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Li M, Tian X, Li X, Huang M, Huang S, Wu Y, Jiang M, Shi Y, Shi L, Wang Z. Diverse energy metabolism patterns in females in Neodon fuscus, Lasiopodomys brandtii, and Mus musculus revealed by comparative transcriptomics under hypoxic conditions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 783:147130. [PMID: 34088150 DOI: 10.1016/j.scitotenv.2021.147130] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 03/28/2021] [Accepted: 04/09/2021] [Indexed: 06/12/2023]
Abstract
The effects of global warming and anthropogenic disturbance force animals to migrate from lower to higher elevations to find suitable new habitats. As such migrations increase hypoxic stress on the animals, it is important to understand how plateau- and plain-dwelling animals respond to low-oxygen environments. We used comparative transcriptomics to explore the response of Neodon fuscus, Lasiopodomys brandtii, and Mus musculus skeletal muscle tissues to hypoxic conditions. Results indicate that these species have adopted different oxygen transport and energy metabolism strategies for dealing with a hypoxic environment. N. fuscus promotes oxygen transport by increasing hemoglobin synthesis and reduces the risk of thrombosis through cooperative regulation of genes, including Fga, Fgb, Alb, and Ttr; genes such as Acs16, Gpat4, and Ndufb7 are involved in regulating lipid synthesis, fatty acid β-oxidation, hemoglobin synthesis, and electron-linked transmission, thereby maintaining a normal energy supply in hypoxic conditions. In contrast, the oxygen-carrying capacity and angiogenesis of red blood cells in L. brandtii are promoted by genes in the CYP and COL families; this species maintains its bodily energy supply by enhancing the pentose phosphate pathway and mitochondrial fatty acid synthesis pathway. However, under hypoxia, M. musculus cannot effectively transport additional oxygen; thus, its cell cycle, proliferation, and migration are somewhat affected. Given its lack of hypoxic tolerance experience, M. musculus also shows significantly reduced oxidative phosphorylation levels under hypoxic conditions. Our results suggest that the glucose capacity of M. musculus skeletal muscle does not provide sufficient energy during hypoxia; thus, we hypothesize that it supplements its bodily energy by synthesizing ketone bodies. For the first time, we describe the energy metabolism pathways of N. fuscus and L. brandtii skeletal muscle tissues under hypoxic conditions. Our findings, therefore, improve our understanding of how vertebrates thrive in high altitude and plain habitats when faced with hypoxic conditions.
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Affiliation(s)
- Mengyang Li
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, Henan, China
| | - Xiangyu Tian
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, Henan, China
| | - Xiujuan Li
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, Henan, China
| | - Maolin Huang
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, Henan, China
| | - Shuang Huang
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, Henan, China
| | - Yue Wu
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, Henan, China
| | - Mengwan Jiang
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, Henan, China
| | - Yuhua Shi
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, Henan, China
| | - Luye Shi
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, Henan, China.
| | - Zhenlong Wang
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, Henan, China; School of Physical Education (Main campus), Zhengzhou University, Zhengzhou 450001, Henan, China.
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Vadlakonda L, Indracanti M, Kalangi SK, Gayatri BM, Naidu NG, Reddy ABM. The Role of Pi, Glutamine and the Essential Amino Acids in Modulating the Metabolism in Diabetes and Cancer. J Diabetes Metab Disord 2020; 19:1731-1775. [PMID: 33520860 DOI: 10.1007/s40200-020-00566-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 06/04/2020] [Indexed: 02/07/2023]
Abstract
Purpose Re-examine the current metabolic models. Methods Review of literature and gene networks. Results Insulin activates Pi uptake, glutamine metabolism to stabilise lipid membranes. Tissue turnover maintains the metabolic health. Current model of intermediary metabolism (IM) suggests glucose is the source of energy, and anaplerotic entry of fatty acids and amino acids into mitochondria increases the oxidative capacity of the TCA cycle to produce the energy (ATP). The reduced cofactors, NADH and FADH2, have different roles in regulating the oxidation of nutrients, membrane potentials and biosynthesis. Trans-hydrogenation of NADH to NADPH activates the biosynthesis. FADH2 sustains the membrane potential during the cell transformations. Glycolytic enzymes assume the non-canonical moonlighting functions, enter the nucleus to remodel the genetic programmes to affect the tissue turnover for efficient use of nutrients. Glycosylation of the CD98 (4F2HC) stabilises the nutrient transporters and regulates the entry of cysteine, glutamine and BCAA into the cells. A reciprocal relationship between the leucine and glutamine entry into cells regulates the cholesterol and fatty acid synthesis and homeostasis in cells. Insulin promotes the Pi transport from the blood to tissues, activates the mitochondrial respiratory activity, and glutamine metabolism, which activates the synthesis of cholesterol and the de novo fatty acids for reorganising and stabilising the lipid membranes for nutrient transport and signal transduction in response to fluctuations in the microenvironmental cues. Fatty acids provide the lipid metabolites, activate the second messengers and protein kinases. Insulin resistance suppresses the lipid raft formation and the mitotic slippage activates the fibrosis and slow death pathways.
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Affiliation(s)
| | - Meera Indracanti
- Institute of Biotechnology, University of Gondar, Gondar, Ethiopia
| | - Suresh K Kalangi
- Amity Stem Cell Institute, Amity University Haryana, Amity Education Valley Pachgaon, Manesar, Gurugram, HR 122413 India
| | - B Meher Gayatri
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad, 500046 India
| | - Navya G Naidu
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad, 500046 India
| | - Aramati B M Reddy
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad, 500046 India
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More Than One HMG-CoA Lyase: The Classical Mitochondrial Enzyme Plus the Peroxisomal and the Cytosolic Ones. Int J Mol Sci 2019; 20:ijms20246124. [PMID: 31817290 PMCID: PMC6941031 DOI: 10.3390/ijms20246124] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 11/27/2019] [Accepted: 11/29/2019] [Indexed: 12/27/2022] Open
Abstract
There are three human enzymes with HMG-CoA lyase activity that are able to synthesize ketone bodies in different subcellular compartments. The mitochondrial HMG-CoA lyase was the first to be described, and catalyzes the cleavage of 3-hydroxy-3-methylglutaryl CoA to acetoacetate and acetyl-CoA, the common final step in ketogenesis and leucine catabolism. This protein is mainly expressed in the liver and its function is metabolic, since it produces ketone bodies as energetic fuels when glucose levels are low. Another isoform is encoded by the same gene for the mitochondrial HMG-CoA lyase (HMGCL), but it is located in peroxisomes. The last HMG-CoA lyase to be described is encoded by a different gene, HMGCLL1, and is located in the cytosolic side of the endoplasmic reticulum membrane. Some activity assays and tissue distribution of this enzyme have shown the brain and lung as key tissues for studying its function. Although the roles of the peroxisomal and cytosolic HMG-CoA lyases remain unknown, recent studies highlight the role of ketone bodies in metabolic remodeling, homeostasis, and signaling, providing new insights into the molecular and cellular function of these enzymes.
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Hemmerlin A, Huchelmann A, Tritsch D, Schaller H, Bach TJ. The specific molecular architecture of plant 3-hydroxy-3-methylglutaryl-CoA lyase. J Biol Chem 2019; 294:16186-16197. [PMID: 31515272 DOI: 10.1074/jbc.ra119.008839] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 08/20/2019] [Indexed: 11/06/2022] Open
Abstract
3-Hydroxy-3-methylglutaryl-CoA (HMG-CoA) lyase (HMGL) is involved in branched-chain amino acid catabolism leading to acetyl-CoA production. Here, using bioinformatics analyses and protein sequence alignments, we found that in Arabidopsis thaliana a single gene encodes two HMGL isoforms differing in size (51 kDa, HMGL51 and 46 kDa, HMGL46). Similar to animal HMGLs, both isoforms comprised a C-terminal type 1 peroxisomal retention motif, and HMGL51 contained a mitochondrial leader peptide. We observed that only a shortened HMGL (35 kDa, HMGL35) is conserved across all kingdoms of life. Most notably, all plant HMGLs also contained a specific N-terminal extension (P100) that is located between the N-terminal mitochondrial targeting sequence TP35 and HMGL35 and is absent in bacteria and other eukaryotes. Interestingly, using HMGL enzyme assays, we found that rather than HMGL46, homodimeric recombinant HMGL35 is the active enzyme catalyzing acetyl-CoA and acetoacetate synthesis when incubated with (S)-HMG-CoA. This suggested that the plant-specific P100 peptide may inactivate HMGL according to specific physiological requirements. Therefore, we investigated whether the P100 peptide in HMGL46 alters its activity, possibly by modifying the HMGL46 structure. We found that induced expression of a cytosolic HMGL35 version in A. thaliana delays germination and leads to rapid wilting and chlorosis in mature plants. Our results suggest that in plants, P100-mediated HMGL inactivation outside of peroxisomes or mitochondria is crucial, protecting against potentially cytotoxic effects of HMGL activity while it transits to these organelles.
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Affiliation(s)
- Andréa Hemmerlin
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, 12 rue du Général Zimmer, F-67084 Strasbourg, France
| | - Alexandre Huchelmann
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, 12 rue du Général Zimmer, F-67084 Strasbourg, France
| | - Denis Tritsch
- Institut de Chimie de Strasbourg, 4 rue Blaise Pascal, F-67081 Strasbourg, France
| | - Hubert Schaller
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, 12 rue du Général Zimmer, F-67084 Strasbourg, France
| | - Thomas J Bach
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, 12 rue du Général Zimmer, F-67084 Strasbourg, France
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Park JH, Woo YM, Youm EM, Hamad N, Won HH, Naka K, Park EJ, Park JH, Kim HJ, Kim SH, Kim HJ, Ahn JS, Sohn SK, Moon JH, Jung CW, Park S, Lipton JH, Kimura S, Kim JW, Kim DDH. HMGCLL1 is a predictive biomarker for deep molecular response to imatinib therapy in chronic myeloid leukemia. Leukemia 2018; 33:1439-1450. [PMID: 30555164 PMCID: PMC6756062 DOI: 10.1038/s41375-018-0321-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 09/27/2018] [Accepted: 10/16/2018] [Indexed: 12/13/2022]
Abstract
Achieving a deep molecular response (DMR) to tyrosine kinase inhibitor (TKI) therapy for chronic myeloid leukemia (CML) remains challenging and at present, there is no biomarker to predict DMR in this setting. Herein, we report that an HMGCLL1 genetic variant located in 6p12.1 can be used as a predictive genetic biomarker for intrinsic sensitivity to imatinib (IM) therapy. We measured DMR rate according to HMGCLL1 variant in a discovery set of CML patients (n = 201) and successfully replicated it in a validation set (n = 270). We also investigated the functional relevance of HMGCLL1 blockade with respect to response to TKI therapy and showed that small interfering RNA mediated blockade of HMGCLL1 isoform 3 results in significant decrease in viability of BCR-ABL1-positive cells including K562, CML-T1 or BaF3 cell lines with or without ABL1 kinase domain mutations such as T315I mutation. Decreased cell viability was also demonstrated in murine CML stem cells and human hematopoietic progenitor cells. RNA sequencing showed that blockade of HMGCLL1 was associated with G0/G1 arrest and the cell cycle. In summary, the HMGCLL1 gene polymorphism is a novel genetic biomarker for intrinsic sensitivity to IM therapy in CML patients that predicts DMR in this setting.
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Affiliation(s)
- Jong-Ho Park
- Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul, Korea
| | - Young Min Woo
- Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul, Korea
| | - Emilia Moonkyung Youm
- Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul, Korea
| | - Nada Hamad
- Department of Haematology, St Vincent's Hospital, University of New South Wales, Sydney, Australia
| | - Hong-Hee Won
- Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Samsung Medical Center, Seoul, Korea
| | - Kazuhito Naka
- Department of Stem Cell Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan
| | - Eun-Ju Park
- Research Institute for Future Medicine, Samsung Medical Center, Seoul, Korea
| | - June-Hee Park
- Research Institute for Future Medicine, Samsung Medical Center, Seoul, Korea
| | - Hee-Jin Kim
- Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Sun-Hee Kim
- Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Hyeoung-Joon Kim
- Department of Hematology-Oncology, Chonnam National University Hwasun Hospital, Hwasun, Korea
| | - Jae Sook Ahn
- Department of Hematology-Oncology, Chonnam National University Hwasun Hospital, Hwasun, Korea
| | - Sang Kyun Sohn
- Department of Hematology/Oncology, Kyungpook National University Hospital, Daegu, Korea
| | - Joon Ho Moon
- Department of Hematology/Oncology, Kyungpook National University Hospital, Daegu, Korea
| | - Chul Won Jung
- Department of Hematology/Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Silvia Park
- Department of Hematology/Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Jeffrey H Lipton
- Department of Medical Oncology & Hematology, Princess Margaret Cancer Centre, University Health Network, University of Toronto, Toronto, Canada
| | - Shinya Kimura
- Division of Hematology, Respiratory Medicine and Oncology, Department of Internal Medicine, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga, 849-8501, Japan
| | - Jong-Won Kim
- Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul, Korea. .,Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Samsung Medical Center, Seoul, Korea. .,Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
| | - Dennis Dong Hwan Kim
- Department of Medical Oncology & Hematology, Princess Margaret Cancer Centre, University Health Network, University of Toronto, Toronto, Canada
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Fang Q, Figueredo Benedetti AF, Ma Q, Gregory L, Li JZ, Dattani M, Sadeghi-Nejad A, Arnhold IJ, de Mendonça BB, Camper SA, Carvalho LR. HESX1 mutations in patients with congenital hypopituitarism: variable phenotypes with the same genotype. Clin Endocrinol (Oxf) 2016; 85:408-14. [PMID: 27000987 PMCID: PMC4988903 DOI: 10.1111/cen.13067] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 02/22/2016] [Accepted: 03/16/2016] [Indexed: 02/01/2023]
Abstract
INTRODUCTION Mutations in the transcription factor HESX1 can cause isolated growth hormone deficiency (IGHD) or combined pituitary hormone deficiency (CPHD) with or without septo-optic dysplasia (SOD). So far there is no clear genotype-phenotype correlation. PATIENTS AND RESULTS We report four different recessive loss-of-function mutations in three unrelated families with CPHD and no midline defects or SOD. A homozygous p.R160C mutation was found by Sanger sequencing in two siblings from a consanguineous family. These patients presented with ACTH, TSH and GH deficiencies, severe anterior pituitary hypoplasia (APH) or pituitary aplasia (PA) and normal posterior pituitary. The p.R160C mutation was previously reported in a case with SOD, CPHD and ectopic posterior pituitary (EPP). Using exome sequencing, a homozygous p.I26T mutation was found in a Brazilian patient born to consanguineous parents. This patient had evolving CPHD, normal ACTH, APH and normal posterior pituitary (NPP). A previously reported patient homozygous for p.I26T had evolving CPHD and EPP. Finally, we identified compound heterozygous mutations in HESX1, p.[R159W];[R160H], in a patient with PA and CPHD. We showed that both of these mutations abrogate the ability of HESX1 to repress PROP1-mediated transcriptional activation. A patient homozygous for p.R160H was previously reported in a patient with CPHD, EPP, APH. CONCLUSION These three examples demonstrate that HESX1 mutations cause variable clinical features in patients, which suggests an influence of modifier genes or environmental factors on the phenotype.
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Affiliation(s)
- Qing Fang
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Anna Flavia Figueredo Benedetti
- Division of Endocrinology, Unit of Endocrinology and Development, Laboratory of Hormones and Molecular Genetics, Clinical Hospital of the Faculty of Medicine of the University of São Paulo, São Paulo, Brazil
| | - Qianyi Ma
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Louise Gregory
- Developmental Endocrinology Research Group, Section of Genetics and Epigenetics in Health and Disease, Genetics and Genomic Medicine Programme, University College London, Institute of Child Health, London, UK
| | - Jun Z. Li
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Mehul Dattani
- Developmental Endocrinology Research Group, Section of Genetics and Epigenetics in Health and Disease, Genetics and Genomic Medicine Programme, University College London, Institute of Child Health, London, UK
| | - Abdollah Sadeghi-Nejad
- Division of Pediatric Endocrinology, Floating Hospital for Children at Tufts Medical Center, Tufts University School of Medicine, Boston, MA, USA
| | - Ivo J.P. Arnhold
- Division of Endocrinology, Unit of Endocrinology and Development, Laboratory of Hormones and Molecular Genetics, Clinical Hospital of the Faculty of Medicine of the University of São Paulo, São Paulo, Brazil
| | - Berenice Bilharinho de Mendonça
- Division of Endocrinology, Unit of Endocrinology and Development, Laboratory of Hormones and Molecular Genetics, Clinical Hospital of the Faculty of Medicine of the University of São Paulo, São Paulo, Brazil
| | - Sally A. Camper
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, USA
- Correspondence should be addressed to: Sally A. Camper, Ph.D., Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI 48109-5618, USA, Fax: 1-734-763-3784, , Luciani R. Carvalho, M.D., Ph.D., Endocrinology Discipline of Internal Medicine Department, University of Sao Paulo Medical School, Sao Paulo, Brazil, Fax: 55-11-2661-7519,
| | - Luciani R. Carvalho
- Division of Endocrinology, Unit of Endocrinology and Development, Laboratory of Hormones and Molecular Genetics, Clinical Hospital of the Faculty of Medicine of the University of São Paulo, São Paulo, Brazil
- Correspondence should be addressed to: Sally A. Camper, Ph.D., Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI 48109-5618, USA, Fax: 1-734-763-3784, , Luciani R. Carvalho, M.D., Ph.D., Endocrinology Discipline of Internal Medicine Department, University of Sao Paulo Medical School, Sao Paulo, Brazil, Fax: 55-11-2661-7519,
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Wang XL, Hu ZY, You CX, Kong XZ, Shi XP. Subcellular localization and vacuolar targeting of sorbitol dehydrogenase in apple seed. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2013; 210:36-45. [PMID: 23849111 DOI: 10.1016/j.plantsci.2013.04.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 04/21/2013] [Accepted: 04/24/2013] [Indexed: 06/02/2023]
Abstract
Sorbitol is the primary photosynthate and translocated carbohydrate in fruit trees of the Rosaceae family. NAD(+)-dependent sorbitol dehydrogenase (NAD-SDH, EC 1.1.1.14), which mainly catalyzes the oxidation of sorbitol to fructose, plays a key role in regulating sink strength in apple. In this study, we found that apple NAD-SDH was ubiquitously distributed in epidermis, parenchyma, and vascular bundle in developing cotyledon. NAD-SDH was localized in the cytosol, the membranes of endoplasmic reticulum and vesicles, and the vacuolar lumen in the cotyledon at the middle stage of seed development. In contrast, NAD-SDH was mainly distributed in the protein storage vacuoles in cotyledon at the late stage of seed development. Sequence analysis revealed there is a putative signal peptide (SP), also being predicated to be a transmembrane domain, in the middle of proteins of apple NAD-SDH isoforms. To investigate whether the putative internal SP functions in the vacuolar targeting of NAD-SDH, we analyzed the localization of the SP-deletion mutants of MdSDH5 and MdSDH6 (two NAD-SDH isoforms in apple) by the transient expression system in Arabidopsis protoplasts. MdSDH5 and MdSDH6 were not localized in the vacuoles after their SPs were deleted, suggesting the internal SP functions in the vacuolar targeting of apple NAD-SDH.
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Affiliation(s)
- Xiu-Ling Wang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian 271018, China.
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Puisac B, Teresa-Rodrigo ME, Arnedo M, Gil-Rodríguez MC, Pérez-Cerdá C, Ribes A, Pié A, Bueno G, Gómez-Puertas P, Pié J. Analysis of aberrant splicing and nonsense-mediated decay of the stop codon mutations c.109G>T and c.504_505delCT in 7 patients with HMG-CoA lyase deficiency. Mol Genet Metab 2013; 108:232-40. [PMID: 23465862 DOI: 10.1016/j.ymgme.2013.01.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 01/25/2013] [Indexed: 12/13/2022]
Abstract
Eukaryotic cells can be protected against mutations that generate stop codons by nonsense-mediated mRNA decay (NMD) and/or nonsense-associated altered splicing (NAS). However, the processes are only partially understood and do not always occur. In this work, we study these phenomena in the stop codon mutations c.109G>T (p.Glu37*) and c.504_505delCT; the second and third most frequent mutations in HMG-CoA lyase deficiency (MIM #246450). The deficiency affects the synthesis of ketone bodies and produces severe disorders during early childhood. We used a minigene approach, real-time quantitative PCR and the inhibition of NMD by puromycin treatment, to study the effect of stop codons on splicing (NAS) and NMD in seven patients. Surprisingly, none of the stop codons studied appears to be the direct cause of aberrant splicing. In the mutation c.109G>T, the splicing is due to the base change G>T at position 109, which is critical and cannot be explained by disruption of exonic splicing enhancer (ESE) elements, by the appearance of exonic splicing silencer (ESS) elements which were predicted by bioinformatic tools or by the stop codons. Moreover, the mutation c.504_505delCT produces two mRNA transcripts both with stop codons that generate simultaneous NMD phenomena. The effects of the mutations studied on splicing seemed to be similar in all the patients. Furthermore, we report a Spanish patient with 3-hydroxy-3-methylglutaric aciduria and a novel missense mutation: c.825C>G (p.Asn275Lys).
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Affiliation(s)
- Beatriz Puisac
- Unit of Clinical Genetics and Functional Genomics, Department of Pharmacology-Physiology, School of Medicine, University of Zaragoza, E-50009 Zaragoza, Spain
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