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Saha D, Pramanik A, Freville A, Siddiqui AA, Pal U, Banerjee C, Nag S, Debsharma S, Pramanik S, Mazumder S, Maiti NC, Datta S, van Ooij C, Bandyopadhyay U. Structure-function analysis of nucleotide housekeeping protein HAM1 from human malaria parasite Plasmodium falciparum. FEBS J 2024. [PMID: 39003571 DOI: 10.1111/febs.17216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2024] [Revised: 03/29/2024] [Accepted: 06/20/2024] [Indexed: 07/15/2024]
Abstract
Non-canonical nucleotides, generated as oxidative metabolic by-products, significantly threaten the genome integrity of Plasmodium falciparum and thereby, their survival, owing to their mutagenic effects. PfHAM1, an evolutionarily conserved inosine/xanthosine triphosphate pyrophosphohydrolase, maintains nucleotide homeostasis in the malaria parasite by removing non-canonical nucleotides, although structure-function intricacies are hitherto poorly reported. Here, we report the X-ray crystal structure of PfHAM1, which revealed a homodimeric structure, additionally validated by size-exclusion chromatography-multi-angle light scattering analysis. The two monomeric units in the dimer were aligned in a parallel fashion, and critical residues associated with substrate and metal binding were identified, wherein a notable structural difference was observed in the β-sheet main frame compared to human inosine triphosphate pyrophosphatase. PfHAM1 exhibited Mg++-dependent pyrophosphohydrolase activity and the highest binding affinity to dITP compared to other non-canonical nucleotides as measured by isothermal titration calorimetry. Modifying the pfham1 genomic locus followed by live-cell imaging of expressed mNeonGreen-tagged PfHAM1 demonstrated its ubiquitous presence in the cytoplasm across erythrocytic stages with greater expression in trophozoites and schizonts. Interestingly, CRISPR-Cas9/DiCre recombinase-guided pfham1-null P. falciparum survived in culture under standard growth conditions, indicating its assistive role in non-canonical nucleotide clearance during intra-erythrocytic stages. This is the first comprehensive structural and functional report of PfHAM1, an atypical nucleotide-cleansing enzyme in P. falciparum.
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Affiliation(s)
- Debanjan Saha
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Atanu Pramanik
- Division of Structural Biology & Bioinformatics, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Aline Freville
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, UK
| | - Asim Azhar Siddiqui
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Uttam Pal
- Division of Structural Biology & Bioinformatics, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Chinmoy Banerjee
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Shiladitya Nag
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Subhashis Debsharma
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Saikat Pramanik
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Somnath Mazumder
- Department of Zoology, Raja Peary Mohan College, Uttarpara, India
| | - Nakul C Maiti
- Division of Structural Biology & Bioinformatics, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Saumen Datta
- Division of Structural Biology & Bioinformatics, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Christiaan van Ooij
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, UK
| | - Uday Bandyopadhyay
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, Kolkata, India
- Department of Biological Sciences, Bose Institute, Kolkata, India
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Lindsey AR, Tennessen JM, Gelaw MA, Jones MW, Parish AJ, Newton IL, Nemkov T, D'Alessandro A, Rai M, Stark N. The intracellular symbiont Wolbachia alters Drosophila development and metabolism to buffer against nutritional stress. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.01.20.524972. [PMID: 36711506 PMCID: PMC9882369 DOI: 10.1101/2023.01.20.524972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The intracellular bacterium Wolbachia is a common symbiont of many arthropods and nematodes, well studied for its impacts on host reproductive biology. However, its broad success as a vertically transmitted infection cannot be attributed to manipulations of host reproduction alone. Using the Drosophila melanogaster model and their natively associated Wolbachia strain " w Mel", we show that Wolbachia infection supports fly development and buffers against nutritional stress. Wolbachia infection across several fly genotypes and a range of nutrient conditions resulted in reduced pupal mortality, increased adult emergence, and larger size. We determined that the exogenous supplementation of pyrimidines partially rescued developmental phenotypes in the Wolbachia -free flies, and that Wolbachia titers were responsive to reduced gene expression of the fly's de novo pyrimidine synthesis pathway. In parallel, transcriptomic and metabolomic analyses indicated that Wolbachia impacts larval biology far beyond pyrimidine metabolism. Wolbachia -infected larvae had strong signatures of shifts in glutathione and mitochondrial metabolism, plus significant changes in the expression of key developmental regulators including Notch , the insulin receptor ( lnR ), and the juvenile hormone receptor Methoprene-tolerant ( Met ). We propose that Wolbachia acts as a beneficial symbiont to support fly development and enhance host fitness, especially during periods of nutrient stress. SIGNIFICANCE Wolbachia is a bacterial symbiont of arthropods and nematodes, well described for its manipulations of arthropod reproduction. However, many have theorized there must be more to this symbiosis, even in well-studied Wolbachia- host relationships such as with Drosophila . Reproductive impacts alone cannot explain the success and ubiquity of this bacterium. Here, we use Drosophila melanogaster and their native Wolbachia infections to show that Wolbachia supports fly development and significantly buffers flies against nutritional stress. These developmental advantages might help explain the ubiquity of Wolbachia infections.
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Zheng YY, Reddy K, Vangaveti S, Sheng J. Inosine-Induced Base Pairing Diversity during Reverse Transcription. ACS Chem Biol 2024; 19:348-356. [PMID: 38252964 PMCID: PMC10877575 DOI: 10.1021/acschembio.3c00555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 11/27/2023] [Accepted: 01/10/2024] [Indexed: 01/24/2024]
Abstract
A-to-I editing catalyzed by adenosine deaminase acting on RNAs impacts numerous physiological and biochemical processes that are essential for cellular functions and is a big contributor to the infectivity of certain RNA viruses. The outcome of this deamination leads to changes in the eukaryotic transcriptome functionally resembling A-G transitions since inosine preferentially pairs with cytosine. Moreover, hyper-editing or multiple A to G transitions in clusters were detected in measles virus. Inosine modifications either directly on viral RNA or on cellular RNA can have antiviral or pro-viral repercussions. While many of the significant roles of inosine in cellular RNAs are well understood, the effects of hyper-editing of A to I on viral polymerase activity during RNA replication remain elusive. Moreover, biological strategies such as molecular cloning and RNA-seq for transcriptomic interrogation rely on RT-polymerase chain reaction with little to no emphasis placed on the first step, reverse transcription, which may reshape the sequencing results when hypermodification is present. In this study, we systematically explore the influence of inosine modification, varying the number and position of inosines, on decoding outcomes using three different reverse transcriptases (RTs) followed by standard Sanger sequencing. We find that inosine alone or in clusters can differentially affect the RT activity. To gain structural insights into the accommodation of inosine in the polymerase site of HIV-1 reverse transcriptase (HIV-1-RT) and how this structural context affects the base pairing rules for inosine, we performed molecular dynamics simulations of the HIV-1-RT. The simulations highlight the importance of the protein-nucleotide interaction as a critical factor in deciphering the base pairing behavior of inosine clusters. This effort sets the groundwork for decrypting the physiological significance of inosine and linking the fidelity of reverse transcriptase and the possible diverse transcription outcomes of cellular RNAs and/or viral RNAs where hyper-edited inosines are present in the transcripts.
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Affiliation(s)
- Ya Ying Zheng
- Department
of Chemistry, University at Albany, State
University of New York, 1400 Washington Avenue, Albany, New York 12222, United States
- The
RNA Institute, University at Albany, State
University of New York, 1400 Washington Avenue, Albany, New York 12222, United States
| | - Kaalak Reddy
- The
RNA Institute, University at Albany, State
University of New York, 1400 Washington Avenue, Albany, New York 12222, United States
| | - Sweta Vangaveti
- The
RNA Institute, University at Albany, State
University of New York, 1400 Washington Avenue, Albany, New York 12222, United States
| | - Jia Sheng
- Department
of Chemistry, University at Albany, State
University of New York, 1400 Washington Avenue, Albany, New York 12222, United States
- The
RNA Institute, University at Albany, State
University of New York, 1400 Washington Avenue, Albany, New York 12222, United States
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Mahillon M, Brodard J, Dubuis N, Gugerli P, Blouin AG, Schumpp O. Mixed infection of ITPase-encoding potyvirid and secovirid in Mercurialis perennis: evidences for a convergent euphorbia-specific viral counterstrike. Virol J 2024; 21:6. [PMID: 38178191 PMCID: PMC10768138 DOI: 10.1186/s12985-023-02257-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 12/04/2023] [Indexed: 01/06/2024] Open
Abstract
BACKGROUND In cellular organisms, inosine triphosphate pyrophosphatases (ITPases) prevent the incorporation of mutagenic deaminated purines into nucleic acids. These enzymes have also been detected in the genomes of several plant RNA viruses infecting two euphorbia species. In particular, two ipomoviruses produce replicase-associated ITPases to cope with high concentration of non-canonical nucleotides found in cassava tissues. METHOD Using high-throughput RNA sequencing on the wild euphorbia species Mercurialis perennis, two new members of the families Potyviridae and Secoviridae were identified. Both viruses encode for a putative ITPase, and were found in mixed infection with a new partitivirid. Following biological and genomic characterization of these viruses, the origin and function of the phytoviral ITPases were investigated. RESULTS While the potyvirid was shown to be pathogenic, the secovirid and partitivirid could not be transmitted. The secovirid was found belonging to a proposed new Comovirinae genus tentatively named "Mercomovirus", which also accommodates other viruses identified through transcriptome mining, and for which an asymptomatic pollen-associated lifestyle is suspected. Homology and phylogenetic analyses inferred that the ITPases encoded by the potyvirid and secovirid were likely acquired through independent horizontal gene transfer events, forming lineages distinct from the enzymes found in cassava ipomoviruses. Possible origins from cellular organisms are discussed for these proteins. In parallel, the endogenous ITPase of M. perennis was predicted to encode for a C-terminal nuclear localization signal, which appears to be conserved among the ITPases of euphorbias but absent in other plant families. This subcellular localization is in line with the idea that nucleic acids remain protected in the nucleus, while deaminated nucleotides accumulate in the cytoplasm where they act as antiviral molecules. CONCLUSION Three new RNA viruses infecting M. perennis are described, two of which encoding for ITPases. These enzymes have distinct origins, and are likely required by viruses to circumvent high level of cytoplasmic non-canonical nucleotides. This putative plant defense mechanism has emerged early in the evolution of euphorbias, and seems to specifically target certain groups of RNA viruses infecting perennial hosts.
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Affiliation(s)
- Mathieu Mahillon
- Research Group Virology, Bacteriology and Phytoplasmology, Plant Protection Department, Agroscope, Nyon, Switzerland
| | - Justine Brodard
- Research Group Virology, Bacteriology and Phytoplasmology, Plant Protection Department, Agroscope, Nyon, Switzerland
| | - Nathalie Dubuis
- Research Group Virology, Bacteriology and Phytoplasmology, Plant Protection Department, Agroscope, Nyon, Switzerland
| | - Paul Gugerli
- Research Group Virology, Bacteriology and Phytoplasmology, Plant Protection Department, Agroscope, Nyon, Switzerland
| | - Arnaud G Blouin
- Research Group Virology, Bacteriology and Phytoplasmology, Plant Protection Department, Agroscope, Nyon, Switzerland
| | - Olivier Schumpp
- Research Group Virology, Bacteriology and Phytoplasmology, Plant Protection Department, Agroscope, Nyon, Switzerland.
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Zhang Q, Tretyakova N. Incorporation of inosine into DNA by human polymerase eta (Polη): kinetics of nucleotide misincorporation and structural basis for the mutagenicity. Biochem J 2023; 480:1479-1483. [PMID: 37746864 PMCID: PMC10586757 DOI: 10.1042/bcj20230159] [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: 08/04/2023] [Revised: 09/07/2023] [Accepted: 09/11/2023] [Indexed: 09/26/2023]
Abstract
Inosine, a purine nucleoside containing the hypoxanthine (HX) nucleobase, can form in DNA via hydrolytic deamination of adenine. Due to its structural similarity to guanine and the geometry of Watson-Crick base pairs, inosine can mispair with cytosine upon catalysis by DNA polymerases, leading to AT → GC mutations. Additionally, inosine plays an essential role in purine nucleotide biosynthesis, and inosine triphosphate is present in living cells. In a recent publication, Averill and Jung examined the possibility of polη catalyzed incorporation of deoxyinosine triphosphate (dITP) across dC and dT in a DNA template. They found that dITP can be incorporated across C or T, with the ratio of 13.7. X ray crystallography studies revealed that the mutagenic incorporation of dITP by human polη was affected by several factors including base pair geometry in the active site of the polymerase, tautomerization of nucleobases, and the interaction of the incoming dITP nucleotide with active site residues of polη. This study demonstrates that TLS incorporation of inosine monophosphate (IMP) into growing DNA chains contributes to its mutagenic potential in cells.
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Affiliation(s)
- Qi Zhang
- Department of Medicinal Chemistry, University of Minnesota-Twin Cities, Minneapolis, U.S.A
| | - Natalia Tretyakova
- Department of Medicinal Chemistry, University of Minnesota-Twin Cities, Minneapolis, U.S.A
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Schroader JH, Handley MT, Reddy K. Inosine triphosphate pyrophosphatase: A guardian of the cellular nucleotide pool and potential mediator of RNA function. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1790. [PMID: 37092460 DOI: 10.1002/wrna.1790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 02/10/2023] [Accepted: 03/20/2023] [Indexed: 04/25/2023]
Abstract
Inosine triphosphate pyrophosphatase (ITPase), encoded by the ITPA gene in humans, is an important enzyme that preserves the integrity of cellular nucleotide pools by hydrolyzing the noncanonical purine nucleotides (deoxy)inosine and (deoxy)xanthosine triphosphate into monophosphates and pyrophosphate. Variants in the ITPA gene can cause partial or complete ITPase deficiency. Partial ITPase deficiency is benign but clinically relevant as it is linked to altered drug responses. Complete ITPase deficiency causes a severe multisystem disorder characterized by seizures and encephalopathy that is frequently associated with fatal infantile dilated cardiomyopathy. In the absence of ITPase activity, its substrate noncanonical nucleotides have the potential to accumulate and become aberrantly incorporated into DNA and RNA. Hence, the pathophysiology of ITPase deficiency could arise from metabolic imbalance, altered DNA or RNA regulation, or from a combination of these factors. Here, we review the known functions of ITPase and highlight recent work aimed at determining the molecular basis for ITPA-associated pathogenesis which provides evidence for RNA dysfunction. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA in Disease and Development > RNA in Development.
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Affiliation(s)
- Jacob H Schroader
- The RNA Institute, University at Albany, State University of New York, Albany, New York, USA
- Department of Biological Sciences, University at Albany, State University of New York, Albany, New York, USA
| | - Mark T Handley
- Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Kaalak Reddy
- The RNA Institute, University at Albany, State University of New York, Albany, New York, USA
- Department of Biological Sciences, University at Albany, State University of New York, Albany, New York, USA
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Straube H, Straube J, Rinne J, Fischer L, Niehaus M, Witte CP, Herde M. An inosine triphosphate pyrophosphatase safeguards plant nucleic acids from aberrant purine nucleotides. THE NEW PHYTOLOGIST 2023; 237:1759-1775. [PMID: 36464781 DOI: 10.1111/nph.18656] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 11/22/2022] [Indexed: 06/17/2023]
Abstract
In plants, inosine is enzymatically introduced in some tRNAs, but not in other RNAs or DNA. Nonetheless, our data show that RNA and DNA from Arabidopsis thaliana contain (deoxy)inosine, probably derived from nonenzymatic adenosine deamination in nucleic acids and usage of (deoxy)inosine triphosphate (dITP and ITP) during nucleic acid synthesis. We combined biochemical approaches, LC-MS, as well as RNA-Seq to characterize a plant INOSINE TRIPHOSPHATE PYROPHOSPHATASE (ITPA) from A. thaliana, which is conserved in many organisms, and investigated the sources of deaminated purine nucleotides in plants. Inosine triphosphate pyrophosphatase dephosphorylates deaminated nucleoside di- and triphosphates to the respective monophosphates. ITPA loss-of-function causes inosine di- and triphosphate accumulation in vivo and an elevated inosine and deoxyinosine content in RNA and DNA, respectively, as well as salicylic acid (SA) accumulation, early senescence, and upregulation of transcripts associated with immunity and senescence. Cadmium-induced oxidative stress and biochemical inhibition of the INOSINE MONOPHOSPHATE DEHYDROGENASE leads to more IDP and ITP in the wild-type (WT), and this effect is enhanced in itpa mutants, suggesting that ITP originates from ATP deamination and IMP phosphorylation. Inosine triphosphate pyrophosphatase is part of a molecular protection system in plants, preventing the accumulation of (d)ITP and its usage for nucleic acid synthesis.
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Affiliation(s)
- Henryk Straube
- Department of Molecular Nutrition and Biochemistry of Plants, Leibniz Universität Hannover, Hannover, 30419, Germany
| | - Jannis Straube
- Department of Molecular Plant Breeding, Leibniz Universität Hannover, Hannover, 30419, Germany
| | - Jannis Rinne
- Department of Molecular Nutrition and Biochemistry of Plants, Leibniz Universität Hannover, Hannover, 30419, Germany
| | - Lisa Fischer
- Department of Molecular Nutrition and Biochemistry of Plants, Leibniz Universität Hannover, Hannover, 30419, Germany
| | - Markus Niehaus
- Department of Molecular Nutrition and Biochemistry of Plants, Leibniz Universität Hannover, Hannover, 30419, Germany
| | - Claus-Peter Witte
- Department of Molecular Nutrition and Biochemistry of Plants, Leibniz Universität Hannover, Hannover, 30419, Germany
| | - Marco Herde
- Department of Molecular Nutrition and Biochemistry of Plants, Leibniz Universität Hannover, Hannover, 30419, Germany
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