐series measurements is an effective strategy for elucidating gene regulatory networks.
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Affiliation(s)
| | | | | | | | - Griffin Kim
- Calico Life Sciences LLC, South San Francisco, CA, USA
| | - Adam Baker
- Calico Life Sciences LLC, South San Francisco, CA, USA
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10
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Rajakumar S, Suriyagandhi V, Nachiappan V. Impairment of MET transcriptional activators, MET4 and MET31 induced lipid accumulation in Saccharomyces cerevisiae. FEMS Yeast Res 2020; 20:5869667. [PMID: 32648914 DOI: 10.1093/femsyr/foaa039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 07/08/2020] [Indexed: 11/13/2022] Open
Abstract
The genes involved in the methionine pathway are closely associated with phospholipid homeostasis in yeast. The impact of the deletion of methionine (MET) transcriptional activators (MET31, MET32 and MET4) in lipid homeostasis is studied. Our lipid profiling data showed that aberrant phospholipid and neutral lipid accumulation occurred in met31∆ and met4∆ strains with low Met. The expression pattern of phospholipid biosynthetic genes such as CHO2, OPI3 and triacylglycerol (TAG) biosynthetic gene, DGA1 were upregulated in met31∆, and met4∆ strains when compared to wild type (WT). The accumulation of triacylglycerol and sterol esters (SE) content supports the concomitant increase in lipid droplets in met31∆ and met4∆ strains. However, excessive supplies of methionine (1 mM) in the cells lacking the MET transcriptional activators MET31 and MET4 ameliorates the abnormal lipogenesis and causes aberrant lipid accumulation. These findings implicate the methionine accessibility plays a pivotal role in lipid metabolism in the yeast model.
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Affiliation(s)
- Selvaraj Rajakumar
- Biomembrane Lab, Department of Biochemistry, School of Life Sciences, Bharathidasan University, Tiruchirappalli - 620 024, Tamil Nadu, India
| | - Vennila Suriyagandhi
- Biomembrane Lab, Department of Biochemistry, School of Life Sciences, Bharathidasan University, Tiruchirappalli - 620 024, Tamil Nadu, India
| | - Vasanthi Nachiappan
- Biomembrane Lab, Department of Biochemistry, School of Life Sciences, Bharathidasan University, Tiruchirappalli - 620 024, Tamil Nadu, India
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11
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Yoo SJ, Sohn MJ, Jeong DM, Kang HA. Short bZIP homologue of sulfur regulator Met4 from Ogataea parapolymorpha does not depend on DNA-binding cofactors for activating genes in sulfur starvation. Environ Microbiol 2019; 22:310-328. [PMID: 31680403 DOI: 10.1111/1462-2920.14849] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 10/29/2019] [Accepted: 10/30/2019] [Indexed: 11/28/2022]
Abstract
The acquisition of sulfur from environment and its assimilation is essential for fungal growth and activities. Here, we describe novel features of the regulatory network of sulfur metabolism in Ogataea parapolymorpha, a thermotolerant methylotrophic yeast with high resistance to harsh environmental conditions. A short bZIP protein (OpMet4p) of O. parapolymorpha, displaying the combined structural characteristics of yeast and filamentous fungal Met4 homologues, plays a key role as a master regulator of cell homeostasis during sulfur limitation, but also its function is required for the tolerance of various stresses. Domain swapping analysis, combined with deletion analysis of the regulatory domains and genes encoding OpCbf1p, OpMet28p, and OpMet32p, indicated that OpMet4p does not require the interaction with these DNA-binding cofactors to induce the expression of sulfur genes, unlike the Saccharomyces cerevisiae Met4p. ChIP analysis confirmed the notion that OpMet4p, which contains a canonical bZIP domain, can bind the target DNA in the absence of cofactors, similar to homologues in other filamentous fungi. Collectively, the identified unique features of the O. parapolymorpha regulatory network, as the first report on the sulfur regulation by a short yeast Met4 homologue, provide insights into conservation and divergence of the sulfur regulatory networks among diverse ascomycetous fungi.
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Affiliation(s)
- Su Jin Yoo
- Laboratory of Molecular Systems Biology, Department of Life Science, Chung-Ang University, Seoul, 06974, Korea
| | - Min Jeong Sohn
- Laboratory of Molecular Systems Biology, Department of Life Science, Chung-Ang University, Seoul, 06974, Korea
| | - Da Min Jeong
- Laboratory of Molecular Systems Biology, Department of Life Science, Chung-Ang University, Seoul, 06974, Korea
| | - Hyun Ah Kang
- Laboratory of Molecular Systems Biology, Department of Life Science, Chung-Ang University, Seoul, 06974, Korea
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12
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The Regulation of Cbf1 by PAS Kinase Is a Pivotal Control Point for Lipogenesis vs. Respiration in Saccharomyces cerevisiae. G3-GENES GENOMES GENETICS 2019; 9:33-46. [PMID: 30381292 PMCID: PMC6325914 DOI: 10.1534/g3.118.200663] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
PAS kinase 1 (Psk1) is a key regulator of respiration in Saccharomyces cerevisiae. Herein the molecular mechanisms of this regulation are explored through the characterization of its substrate, Centromere binding factor 1 (Cbf1). CBF1-deficient yeast displayed a significant decrease in cellular respiration, while PAS kinase-deficient yeast, or yeast harboring a Cbf1 phosphosite mutant (T211A) displayed a significant increase. Transmission electron micrographs showed an increased number of mitochondria in PAS kinase-deficient yeast consistent with the increase in respiration. Although the CBF1-deficient yeast did not appear to have an altered number of mitochondria, a mitochondrial proteomics study revealed significant differences in the mitochondrial composition of CBF1-deficient yeast including altered Atp3 levels, a subunit of the mitochondrial F1-ATP synthase complex. Both beta-galactosidase reporter assays and western blot analysis confirmed direct transcriptional control of ATP3 by Cbf1. In addition, we confirmed the regulation of yeast lipid genes LAC1 and LAG1 by Cbf1. The human homolog of Cbf1, Upstream transcription factor 1 (USF1), is also known to be involved in lipid biogenesis. Herein, we provide the first evidence for a role of USF1 in respiration since it appeared to complement Cbf1in vivo as determined by respiration phenotypes. In addition, we confirmed USF1 as a substrate of human PAS kinase (hPASK) in vitro. Combined, our data supports a model in which Cbf1/USF1 functions to partition glucose toward respiration and away from lipid biogenesis, while PAS kinase inhibits respiration in part through the inhibition of Cbf1/USF1.
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13
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Mosbach A, Edel D, Farmer AD, Widdison S, Barchietto T, Dietrich RA, Corran A, Scalliet G. Anilinopyrimidine Resistance in Botrytis cinerea Is Linked to Mitochondrial Function. Front Microbiol 2017; 8:2361. [PMID: 29250050 PMCID: PMC5714876 DOI: 10.3389/fmicb.2017.02361] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 11/15/2017] [Indexed: 12/11/2022] Open
Abstract
Crop protection anilinopyrimidine (AP) fungicides were introduced more than 20 years ago for the control of a range of diseases caused by ascomycete plant pathogens, and in particular for the control of gray mold caused by Botrytis cinerea. Although early mode of action studies suggested an inhibition of methionine biosynthesis, the molecular target of this class of fungicides was never fully clarified. Despite AP-specific resistance having been described in B. cinerea field isolates and in multiple other targeted species, the underlying resistance mechanisms were unknown. It was therefore expected that the genetic characterization of resistance mechanisms would permit the identification of the molecular target of these fungicides. In order to explore the widest range of possible resistance mechanisms, AP-resistant B. cinerea UV laboratory mutants were generated and the mutations conferring resistance were determined by combining whole-genome sequencing and reverse genetics. Genetic mapping from a cross between a resistant field isolate and a sensitive reference isolate was used in parallel and led to the identification of an additional molecular determinant not found from the characterized UV mutant collection. Together, these two approaches enabled the characterization of an unrivaled diversity of resistance mechanisms. In total, we report the elucidation of resistance-conferring mutations within nine individual genes, two of which are responsible for almost all instances of AP resistance in the field. All identified resistance-conferring genes encode proteins that are involved in mitochondrial processes, suggesting that APs primarily target the mitochondria. The functions of these genes and their possible interactions are discussed in the context of the potential mode of action for this important class of fungicides.
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Affiliation(s)
| | | | - Andrew D. Farmer
- National Center for Genome Resources, Santa Fe, NM, United States
- Syngenta Biotechnology Inc., Research Triangle Park, NC, United States
| | - Stephanie Widdison
- Syngenta Jealott's Hill International Research Centre, Bracknell, United Kingdom
| | | | | | - Andy Corran
- Syngenta Jealott's Hill International Research Centre, Bracknell, United Kingdom
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14
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Brown-Borg HM, Buffenstein R. Cutting back on the essentials: Can manipulating intake of specific amino acids modulate health and lifespan? Ageing Res Rev 2017; 39:87-95. [PMID: 27570078 DOI: 10.1016/j.arr.2016.08.007] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 08/24/2016] [Accepted: 08/24/2016] [Indexed: 12/26/2022]
Abstract
With few exceptions, nutritional and dietary interventions generally impact upon both old-age quality of life and longevity. The life prolonging effects, commonly observed with dietary restriction reportedly are linked to alterations in protein intake and specifically limiting the dietary intake of certain essential amino acids. There is however a paucity of data methodically evaluating the various essential amino acids on health- and lifespan and the mechanisms involved. Rodent diets containing either lower methionine content, or tryptophan, than that found in commercially available chow, appear to elicit beneficial effects. It is unclear whether all of these favorable effects associated with restricted intake of methionine and tryptophan are due to their specific unique properties or if restriction of other essential amino acids, or proteins in general, may produce similar results. Considerably more work remains to be done to elucidate the mechanisms by which limiting these vital molecules may delay the onset of age-associated diseases and improve quality of life at older ages.
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15
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Analysis of transcriptional profiles of Saccharomyces cerevisiae exposed to bisphenol A. Curr Genet 2016; 63:253-274. [DOI: 10.1007/s00294-016-0633-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 07/14/2016] [Accepted: 07/16/2016] [Indexed: 01/06/2023]
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16
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Saha A, Kizaki S, De D, Endo M, Kim KK, Sugiyama H. Examining cooperative binding of Sox2 on DC5 regulatory element upon complex formation with Pax6 through excess electron transfer assay. Nucleic Acids Res 2016; 44:e125. [PMID: 27229137 PMCID: PMC5001601 DOI: 10.1093/nar/gkw478] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 05/17/2016] [Indexed: 12/29/2022] Open
Abstract
Functional cooperativity among transcription factors on regulatory genetic elements is pivotal for milestone decision-making in various cellular processes including mammalian development. However, their molecular interaction during the cooperative binding cannot be precisely understood due to lack of efficient tools for the analyses of protein-DNA interaction in the transcription complex. Here, we demonstrate that photoinduced excess electron transfer assay can be used for analysing cooperativity of proteins in transcription complex using cooperative binding of Pax6 to Sox2 on the regulatory DNA element (DC5 enhancer) as an example. In this assay, (Br)U-labelled DC5 was introduced for the efficient detection of transferred electrons from Sox2 and Pax6 to the DNA, and guanine base in the complementary strand was replaced with hypoxanthine (I) to block intra-strand electron transfer at the Sox2-binding site. By examining DNA cleavage occurred as a result of the electron transfer process, from tryptophan residues of Sox2 and Pax6 to DNA after irradiation at 280 nm, we not only confirmed their binding to DNA but also observed their increased occupancy on DC5 with respect to that of Sox2 and Pax6 alone as a result of their cooperative interaction.
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Affiliation(s)
- Abhijit Saha
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto 606-8502, Japan
| | - Seiichiro Kizaki
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto 606-8502, Japan
| | - Debojyoti De
- Department of Molecular Cell Biology, Sungkyunkwan University, School of Medicine, Suwon 440-746, Korea
| | - Masayuki Endo
- Institute for Integrated Cell-Materials Sciences (iCeMS) Kyoto University, Yoshida-ushinomiyacho, Sakyo-Ku, Kyoto 606-8501, Japan
| | - Kyeong Kyu Kim
- Department of Molecular Cell Biology, Sungkyunkwan University, School of Medicine, Suwon 440-746, Korea
| | - Hiroshi Sugiyama
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto 606-8502, Japan Institute for Integrated Cell-Materials Sciences (iCeMS) Kyoto University, Yoshida-ushinomiyacho, Sakyo-Ku, Kyoto 606-8501, Japan
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17
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McIsaac RS, Lewis KN, Gibney PA, Buffenstein R. From yeast to human: exploring the comparative biology of methionine restriction in extending eukaryotic life span. Ann N Y Acad Sci 2016; 1363:155-70. [DOI: 10.1111/nyas.13032] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 01/25/2016] [Accepted: 01/27/2016] [Indexed: 12/19/2022]
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18
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Identifying genetic modulators of the connectivity between transcription factors and their transcriptional targets. Proc Natl Acad Sci U S A 2016; 113:E1835-43. [PMID: 26966232 DOI: 10.1073/pnas.1517140113] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Regulation of gene expression by transcription factors (TFs) is highly dependent on genetic background and interactions with cofactors. Identifying specific context factors is a major challenge that requires new approaches. Here we show that exploiting natural variation is a potent strategy for probing functional interactions within gene regulatory networks. We developed an algorithm to identify genetic polymorphisms that modulate the regulatory connectivity between specific transcription factors and their target genes in vivo. As a proof of principle, we mapped connectivity quantitative trait loci (cQTLs) using parallel genotype and gene expression data for segregants from a cross between two strains of the yeast Saccharomyces cerevisiae We identified a nonsynonymous mutation in the DIG2 gene as a cQTL for the transcription factor Ste12p and confirmed this prediction empirically. We also identified three polymorphisms in TAF13 as putative modulators of regulation by Gcn4p. Our method has potential for revealing how genetic differences among individuals influence gene regulatory networks in any organism for which gene expression and genotype data are available along with information on binding preferences for transcription factors.
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19
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Comprehensive Analysis of the SUL1 Promoter of Saccharomyces cerevisiae. Genetics 2016; 203:191-202. [PMID: 26936925 DOI: 10.1534/genetics.116.188037] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 02/21/2016] [Indexed: 11/18/2022] Open
Abstract
In the yeast Saccharomyces cerevisiae, beneficial mutations selected during sulfate-limited growth are typically amplifications of the SUL1 gene, which encodes the high-affinity sulfate transporter, resulting in fitness increases of >35% . Cis-regulatory mutations have not been observed at this locus; however, it is not clear whether this absence is due to a low mutation rate such that these mutations do not arise, or they arise but have limited fitness effects relative to those of amplification. To address this question directly, we assayed the fitness effects of nearly all possible point mutations in a 493-base segment of the gene's promoter through mutagenesis and selection. While most mutations were either neutral or detrimental during sulfate-limited growth, eight mutations increased fitness >5% and as much as 9.4%. Combinations of these beneficial mutations increased fitness only up to 11%. Thus, in the case of SUL1, promoter mutations could not induce a fitness increase similar to that of gene amplification. Using these data, we identified functionally important regions of the SUL1 promoter and analyzed three sites that correspond to potential binding sites for the transcription factors Met32 and Cbf1 Mutations that create new Met32- or Cbf1-binding sites also increased fitness. Some mutations in the untranslated region of the SUL1 transcript decreased fitness, likely due to the formation of inhibitory upstream open reading frames. Our methodology-saturation mutagenesis, chemostat selection, and DNA sequencing to track variants-should be a broadly applicable approach.
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20
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Schwabe A, Bruggeman FJ. Single yeast cells vary in transcription activity not in delay time after a metabolic shift. Nat Commun 2014; 5:4798. [DOI: 10.1038/ncomms5798] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 07/25/2014] [Indexed: 11/09/2022] Open
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21
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DeMille D, Bikman BT, Mathis AD, Prince JT, Mackay JT, Sowa SW, Hall TD, Grose JH. A comprehensive protein-protein interactome for yeast PAS kinase 1 reveals direct inhibition of respiration through the phosphorylation of Cbf1. Mol Biol Cell 2014; 25:2199-215. [PMID: 24850888 PMCID: PMC4091833 DOI: 10.1091/mbc.e13-10-0631] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
PAS kinase is a conserved sensory protein kinase required for glucose homeostasis. The interactome for yeast PAS kinase 1 (Psk1) is identified, revealing 93 binding partners. Evidence is provided for in vivo phosphorylation of Cbf1 and subsequent inhibition of respiration, supporting a role for Psk1 in partitioning glucose for cell growth. Per-Arnt-Sim (PAS) kinase is a sensory protein kinase required for glucose homeostasis in yeast, mice, and humans, yet little is known about the molecular mechanisms of its function. Using both yeast two-hybrid and copurification approaches, we identified the protein–protein interactome for yeast PAS kinase 1 (Psk1), revealing 93 novel putative protein binding partners. Several of the Psk1 binding partners expand the role of PAS kinase in glucose homeostasis, including new pathways involved in mitochondrial metabolism. In addition, the interactome suggests novel roles for PAS kinase in cell growth (gene/protein expression, replication/cell division, and protein modification and degradation), vacuole function, and stress tolerance. In vitro kinase studies using a subset of 25 of these binding partners identified Mot3, Zds1, Utr1, and Cbf1 as substrates. Further evidence is provided for the in vivo phosphorylation of Cbf1 at T211/T212 and for the subsequent inhibition of respiration. This respiratory role of PAS kinase is consistent with the reported hypermetabolism of PAS kinase–deficient mice, identifying a possible molecular mechanism and solidifying the evolutionary importance of PAS kinase in the regulation of glucose homeostasis.
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Affiliation(s)
- Desiree DeMille
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT 84602
| | - Benjamin T Bikman
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT 84602
| | - Andrew D Mathis
- Department of Chemistry, Brigham Young University, Provo, UT 84602
| | - John T Prince
- Department of Chemistry, Brigham Young University, Provo, UT 84602
| | - Jordan T Mackay
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT 84602
| | - Steven W Sowa
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT 84602
| | - Tacie D Hall
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT 84602
| | - Julianne H Grose
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT 84602
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22
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Yamamoto S, De D, Hidaka K, Kim KK, Endo M, Sugiyama H. Single molecule visualization and characterization of Sox2-Pax6 complex formation on a regulatory DNA element using a DNA origami frame. NANO LETTERS 2014; 14:2286-2292. [PMID: 24660747 DOI: 10.1021/nl4044949] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We report the use of atomic force microscopy (AFM) to study Sox2-Pax6 complex formation on the regulatory DNA element at a single molecule level. Using an origami DNA scaffold containing two DNA strands with different levels of tensile force, we confirmed that DNA bending is necessary for Sox2 binding. We also demonstrated that two transcription factors bind cooperatively by observing the increased occupancy of Sox2-Pax6 on the DNA element compared to that of Sox2 alone.
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Affiliation(s)
- Seigi Yamamoto
- Department of Chemistry, Graduate School of Science, Kyoto University , Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan
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23
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Treu L, Campanaro S, Nadai C, Toniolo C, Nardi T, Giacomini A, Valle G, Blondin B, Corich V. Oxidative stress response and nitrogen utilization are strongly variable in Saccharomyces cerevisiae wine strains with different fermentation performances. Appl Microbiol Biotechnol 2014; 98:4119-35. [DOI: 10.1007/s00253-014-5679-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Revised: 03/07/2014] [Accepted: 03/09/2014] [Indexed: 11/28/2022]
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24
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Abstract
The term “transcriptional network” refers to the mechanism(s) that underlies coordinated expression of genes, typically involving transcription factors (TFs) binding to the promoters of multiple genes, and individual genes controlled by multiple TFs. A multitude of studies in the last two decades have aimed to map and characterize transcriptional networks in the yeast Saccharomyces cerevisiae. We review the methodologies and accomplishments of these studies, as well as challenges we now face. For most yeast TFs, data have been collected on their sequence preferences, in vivo promoter occupancy, and gene expression profiles in deletion mutants. These systematic studies have led to the identification of new regulators of numerous cellular functions and shed light on the overall organization of yeast gene regulation. However, many yeast TFs appear to be inactive under standard laboratory growth conditions, and many of the available data were collected using techniques that have since been improved. Perhaps as a consequence, comprehensive and accurate mapping among TF sequence preferences, promoter binding, and gene expression remains an open challenge. We propose that the time is ripe for renewed systematic efforts toward a complete mapping of yeast transcriptional regulatory mechanisms.
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25
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The response to inositol: regulation of glycerolipid metabolism and stress response signaling in yeast. Chem Phys Lipids 2014; 180:23-43. [PMID: 24418527 DOI: 10.1016/j.chemphyslip.2013.12.013] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Accepted: 12/26/2013] [Indexed: 12/13/2022]
Abstract
This article focuses on discoveries of the mechanisms governing the regulation of glycerolipid metabolism and stress response signaling in response to the phospholipid precursor, inositol. The regulation of glycerolipid lipid metabolism in yeast in response to inositol is highly complex, but increasingly well understood, and the roles of individual lipids in stress response are also increasingly well characterized. Discoveries that have emerged over several decades of genetic, molecular and biochemical analyses of metabolic, regulatory and signaling responses of yeast cells, both mutant and wild type, to the availability of the phospholipid precursor, inositol are discussed.
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26
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Roy S, Lagree S, Hou Z, Thomson JA, Stewart R, Gasch AP. Integrated module and gene-specific regulatory inference implicates upstream signaling networks. PLoS Comput Biol 2013; 9:e1003252. [PMID: 24146602 PMCID: PMC3798279 DOI: 10.1371/journal.pcbi.1003252] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 08/17/2013] [Indexed: 11/19/2022] Open
Abstract
Regulatory networks that control gene expression are important in diverse biological contexts including stress response and development. Each gene's regulatory program is determined by module-level regulation (e.g. co-regulation via the same signaling system), as well as gene-specific determinants that can fine-tune expression. We present a novel approach, Modular regulatory network learning with per gene information (MERLIN), that infers regulatory programs for individual genes while probabilistically constraining these programs to reveal module-level organization of regulatory networks. Using edge-, regulator- and module-based comparisons of simulated networks of known ground truth, we find MERLIN reconstructs regulatory programs of individual genes as well or better than existing approaches of network reconstruction, while additionally identifying modular organization of the regulatory networks. We use MERLIN to dissect global transcriptional behavior in two biological contexts: yeast stress response and human embryonic stem cell differentiation. Regulatory modules inferred by MERLIN capture co-regulatory relationships between signaling proteins and downstream transcription factors thereby revealing the upstream signaling systems controlling transcriptional responses. The inferred networks are enriched for regulators with genetic or physical interactions, supporting the inference, and identify modules of functionally related genes bound by the same transcriptional regulators. Our method combines the strengths of per-gene and per-module methods to reveal new insights into transcriptional regulation in stress and development.
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Affiliation(s)
- Sushmita Roy
- Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Wisconsin Institute for Discovery, Madison, Wisconsin, United States of America
- * E-mail:
| | - Stephen Lagree
- Department of Computer Science, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Zhonggang Hou
- Morgridge Institute for Research, Madison, Wisconsin, United States of America
| | - James A. Thomson
- Morgridge Institute for Research, Madison, Wisconsin, United States of America
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Department of Molecular, Cellular, and Developmental Biology, University of California Santa Barbara, Santa Barbara, California, United States of America
| | - Ron Stewart
- Morgridge Institute for Research, Madison, Wisconsin, United States of America
| | - Audrey P. Gasch
- Department of Genetics, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
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27
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Bonhomme J, d’Enfert C. Candida albicans biofilms: building a heterogeneous, drug-tolerant environment. Curr Opin Microbiol 2013; 16:398-403. [DOI: 10.1016/j.mib.2013.03.007] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 03/11/2013] [Indexed: 01/10/2023]
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28
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McIsaac RS, Oakes BL, Wang X, Dummit KA, Botstein D, Noyes MB. Synthetic gene expression perturbation systems with rapid, tunable, single-gene specificity in yeast. Nucleic Acids Res 2012; 41:e57. [PMID: 23275543 PMCID: PMC3575806 DOI: 10.1093/nar/gks1313] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
A general method for the dynamic control of single gene expression in eukaryotes, with no off-target effects, is a long-sought tool for molecular and systems biologists. We engineered two artificial transcription factors (ATFs) that contain Cys2His2 zinc-finger DNA-binding domains of either the mouse transcription factor Zif268 (9 bp of specificity) or a rationally designed array of four zinc fingers (12 bp of specificity). These domains were expressed as fusions to the human estrogen receptor and VP16 activation domain. The ATFs can rapidly induce a single gene driven by a synthetic promoter in response to introduction of an otherwise inert hormone with no detectable off-target effects. In the absence of inducer, the synthetic promoter is inactive and the regulated gene product is not detected. Following addition of inducer, transcripts are induced >50-fold within 15 min. We present a quantitative characterization of these ATFs and provide constructs for making their implementation straightforward. These new tools allow for the elucidation of regulatory network elements dynamically, which we demonstrate with a major metabolic regulator, Gcn4p.
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Affiliation(s)
- R Scott McIsaac
- The Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA.
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29
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Linder T. Genomics of alternative sulfur utilization in ascomycetous yeasts. MICROBIOLOGY-SGM 2012; 158:2585-2597. [PMID: 22790398 DOI: 10.1099/mic.0.060285-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Thirteen ascomycetous yeast strains with sequenced genomes were assayed for their ability to grow on chemically defined medium with 16 different sulfur compounds as the only significant source of sulfur. These compounds included sulfoxides, sulfones, sulfonates, sulfamates and sulfate esters. Broad utilization of alternative sulfur sources was observed in Komagataella pastoris (syn. Pichia pastoris), Lodderomyces elongisporus, Millerozyma farinosa (syn. Pichia sorbitophila), Pachysolen tannophilus, Scheffersomyces stipitis (syn. Pichia stipitis), Spathaspora passalidarum, Yamadazyma tenuis (syn. Candida tenuis) and Yarrowia lipolytica. Kluyveromyces lactis, Saccharomyces cerevisiae and Zygosaccharomyces rouxii were mainly able to utilize sulfonates and sulfate esters, while Lachancea thermotolerans and Schizosaccharomyces pombe were limited to aromatic sulfate esters. Genome analysis identified several candidate genes with bacterial homologues that had been previously shown to be involved in the utilization of alternative sulfur sources. Analysis of candidate gene promoter sequences revealed a significant overrepresentation of DNA motifs that have been shown to regulate sulfur metabolism in Sacc. cerevisiae.
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Affiliation(s)
- Tomas Linder
- Department of Microbiology, Swedish University of Agricultural Sciences, Box 7050, SE-750 07, Uppsala, Sweden
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30
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McIsaac RS, Petti AA, Bussemaker HJ, Botstein D. Perturbation-based analysis and modeling of combinatorial regulation in the yeast sulfur assimilation pathway. Mol Biol Cell 2012; 23:2993-3007. [PMID: 22696683 PMCID: PMC3408425 DOI: 10.1091/mbc.e12-03-0232] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Here we establish the utility of a recently described perturbative method to study complex regulatory circuits in vivo. By combining rapid modulation of single TFs under physiological conditions with genome-wide expression analysis, we elucidate several novel regulatory features within the pathways of sulfur assimilation and beyond. In yeast, the pathways of sulfur assimilation are combinatorially controlled by five transcriptional regulators (three DNA-binding proteins [Met31p, Met32p, and Cbf1p], an activator [Met4p], and a cofactor [Met28p]) and a ubiquitin ligase subunit (Met30p). This regulatory system exerts combinatorial control not only over sulfur assimilation and methionine biosynthesis, but also on many other physiological functions in the cell. Recently we characterized a gene induction system that, upon the addition of an inducer, results in near-immediate transcription of a gene of interest under physiological conditions. We used this to perturb levels of single transcription factors during steady-state growth in chemostats, which facilitated distinction of direct from indirect effects of individual factors dynamically through quantification of the subsequent changes in genome-wide patterns of gene expression. We were able to show directly that Cbf1p acts sometimes as a repressor and sometimes as an activator. We also found circumstances in which Met31p/Met32p function as repressors, as well as those in which they function as activators. We elucidated and numerically modeled feedback relationships among the regulators, notably feedforward regulation of Met32p (but not Met31p) by Met4p that generates dynamic differences in abundance that can account for the differences in function of these two proteins despite their identical binding sites.
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Affiliation(s)
- R Scott McIsaac
- The Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA.
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