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Han J, Liang J, Zhou W, Zhang M, Jin T. Association between NUDT17 polymorphisms and breast cancer risk. Expert Rev Mol Diagn 2024; 24:459-466. [PMID: 38756100 DOI: 10.1080/14737159.2024.2353700] [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: 10/19/2023] [Accepted: 03/18/2024] [Indexed: 05/18/2024]
Abstract
BACKGROUND Breast cancer (BC) is the leading cause of cancer death among women worldwide. The nudix hydrolase 17 (NUDT17) may play notable roles in cancer growth and metastasis. In this study, we explored the importance of NUDT17 gene polymorphism in patients with BC. METHODS In our study, 563 BC patients and 552 healthy controls participated. We used logistic regression analysis to calculate odds ratios (OR) and 95% confidence intervals (CI), and multifactor dimension reduction (MDR) analysis of SNP-SNP interactions. Finally, UALCAN and THPA databases were used for bioinformatics analysis. RESULTS The rs9286836 G allele was associated with a decreased the BC risk (p = 0.022), and the carriers of rs2004659 G allele had a 32% decreased risk of BC than individuals with allele A (p = 0.004). In the four genetic models, rs9286836 and rs2004659 reduced the risk of BC. Additionally, we found that the NUDT17 SNPs were associated with BC risk under age, tumor size, and clinical stage stratification. The MDR analysis showed that the five-locus interaction model was the best in the multi-locus model. CONCLUSION Our study found that NUDT17 single nucleotide polymorphisms are associated with BC susceptibility in Chinese Han population.
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Affiliation(s)
- Junhui Han
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, School of Life Sciences, Northwest University, Xi'an, Shaanxi, China
- College of Life Science, Northwest University, Xi'an, Shaanxi, China
- Shaanxi Provincial Key Laboratory of Biotechnology, Northwest University, Xi'an, Shaanxi, China
| | - Jing Liang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, School of Life Sciences, Northwest University, Xi'an, Shaanxi, China
- College of Life Science, Northwest University, Xi'an, Shaanxi, China
- Shaanxi Provincial Key Laboratory of Biotechnology, Northwest University, Xi'an, Shaanxi, China
| | - Wenqian Zhou
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, School of Life Sciences, Northwest University, Xi'an, Shaanxi, China
- College of Life Science, Northwest University, Xi'an, Shaanxi, China
- Shaanxi Provincial Key Laboratory of Biotechnology, Northwest University, Xi'an, Shaanxi, China
| | - Man Zhang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, School of Life Sciences, Northwest University, Xi'an, Shaanxi, China
- College of Life Science, Northwest University, Xi'an, Shaanxi, China
- Shaanxi Provincial Key Laboratory of Biotechnology, Northwest University, Xi'an, Shaanxi, China
| | - Tianbo Jin
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, School of Life Sciences, Northwest University, Xi'an, Shaanxi, China
- College of Life Science, Northwest University, Xi'an, Shaanxi, China
- Shaanxi Provincial Key Laboratory of Biotechnology, Northwest University, Xi'an, Shaanxi, China
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2
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Chen D, Zhang R, Xie A, Yuan J, Zhang J, Huang Y, Zhang H, Zhang F. Clinical correlations and prognostic value of Nudix hydroxylase 10 in patients with gastric cancer. Bioengineered 2021; 12:9779-9789. [PMID: 34696672 PMCID: PMC8809933 DOI: 10.1080/21655979.2021.1995104] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 10/12/2021] [Accepted: 10/13/2021] [Indexed: 02/05/2023] Open
Abstract
Gastric cancer (GC) is one of the most common and lethal cancers worldwide. The Nudix hydroxylase (NUDT) genes have been reported to play notable roles in tumor progression. However, the role of NUDT10 in GC has not been reported. In this study, we investigated the expression of NUDT10 in GC and its association with clinicopathological characteristics. Quantitative real-time polymerase chain reaction and analyses of The Cancer Genome Atlas and Human Protein Atlas databases were performed to determine NUDT10 mRNA and protein expression. Receiver operating characteristic curve analysis was used to assess the diagnostic value of NUDT10 in patients with GC. We used Cox regression and the Kaplan-Meier method to assess the correlations between clinicopathological factors and survival outcomes of patients with GC. Gene set enrichment analysis (GSEA) was performed to identify the underlying signaling pathways. NUDT10 mRNA and protein expression was significantly lower in GC tissues compared to normal tissues. Interestingly, higher NUDT10 expression was correlated with advanced tumor stage, deeper local invasion, and worse survival outcomes. Patients with higher NUDT10 expression had a significantly worse prognosis than those with lower NUDT10 expression. Multivariate analysis showed that high NUDT10 expression was an independent predictor of survival outcome. Several pathways, including mismatch repair, nucleotide excision repair, extracellular matrix receptor interaction, and cancer signaling, were identified as enriched pathways in GC through GSEA. To our knowledge, this study is the first to characterize NUDT10 expression in GC. Our study demonstrates that NUDT10 is a promising independent biomarker for GC prognosis.
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Affiliation(s)
- Diqun Chen
- Department of Gastrointestinal Surgery, The First Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Rouxin Zhang
- College of Science and Technology, China Three Gorges University, Yichang, China
| | - Aosi Xie
- Department of Gastrointestinal Surgery, The First Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Jinpeng Yuan
- Department of Abdominal Surgery, Cancer Hospital of Shantou University Medical College, Shantou, China
| | - Jinhai Zhang
- Department of Gastrointestinal Surgery, The First Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Yongjian Huang
- Department of Gastrointestinal Surgery, Shantou Guorui Hospital, Shantou, China
| | - Hongxia Zhang
- Health Care Center, The First Affiliated Hospital of Shantou University Medical College, Shantou, China
- CONTACT Hongxia Zhang Health Care Center, The First Affiliated Hospital of Shantou University Medical College, Shantou, China; Feiran Zhang Department of Gastrointestinal Surgery, The First Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Feiran Zhang
- Department of Gastrointestinal Surgery, The First Affiliated Hospital of Shantou University Medical College, Shantou, China
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3
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Frindert J, Kahloon MA, Zhang Y, Ahmed YL, Sinning I, Jäschke A. YvcI from Bacillus subtilis has in vitro RNA pyrophosphohydrolase activity. J Biol Chem 2019; 294:19967-19977. [PMID: 31740579 DOI: 10.1074/jbc.ra119.011485] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 11/15/2019] [Indexed: 12/23/2022] Open
Abstract
RNA degradation is one of several ways for organisms to regulate gene expression. In bacteria, the removal of two terminal phosphate moieties as orthophosphate (Bacillus subtilis) or pyrophosphate (Escherichia coli) triggers ribonucleolytic decay of primary transcripts by 5'-monophosphate-dependent ribonucleases. In the soil-dwelling firmicute species B. subtilis, the RNA pyrophosphohydrolase BsRppH, a member of the Nudix family, triggers RNA turnover by converting primary transcripts to 5'-monophospate RNA. In addition to BsRppH, a source of redundant activity in B. subtilis has been proposed. Here, using recombinant protein expression and in vitro enzyme assays, we provide evidence for several additional RNA pyrophosphohydrolases, among them MutT, NudF, YmaB, and YvcI in B. subtilis We found that in vitro, YvcI converts RNA 5'-di- and triphosphates into monophosphates in the presence of manganese at neutral to slightly acidic pH. It preferred G-initiating RNAs and required at least one unpaired nucleotide at the 5'-end of its substrates, with the 5'-terminal nucleotide determining whether primarily ortho- or pyrophosphate is released. Exchanges of catalytically important glutamate residues in the Nudix motif impaired or abolished the enzymatic activity of YvcI. In summary, the results of our extensive in vitro biochemical characterization raise the possibility that YvcI is an additional RNA pyrophosphohydrolase in B. subtilis.
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Affiliation(s)
- Jens Frindert
- Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, D-69120 Heidelberg, Germany
| | - Masroor Ahmad Kahloon
- Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, D-69120 Heidelberg, Germany
| | - Yaqing Zhang
- Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, D-69120 Heidelberg, Germany
| | - Yasar Luqman Ahmed
- Heidelberg University Biochemistry Center, Heidelberg University, D-69120 Heidelberg, Germany
| | - Irmgard Sinning
- Heidelberg University Biochemistry Center, Heidelberg University, D-69120 Heidelberg, Germany
| | - Andres Jäschke
- Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, D-69120 Heidelberg, Germany
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4
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Abstract
7,8-Dihydro-8-oxoguanine (oxoG) is the most abundant oxidative DNA lesion with dual coding properties. It forms both Watson–Crick (anti)oxoG:(anti)C and Hoogsteen (syn)oxoG:(anti)A base pairs without a significant distortion of a B-DNA helix. DNA polymerases bypass oxoG but the accuracy of nucleotide incorporation opposite the lesion varies depending on the polymerase-specific interactions with the templating oxoG and incoming nucleotides. High-fidelity replicative DNA polymerases read oxoG as a cognate base for A while treating oxoG:C as a mismatch. The mutagenic effects of oxoG in the cell are alleviated by specific systems for DNA repair and nucleotide pool sanitization, preventing mutagenesis from both direct DNA oxidation and oxodGMP incorporation. DNA translesion synthesis could provide an additional protective mechanism against oxoG mutagenesis in cells. Several human DNA polymerases of the X- and Y-families efficiently and accurately incorporate nucleotides opposite oxoG. In this review, we address the mutagenic potential of oxoG in cells and discuss the structural basis for oxoG bypass by different DNA polymerases and the mechanisms of the recognition of oxoG by DNA glycosylases and dNTP hydrolases.
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5
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Parker MJ, Maggiolo AO, Thomas WC, Kim A, Meisburger SP, Ando N, Boal AK, Stubbe J. An endogenous dAMP ligand in Bacillus subtilis class Ib RNR promotes assembly of a noncanonical dimer for regulation by dATP. Proc Natl Acad Sci U S A 2018; 115:E4594-E4603. [PMID: 29712847 PMCID: PMC5960316 DOI: 10.1073/pnas.1800356115] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The high fidelity of DNA replication and repair is attributable, in part, to the allosteric regulation of ribonucleotide reductases (RNRs) that maintains proper deoxynucleotide pool sizes and ratios in vivo. In class Ia RNRs, ATP (stimulatory) and dATP (inhibitory) regulate activity by binding to the ATP-cone domain at the N terminus of the large α subunit and altering the enzyme's quaternary structure. Class Ib RNRs, in contrast, have a partial cone domain and have generally been found to be insensitive to dATP inhibition. An exception is the Bacillus subtilis Ib RNR, which we recently reported to be inhibited by physiological concentrations of dATP. Here, we demonstrate that the α subunit of this RNR contains tightly bound deoxyadenosine 5'-monophosphate (dAMP) in its N-terminal domain and that dATP inhibition of CDP reduction is enhanced by its presence. X-ray crystallography reveals a previously unobserved (noncanonical) α2 dimer with its entire interface composed of the partial N-terminal cone domains, each binding a dAMP molecule. Using small-angle X-ray scattering (SAXS), we show that this noncanonical α2 dimer is the predominant form of the dAMP-bound α in solution and further show that addition of dATP leads to the formation of larger oligomers. Based on this information, we propose a model to describe the mechanism by which the noncanonical α2 inhibits the activity of the B. subtilis Ib RNR in a dATP- and dAMP-dependent manner.
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Affiliation(s)
- Mackenzie J Parker
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Ailiena O Maggiolo
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802
| | - William C Thomas
- Department of Chemistry, Princeton University, Princeton, NJ 08544
| | - Albert Kim
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139
| | | | - Nozomi Ando
- Department of Chemistry, Princeton University, Princeton, NJ 08544;
| | - Amie K Boal
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802;
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802
| | - JoAnne Stubbe
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139;
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
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6
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Wang Y, Wan F, Chang K, Lu X, Dai B, Ye D. NUDT expression is predictive of prognosis in patients with clear cell renal cell carcinoma. Oncol Lett 2017; 14:6121-6128. [PMID: 29113256 DOI: 10.3892/ol.2017.6997] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Accepted: 07/27/2017] [Indexed: 01/20/2023] Open
Abstract
The nudix hydroxylase (NUDT) family of genes may have notable roles in cancer growth and metastasis. The present study aimed to determine the prognostic ability of NUDT genes in clear cell renal cell carcinoma (ccRCC). Data from 509 patients with ccRCC was obtained from The Cancer Genome Atlas (TCGA) database and 192 patient samples from Fudan University Shanghai Cancer Center (FUSCC) were analyzed in the present study. The expression profile of NUDT gene family members in the TCGA cohort was obtained from the TCGA RNA sequencing database. Pathological characteristics, including age, sex, tumor size, tumor grade, stage, laterality and overall survival were collected. Cox proportional hazards regression model and Kaplan-Meier survival analysis were performed to assess the associations between pathological characteristics and expression levels of NUDT family genes. NUDT family genes that exhibited associations with overall survival (OS) were further validated in the FUSCC cohort. In the TCGA cohort, Cox proportional hazards analysis found that NUDT5 [hazards ratio (HR)=1.676; 95% confidence interval (CI), 1.097-2.559] and NUDT17 (HR=1.375; 95% CI, 1.092-1.732) were predictive of ccRCC prognosis. Further analysis revealed that low NUDT5 (P<0.0001) and NUDT17 (P<0.0001) expression were associated with poorer OS rates in the TCGA cohort. In the FUSCC cohort, low NUDT5 expression was also associated with poor OS rates (P=0.0116), and tumor grade was a factor that influenced the expression level of NUDT5 (P=0.016).
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Affiliation(s)
- Yue Wang
- Department of Urology, Fudan University Shanghai Cancer Center, Shanghai 20032, P.R. China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 20032, P.R. China
| | - Fangning Wan
- Department of Urology, Fudan University Shanghai Cancer Center, Shanghai 20032, P.R. China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 20032, P.R. China
| | - Kun Chang
- Department of Urology, Fudan University Shanghai Cancer Center, Shanghai 20032, P.R. China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 20032, P.R. China
| | - Xiaolin Lu
- Department of Urology, Fudan University Shanghai Cancer Center, Shanghai 20032, P.R. China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 20032, P.R. China
| | - Bo Dai
- Department of Urology, Fudan University Shanghai Cancer Center, Shanghai 20032, P.R. China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 20032, P.R. China
| | - Dingwei Ye
- Department of Urology, Fudan University Shanghai Cancer Center, Shanghai 20032, P.R. China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 20032, P.R. China
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7
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Srouji JR, Xu A, Park A, Kirsch JF, Brenner SE. The evolution of function within the Nudix homology clan. Proteins 2017; 85:775-811. [PMID: 27936487 PMCID: PMC5389931 DOI: 10.1002/prot.25223] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 10/15/2016] [Accepted: 11/28/2016] [Indexed: 01/01/2023]
Abstract
The Nudix homology clan encompasses over 80,000 protein domains from all three domains of life, defined by homology to each other. Proteins with a domain from this clan fall into four general functional classes: pyrophosphohydrolases, isopentenyl diphosphate isomerases (IDIs), adenine/guanine mismatch-specific adenine glycosylases (A/G-specific adenine glycosylases), and nonenzymatic activities such as protein/protein interaction and transcriptional regulation. The largest group, pyrophosphohydrolases, encompasses more than 100 distinct hydrolase specificities. To understand the evolution of this vast number of activities, we assembled and analyzed experimental and structural data for 205 Nudix proteins collected from the literature. We corrected erroneous functions or provided more appropriate descriptions for 53 annotations described in the Gene Ontology Annotation database in this family, and propose 275 new experimentally-based annotations. We manually constructed a structure-guided sequence alignment of 78 Nudix proteins. Using the structural alignment as a seed, we then made an alignment of 347 "select" Nudix homology domains, curated from structurally determined, functionally characterized, or phylogenetically important Nudix domains. Based on our review of Nudix pyrophosphohydrolase structures and specificities, we further analyzed a loop region downstream of the Nudix hydrolase motif previously shown to contact the substrate molecule and possess known functional motifs. This loop region provides a potential structural basis for the functional radiation and evolution of substrate specificity within the hydrolase family. Finally, phylogenetic analyses of the 347 select protein domains and of the complete Nudix homology clan revealed general monophyly with regard to function and a few instances of probable homoplasy. Proteins 2017; 85:775-811. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- John R. Srouji
- Plant and Microbial Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
- Molecular and Cell Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
- Present address: Molecular and Cellular Biology DepartmentHarvard UniversityCambridgeMassachusetts02138
| | - Anting Xu
- Graduate Study in Comparative Biochemistry, University of CaliforniaBerkeleyCalifornia94720
| | - Annsea Park
- Molecular and Cell Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
| | - Jack F. Kirsch
- Molecular and Cell Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
- Graduate Study in Comparative Biochemistry, University of CaliforniaBerkeleyCalifornia94720
| | - Steven E. Brenner
- Plant and Microbial Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
- Molecular and Cell Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
- Graduate Study in Comparative Biochemistry, University of CaliforniaBerkeleyCalifornia94720
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8
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Nguyen VN, Park A, Xu A, Srouji JR, Brenner SE, Kirsch JF. Substrate specificity characterization for eight putative nudix hydrolases. Evaluation of criteria for substrate identification within the Nudix family. Proteins 2016; 84:1810-1822. [PMID: 27618147 PMCID: PMC5158307 DOI: 10.1002/prot.25163] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 08/30/2016] [Accepted: 09/06/2016] [Indexed: 11/16/2022]
Abstract
The nearly 50,000 known Nudix proteins have a diverse array of functions, of which the most extensively studied is the catalyzed hydrolysis of aberrant nucleotide triphosphates. The functions of 171 Nudix proteins have been characterized to some degree, although physiological relevance of the assayed activities has not always been conclusively demonstrated. We investigated substrate specificity for eight structurally characterized Nudix proteins, whose functions were unknown. These proteins were screened for hydrolase activity against a 74-compound library of known Nudix enzyme substrates. We found substrates for four enzymes with kcat /Km values >10,000 M-1 s-1 : Q92EH0_LISIN of Listeria innocua serovar 6a against ADP-ribose, Q5LBB1_BACFN of Bacillus fragilis against 5-Me-CTP, and Q0TTC5_CLOP1 and Q0TS82_CLOP1 of Clostridium perfringens against 8-oxo-dATP and 3'-dGTP, respectively. To ascertain whether these identified substrates were physiologically relevant, we surveyed all reported Nudix hydrolytic activities against NTPs. Twenty-two Nudix enzymes are reported to have activity against canonical NTPs. With a single exception, we find that the reported kcat /Km values exhibited against these canonical substrates are well under 105 M-1 s-1 . By contrast, several Nudix enzymes show much larger kcat /Km values (in the range of 105 to >107 M-1 s-1 ) against noncanonical NTPs. We therefore conclude that hydrolytic activities exhibited by these enzymes against canonical NTPs are not likely their physiological function, but rather the result of unavoidable collateral damage occasioned by the enzymes' inability to distinguish completely between similar substrate structures. Proteins 2016; 84:1810-1822. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Vi N. Nguyen
- Molecular and Cell Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
| | - Annsea Park
- Molecular and Cell Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
| | - Anting Xu
- Graduate Program in Comparative BiochemistryUniversity of CaliforniaBerkeleyCalifornia94720
| | - John R. Srouji
- Molecular and Cell Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
- Plant and Microbial Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
- Present address: Molecular and Cellular Biology DepartmentHarvard UniversityCambridgeMA02138
| | - Steven E. Brenner
- Molecular and Cell Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
- Graduate Program in Comparative BiochemistryUniversity of CaliforniaBerkeleyCalifornia94720
- Plant and Microbial Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
| | - Jack F. Kirsch
- Molecular and Cell Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
- Graduate Program in Comparative BiochemistryUniversity of CaliforniaBerkeleyCalifornia94720
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9
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Bird JG, Zhang Y, Tian Y, Panova N, Barvík I, Greene L, Liu M, Buckley B, Krásný L, Lee JK, Kaplan CD, Ebright RH, Nickels BE. The mechanism of RNA 5′ capping with NAD+, NADH and desphospho-CoA. Nature 2016; 535:444-7. [PMID: 27383794 PMCID: PMC4961592 DOI: 10.1038/nature18622] [Citation(s) in RCA: 141] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 06/01/2016] [Indexed: 01/26/2023]
Abstract
The chemical nature of the 5′ end of RNA is a key determinant of RNA stability, processing, localization, translation efficiency1,2, and has been proposed to provide a layer of “epitranscriptomic” gene regulation3. Recently it has been shown that some bacterial RNA species carry a 5′-end structure reminiscent of the 5′ 7-methylguanylate “cap” in eukaryotic RNA. In particular, RNA species containing a 5′-end nicotinamide adenine dinucleotide (NAD+) or 3′-desphospho-coenzyme A (dpCoA) have been identified in both Gram-negative and Gram-positive bacteria3–6. It has been proposed that NAD+, reduced NAD+ (NADH), and dpCoA caps are added to RNA after transcription initiation, in a manner analogous to the addition of 7-methylguanylate caps6–8. Here, we show instead that NAD+, NADH, and dpCoA are incorporated into RNA during transcription initiation, by serving as non-canonical initiating nucleotides (NCINs) for de novo transcription initiation by cellular RNA polymerase (RNAP). We further show that both bacterial RNAP and eukaryotic RNAP II incorporate NCIN caps, that promoter DNA sequences at and upstream of the transcription start site determine the efficiency of NCIN capping, that NCIN capping occurs in vivo, and that NCIN capping has functional consequences. We report crystal structures of transcription initiation complexes containing NCIN-capped RNA products. Our results define the mechanism and structural basis of NCIN capping, and suggest that NCIN-mediated “ab initio capping” may occur in all organisms
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10
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Lian K, Leiros HKS, Moe E. MutT from the fish pathogen Aliivibrio salmonicida is a cold-active nucleotide-pool sanitization enzyme with unexpectedly high thermostability. FEBS Open Bio 2015; 5:107-16. [PMID: 25737836 PMCID: PMC4338371 DOI: 10.1016/j.fob.2015.01.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 01/13/2015] [Accepted: 01/27/2015] [Indexed: 02/08/2023] Open
Abstract
Upon infection by pathogenic bacteria, production of reactive oxygen species (ROS) is part of the host organism's first line of defence. ROS damage a number of macromolecules, and in order to withstand such a harsh environment, the bacteria need to have well-functioning ROS scavenging and repair systems. Herein, MutT is an important nucleotide-pool sanitization enzyme, which degrades 8-oxo-dGTP and thus prevents it from being incorporated into DNA. In this context, we have performed a comparative biochemical and structural analysis of MutT from the fish pathogen Aliivibrio salmonicida (AsMutT) and the human pathogen Vibrio cholerae (VcMutT), in order to analyse their function as nucleotide sanitization enzymes and also determine possible cold-adapted properties of AsMutT. The biochemical characterisation revealed that both enzymes possess activity towards the 8-oxo-dGTP substrate, and that AsMutT has a higher catalytic efficiency than VcMutT at all temperatures studied. Calculations based on the biochemical data also revealed a lower activation energy (E a) for AsMutT compared to VcMutT, and differential scanning calorimetry experiments showed that AsMutT displayed an unexpected higher melting temperature (T m) value than VcMutT. A comparative analysis of the crystal structure of VcMutT, determined to 2.42 Å resolution, and homology models of AsMutT indicate that three unique Gly residues in loops of VcMutT, and additional long range ion-pairs in AsMutT could explain the difference in temperature stability of the two enzymes. We conclude that AsMutT is a stable, cold-active enzyme with high catalytic efficiency and reduced E a, compared to the mesophilic VcMutT.
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Affiliation(s)
- Kjersti Lian
- The Norwegian Structural Biology Center (NorStruct), Department of Chemistry, The Arctic University of Norway, 9037 Tromsø, Norway
| | - Hanna-Kirsti S Leiros
- The Norwegian Structural Biology Center (NorStruct), Department of Chemistry, The Arctic University of Norway, 9037 Tromsø, Norway
| | - Elin Moe
- The Norwegian Structural Biology Center (NorStruct), Department of Chemistry, The Arctic University of Norway, 9037 Tromsø, Norway ; Macromolecular Crystallography Unit, Instituto de Tecnologia Química e Biológica (ITQB), Universidade Nova de Lisboa, Av. da República - EAN, 2780-157 Oeiras, Portugal
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11
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Initiation of mRNA decay in bacteria. Cell Mol Life Sci 2013; 71:1799-828. [PMID: 24064983 PMCID: PMC3997798 DOI: 10.1007/s00018-013-1472-4] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2013] [Revised: 09/01/2013] [Accepted: 09/03/2013] [Indexed: 12/24/2022]
Abstract
The instability of messenger RNA is fundamental to the control of gene expression. In bacteria, mRNA degradation generally follows an "all-or-none" pattern. This implies that if control is to be efficient, it must occur at the initiating (and presumably rate-limiting) step of the degradation process. Studies of E. coli and B. subtilis, species separated by 3 billion years of evolution, have revealed the principal and very disparate enzymes involved in this process in the two organisms. The early view that mRNA decay in these two model organisms is radically different has given way to new models that can be resumed by "different enzymes-similar strategies". The recent characterization of key ribonucleases sheds light on an impressive case of convergent evolution that illustrates that the surprisingly similar functions of these totally unrelated enzymes are of general importance to RNA metabolism in bacteria. We now know that the major mRNA decay pathways initiate with an endonucleolytic cleavage in E. coli and B. subtilis and probably in many of the currently known bacteria for which these organisms are considered representative. We will discuss here the different pathways of eubacterial mRNA decay, describe the major players and summarize the events that can precede and/or favor nucleolytic inactivation of a mRNA, notably the role of the 5' end and translation initiation. Finally, we will discuss the role of subcellular compartmentalization of transcription, translation, and the RNA degradation machinery.
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12
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McLennan AG. Substrate ambiguity among the nudix hydrolases: biologically significant, evolutionary remnant, or both? Cell Mol Life Sci 2013; 70:373-85. [PMID: 23184251 PMCID: PMC11113851 DOI: 10.1007/s00018-012-1210-3] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 11/01/2012] [Accepted: 11/05/2012] [Indexed: 12/20/2022]
Abstract
Many members of the nudix hydrolase family exhibit considerable substrate multispecificity and ambiguity, which raises significant issues when assessing their functions in vivo and gives rise to errors in database annotation. Several display low antimutator activity when expressed in bacterial tester strains as well as some degree of activity in vitro towards mutagenic, oxidized nucleotides such as 8-oxo-dGTP. However, many of these show greater activity towards other nucleotides such as ADP-ribose or diadenosine tetraphosphate (Ap(4)A). The antimutator activities have tended to gain prominence in the literature, whereas they may in fact represent the residual activity of an ancestral antimutator enzyme that has become secondary to the more recently evolved major activity after gene duplication. Whether any meaningful antimutagenic function has also been retained in vivo requires very careful assessment. Then again, other examples of substrate ambiguity may indicate as yet unexplored regulatory systems. For example, bacterial Ap(4)A hydrolases also efficiently remove pyrophosphate from the 5' termini of mRNAs, suggesting a potential role for Ap(4)A in the control of bacterial mRNA turnover, while the ability of some eukaryotic mRNA decapping enzymes to degrade IDP and dIDP or diphosphoinositol polyphosphates (DIPs) may also be indicative of new regulatory networks in RNA metabolism. DIP phosphohydrolases also degrade diadenosine polyphosphates and inorganic polyphosphates, suggesting further avenues for investigation. This article uses these and other examples to highlight the need for a greater awareness of the possible significance of substrate ambiguity among the nudix hydrolases as well as the need to exert caution when interpreting incomplete analyses.
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Affiliation(s)
- Alexander G McLennan
- Institute of Integrative Biology, University of Liverpool, Biosciences Building, Crown St., Liverpool, L69 7ZB, UK.
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Abstract
From microbes to multicellular eukaryotic organisms, all cells contain pathways responsible for genome maintenance. DNA replication allows for the faithful duplication of the genome, whereas DNA repair pathways preserve DNA integrity in response to damage originating from endogenous and exogenous sources. The basic pathways important for DNA replication and repair are often conserved throughout biology. In bacteria, high-fidelity repair is balanced with low-fidelity repair and mutagenesis. Such a balance is important for maintaining viability while providing an opportunity for the advantageous selection of mutations when faced with a changing environment. Over the last decade, studies of DNA repair pathways in bacteria have demonstrated considerable differences between Gram-positive and Gram-negative organisms. Here we review and discuss the DNA repair, genome maintenance, and DNA damage checkpoint pathways of the Gram-positive bacterium Bacillus subtilis. We present their molecular mechanisms and compare the functions and regulation of several pathways with known information on other organisms. We also discuss DNA repair during different growth phases and the developmental program of sporulation. In summary, we present a review of the function, regulation, and molecular mechanisms of DNA repair and mutagenesis in Gram-positive bacteria, with a strong emphasis on B. subtilis.
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Richards J, Liu Q, Pellegrini O, Celesnik H, Yao S, Bechhofer DH, Condon C, Belasco JG. An RNA pyrophosphohydrolase triggers 5'-exonucleolytic degradation of mRNA in Bacillus subtilis. Mol Cell 2011; 43:940-9. [PMID: 21925382 PMCID: PMC3176438 DOI: 10.1016/j.molcel.2011.07.023] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Revised: 05/31/2011] [Accepted: 07/14/2011] [Indexed: 11/29/2022]
Abstract
In Escherichia coli, RNA degradation often begins with conversion of the 5'-terminal triphosphate to a monophosphate, creating a better substrate for internal cleavage by RNase E. Remarkably, no homolog of this key endonuclease is present in many bacterial species, such as Bacillus subtilis and various pathogens. Here, we report that the degradation of primary transcripts in B. subtilis can nevertheless be triggered by an analogous process to generate a short-lived, monophosphorylated intermediate. Like its E. coli counterpart, the B. subtilis RNA pyrophosphohydrolase that catalyzes this event is a Nudix protein that prefers unpaired 5' ends. However, in B. subtilis, this modification exposes transcripts to rapid 5' exonucleolytic degradation by RNase J, which is absent in E. coli but present in most bacteria lacking RNase E. This pathway, which closely resembles the mechanism by which deadenylated mRNA is degraded in eukaryotic cells, explains the stabilizing influence of 5'-terminal stem-loops in such bacteria.
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Affiliation(s)
- Jamie Richards
- Kimmel Center for Biology and Medicine at the Skirball Institute and Department of Microbiology, New York University School of Medicine, 540 First Avenue, New York, NY 10016, USA
| | - Quansheng Liu
- Kimmel Center for Biology and Medicine at the Skirball Institute and Department of Microbiology, New York University School of Medicine, 540 First Avenue, New York, NY 10016, USA
| | - Olivier Pellegrini
- CNRS UPR 9073 (affiliated with Université de Paris Diderot, Sorbonne Paris Cité) and Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Helena Celesnik
- Kimmel Center for Biology and Medicine at the Skirball Institute and Department of Microbiology, New York University School of Medicine, 540 First Avenue, New York, NY 10016, USA
| | - Shiyi Yao
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine of New York University, Box 1603, 1 Gustave L. Levy Place, New York, NY 10029, USA
| | - David H. Bechhofer
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine of New York University, Box 1603, 1 Gustave L. Levy Place, New York, NY 10029, USA
| | - Ciarán Condon
- CNRS UPR 9073 (affiliated with Université de Paris Diderot, Sorbonne Paris Cité) and Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Joel G. Belasco
- Kimmel Center for Biology and Medicine at the Skirball Institute and Department of Microbiology, New York University School of Medicine, 540 First Avenue, New York, NY 10016, USA
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Joye IJ, Beliën T, Delcour JA. The first characterised wheat (Triticum aestivum L.) member of the nudix hydrolase family shows specificity for NAD(P)(H) and FAD. J Cereal Sci 2010. [DOI: 10.1016/j.jcs.2010.01.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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16
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Nakamura T, Meshitsuka S, Kitagawa S, Abe N, Yamada J, Ishino T, Nakano H, Tsuzuki T, Doi T, Kobayashi Y, Fujii S, Sekiguchi M, Yamagata Y. Structural and dynamic features of the MutT protein in the recognition of nucleotides with the mutagenic 8-oxoguanine base. J Biol Chem 2010; 285:444-52. [PMID: 19864691 PMCID: PMC2804192 DOI: 10.1074/jbc.m109.066373] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Revised: 10/14/2009] [Indexed: 11/06/2022] Open
Abstract
Escherichia coli MutT hydrolyzes 8-oxo-dGTP to 8-oxo-dGMP, an event that can prevent the misincorporation of 8-oxoguanine opposite adenine in DNA. Of the several enzymes that recognize 8-oxoguanine, MutT exhibits high substrate specificity for 8-oxoguanine nucleotides; however, the structural basis for this specificity is unknown. The crystal structures of MutT in the apo and holo forms and in the binary and ternary forms complexed with the product 8-oxo-dGMP and 8-oxo-dGMP plus Mn(2+), respectively, were determined. MutT strictly recognizes the overall conformation of 8-oxo-dGMP through a number of hydrogen bonds. This recognition mode revealed that 8-oxoguanine nucleotides are discriminated from guanine nucleotides by not only the hydrogen bond between the N7-H and Odelta (N119) atoms but also by the syn glycosidic conformation that 8-oxoguanine nucleotides prefer. Nevertheless, these discrimination factors cannot by themselves explain the roughly 34,000-fold difference between the affinity of MutT for 8-oxo-dGMP and dGMP. When the binary complex of MutT with 8-oxo-dGMP is compared with the ligand-free form, ordering and considerable movement of the flexible loops surrounding 8-oxo-dGMP in the binary complex are observed. These results indicate that MutT specifically recognizes 8-oxoguanine nucleotides by the ligand-induced conformational change.
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Affiliation(s)
- Teruya Nakamura
- From the Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973
| | - Sachiko Meshitsuka
- the Graduate School of Pharmaceutical Sciences, Osaka University, Suita 565-0871
| | - Seiju Kitagawa
- the Graduate School of Pharmaceutical Sciences, Osaka University, Suita 565-0871
| | - Nanase Abe
- the Graduate School of Pharmaceutical Sciences, Osaka University, Suita 565-0871
| | - Junichi Yamada
- the Graduate School of Pharmaceutical Sciences, Osaka University, Suita 565-0871
| | - Tetsuya Ishino
- the Graduate School of Pharmaceutical Sciences, Osaka University, Suita 565-0871
| | - Hiroaki Nakano
- the Graduate School of Pharmaceutical Sciences, Osaka University, Suita 565-0871
| | - Teruhisa Tsuzuki
- the Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582
| | - Takefumi Doi
- the Graduate School of Pharmaceutical Sciences, Osaka University, Suita 565-0871
| | - Yuji Kobayashi
- the Graduate School of Pharmaceutical Sciences, Osaka University, Suita 565-0871
| | - Satoshi Fujii
- the School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8526, and
| | | | - Yuriko Yamagata
- From the Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973
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Buchko GW, Litvinova O, Robinson H, Yakunin AF, Kennedy MA. Functional and structural characterization of DR_0079 from Deinococcus radiodurans, a novel Nudix hydrolase with a preference for cytosine (deoxy)ribonucleoside 5'-Di- and triphosphates. Biochemistry 2008; 47:6571-82. [PMID: 18512963 PMCID: PMC2867059 DOI: 10.1021/bi800099d] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The genome of the extremely radiation resistant bacterium Deinococcus radiodurans encodes 21 Nudix hydrolases, of which only two have been characterized in detail. Here we report the activity and crystal structure for DR_0079, the first Nudix hydrolase observed to have a marked preference for cytosine ribonucleoside 5'-diphosphate (CDP) and cytosine ribonucleoside 5'-triphosphate (CTP). After CDP and CTP, the next most preferred substrates for DR_0079, with a relative activity of <50%, were the corresponding deoxyribose nucleotides, dCDP and dCTP. Hydrolase activity at the site of the phosphodiester bond was corroborated using (31)P NMR spectroscopy to follow the phosphorus resonances for three substrates, CDP, IDP, and CTP, and their hydrolysis products, CMP + P(i), IMP + P(i), and CMP + PP(i), respectively. Nucleophilic substitution at the beta-phosphorus of CDP and CTP was established, using (31)P NMR spectroscopy, by the appearance of an upfield-shifted P(i) resonance and line-broadened PP(i) resonance, respectively, when the hydrolysis was performed in 40% H(2)(18)O-enriched water. The optimal activity for CDP was at pH 9.0-9.5 with the reaction requiring divalent metal cation (Mg(2+) > Mn(2+) > Co(2+)). The biochemical data are discussed with reference to the crystal structure for DR_0079 that was determined in the metal-free form at 1.9 A resolution. The protein contains nine beta-strands, three alpha-helices, and two 3(10)-helices organized into three subdomains: an N-terminal beta-sheet, a central Nudix core, and a C-terminal helix-turn-helix motif. As observed for all known structures of Nudix hydrolases, the alpha-helix of the "Nudix box" is one of two helices that sandwich a "four-strand" mixed beta-sheet. To identify residues potentially involved in metal and substrate binding, NMR chemical shift mapping experiments were performed on (15)N-labeled DR_0079 with the paramagnetic divalent cation Co(2+) and the nonhydrolyzable substrate thymidine 5'-O-(alpha,beta-methylenediphosphate) and the results mapped onto the crystal structure.
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Affiliation(s)
- Garry W Buchko
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
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Robleto EA, Yasbin R, Ross C, Pedraza-Reyes M. Stationary phase mutagenesis in B. subtilis: a paradigm to study genetic diversity programs in cells under stress. Crit Rev Biochem Mol Biol 2008; 42:327-39. [PMID: 17917870 DOI: 10.1080/10409230701597717] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
One of the experimental platforms to study programs increasing genetic diversity in cells under stressful or nondividing conditions is adaptive mutagenesis, also called stationary phase mutagenesis or stress-induced mutagenesis. In some model systems, there is evidence that mutagenesis occurs in genes that are actively transcribed. Some of those genes may be actively transcribed as a result of environmental stress giving the appearance of directed mutation. That is, cells under conditions of starvation or other stresses accumulate mutations in transcribed genes, including those transcribed because of the selective pressure. An important question concerns how, within the context of stochastic processes, a cell biases mutation to genes under selection pressure? Because the mechanisms underlying DNA transactions in prokaryotic cells are well conserved among the three domains of life, these studies are likely to apply to the examination of genetic programs in eukaryotes. In eukaryotes, increasing genetic diversity in differentiated cells has been implicated in neoplasia and cell aging. Historically, Escherichia coli has been the paradigm used to discern the cellular processes driving the generation of adaptive mutations; however, examining adaptive mutation in Bacillus subtilis has contributed new insights. One noteworthy contribution is that the B. subtilis' ability to accumulate chromosomal mutations under conditions of starvation is influenced by cell differentiation and transcriptional derepression, as well as by proteins homologous to transcription and repair factors. Here we revise and discuss concepts pertaining to genetic programs that increase diversity in B. subtilis cells under nutritional stress.
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Fisher DI, Cartwright JL, McLennan AG. Characterization of the Mn2+-stimulated (di)adenosine polyphosphate hydrolase encoded by the Deinococcus radiodurans DR2356 nudix gene. Arch Microbiol 2006; 186:415-24. [PMID: 16900379 DOI: 10.1007/s00203-006-0155-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2006] [Revised: 06/26/2006] [Accepted: 07/17/2006] [Indexed: 10/24/2022]
Abstract
The DR2356 nudix hydrolase gene from Deinococcus radiodurans has been cloned and the product expressed as an 18 kDa histidine-tagged protein. The enzyme hydrolysed adenosine and diadenosine polyphosphates, always generating ATP as one of the initial products. ATP and other (deoxy)nucleoside triphosphates were also substrates, yielding (d)NDP and Pi as products. The DR2356 protein was most active at pH 8.6-9.0 and showed a strong preference for Mn(2+) as activating cation. Mg(2+) ions at 15 mM supported only 5% of the activity achieved with 2 mM Mn(2+). K (m) and k (cat) values for diadenosine tetra-, penta- and hexaphosphates were 2.0, 2.4 and 1.1 microM and 11.4, 28.6 and 12.0 s(-1), respectively, while for GTP they were 20.3 microM and 1.8 s(-1), respectively. The K (m )for adenosine 5'-pentaphosphate was <1 microM. Expression analysis showed the DR2356 gene to be induced eight- to ninefold in stationary phase and in cells subjected to slow dehydration plus rehydration. Superoxide (but not peroxide) treatment and rapid dehydration caused a two-to threefold induction. The Mn-requirement and induction in stationary phase suggest that DR2356 may have a specific role in maintenance mode metabolism in stationary phase as Mn(2+) accumulates.
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Affiliation(s)
- David I Fisher
- School of Biological Sciences, Biosciences Building, University of Liverpool, P.O. Box 147, Liverpool, UK
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20
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Jambunathan N, Mahalingam R. Analysis of Arabidopsis growth factor gene 1 (GFG1) encoding a nudix hydrolase during oxidative signaling. PLANTA 2006; 224:1-11. [PMID: 16328543 DOI: 10.1007/s00425-005-0183-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2005] [Accepted: 11/08/2005] [Indexed: 05/05/2023]
Abstract
Maintenance of pyridine nucleotide homeostasis is vital for normal growth and development of plants and animals. We demonstrate that Arabidopsis Growth Factor Gene 1 (GFG1; At4g12720) encoding a nudix hydrolase, is an NADH pyrophosphatase and ADP-ribose pyrophosphatase. The affinity for NADH and ADP-ribose indicates that this enzyme could serve as a connection between sensing cellular redox changes and downstream signaling. GFG1 transcript levels were rapidly and transiently induced during both biotic stresses imposed by avirulent pathogens and abiotic stresses like ozone and osmoticum. T-DNA knock out plants of GFG1 gene, gfg1-1, exhibit pleiotropic phenotypes such as reduced size, increased levels of reactive oxygen species and NADH, microscopic cell death, constitutive expression of pathogenesis-related genes and enhanced resistance to bacterial pathogens. The recombinant protein failed to complement the mutator deficiency in SBMutT- strain of Escherichia coli, suggesting this protein may not play a role in sanitizing the nucleotide pool. Based on rapid transcriptional changes in response to various stresses, substrate specificity of the enzyme, and analysis of the knock out mutant, we propose that GFG1 is a key gene linking cellular metabolism and oxidative signaling.
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Affiliation(s)
- Niranjani Jambunathan
- Department of Biochemistry and Molecular Biology, 246 Noble Research center, Oklahoma State University, Stillwater, OK 74078, USA
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