1
|
Gilea AI, Magistrati M, Notaroberto I, Tiso N, Dallabona C, Baruffini E. The Saccharomyces cerevisiae mitochondrial DNA polymerase and its contribution to the knowledge about human POLG-related disorders. IUBMB Life 2023; 75:983-1002. [PMID: 37470284 DOI: 10.1002/iub.2770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 07/05/2023] [Indexed: 07/21/2023]
Abstract
Most eukaryotes possess a mitochondrial genome, called mtDNA. In animals and fungi, the replication of mtDNA is entrusted by the DNA polymerase γ, or Pol γ. The yeast Pol γ is composed only of a catalytic subunit encoded by MIP1. In humans, Pol γ is a heterotrimer composed of a catalytic subunit homolog to Mip1, encoded by POLG, and two accessory subunits. In the last 25 years, more than 300 pathological mutations in POLG have been identified as the cause of several mitochondrial diseases, called POLG-related disorders, which are characterized by multiple mtDNA deletions and/or depletion in affected tissues. In this review, at first, we summarize the biochemical properties of yeast Mip1, and how mutations, especially those introduced recently in the N-terminal and C-terminal regions of the enzyme, affect the in vitro activity of the enzyme and the in vivo phenotype connected to the mtDNA stability and to the mtDNA extended and point mutability. Then, we focus on the use of yeast harboring Mip1 mutations equivalent to the human ones to confirm their pathogenicity, identify the phenotypic defects caused by these mutations, and find both mechanisms and molecular compounds able to rescue the detrimental phenotype. A closing chapter will be dedicated to other polymerases found in yeast mitochondria, namely Pol ζ, Rev1 and Pol η, and to their genetic interactions with Mip1 necessary to maintain mtDNA stability and to avoid the accumulation of spontaneous or induced point mutations.
Collapse
Affiliation(s)
- Alexandru Ionut Gilea
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Martina Magistrati
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Ilenia Notaroberto
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Natascia Tiso
- Department of Biology, University of Padova, Padova, Italy
| | - Cristina Dallabona
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Enrico Baruffini
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| |
Collapse
|
2
|
Meydan S, Barros GC, Simões V, Harley L, Cizubu BK, Guydosh NR, Silva GM. The ubiquitin conjugase Rad6 mediates ribosome pausing during oxidative stress. Cell Rep 2023; 42:113359. [PMID: 37917585 PMCID: PMC10755677 DOI: 10.1016/j.celrep.2023.113359] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 07/26/2023] [Accepted: 10/13/2023] [Indexed: 11/04/2023] Open
Abstract
Oxidative stress causes K63-linked ubiquitination of ribosomes by the E2 ubiquitin conjugase Rad6. How Rad6-mediated ubiquitination of ribosomes affects translation, however, is unclear. We therefore perform Ribo-seq and Disome-seq in Saccharomyces cerevisiae and show that oxidative stress causes ribosome pausing at specific amino acid motifs, which also leads to ribosome collisions. However, these redox-pausing signatures are lost in the absence of Rad6 and do not depend on the ribosome-associated quality control (RQC) pathway. We also show that Rad6 is needed to inhibit overall translation in response to oxidative stress and that its deletion leads to increased expression of antioxidant genes. Finally, we observe that the lack of Rad6 leads to changes during translation that affect activation of the integrated stress response (ISR) pathway. Our results provide a high-resolution picture of the gene expression changes during oxidative stress and unravel an additional stress response pathway affecting translation elongation.
Collapse
Affiliation(s)
- Sezen Meydan
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA; Postdoctoral Research Associate Training Fellowship, National Institute of General Medical Sciences, National Institutes of Health, Bethesda, MD 20982, USA
| | | | - Vanessa Simões
- Department of Biology, Duke University, Durham, NC 27708, USA
| | - Lana Harley
- Department of Biology, Duke University, Durham, NC 27708, USA
| | | | - Nicholas R Guydosh
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Gustavo M Silva
- Department of Biology, Duke University, Durham, NC 27708, USA.
| |
Collapse
|
3
|
Son YJ, Jeon M, Moon HY, Kang J, Jeong DM, Lee DW, Kim JH, Lim JY, Seo J, Jin J, Bahn Y, Eyun S, Kang HA. Integrated genomics and phenotype microarray analysis of Saccharomyces cerevisiae industrial strains for rice wine fermentation and recombinant protein production. Microb Biotechnol 2023; 16:2161-2180. [PMID: 37837246 PMCID: PMC10616653 DOI: 10.1111/1751-7915.14354] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Revised: 08/28/2023] [Accepted: 09/24/2023] [Indexed: 10/15/2023] Open
Abstract
The industrial potential of Saccharomyces cerevisiae has extended beyond its traditional use in fermentation to various applications, including recombinant protein production. Herein, comparative genomics was performed with three industrial S. cerevisiae strains and revealed a heterozygous diploid genome for the 98-5 and KSD-YC strains (exploited for rice wine fermentation) and a haploid genome for strain Y2805 (used for recombinant protein production). Phylogenomic analysis indicated that Y2805 was closely associated with the reference strain S288C, whereas KSD-YC and 98-5 were grouped with Asian and European wine strains, respectively. Particularly, a single nucleotide polymorphism (SNP) in FDC1, involved in the biosynthesis of 4-vinylguaiacol (4-VG, a phenolic compound with a clove-like aroma), was found in KSD-YC, consistent with its lack of 4-VG production. Phenotype microarray (PM) analysis showed that KSD-YC and 98-5 displayed broader substrate utilization than S288C and Y2805. The SNPs detected by genome comparison were mapped to the genes responsible for the observed phenotypic differences. In addition, detailed information on the structural organization of Y2805 selection markers was validated by Sanger sequencing. Integrated genomics and PM analysis elucidated the evolutionary history and genetic diversity of industrial S. cerevisiae strains, providing a platform to improve fermentation processes and genetic manipulation.
Collapse
Affiliation(s)
- Ye Ji Son
- Department of Life ScienceChung‐Ang UniversitySeoulKorea
| | - Min‐Seung Jeon
- Department of Life ScienceChung‐Ang UniversitySeoulKorea
| | - Hye Yun Moon
- Department of Life ScienceChung‐Ang UniversitySeoulKorea
| | - Jiwon Kang
- Department of Life ScienceChung‐Ang UniversitySeoulKorea
| | - Da Min Jeong
- Department of Life ScienceChung‐Ang UniversitySeoulKorea
| | - Dong Wook Lee
- Department of Life ScienceChung‐Ang UniversitySeoulKorea
| | - Jae Ho Kim
- Korea Food Research InstituteWanju‐GunJeollabukdoKorea
| | - Jae Yun Lim
- School of Systems Biomedical ScienceSoongsil UniversitySeoulKorea
| | - Jeong‐Ah Seo
- School of Systems Biomedical ScienceSoongsil UniversitySeoulKorea
| | - Jae‐Hyung Jin
- Department of BiotechnologyYonsei UniversitySeoulKorea
| | - Yong‐Sun Bahn
- Department of BiotechnologyYonsei UniversitySeoulKorea
| | - Seong‐il Eyun
- Department of Life ScienceChung‐Ang UniversitySeoulKorea
| | - Hyun Ah Kang
- Department of Life ScienceChung‐Ang UniversitySeoulKorea
| |
Collapse
|
4
|
Robinson D, Vanacloig-Pedros E, Cai R, Place M, Hose J, Gasch AP. Gene-by-environment interactions influence the fitness cost of gene copy-number variation in yeast. G3 (BETHESDA, MD.) 2023; 13:jkad159. [PMID: 37481264 PMCID: PMC10542507 DOI: 10.1093/g3journal/jkad159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 05/11/2023] [Accepted: 07/12/2023] [Indexed: 07/24/2023]
Abstract
Variation in gene copy number can alter gene expression and influence downstream phenotypes; thus copy-number variation provides a route for rapid evolution if the benefits outweigh the cost. We recently showed that genetic background significantly influences how yeast cells respond to gene overexpression, revealing that the fitness costs of copy-number variation can vary substantially with genetic background in a common-garden environment. But the interplay between copy-number variation tolerance and environment remains unexplored on a genomic scale. Here, we measured the tolerance to gene overexpression in four genetically distinct Saccharomyces cerevisiae strains grown under sodium chloride stress. Overexpressed genes that are commonly deleterious during sodium chloride stress recapitulated those commonly deleterious under standard conditions. However, sodium chloride stress uncovered novel differences in strain responses to gene overexpression. West African strain NCYC3290 and North American oak isolate YPS128 are more sensitive to sodium chloride stress than vineyard BC187 and laboratory strain BY4743. Consistently, NCYC3290 and YPS128 showed the greatest sensitivities to overexpression of specific genes. Although most genes were deleterious, hundreds were beneficial when overexpressed-remarkably, most of these effects were strain specific. Few beneficial genes were shared between the sodium chloride-sensitive isolates, implicating mechanistic differences behind their sodium chloride sensitivity. Transcriptomic analysis suggested underlying vulnerabilities and tolerances across strains, and pointed to natural copy-number variation of a sodium export pump that likely contributes to strain-specific responses to overexpression of other genes. Our results reveal extensive strain-by-environment interactions in the response to gene copy-number variation, raising important implications for the accessibility of copy-number variation-dependent evolutionary routes under times of stress.
Collapse
Affiliation(s)
- DeElegant Robinson
- Center for Genomic Science Innovation, University of Wisconsin-Madison, Madison, WI 53704, USA
| | - Elena Vanacloig-Pedros
- Center for Genomic Science Innovation, University of Wisconsin-Madison, Madison, WI 53704, USA
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI 53704, USA
| | - Ruoyi Cai
- Center for Genomic Science Innovation, University of Wisconsin-Madison, Madison, WI 53704, USA
| | - Michael Place
- Center for Genomic Science Innovation, University of Wisconsin-Madison, Madison, WI 53704, USA
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI 53704, USA
| | - James Hose
- Center for Genomic Science Innovation, University of Wisconsin-Madison, Madison, WI 53704, USA
| | - Audrey P Gasch
- Center for Genomic Science Innovation, University of Wisconsin-Madison, Madison, WI 53704, USA
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI 53704, USA
- Department of Medical Genetics, University of Wisconsin-Madison, Madison, WI 53704, USA
| |
Collapse
|
5
|
Robinson D, Vanacloig-Pedros E, Cai R, Place M, Hose J, Gasch AP. Gene-by-environment interactions influence the fitness cost of gene copy-number variation in yeast. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.11.540375. [PMID: 37503218 PMCID: PMC10369901 DOI: 10.1101/2023.05.11.540375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Variation in gene copy number can alter gene expression and influence downstream phenotypes; thus copy-number variation (CNV) provides a route for rapid evolution if the benefits outweigh the cost. We recently showed that genetic background significantly influences how yeast cells respond to gene over-expression (OE), revealing that the fitness costs of CNV can vary substantially with genetic background in a common-garden environment. But the interplay between CNV tolerance and environment remains unexplored on a genomic scale. Here we measured the tolerance to gene OE in four genetically distinct Saccharomyces cerevisiae strains grown under sodium chloride (NaCl) stress. OE genes that are commonly deleterious during NaCl stress recapitulated those commonly deleterious under standard conditions. However, NaCl stress uncovered novel differences in strain responses to gene OE. West African strain NCYC3290 and North American oak isolate YPS128 are more sensitive to NaCl stress than vineyard BC187 and laboratory strain BY4743. Consistently, NCYC3290 and YPS128 showed the greatest sensitivities to gene OE. Although most genes were deleterious, hundreds were beneficial when overexpressed - remarkably, most of these effects were strain specific. Few beneficial genes were shared between the NaCl-sensitive isolates, implicating mechanistic differences behind their NaCl sensitivity. Transcriptomic analysis suggested underlying vulnerabilities and tolerances across strains, and pointed to natural CNV of a sodium export pump that likely contributes to strain-specific responses to OE of other genes. Our results reveal extensive strain-by-environment interaction in the response to gene CNV, raising important implications for the accessibility of CNV-dependent evolutionary routes under times of stress.
Collapse
Affiliation(s)
- DeElegant Robinson
- Center for Genomic Science Innovation, University of Wisconsin-Madison, Madison WI 53704
| | - Elena Vanacloig-Pedros
- Center for Genomic Science Innovation, University of Wisconsin-Madison, Madison WI 53704
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison WI 53704
| | - Ruoyi Cai
- Center for Genomic Science Innovation, University of Wisconsin-Madison, Madison WI 53704
| | - Michael Place
- Center for Genomic Science Innovation, University of Wisconsin-Madison, Madison WI 53704
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison WI 53704
| | - James Hose
- Center for Genomic Science Innovation, University of Wisconsin-Madison, Madison WI 53704
| | - Audrey P Gasch
- Center for Genomic Science Innovation, University of Wisconsin-Madison, Madison WI 53704
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison WI 53704
- Department of Medical Genetics, University of Wisconsin-Madison, Madison WI 53704
| |
Collapse
|
6
|
Hutchinson KM, Hunn JC, Reines D. Nab3 nuclear granule accumulation is driven by respiratory capacity. Curr Genet 2022; 68:581-591. [PMID: 35922525 PMCID: PMC9887517 DOI: 10.1007/s00294-022-01248-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 07/18/2022] [Accepted: 07/20/2022] [Indexed: 02/02/2023]
Abstract
Numerous biological processes involve proteins capable of transiently assembling into subcellular compartments necessary for cellular functions. One process is the RNA polymerase II transcription cycle which involves initiation, elongation, co-transcriptional modification of nascent RNA, and termination. The essential yeast transcription termination factor Nab3 is required for termination of small non-coding RNAs and accumulates into a compact nuclear granule upon glucose removal. Nab3 nuclear granule accumulation varies in penetrance across yeast strains and a higher Nab3 granule accumulation phenotype is associated with petite strains, suggesting a possible ATP-dependent mechanism for granule disassembly. Here, we demonstrate the uncoupling of mitochondrial oxidative phosphorylation by drug treatment or deletions of nuclear-encoded ATP synthase subunit genes were sufficient to increase Nab3 granule accumulation and led to an inability to proliferate during prolonged glucose deprivation, which requires respiration. Additionally, by enriching for respiration competent cells from a petite-prone strain, we generated a low granule-accumulating strain from a relatively high one, providing another link between respiratory competency and Nab3 granules. Consistent with the resulting idea that ATP is involved in granule accumulation, the addition of extracellular ATP to semi-permeabilized cells was sufficient to reduce Nab3 granule accumulation. Deleting the SKY1 gene, which encodes a kinase that phosphorylates nuclear SR repeat-containing proteins and is involved in efficient stress granule disassembly, also resulted in increased granule accumulation. This observation implicates Sky1 in Nab3 granule biogenesis. Taken together, these findings suggest there is normally an equilibrium between termination factor granule assembly and disassembly mediated by ATP-requiring nuclear machinery.
Collapse
Affiliation(s)
| | - Jeremy C Hunn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, USA
| | - Daniel Reines
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, USA.
| |
Collapse
|
7
|
Variable penetrance of Nab3 granule accumulation quantified by a new tool for high-throughput single-cell granule analysis. Curr Genet 2022; 68:467-480. [PMID: 35301575 DOI: 10.1007/s00294-022-01234-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 02/16/2022] [Accepted: 03/02/2022] [Indexed: 12/12/2022]
Abstract
Reorganization of cellular proteins into subcellular compartments, such as the concentration of RNA-binding proteins into cytoplasmic stress granules and P-bodies, is a well-recognized, widely studied physiological process currently under intense investigation. One example of this is the induction of the yeast Nab3 transcription termination factor to rearrange from its pan-nucleoplasmic distribution to a granule at the nuclear periphery in response to nutrient limitation. Recent work in many cell types has shown that protein condensation in the nucleus is functionally important for transcription initiation, RNA processing, and termination. However, little is known about how subnuclear compartments form. Here, we have quantitatively analyzed this dynamic process in living yeast using a high-throughput computational tool and fluorescence microscopy. This analysis revealed that Nab3 granule accumulation varies in penetrance across yeast strains. A concentrated single granule is formed from at least a quarter of the nuclear Nab3 drawn from the rest of the nucleus. Levels of granule accumulation were inversely correlated with a growth defect in the absence of glucose. Importantly, the basis for some of the variation in penetrance was attributable to a defect in mitochondrial function. This publicly available computational tool provides a rigorous, reproducible, and unbiased examination of Nab3 granule accumulation that should be widely applicable to a variety of fluorescent images. Thousands of live cells can be readily examined enabling rigorous statistical verification of significance. With it, we describe a new feature of inducible subnuclear compartment formation for RNA-binding transcription factors and an important determinant of granule biogenesis.
Collapse
|
8
|
Kokina A, Tanilas K, Ozolina Z, Pleiko K, Shvirksts K, Vamza I, Liepins J. Purine Auxotrophic Starvation Evokes Phenotype Similar to Stationary Phase Cells in Budding Yeast. J Fungi (Basel) 2021; 8:29. [PMID: 35049969 PMCID: PMC8780165 DOI: 10.3390/jof8010029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 12/20/2021] [Accepted: 12/24/2021] [Indexed: 11/25/2022] Open
Abstract
Purine auxotrophy is an abundant trait among eukaryotic parasites and a typical marker for many budding yeast strains. Supplementation with an additional purine source (such as adenine) is necessary to cultivate these strains. If not supplied in adequate amounts, purine starvation sets in. We explored purine starvation effects in a model organism, a budding yeast Saccharomyces cerevisiae ade8 knockout, at the level of cellular morphology, central carbon metabolism, and global transcriptome. We observed that purine-starved cells stopped their cycle in G1/G0 state and accumulated trehalose, and the intracellular concentration of AXP decreased, but adenylate charge remained stable. Cells became tolerant to severe environmental stresses. Intracellular RNA concentration decreased, and massive downregulation of ribosomal biosynthesis genes occurred. We proved that the expression of new proteins during purine starvation is critical for cells to attain stress tolerance phenotype Msn2/4p targets are upregulated in purine-starved cells when compared to cells cultivated in purine-rich media. The overall transcriptomic response to purine starvation resembles that of stationary phase cells. Our results demonstrate that the induction of a strong stress resistance phenotype in budding yeast can be caused not only by natural starvation, but also starvation for metabolic intermediates, such as purines.
Collapse
Affiliation(s)
- Agnese Kokina
- Institute of Microbiology and Biotechnology, University of Latvia, Jelgavas 1, LV-1004 Riga, Latvia; (Z.O.); (K.S.); (I.V.); (J.L.)
| | - Kristel Tanilas
- Center of Food and Fermentation Technologies, Akadeemia Tee 15A, 12618 Tallinn, Estonia;
| | - Zane Ozolina
- Institute of Microbiology and Biotechnology, University of Latvia, Jelgavas 1, LV-1004 Riga, Latvia; (Z.O.); (K.S.); (I.V.); (J.L.)
| | - Karlis Pleiko
- Faculty of Medicine, University of Latvia, Jelgavas 3, LV-1004 Riga, Latvia;
- Laboratory of Precision and Nanomedicine, Institute of Biomedicine and Translational Medicine, University of Tartu, 50411 Tartu, Estonia
| | - Karlis Shvirksts
- Institute of Microbiology and Biotechnology, University of Latvia, Jelgavas 1, LV-1004 Riga, Latvia; (Z.O.); (K.S.); (I.V.); (J.L.)
| | - Ilze Vamza
- Institute of Microbiology and Biotechnology, University of Latvia, Jelgavas 1, LV-1004 Riga, Latvia; (Z.O.); (K.S.); (I.V.); (J.L.)
| | - Janis Liepins
- Institute of Microbiology and Biotechnology, University of Latvia, Jelgavas 1, LV-1004 Riga, Latvia; (Z.O.); (K.S.); (I.V.); (J.L.)
| |
Collapse
|
9
|
Sénécaut N, Alves G, Weisser H, Lignières L, Terrier S, Yang-Crosson L, Poulain P, Lelandais G, Yu YK, Camadro JM. Novel Insights into Quantitative Proteomics from an Innovative Bottom-Up Simple Light Isotope Metabolic (bSLIM) Labeling Data Processing Strategy. J Proteome Res 2021; 20:1476-1487. [PMID: 33573382 PMCID: PMC8459934 DOI: 10.1021/acs.jproteome.0c00478] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Simple light isotope metabolic labeling (SLIM labeling) is an innovative method to quantify variations in the proteome based on an original in vivo labeling strategy. Heterotrophic cells grown in U-[12C] as the sole source of carbon synthesize U-[12C]-amino acids, which are incorporated into proteins, giving rise to U-[12C]-proteins. This results in a large increase in the intensity of the monoisotope ion of peptides and proteins, thus allowing higher identification scores and protein sequence coverage in mass spectrometry experiments. This method, initially developed for signal processing and quantification of the incorporation rate of 12C into peptides, was based on a multistep process that was difficult to implement for many laboratories. To overcome these limitations, we developed a new theoretical background to analyze bottom-up proteomics data using SLIM-labeling (bSLIM) and established simple procedures based on open-source software, using dedicated OpenMS modules, and embedded R scripts to process the bSLIM experimental data. These new tools allow computation of both the 12C abundance in peptides to follow the kinetics of protein labeling and the molar fraction of unlabeled and 12C-labeled peptides in multiplexing experiments to determine the relative abundance of proteins extracted under different biological conditions. They also make it possible to consider incomplete 12C labeling, such as that observed in cells with nutritional requirements for nonlabeled amino acids. These tools were validated on an experimental dataset produced using various yeast strains of Saccharomyces cerevisiae and growth conditions. The workflows are built on the implementation of appropriate calculation modules in a KNIME working environment. These new integrated tools provide a convenient framework for the wider use of the SLIM-labeling strategy.
Collapse
Affiliation(s)
- Nicolas Sénécaut
- ≪ Mitochondria, Metals, and Oxidative Stress ≫ Group, Université de Paris-CNRS, Institut Jacques Monod, 75013 Paris, France
| | - Gelio Alves
- National Center for Biotechnology Information, NLM, NIH, Bethesda, Maryland 20894, United States
| | | | - Laurent Lignières
- ProteoSeine@IJM, Université de Paris-CNRS, Institut Jacques Monod, 75013 Paris, France
| | - Samuel Terrier
- ProteoSeine@IJM, Université de Paris-CNRS, Institut Jacques Monod, 75013 Paris, France
| | - Lilian Yang-Crosson
- ≪ Mitochondria, Metals, and Oxidative Stress ≫ Group, Université de Paris-CNRS, Institut Jacques Monod, 75013 Paris, France
| | - Pierre Poulain
- ≪ Mitochondria, Metals, and Oxidative Stress ≫ Group, Université de Paris-CNRS, Institut Jacques Monod, 75013 Paris, France
| | - Gaëlle Lelandais
- Institut de Biologie Intégrative de la Cellule, 91190 Orsay, France
| | - Yi-Kuo Yu
- National Center for Biotechnology Information, NLM, NIH, Bethesda, Maryland 20894, United States
| | - Jean-Michel Camadro
- ≪ Mitochondria, Metals, and Oxidative Stress ≫ Group, Université de Paris-CNRS, Institut Jacques Monod, 75013 Paris, France
- ProteoSeine@IJM, Université de Paris-CNRS, Institut Jacques Monod, 75013 Paris, France
| |
Collapse
|
10
|
Young MJ, Imperial RJ, Lakhi S, Court DA. A non-radioactive DNA synthesis assay demonstrates that elements of the Sigma 1278b Mip1 mitochondrial DNA polymerase domain and C-terminal extension facilitate robust enzyme activity. Yeast 2021; 38:262-275. [PMID: 33270277 DOI: 10.1002/yea.3541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 11/20/2020] [Accepted: 11/26/2020] [Indexed: 11/06/2022] Open
Abstract
The yeast DNA polymerase gamma, Mip1, is a useful tool to investigate the impact of orthologous human disease variants on mitochondrial DNA (mtDNA) replication. However, Mip1 is characterized by a C-terminal extension (CTE) that is not found on orthologous metazoan DNA polymerases, and the CTE is required for robust enzymatic activity. Two MIP1 alleles exist in standard yeast strains, encoding Mip1[S] or Mip1[Σ]. Mip1[S] is associated with reduced mtDNA stability and increased error rates in vivo. Although the Mip1[S] allele was initially identified in S288c, the Mip1[Σ] allele is widely present among available yeast genome sequences, suggesting that it is the wild-type (WT) allele. We developed a novel non-radioactive polymerase gamma assay to assess Mip1 functioning at its intracellular location, the mitochondrial membrane. Membrane fractions were isolated from yeast cells expressing full-length or CTE truncation variants of Mip1[S] or a chimeric Mip1[S] isoform harboring the Mip1[Σ]-specific T661 residue (cMip1 T661). Relative incorporation of digoxigenin (DIG)-11-deoxyuridine monophosphate (DIG-dUMP) by cMip1 T661 was higher than that by Mip1[S]. A cMip1 T661variant lacking 175 C-terminal residues maintained WT levels of DIG-dUMP incorporation, whereas the C-terminal variant lacking 205 residues displayed a significant decrease in incorporation. Newly synthesized DIG-labeled DNA decreased during later phases of reactions carried out at 37°C, suggesting temperature-sensitive destabilization of the polymerase domain and/or increased shuttling of the nascent DNA into the exonuclease domain. Comparative analysis of Mip1 enzyme functions using our novel assay has further demonstrated the importance of the CTE and T661 encoded by MIP1[Σ] in yeast mtDNA replication.
Collapse
Affiliation(s)
- Matthew J Young
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada.,Department of Biochemistry and Molecular Biology, School of Medicine, Southern Illinois University, Carbondale, Illinois, USA
| | - Robin J Imperial
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada.,Truman Medical Center, University of Missouri-Kansas City, Kansas City, Missouri, USA
| | - Suman Lakhi
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada.,Max Rady College of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Deborah A Court
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
| |
Collapse
|
11
|
Amino and carboxy-terminal extensions of yeast mitochondrial DNA polymerase assemble both the polymerization and exonuclease active sites. Mitochondrion 2019; 49:166-177. [PMID: 31445096 DOI: 10.1016/j.mito.2019.08.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 08/11/2019] [Accepted: 08/19/2019] [Indexed: 11/24/2022]
Abstract
Human and yeast mitochondrial DNA polymerases (DNAPs), POLG and Mip1, are related by evolution to bacteriophage DNAPs. However, mitochondrial DNAPs contain unique amino and carboxyl-terminal extensions that physically interact. Here we describe that N-terminal deletions in Mip1 polymerases abolish polymerization and decrease exonucleolytic degradation, whereas moderate C-terminal deletions reduce polymerization. Similarly, to the N-terminal deletions, an extended C-terminal deletion of 298 amino acids is deficient in nucleotide addition and exonucleolytic degradation of double and single-stranded DNA. The latter observation suggests that the physical interaction between the amino and carboxyl-terminal regions of Mip1 may be related to the spread of pathogenic POLG mutant along its primary sequence.
Collapse
|
12
|
Simpson-Lavy K, Kupiec M. Carbon Catabolite Repression in Yeast is Not Limited to Glucose. Sci Rep 2019; 9:6491. [PMID: 31019232 PMCID: PMC6482301 DOI: 10.1038/s41598-019-43032-w] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 04/12/2019] [Indexed: 01/18/2023] Open
Abstract
Cells adapt their gene expression and their metabolism in response to a changing environment. Glucose represses expression of genes involved in the catabolism of other carbon sources in a process known as (carbon) catabolite repression. However, the relationships between “poor” carbon sources is less characterized. Here we show that in addition to the well-characterized glucose (and galactose) repression of ADH2 (alcohol dehydrogenase 2, required for efficient utilization of ethanol as a carbon source), ADH2 expression is also inhibited by acetate which is produced during ethanol catabolism. Thus, repressive regulation of gene expression occurs also between “poor” carbon sources. Acetate repression of ADH2 expression is via Haa1, independently from the well-characterized mechanism of AMPK (Snf1) activation of Adr1. The response to extracellular acetate is attenuated when all three acetate transporters (Ady2, Fps1 and Jen1) are deleted, but these deletions do not affect the acetate response resulting from growth with glucose or ethanol as the carbon source. Furthermore, genetic manipulation of the ethanol catabolic pathway affects this response. Together, our results show that acetate is sensed intracellularly and that a hierarchical control of carbon sources exists even for “poor” carbon sources.
Collapse
Affiliation(s)
- Kobi Simpson-Lavy
- School of Molecular Cell Biology & Biotechnology, Tel Aviv University, Ramat Aviv, 69978, Israel
| | - Martin Kupiec
- School of Molecular Cell Biology & Biotechnology, Tel Aviv University, Ramat Aviv, 69978, Israel.
| |
Collapse
|
13
|
CDK contribution to DSB formation and recombination in fission yeast meiosis. PLoS Genet 2019; 15:e1007876. [PMID: 30640914 PMCID: PMC6331086 DOI: 10.1371/journal.pgen.1007876] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 12/04/2018] [Indexed: 12/19/2022] Open
Abstract
CDKs (cyclin-dependent kinases) associate with different cyclins to form different CDK-complexes that are fundamental for an ordered cell cycle progression, and the coordination of this progression with different aspects of the cellular physiology. During meiosis programmed DNA double-strand breaks (DSBs) initiate recombination that in addition to generating genetic variability are essential for the reductional chromosome segregation during the first meiotic division, and therefore for genome stability and viability of the gametes. However, how meiotic progression and DSB formation are coordinated, and the role CDKs have in the process, is not well understood. We have used single and double cyclin deletion mutants, and chemical inhibition of global CDK activity using the cdc2-asM17 allele, to address the requirement of CDK activity for DSB formation and recombination in fission yeast. We report that several cyclins (Cig1, Cig2, and the meiosis-specific Crs1) control DSB formation and recombination, with a major contribution of Crs1. Moreover, complementation analysis indicates specificity at least for this cyclin, suggesting that different CDK complexes might act in different pathways to promote recombination. Down-regulation of CDK activity impinges on the formation of linear elements (LinEs, protein complexes required for break formation at most DSB hotspot sites). This defect correlates with a reduction in the capability of one structural component (Rec25) to bind chromatin, suggesting a molecular mechanism by which CDK controls break formation. However, reduction in DSB formation in cyclin deletion mutants does not always correspondingly correlate with a proportional reduction in meiotic recombination (crossovers), suggesting that specific CDK complexes might also control downstream events balancing repair pathways. Therefore, our work points to CDK regulation of DSB formation as a key conserved feature in the initiation of meiotic recombination, in addition to provide a view of possible roles CDK might have in other steps of the recombination process. Meiotic division is a cell division process where a single round of DNA replication is followed by two sequential chromosome segregations, the first reductional (homologous chromosomes separate) and the second equational (sister chromatids segregate). As a consequence diploid organisms halve ploidy, producing haploid gametes that after fertilization generate a new diploid organism with a complete chromosome complement. At early stages of meiosis physical exchange between homologous chromosomes ensures the accurate following reductional segregation. Physical exchange is provided by recombination that initiates with highly-controlled self-inflicted DNA damage (DSBs, double strand breaks). We have found that the conserved CDK (cyclin-dependent kinase) activity controls DSB formation in fission yeast. Available data were uncertain about the conservation of CDK in the process, and thus our work points to a broad evolutionary conservation of this regulation. Regulation is exerted at least by controlling chromatin-binding of one structural component of linear elements, a protein complex related to the synaptonemal complex and required for high levels of DSBs. Correspondingly, depletion of CDK activity impairs formation of these structures. In addition, CDK might control homeostatic mechanisms, critical to maintain efficient levels of recombination across the genome and, therefore, high rates of genetic exchange between parental chromosomes.
Collapse
|
14
|
García-Guerrero AE, Camacho-Villasana Y, Zamudio-Ochoa A, Winge DR, Pérez-Martínez X. Cbp3 and Cbp6 are dispensable for synthesis regulation of cytochrome b in yeast mitochondria. J Biol Chem 2018; 293:5585-5599. [PMID: 29475949 DOI: 10.1074/jbc.ra117.000547] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 02/08/2018] [Indexed: 11/06/2022] Open
Abstract
Cytochrome b (Cytb) is the only mitochondrial encoded subunit from the bc1 complex. Cbp3 and Cbp6 are chaperones necessary for translation of the COB mRNA and Cytb hemylation. Here we demonstrate that their role in translation is dispensable in some laboratory strains, whereas their role in Cytb hemylation seems to be universally conserved. BY4742 yeast requires Cbp3 and Cbp6 for efficient COB mRNA translation, whereas the D273-10b strain synthesizes Cytb at wildtype levels in the absence of Cbp3 and Cbp6. Steady-state levels of Cytb are close to wildtype in mutant D273-10b cells, and Cytb forms non-functional, supercomplex-like species with cytochrome c oxidase, in which at least core 1, cytochrome c1, and Rieske iron-sulfur subunits are present. We demonstrated that Cbp3 interacts with the mitochondrial ribosome and with the COB mRNA in both BY4742 and D273-10b strains. The polymorphism(s) causing the differential function of Cbp3, Cbp6, and the assembly feedback regulation of Cytb synthesis is of nuclear origin rather than mitochondrial, and Smt1, a COB mRNA-binding protein, does not seem to be involved in the observed differential phenotype. Our results indicate that the essential role of Cbp3 and Cbp6 is to assist Cytb hemylation and demonstrate that in the absence of heme b, Cytb can form non-functional supercomplexes with cytochrome c oxidase. Our observations support that an additional protein or proteins are involved in Cytb synthesis in some yeast strains.
Collapse
Affiliation(s)
- Aldo E García-Guerrero
- From the Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito Exterior s/n Ciudad Universitaria, Coyoacán, 04510 Mexico City, Mexico and
| | - Yolanda Camacho-Villasana
- From the Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito Exterior s/n Ciudad Universitaria, Coyoacán, 04510 Mexico City, Mexico and
| | - Angélica Zamudio-Ochoa
- From the Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito Exterior s/n Ciudad Universitaria, Coyoacán, 04510 Mexico City, Mexico and
| | - Dennis R Winge
- the Department of Medicine and Biochemistry, University of Utah Health Sciences Center, Salt Lake, Utah 84132
| | - Xochitl Pérez-Martínez
- From the Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito Exterior s/n Ciudad Universitaria, Coyoacán, 04510 Mexico City, Mexico and
| |
Collapse
|
15
|
Sardi M, Paithane V, Place M, Robinson DE, Hose J, Wohlbach DJ, Gasch AP. Genome-wide association across Saccharomyces cerevisiae strains reveals substantial variation in underlying gene requirements for toxin tolerance. PLoS Genet 2018; 14:e1007217. [PMID: 29474395 PMCID: PMC5849340 DOI: 10.1371/journal.pgen.1007217] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 03/13/2018] [Accepted: 01/23/2018] [Indexed: 12/31/2022] Open
Abstract
Cellulosic plant biomass is a promising sustainable resource for generating alternative biofuels and biochemicals with microbial factories. But a remaining bottleneck is engineering microbes that are tolerant of toxins generated during biomass processing, because mechanisms of toxin defense are only beginning to emerge. Here, we exploited natural diversity in 165 Saccharomyces cerevisiae strains isolated from diverse geographical and ecological niches, to identify mechanisms of hydrolysate-toxin tolerance. We performed genome-wide association (GWA) analysis to identify genetic variants underlying toxin tolerance, and gene knockouts and allele-swap experiments to validate the involvement of implicated genes. In the process of this work, we uncovered a surprising difference in genetic architecture depending on strain background: in all but one case, knockout of implicated genes had a significant effect on toxin tolerance in one strain, but no significant effect in another strain. In fact, whether or not the gene was involved in tolerance in each strain background had a bigger contribution to strain-specific variation than allelic differences. Our results suggest a major difference in the underlying network of causal genes in different strains, suggesting that mechanisms of hydrolysate tolerance are very dependent on the genetic background. These results could have significant implications for interpreting GWA results and raise important considerations for engineering strategies for industrial strain improvement. Understanding the genetic architecture of complex traits is important for elucidating the genotype-phenotype relationship. Many studies have sought genetic variants that underlie phenotypic variation across individuals, both to implicate causal variants and to inform on architecture. Here we used genome-wide association analysis to identify genes and processes involved in tolerance of toxins found in plant-biomass hydrolysate, an important substrate for sustainable biofuel production. We found substantial variation in whether or not individual genes were important for tolerance across genetic backgrounds. Whether or not a gene was important in a given strain background explained more variation than the alleleic differences in the gene. These results suggest substantial variation in gene contributions, and perhaps underlying mechanisms, of toxin tolerance.
Collapse
Affiliation(s)
- Maria Sardi
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America.,Microbiology Training Program, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Vaishnavi Paithane
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Michael Place
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - De Elegant Robinson
- Microbiology Training Program, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - James Hose
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Dana J Wohlbach
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Audrey P Gasch
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America.,Laboratory of Genetics, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| |
Collapse
|
16
|
Lada AG, Stepchenkova EI, Zhuk AS, Kliver SF, Rogozin IB, Polev DE, Dhar A, Pavlov YI. Recombination Is Responsible for the Increased Recovery of Drug-Resistant Mutants with Hypermutated Genomes in Resting Yeast Diploids Expressing APOBEC Deaminases. Front Genet 2017; 8:202. [PMID: 29312434 PMCID: PMC5733079 DOI: 10.3389/fgene.2017.00202] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Accepted: 11/22/2017] [Indexed: 12/11/2022] Open
Abstract
DNA editing deaminases (APOBECs) are implicated in generation of mutations in somatic cells during tumorigenesis. APOBEC-dependent mutagenesis is thought to occur during transient exposure of unprotected single-stranded DNA. Mutations frequently occur in clusters (kataegis). We investigated mechanisms of mutant generation in growing and resting diploid yeast expressing APOBEC from sea lamprey, PmCDA1, whose kataegistic effect was previously shown to be associated with transcription. We have found that the frequency of canavanine-resistant mutants kept raising after growth cessation, while the profile of transcription remained unchanged. Surprisingly, the overall number of mutations in the genomes did not elevate in resting cells. Thus, mutations were accumulated during vigorous growth stage with both intense replication and transcription. We found that the elevated recovery of can1 mutant clones in non-growing cells is the result of loss of heterozygosity (LOH) leading to clusters of homozygous mutations in the chromosomal regions distal to the reporter gene. We confirmed that recombination frequency in resting cells was elevated by orders of magnitude, suggesting that cells were transiently committed to meiotic levels of recombination, a process referred to in yeast genetics as return-to-growth. In its extreme, on day 6 of starvation, a few mutant clones were haploid, likely resulting from completed meiosis. Distribution of mutations along chromosomes indicated that PmCDA1 was active during ongoing recombination events and sometimes produced characteristic kataegis near initial breakpoints. AID and APOBEC1 behaved similar to PmCDA1. We conclude that replication, transcription, and mitotic recombination contribute to the recovered APOBEC-induced mutations in resting diploids. The mechanism is relevant to the initial stages of oncogenic transformation in terminally differentiated cells, when recombination may lead to the LOH exposing recessive mutations induced by APOBECs in cell's history and to acquisition of new mutations near original break.
Collapse
Affiliation(s)
- Artem G Lada
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, United States.,Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA, United States
| | - Elena I Stepchenkova
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, United States.,Department of Genetics and Biotechnology, Saint Petersburg State University, Saint Petersburg, Russia.,Vavilov Institute of General Genetics, Russian Academy of Sciences, Saint Petersburg, Russia
| | - Anna S Zhuk
- Department of Genetics and Biotechnology, Saint Petersburg State University, Saint Petersburg, Russia.,Vavilov Institute of General Genetics, Russian Academy of Sciences, Saint Petersburg, Russia
| | - Sergei F Kliver
- Department of Genetics and Biotechnology, Saint Petersburg State University, Saint Petersburg, Russia
| | - Igor B Rogozin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, United States.,Institute of Cytology and Genetics, Novosibirsk, Russia
| | - Dmitrii E Polev
- Research Resource Center "Biobank", Research Park, Saint-Petersburg State University, Saint Petersburg, Russia
| | - Alok Dhar
- Department of Genetics, Cell Biology and Anatomy and Vice Chancellor of Research Core, University of Nebraska Medical Center, Omaha, NE, United States
| | - Youri I Pavlov
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, United States.,Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, United States.,Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, United States.,Department of Genetics Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE, United States
| |
Collapse
|
17
|
Schiavone M, Déjean S, Sieczkowski N, Castex M, Dague E, François JM. Integration of Biochemical, Biophysical and Transcriptomics Data for Investigating the Structural and Nanomechanical Properties of the Yeast Cell Wall. Front Microbiol 2017; 8:1806. [PMID: 29085340 PMCID: PMC5649194 DOI: 10.3389/fmicb.2017.01806] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 09/05/2017] [Indexed: 11/24/2022] Open
Abstract
The yeast cell is surrounded by a cell wall conferring protection and resistance to environmental conditions that can be harmful. Identify the molecular cues (genes) which shape the biochemical composition and the nanomechanical properties of the cell wall and the links between these two parameters represent a major issue in the understanding of the biogenesis and the molecular assembly of this essential cellular structure, which may have consequences in diverse biotechnological applications. We addressed this question in two ways. Firstly, we compared the biochemical and biophysical properties using atomic force microscopy (AFM) methods of 4 industrial strains with the laboratory sequenced strain BY4743 and used transcriptome data of these strains to infer biological hypothesis about differences of these properties between strains. This comparative approach showed a 4–6-fold higher hydrophobicity of industrial strains that was correlated to higher expression of genes encoding adhesin and adhesin-like proteins and not to their higher mannans content. The second approach was to employ a multivariate statistical analysis to identify highly correlated variables among biochemical, biophysical and genes expression data. Accordingly, we found a tight association between hydrophobicity and adhesion events that positively correlated with a set of 22 genes in which the main enriched GO function was the sterol metabolic process. We also identified a strong association of β-1,3-glucans with contour length that corresponds to the extension of mannans chains upon pulling the mannosyl units with the lectin-coated AFM tips. This association was positively correlated with a group of 27 genes in which the seripauperin multigene family was highly documented and negatively connected with a set of 23 genes whose main GO biological process was sulfur assimilation/cysteine biosynthetic process. On the other hand, the elasticity modulus was found weakly associated with levels of β-1,6-glucans, and this biophysical variable was positively correlated with a set of genes implicated in microtubules polymerization, tubulin folding and mitotic organization.
Collapse
Affiliation(s)
- Marion Schiavone
- Laboratoire d'Ingénierie des Systèmes Biologiques et Procédés, Institut National des Sciences Appliquées de Toulouse, UPS, INP, Université de ToulouseToulouse, France.,Lallemand SASBlagnac, France
| | | | | | | | - Etienne Dague
- Laboratoire D'analyse et D'architecture des Systèmes du-Centre National de la Recherche Scientifique, Université de ToulouseToulouse, France
| | - Jean M François
- Laboratoire d'Ingénierie des Systèmes Biologiques et Procédés, Institut National des Sciences Appliquées de Toulouse, UPS, INP, Université de ToulouseToulouse, France
| |
Collapse
|
18
|
Couvillion MT, Soto IC, Shipkovenska G, Churchman LS. Synchronized mitochondrial and cytosolic translation programs. Nature 2016; 533:499-503. [PMID: 27225121 PMCID: PMC4964289 DOI: 10.1038/nature18015] [Citation(s) in RCA: 212] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 04/18/2016] [Indexed: 01/21/2023]
Abstract
Oxidative phosphorylation (OXPHOS) is fundamental for life. OXPHOS complexes pose a unique challenge for the cell, because their subunits are encoded on two different genomes, the nuclear genome and the mitochondrial genome. Genomic approaches designed to study nuclear/cytosolic and bacterial gene expression have not been broadly applied to the mitochondrial system; thus the co-regulation of OXPHOS genes remains largely unexplored. Here we globally monitored mitochondrial and nuclear gene expression processes in Saccharomyces cerevisiae during mitochondrial biogenesis, when OXPHOS complexes are synthesized. Nuclear- and mitochondrial-encoded OXPHOS transcript levels do not increase concordantly. Instead, we observe that mitochondrial and cytosolic translation are rapidly and dynamically regulated in a strikingly synchronous fashion. Furthermore, the coordinated translation programs are controlled unidirectionally through the intricate and dynamic control of cytosolic translation. Thus the nuclear genome carefully directs the coordination of mitochondrial and cytosolic translation to orchestrate the timely synthesis of each OXPHOS complex, representing an unappreciated regulatory layer shaping the mitochondrial proteome. Our whole-cell genomic profiling approach establishes a foundation for global gene regulatory studies of mitochondrial biology.
Collapse
Affiliation(s)
- Mary T Couvillion
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Iliana C Soto
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Gergana Shipkovenska
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - L Stirling Churchman
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| |
Collapse
|
19
|
Paci A, Liu PXH, Zhang L, Zhao R. The Proteasome Subunit Rpn8 Interacts with the Small Nucleolar RNA Protein (snoRNP) Assembly Protein Pih1 and Mediates Its Ubiquitin-independent Degradation in Saccharomyces cerevisiae. J Biol Chem 2016; 291:11761-75. [PMID: 27053109 DOI: 10.1074/jbc.m115.702043] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Indexed: 11/06/2022] Open
Abstract
Pih1 is a scaffold protein of the Rvb1-Rvb2-Tah1-Pih1 (R2TP) protein complex, which is conserved in fungi and animals. The chaperone-like activity of the R2TP complex has been implicated in the assembly of multiple protein complexes, such as the small nucleolar RNA protein complex. However, the mechanism of the R2TP complex activity in vivo and the assembly of the complex itself are still largely unknown. Pih1 is an unstable protein and tends to aggregate when expressed alone. The C-terminal fragment of Pih1 contains multiple destabilization factors and acts as a degron when fused to other proteins. In this study, we investigated Pih1 interactors and identified a specific interaction between Pih1 and the proteasome subunit Rpn8 in yeast Saccharomyces cerevisiae when HSP90 co-chaperone Tah1 is depleted. By analyzing truncation mutants, we identified that the C-terminal 30 amino acids of Rpn8 are sufficient for the binding to Pih1 C terminus. With in vitro and in vivo degradation assays, we showed that the Pih1 C-terminal fragment Pih1(282-344) is able to induce a ubiquitin-independent degradation of GFP. Additionally, we demonstrated that truncation of the Rpn8 C-terminal disordered region does not affect proteasome assembly but specifically inhibits the degradation of the GFP-Pih1(282-344) fusion protein in vivo and Pih1 in vitro We propose that Pih1 is a ubiquitin-independent proteasome substrate, and the direct interaction with Rpn8 C terminus mediates its proteasomal degradation.
Collapse
Affiliation(s)
- Alexandr Paci
- From the Department of Biological Sciences, University of Toronto, Toronto, Ontario M1C 1A4, Canada
| | - Peter X H Liu
- From the Department of Biological Sciences, University of Toronto, Toronto, Ontario M1C 1A4, Canada
| | - Lingjie Zhang
- From the Department of Biological Sciences, University of Toronto, Toronto, Ontario M1C 1A4, Canada
| | - Rongmin Zhao
- From the Department of Biological Sciences, University of Toronto, Toronto, Ontario M1C 1A4, Canada
| |
Collapse
|
20
|
Lodi T, Dallabona C, Nolli C, Goffrini P, Donnini C, Baruffini E. DNA polymerase γ and disease: what we have learned from yeast. Front Genet 2015; 6:106. [PMID: 25852747 PMCID: PMC4362329 DOI: 10.3389/fgene.2015.00106] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 03/02/2015] [Indexed: 11/16/2022] Open
Abstract
Mip1 is the Saccharomyces cerevisiae DNA polymerase γ (Pol γ), which is responsible for the replication of mitochondrial DNA (mtDNA). It belongs to the family A of the DNA polymerases and it is orthologs to human POLGA. In humans, mutations in POLG(1) cause many mitochondrial pathologies, such as progressive external ophthalmoplegia (PEO), Alpers' syndrome, and ataxia-neuropathy syndrome, all of which present instability of mtDNA, which results in impaired mitochondrial function in several tissues with variable degrees of severity. In this review, we summarize the genetic and biochemical knowledge published on yeast mitochondrial DNA polymerase from 1989, when the MIP1 gene was first cloned, up until now. The role of yeast is particularly emphasized in (i) validating the pathological mutations found in human POLG and modeled in MIP1, (ii) determining the molecular defects caused by these mutations and (iii) finding the correlation between mutations/polymorphisms in POLGA and mtDNA toxicity induced by specific drugs. We also describe recent findings regarding the discovery of molecules able to rescue the phenotypic defects caused by pathological mutations in Mip1, and the construction of a model system in which the human Pol γ holoenzyme is expressed in yeast and complements the loss of Mip1.
Collapse
Affiliation(s)
- Tiziana Lodi
- Department of Life Sciences, University of Parma Parma, Italy
| | | | - Cecilia Nolli
- Department of Life Sciences, University of Parma Parma, Italy
| | - Paola Goffrini
- Department of Life Sciences, University of Parma Parma, Italy
| | - Claudia Donnini
- Department of Life Sciences, University of Parma Parma, Italy
| | | |
Collapse
|
21
|
High-efficiency genome editing and allele replacement in prototrophic and wild strains of Saccharomyces. Genetics 2014; 198:859-66. [PMID: 25209147 DOI: 10.1534/genetics.114.170118] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Current genome editing techniques available for Saccharomyces yeast species rely on auxotrophic markers, limiting their use in wild and industrial strains and species. Taking advantage of the ancient loss of thymidine kinase in the fungal kingdom, we have developed the herpes simplex virus thymidine kinase gene as a selectable and counterselectable marker that forms the core of novel genome engineering tools called the H: aploid E: ngineering and R: eplacement P: rotocol (HERP) cassettes. Here we show that these cassettes allow a researcher to rapidly generate heterogeneous populations of cells with thousands of independent chromosomal allele replacements using mixed PCR products. We further show that the high efficiency of this approach enables the simultaneous replacement of both alleles in diploid cells. Using these new techniques, many of the most powerful yeast genetic manipulation strategies are now available in wild, industrial, and other prototrophic strains from across the diverse Saccharomyces genus.
Collapse
|
22
|
Kokina A, Kibilds J, Liepins J. Adenine auxotrophy--be aware: some effects of adenine auxotrophy in Saccharomyces cerevisiae strain W303-1A. FEMS Yeast Res 2014; 14:697-707. [PMID: 24661329 DOI: 10.1111/1567-1364.12154] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Revised: 02/24/2014] [Accepted: 03/18/2014] [Indexed: 11/27/2022] Open
Abstract
Adenine auxotrophy is a commonly used genetic marker in haploid yeast strains. Strain W303-1A, which carries the ade2-1 mutation, is widely used in physiological and genetic research. Yeast extract-based rich medium contains a low level of adenine, so that adenine is often depleted before glucose. This could affect the cell physiology of adenine auxotrophs grown in rich medium. The aim of our study was to assess the effects of adenine auxotrophy on cell morphology and stress physiology. Our results show that adenine depletion halts cell division, but that culture optical density continues to increase due to cell swelling. Accumulation of trehalose and a coincident 10-fold increase in desiccation stress tolerance is observed in adenine auxotrophs after adenine depletion, when compared to prototrophs. Under adenine starvation, long-term survival of W303-1A is lower than during carbon starvation, but higher than during leucine starvation. We observed drastic adenine-dependent changes in cell stress physiology, suggesting that results may be biased when adenine auxotrophs are grown in rich media without adenine supplementation.
Collapse
Affiliation(s)
- Agnese Kokina
- Institute of Microbiology and Biotechnology, University of Latvia, Riga, Latvia
| | | | | |
Collapse
|
23
|
Grigoryan M, Shamshurin D, Spicer V, Krokhin OV. Unifying Expression Scale for Peptide Hydrophobicity in Proteomic Reversed Phase High-Pressure Liquid Chromatography Experiments. Anal Chem 2013; 85:10878-86. [DOI: 10.1021/ac402310t] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Marine Grigoryan
- Manitoba Centre for Proteomics and Systems
Biology and ‡Department of Internal Medicine, University of Manitoba, 799 JBRC,
715 McDermot Avenue, Winnipeg, R3E 3P4, Canada
| | - Dmitry Shamshurin
- Manitoba Centre for Proteomics and Systems
Biology and ‡Department of Internal Medicine, University of Manitoba, 799 JBRC,
715 McDermot Avenue, Winnipeg, R3E 3P4, Canada
| | - Victor Spicer
- Manitoba Centre for Proteomics and Systems
Biology and ‡Department of Internal Medicine, University of Manitoba, 799 JBRC,
715 McDermot Avenue, Winnipeg, R3E 3P4, Canada
| | - Oleg V. Krokhin
- Manitoba Centre for Proteomics and Systems
Biology and ‡Department of Internal Medicine, University of Manitoba, 799 JBRC,
715 McDermot Avenue, Winnipeg, R3E 3P4, Canada
| |
Collapse
|
24
|
Rhein VF, Carroll J, Ding S, Fearnley IM, Walker JE. NDUFAF7 methylates arginine 85 in the NDUFS2 subunit of human complex I. J Biol Chem 2013; 288:33016-26. [PMID: 24089531 PMCID: PMC3829151 DOI: 10.1074/jbc.m113.518803] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Complex I (NADH ubiquinone oxidoreductase) in mammalian mitochondria is an L-shaped assembly of 44 subunits. One arm is embedded in the inner membrane with the other protruding ∼100 Å into the matrix of the organelle. The extrinsic arm contains binding sites for NADH and the primary electron acceptor FMN, and it provides a scaffold for seven iron-sulfur clusters that form an electron pathway linking FMN to the terminal electron acceptor, ubiquinone, which is bound in the region of the junction between the arms. The membrane arm contains four antiporter-like domains, probably energetically coupled to the quinone site and involved in pumping protons from the matrix into the intermembrane space contributing to the proton motive force. Complex I is put together from preassembled subcomplexes. Their compositions have been characterized partially, and at least 12 extrinsic assembly factor proteins are required for the assembly of the complex. One such factor, NDUFAF7, is predicted to belong to the family of S-adenosylmethionine-dependent methyltransferases characterized by the presence in their structures of a seven-β-strand protein fold. In the present study, the presence of NDUFAF7 in the mitochondrial matrix has been confirmed, and it has been demonstrated that it is a protein methylase that symmetrically dimethylates the ω-NG,NG′ atoms of residue Arg-85 in the NDUFS2 subunit of complex I. This methylation step occurs early in the assembly of complex I and probably stabilizes a 400-kDa subcomplex that forms the initial nucleus of the peripheral arm and its juncture with the membrane arm.
Collapse
Affiliation(s)
- Virginie F Rhein
- From the Medical Research Council Mitochondrial Biology Unit, Cambridge CB2 0XY, United Kingdom
| | | | | | | | | |
Collapse
|
25
|
Dikicioglu D, Pir P, Oliver SG. Predicting complex phenotype-genotype interactions to enable yeast engineering: Saccharomyces cerevisiae as a model organism and a cell factory. Biotechnol J 2013; 8:1017-34. [PMID: 24031036 PMCID: PMC3910164 DOI: 10.1002/biot.201300138] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Revised: 07/15/2013] [Accepted: 08/07/2013] [Indexed: 11/08/2022]
Abstract
There is an increasing use of systems biology approaches in both "red" and "white" biotechnology in order to enable medical, medicinal, and industrial applications. The intricate links between genotype and phenotype may be explained through the use of the tools developed in systems biology, synthetic biology, and evolutionary engineering. Biomedical and biotechnological research are among the fields that could benefit most from the elucidation of this complex relationship. Researchers have studied fitness extensively to explain the phenotypic impacts of genetic variations. This elaborate network of dependencies and relationships so revealed are further complicated by the influence of environmental effects that present major challenges to our achieving an understanding of the cellular mechanisms leading to healthy or diseased phenotypes or optimized production yields. An improved comprehension of complex genotype-phenotype interactions and their accurate prediction should enable us to more effectively engineer yeast as a cell factory and to use it as a living model of human or pathogen cells in intelligent screens for new drugs. This review presents different methods and approaches undertaken toward improving our understanding and prediction of the growth phenotype of the yeast Saccharomyces cerevisiae as both a model and a production organism.
Collapse
Affiliation(s)
- Duygu Dikicioglu
- Cambridge Systems Biology Centre and Department of Biochemistry, University of Cambridge, CB2 1GA, Cambridge, UK
| | - Pınar Pir
- Babraham Institute, Babraham Research Campus, CB22 3AT, Cambridge, UK
| | - Stephen G Oliver
- Cambridge Systems Biology Centre and Department of Biochemistry, University of Cambridge, CB2 1GA, Cambridge, UK
| |
Collapse
|
26
|
Oxidative damage and mutagenesis in Saccharomyces cerevisiae: genetic studies of pathways affecting replication fidelity of 8-oxoguanine. Genetics 2013; 195:359-67. [PMID: 23893481 PMCID: PMC3781965 DOI: 10.1534/genetics.113.153874] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Oxidative damage to DNA constitutes a major threat to the faithful replication of DNA in all organisms and it is therefore important to understand the various mechanisms that are responsible for repair of such damage and the consequences of unrepaired damage. In these experiments, we make use of a reporter system in Saccharomyces cerevisiae that can measure the specific increase of each type of base pair mutation by measuring reversion to a Trp+ phenotype. We demonstrate that increased oxidative damage due to the absence of the superoxide dismutase gene, SOD1, increases all types of base pair mutations and that mismatch repair (MMR) reduces some, but not all, types of mutations. By analyzing various strains that can revert only via a specific CG → AT transversion in backgrounds deficient in Ogg1 (encoding an 8-oxoG glycosylase), we can study mutagenesis due to a known 8-oxoG base. We show as expected that MMR helps prevent mutagenesis due to this damaged base and that Pol η is important for its accurate replication. In addition we find that its accurate replication is facilitated by template switching, as loss of either RAD5 or MMS2 leads to a significant decrease in accurate replication. We observe that these ogg1 strains accumulate revertants during prolonged incubation on plates, in a process most likely due to retromutagenesis.
Collapse
|
27
|
Murray DB, Haynes K, Tomita M. Redox regulation in respiring Saccharomyces cerevisiae. Biochim Biophys Acta Gen Subj 2011; 1810:945-58. [PMID: 21549177 DOI: 10.1016/j.bbagen.2011.04.005] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 03/16/2011] [Accepted: 04/17/2011] [Indexed: 11/30/2022]
Abstract
BACKGROUND In biological systems, redox reactions are central to most cellular processes and the redox potential of the intracellular compartment dictates whether a particular reaction can or cannot occur. Indeed the widespread use of redox reactions in biological systems makes their detailed description outside the scope of one review. SCOPE OF THE REVIEW Here we will focus on how system-wide redox changes can alter the reaction and transcriptional landscape of Saccharomyces cerevisiae. To understand this we explore the major determinants of cellular redox potential, how these are sensed by the cell and the dynamic responses elicited. MAJOR CONCLUSIONS Redox regulation is a large and complex system that has the potential to rapidly and globally alter both the reaction and transcription landscapes. Although we have a basic understanding of many of the sub-systems and a partial understanding of the transcriptional control, we are far from understanding how these systems integrate to produce coherent responses. We argue that this non-linear system self-organises, and that the output in many cases is temperature-compensated oscillations that may temporally partition incompatible reactions in vivo. GENERAL SIGNIFICANCE Redox biochemistry impinges on most of cellular processes and has been shown to underpin ageing and many human diseases. Integrating the complexity of redox signalling and regulation is perhaps one of the most challenging areas of biology. This article is part of a Special Issue entitled Systems Biology of Microorganisms.
Collapse
Affiliation(s)
- Douglas B Murray
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Japan.
| | | | | |
Collapse
|
28
|
Baruffini E, Ferrero I, Foury F. In vivo analysis of mtDNA replication defects in yeast. Methods 2010; 51:426-36. [PMID: 20206271 DOI: 10.1016/j.ymeth.2010.02.023] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2009] [Revised: 01/27/2010] [Accepted: 02/26/2010] [Indexed: 10/19/2022] Open
Abstract
The yeast Saccharomyces cerevisiae has the capacity to survive large deletions or total loss of mtDNA (petite mutants), and thus in the last few years it has been used as a model system to study defects in mitochondrial DNA (mtDNA) maintenance produced by mutations in genes involved in mtDNA replication. In this paper we describe methods to obtain strains harboring mutations in nuclear genes essential for the integrity of mtDNA, to measure the frequency and the nature of petite mutants, to estimate the point mutation frequency in mtDNA and to determine whether a nuclear mutation is recessive or dominant and, in the latter case, the kind of dominance.
Collapse
Affiliation(s)
- Enrico Baruffini
- Department of Genetics, Biology of Microorganisms, Anthropology, Evolution, Viale Usberti 11/A, 43124 Parma, Italy.
| | | | | |
Collapse
|
29
|
Fontanesi F, Diaz F, Barrientos A. Evaluation of the mitochondrial respiratory chain and oxidative phosphorylation system using yeast models of OXPHOS deficiencies. ACTA ACUST UNITED AC 2009; Chapter 19:Unit19.5. [PMID: 19806592 DOI: 10.1002/0471142905.hg1905s63] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The oxidative phosphorylation (OXPHOS) system consists of five multimeric complexes embedded in the mitochondrial inner membrane. They work in concert to drive the aerobic synthesis of ATP. Mitochondrial and nuclear DNA mutations affecting the accumulation and function of these enzymes are the most common cause of mitochondrial diseases and have also been associated with neurodegeneration and aging. Several approaches for the assessment of the OXPHOS system enzymes have been developed. Based on the methods described elsewhere, this unit describes the creation and study of yeast models of mitochondrial OXPHOS deficiencies.
Collapse
Affiliation(s)
- Flavia Fontanesi
- University of Miami Miller School of Medicine, Miami, Florida, USA
| | | | | |
Collapse
|
30
|
Abstract
Inositol pyrophosphates are involved in a variety of cellular functions, but the specific pathways and/or downstream targets remain poorly characterized. In the present study we use Saccharomyces cerevisiae mutants to examine the potential roles of inositol pyrophosphates in responding to cell damage caused by ROS (reactive oxygen species). Yeast lacking kcs1 [the S. cerevisiae IP6K (inositol hexakisphosphate kinase)] have greatly reduced IP7 (diphosphoinositol pentakisphosphate) and IP8 (bisdiphosphoinositol tetrakisphosphate) levels, and display increased resistance to cell death caused by H2O2, consistent with a sustained activation of DNA repair mechanisms controlled by the Rad53 pathway. Other Rad53-controlled functions, such as actin polymerization, appear unaffected by inositol pyrophosphates. Yeast lacking vip1 [the S. cerevisiae PP-IP5K (also known as IP7K, IP7 kinase)] accumulate large amounts of the inositol pyrophosphate IP7, but have no detectable IP8, indicating that this enzyme represents the physiological IP7 kinase. Similar to kcs1Delta yeast, vip1Delta cells showed an increased resistance to cell death caused by H2O2, indicating that it is probably the double-pyrophosphorylated form of IP8 [(PP)2-IP4] which mediates the H2O2 response. However, these inositol pyrophosphates are not involved in directly sensing DNA damage, as kcs1Delta cells are more responsive to DNA damage caused by phleomycin. We observe in vivo a rapid decrease in cellular inositol pyrophosphate levels following exposure to H2O2, and an inhibitory effect of H2O2 on the enzymatic activity of Kcs1 in vitro. Furthermore, parallel cysteine mutagenesis studies performed on mammalian IP6K1 are suggestive that the ROS signal might be transduced by the direct modification of this evolutionarily conserved class of enzymes.
Collapse
|
31
|
Current awareness on yeast. Yeast 1990. [DOI: 10.1002/yea.1620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
|