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Pang L, Liang N, Li C, Merriman TR, Zhang H, Yan F, Sun W, Li R, Xue X, Liu Z, Wang C, Cheng X, Chen S, Yin H, Dalbeth N, Yuan X. A stable liver-specific urate oxidase gene knockout hyperuricemia mouse model finds activated hepatic de novo purine biosynthesis and urate nephropathy. Biochim Biophys Acta Mol Basis Dis 2024; 1870:167009. [PMID: 38237409 DOI: 10.1016/j.bbadis.2023.167009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 12/25/2023] [Accepted: 12/26/2023] [Indexed: 02/20/2024]
Abstract
Urate oxidase (Uox)-deficient mice could be an optimal animal model to study hyperuricemia and associated disorders. We develop a liver-specific conditional knockout Uox-deficient (UoxCKO) mouse using the Cre/loxP gene targeting system. These UoxCKO mice spontaneously developed hyperuricemia with accumulated serum urate metabolites. Blocking urate degradation, the UoxCKO mice showed significant de novo purine biosynthesis (DNPB) in the liver along with amidophosphoribosyltransferase (Ppat). Pegloticase and allopurinol reversed the elevated serum urate (SU) levels in UoxCKO mice and suppressed the Ppat up-regulation. Although urate nephropathy occurred in 30-week-old UoxCKO mice, 90 % of Uox-deficient mice had a normal lifespan without pronounced urate transport abnormality. Thus, UoxCKO mice are a stable model of human hyperuricemia. Activated DNPB in the UoxCKO mice provides new insights into hyperuricemia, suggesting increased SU influences purine synthesis.
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Affiliation(s)
- Lei Pang
- Institute of Metabolic Diseases, Qingdao University, Qingdao, China; Shandong Provincial Key Laboratory of Metabolic Diseases, Qingdao Key Laboratory of Gout, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Ningning Liang
- CAS Key Laboratory of Nutrition, Metabolism, and Food Safety, Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences, Shanghai, China, University of Chinese Academy of Sciences, Beijing, China
| | - Changgui Li
- Institute of Metabolic Diseases, Qingdao University, Qingdao, China; Shandong Provincial Key Laboratory of Metabolic Diseases, Qingdao Key Laboratory of Gout, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Tony R Merriman
- Division of Clinical Immunology and Rheumatology, University of Alabama at Birmingham, AL, United States
| | - Hui Zhang
- Institute of Metabolic Diseases, Qingdao University, Qingdao, China
| | - Fei Yan
- Shandong Provincial Key Laboratory of Metabolic Diseases, Qingdao Key Laboratory of Gout, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Wenyan Sun
- Shandong Provincial Key Laboratory of Metabolic Diseases, Qingdao Key Laboratory of Gout, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Rui Li
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Xiaomei Xue
- Shandong Provincial Key Laboratory of Metabolic Diseases, Qingdao Key Laboratory of Gout, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Zhen Liu
- Shandong Provincial Key Laboratory of Metabolic Diseases, Qingdao Key Laboratory of Gout, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Can Wang
- Shandong Provincial Key Laboratory of Metabolic Diseases, Qingdao Key Laboratory of Gout, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Xiaoyu Cheng
- Shandong Provincial Key Laboratory of Metabolic Diseases, Qingdao Key Laboratory of Gout, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Shiting Chen
- CAS Key Laboratory of Nutrition, Metabolism, and Food Safety, Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences, Shanghai, China, University of Chinese Academy of Sciences, Beijing, China
| | - Huiyong Yin
- CAS Key Laboratory of Nutrition, Metabolism, and Food Safety, Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences, Shanghai, China, University of Chinese Academy of Sciences, Beijing, China; School of Life Science and Technology, ShanghaiTech University, Shanghai, China; Department of Biomedical Sciences, Jockey Club College of Veterinary Medicine and Medicine, State Key Laboratory of Marine Pollution (SKLMP), The Shenzhen Research Institute, City University of Hong Kong, Hong Kong, China.
| | - Nicola Dalbeth
- Department of Medicine, University of Auckland, Auckland, New Zealand.
| | - Xuan Yuan
- Institute of Metabolic Diseases, Qingdao University, Qingdao, China; Shandong Provincial Key Laboratory of Metabolic Diseases, Qingdao Key Laboratory of Gout, the Affiliated Hospital of Qingdao University, Qingdao, China.
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2
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Mahboudi S, Abbas Shojaosadati S, Maghsoudi A, Mahmoudi B. Development of a continuous fermentation process for the production of recombinant uricase enzyme by Pichia pastoris. Biotechnol Appl Biochem 2024; 71:123-131. [PMID: 37846178 DOI: 10.1002/bab.2526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Accepted: 10/07/2023] [Indexed: 10/18/2023]
Abstract
Recent studies in the biopharmaceutical industry have shown an increase in the productivity and production efficiency of recombinant proteins by continuous culture. In this research, a new upstream fermentation process was developed for the production of recombinant uricase in the methylotrophic yeast Pichia pastoris. Expression of recombinant protein in this system is under the control of the AOX1 promoter and therefore requires methanol as an inducing agent and carbon/energy source. Considering the biphasic growth characteristics of conventional fed-batch fermentation, physical separation of the growth and induction stages for better control of the continuous fermentation process resulted in higher dry-cell weight (DCW) and enhanced recombinant urate oxidase activity. The DCW and recombinant uricase activity enzyme for fed-batch fermentation were 79 g/L and 6.8 u/mL. During the continuous process, in the growth fermenter at a constant dilution rate of 0.025 h-1 , DCW increased to 88.39 g/L. In the induction fermenter, at methanol feeding rates of 30, 60, and 80 mL/h, a recombinant uricase activity was 4.13, 7.2, and 0 u/mL, respectively. The optimum methanol feeding regime in continuous fermentation resulted in a 4.5-fold improvement in productivity compared with fed-batch fermentation from 0.04 u/mL/h (0.0017 mg/mL/h) to 0.18 u/mL/h (0.0078 mg/mL/h).
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Affiliation(s)
- Sanaz Mahboudi
- Department of Biotechnology, Faculty of Chemical Engineering, Tarbiat Modares University, Tehran, Iran
| | - Seyed Abbas Shojaosadati
- Department of Biotechnology, Faculty of Chemical Engineering, Tarbiat Modares University, Tehran, Iran
| | - Amir Maghsoudi
- Department of Research and Development, PersisGen Par Company, Tehran, Iran
| | - Behrouz Mahmoudi
- Department of Medical Biotechnology, Faculty of Medicine, Alborz University of Medical Sciences, Karaj, Iran
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Mori G, Liuzzi A, Ronda L, Di Palma M, Chegkazi MS, Bui S, Garcia-Maya M, Ragazzini J, Malatesta M, Della Monica E, Rivetti C, Antin PB, Bettati S, Steiner RA, Percudani R. Cysteine Enrichment Mediates Co-Option of Uricase in Reptilian Skin and Transition to Uricotelism. Mol Biol Evol 2023; 40:msad200. [PMID: 37695804 PMCID: PMC10517255 DOI: 10.1093/molbev/msad200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 08/07/2023] [Accepted: 08/16/2023] [Indexed: 09/13/2023] Open
Abstract
Uric acid is the main means of nitrogen excretion in uricotelic vertebrates (birds and reptiles) and the end product of purine catabolism in humans and a few other mammals. While uricase is inactivated in mammals unable to degrade urate, the presence of orthologous genes without inactivating mutations in avian and reptilian genomes is unexplained. Here we show that the Gallus gallus gene we name cysteine-rich urate oxidase (CRUOX) encodes a functional protein representing a unique case of cysteine enrichment in the evolution of vertebrate orthologous genes. CRUOX retains the ability to catalyze urate oxidation to hydrogen peroxide and 5-hydroxyisourate (HIU), albeit with a 100-fold reduced efficiency. However, differently from all uricases hitherto characterized, it can also facilitate urate regeneration from HIU, a catalytic property that we propose depends on its enrichment in cysteine residues. X-ray structural analysis highlights differences in the active site compared to known orthologs and suggests a mechanism for cysteine-mediated self-aggregation under H2O2-oxidative conditions. Cysteine enrichment was concurrent with the transition to uricotelism and a shift in gene expression from the liver to the skin where CRUOX is co-expressed with β-keratins. Therefore, the loss of urate degradation in amniotes has followed opposite evolutionary trajectories: while uricase has been eliminated by pseudogenization in some mammals, it has been repurposed as a redox-sensitive enzyme in the reptilian skin.
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Affiliation(s)
- Giulia Mori
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Anastasia Liuzzi
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Luca Ronda
- Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Michele Di Palma
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Magda S Chegkazi
- Randall Centre for Cell and Molecular Biophysics, King's College London, London, UK
| | - Soi Bui
- Randall Centre for Cell and Molecular Biophysics, King's College London, London, UK
| | - Mitla Garcia-Maya
- Randall Centre for Cell and Molecular Biophysics, King's College London, London, UK
| | - Jasmine Ragazzini
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Marco Malatesta
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Emanuele Della Monica
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Claudio Rivetti
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Parker B Antin
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, USA
| | - Stefano Bettati
- Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Roberto A Steiner
- Department of Biomedical Sciences, University of Padova, Padova, Italy
- Randall Centre for Cell and Molecular Biophysics, King's College London, London, UK
| | - Riccardo Percudani
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
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Yan X, Hu W, Zhu YG, Liu QQ, Wang S, Liu HY, Zhu D, Lv ZH, Li LH, Yin YR. Cloning, Heterologous Expression, and Characterization of a Neutral Uricase from Arthrobacter sp. CSAJ-16 in Cangshan Mountain. Pol J Microbiol 2023; 72:277-283. [PMID: 37725900 PMCID: PMC10561068 DOI: 10.33073/pjm-2023-027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 06/09/2023] [Indexed: 09/21/2023] Open
Abstract
Uricase (or Urate oxidase), a key enzyme involved in purine metabolism, is commonly used in treating conditions such as gout, hyperuricemia, and tumor lysis syndrome. In this study, a uricase-producing strain (named CSAJ-16) was isolated from the soil sample of Cangshan Mountain, Yunnan Province, China. This strain was identified as Arthrobacter sp. CSAJ-16. Based on the gene sequence alignment, the uricase gene (named aruox) of Arthrobacter sp. CSAJ-16 was amplified and heterologously expressed. The recombinant uricase (ArUOX) was about 32 kDa. The optimal pH and temperature of ArUOX were pH 7 and 20°C, respectively. The ArUOX remained above 50% relative activity after incubation at 37°C for 100 min or at pH 6.0-8.6 for 24 h. Moreover, metal ions such as K+, Mg2+, Ca2+, Ba2+ and Pb2+ can significantly enhance the activity of ArUOX (> 200%). These enzymatic properties indicate that ArUOX has potential applications in pharmaceutical enzymes and uric acid detection kits.
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Affiliation(s)
- Xin Yan
- College of Agriculture and Biological Science, Dali University, Dali, People's Republic of China
| | - Wei Hu
- Department of Cardiology, The First Affiliated Hospital of Kunming Medical University, Kunming, People's Republic of China
| | - Yun-Guo Zhu
- College of Agriculture and Biological Science, Dali University, Dali, People's Republic of China
| | - Qing-Qing Liu
- College of Agriculture and Biological Science, Dali University, Dali, People's Republic of China
| | - Shuai Wang
- College of Agriculture and Biological Science, Dali University, Dali, People's Republic of China
| | - Hong-Yan Liu
- College of Agriculture and Biological Science, Dali University, Dali, People's Republic of China
| | - Dan Zhu
- College of Agriculture and Biological Science, Dali University, Dali, People's Republic of China
| | - Zhi-Hua Lv
- College of Agriculture and Biological Science, Dali University, Dali, People's Republic of China
| | - Lin-Hua Li
- Department of Cardiology, The First Affiliated Hospital of Kunming Medical University, Kunming, People's Republic of China
| | - Yi-Rui Yin
- College of Agriculture and Biological Science, Dali University, Dali, People's Republic of China
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5
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Liu Y, Jarman JB, Low YS, Augustijn HE, Huang S, Chen H, DeFeo ME, Sekiba K, Hou BH, Meng X, Weakley AM, Cabrera AV, Zhou Z, van Wezel G, Medema MH, Ganesan C, Pao AC, Gombar S, Dodd D. A widely distributed gene cluster compensates for uricase loss in hominids. Cell 2023; 186:3400-3413.e20. [PMID: 37541197 PMCID: PMC10421625 DOI: 10.1016/j.cell.2023.06.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Revised: 03/22/2023] [Accepted: 06/19/2023] [Indexed: 08/06/2023]
Abstract
Approximately 15% of US adults have circulating levels of uric acid above its solubility limit, which is causally linked to the disease gout. In most mammals, uric acid elimination is facilitated by the enzyme uricase. However, human uricase is a pseudogene, having been inactivated early in hominid evolution. Though it has long been known that uric acid is eliminated in the gut, the role of the gut microbiota in hyperuricemia has not been studied. Here, we identify a widely distributed bacterial gene cluster that encodes a pathway for uric acid degradation. Stable isotope tracing demonstrates that gut bacteria metabolize uric acid to xanthine or short chain fatty acids. Ablation of the microbiota in uricase-deficient mice causes severe hyperuricemia, and anaerobe-targeted antibiotics increase the risk of gout in humans. These data reveal a role for the gut microbiota in uric acid excretion and highlight the potential for microbiome-targeted therapeutics in hyperuricemia.
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Affiliation(s)
- Yuanyuan Liu
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - J Bryce Jarman
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | | | - Hannah E Augustijn
- Bioinformatics Group, Wageningen University, Wageningen, the Netherlands; Institute of Biology, Leiden University, Leiden, the Netherlands
| | - Steven Huang
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Haoqing Chen
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Mary E DeFeo
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Kazuma Sekiba
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Bi-Huei Hou
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Xiandong Meng
- ChEM-H Institute, Stanford University, Stanford, CA 94305, USA
| | | | | | - Zhiwei Zhou
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Gilles van Wezel
- Institute of Biology, Leiden University, Leiden, the Netherlands; Netherlands Institute of Ecology, Wageningen, the Netherlands
| | - Marnix H Medema
- Bioinformatics Group, Wageningen University, Wageningen, the Netherlands; Institute of Biology, Leiden University, Leiden, the Netherlands
| | - Calyani Ganesan
- Division of Nephrology, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Alan C Pao
- Division of Nephrology, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Urology, Stanford University School of Medicine, Stanford, CA 94305, USA; Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, USA
| | - Saurabh Gombar
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA; Atropos Health, Palo Alto, CA, USA
| | - Dylan Dodd
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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Johnson RJ, Sánchez-Lozada LG, Nakagawa T, Rodriguez-Iturbe B, Tolan D, Gaucher EA, Andrews P, Lanaspa MA. Do thrifty genes exist? Revisiting uricase. Obesity (Silver Spring) 2022; 30:1917-1926. [PMID: 36150210 PMCID: PMC9512363 DOI: 10.1002/oby.23540] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 05/26/2022] [Accepted: 06/10/2022] [Indexed: 11/07/2022]
Abstract
Sixty years ago, the geneticist James Neel proposed that the epidemics of obesity and diabetes today may have evolutionary roots. Specifically, he suggested that our ancestors may have accumulated mutations during periods of famine that provided a survival advantage at that time. However, the presence of this "thrifty genotype" in today's world, where food is plentiful, would predispose us to obesity and diabetes. The "thrifty gene" hypothesis, attractive to some, has been challenged over the years. The authors have previously postulated that the loss of the uricase gene, resulting in a rise in serum and intracellular uric acid levels, satisfies the criteria of a thrifty genotype mutation. This paper reviews and brings up-to-date the evidence supporting the hypothesis and discusses the current arguments that challenge this hypothesis. Although further studies are needed to test the hypothesis, the evidence supporting a loss of uricase as a thrifty gene is substantial and supports a role for evolutionary biology in the pathogenesis of the current obesity and diabetes epidemics.
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Affiliation(s)
- Richard J Johnson
- Division of Renal Diseases and Hypertension, University of Colorado Anschutz Medical Campus, Aurora, CO
| | | | | | - Bernardo Rodriguez-Iturbe
- Instituto Nacional de Ciencias Médicas y Nutrición “Salvador Zubirán”, Mexico City, Mexico and INC Ignacio Chavez, Mexico City, Mexico
| | - Dean Tolan
- Biology Department, Boston University, Boston MA
| | - Eric A. Gaucher
- Department of Biology, Georgia State University, Atlanta, GA
| | - Peter Andrews
- Department of Earth Sciences, Natural History Museum, London, UK
| | - Miguel A Lanaspa
- Division of Renal Diseases and Hypertension, University of Colorado Anschutz Medical Campus, Aurora, CO
- Division of Nephrology, Oregon Health Sciences University
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Gao Y, Yu Y, Qin W, Fan N, Qi Y, Chen H, Duan W. Uricase-deficient rats with similarly stable serum uric acid to human’s are sensitive model animals for studying hyperuricemia. PLoS One 2022; 17:e0264696. [PMID: 35239728 PMCID: PMC8893661 DOI: 10.1371/journal.pone.0264696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 02/15/2022] [Indexed: 11/18/2022] Open
Abstract
The aim of this study was to provide a sensitive model animal for studying hyperuricemia. Male uricase-deficient rats, named Kunming-DY rats, were raised for 130 days, or orally administered with purines and other chemicals. Serum uric acid (SUA) in the animals was assayed, and the UA level in their organs and their 24-h excretion was determined. Genes in the jejunum, ileum, kidney and liver related to UA synthesis and transportation were detected by quantitative RNA sequencing. Uricase-deficient rats have a high level of SUA and are sensitive to xanthine, adenosine, inosine, allopurinol, and alcohol. Besides, the high level of SUA in male uricase-deficient rats was stable, much higher than that in wild-type rats but similar to that in men. The distribution pattern of UA in uricase-deficient rats’ organs was different from that in wild-type rats. The kidney, liver, and small intestine were the top three organs where UA distributed, but the UA in the small intestine, colon, lung, thymus, and brain was less affected by uricase deficiency, indicating that these organs are constitutive distribution organs in UA. The 24-h UA excreted by a uricase-deficient rat was about five times higher than that excreted by a wild-type rat. However, the 24-h UA excreted through feces was not significantly changed. Both the urine volume and UA in uricase-deficient rats significantly increased, and more than 90% of UA was excreted via urine. The expression of xanthine dehydrogenase was not upregulated. Some genes of transporter associated with uric acid excretion in the kidney were significantly regulated, though not sufficient to explain the increase in SUA. In conclusion, male uricase-deficient rats’ UA metabolism is similar to that of men. The elevation of SUA in uricase-deficient rats is caused by uricase deficiency, and uricase-deficient rats are a sensitive model for studying hyperuricemia.
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Affiliation(s)
- Yinfang Gao
- The Department of Pharmacology, School of Basic Medicine, Kunming Medical University, Kunming, Yunnan Province, China
| | - Yun Yu
- The Department of Pharmacology, School of Basic Medicine, Kunming Medical University, Kunming, Yunnan Province, China
| | - Wan Qin
- The Department of Pathology, School of Basic Medicine, Yunnan University of Traditional Chinese Medicine, Kunming, Yunnan Province, China
| | - Nan Fan
- The Department of Pharmacology, School of Basic Medicine, Kunming Medical University, Kunming, Yunnan Province, China
| | - Yalin Qi
- The Department of Pharmacology, School of Basic Medicine, Kunming Medical University, Kunming, Yunnan Province, China
| | - Huan Chen
- The Department of Pharmacology, School of Basic Medicine, Kunming Medical University, Kunming, Yunnan Province, China
| | - Weigang Duan
- The Department of Pharmacology, School of Basic Medicine, Kunming Medical University, Kunming, Yunnan Province, China
- * E-mail:
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Jiang N, Xu C, Zhang L, Chen J. "Resurrected" human-source urate oxidase with high uricolytic activity and stability. Enzyme Microb Technol 2021; 149:109852. [PMID: 34311889 DOI: 10.1016/j.enzmictec.2021.109852] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 05/31/2021] [Accepted: 06/09/2021] [Indexed: 01/13/2023]
Abstract
As evidences showed that UOX(Gene ID: 391051), a single pseudogene formed after multiple mutations during human evolution, could be transcribed to mature mRNA and translated to two short peptides, we hypothesized that urate oxidase with higher homology with deduced human urate oxidase (dHU) might have lower immunogenicity. In this work, we constructed a "resurrected" human-source urate oxidase (rHU19) based on dHU. It obtained better uricolytic activity (8.29 U/mg) and catalytic efficiency (3.32 s-1 μM-1) compared with wild porcine urate oxidase (wPU) and FDA-approved porcine-baboon chimera (PBC). Maintaining high homology with dHU (93.75 %), rHU19 could be more suitable for the treatment of gout and hyperuricemia theoretically.
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Affiliation(s)
- Nan Jiang
- School of Life Science and Technology, China Pharmaceutical University, Nanjing, 210009, China
| | - Chunqin Xu
- School of Life Science and Technology, China Pharmaceutical University, Nanjing, 210009, China
| | - Linhan Zhang
- School of Life Science and Technology, China Pharmaceutical University, Nanjing, 210009, China
| | - Jianhua Chen
- School of Life Science and Technology, China Pharmaceutical University, Nanjing, 210009, China.
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Lu J, He Y, Cui L, Xing X, Liu Z, Li X, Zhang H, Li H, Sun W, Ji A, Wang Y, Yin H, Li C. Hyperuricemia Predisposes to the Onset of Diabetes via Promoting Pancreatic β-Cell Death in Uricase-Deficient Male Mice. Diabetes 2020; 69:1149-1163. [PMID: 32312870 PMCID: PMC7243290 DOI: 10.2337/db19-0704] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 03/23/2020] [Indexed: 12/16/2022]
Abstract
Clinical studies have shown a link between hyperuricemia (HU) and diabetes, while the exact effect of soluble serum urate on glucose metabolism remains elusive. This study aims to characterize the glucose metabolic phenotypes and investigate the underlying molecular mechanisms using a novel spontaneous HU mouse model in which the uricase (Uox) gene is absent. In an attempt to study the role of HU in glycometabolism, we implemented external stimulation on Uox knockout (KO) and wild-type (WT) males with a high-fat diet (HFD) and/or injections of multiple low-dose streptozotocin (MLD-STZ) to provoke the potential role of urate. Notably, while Uox-KO mice developed glucose intolerance in the basal condition, no mice spontaneously developed diabetes, even with aging. HFD-fed Uox-KO mice manifested similar insulin sensitivity compared with WT controls. HU augmented the existing glycometabolism abnormality induced by MLD-STZ and eventually led to diabetes, as evidenced by the increased random glucose. Reduced β-cell masses and increased terminal deoxynucleotidyl TUNEL-positive β-cells suggested that HU-mediated diabetes was cell death dependent. However, urate-lowering therapy (ULT) cannot ameliorate the diabetes incidence or reverse β-cell apoptosis with significance. ULT displayed a significant therapeutic effect of HU-crystal-associated kidney injury and tubulointerstitial damage in diabetes. Moreover, we present transcriptomic analysis of isolated islets, using Uox-KO versus WT mice and streptozotocin-induced diabetic WT (STZ-WT) versus diabetic Uox-KO (STZ-KO) mice. Shared differentially expressed genes of HU primacy revealed Stk17β is a possible target gene in HU-related β-cell death. Together, this study suggests that HU accelerates but does not cause diabetes by inhibiting islet β-cell survival.
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Affiliation(s)
- Jie Lu
- Shandong Provincial Key Laboratory of Metabolic Diseases, Qingdao Key Laboratory of Gout, and Department of Endocrinology and Metabolism, the Affiliated Hospital of Qingdao University, Qingdao, China
- Institute of Metabolic Diseases, Qingdao University, Qingdao, China
| | - Yuwei He
- Shandong Provincial Key Laboratory of Metabolic Diseases, Qingdao Key Laboratory of Gout, and Department of Endocrinology and Metabolism, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Lingling Cui
- Shandong Provincial Key Laboratory of Metabolic Diseases, Qingdao Key Laboratory of Gout, and Department of Endocrinology and Metabolism, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Xiaoming Xing
- Department of Pathology, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Zhen Liu
- Shandong Provincial Key Laboratory of Metabolic Diseases, Qingdao Key Laboratory of Gout, and Department of Endocrinology and Metabolism, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Xinde Li
- Shandong Provincial Key Laboratory of Metabolic Diseases, Qingdao Key Laboratory of Gout, and Department of Endocrinology and Metabolism, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Hui Zhang
- Institute of Metabolic Diseases, Qingdao University, Qingdao, China
| | - Hailong Li
- Institute of Metabolic Diseases, Qingdao University, Qingdao, China
| | - Wenyan Sun
- Institute of Metabolic Diseases, Qingdao University, Qingdao, China
| | - Aichang Ji
- Shandong Provincial Key Laboratory of Metabolic Diseases, Qingdao Key Laboratory of Gout, and Department of Endocrinology and Metabolism, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Yao Wang
- Shandong Provincial Key Laboratory of Metabolic Diseases, Qingdao Key Laboratory of Gout, and Department of Endocrinology and Metabolism, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Huiyong Yin
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences (SIBS), Chinese Academy of Sciences (CAS), Shanghai, China
| | - Changgui Li
- Shandong Provincial Key Laboratory of Metabolic Diseases, Qingdao Key Laboratory of Gout, and Department of Endocrinology and Metabolism, the Affiliated Hospital of Qingdao University, Qingdao, China
- Institute of Metabolic Diseases, Qingdao University, Qingdao, China
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10
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Yainoy S, Phuadraksa T, Wichit S, Sompoppokakul M, Songtawee N, Prachayasittikul V, Isarankura-Na-Ayudhya C. Production and Characterization of Recombinant Wild Type Uricase from Indonesian Coelacanth ( L. menadoensis) and Improvement of Its Thermostability by In Silico Rational Design and Disulphide Bridges Engineering. Int J Mol Sci 2019; 20:ijms20061269. [PMID: 30871218 PMCID: PMC6471336 DOI: 10.3390/ijms20061269] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 03/09/2019] [Accepted: 03/10/2019] [Indexed: 12/12/2022] Open
Abstract
The ideal therapeutic uricase (UOX) is expected to have the following properties; high expression level, high activity, high thermostability, high solubility and low immunogenicity. The latter property is believed to depend largely on sequence identity to the deduced human UOX (dH-UOX). Herein, we explored L. menadoensis uricase (LM-UOX) and found that it has 65% sequence identity to dH-UOX, 68% to the therapeutic chimeric porcine-baboon UOX (PBC) and 70% to the resurrected ancient mammal UOX. To study its biochemical properties, recombinant LM-UOX was produced in E. coli and purified to more than 95% homogeneity. The enzyme had specific activity up to 10.45 unit/mg, which was about 2-fold higher than that of the PBC. One-litre culture yielded purified protein up to 132 mg. Based on homology modelling, we successfully engineered I27C/N289C mutant, which was proven to contain inter-subunit disulphide bridges. The mutant had similar specific activity and production yield to that of wild type (WT) but its thermostability was dramatically improved. Up on storage at −20 °C and 4 °C, the mutant retained ~100% activity for at least 60 days. By keeping at 37 °C, the mutant retained ~100% activity for 15 days, which was 120-fold longer than that of the wild type. Thus, the I27C/N289C mutant has potential to be developed for treatment of hyperuricemia.
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Affiliation(s)
- Sakda Yainoy
- Department of Clinical Microbiology and Applied Technology, Faculty of Medical Technology, Mahidol University, Bangkok 10700, Thailand.
| | - Thanawat Phuadraksa
- Department of Clinical Microbiology and Applied Technology, Faculty of Medical Technology, Mahidol University, Bangkok 10700, Thailand.
| | - Sineewanlaya Wichit
- Department of Clinical Microbiology and Applied Technology, Faculty of Medical Technology, Mahidol University, Bangkok 10700, Thailand.
| | - Maprang Sompoppokakul
- Department of Clinical Microbiology and Applied Technology, Faculty of Medical Technology, Mahidol University, Bangkok 10700, Thailand.
| | - Napat Songtawee
- Department of Clinical Chemistry, Faculty of Medical Technology, Mahidol University, Bangkok 10700, Thailand.
| | - Virapong Prachayasittikul
- Department of Clinical Microbiology and Applied Technology, Faculty of Medical Technology, Mahidol University, Bangkok 10700, Thailand.
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11
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Lopes C, Malhão F, Guimarães C, Pinheiro I, Gonçalves JF, Castro LFC, Rocha E, Madureira TV. Testosterone-induced modulation of peroxisomal morphology and peroxisome-related gene expression in brown trout (Salmo trutta f. fario) primary hepatocytes. Aquat Toxicol 2017; 193:30-39. [PMID: 29032351 DOI: 10.1016/j.aquatox.2017.09.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Revised: 09/17/2017] [Accepted: 09/26/2017] [Indexed: 06/07/2023]
Abstract
Disruption of androgenic signaling has been linked to possible cross-modulation with other hormone-mediated pathways. Therefore, our objective was to explore effects caused by testosterone - T (1, 10 and 50μM) in peroxisomal signaling of brown trout hepatocytes. To study the underlying paths involved, several co-exposure conditions were tested, with flutamide - F (anti-androgen) and ICI 182,780 - ICI (anti-estrogen). Molecular and morphological approaches were both evaluated. Peroxisome proliferator-activated receptor alpha (PPARα), catalase and urate oxidase were the selected targets for gene expression analysis. The vitellogenin A gene was also included as a biomarker of estrogenicity. Peroxisome relative volumes were estimated by immunofluorescence, and transmission electron microscopy was used for qualitative morphological control. The single exposures of T caused a significant down-regulation of urate oxidase (10 and 50μM) and a general up-regulation of vitellogenin. A significant reduction of peroxisome relative volumes and smaller peroxisome profiles were observed at 50μM. Co-administration of T and ICI reversed the morphological modifications and vitellogenin levels. The simultaneous exposure of T and F caused a significant and concentration-dependent diminishing in vitellogenin expression. Together, the findings suggest that in the tested model, T acted via both androgen and estrogen receptors to shape the peroxisomal related targets.
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Affiliation(s)
- Célia Lopes
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), U.Porto - University of Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208, Matosinhos, Portugal; Institute of Biomedical Sciences Abel Salazar (ICBAS), U.Porto - University of Porto, Laboratory of Histology and Embryology, Department of Microscopy, Rua Jorge Viterbo Ferreira 228, P 4050-313, Porto, Portugal
| | - Fernanda Malhão
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), U.Porto - University of Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208, Matosinhos, Portugal; Institute of Biomedical Sciences Abel Salazar (ICBAS), U.Porto - University of Porto, Laboratory of Histology and Embryology, Department of Microscopy, Rua Jorge Viterbo Ferreira 228, P 4050-313, Porto, Portugal
| | - Cláudia Guimarães
- Institute of Biomedical Sciences Abel Salazar (ICBAS), U.Porto - University of Porto, Laboratory of Histology and Embryology, Department of Microscopy, Rua Jorge Viterbo Ferreira 228, P 4050-313, Porto, Portugal
| | - Ivone Pinheiro
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), U.Porto - University of Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208, Matosinhos, Portugal; Institute of Biomedical Sciences Abel Salazar (ICBAS), U.Porto - University of Porto, Laboratory of Histology and Embryology, Department of Microscopy, Rua Jorge Viterbo Ferreira 228, P 4050-313, Porto, Portugal
| | - José F Gonçalves
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), U.Porto - University of Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208, Matosinhos, Portugal; Institute of Biomedical Sciences Abel Salazar (ICBAS), U.Porto - University of Porto, Department of Aquatic Production, Rua Jorge Viterbo Ferreira 228, P 4050-313, Porto, Portugal
| | - L Filipe C Castro
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), U.Porto - University of Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208, Matosinhos, Portugal; Faculty of Sciences (FCUP), U.Porto - University of Porto, Department of Biology, Rua do Campo Alegre, P 4169-007, Porto, Portugal
| | - Eduardo Rocha
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), U.Porto - University of Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208, Matosinhos, Portugal; Institute of Biomedical Sciences Abel Salazar (ICBAS), U.Porto - University of Porto, Laboratory of Histology and Embryology, Department of Microscopy, Rua Jorge Viterbo Ferreira 228, P 4050-313, Porto, Portugal.
| | - Tânia V Madureira
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), U.Porto - University of Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208, Matosinhos, Portugal; Institute of Biomedical Sciences Abel Salazar (ICBAS), U.Porto - University of Porto, Laboratory of Histology and Embryology, Department of Microscopy, Rua Jorge Viterbo Ferreira 228, P 4050-313, Porto, Portugal
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12
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Li W, Xu S, Zhang B, Zhu Y, Hua Y, Kong X, Sun L, Hong J. Directed evolution to improve the catalytic efficiency of urate oxidase from Bacillus subtilis. PLoS One 2017; 12:e0177877. [PMID: 28531234 PMCID: PMC5439685 DOI: 10.1371/journal.pone.0177877] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 05/04/2017] [Indexed: 12/02/2022] Open
Abstract
Urate oxidase is a key enzyme in purine metabolism and catalyzes the oxidation of uric acid to allantoin. It is used to treat hyperuricemia and gout, and also in a diagnostic kit. In this study, error-prone polymerase chain reaction and staggered extension process was used to generate a mutant urate oxidase with improved enzyme activity from Bacillus subtilis. After several rounds of mutagenesis and screening, two mutants 6E9 and 8E279 were obtained which exhibited 2.99 and 3.43 times higher catalytic efficiency, respectively. They also exhibited lower optimal reaction temperature and higher thermo-stability. D44V, Q268R and K285Q were identified as the three most beneficial amino acid substitutions introduced by site-directed mutagenesis. D44V/Q268R, which was obtained through random combination of the three mutants, displayed the highest catalytic activity. The Km,kcat/Km and enzyme activity of D44V/Q268R increased by 68%, 83% and 129% respectively, compared with that of wild-type urate oxidase. Structural modeling indicated that mutations far from the active site can have significant effects on activity. For many of them, the underlying mechanisms are still difficult to explain from the static structural model. We also compared the effects of the same set of single point mutations on the wild type and on the final mutant. The results indicate strong effects of epistasis, which may imply that the mutations affect catalysis through influences on protein dynamics besides equilibrium structures.
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Affiliation(s)
- Wenjie Li
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, P. R. China
| | - Shouteng Xu
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, P. R. China
| | - Biao Zhang
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, P. R. China
| | - Yelin Zhu
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, P. R. China
| | - Yan Hua
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, P. R. China
| | - Xin Kong
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, P. R. China
| | - Lianhong Sun
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, P. R. China
| | - Jiong Hong
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, P. R. China
- * E-mail:
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13
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Lim SI, Hahn YS, Kwon I. Site-specific albumination of a therapeutic protein with multi-subunit to prolong activity in vivo. J Control Release 2015; 207:93-100. [PMID: 25862515 PMCID: PMC4430413 DOI: 10.1016/j.jconrel.2015.04.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Revised: 02/03/2015] [Accepted: 04/05/2015] [Indexed: 11/21/2022]
Abstract
Albumin fusion/conjugation (albumination) has been an effective method to prolong in vivo half-life of therapeutic proteins. However, its broader application to proteins with complex folding pathway or multi-subunit is restricted by incorrect folding, poor expression, heterogeneity, and loss of native activity of the proteins linked to albumin. We hypothesized that the site-specific conjugation of albumin to a permissive site of a target protein will expand the utilities of albumin as a therapeutic activity extender to proteins with a complex structure. We show here the genetic incorporation of a non-natural amino acid (NNAA) followed by chemoselective albumin conjugation to prolong therapeutic activity in vivo. Urate oxidase (Uox), a therapeutic enzyme for treatment of hyperuricemia, is a homotetramer with multiple surface lysines, limiting conventional approaches for albumination. Incorporation of p-azido-l-phenylalanine into two predetermined positions of Uox allowed site-specific linkage of dibenzocyclooctyne-derivatized human serum albumin (HSA) through strain-promoted azide-alkyne cycloaddition (SPAAC). The bio-orthogonality of SPAAC resulted in the production of a chemically well-defined conjugate, Uox-HSA, with a retained enzymatic activity. Uox-HSA had a half-life of 8.8 h in mice, while wild-type Uox had a half-life of 1.3 h. The AUC increased 5.5-fold (1657 vs. 303 mU/mL x h). These results clearly demonstrated that site-specific albumination led to the prolonged enzymatic activity of Uox in vivo. Site-specific albumination enabled by NNAA incorporation and orthogonal chemistry demonstrates its promise for the development of long-acting protein therapeutics with high potency and safety.
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Affiliation(s)
- Sung In Lim
- Department of Chemical Engineering, University of Virginia, VA 22904, United States
| | - Young S Hahn
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, VA 22908, United States
| | - Inchan Kwon
- Department of Chemical Engineering, University of Virginia, VA 22904, United States; School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712, Republic of Korea.
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14
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Hauck OK, Scharnberg J, Escobar NM, Wanner G, Giavalisco P, Witte CP. Uric acid accumulation in an Arabidopsis urate oxidase mutant impairs seedling establishment by blocking peroxisome maintenance. Plant Cell 2014; 26:3090-100. [PMID: 25052714 PMCID: PMC4145134 DOI: 10.1105/tpc.114.124008] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 05/30/2014] [Accepted: 07/04/2014] [Indexed: 05/21/2023]
Abstract
Purine nucleotides can be fully catabolized by plants to recycle nutrients. We have isolated a urate oxidase (uox) mutant of Arabidopsis thaliana that accumulates uric acid in all tissues, especially in the developing embryo. The mutant displays a reduced germination rate and is unable to establish autotrophic growth due to severe inhibition of cotyledon development and nutrient mobilization from the lipid reserves in the cotyledons. The uox mutant phenotype is suppressed in a xanthine dehydrogenase (xdh) uox double mutant, demonstrating that the underlying cause is not the defective purine base catabolism, or the lack of UOX per se, but the elevated uric acid concentration in the embryo. Remarkably, xanthine accumulates to similar levels in the xdh mutant without toxicity. This is paralleled in humans, where hyperuricemia is associated with many diseases whereas xanthinuria is asymptomatic. Searching for the molecular cause of uric acid toxicity, we discovered a local defect of peroxisomes (glyoxysomes) mostly confined to the cotyledons of the mature embryos, which resulted in the accumulation of free fatty acids in dry seeds. The peroxisomal defect explains the developmental phenotypes of the uox mutant, drawing a novel link between uric acid and peroxisome function, which may be relevant beyond plants.
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Affiliation(s)
- Oliver K Hauck
- Freie Universität Berlin, Dahlem Centre of Plant Sciences, Department of Plant Biochemistry, 14195 Berlin, Germany
| | - Jana Scharnberg
- Freie Universität Berlin, Dahlem Centre of Plant Sciences, Department of Plant Biochemistry, 14195 Berlin, Germany
| | - Nieves Medina Escobar
- Freie Universität Berlin, Dahlem Centre of Plant Sciences, Department of Plant Biochemistry, 14195 Berlin, Germany
| | - Gerhard Wanner
- Biozentrum der Ludwig-Maximillians-Universität München, 82152 Planegg-Martinsried, Germany
| | - Patrick Giavalisco
- Max-Planck-Institute for Molecular Plant Physiology, 14476 Potsdam, Germany
| | - Claus-Peter Witte
- Freie Universität Berlin, Dahlem Centre of Plant Sciences, Department of Plant Biochemistry, 14195 Berlin, Germany
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15
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Isoe J, Scaraffia PY. Urea synthesis and excretion in Aedes aegypti mosquitoes are regulated by a unique cross-talk mechanism. PLoS One 2013; 8:e65393. [PMID: 23755226 PMCID: PMC3673916 DOI: 10.1371/journal.pone.0065393] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2013] [Accepted: 04/29/2013] [Indexed: 12/12/2022] Open
Abstract
Aedes aegypti mosquitoes do not have a typical functional urea cycle for ammonia disposal such as the one present in most terrestrial vertebrates. However, they can synthesize urea by two different pathways, argininolysis and uricolysis. We investigated how formation of urea by these two pathways is regulated in females of A. aegypti. The expression of arginase (AR) and urate oxidase (UO), either separately or simultaneously (ARUO) was silenced by RNAi. The amounts of several nitrogen compounds were quantified in excreta using mass spectrometry. Injection of mosquitoes with either dsRNA-AR or dsRNA-UO significantly decreased the expressions of AR or UO in the fat body (FB) and Malpighian tubules (MT). Surprisingly, the expression level of AR was increased when UO was silenced and vice versa, suggesting a cross-talk regulation between pathways. In agreement with these data, the amount of urea measured 48 h after blood feeding remained unchanged in those mosquitoes injected with dsRNA-AR or dsRNA-UO. However, allantoin significantly increased in the excreta of dsRNA-AR-injected females. The knockdown of ARUO mainly led to a decrease in urea and allantoin excretion, and an increase in arginine excretion. In addition, dsRNA-AR-injected mosquitoes treated with a specific nitric oxide synthase inhibitor showed an increase of UO expression in FB and MT and a significant increase in the excretion of nitrogen compounds. Interestingly, both a temporary delay in the digestion of a blood meal and a significant reduction in the expression of several genes involved in ammonia metabolism were observed in dsRNA-AR, UO or ARUO-injected females. These results reveal that urea synthesis and excretion in A. aegypti are tightly regulated by a unique cross-talk signaling mechanism. This process allows blood-fed mosquitoes to regulate the synthesis and/or excretion of nitrogen waste products, and avoid toxic effects that could result from a lethal concentration of ammonia in their tissues.
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Affiliation(s)
- Jun Isoe
- Department of Chemistry and Biochemistry, The Center for Insect Science, The University of Arizona, Tucson, Arizona, United States of America
| | - Patricia Y. Scaraffia
- Department of Chemistry and Biochemistry, The Center for Insect Science, The University of Arizona, Tucson, Arizona, United States of America
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16
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Zhang P, Lu X, Li Q, Lin X, Liu H, Ma X. [Cloning and characterization of a thermostable urate oxidase from Microbacterium sp. strain ZZJ4-1]. Sheng Wu Gong Cheng Xue Bao 2012; 28:813-822. [PMID: 23167193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
In order to characterize a thermostable urate oxidase (Uox) from Microbacterium sp. strain ZZJ4-1, we cloned its gene (uox). The open reading frame of uox contained 894 base pairs and encoded a protein with 297 amino acids. Alignment of gene sequences indicated there was no obvious identity with the most reported uox and that 72% identity was found with uox from Arthrobacter globiformis. We inserted the gene into the plasmid pET-15b to construct an expression vector pET-15b-uox and got it induced expression in Escherichia coli BL21 (DE3). After the purification of the recombinant Uox by the HisBind column, we studied some properties of it. It was composed of subunits with a molecular mass of about 35 kDa. The optimal temperature and pH was 30 degrees C and pH 7.5. It was stable below 65 degrees C and from pH 8.5 to 11.0. The Km value was 0.22 mmol/L with the uric acid as the substrate. Ag+, Zn2+, CU2+ and SDS could totally inhibit its activity while Tween 20, Tween 80 and Triton X-100 had a slight promotion effect. The thermal stability of this enzyme was the most excellent among the reported recombinant Uox. Based on this property, it would be very useful in the application.
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Affiliation(s)
- Pengcheng Zhang
- College of Life Sciences, Zhejiang University, Hangzhou 310058, Zhejiang, China
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17
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Lee IR, Chow EWL, Morrow CA, Djordjevic JT, Fraser JA. Nitrogen metabolite repression of metabolism and virulence in the human fungal pathogen Cryptococcus neoformans. Genetics 2011; 188:309-23. [PMID: 21441208 PMCID: PMC3122321 DOI: 10.1534/genetics.111.128538] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Accepted: 03/22/2011] [Indexed: 12/28/2022] Open
Abstract
Proper regulation of metabolism is essential to maximizing fitness of organisms in their chosen environmental niche. Nitrogen metabolite repression is an example of a regulatory mechanism in fungi that enables preferential utilization of easily assimilated nitrogen sources, such as ammonium, to conserve resources. Here we provide genetic, transcriptional, and phenotypic evidence of nitrogen metabolite repression in the human pathogen Cryptococcus neoformans. In addition to loss of transcriptional activation of catabolic enzyme-encoding genes of the uric acid and proline assimilation pathways in the presence of ammonium, nitrogen metabolite repression also regulates the production of the virulence determinants capsule and melanin. Since GATA transcription factors are known to play a key role in nitrogen metabolite repression, bioinformatic analyses of the C. neoformans genome were undertaken and seven predicted GATA-type genes were identified. A screen of these deletion mutants revealed GAT1, encoding the only global transcription factor essential for utilization of a wide range of nitrogen sources, including uric acid, urea, and creatinine-three predominant nitrogen constituents found in the C. neoformans ecological niche. In addition to its evolutionarily conserved role in mediating nitrogen metabolite repression and controlling the expression of catabolic enzyme and permease-encoding genes, Gat1 also negatively regulates virulence traits, including infectious basidiospore production, melanin formation, and growth at high body temperature (39°-40°). Conversely, Gat1 positively regulates capsule production. A murine inhalation model of cryptococcosis revealed that the gat1Δ mutant is slightly more virulent than wild type, indicating that Gat1 plays a complex regulatory role during infection.
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Affiliation(s)
- I. Russel Lee
- Australian Infectious Disease Research Centre, School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD 4072 Australia and
| | - Eve W. L. Chow
- Australian Infectious Disease Research Centre, School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD 4072 Australia and
| | - Carl A. Morrow
- Australian Infectious Disease Research Centre, School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD 4072 Australia and
| | - Julianne T. Djordjevic
- Centre for Infectious Diseases and Microbiology, Westmead Millennium Institute, University of Sydney at Westmead Hospital, NSW 2145 Australia*
| | - James A. Fraser
- Australian Infectious Disease Research Centre, School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD 4072 Australia and
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Zhang J, Ren J, Li B, Liu S, Hou L, Fu L, Li J, Chen W. [Construction, expression, purification and characterization of mutant of Aspergillus flavus urate oxidase]. Sheng Wu Gong Cheng Xue Bao 2010; 26:1102-1107. [PMID: 21090115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We converted the TGC codon (307-309 bp) of Aspergillus flavus urate oxidase (UOX) gene to a GCC codon by using fusion PCR techniques to produce a C103A mutant. This gene was cloned into expression vector pET-42a (+) and then transformed into Escherichia coli BL21 (DE3). The mutant protein (UOX-Ala103) was expressed in soluble form at high levels after induction with IPTG The expressed rUOX-Ala103 accounted for about 45% of total bacterial proteins, rUOX-Ala103 of up to 98% purity was obtained after purified using hydrophobic interaction and anion exchange. Western blotting showed that the anti-UOX antibody specifically recognized rUOX-Ala103. The mutant protein showed a 60% increased in vitro biological activities compared with native protein, and performed a good activity of degrading the uric acid in vivo.
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Affiliation(s)
- Jinlong Zhang
- State Key Laboratory of Pathogens and Biosecurity, Laboratory of Applied Molecular Biology, Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing 100071, China
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Johnson RJ, Andrews P, Benner SA, Oliver W. Theodore E. Woodward award. The evolution of obesity: insights from the mid-Miocene. Trans Am Clin Climatol Assoc 2010; 121:295-308. [PMID: 20697570 PMCID: PMC2917125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
All humans are double knockouts. Humans lack the ability to synthesize vitamin C due to a mutation in L-gulono-lactone oxidase that occurred during the late Eocene, and humans have higher serum uric acid levels due to a mutation in uricase that occurred in the mid Miocene. In this paper we review the hypothesis that these mutations have in common the induction of oxidative stress that may have had prosurvival effects to enhance the effects of fructose to increase fat stores. Fructose was the primary nutrient in fruit which was the main staple of early primates, but this food likely became less available during the global cooling that occurred at the time of these mutations. However, in today's society, the intake of fructose, primarily in the form of added sugars, has skyrocketed, while the intake of natural fruits high in vitamin C has fallen. We suggest that it is the interaction of these genetic changes with diet that is responsible for the obesity epidemic today. Hence, we propose that Neel's thrifty gene hypothesis is supported by these new insights into the mechanisms regulating fructose metabolism.
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Affiliation(s)
- Richard J Johnson
- Division of Renal Diseases and Hypertension, University of Colorado, Denver, CO 80016, USA.
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Wu S, Chen B, Liu C, Ou Y, Yi J. [Expression in Escherichia coli, purification and enzymatic properties of porcine urate oxidase]. Sheng Wu Gong Cheng Xue Bao 2009; 25:1664-1670. [PMID: 20222465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The aims of this research were to construct prokaryotic expression vector containing the gene of porcine urate oxidase (pUOX), optimize the conditions of the expression of pUOX in recombinant Escherichia coli BL21(DE3), and analyze the in vitro activity and the enzymological properties of pUOX. The pUOX gene was amplified by RT-PCR from the extracted total RNA of porcine liver, and was inserted into the prokaryotic expression vector pET30a(+) to construct a recombinant expression vector pET30a(+)/pUOX. We identified the recombinant vector by endonuclease digestion and sequence analysis. The pUOX gene was amplified and cloned into the vector pET30a(+) successfully. And then the recombinant vector was transformed into E. coli BL21(DE3). The expression of pUOX with a molecular of approximately 41 kD was induced by IPTG. We also optimized the expression conditions of the recombinant protein. The recombinant protein was mostly located in the cytoplasm and it was insoluble. After the inclusion body was solved in 8 mol/L urea and refolding in 2 mol/L urea, the recombinant protein was collected and purified by Ni2+-NTA column. This recombinant protein had a specific activity of 50.61 IU/mg and showed similar properties of optimum temperature and thermal stability, base on the enzymatic assay and analysis of enzymological properties. These results would help to analyze the in vivo activity by testing animal.
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Affiliation(s)
- Shuanglin Wu
- School of Life Science and Technology, China Pharmaceutical University, Nanjing 210009, China
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Johnson RJ, Sautin YY, Oliver WJ, Roncal C, Mu W, Sanchez-Lozada LG, Rodriguez-Iturbe B, Nakagawa T, Benner SA. Lessons from comparative physiology: could uric acid represent a physiologic alarm signal gone awry in western society? J Comp Physiol B 2009; 179:67-76. [PMID: 18649082 PMCID: PMC2684327 DOI: 10.1007/s00360-008-0291-7] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2008] [Revised: 06/18/2008] [Accepted: 06/23/2008] [Indexed: 02/07/2023]
Abstract
Uric acid has historically been viewed as a purine metabolic waste product excreted by the kidney and gut that is relatively unimportant other than its penchant to crystallize in joints to cause the disease gout. In recent years, however, there has been the realization that uric acid is not biologically inert but may have a wide range of actions, including being both a pro- and anti-oxidant, a neurostimulant, and an inducer of inflammation and activator of the innate immune response. In this paper, we present the hypothesis that uric acid has a key role in the foraging response associated with starvation and fasting. We further suggest that there is a complex interplay between fructose, uric acid and vitamin C, with fructose and uric acid stimulating the foraging response and vitamin C countering this response. Finally, we suggest that the mutations in ascorbate synthesis and uricase that characterized early primate evolution were likely in response to the need to stimulate the foraging "survival" response and might have inadvertently had a role in accelerating the development of bipedal locomotion and intellectual development. Unfortunately, due to marked changes in the diet, resulting in dramatic increases in fructose- and purine-rich foods, these identical genotypic changes may be largely responsible for the epidemic of obesity, diabetes and cardiovascular disease in today's society.
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Affiliation(s)
- Richard J. Johnson
- Division of Nephrology, Hypertension and Transplantation, University of Florida, PO Box 100224, Gainesville, FL 32610, USA, e-mail:
| | - Yuri Y. Sautin
- Division of Nephrology, Hypertension and Transplantation, University of Florida, PO Box 100224, Gainesville, FL 32610, USA, e-mail:
| | | | - Carlos Roncal
- Division of Nephrology, Hypertension and Transplantation, University of Florida, PO Box 100224, Gainesville, FL 32610, USA, e-mail:
| | - Wei Mu
- Division of Nephrology, Hypertension and Transplantation, University of Florida, PO Box 100224, Gainesville, FL 32610, USA, e-mail:
| | | | | | - Takahiko Nakagawa
- Division of Nephrology, Hypertension and Transplantation, University of Florida, PO Box 100224, Gainesville, FL 32610, USA, e-mail:
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Abstract
Mapping genes in biochemical pathways allow study of the genomic organization of pathways and geneic relationships within these pathways. Additionally, molecular markers located within the boundaries of a specific gene sequence represent important marker assisted selection resources. We report map locations of two geneic markers from the purine synthesis pathway in soybean (Glycine max (L. merr.)), utilizing a 90 plant F(2) population created from the cross of "DT97-4290" x "DS97-84-1". Primers were designed based on sequences from annotated soybean complimentary DNA. A polymorphic, co-dominant, sequence-characterized amplified region marker was created for hypoxanthine phosphoribosyl transferase (EC 2.4.2.8). Linkage analysis placed this gene on linkage group (LG) O. In addition, a single-nucleotide polymorphism (SNP) marker was developed for a urate oxidase gene (EC 1.7.3.3). Linkage analysis of the SNP placed the urate oxidase gene on LG I. For both genes, amplicon sequence data confirmed the identification of the respective gene. Mapping these genes represents the first step in understanding the genomic organization of the purine biochemical pathway in soybean.
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Affiliation(s)
- J L Shultz
- Crop Genetics and Production Research Unit, USDA-ARS, Stoneville, MS 38776, USA
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Johnson RJ, Gaucher EA, Sautin YY, Henderson GN, Angerhofer AJ, Benner SA. The planetary biology of ascorbate and uric acid and their relationship with the epidemic of obesity and cardiovascular disease. Med Hypotheses 2008; 71:22-31. [PMID: 18331782 PMCID: PMC2495042 DOI: 10.1016/j.mehy.2008.01.017] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2008] [Revised: 01/07/2008] [Accepted: 01/13/2008] [Indexed: 12/13/2022]
Abstract
Humans have relatively low plasma ascorbate levels and high serum uric acid levels compared to most mammals due to the presence of genetic mutations in l-gulonolactone oxidase and uricase, respectively. We review the major hypotheses for why these mutations may have occurred. In particular, we suggest that both mutations may have provided a survival advantage to early primates by helping maintain blood pressure during periods of dietary change and environmental stress. We further propose that these mutations have the inadvertent disadvantage of increasing our risk for hypertension and cardiovascular disease in today's society characterized by Western diet and increasing physical inactivity. Finally, we suggest that a "planetary biology" approach in which genetic changes are analyzed in relation to their biological action and historical context may provide the ideal approach towards understanding the biology of the past, present and future.
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Affiliation(s)
- Richard J Johnson
- Division of Nephrology, Hypertension and Transplantation, University of Florida, and the Foundation of Applied Molecular Evolution, Gainesville, FL 32610-0224, United States.
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Terkeltaub R. Learning how and when to employ uricase as bridge therapy in refractory gout. J Rheumatol 2007; 34:1955-1958. [PMID: 17924606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
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Morozov IY, Negrete-Urtasun S, Tilburn J, Jansen CA, Caddick MX, Arst HN. Nonsense-mediated mRNA decay mutation in Aspergillus nidulans. Eukaryot Cell 2006; 5:1838-46. [PMID: 16963627 PMCID: PMC1694799 DOI: 10.1128/ec.00220-06] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
An Aspergillus nidulans mutation, designated nmdA1, has been selected as a partial suppressor of a frameshift mutation and shown to truncate the homologue of the Saccharomyces cerevisiae nonsense-mediated mRNA decay (NMD) surveillance component Nmd2p/Upf2p. nmdA1 elevates steady-state levels of premature termination codon-containing transcripts, as demonstrated using mutations in genes encoding xanthine dehydrogenase (hxA), urate oxidase (uaZ), the transcription factor mediating regulation of gene expression by ambient pH (pacC), and a protease involved in pH signal transduction (palB). nmdA1 can also stabilize pre-mRNA (unspliced) and wild-type transcripts of certain genes. Certain premature termination codon-containing transcripts which escape NMD are relatively stable, a feature more in common with certain nonsense codon-containing mammalian transcripts than with those in S. cerevisiae. As in S. cerevisiae, 5' nonsense codons are more effective at triggering NMD than 3' nonsense codons. Unlike the mammalian situation but in common with S. cerevisiae and other lower eukaryotes, A. nidulans is apparently impervious to the position of premature termination codons with respect to the 3' exon-exon junction.
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Affiliation(s)
- Igor Y Morozov
- Department of Molecular Microbiology and Infection, Flowers Building, Imperial College London, Armstrong Road, London SW7 2AZ, United Kingdom
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Andersen Ø, Aas TS, Skugor S, Takle H, van Nes S, Grisdale-Helland B, Helland SJ, Terjesen BF. Purine-induced expression of urate oxidase and enzyme activity in Atlantic salmon (Salmo salar). Cloning of urate oxidase liver cDNA from three teleost species and the African lungfish Protopterus annectens. FEBS J 2006; 273:2839-50. [PMID: 16759232 DOI: 10.1111/j.1742-4658.2006.05288.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The peroxisomal enzyme urate oxidase plays a pivotal role in the degradation of purines in both prokaryotes and eukaryotes. However, knowledge about the purine-induced expression of the encoding gene is lacking in vertebrates. These are the first published sequences of fish urate oxidase, which were predicted from PCR amplified liver cDNAs of Atlantic salmon (Salmo salar), Atlantic cod (Gadus morhua), Atlantic halibut (Hippoglossus hippoglossus) and African lungfish (Protopterus annectens). Sequence alignment of different vertebrate urate oxidases revealed amino acid substitutions of putative functional importance in the enzyme of chicken and lungfish. In the adult salmon, expression of urate oxidase mRNA predominated in liver, but was also identified in several nonhepatic organs including brain, but not in skeletal muscle and kidney. Juvenile salmon fed diets containing bacterial protein meal (BPM) rich in nucleic acids showed a significant increase in liver urate oxidase enzyme activity, and urea concentrations in plasma, muscle and liver were elevated. Whereas salmon fed the 18% BPM diet showed a nonsignificant increase in liver mRNA levels of urate oxidase compared with the 0% BPM-fed fish, no further increase in mRNA levels was found in fish receiving 36% BPM. The discrepancy between urate oxidase mRNA and enzyme activity was explained by rapid mRNA degradation or alternatively, post-translational control of the activity. Although variable plasma and liver levels of urate were detected, the substrate increased only slightly in 36% BPM-fed fish, indicating that the uricolytic pathway of Atlantic salmon is intimately regulated to handle high dietary purine levels.
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Affiliation(s)
- Øivind Andersen
- AKVAFORSK, Institute of Aquaculture Research AS, As, Norway.
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Abstract
Hyperuricemia and gout are common conditions that have long been known to have a heritable component. Obesity, diabetes, and chronic kidney failure are conditions with multifactorial inheritance that are associated with gout. In addition, social factors such as protein and alcohol intake affect serum uric acid levels. The current review discusses basic uric acid metabolism and the multigenetic inheritance of hyperuricemia. Several monogenic disorders affecting uric acid metabolism are reviewed. The genetics, pathophysiology, diagnosis, and treatment of familial juvenile hyperuricemic nephropathy/medullary cystic kidney disease, autosomal dominant disorders associated with hyperuricemia and progressive kidney failure, are described.
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Affiliation(s)
- Anthony J Bleyer
- Department of Internal Medicine, Section on Nephrology, The Wake Forest University School of Medicine, Winston-Salem, NC 27157-1053, USA.
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Kattygnarath D, Mounier N, Madelaine-Chambrin I, Gourmel B, Le Bricon T, Gisselbrecht C, Faure P, Houzé P. Quantification of urinary allantoin by capillary zone electrophoresis during recombinant urate oxydase (rasburicase) therapy. Clin Biochem 2006; 39:86-90. [PMID: 16316640 DOI: 10.1016/j.clinbiochem.2005.09.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2005] [Revised: 08/08/2005] [Accepted: 09/12/2005] [Indexed: 11/19/2022]
Abstract
OBJECTIVES Rasburicase (Fasturtec) is used to prevent or treat hyperuricemia associated with chemotherapy. We developed a capillary zone electrophoresis method to measure urinary allantoin, the degradation product of uric acid by rasburicase. DESIGN AND METHODS Electrophoresis was performed using a P/ACE 5500 system (Beckman) with a fused silica capillary tube and a UV-visible detector set at 214 nm. Urine samples from 10 patients with non-Hodgkin's lymphoma were analyzed to validate the technique. RESULTS Using a sodium tetraborate running buffer, urinary allantoin was separated from related compounds and internal standard in less than 30 min. The method was linear up to 1.25 g/L (quantification limit: 30 mg/L); precision was below 10%. The total amount of allantoin excreted in patients treated by rasburicase ranged from 1.5 g to 7.9 g/4 days. CONCLUSION This CZE assay is a simple, rapid and reproducible method to measure allantoin in urine. Different elimination profiles have been found in patients treated with rasburicase.
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Affiliation(s)
- D Kattygnarath
- Laboratoire de Biochimie A, AP-HP, 1 Avenue Claude Vellefaux, 75010 Paris, France
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Safra N, Ling GV, Schaible RH, Bannasch DL. Exclusion of Urate Oxidase as a Candidate Gene for Hyperuricosuria in the Dalmatian Dog Using an Interbreed Backcross. J Hered 2005; 96:750-4. [PMID: 15958795 DOI: 10.1093/jhered/esi078] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Hyperuricosuria, an autosomal recessive disorder, is characterized by high levels of uric acid in the urine of Dalmatian dogs. Whereas high levels of uric acid are known to be caused by the silencing of the urate oxidase (uox) gene in humans and higher primates, the molecular basis for the Dalmatian defect is unknown. Transplantation studies show that the organ responsible for the Dalmatian phenotype is the liver, which is where urate oxidase is exclusively expressed and uric acid is converted into allantoin. We cloned and sequenced the canine uox cDNA and compared the sequence between a Dalmatian and non-Dalmatian dog. No change in cDNA sequence was identified. A Dalmatian x pointer backcross family was used to track the segregation of microsatellite markers surrounding the urate oxidase locus. The uox gene was excluded for Dalmatian hyperuricosuria based on the cDNA sequence identity and negative LOD scores.
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Affiliation(s)
- N Safra
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
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Pan J, Pan X, Wang N, Ghazizadeh M, Yeldandi A. Characterization of the degradation of recombinant rat urate oxidase in tetracycline controlled gene expression cells. Microscopy (Oxf) 2005; 54:385-92. [PMID: 16131500 DOI: 10.1093/jmicro/dfi048] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2023] Open
Abstract
Our previous study has shown that uric acid is metabolized by recombinant rat urate oxidase (UOX) and generates hydrogen peroxide leading to DNA damage and cell transformation. However, in transformed cells protein levels of UOX were reduced compared with the control cell. To investigate the characterization and the mechanisms responsible for the degradation of UOX, a controllable gene expression system has been used to switch on/off controlled expression of rat UOX in vitro. Chinese hamster ovary cells were double transfected with regulatory and responsive plasmids, pCMV-tTA and pTRE-rUOX, respectively. The cells expressing rat UOX were subtly controlled by tetracycline (Tc). High levels of UOX mRNA and protein enzymatic activity were observed when the cells were cultured in the absence of Tc. The functional recombinant rat UOX was present in the form of crystalloid cores structures that localized within the peroxisomes of the cells, which was confirmed by transmission and immunoelectron microscopic studies. The addition of Tc into the medium led to the halting of rat UOX gene transcription. As a result, recombinant rat UOX mRNA was lost rapidly followed by loss of crystalloid cores structures and UOX protein degradation. Lysosomes assembled around the UOX specific structures indicating that they were involved in degradation of the protein. The observations suggest that the entire organelle rather than a single protein within the peroxisomes is degraded once the rat UOX gene expression is turned off, and the phagocytic vacuole/lysosome pathway (microautophagic process) may play an important role in degradation of the protein under the present situation.
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Affiliation(s)
- Jie Pan
- College of Life Sciences, Shandong Normal University, No. 88 East Wenhua Avenue, Jinan 250014, People's Republic of China.
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Abstract
Although most eukaryotic genomes lack operons, they contain some physical clusters of genes that are related in function despite being unrelated in sequence. How these clusters are formed during evolution is unknown. The DAL cluster is the largest metabolic gene cluster in yeast and consists of six adjacent genes encoding proteins that enable Saccharomyces cerevisiae to use allantoin as a nitrogen source. We show here that the DAL cluster was assembled, quite recently in evolutionary terms, through a set of genomic rearrangements that happened almost simultaneously. Six of the eight genes involved in allantoin degradation, which were previously scattered around the genome, became relocated to a single subtelomeric site in an ancestor of S. cerevisiae and Saccharomyces castellii. These genomic rearrangements coincided with a biochemical reorganization of the purine degradation pathway, which switched to importing allantoin instead of urate. This change eliminated urate oxidase, one of several oxygen-consuming enzymes that were lost by yeasts that can grow vigorously in anaerobic conditions. The DAL cluster is located in a domain of modified chromatin involving both H2A.Z histone exchange and Hst1-Sum1-mediated histone deacetylation, and it may be a coadapted gene complex formed by epistatic selection.
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Affiliation(s)
- Simon Wong
- Department of Genetics, Smurfit Institute, University of Dublin, Trinity College, Dublin 2, Ireland
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Abstract
Hypertension is epidemic and currently affects 25% of the world's population and is a major cause of stroke, congestive heart failure, and end-stage renal disease. Interestingly, there is evidence that the increased frequency of hypertension is a recent event in human history and correlates with dietary changes associated with Westernization. In this article, we review the evidence that links uric acid to the cause and epidemiology of hypertension. Specifically, we review the evidence that the mutation of uricase that occurred in the Miocene that resulted in a higher serum uric acid in humans compared with most other mammals may have occurred as a means to increase blood pressure in early hominoids in response to a low-sodium and low-purine diet. We then review the evidence that the epidemic of hypertension that evolved with Westernization was associated with an increase in the intake of red meat with a marked increase in serum uric acid levels. Indeed, gout and hyperuricemia should be considered a part of the obesity, type 2 diabetes, and hypertension epidemic that is occurring worldwide. Although other mechanisms certainly contribute to the pathogenesis of hypertension, the possibility that serum uric acid level may have a major role is suggested by these studies.
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Affiliation(s)
- Richard J Johnson
- Division of Nephrology, Hypertension and Transplantation, University of Florida, Gainesville, FL 32610, USA.
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Abstract
Magnetic resonance imaging (MRI) has enjoyed enormous clinical success since the first demonstration of the method more than 30 years ago. An increasing number of pharmaceutical manufacturers seeking new biomarkers for assessing drug efficacy and toxicity are turning to MRI. A specific application of MRI promises to revolutionize pathology for the basic scientist in the same way MRI has forever altered the standard of care in the clinical domain. More specifically, this application is the use of magnetic resonance microscopy (MRM) in conjunction with new staining methodologies that now make MRM routinely available to the widest range of investigators.
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Affiliation(s)
- Robert R Maronpot
- National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA.
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Abstract
The symbiotic phenotype of five Tn5-induced mutants of Rhizobium etli affected in different anabolic pathways (namely, gluconeogenesis and biosynthesis of lysine, purine, or pyrimidine) was analyzed. These mutants induced, on the root of Phaseolus vulgaris, a normal early sequence of morphogenetics events, including root hair deformation and development of nodule primordia. Later on, however, from the resulting root outgrowths, instead of nodules, one or more ectopic roots (spaced closely related and agravitropic) emerged. Therefore, this group of mutant was collectively called "root inducer" (RIND). It was observed that the RIND-induced infection threads aborted early inside the invaded root hair, and that the resulting abortive nodules lack induction of late nodulin genes. Moreover, experiments performed using a conditional mutant (a methionine-requiring invader) revealed that bacterial invasion plays a key role in the maintenance of the program of nodule development and, in particular, in the differentiation of the most specific symbiotic tissue of globose nodules, the central tissue. These data indicate that, in P. vulgaris, the nodule primordium is a root-specified pro-meristematic tissue.
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Affiliation(s)
- Simona Ferraioli
- Institute of Genetics and Biophysics A. Buzzati-Traverso, C.N.R., Via G. Marconi 10, 80125 Naples, Italy
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Robacker DC, Lauzon CR, He X. Volatiles Production and Attractiveness to the Mexican Fruit Fly of Enterobacter agglomerans Isolated from Apple Maggot and Mexican Fruit Flies. J Chem Ecol 2004; 30:1329-47. [PMID: 15503523 DOI: 10.1023/b:joec.0000037743.98703.43] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We investigated two strains of uricase (+) Enterobacter agglomerans, one isolated from the apple maggot fly (AMF) and one from the Mexican fruit fly (MFF), for 1) attractiveness to MFF, and 2) production of attractive chemicals. Regarding chemicals demonstrated attractive to the MFF, the MFF bacterial strain produced more 2,5-dimethylpyrazine, 2-phenylethanol, and indole than the AMF strain, whereas the AMF, but not the MFF strain, produced 3-hydroxybutanone. Cell types that predominated in plated subcultures varied from batch to batch resulting in variation in volatiles production, especially by the AMF strain where indole was sometimes a major component of the odor and at other times not detectable. Despite the greater production of attractive chemicals by the MFF strain, the AMF strain was consistently more attractive and the MFF strain was not different from uninoculated control plates. Statistical analyses indicated negative correlations of attractiveness with production of indole, 2,5-dimethylpyrazine, and 2-phenylethanol, and positive correlation with 3-hydroxybutanone. Results support previous findings with the Mexican fruit fly that showed combinations of attractive chemicals sometimes are not attractive.
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Affiliation(s)
- David C Robacker
- Crop Quality and Fruit Insects Research, ARS, USDA 2413 E. Highway 83, Building 200 Weslaco, Texas 78596, USA.
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37
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Abstract
In tropical legumes like Glycine, Phaseolus and Vigna sp., ammonia as direct product of symbiotic nitrogen fixation is converted to ureides (allantoin and allantoic acid) and they were translocated to the shoots as nitrogen source. In the xylem sap of soybean in reproductive phase the ureides reached to 60-75% of soluble nitrogen. In nodules infected cells (plastid and mitochondria) and uninfected cells (peroxisome) shares de novo purine biosynthesis and urate oxidation to produce ureides respectively. Current research revealed unique feathers on this symbiotic metabolism, especially on regulation of purine biosynthesis, uricase gene expression and feedback inhibition of ureides to nitrogen fixing activity.
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Affiliation(s)
- Shigeyuki Tajima
- Department of Life Science, Faculty of Agriculture, Kagawa University, Kagawa 761-0795, Japan.
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Huang SH, Wu TK. Modified colorimetric assay for uricase activity and a screen for mutant Bacillus subtilis uricase genes following StEP mutagenesis. ACTA ACUST UNITED AC 2004; 271:517-23. [PMID: 14728678 DOI: 10.1046/j.1432-1033.2003.03951.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This study describes a modified colorimetric assay for uricase activity in flexible 96-well microtiter plates using the uricase/uric acid/horseradish peroxidase/4-aminoantipyrine/3,5-dichloro-2-hydroxybenzene sulfonate colorimetric reaction. The utility of this assay was demonstrated in a screen for mutant uricase enzymes derived from the uricase gene of the thermophilic bacterium Bacillus subtilis by a modified staggered extension process (StEP) mutagenesis. An Escherichia coli library of StEP-derived uricase mutant clones was screened yielding two identical active mutant uricase genes. Two motifs conserved in eukaryotic and prokaryotic uricases are highly conserved in the mutant uricase. The mutant uricase protein was found to exhibit high uricase activity (13.1 U.mg(-1)). Finally, the modified colorimetric method is much more efficient than the conventional ones and greatly reduces assay time from 4 days to less than 20 h.
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Affiliation(s)
- Su-Hua Huang
- Department of Biological Science and Technology, National Chiao Tung University, Hsin-Chu, Taiwan, Republic of China
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39
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Affiliation(s)
- Richard J Johnson
- Division of Nephrology, Hypertension, and Transplantation, University of Florida, Gainesville, USA
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Saeed HM, Abdel-Fattah YR, Berekaa MM, Gohar YM, Elbaz MA. Identification, cloning and expression of Pseudomonas aeruginosa Ps-x putative urate oxidase gene in Escherichia coli. Pol J Microbiol 2004; 53:227-36. [PMID: 15790071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023] Open
Abstract
In a previous study we reported for the first time the isolation and characterization ofurate oxidase enzyme from Pseudomonas aeruginosa. In this work we isolated and cloned a 1.350 kilobase DNA fragment that encode a putative urate oxidase gene from the genomic library of P. aeruginosa Ps-x. The nucleotide sequence of the cloned DNA insert revealed an open reading frame that encodes a protein of a molecular weight of 54.0 kDa. The cloned DNA fragment showed an uricolytic activity when expressed in E. coli DH5alpha. Surprisingly, the nucleotide sequence of the cloned gene showed more than 99% identity to the gene encoding hypothetical protein of P. aeruginosa PAO1. Moreover, the sequence of the cloned gene was closely similar to the corresponding uricase gene of Cellulomonas flavigena (44% similarity), but showed lower similarity values to that of Bacillus sp. BT-90 (24% similarity), Candida utilis (24% similarity). Interestingly, the isolated uricase gene showed closer similarity to uricase from yeast-like symbiotic fungi Beauveria bassiana (35%), Tolypocladium inflatum (29%), Paecilomyces tenuipes (27%) and Cerataphis fransseni (24%).
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Affiliation(s)
- Hesham M Saeed
- Institute for Graduate Studies and Research, University of Alexandria, Chatby 21526, Alexandria, Egypt.
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Imhoff RD, Power NP, Borrok MJ, Tipton PA. General base catalysis in the urate oxidase reaction: evidence for a novel Thr-Lys catalytic diad. Biochemistry 2003; 42:4094-100. [PMID: 12680763 DOI: 10.1021/bi027377x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Urate oxidase catalyzes the oxidation of urate without the involvement of any cofactors. The gene encoding urate oxidase from Bacillus subtilis has been cloned and expressed, and the enzyme was purified and characterized. Formation of the urate dianion is believed to be a key step in the oxidative reaction. Rapid-mixing chemical quench studies provide evidence that the dianion is indeed an intermediate; at 15 degrees C the dianion forms within the mixing time of the rapid-quench instrument, and it disappears with a rate constant of 8 s(-)(1). Steady-state kinetic studies indicate that an ionizable group on the enzyme with a pK of 6.4 must be unprotonated for catalysis, and it is presumed that the role of this group is to abstract a proton from the substrate. Surprisingly, examination of the active site provided by the previously reported crystal structure does not reveal any obvious candidates to act as the general base. However, Thr 69 is hydrogen-bonded to the ligand at the active site, and Lys 9, which does not contact the ligand, is hydrogen-bonded to Thr 69. The T69A mutant enzyme has a V(max) that is 3% of wild type, and the K9M mutant enzyme has a V(max) that is 0.4% of wild type. The ionization at pH 6.4 that is observed with wild-type enzyme is absent in both of these mutants. It is proposed that these residues form a catalytic diad in which K9 deprotonates T69 to allow it to abstract the proton from the N9 position of the substrate to generate the dianion.
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Affiliation(s)
- Rebecca D Imhoff
- Department of Biochemistry, University of Missouri, Columbia, Missouri 65211, USA
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Huang Y, Ito R, Miura S, Yokota S, Oda T, Ito M. Altered antigenic disposition of peroxisomal urate oxidase in PEX5-defective Chinese hamster ovary cells. Biochem Biophys Res Commun 2003; 302:703-9. [PMID: 12646226 DOI: 10.1016/s0006-291x(03)00260-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Since Chinese hamster ovary (CHO) cells never express urate oxidase (UO), we tried to establish cell lines stably producing UO in order to elucidate the peroxisomal import process. The enzyme is a peroxisome targeting signal 1 (PTS1) protein harboring SKL motif at the carboxy-terminus [Biochem. Biophys. Res. Commun. 158 (1989) 991] and PEX5 protein (Pex5p) is supposed to be involved in the import process [Nat. Genet. 9 (1995) 115; J. Cell Biol. 130 (1995) 51]. We transfected a cDNA encoding rat UO into both wild type and PEX5-defective CHO cells to isolate each cell line stably producing the enzyme. While we examined the import process of UO in mutant cells, we noticed an interesting observation by using polyclonal antibody U1 or U2, which separately recognizes epitopes of UO. U1 antibody mainly interacts with epitopes in the amino-terminal region of UO. On the other hand, U2 antibody reacts with many epitopes distributed in the broad region of UO molecule. When UO produced in cultured cells was stained with U2 antibody, the enzyme was detected in peroxisomes of both wild type and PEX5-mutant cells. Whereas, U1 antibody stained the peroxisomal UO in wild type cells, but not in PEX5-mutant cells. These immunocytochemical observations suggest that the epitopes at the amino-terminal region of UO will be concealed in mutant cells. When the mutant cells were transfected with wild type PEX5 cDNA, U1 antibody came to react with UO in peroxisomes of mutant cells. The restoration indicates that the exposure of N-terminal epitopes of UO will depend upon the functional Pex5p. Immunoelectron microscopic observation showed that the peroxisomal import of UO was partially retarded in PEX5 mutant cells. The observation also supported the fact that UO was mainly localized in the peroxisomal matrix of wild type cells but in the membrane of mutant cells.
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Affiliation(s)
- Yuang Huang
- Division of Molecular Cell Biology, Saga Medical School, Nabeshima, Saga 849-8501, Japan
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Abstract
Humans have elevated serum uric acid as a result of a mutation in the urate oxidase (uricase) gene that occurred during the Miocene. We hypothesize that the mutation provided a survival advantage because of the ability of hyperuricemia to maintain blood pressure under low-salt dietary conditions, such as prevailed during that period. Mild hyperuricemia in rats acutely increases blood pressure by a renin-dependent mechanism that is most manifest under low-salt dietary conditions. Chronic hyperuricemia also causes salt sensitivity, in part by inducing preglomerular vascular disease. The vascular disease is mediated in part by uric acid-induced smooth muscle cell proliferation with activation of mitogen-activated protein kinases and stimulation of cyclooxygenase-2 and platelet-derived growth factor. Although it provided a survival advantage to early hominoids, hyperuricemia may have a major role in the current cardiovascular disease epidemic.
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Affiliation(s)
- Susumu Watanabe
- Division of Nephrology, Baylor College of Medicine, Houston, Tex 77030, USA
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Abstract
A simple purification method of the Bacillus uricase (Uao) was newly developed. The gene coding for Uao with a C-terminal 6-histidine tag (Uao-HT) was constructed and overexpressed. Using the non-specific proteases, such as proteinase K, the tag was easily removed because Uao-HT includes its C-terminal region to be specifically cleaved by them. Such treatment of Uao-HT with the proteases did not affect its enzymatic properties and enabled us to purify it from the crude extract with a single-step protocol; the cell lysate containing Uao-HT was mixed with the Ni ion-chelating magnetic beads and then the adsorbed enzyme was eluted with the proteinase K-containing buffer after untagged proteins were washed out. The isolated enzyme yielded a single band on SDS-PAGE and was fully active. This method is extremely useful for high-throughput purification of mutants because of compatibility with automation.
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Affiliation(s)
- Yoshiaki Nishiya
- Tsuruga Institute of Biotechnology, Toyobo Co., Ltd., 10-24 Toyo-cho, Tsuruga, Fukui 914-0047, Japan.
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45
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Smith PMC, Winter H, Storer PJ, Bussell JD, Schuller KA, Atkins CA. Effect of short-term N(2) deficiency on expression of the ureide pathway in cowpea root nodules. Plant Physiol 2002; 129:1216-1221. [PMID: 12114575 PMCID: PMC166515 DOI: 10.1104/pp.010714] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2001] [Revised: 02/18/2002] [Accepted: 03/18/2002] [Indexed: 05/23/2023]
Abstract
Root systems of 28-d-old cowpea (Vigna unguiculata L. Walp cv Vita 3: Bradyrhizobium sp. strain CB756) plants bearing nitrogen-fixing nodules in sand culture were exposed to an atmosphere of Ar:O(2) (80:20, v/v) for 48 h and then returned to air. Root systems of control plants were maintained in air throughout. Nodules were harvested at the same times in control and Ar:O(2)-treated root systems. Activities of two enzymes of de novo purine synthesis, glycinamide ribonucleotide transformylase (GART; EC 2.1.2.2), aminoimidazole ribonucleotide synthetase (AIRS; EC 6.3.3.1), uricase (EC 1.7.3.3), and phosphoenolpyruvate carboxylase (PEPC; EC 4.1.1.31) were measured together with the protein level of each using immune-specific polyclonal antibodies. AIRS activity and protein both declined to very low levels within 6 h in Ar:O(2) together with a decline in transcript level of pur5, the encoding gene. GART activity, protein, and transcript (pur3) levels were relatively stable. Uricase activity declined in Ar:O(2) as rapidly as AIRS activity but the protein was stable. PEPC activity showed evidence of increased sensitivity to inhibition by malate but the protein level was stable. The data indicate that the flux of fixed N from bacteroids (N(2)-fixing nodule bacteria) is in some way associated with transcriptional control over pur5 and possibly also catabolism of AIRS protein. In contrast, there is limited posttranslational control over GART and PEPC and close posttranslational control over uricase activity. The significance of these different levels of regulation is discussed in relation to the overall control of enhanced expression of plant enzymes in the cowpea symbiosis.
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Affiliation(s)
- Penelope M C Smith
- Botany Department, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
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Leal-Pinto E, Cohen BE, Lipkowitz MS, Abramson RG. Functional analysis and molecular model of the human urate transporter/channel, hUAT. Am J Physiol Renal Physiol 2002; 283:F150-63. [PMID: 12060597 DOI: 10.1152/ajprenal.00333.2001] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Recombinant protein, designated hUAT, the human homologue of the rat urate transporter/channel (UAT), functions as a highly selective urate channel in lipid bilayers. Functional analysis indicates that hUAT activity, like UAT, is selectively blocked by oxonate from its cytosolic side, whereas pyrazinoate and adenosine selectively block from the channel's extracellular face. Importantly, hUAT is a galectin, a protein with two beta-galactoside binding domains that bind lactose. Lactose significantly increased hUAT open probability but only when added to the channel's extracellular side. This effect on open probability was mimicked by glucose, but not ribose, suggesting a role for extracellular glucose in regulating hUAT channel activity. These functional observations support a four-transmembrane-domain structural model of hUAT, as previously predicted from the primary structure of UAT. hUAT and UAT, however, are not functionally identical: hUAT has a significantly lower single-channel conductance and open probability is voltage independent. These differences suggest that evolutionary changes in specific amino acids in these highly homologous proteins are functionally relevant in defining these biophysical properties.
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Affiliation(s)
- Edgar Leal-Pinto
- Division of Nephrology, Department of Medicine, Mount Sinai School of Medicine, New York, New York, 10029, USA
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Abstract
We have determined and compared the promoter, coding, and intronic sequences of the urate oxidase (Uox) gene of various primate species. Although we confirm the previous observation that the inactivation of the gene in the clade of the human and the great apes results from a single CGA to TGA nonsense mutation in exon 2, we find that the inactivation in the gibbon lineage results from an independent nonsense mutation at a different CGA codon in exon 2 or from either one-base deletion in exon 3 or one-base insertion in exon 5, contrary to the previous claim that the cause is a 13-bp deletion in exon 2. We also find that compared with other organisms, the primate functional Uox gene is exceptional in terms of usage of CGA codons which are prone to TGA nonsense mutations. Nevertheless, we demonstrate rather strong selective constraint against nonsynonymous sites of the functional Uox gene and argue that this observation is consistent with the fact that the Uox gene is unique in the genome and evolutionarily conserved not only among animals but also among eukaryotes. Another finding that there are a few substitutions in the cis-acting element or CAAT-box (or both) of primate functional Uox genes may explain the lowered transcriptional activity. We suggest that although the inactivation of the hominoid Uox gene was caused by independent nonsense or frameshift mutations, the gene has taken a two-step deterioration process, first in the promoter and second in the coding region during primate evolution. It is also argued that the high concentration of uric acid in the blood of humans and nonhuman primates has developed molecular coevolution with the xanthine oxidoreductase in purine metabolism. However, it remains to be answered whether loss of Uox activity in hominoids is related to protection from oxidative damage and the prolonged life span.
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Affiliation(s)
- Masako Oda
- Department of Biosystems Science, Graduate University for Advanced Studies (Sokendai), Hayama, Kanagawa 240-0193, Japan
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Abstract
A method for rapid morphologic phenotyping is demonstrated by using magnetic resonance microscopy. Whole fixed C57BL/6J mice were imaged at 110-microm isotropic resolution; limited volumes of the intact specimen, at 50-microm isotropic resolution; and isolated organs, at 25-microm isotropic resolution. The three-dimensional imaging technique was applied to uricase knockout mice to demonstrate the method for the evaluation of morphologic phenotype.
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Affiliation(s)
- G Allan Johnson
- Center for In Vivo Microscopy, Duke University Medical Center, Rm 141, D Bryan Neuroscience Bldg, Research Dr, Durham, NC 27710, USA.
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Shiokawa D, Tanuma SI. Isolation and characterization of the DLAD/Dlad genes, which lie head-to-head with the genes for urate oxidase. Biochem Biophys Res Commun 2001; 288:1119-28. [PMID: 11700027 DOI: 10.1006/bbrc.2001.5894] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We previously found that a novel DNA endonuclease named DLAD (DNase II-Like Acid DNase) is specifically expressed in murine liver. Here, we describe the isolation and characterization of the human DLAD and mouse Dlad genes. Both DLAD and Dlad consist of 6 exons. DLAD encodes a 361 amino acid protein sharing 34.6% amino acid identity with human DNase II. Although a recombinant protein for the putative human DLAD has a divalent cation-independent acid DNase activity, expression of the DLAD mRNA containing the entire open reading frame was not detected in any human tissues tested, except for lung, in which a short 1.1 kb transcript lacking the first two exons is expressed. Interestingly, sequence analysis of Dlad showed that the 1st exon of the urate oxidase gene, Uox, is located on the opposite strand in its 5'-flanking region. The head-to-head organization of DLAD and UOX is conserved in the human genomic sequence. Promoter analysis revealed that the intergenic region between Dlad and Uox has promoter activity for both the Dlad and Uox directions, however, the corresponding human genomic fragment has promoter activity only for DLAD. It is known that murine Uox is expressed only in the liver, whereas human UOX has been inactivated as a pseudogene. On the basis of these results, the expression of DLAD/Dlad and UOX/Uox is suggested to be coordinated by a common regulatory mechanism(s), and the balance between the two enzymes is thought to be important for maintaining the purine nucleotide pool in the liver.
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Affiliation(s)
- D Shiokawa
- Department of Biochemistry, Faculty of Pharmaceutical Sciences, Science University of Tokyo, 12 Funagawara-machi, Ichigaya, Shinjuku-ku, Tokyo 162-0826, Japan
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Cook SA, Akeson EC, Calvano C, Johnson KR, Mandell J, Hawes NL, Bronson RT, Roderick TH, Davisson MT. Mouse paracentric inversion In(3)55Rk mutates the urate oxidase gene. Cytogenet Cell Genet 2001; 93:77-82. [PMID: 11474184 DOI: 10.1159/000056953] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The paracentric inversion In(3)55Rk on mouse Chromosome 3 (Chr 3) was induced by cesium irradiation. Genetic crosses indicate the proximal breakpoint cosegregates with D3Mit324 and D3Mit92; the distal breakpoint cosegregates with D3Mit127, D3Mit160, and D3Mit200. Giemsa-banded chromosomes show the inversion spans approximately 80% of Chr 3. The proximal breakpoint occurs within band 3A2, not 3B as reported previously; the distal breakpoint occurs within band 3H3. Mice homozygous for the inversion exhibit nephropathy indicative of uricase deficiency. Southern blot analyses of urate oxidase, Uox, show two RFLPs of genomic mutant DNA: an EcoRI site between exons 4-8 and a BamHI site 3' to exon 6. Mutant cDNA fails to amplify downstream of base 844 at the 3' end of exon 7. FISH analysis of chromosomes from inversion heterozygotes, using a cosmid clone containing genomic wild-type DNA for Uox exons 2-4, shows that a 5' segment of the mutated Uox allele on the inverted chromosome has been transposed from the distal breakpoint region to the proximal breakpoint region. Clinical, histopathological, and Northern analyses indicate that our radiation-induced mutation, uox(In), is a putative null.
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Affiliation(s)
- S A Cook
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA.
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