1
|
Thomas RC, Zaksauskaite R, Al-Kandari NY, Hyde AC, Abugable AA, El-Khamisy SF, van Eeden FJ. Second generation lethality in RNAseH2a knockout zebrafish. Nucleic Acids Res 2024:gkae725. [PMID: 39217460 DOI: 10.1093/nar/gkae725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 07/31/2024] [Accepted: 08/07/2024] [Indexed: 09/04/2024] Open
Abstract
Removal of ribonucleotides from DNA by RNaseH2 is essential for genome stability, and its impacted function causes the neurodegenerative disease, Aicardi Goutières Syndrome. We have created a zebrafish rnaseh2a mutant to model this process. Surprisingly, RNaseH2a knockouts show little phenotypic abnormality at adulthood in the first generation, unlike mouse knockout models, which are early embryonic lethal. However, the second generation offspring show reduced development, increased ribonucleotide incorporation and upregulation of key inflammatory markers, resulting in both maternal and paternal embryonic lethality. Thus, neither fathers or mothers can generate viable offspring even when crossed to wild-type partners. Despite their survival, rnaseh2a-/- adults show an accumulation of ribonucleotides in both the brain and testes that is not present in early development. Our data suggest that homozygotes possess RNaseH2 independent compensatory mechanisms that are inactive or overwhelmed by the inherited ribonucleotides in their offspring, or that zebrafish have a yet unknown tolerance mechanism. Additionally, we identify ribodysgenesis, the rapid removal of rNMPs and subsequently lethal fragmentation of DNA as responsible for maternal and paternal embryonic lethality.
Collapse
Affiliation(s)
- Ruth C Thomas
- Bateson Centre, School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
- Healthy Lifespan Institute, Sheffield Institute for Neuroscience, University of Sheffield, Sheffield S10 2TN, UK
| | - Ringaile Zaksauskaite
- Bateson Centre, School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
- Healthy Lifespan Institute, Sheffield Institute for Neuroscience, University of Sheffield, Sheffield S10 2TN, UK
| | - Norah Y Al-Kandari
- Bateson Centre, School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
- Healthy Lifespan Institute, Sheffield Institute for Neuroscience, University of Sheffield, Sheffield S10 2TN, UK
| | - Anne Cathrine Hyde
- Bateson Centre, School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
- Healthy Lifespan Institute, Sheffield Institute for Neuroscience, University of Sheffield, Sheffield S10 2TN, UK
| | - Arwa A Abugable
- Healthy Lifespan Institute, Sheffield Institute for Neuroscience, University of Sheffield, Sheffield S10 2TN, UK
| | - Sherif F El-Khamisy
- Bateson Centre, School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
- Healthy Lifespan Institute, Sheffield Institute for Neuroscience, University of Sheffield, Sheffield S10 2TN, UK
- The Institute of Cancer Therapeutics, University of Bradford, BD7 1DP, UK
| | - Freek J van Eeden
- Bateson Centre, School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
- Healthy Lifespan Institute, Sheffield Institute for Neuroscience, University of Sheffield, Sheffield S10 2TN, UK
| |
Collapse
|
2
|
Kundnani DL, Yang T, Gombolay AL, Mukherjee K, Newnam G, Meers C, Verma I, Chhatlani K, Mehta ZH, Mouawad C, Storici F. Distinct features of ribonucleotides within genomic DNA in Aicardi-Goutières syndrome ortholog mutants of Saccharomyces cerevisiae. iScience 2024; 27:110012. [PMID: 38868188 PMCID: PMC11166700 DOI: 10.1016/j.isci.2024.110012] [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: 10/02/2023] [Revised: 03/15/2024] [Accepted: 05/14/2024] [Indexed: 06/14/2024] Open
Abstract
Ribonucleoside monophosphates (rNMPs) are abundantly found within genomic DNA of cells. The embedded rNMPs alter DNA properties and impact genome stability. Mutations in ribonuclease (RNase) H2, a key enzyme for rNMP removal, are associated with the Aicardi-Goutières syndrome (AGS), a severe neurological disorder. Here, we engineered orthologs of the human RNASEH2A-G37S and RNASEH2C-R69W AGS mutations in yeast Saccharomyces cerevisiae: rnh201-G42S and rnh203-K46W. Using the ribose-seq technique and the Ribose-Map bioinformatics toolkit, we unveiled rNMP abundance, composition, hotspots, and sequence context in these AGS-ortholog mutants. We found a high rNMP presence in the nuclear genome of rnh201-G42S-mutant cells, and an elevated rCMP content in both mutants, reflecting preferential cleavage of RNase H2 at rGMP. We discovered unique rNMP patterns in each mutant, showing differential activity of the AGS mutants on the leading or lagging replication strands. This study guides future research on rNMP characteristics in human genomes with AGS mutations.
Collapse
Affiliation(s)
- Deepali L. Kundnani
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Taehwan Yang
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Alli L. Gombolay
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
- Bacterial Special Pathogens Branch, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA
| | - Kuntal Mukherjee
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Gary Newnam
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Chance Meers
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Ishika Verma
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Kirti Chhatlani
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Zeel H. Mehta
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Celine Mouawad
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Francesca Storici
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| |
Collapse
|
3
|
Raducanu VS, Tehseen M, Al-Amodi A, Joudeh LI, De Biasio A, Hamdan SM. Mechanistic investigation of human maturation of Okazaki fragments reveals slow kinetics. Nat Commun 2022; 13:6973. [PMID: 36379932 PMCID: PMC9666535 DOI: 10.1038/s41467-022-34751-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Accepted: 11/04/2022] [Indexed: 11/16/2022] Open
Abstract
The final steps of lagging strand synthesis induce maturation of Okazaki fragments via removal of the RNA primers and ligation. Iterative cycles between Polymerase δ (Polδ) and Flap endonuclease-1 (FEN1) remove the primer, with an intermediary nick structure generated for each cycle. Here, we show that human Polδ is inefficient in releasing the nick product from FEN1, resulting in non-processive and remarkably slow RNA removal. Ligase 1 (Lig1) can release the nick from FEN1 and actively drive the reaction toward ligation. These mechanisms are coordinated by PCNA, which encircles DNA, and dynamically recruits Polδ, FEN1, and Lig1 to compete for their substrates. Our findings call for investigating additional pathways that may accelerate RNA removal in human cells, such as RNA pre-removal by RNase Hs, which, as demonstrated herein, enhances the maturation rate ~10-fold. They also suggest that FEN1 may attenuate the various activities of Polδ during DNA repair and recombination.
Collapse
Affiliation(s)
- Vlad-Stefan Raducanu
- Bioscience Program, Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955, Saudi Arabia
| | - Muhammad Tehseen
- Bioscience Program, Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955, Saudi Arabia
| | - Amani Al-Amodi
- Bioscience Program, Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955, Saudi Arabia
| | - Luay I Joudeh
- Bioscience Program, Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955, Saudi Arabia
| | - Alfredo De Biasio
- Bioscience Program, Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955, Saudi Arabia.
| | - Samir M Hamdan
- Bioscience Program, Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955, Saudi Arabia.
| |
Collapse
|
4
|
Kandabashi M, Yano H, Hara H, Ogawa S, Kamoda K, Ishibashi S, Himeda K, Baba M, Takita T, Yasukawa K. Analysis of ribonucleotide content in the genomic DNA of ribonuclease H2 A subunit (RH2A)-knockout NIH3T3 cells after transient expression of wild-type RH2A or RH2A variants with an Aicardi-Goutières syndrome-causing mutation. J Biochem 2022; 172:225-231. [DOI: 10.1093/jb/mvac056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 07/03/2022] [Indexed: 11/13/2022] Open
Abstract
Summary
Ribonuclease (RNase) H2 is involved in the removal of ribonucleotides embedded in genomic DNA. Eukaryotic RNase H2 is a heterotrimer consisting of the catalytic A subunit (RH2A) and the accessory B and C subunits. This study aimed to compare the cellular activities of wild-type ribonuclease (RNase) H2 and its variants with a mutation causing neuroinflammatory autoimmune disease, Aicardi-Goutières syndrome (AGS). We first analyzed cellular RNase H2 activity and ribonucleotide content in the genomic DNA of RH2A-knockout (KO) mouse fibroblast NIH3T3 cells after transfection with a transient expression plasmid encoding mouse wild-type RH2A. From four hours after transfection, the RNase H2 activity increased, and the amount of ribonucleotides decreased, as compared with the corresponding non-transfected RH2A-KO cells. This demonstrated the rapidness of ribonucleotide turnover in mammalian genomic DNA and the importance of continuous expression of RNase H2 to maintain the ribonucleotide amount low. Next, we expressed mouse RH2A variants with a mutation corresponding to a human AGS-causing mutation in RH2A-KO NIH3T3 cells. Neither increase in RNase H2 activity nor decrease in ribonucleotide amount were observed for G37S; however, both conditions were observed for N213I and R293H. This corresponded with our previous results on the activity of recombinant human RNase H2 variants.
Collapse
Affiliation(s)
- Mako Kandabashi
- Graduate School of Agriculture Division of Food Science and Biotechnology, , Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Haruna Yano
- Graduate School of Agriculture Division of Food Science and Biotechnology, , Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Haruka Hara
- Graduate School of Agriculture Division of Food Science and Biotechnology, , Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Saori Ogawa
- Graduate School of Agriculture Division of Food Science and Biotechnology, , Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Kana Kamoda
- Graduate School of Agriculture Division of Food Science and Biotechnology, , Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Shu Ishibashi
- Graduate School of Agriculture Division of Food Science and Biotechnology, , Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Kohei Himeda
- Graduate School of Agriculture Division of Food Science and Biotechnology, , Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Misato Baba
- Graduate School of Agriculture Division of Food Science and Biotechnology, , Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Teisuke Takita
- Graduate School of Agriculture Division of Food Science and Biotechnology, , Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Kiyoshi Yasukawa
- Graduate School of Agriculture Division of Food Science and Biotechnology, , Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| |
Collapse
|
5
|
Baba M, Kojima K, Nishimura T, Sugiura T, Takita T, Uehara R, Crouch RJ, Yasukawa K. Val143 of human ribonuclease H2 is not critical for, but plays a role in determining catalytic activity and substrate specificity. PLoS One 2020; 15:e0228774. [PMID: 32069311 PMCID: PMC7028304 DOI: 10.1371/journal.pone.0228774] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 01/22/2020] [Indexed: 11/18/2022] Open
Abstract
Ribonuclease H2 (RNase H2) exhibits both single ribonucleotide excision activity (activity A) and RNA strand degrading activity (activity B). Val143 of human RNase H2 is located at the active site and is conserved in eukaryotic RNase H2. In this study, we explored the role of Val143 in catalytic activity and substrate specificity. Nineteen single variants at amino acid position 143 were expressed in E. coli, and all variants except for V143C and V143M were purified from the cells. When the activity of the wild-type human RNase H2 (WT) was set as 100%, the relative activities A and B of the 17 variants were in the range of 0.05–130 and 0.02–42%, respectively. When the ratio of the relative activity A to the relative activity B of WT was set as 1, the ratios of the 17 variants were in the range of 0.2–5.7. This indicates that valine is optimal for balancing the two activities. The ratios for V143Y and V143W were relatively high (5.6 and 5.5, respectively), suggesting that the bulky residues like tyrosine and tryptophan at position 143 caused steric hindrance with the 2’-OH of the sugar moiety of the ribonucleotide at the 5’ side of the scissile phosphodiester bond. The ratio for V143Q was relatively low (0.2). These results suggested that Val143 is not critical for, but plays a role in determining catalytic activity and substrate specificity.
Collapse
Affiliation(s)
- Misato Baba
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Kenji Kojima
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Takuto Nishimura
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Takuya Sugiura
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Teisuke Takita
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Ryo Uehara
- Section on Formation of RNA, Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States of America
- Ritsumeikan Global Innovation Research Organization, Ritsumeikan University, Noji-higashi, Shiga, Japan
| | - Robert J. Crouch
- Section on Formation of RNA, Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States of America
| | - Kiyoshi Yasukawa
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
- * E-mail:
| |
Collapse
|
6
|
Nishimura T, Baba M, Ogawa S, Kojima K, Takita T, Crouch RJ, Yasukawa K. Characterization of six recombinant human RNase H2 bearing Aicardi-Goutiéres syndrome causing mutations. J Biochem 2019; 166:537-545. [PMID: 31529068 DOI: 10.1093/jb/mvz073] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 09/02/2019] [Indexed: 01/18/2023] Open
Abstract
Mammalian RNase H2 is a heterotrimeric enzyme consisting of one catalytic subunit (A) and two accessory subunits (B and C). RNase H2 is involved in the removal of a single ribonucleotide embedded in genomic DNA and removal of RNA of RNA/DNA hybrids. In humans, mutation of the RNase H2 gene causes a severe neuroinflammatory disorder Aicardi-Goutières syndrome (AGS). Here, we examined the activity and stability of six recombinant human RNase H2 variants bearing one AGS-causing mutation, A-G37S (Gly37 in the A subunit is replaced with Ser), A-N212I, A-R291H, B-A177T, B-V185G, or C-R69W. The activity of A-G37S was 0.3-1% of that of the wild-type RNase H2 (WT), while those of other five variants were 51-120%. In circular dichroism measurement, the melting temperatures of variants were 50-53°C, lower than that of WT (56°C). These results suggested that A-G37S had decreased activity and stability than WT, while other five variants had decreased stability but retained activity. In gel filtration chromatography of the purified enzyme preparation, WT migrated as a heterotrimer, while A-R291H eluted in two separate peaks containing either the heterotrimer or only the A subunit, suggesting that some AGS-causing mutations affect the heterotrimer-forming stability of RNase H2.
Collapse
Affiliation(s)
- Takuto Nishimura
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Oiwakecho, Kitashirakawa, Sakyoku, Kyoto 606-8502, Japan
| | - Misato Baba
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Oiwakecho, Kitashirakawa, Sakyoku, Kyoto 606-8502, Japan
| | - Saori Ogawa
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Oiwakecho, Kitashirakawa, Sakyoku, Kyoto 606-8502, Japan
| | - Kenji Kojima
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Oiwakecho, Kitashirakawa, Sakyoku, Kyoto 606-8502, Japan
| | - Teisuke Takita
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Oiwakecho, Kitashirakawa, Sakyoku, Kyoto 606-8502, Japan
| | - Robert J Crouch
- Section on Formation of RNA, Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kiyoshi Yasukawa
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Oiwakecho, Kitashirakawa, Sakyoku, Kyoto 606-8502, Japan
| |
Collapse
|
7
|
Uehara R, Cerritelli SM, Hasin N, Sakhuja K, London M, Iranzo J, Chon H, Grinberg A, Crouch RJ. Two RNase H2 Mutants with Differential rNMP Processing Activity Reveal a Threshold of Ribonucleotide Tolerance for Embryonic Development. Cell Rep 2019; 25:1135-1145.e5. [PMID: 30380406 PMCID: PMC6309994 DOI: 10.1016/j.celrep.2018.10.019] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 09/18/2018] [Accepted: 10/03/2018] [Indexed: 11/30/2022] Open
Abstract
RNase H2 has two distinct functions: initiation of the ribonucleotide excision repair (RER) pathway by cleaving ribonucleotides (rNMPs) incorporated during DNA replication and processing the RNA portion of an R-loop formed during transcription. An RNase H2 mutant lacking RER activity but supporting R-loop removal revealed that rNMPs in DNA initiate p53-dependent DNA damage response and early embryonic arrest in mouse. However, an RNase H2 AGS-related mutant with residual RER activity develops to birth. Estimations of the number of rNMPs in DNA in these two mutants define a ribonucleotide threshold above which p53 induces apoptosis. Below the threshold, rNMPs in DNA trigger an innate immune response. Compound heterozygous cells, containing both defective enzymes, retain rNMPs above the threshold, indicative of competition for RER substrates between active and inactive enzymes, suggesting that patients with compound heterozygous mutations in RNASEH2 genes may not reflect the properties of recombinantly expressed proteins. Uehara et al. use RNase H2 mice with differing activity levels for removal of rNMPs embedded in DNA. Moderate levels of rNMPs lead to perinatal lethality activating the cGAS-Sting DNA sensing innate immune response. Exceeding a threshold, high abundance of rNMPs activates p53-dependent DNA damage, causing early embryonic lethality.
Collapse
Affiliation(s)
- Ryo Uehara
- SFR, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD, USA
| | - Susana M Cerritelli
- SFR, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD, USA
| | - Naushaba Hasin
- SFR, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD, USA
| | - Kiran Sakhuja
- SFR, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD, USA
| | - Mariya London
- SFR, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD, USA
| | - Jaime Iranzo
- NCBI, National Library of Medicine, Bethesda, MD, USA
| | - Hyongi Chon
- SFR, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD, USA
| | - Alexander Grinberg
- Mouse Core, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD, USA
| | - Robert J Crouch
- SFR, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD, USA.
| |
Collapse
|
8
|
Cerritelli SM, Crouch RJ. RNase H2-RED carpets the path to eukaryotic RNase H2 functions. DNA Repair (Amst) 2019; 84:102736. [PMID: 31761672 PMCID: PMC6936605 DOI: 10.1016/j.dnarep.2019.102736] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 10/15/2019] [Indexed: 11/24/2022]
Abstract
Eukaryotic RNases H2 have dual functions in initiating the removal of ribonucleoside monophosphates (rNMPs) incorporated by DNA polymerases during DNA synthesis and in cleaving the RNA moiety of RNA/DNA hybrids formed during transcription and retrotransposition. The other major cellular RNase H, RNase H1, shares the hybrid processing activity, but not all substrates. After RNase H2 incision at the rNMPs in DNA the Ribonucleotide Excision Repair (RER) pathway completes the removal, restoring dsDNA. The development of the RNase H2-RED (Ribonucleotide Excision Defective) mutant enzyme, which can process RNA/DNA hybrids but is unable to cleave rNMPs embedded in DNA has unlinked the two activities and illuminated the roles of RNase H2 in cellular metabolism. Studies mostly in Saccharomyces cerevisiae, have shown both activities of RNase H2 are necessary to maintain genome integrity and that RNase H1 and H2 have overlapping as well as distinct RNA/DNA hybrid substrates. In mouse RNase H2-RED confirmed that rNMPs in DNA during embryogenesis induce lethality in a p53-dependent DNA damage response. In mammalian cell cultures, RNase H2-RED helped identifying DNA lesions produced by Top1 cleavage at rNMPs and led to determine that RNase H2 participates in the retrotransposition of LINE-1 elements. In this review, we summarize the studies and conclusions reached by utilization of RNase H2-RED enzyme in different model systems.
Collapse
Affiliation(s)
- Susana M Cerritelli
- SFR, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Robert J Crouch
- SFR, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.
| |
Collapse
|
9
|
Tsukiashi M, Baba M, Kojima K, Himeda K, Takita T, Yasukawa K. Construction and characterization of ribonuclease H2 knockout NIH3T3 cells. J Biochem 2019; 165:249-256. [PMID: 30481312 DOI: 10.1093/jb/mvy101] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2018] [Accepted: 11/13/2018] [Indexed: 11/13/2022] Open
Abstract
Ribonuclease H (RNase H) specifically hydrolyzes the 5'-phosphodiester bonds of the RNA of RNA/DNA hybrid. Both types 1 and 2 RNases H act on the RNA strand of the hybrid, while only type 2 acts on the single ribonucleotide embedded in DNA duplex. In this study, to explore the role of mammalian type 2 RNase H (RNase H2) in cells, we constructed the RNase H2 knockout NIH3T3 cells (KO cells) by CRISPR/Cas9 system. KO cells hydrolyzed RNA strands in RNA/DNA hybrid, but not single ribonucleotides in DNA duplex, while wild-type NIH3T3 cells (WT cells) hydrolyzed both. Genomic DNA in the KO cells was more heavily hydrolyzed than in the WT cells by the alkaline or RNase H2 treatment, suggesting that the KO cells contained more ribonucleotides in genomic DNA than the WT cells. The growth rate of the KO cells was 60% of that of the WT cells. Expression of interferon-stimulated genes (ISGs) in the KO cells was not markedly elevated compared with the WT cells. These results suggest that in NIH3T3 cells, RNase H2 is crucial for suppressing the accumulation of ribonucleotides in genomic DNA but not for the expression of ISGs.
Collapse
Affiliation(s)
- Motoki Tsukiashi
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Misato Baba
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Kenji Kojima
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Kohei Himeda
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Teisuke Takita
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Kiyoshi Yasukawa
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, Japan
| |
Collapse
|
10
|
Shapson-Coe A, Valeiras B, Wall C, Rada C. Aicardi-Goutières Syndrome associated mutations of RNase H2B impair its interaction with ZMYM3 and the CoREST histone-modifying complex. PLoS One 2019; 14:e0213553. [PMID: 30889214 PMCID: PMC6424451 DOI: 10.1371/journal.pone.0213553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 02/24/2019] [Indexed: 11/18/2022] Open
Abstract
DNA-RNA hybrids arise in all cell types, and are removed by multiple enzymes, including the trimeric ribonuclease, RNase H2. Mutations in human RNase H2 result in Aicardi–Goutières syndrome (AGS), an inflammatory brain disorder notable for being a Mendelian mimic of congenital viral infection. Previous studies have shown that several AGS-associated mutations of the RNase H2B subunit do not affect trimer stability or catalytic activity and are clustered on the surface of the complex, leading us to speculate that these mutations might impair important interactions of RNase H2 with so far unidentified proteins. In this study, we show that AGS mutations in this cluster impair the interaction of RNase H2 with several members of the CoREST chromatin-silencing complex that include the histone deacetylase HDAC2 and the demethylase KDM1A, the transcriptional regulators RCOR1 and GTFII-I as well as ZMYM3, an MYM-type zinc finger protein. We also show that the interaction is mediated by the zinc finger protein ZMYM3, suggesting that ZMYM3 acts as a novel type of scaffold protein coordinating interactions between deacetylase, demethylase and RNase H type enzymes, raising the question of whether coordination between histone modifications and the degradation of RNA-DNA hybrids may be required to prevent inflammation in humans.
Collapse
Affiliation(s)
- Alexander Shapson-Coe
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, United Kingdom
- * E-mail: (ASC); (CR)
| | - Brenda Valeiras
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, United Kingdom
| | - Christopher Wall
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, United Kingdom
| | - Cristina Rada
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, United Kingdom
- * E-mail: (ASC); (CR)
| |
Collapse
|
11
|
Tripathi R, Noetzel J, Marx D. Exposing catalytic versatility of GTPases: taking reaction detours in mutants of hGBP1 enzyme without additional energetic cost. Phys Chem Chem Phys 2019; 21:859-867. [DOI: 10.1039/c8cp06343e] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Our study reveals that the replacement of catalytically competent residues by the inert amino acid alanine, S73A and E99A, in hGBP1 opens a plethora of molecularly different reaction pathways featuring very similar energy barriers as the wild type.
Collapse
Affiliation(s)
- Ravi Tripathi
- Lehrstuhl für Theoretische Chemie
- Ruhr-Universität Bochum
- 44780 Bochum
- Germany
| | - Jan Noetzel
- Lehrstuhl für Theoretische Chemie
- Ruhr-Universität Bochum
- 44780 Bochum
- Germany
| | - Dominik Marx
- Lehrstuhl für Theoretische Chemie
- Ruhr-Universität Bochum
- 44780 Bochum
- Germany
| |
Collapse
|
12
|
Fu I, Smith DJ, Broyde S. Rotational and translational positions determine the structural and dynamic impact of a single ribonucleotide incorporated in the nucleosome. DNA Repair (Amst) 2018; 73:155-163. [PMID: 30522887 DOI: 10.1016/j.dnarep.2018.11.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 11/26/2018] [Accepted: 11/28/2018] [Indexed: 12/13/2022]
Abstract
Ribonucleotides misincorporated by replicative DNA polymerases are by far the most common DNA lesion. The presence of ribonucleotides in DNA is associated with genome instability, causing replication stress, chromosome fragility, gross chromosomal rearrangements, and other mutagenic events. Furthermore, nucleosome and chromatin assembly as well as nucleosome positioning are affected by the presence of ribonucleotides. Notably, nucleosome formation is significantly reduced by a single ribonucleotide. Single ribonucleotides are primarily removed from DNA by the ribonucleotide excision repair (RER) pathway via the RNase H2 enzyme, which incises the DNA backbone on the 5'-side of the ribonucleotide. While the structural implications of a single ribonucleotide in free duplex DNA have been well studied, how a single ribonucleotide embedded in nucleosomal DNA impacts nucleosome structure and dynamics, and the possible consequent impact on RER, have not been explored. We have carried out 3.5 μs molecular dynamics simulations of a single ribonucleotide incorporated at various translational and rotational positions in a nucleosome core particle. We find that the presence of the 2'-OH group on the ribose impacts the local conformation and dynamics of both the ribonucleotide and nearby DNA nucleotides as well as their interactions with histones; the nature of these disturbances depends on the rotational and translational setting, including whether the ribose faces toward or away from the histones. The ribonucleotide's preferred C3'-endo pucker is stabilized by interactions with the histones, and furthermore the ribonucleotide can cause dynamic local duplex disturbance involving an abnormal C3'-endo population of the adjacent deoxyribose pucker, minor groove opening, ruptured Watson-Crick pairing, and duplex unwinding that are governed by translation-dependent histone-nucleotide interactions. Possible effects of these disturbances on RER are considered.
Collapse
Affiliation(s)
- Iwen Fu
- Department of Biology, New York University, 100 Washington Square East, New York, NY, 10003, United States.
| | - Duncan J Smith
- Department of Biology, New York University, 100 Washington Square East, New York, NY, 10003, United States.
| | - Suse Broyde
- Department of Biology, New York University, 100 Washington Square East, New York, NY, 10003, United States.
| |
Collapse
|
13
|
Matz KM, Guzman RM, Goodman AG. The Role of Nucleic Acid Sensing in Controlling Microbial and Autoimmune Disorders. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2018; 345:35-136. [PMID: 30904196 PMCID: PMC6445394 DOI: 10.1016/bs.ircmb.2018.08.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Innate immunity, the first line of defense against invading pathogens, is an ancient form of host defense found in all animals, from sponges to humans. During infection, innate immune receptors recognize conserved molecular patterns, such as microbial surface molecules, metabolites produces during infection, or nucleic acids of the microbe's genome. When initiated, the innate immune response activates a host defense program that leads to the synthesis proteins capable of pathogen killing. In mammals, the induction of cytokines during the innate immune response leads to the recruitment of professional immune cells to the site of infection, leading to an adaptive immune response. While a fully functional innate immune response is crucial for a proper host response and curbing microbial infection, if the innate immune response is dysfunctional and is activated in the absence of infection, autoinflammation and autoimmune disorders can develop. Therefore, it follows that the innate immune response must be tightly controlled to avoid an autoimmune response from host-derived molecules, yet still unencumbered to respond to infection. In this review, we will focus on the innate immune response activated from cytosolic nucleic acids, derived from the microbe or host itself. We will depict how viruses and bacteria activate these nucleic acid sensing pathways and their mechanisms to inhibit the pathways. We will also describe the autoinflammatory and autoimmune disorders that develop when these pathways are hyperactive. Finally, we will discuss gaps in knowledge with regard to innate immune response failure and identify where further research is needed.
Collapse
Affiliation(s)
- Keesha M Matz
- School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, WA, United States
| | - R Marena Guzman
- School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, WA, United States
| | - Alan G Goodman
- School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, WA, United States; Paul G. Allen School for Global Animal Health, College of Veterinary Medicine, Washington State University, Pullman, WA, United States.
| |
Collapse
|
14
|
Kojima K, Baba M, Tsukiashi M, Nishimura T, Yasukawa K. RNA/DNA structures recognized by RNase H2. Brief Funct Genomics 2018; 18:169-173. [DOI: 10.1093/bfgp/ely024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Abstract
Ribonuclease H (RNase H) [EC 3.1.26.4] is an enzyme that specifically degrades RNA from RNA/DNA hybrids. Since its discovery in 1969, the enzyme has been extensively studied for its catalytic mechanism and physiological role. RNase H has been classified into two major families, Type 1 and Type 2. Type 1 enzymes are designated RNase HI in prokaryotes and RNase H1 in eukaryotes, while Type 2 enzymes are designated RNase HII in prokaryotes and RNase H2 in eukaryotes. Type 2 enzymes are able to cleave the 5′-phosphodiester bond of one ribonucleotide embedded in a DNA double strand. Recent studies have shown that RNase H2 is involved in excision of a single ribonucleotide embedded in genomic DNA and removal of an R-loop formed in cells. It is also involved in double-strand break of DNA and its repair. In this review, we aim to outline the structures recognized by RNase H2.
Collapse
Affiliation(s)
- Kenji Kojima
- Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Misato Baba
- Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | | | | | | |
Collapse
|
15
|
Orebaugh CD, Lujan SA, Burkholder AB, Clausen AR, Kunkel TA. Mapping Ribonucleotides Incorporated into DNA by Hydrolytic End-Sequencing. Methods Mol Biol 2018; 1672:329-345. [PMID: 29043634 DOI: 10.1007/978-1-4939-7306-4_23] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Ribonucleotides embedded within DNA render the DNA sensitive to the formation of single-stranded breaks under alkali conditions. Here, we describe a next-generation sequencing method called hydrolytic end sequencing (HydEn-seq) to map ribonucleotides inserted into the genome of Saccharomyce cerevisiae strains deficient in ribonucleotide excision repair. We use this method to map several genomic features in wild-type and replicase variant yeast strains.
Collapse
Affiliation(s)
- Clinton D Orebaugh
- Genome Integrity and Structural Biology Laboratory, National Institute for Environmental Health Sciences, National Institute of Health (NIH), 111 TW Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Scott A Lujan
- Genome Integrity and Structural Biology Laboratory, National Institute for Environmental Health Sciences, National Institute of Health (NIH), 111 TW Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Adam B Burkholder
- Integrative Bioinformatics, National Institute for Environmental Health Sciences, National Institute of Health (NIH), Research Triangle Park, NC, USA
| | - Anders R Clausen
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg, Sweden
| | - Thomas A Kunkel
- Genome Integrity and Structural Biology Laboratory, National Institute for Environmental Health Sciences, National Institute of Health (NIH), 111 TW Alexander Drive, Research Triangle Park, NC, 27709, USA.
| |
Collapse
|
16
|
Suarez NA, Macia A, Muotri AR. LINE-1 retrotransposons in healthy and diseased human brain. Dev Neurobiol 2017; 78:434-455. [PMID: 29239145 DOI: 10.1002/dneu.22567] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 12/07/2017] [Accepted: 12/08/2017] [Indexed: 12/12/2022]
Abstract
Long interspersed element-1 (LINE-1 or L1) is a transposable element with the ability to self-mobilize throughout the human genome. The L1 elements found in the human brain is hypothesized to date back 56 million years ago and has survived evolution, currently accounting for 17% of the human genome. L1 retrotransposition has been theorized to contribute to somatic mosaicism. This review focuses on the presence of L1 in the healthy and diseased human brain, such as in autism spectrum disorders. Throughout this exploration, we will discuss the impact L1 has on neurological disorders that can occur throughout the human lifetime. With this, we hope to better understand the complex role of L1 in the human brain development and its implications to human cognition. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 78: 434-455, 2018.
Collapse
Affiliation(s)
- Nicole A Suarez
- Department of Pediatrics/Rady Children's Hospital San Diego, University of California San Diego, La Jolla, California, 92093
| | - Angela Macia
- Department of Pediatrics/Rady Children's Hospital San Diego, University of California San Diego, La Jolla, California, 92093
| | - Alysson R Muotri
- Department of Pediatrics/Rady Children's Hospital San Diego, University of California San Diego, La Jolla, California, 92093
| |
Collapse
|
17
|
Boddy AM, Harrison PW, Montgomery SH, Caravas JA, Raghanti MA, Phillips KA, Mundy NI, Wildman DE. Evidence of a Conserved Molecular Response to Selection for Increased Brain Size in Primates. Genome Biol Evol 2017; 9:700-713. [PMID: 28391320 PMCID: PMC5381557 DOI: 10.1093/gbe/evx028] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/23/2017] [Indexed: 12/12/2022] Open
Abstract
The adaptive significance of human brain evolution has been frequently studied through comparisons with other primates. However, the evolution of increased brain size is not restricted to the human lineage but is a general characteristic of primate evolution. Whether or not these independent episodes of increased brain size share a common genetic basis is unclear. We sequenced and de novo assembled the transcriptome from the neocortical tissue of the most highly encephalized nonhuman primate, the tufted capuchin monkey (Cebus apella). Using this novel data set, we conducted a genome-wide analysis of orthologous brain-expressed protein coding genes to identify evidence of conserved gene–phenotype associations and species-specific adaptations during three independent episodes of brain size increase. We identify a greater number of genes associated with either total brain mass or relative brain size across these six species than show species-specific accelerated rates of evolution in individual large-brained lineages. We test the robustness of these associations in an expanded data set of 13 species, through permutation tests and by analyzing how genome-wide patterns of substitution co-vary with brain size. Many of the genes targeted by selection during brain expansion have glutamatergic functions or roles in cell cycle dynamics. We also identify accelerated evolution in a number of individual capuchin genes whose human orthologs are associated with human neuropsychiatric disorders. These findings demonstrate the value of phenotypically informed genome analyses, and suggest at least some aspects of human brain evolution have occurred through conserved gene–phenotype associations. Understanding these commonalities is essential for distinguishing human-specific selection events from general trends in brain evolution.
Collapse
Affiliation(s)
- Amy M Boddy
- The Biodesign Institute, Arizona State University, Tempe, AZ.,Wayne State University School of Medicine, Center for Molecular Medicine and Genetics, Detroit, Michigan, Detroit, MI
| | - Peter W Harrison
- Department of Genetics Evolution & Environment, University College London, United Kingdom.,European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Stephen H Montgomery
- Department of Genetics Evolution & Environment, University College London, United Kingdom.,Department of Zoology, University of Cambridge, United Kingdom
| | - Jason A Caravas
- Wayne State University School of Medicine, Center for Molecular Medicine and Genetics, Detroit, Michigan, Detroit, MI
| | - Mary Ann Raghanti
- Department of Anthropology and School of Biomedical Sciences, Kent State University, Kent, OH
| | | | | | - Derek E Wildman
- Wayne State University School of Medicine, Center for Molecular Medicine and Genetics, Detroit, Michigan, Detroit, MI.,Department of Molecular & Integrative Physiology, University of Illinois, Urbana-Champaign, Urbana, IL.,Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana-Champaign, Urbana, IL
| |
Collapse
|
18
|
Baba M, Kojima K, Nakase R, Imai S, Yamasaki T, Takita T, Crouch RJ, Yasukawa K. Effects of neutral salts and pH on the activity and stability of human RNase H2. J Biochem 2017; 162:211-219. [PMID: 28402412 DOI: 10.1093/jb/mvx021] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 02/13/2017] [Indexed: 11/14/2022] Open
Abstract
Ribonuclease H (RNase H) specifically degrades the RNA of RNA/DNA hybrid. Recent study has shown that a single ribonucleotide is embedded in DNA double strand at every few thousand base pairs in human genome, and human RNase H2 is involved in its removal. Here, we examined the effects of neutral salts and pH on the activity and stability of human RNase H2. NaCl, KCl, RbCl and NaBr increased the activity to 170-390% at 10-60 mM, while LiCl, LiBr and CsCl inhibited it, suggesting that species of cation, but not anion, is responsible for the effect on activity. NaCl and KCl increased the stability by decreasing the first-order rate constant of the inactivation to 50-60% at 60-80 mM. The activity at 25-35 °C exhibited a narrow bell-shaped pH-dependence with the acidic and alkaline pKe (pKe1 and pKe2) values of 7.3 - 7.6 and 8.1 - 8.8, respectively. Enthalpy changes (ΔH°) of deprotonation were 5 ± 21 kJ mol-1 for pKe1 and 68 ± 25 kJ mol-1 for pKe2. These results suggest that the ionizable groups responsible for pKe1 may be two out of Asp34, Glu35 and Asp141 of DEDD motif, and that for pKe2 may be Lys69 of DSK motif.
Collapse
Affiliation(s)
- Misato Baba
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Oiwakecho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan
| | - Kenji Kojima
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Oiwakecho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan
| | - Rihoko Nakase
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Oiwakecho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan
| | - Shota Imai
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Oiwakecho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan
| | - Tomomi Yamasaki
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Oiwakecho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan
| | - Teisuke Takita
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Oiwakecho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan
| | - Robert J Crouch
- Section on Formation of RNA, Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kiyoshi Yasukawa
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Oiwakecho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan
| |
Collapse
|
19
|
Pokatayev V, Hasin N, Chon H, Cerritelli SM, Sakhuja K, Ward JM, Morris HD, Yan N, Crouch RJ. RNase H2 catalytic core Aicardi-Goutières syndrome-related mutant invokes cGAS-STING innate immune-sensing pathway in mice. J Exp Med 2016; 213:329-36. [PMID: 26880576 PMCID: PMC4813680 DOI: 10.1084/jem.20151464] [Citation(s) in RCA: 174] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 01/25/2016] [Indexed: 11/25/2022] Open
Abstract
Mice with a mutated form of RNase H2 found in patients with the neuroinflammatory
Aicardi-Goutières Syndrome develop a lethal, cGAS–STING–dependent
disease. The neuroinflammatory autoimmune disease Aicardi-Goutières syndrome (AGS)
develops from mutations in genes encoding several nucleotide-processing proteins,
including RNase H2. Defective RNase H2 may induce accumulation of self-nucleic acid
species that trigger chronic type I interferon and inflammatory responses, leading to
AGS pathology. We created a knock-in mouse model with an RNase H2 AGS mutation in a
highly conserved residue of the catalytic subunit,
Rnaseh2aG37S/G37S (G37S), to understand disease
pathology. G37S homozygotes are perinatal lethal, in contrast to the early embryonic
lethality previously reported for Rnaseh2b- or Rnaseh2c-null mice.
Importantly, we found that the G37S mutation led to increased expression of
interferon-stimulated genes dependent on the cGAS–STING signaling pathway.
Ablation of STING in the G37S mice results in partial rescue of the perinatal
lethality, with viable mice exhibiting white spotting on their ventral surface. We
believe that the G37S knock-in mouse provides an excellent animal model for studying
RNASEH2-associated autoimmune diseases.
Collapse
Affiliation(s)
- Vladislav Pokatayev
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390 Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Naushaba Hasin
- Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892
| | - Hyongi Chon
- Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892
| | - Susana M Cerritelli
- Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892
| | - Kiran Sakhuja
- Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892
| | - Jerrold M Ward
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892
| | - H Douglas Morris
- NIH Mouse Imaging Facility, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 21042
| | - Nan Yan
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390 Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Robert J Crouch
- Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892
| |
Collapse
|
20
|
Feng S, Cao Z. Is the role of human RNase H2 restricted to its enzyme activity? PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2015; 121:66-73. [PMID: 26603688 DOI: 10.1016/j.pbiomolbio.2015.11.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2015] [Revised: 11/12/2015] [Accepted: 11/17/2015] [Indexed: 11/16/2022]
Abstract
In human cells, ribonuclease (RNase) H2 complex is the predominant source of RNase H activities with possible roles in nucleic acid metabolism to preserve genome stability and to prevent immune activation. Dysfunction mutations in any of the three subunits of human RNase H2 complex can result in embryonic/perinatal lethality or cause Aicardi-Goutières syndrome (AGS). Most recently, increasing findings have shown that human RNase H2 proteins play roles beyond the RNase H2 enzymatic activities in health and disease. Firstly, the biochemical and structural properties of human RNase H2 proteins allow their interactions with various partner proteins that may support functions other than RNase H2 enzymatic activities. Secondly, the disparities of clinical presentations of AGS with different AGS-mutations and the biochemical and structural analysis of AGS-mutations, especially the results from both AGS-knockin and RNase H2-null mouse models, suggest that human RNase H2 complex has certain cellular functions beyond the RNase H2 enzymatic activities to prevent the innate-immune-mediated inflammation. Thirdly, the subunit proteins RNASEH2A and RNASEH2B respectively, not related to the RNase H2 enzymatic activities, have been shown to play a certain role in the pathophysiological processes of different cancer types. In this minireview, we aims to provide a brief overview of the most recent investigations into the biological functions of human RNase H2 proteins and the underlying mechanisms of their actions, emphasizing on the new insights into the roles of human RNase H2 proteins playing beyond the RNase H2 enzymatic activities in health and disease.
Collapse
Affiliation(s)
- Shaolong Feng
- The School of Public Health, University of South China, Hengyang 421001, China.
| | - Zhaohui Cao
- The School of Pharmacy and Life Sciences, University of South China, Hengyang 421001, China
| |
Collapse
|
21
|
Abstract
Innate immune sensing of nucleic acids provides resistance against viral infection and is important in the aetiology of autoimmune diseases. AGS (Aicardi-Goutières syndrome) is a monogenic autoinflammatory disorder mimicking in utero viral infection of the brain. Phenotypically and immunologically, it also exhibits similarities to SLE (systemic lupus erythaematosus). Three of the six genes identified to date encode components of the ribonuclease H2 complex. As all six encode enzymes involved in nucleic acid metabolism, it is thought that pathogenesis involves the accumulation of nucleic acids to stimulate an inappropriate innate immune response. Given that AGS is a monogenic disorder with a defined molecular basis, we use it as a model for common autoimmune disease to investigate cellular processes and molecular pathways responsible for nucleic-acid-mediated autoimmunity. These investigations have also provided fundamental insights into the biological roles of the RNase H2 endonuclease enzyme. In the present article, we describe how human RNase H2 and its role in AGS were first identified, and give an overview of subsequent structural, biochemical, cellular and developmental studies of this enzyme. These investigations have culminated in establishing this enzyme as a key genome-surveillance enzyme required for mammalian genome stability.
Collapse
|
22
|
Pizzi S, Sertic S, Orcesi S, Cereda C, Bianchi M, Jackson AP, Lazzaro F, Plevani P, Muzi-Falconi M. Reduction of hRNase H2 activity in Aicardi-Goutières syndrome cells leads to replication stress and genome instability. Hum Mol Genet 2014; 24:649-58. [PMID: 25274781 PMCID: PMC4291245 DOI: 10.1093/hmg/ddu485] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Aicardi-Goutières syndrome (AGS) is an inflammatory encephalopathy caused by defective nucleic acids metabolism. Over 50% of AGS mutations affect RNase H2 the only enzyme able to remove single ribonucleotide-monophosphates (rNMPs) embedded in DNA. Ribonucleotide triphosphates (rNTPs) are incorporated into genomic DNA with relatively high frequency during normal replication making DNA more susceptible to strand breakage and mutations. Here we demonstrate that human cells depleted of RNase H2 show impaired cell cycle progression associated with chronic activation of post-replication repair (PRR) and genome instability. We identify a similar phenotype in cells derived from AGS patients, which indeed accumulate rNMPs in genomic DNA and exhibit markers of constitutive PRR and checkpoint activation. Our data indicate that in human cells RNase H2 plays a crucial role in correcting rNMPs misincorporation, preventing DNA damage. Such protective function is compromised in AGS patients and may be linked to unscheduled immune responses. These findings may be relevant to shed further light on the mechanisms involved in AGS pathogenesis.
Collapse
Affiliation(s)
- Sara Pizzi
- Dipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milano, Italy
| | - Sarah Sertic
- Dipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milano, Italy
| | | | - Cristina Cereda
- Laboratory of Experimental Neurobiology, C. Mondino National Neurological Institute, Pavia, Italy and
| | - Marika Bianchi
- Laboratory of Experimental Neurobiology, C. Mondino National Neurological Institute, Pavia, Italy and
| | - Andrew P Jackson
- Medical Research Council Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Federico Lazzaro
- Dipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milano, Italy
| | - Paolo Plevani
- Dipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milano, Italy
| | - Marco Muzi-Falconi
- Dipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milano, Italy
| |
Collapse
|
23
|
Kind B, Muster B, Staroske W, Herce HD, Sachse R, Rapp A, Schmidt F, Koss S, Cardoso MC, Lee-Kirsch MA. Altered spatio-temporal dynamics of RNase H2 complex assembly at replication and repair sites in Aicardi-Goutières syndrome. Hum Mol Genet 2014; 23:5950-60. [PMID: 24986920 DOI: 10.1093/hmg/ddu319] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Ribonuclease H2 plays an essential role for genome stability as it removes ribonucleotides misincorporated into genomic DNA by replicative polymerases and resolves RNA/DNA hybrids. Biallelic mutations in the genes encoding the three RNase H2 subunits cause Aicardi-Goutières syndrome (AGS), an early-onset inflammatory encephalopathy that phenotypically overlaps with the autoimmune disorder systemic lupus erythematosus. Here we studied the intracellular dynamics of RNase H2 in living cells during DNA replication and in response to DNA damage using confocal time-lapse imaging and fluorescence cross-correlation spectroscopy. We demonstrate that the RNase H2 complex is assembled in the cytosol and imported into the nucleus in an RNase H2B-dependent manner. RNase H2 is not only recruited to DNA replication foci, but also to sites of PCNA-dependent DNA repair. By fluorescence recovery after photobleaching, we demonstrate a high mobility and fast exchange of RNase H2 at sites of DNA repair and replication. We provide evidence that recruitment of RNase H2 is not only PCNA-dependent, mediated by an interaction of the B subunit with PCNA, but also PCNA-independent mediated via the catalytic domain of the A subunit. We found that AGS-associated mutations alter complex formation, recruitment efficiency and exchange kinetics at sites of DNA replication and repair suggesting that impaired ribonucleotide removal contributes to AGS pathogenesis.
Collapse
Affiliation(s)
- Barbara Kind
- Department of Pediatrics, Medizinische Fakultät Carl Gustav Carus and
| | - Britta Muster
- Department of Biology, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Wolfgang Staroske
- Biotechnology Center, Technische Universität Dresden, 01307 Dresden, Germany
| | - Henry D Herce
- Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, New York 12180-3590, USA and
| | - René Sachse
- Institute of Earth and Environmental Science, Potsdam University, 14476 Potsdam, Germany
| | - Alexander Rapp
- Department of Biology, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Franziska Schmidt
- Department of Pediatrics, Medizinische Fakultät Carl Gustav Carus and
| | - Sarah Koss
- Department of Pediatrics, Medizinische Fakultät Carl Gustav Carus and
| | - M Cristina Cardoso
- Department of Biology, Technische Universität Darmstadt, 64287 Darmstadt, Germany,
| | - Min Ae Lee-Kirsch
- Department of Pediatrics, Medizinische Fakultät Carl Gustav Carus and
| |
Collapse
|
24
|
Henninger EE, Pursell ZF. DNA polymerase ε and its roles in genome stability. IUBMB Life 2014; 66:339-51. [PMID: 24861832 DOI: 10.1002/iub.1276] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Accepted: 05/02/2014] [Indexed: 12/14/2022]
Abstract
DNA Polymerase Epsilon (Pol ε) is one of three DNA Polymerases (along with Pol δ and Pol α) required for nuclear DNA replication in eukaryotes. Pol ε is comprised of four subunits, the largest of which is encoded by the POLE gene and contains the catalytic polymerase and exonuclease activities. The 3'-5' exonuclease proofreading activity is able to correct DNA synthesis errors and helps protect against genome instability. Recent cancer genome sequencing efforts have shown that 3% of colorectal and 7% of endometrial cancers contain mutations within the exonuclease domain of POLE and are associated with significantly elevated levels of single nucleotide substitutions (15-500 per Mb) and microsatellite stability. POLE mutations have also been found in other tumor types, though at lower frequency, suggesting roles in tumorigenesis more broadly in different tissue types. In addition to its proofreading activity, Pol ε contributes to genome stability through multiple mechanisms that are discussed in this review.
Collapse
Affiliation(s)
- Erin E Henninger
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA, USA
| | | |
Collapse
|
25
|
Rice GI, Reijns MAM, Coffin SR, Forte GMA, Anderson BH, Szynkiewicz M, Gornall H, Gent D, Leitch A, Botella MP, Fazzi E, Gener B, Lagae L, Olivieri I, Orcesi S, Swoboda KJ, Perrino FW, Jackson AP, Crow YJ. Synonymous mutations in RNASEH2A create cryptic splice sites impairing RNase H2 enzyme function in Aicardi-Goutières syndrome. Hum Mutat 2013; 34:1066-70. [PMID: 23592335 DOI: 10.1002/humu.22336] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 04/01/2013] [Indexed: 11/09/2022]
Abstract
Aicardi-Goutières syndrome is an inflammatory disorder resulting from mutations in TREX1, RNASEH2A/2B/2C, SAMHD1, or ADAR1. Here, we provide molecular, biochemical, and cellular evidence for the pathogenicity of two synonymous variants in RNASEH2A. Firstly, the c.69G>A (p.Val23Val) mutation causes the formation of a splice donor site within exon 1, resulting in an out of frame deletion at the end of exon 1, leading to reduced RNase H2 protein levels. The second mutation, c.75C>T (p.Arg25Arg), also introduces a splice donor site within exon 1, and the internal deletion of 18 amino acids. The truncated protein still forms a heterotrimeric RNase H2 complex, but lacks catalytic activity. However, as a likely result of leaky splicing, a small amount of full-length active protein is apparently produced in an individual homozygous for this mutation. Recognition of the disease causing status of these variants allows for diagnostic testing in relevant families.
Collapse
Affiliation(s)
- Gillian I Rice
- Genetic Medicine, Institute of Human Development, Faculty of Medical and Human Sciences, University of Manchester, United Kingdom
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Chon H, Sparks JL, Rychlik M, Nowotny M, Burgers PM, Crouch RJ, Cerritelli SM. RNase H2 roles in genome integrity revealed by unlinking its activities. Nucleic Acids Res 2013; 41:3130-43. [PMID: 23355612 PMCID: PMC3597693 DOI: 10.1093/nar/gkt027] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Ribonuclease H2 (RNase H2) protects genome integrity by its dual roles of resolving transcription-related R-loops and ribonucleotides incorporated in DNA during replication. To unlink these two functions, we generated a Saccharomyces cerevisiae RNase H2 mutant that can resolve R-loops but cannot cleave single ribonucleotides in DNA. This mutant definitively correlates the 2-5 bp deletions observed in rnh201Δ strains with single rNMPs in DNA. It also establishes a connection between R-loops and Sgs1-mediated replication reinitiation at stalled forks and identifies R-loops uniquely processed by RNase H2. In mouse, deletion of any of the genes coding for RNase H2 results in embryonic lethality, and in humans, RNase H2 hypomorphic mutations cause Aicardi-Goutières syndrome (AGS), a neuroinflammatory disorder. To determine the contribution of R-loops and rNMP in DNA to the defects observed in AGS, we characterized in yeast an AGS-related mutation, which is impaired in processing both substrates, but has sufficient R-loop degradation activity to complement the defects of rnh201Δ sgs1Δ strains. However, this AGS-related mutation accumulates 2-5 bp deletions at a very similar rate as the deletion strain.
Collapse
Affiliation(s)
- Hyongi Chon
- Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA, Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA and Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Trojdena Street, 02-109 Warsaw, Poland
| | - Justin L. Sparks
- Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA, Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA and Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Trojdena Street, 02-109 Warsaw, Poland
| | - Monika Rychlik
- Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA, Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA and Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Trojdena Street, 02-109 Warsaw, Poland
| | - Marcin Nowotny
- Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA, Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA and Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Trojdena Street, 02-109 Warsaw, Poland
| | - Peter M. Burgers
- Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA, Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA and Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Trojdena Street, 02-109 Warsaw, Poland
| | - Robert J. Crouch
- Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA, Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA and Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Trojdena Street, 02-109 Warsaw, Poland,*To whom correspondence should be addressed. Tel: +1 301 496 4082; Fax: +1 301 496 0243;
| | - Susana M. Cerritelli
- Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA, Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA and Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Trojdena Street, 02-109 Warsaw, Poland
| |
Collapse
|
27
|
Göksenin AY, Zahurancik W, LeCompte KG, Taggart DJ, Suo Z, Pursell ZF. Human DNA polymerase ε is able to efficiently extend from multiple consecutive ribonucleotides. J Biol Chem 2012; 287:42675-84. [PMID: 23093410 PMCID: PMC3522268 DOI: 10.1074/jbc.m112.422733] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Replicative DNA polymerases (Pols) help to maintain the high fidelity of replication in large part through their strong selectivity against mispaired deoxyribonucleotides. It has recently been demonstrated that several replicative Pols from yeast have surprisingly low selectivity for deoxyribonucleotides over their analogous ribonucleotides. In human cells, ribonucleotides are found in great abundance over deoxyribonucleotides, raising the possibility that ribonucleotides are incorporated in the human genome at significant levels during normal cellular functions. To address this possibility, the ability of human DNA polymerase ϵ to incorporate ribonucleotides was tested. At physiological concentrations of nucleotides, human Pol ϵ readily inserts and extends from incorporated ribonucleotides. Almost half of inserted ribonucleotides escape proofreading by 3′ → 5′ exonuclease-proficient Pol ϵ, indicating that ribonucleotide incorporation by Pol ϵ is likely a significant event in human cells. Human Pol ϵ is also efficient at extending from primers terminating in up to five consecutive ribonucleotides. This efficient extension appears to result from reduced exonuclease activity on primers containing consecutive 3′-terminal ribonucleotides. These biochemical properties suggest that Pol ϵ is a likely source of ribonucleotides in human genomic DNA.
Collapse
Affiliation(s)
- A Yasemin Göksenin
- Department of Biochemistry and Molecular Biology and the Tulane Cancer Center, Tulane University School of Medicine, New Orleans, Louisiana 70112, USA
| | | | | | | | | | | |
Collapse
|
28
|
Arana ME, Kerns RT, Wharey L, Gerrish KE, Bushel PR, Kunkel TA. Transcriptional responses to loss of RNase H2 in Saccharomyces cerevisiae. DNA Repair (Amst) 2012; 11:933-41. [PMID: 23079308 DOI: 10.1016/j.dnarep.2012.09.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Revised: 08/28/2012] [Accepted: 09/04/2012] [Indexed: 01/27/2023]
Abstract
We report here the transcriptional responses in Saccharomyces cerevisiae to deletion of the RNH201 gene encoding the catalytic subunit of RNase H2. Deleting RNH201 alters RNA expression of 349 genes by ≥1.5-fold (q-value <0.01), of which 123 are upregulated and 226 are downregulated. Differentially expressed genes (DEGs) include those involved in stress responses and genome maintenance, consistent with a role for RNase H2 in removing ribonucleotides incorporated into DNA during replication. Upregulated genes include several that encode subunits of RNA polymerases I and III, and genes involved in ribosomal RNA processing, ribosomal biogenesis and tRNA modification and processing, supporting a role for RNase H2 in resolving R-loops formed during transcription of rRNA and tRNA genes. A role in R-loop resolution is further suggested by a higher average GC-content proximal to the transcription start site of downregulated as compared to upregulated genes. Several DEGs are involved in telomere maintenance, supporting a role for RNase H2 in resolving RNA-DNA hybrids formed at telomeres. A large number of DEGs encode nucleases, helicases and genes involved in response to dsRNA viruses, observations that could be relevant to the nucleic acid species that elicit an innate immune response in RNase H2-defective humans.
Collapse
Affiliation(s)
- Mercedes E Arana
- Laboratory of Molecular Genetics and Laboratory of Structural Biology, National Institute of Environmental Health Sciences, NIH, DHHS, Research Triangle Park, NC 27709, USA
| | | | | | | | | | | |
Collapse
|
29
|
Powell RD, Holland PJ, Hollis T, Perrino FW. Aicardi-Goutieres syndrome gene and HIV-1 restriction factor SAMHD1 is a dGTP-regulated deoxynucleotide triphosphohydrolase. J Biol Chem 2011; 286:43596-43600. [PMID: 22069334 DOI: 10.1074/jbc.c111.317628] [Citation(s) in RCA: 284] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The SAMHD1 protein is an HIV-1 restriction factor that is targeted by the HIV-2 accessory protein Vpx in myeloid lineage cells. Mutations in the SAMHD1 gene cause Aicardi-Goutières syndrome, a genetic disease that mimics congenital viral infection. To determine the physiological function of the SAMHD1 protein, the SAMHD1 gene was cloned, recombinant protein was produced, and the catalytic activity of the purified enzyme was identified. We show that SAMHD1 contains a dGTP-regulated deoxynucleotide triphosphohydrolase. We propose that Vpx targets SAMHD1 for degradation in a viral strategy to control cellular deoxynucleotide levels for efficient replication.
Collapse
Affiliation(s)
- Rebecca D Powell
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, North Carolina 27157
| | - Paul J Holland
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, North Carolina 27157
| | - Thomas Hollis
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, North Carolina 27157
| | - Fred W Perrino
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, North Carolina 27157.
| |
Collapse
|