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Ghosh S, Sanchez AM, Schwer B, Prucker I, Jork N, Jessen HJ, Shuman S. Activities and genetic interactions of fission yeast Aps1, a Nudix-type inositol pyrophosphatase and inorganic polyphosphatase. mBio 2024; 15:e0108424. [PMID: 38940614 PMCID: PMC11323792 DOI: 10.1128/mbio.01084-24] [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: 04/11/2024] [Accepted: 05/28/2024] [Indexed: 06/29/2024] Open
Abstract
Inositol pyrophosphate 1,5-IP8 regulates expression of a fission yeast phosphate homeostasis regulon, comprising phosphate acquisition genes pho1, pho84, and tgp1, via its action as an agonist of precocious termination of transcription of the upstream lncRNAs that repress PHO mRNA synthesis. 1,5-IP8 levels are dictated by a balance between the Asp1 N-terminal kinase domain that converts 5-IP7 to 1,5-IP8 and three inositol pyrophosphatases-the Asp1 C-terminal domain (a histidine acid phosphatase), Siw14 (a cysteinyl-phosphatase), and Aps1 (a Nudix enzyme). In this study, we report the biochemical and genetic characterization of Aps1 and an analysis of the effects of Asp1, Siw14, and Aps1 mutations on cellular inositol pyrophosphate levels. We find that Aps1's substrate repertoire embraces inorganic polyphosphates, 5-IP7, 1-IP7, and 1,5-IP8. Aps1 displays a ~twofold preference for hydrolysis of 1-IP7 versus 5-IP7 and aps1∆ cells have twofold higher levels of 1-IP7 vis-à-vis wild-type cells. While neither Aps1 nor Siw14 is essential for growth, an aps1∆ siw14∆ double mutation is lethal on YES medium. This lethality is a manifestation of IP8 toxicosis, whereby excessive 1,5-IP8 drives derepression of tgp1, leading to Tgp1-mediated uptake of glycerophosphocholine. We were able to recover an aps1∆ siw14∆ mutant on ePMGT medium lacking glycerophosphocholine and to suppress the severe growth defect of aps1∆ siw14∆ on YES by deleting tgp1. However, the severe growth defect of an aps1∆ asp1-H397A strain could not be alleviated by deleting tgp1, suggesting that 1,5-IP8 levels in this double-pyrophosphatase mutant exceed a threshold beyond which overzealous termination affects other genes, which results in cytotoxicity. IMPORTANCE Repression of the fission yeast PHO genes tgp1, pho1, and pho84 by lncRNA-mediated interference is sensitive to changes in the metabolism of 1,5-IP8, a signaling molecule that acts as an agonist of precocious lncRNA termination. 1,5-IP8 is formed by phosphorylation of 5-IP7 and catabolized by inositol pyrophosphatases from three distinct enzyme families: Asp1 (a histidine acid phosphatase), Siw14 (a cysteinyl phosphatase), and Aps1 (a Nudix hydrolase). This study entails a biochemical characterization of Aps1 and an analysis of how Asp1, Siw14, and Aps1 mutations impact growth and inositol pyrophosphate pools in vivo. Aps1 catalyzes hydrolysis of inorganic polyphosphates, 5-IP7, 1-IP7, and 1,5-IP8 in vitro, with a ~twofold preference for 1-IP7 over 5-IP7. aps1∆ cells have twofold higher levels of 1-IP7 than wild-type cells. An aps1∆ siw14∆ double mutation is lethal because excessive 1,5-IP8 triggers derepression of tgp1, leading to toxic uptake of glycerophosphocholine.
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Affiliation(s)
- Shreya Ghosh
- Molecular Biology Program, Sloan Kettering Institute, New York, New York, USA
| | - Ana M. Sanchez
- Molecular Biology Program, Sloan Kettering Institute, New York, New York, USA
- Gerstner Sloan Kettering Graduate School of Biomedical Sciences, New York, New York, USA
| | - Beate Schwer
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York, USA
| | - Isabel Prucker
- Institute of Organic Chemistry, University of Freiburg, Freiburg, Germany
| | - Nikolaus Jork
- Institute of Organic Chemistry, University of Freiburg, Freiburg, Germany
| | - Henning J. Jessen
- Institute of Organic Chemistry, University of Freiburg, Freiburg, Germany
- CIBSS - Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Stewart Shuman
- Molecular Biology Program, Sloan Kettering Institute, New York, New York, USA
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Schwer B, Innokentev A, Sanchez AM, Garg A, Shuman S. Suppression of inositol pyrophosphate toxicosis and hyper-repression of the fission yeast PHO regulon by loss-of-function mutations in chromatin remodelers Snf22 and Sol1. mBio 2024; 15:e0125224. [PMID: 38899862 PMCID: PMC11253589 DOI: 10.1128/mbio.01252-24] [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: 04/30/2024] [Accepted: 05/06/2024] [Indexed: 06/21/2024] Open
Abstract
Inositol pyrophosphates are signaling molecules that regulate cellular phosphate homeostasis in eukaryal taxa. In fission yeast, where the phosphate regulon (comprising phosphate acquisition genes pho1, pho84, and tgp1) is repressed under phosphate-replete conditions by lncRNA-mediated transcriptional interference, mutations of inositol pyrophosphatases that increase IP8 levels derepress the PHO regulon by eliciting precocious termination of lncRNA transcription. Asp1 pyrophosphatase mutations resulting in too much IP8 are cytotoxic in YES medium owing to overexpression of glycerophosphodiester transporter Tgp1. IP8 toxicosis is ameliorated by mutations in cleavage/polyadenylation and termination factors, perturbations of the Pol2 CTD code, and mutations in SPX domain proteins that act as inositol pyrophosphate sensors. Here, we show that IP8 toxicity is alleviated by deletion of snf22+, the gene encoding the ATPase subunit of the SWI/SNF chromatin remodeling complex, by an ATPase-inactivating snf22-(D996A-E997A) allele, and by deletion of the gene encoding SWI/SNF subunit Sol1. Deletion of snf22+ hyper-repressed pho1 expression in phosphate-replete cells; suppressed the pho1 derepression elicited by mutations in Pol2 CTD, termination factor Seb1, Asp1 pyrophosphatase, and 14-3-3 protein Rad24 (that favor precocious prt lncRNA termination); and delayed pho1 induction during phosphate starvation. RNA analysis and lack of mutational synergies suggest that Snf22 is not impacting 3'-processing/termination. Using reporter assays, we find that Snf22 is important for the activity of the tgp1 and pho1 promoters, but not for the promoters that drive the synthesis of the PHO-repressive lncRNAs. Transcription profiling of snf22∆ and snf22-(D996A-E997A) cells identified an additional set of 66 protein-coding genes that were downregulated in both mutants.IMPORTANCERepression of the fission yeast PHO genes tgp1, pho1, and pho84 by lncRNA-mediated interference is sensitive to inositol pyrophosphate dynamics. Cytotoxic asp1-STF alleles derepress the PHO genes via the action of IP8 as an agonist of precocious lncRNA 3'-processing/termination. IP8 toxicosis is alleviated by mutations of the Pol2 CTD and the 3'-processing/termination machinery that dampen the impact of toxic IP8 levels on termination. In this study, a forward genetic screen revealed that IP8 toxicity is suppressed by mutations of the Snf22 and Sol1 subunits of the SWI/SNF chromatin remodeling complex. Genetic and biochemical evidence indicates that the SWI/SNF is not affecting 3'-processing/termination or lncRNA promoter activity. Rather, SWI/SNF is critical for firing the PHO mRNA promoters. Our results implicate the ATP-dependent nucleosome remodeling activity of SWI/SNF as necessary to ensure full access of PHO-activating transcription factor Pho7 to its binding sites in the PHO mRNA promoters.
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Affiliation(s)
- Beate Schwer
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York, USA
| | - Aleksei Innokentev
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Ana M. Sanchez
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York, USA
- Gerstner Sloan Kettering Graduate School of Biomedical Sciences, New York, New York, USA
| | - Angad Garg
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Stewart Shuman
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York, USA
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Garg A, Sanchez AM, Schwer B, Shuman S. Factors governing the transcriptome changes and chronological lifespan of fission yeast during phosphate starvation. J Biol Chem 2024; 300:105718. [PMID: 38311173 PMCID: PMC10910108 DOI: 10.1016/j.jbc.2024.105718] [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: 11/30/2023] [Revised: 01/23/2024] [Accepted: 01/27/2024] [Indexed: 02/10/2024] Open
Abstract
Starvation of Schizosaccharomyces pombe for inorganic phosphate elicits adaptive transcriptome changes in which mRNAs driving ribosome biogenesis, tRNA biogenesis, and translation are globally downregulated, while those for autophagy and phosphate mobilization are upregulated. Here, we interrogated three components of the starvation response: upregulated autophagy; the role of transcription factor Pho7 (an activator of the PHO regulon); and upregulated expression of ecl3, one of three paralogous genes (ecl1, ecl2, and ecl3) collectively implicated in cell survival during other nutrient stresses. Ablation of autophagy factor Atg1 resulted in early demise of phosphate-starved fission yeast, as did ablation of Pho7. Transcriptome profiling of phosphate-starved pho7Δ cells highlighted Pho7 as an activator of genes involved in phosphate acquisition and mobilization, not limited to the original three-gene PHO regulon, and additional starvation-induced genes (including ecl3) not connected to phosphate dynamics. Pho7-dependent gene induction during phosphate starvation tracked with the presence of Pho7 DNA-binding elements in the gene promoter regions. Fewer ribosome protein genes were downregulated in phosphate-starved pho7Δ cells versus WT, which might contribute to their shortened lifespan. An ecl3Δ mutant elicited no gene expression changes in phosphate-replete cells and had no impact on survival during phosphate starvation. By contrast, pan-ecl deletion (ecl123Δ) curtailed lifespan during chronic phosphate starvation. Phosphate-starved ecl123Δ cells experienced a more widespread downregulation of mRNAs encoding aminoacyl tRNA synthetases vis-à-vis WT or pho7Δ cells. Collectively, these results enhance our understanding of fission yeast phosphate homeostasis and survival during nutrient deprivation.
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Affiliation(s)
- Angad Garg
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Ana M Sanchez
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York, USA; Gerstner Sloan Kettering Graduate School of Biomedical Sciences, New York, New York, USA
| | - Beate Schwer
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York, USA
| | - Stewart Shuman
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York, USA.
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Bednor L, Sanchez AM, Garg A, Shuman S, Schwer B. Genetic suppressor screen identifies Tgp1 (glycerophosphocholine transporter), Kcs1 (IP 6 kinase), and Plc1 (phospholipase C) as determinants of inositol pyrophosphate toxicosis in fission yeast. mBio 2024; 15:e0306223. [PMID: 38133430 PMCID: PMC10865970 DOI: 10.1128/mbio.03062-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 11/21/2023] [Indexed: 12/23/2023] Open
Abstract
The inositol pyrophosphate signaling molecule 1,5-IP8 is an agonist of RNA 3'-processing and transcription termination in fission yeast that regulates the expression of phosphate acquisition genes pho1, pho84, and tgp1. IP8 is synthesized from 5-IP7 by the Asp1 N-terminal kinase domain and catabolized by the Asp1 C-terminal pyrophosphatase domain. asp1-STF mutations that delete or inactivate the Asp1 pyrophosphatase domain elicit growth defects in yeast extract with supplements (YES) medium ranging from severe sickness to lethality. We now find that the toxicity of asp1-STF mutants is caused by a titratable constituent of yeast extract. Via a genetic screen for spontaneous suppressors, we identified a null mutation of glycerophosphodiester transporter tgp1 that abolishes asp1-STF toxicity in YES medium. This result, and the fact that tgp1 mRNA expression is increased by >40-fold in asp1-STF cells, prompted discovery that: (i) glycerophosphocholine (GPC) recapitulates the toxicity of yeast extract to asp1-STF cells in a Tgp1-dependent manner, and (ii) induced overexpression of tgp1 in asp1+ cells also elicits toxicity dependent on GPC. asp1-STF suppressor screens yielded a suite of single missense mutations in the essential IP6 kinase Kcs1 that generates 5-IP7, the immediate precursor to IP8. Transcription profiling of the kcs1 mutants in an asp1+ background revealed the downregulation of the same phosphate acquisition genes that were upregulated in asp1-STF cells. The suppressor screen also returned single missense mutations in Plc1, the fission yeast phospholipase C enzyme that generates IP3, an upstream precursor for the synthesis of inositol pyrophosphates.IMPORTANCEThe inositol pyrophosphate metabolite 1,5-IP8 governs repression of fission yeast phosphate homeostasis genes pho1, pho84, and tgp1 by lncRNA-mediated transcriptional interference. Asp1 pyrophosphatase mutations that increase IP8 levels elicit precocious lncRNA termination, leading to derepression of the PHO genes. Deletions of the Asp1 pyrophosphatase domain result in growth impairment or lethality via IP8 agonism of transcription termination. It was assumed that IP8 toxicity ensues from dysregulation of essential genes. In this study, a suppressor screen revealed that IP8 toxicosis of Asp1 pyrophosphatase mutants is caused by: (i) a >40-fold increase in the expression of the inessential tgp1 gene encoding a glycerophosphodiester transporter and (ii) the presence of glycerophosphocholine in the growth medium. The suppressor screen yielded missense mutations in two upstream enzymes of inositol polyphosphate metabolism: the phospholipase C enzyme Plc1 that generates IP3 and the essential Kcs1 kinase that converts IP6 to 5-IP7, the immediate precursor of IP8.
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Affiliation(s)
- Lauren Bednor
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, USA
- Molecular Biology Program, Sloan-Kettering Institute, New York, USA
- Weill Cornell Graduate School of Medical Sciences, New York, USA
| | - Ana M. Sanchez
- Molecular Biology Program, Sloan-Kettering Institute, New York, USA
- Gerstner Sloan Kettering Graduate School of Biomedical Sciences, New York, USA
| | - Angad Garg
- Molecular Biology Program, Sloan-Kettering Institute, New York, USA
| | - Stewart Shuman
- Molecular Biology Program, Sloan-Kettering Institute, New York, USA
| | - Beate Schwer
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, USA
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Fidler E, Dwyer K, Ansari A. Ssu72: a versatile protein with functions in transcription and beyond. Front Mol Biosci 2024; 11:1332878. [PMID: 38304578 PMCID: PMC10830811 DOI: 10.3389/fmolb.2024.1332878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 01/08/2024] [Indexed: 02/03/2024] Open
Abstract
Eukaryotic transcription is a complex process involving a vast network of protein and RNA factors that influence gene expression. The main player in transcription is the RNA polymerase that synthesizes the RNA from the DNA template. RNA polymerase II (RNAPII) transcribes all protein coding genes and some noncoding RNAs in eukaryotic cells. The polymerase is aided by interacting partners that shuttle it along the gene for initiation, elongation and termination of transcription. One of the many factors that assist RNAPII in transcription of genes is Ssu72. It is a carboxy-terminal-domain (CTD)-phosphatase that plays pleiotropic roles in the transcription cycle. It is essential for cell viability in Saccharomyces cerevisiae, the organism in which it was discovered. The homologues of Ssu72 have been identified in humans, mice, plants, flies, and fungi thereby suggesting the evolutionarily conserved nature of the protein. Recent studies have implicated the factor beyond the confines of transcription in homeostasis and diseases.
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Affiliation(s)
| | | | - Athar Ansari
- Department of Biological Sciences, Wayne State University, Detroit, MI, United States
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Garg A, Schwer B, Shuman S. Fission yeast poly(A) polymerase active site mutation Y86D alleviates the rad24Δ asp1-H397A synthetic growth defect and up-regulates mRNAs targeted by MTREC and Mmi1. RNA (NEW YORK, N.Y.) 2023; 29:1738-1753. [PMID: 37586723 PMCID: PMC10578478 DOI: 10.1261/rna.079722.123] [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: 05/15/2023] [Accepted: 07/30/2023] [Indexed: 08/18/2023]
Abstract
Expression of fission yeast Pho1 acid phosphatase is repressed under phosphate-replete conditions by transcription of an upstream prt lncRNA that interferes with the pho1 mRNA promoter. lncRNA-mediated interference is alleviated by genetic perturbations that elicit precocious lncRNA 3'-processing and transcription termination, such as (i) the inositol pyrophosphate pyrophosphatase-defective asp1-H397A allele, which results in elevated levels of IP8, and (ii) absence of the 14-3-3 protein Rad24. Combining rad24Δ with asp1-H397A causes a severe synthetic growth defect. A forward genetic screen for SRA (Suppressor of Rad24 Asp1-H397A) mutations identified a novel missense mutation (Tyr86Asp) of Pla1, the essential poly(A) polymerase subunit of the fission yeast cleavage and polyadenylation factor (CPF) complex. The pla1-Y86D allele was viable but slow-growing in an otherwise wild-type background. Tyr86 is a conserved active site constituent that contacts the RNA primer 3' nt and the incoming ATP. The Y86D mutation elicits a severe catalytic defect in RNA-primed poly(A) synthesis in vitro and in binding to an RNA primer. Yet, analyses of specific mRNAs indicate that poly(A) tails in pla1-Y86D cells are not different in size than those in wild-type cells, suggesting that other RNA interactors within CPF compensate for the defects of isolated Pla1-Y86D. Transcriptome profiling of pla1-Y86D cells revealed the accumulation of multiple RNAs that are normally rapidly degraded by the nuclear exosome under the direction of the MTREC complex, with which Pla1 associates. We suggest that Pla1-Y86D is deficient in the hyperadenylation of MTREC targets that precedes their decay by the exosome.
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Affiliation(s)
- Angad Garg
- Molecular Biology Program, Sloan-Kettering Institute, New York, New York 10065, USA
| | - Beate Schwer
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York 10065, USA
| | - Stewart Shuman
- Molecular Biology Program, Sloan-Kettering Institute, New York, New York 10065, USA
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Sanchez AM, Schwer B, Jork N, Jessen HJ, Shuman S. Activities, substrate specificity, and genetic interactions of fission yeast Siw14, a cysteinyl-phosphatase-type inositol pyrophosphatase. mBio 2023; 14:e0205623. [PMID: 37772819 PMCID: PMC10653929 DOI: 10.1128/mbio.02056-23] [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: 08/06/2023] [Accepted: 08/09/2023] [Indexed: 09/30/2023] Open
Abstract
IMPORTANCE The inositol pyrophosphate signaling molecule 1,5-IP8 modulates fission yeast phosphate homeostasis via its action as an agonist of RNA 3'-processing and transcription termination. Cellular 1,5-IP8 levels are determined by a balance between the activities of the inositol polyphosphate kinase Asp1 and several inositol pyrophosphatase enzymes. Here, we characterize Schizosaccharomyces pombe Siw14 (SpSiw14) as a cysteinyl-phosphatase-family pyrophosphatase enzyme capable of hydrolyzing the phosphoanhydride substrates inorganic pyrophosphate, inorganic polyphosphate, and inositol pyrophosphates 5-IP7, 1-IP7, and 1,5-IP8. Genetic analyses implicate SpSiw14 in 1,5-IP8 catabolism in vivo, insofar as: loss of SpSiw14 activity is lethal in the absence of the Nudix-type inositol pyrophosphatase enzyme Aps1; and siw14∆ aps1∆ lethality depends on synthesis of 1,5-IP8 by the Asp1 kinase. Suppression of siw14∆ aps1∆ lethality by loss-of-function mutations of 3'-processing/termination factors points to precocious transcription termination as the cause of 1,5-IP8 toxicosis.
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Affiliation(s)
- Ana M. Sanchez
- Molecular Biology Program, Sloan Kettering Institute, New York, New York, USA
- Gerstner Sloan Kettering Graduate School of Biomedical Sciences, New York, New York, USA
| | - Beate Schwer
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York, USA
| | - Nikolaus Jork
- Institute of Organic Chemistry and Centre for Integrative Biological Signaling Studies, University of Freiburg, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine, University of Freiburg, Freiburg, Germany
| | - Henning J. Jessen
- Institute of Organic Chemistry and Centre for Integrative Biological Signaling Studies, University of Freiburg, Freiburg, Germany
| | - Stewart Shuman
- Molecular Biology Program, Sloan Kettering Institute, New York, New York, USA
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Sanchez AM, Garg A, Schwer B, Shuman S. Duf89 abets lncRNA control of fission yeast phosphate homeostasis via its antagonism of precocious lncRNA transcription termination. RNA (NEW YORK, N.Y.) 2023; 29:808-825. [PMID: 36882296 PMCID: PMC10187668 DOI: 10.1261/rna.079595.123] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 02/13/2023] [Indexed: 05/18/2023]
Abstract
Fission yeast phosphate homeostasis gene pho1 is actively repressed during growth in phosphate-rich medium by transcription in cis of a long noncoding (lnc) RNA from the 5' flanking prt(nc-pho1) gene. Pho1 expression is: (i) derepressed by genetic maneuvers that favor precocious lncRNA 3'-processing and termination, in response to DSR and PAS signals in prt; and (ii) hyperrepressed in genetic backgrounds that dampen 3'-processing/termination efficiency. Governors of 3'-processing/termination include the RNA polymerase CTD code, the CPF (cleavage and polyadenylation factor) complex, termination factors Seb1 and Rhn1, and the inositol pyrophosphate signaling molecule 1,5-IP8 Here, we present genetic and biochemical evidence that fission yeast Duf89, a metal-dependent phosphatase/pyrophosphatase, is an antagonist of precocious 3'-processing/termination. We show that derepression of pho1 in duf89Δ cells correlates with squelching the production of full-length prt lncRNA and is erased or attenuated by: (i) DSR/PAS mutations in prt; (ii) loss-of-function mutations in components of the 3'-processing and termination machinery; (iii) elimination of the CTD Thr4-PO4 mark; (iv) interdicting CTD prolyl isomerization by Pin1; (v) inactivating the Asp1 kinase that synthesizes IP8; and (vi) loss of the putative IP8 sensor Spx1. The findings that duf89Δ is synthetically lethal with pho1-derepressive mutations CTD-S7A and aps1Δ-and that this lethality is rescued by CTD-T4A, CPF/Rhn1/Pin1 mutations, and spx1Δ-implicate Duf89 more broadly as a collaborator in cotranscriptional regulation of essential fission yeast genes. The duf89-D252A mutation, which abolishes Duf89 phosphohydrolase activity, phenocopied duf89 +, signifying that duf89Δ phenotypes are a consequence of Duf89 protein absence, not absence of Duf89 catalysis.
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Affiliation(s)
- Ana M Sanchez
- Molecular Biology Program, Sloan Kettering Institute, New York, New York 10065, USA
- Gerstner Sloan Kettering Graduate School of Biomedical Sciences, New York, New York 10065, USA
| | - Angad Garg
- Molecular Biology Program, Sloan Kettering Institute, New York, New York 10065, USA
| | - Beate Schwer
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York 10065, USA
| | - Stewart Shuman
- Molecular Biology Program, Sloan Kettering Institute, New York, New York 10065, USA
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Ohtsuka H, Sakata H, Kitazaki Y, Tada M, Shimasaki T, Otsubo Y, Maekawa Y, Kobayashi M, Imada K, Yamashita A, Aiba H. The ecl family gene ecl3+ is induced by phosphate starvation and contributes to sexual differentiation in fission yeast. J Cell Sci 2023; 136:287015. [PMID: 36779416 PMCID: PMC10038150 DOI: 10.1242/jcs.260759] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 02/07/2023] [Indexed: 02/14/2023] Open
Abstract
In Schizosaccharomyces pombe, ecl family genes are induced by several signals, such as starvation of various nutrients, including sulfur, amino acids and Mg2+, and environmental stress, including heat or oxidative stress. These genes mediate appropriate cellular responses and contribute to the maintenance of cell viability and induction of sexual differentiation. Although this yeast has three ecl family genes with overlapping functions, any environmental conditions that induce ecl3+ remain unidentified. We demonstrate that ecl3+ is induced by phosphate starvation, similar to its chromosomally neighboring genes, pho1+ and pho84+, which respectively encode an extracellular acid phosphatase and an inorganic phosphate transporter. ecl3+ expression was induced by the transcription factor Pho7 and affected by the cyclin-dependent kinase (CDK)-activating kinase Csk1. Phosphate starvation induced G1 arrest and sexual differentiation via ecl family genes. Biochemical analyses suggested that this G1 arrest was mediated by the stabilization of the CDK inhibitor Rum1, which was dependent on ecl family genes. This study shows that ecl family genes are required for appropriate responses to phosphate starvation and provides novel insights into the diversity and similarity of starvation responses.
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Affiliation(s)
- Hokuto Ohtsuka
- Laboratory of Molecular Microbiology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan
| | - Hiroki Sakata
- Laboratory of Molecular Microbiology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan
| | - Yuto Kitazaki
- Laboratory of Molecular Microbiology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan
| | - Masanobu Tada
- Laboratory of Molecular Microbiology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan
| | - Takafumi Shimasaki
- Laboratory of Molecular Microbiology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan
| | - Yoko Otsubo
- Interdisciplinary Research Unit, National Institute for Basic Biology, Okazaki, Aichi 444-858, Japan
- National Institute for Fusion Science, Toki, Gifu 509-5292, Japan
- Center for Novel Science Initiatives, National Institutes of Natural Sciences, Okazaki, Aichi 444-8585, Japan
| | - Yasukichi Maekawa
- Laboratory of Molecular Microbiology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan
| | - Mikuto Kobayashi
- Laboratory of Molecular Microbiology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan
| | - Kazuki Imada
- Department of Chemistry and Biochemistry, National Institute of Technology (KOSEN), Suzuka College, Suzuka 510-0294, Japan
- Department of Biology, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Akira Yamashita
- Interdisciplinary Research Unit, National Institute for Basic Biology, Okazaki, Aichi 444-858, Japan
- Center for Low-temperature Plasma Sciences, Nagoya University, Nagoya, Aichi 464-8603, Japan
| | - Hirofumi Aiba
- Laboratory of Molecular Microbiology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan
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