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Rani R, Syngkli S, Nongkhlaw J, Das B. Expression and characterisation of human glycerol kinase: the role of solubilising agents and molecular chaperones. Biosci Rep 2023; 43:BSR20222258. [PMID: 37021775 PMCID: PMC10130975 DOI: 10.1042/bsr20222258] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 03/11/2023] [Accepted: 04/06/2023] [Indexed: 04/07/2023] Open
Abstract
BACKGROUND Glycerol kinase (GK; EC 2.7.1.30) facilitates the entry of glycerol into pathways of glucose and triglyceride metabolism and may play a potential role in Type 2 diabetes mellitus (T2DM). However, the detailed regulatory mechanisms and structure of the human GK are unknown. METHODS The human GK gene was cloned into the pET-24a(+) vector and over-expressed in Escherichia coli BL21 (DE3). Since the protein was expressed as inclusion bodies (IBs), various culture parameters and solubilising agents were used but they did not produce bioactive His-GK; however, co-expression of His-GK with molecular chaperones, specifically pKJE7, achieved expression of bioactive His-GK. The overexpressed bioactive His-GK was purified using coloumn chromatography and characterised using enzyme kinetics. RESULTS The overexpressed bioactive His-GK was purified apparently to homogeneity (∼295-fold) and characterised. The native His-GK was a dimer with a monomeric molecular weight of ∼55 kDa. Optimal enzyme activity was observed in TEA buffer (50 mM) at 7.5 pH. K+ (40 mM) and Mg2+ (2.0 mM) emerged as prefered metal ions for His-GK activity with specific activity 0.780 U/mg protein. The purified His-GK obeyed standard Michaelis-Menten kinetics with Km value of 5.022 µM (R2=0.927) for its substrate glycerol; whereas, that for ATP and PEP was 0.767 mM (R2=0.928) and 0.223 mM (R2=0.967), respectively. Other optimal parameters for the substrate and co-factors were also determined. CONCLUSION The present study demonstrates that co-expression of molecular chaperones assists with the expression of bioactive human GK for its characterisation.
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Affiliation(s)
- Riva Mary Rani
- Biological Chemistry Laboratory, Department of Zoology, North-Eastern Hill University, Shillong 793022, India
| | - Superior Syngkli
- Biological Chemistry Laboratory, Department of Zoology, North-Eastern Hill University, Shillong 793022, India
| | - Joplin Nongkhlaw
- Biological Chemistry Laboratory, Department of Zoology, North-Eastern Hill University, Shillong 793022, India
| | - Bidyadhar Das
- Biological Chemistry Laboratory, Department of Zoology, North-Eastern Hill University, Shillong 793022, India
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2
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Miao L, Su F, Yang Y, Liu Y, Wang L, Zhan Y, Yin R, Yu M, Li C, Yang X, Ge C. Glycerol kinase enhances hepatic lipid metabolism by repressing nuclear receptor subfamily 4 group A1 in the nucleus. Biochem Cell Biol 2020; 98:370-377. [DOI: 10.1139/bcb-2019-0317] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Glycerol kinase (GYK) plays a critical role in hepatic metabolism by converting glycerol to glycerol 3-phosphate in an ATP-dependent reaction. GYK isoform b is the only glycerol kinase present in whole cells, and has a non-enzymatic moonlighting function in the nucleus. GYK isoform b acts as a co-regulator of nuclear receptor subfamily 4 group A1 (NR4A1) and participates in the regulation of hepatic glucose metabolism by protein–protein interaction with NR4A1. Herein, GYK expression was found to upregulate the expression of NR4A1-mediated lipid metabolism-related genes (SREBP1C, FASN, ACACA, and GPAM) in HEK293T and L02 cells, and in mouse in vivo studies. GYK expression increased blood levels of cholesterol, triglyceride, and high-density lipoprotein cholesterol, but not low-density lipoprotein cholesterol levels. It enhanced the transcriptional activity of Nr4a1 target genes by negatively cooperating with NR4A1 and its enzymatic activity or by other undefined moonlighting functions. This enhancement was observed in both normal and diabetic mice. We also found a feed-forward regulation loop between GYK and NR4A1, serving as part of a GYK-NR4A1 regulatory mechanism in hepatic metabolism. Thus, GYK regulates the effect of NR4A1 on hepatic lipid metabolism in normal and diabetic mice, partially through the cooperation of GYK and NR4A1.
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Affiliation(s)
- Lili Miao
- Department of Experimental Hematology and Biochemistry, Beijing Institute of Radiation Medicine, Beijing 100850, China
- Graduate School of Anhui Medical University, Hefei 230032, China
| | - Fei Su
- Department of Experimental Hematology and Biochemistry, Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Yongsheng Yang
- Department of Experimental Hematology and Biochemistry, Beijing Institute of Radiation Medicine, Beijing 100850, China
- Institute of Acu-moxibustion, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Yue Liu
- Department of Experimental Hematology and Biochemistry, Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Lei Wang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Lifeomics, Beijing 102206, China
| | - Yiqun Zhan
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Lifeomics, Beijing 102206, China
| | - Ronghua Yin
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Lifeomics, Beijing 102206, China
| | - Miao Yu
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Lifeomics, Beijing 102206, China
| | - Changyan Li
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Lifeomics, Beijing 102206, China
| | - Xiaoming Yang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Lifeomics, Beijing 102206, China
| | - Changhui Ge
- Department of Experimental Hematology and Biochemistry, Beijing Institute of Radiation Medicine, Beijing 100850, China
- Graduate School of Anhui Medical University, Hefei 230032, China
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3
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Miao L, Yang Y, Liu Y, Lai L, Wang L, Zhan Y, Yin R, Yu M, Li C, Yang X, Ge C. Glycerol kinase interacts with nuclear receptor NR4A1 and regulates glucose metabolism in the liver. FASEB J 2019; 33:6736-6747. [PMID: 30821173 DOI: 10.1096/fj.201800945rr] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Glycerol kinase (Gyk), consisting of 4 isoforms, plays a critical role in metabolism by converting glycerol to glycerol 3-phosphate in an ATP-dependent reaction. Only Gyk isoform b is present in whole cells, but its function in the nucleus remains elusive. Previous studies have shown that nuclear orphan receptor subfamily 4 group A member (NR4A)-1 is an important regulator of hepatic glucose homeostasis and lipid metabolism in adipose tissue. We aimed to elucidate the functional interaction between nuclear Gyk and NR4A1 during hepatic gluconeogenesis in the unfed state and diabetes. We identified nuclear Gyk as a novel corepressor of NR4A1 in the liver; moreover, this recruitment was dependent on the C-terminal ligand-binding domain instead of the N-terminal activation function 1 domain, which interacts with other NR4A1 coregulators. NR4A1 transcriptional activity was inhibited by Gyk via protein-protein interaction but not enzymatic activity. Moreover, Gyk overexpression suppressed NR4A1 ability to regulate the expression of target genes involved in hepatic gluconeogenesis in vitro and in vivo as well as blood glucose regulation, which was observed in both unfed and diabetic mice. These results highlight the moonlighting function of nuclear Gyk, which was found to act as a coregulator of NR4A1, participating in the regulation of hepatic glucose homeostasis in the unfed state and diabetes.-Miao, L., Yang, Y., Liu, Y., Lai, L., Wang, L., Zhan, Y., Yin, R., Yu, M., Li, C., Yang, X., Ge, C. Glycerol kinase interacts with nuclear receptor NR4A1 and regulates glucose metabolism in the liver.
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Affiliation(s)
- Lili Miao
- Beijing Institute of Radiation Medicine, Beijing, China.,Graduate School, Anhui Medical University, Hefei, China
| | - Yongsheng Yang
- Institute of AcuMoxibustion, China Academy of Chinese Medical Sciences, Beijing, China.,State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Lifeomics, Beijing, China; and
| | - Yue Liu
- Beijing Institute of Radiation Medicine, Beijing, China.,Department of Pharmaceutical Engineering, Tianjin University, Tianjin, China
| | - Lili Lai
- Beijing Institute of Radiation Medicine, Beijing, China.,Graduate School, Anhui Medical University, Hefei, China
| | - Lei Wang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Lifeomics, Beijing, China; and.,Department of Pharmaceutical Engineering, Tianjin University, Tianjin, China
| | - Yiqun Zhan
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Lifeomics, Beijing, China; and
| | - Ronghua Yin
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Lifeomics, Beijing, China; and
| | - Miao Yu
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Lifeomics, Beijing, China; and
| | - Changyan Li
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Lifeomics, Beijing, China; and
| | - Xiaoming Yang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Lifeomics, Beijing, China; and
| | - Changhui Ge
- Beijing Institute of Radiation Medicine, Beijing, China.,Graduate School, Anhui Medical University, Hefei, China
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4
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McCabe ERB. American Pediatric Society presidential address 2007: Robust complex networks in health, disease and international pediatric research. Pediatr Res 2007; 62:374-9. [PMID: 17712287 DOI: 10.1203/pdr.0b013e3181515110] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Edward R B McCabe
- Mattel Children's Hospital, The University of California-Los Angeles, Los Angeles, CA 90095, USA.
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5
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Klein RD, Thorland EC, Gonzales PR, Beck PA, Dykas DJ, McGrath JM, Bale AE. A multiplex assay for the detection and mapping of complex glycerol kinase deficiency. Clin Chem 2006; 52:1864-70. [PMID: 16887896 DOI: 10.1373/clinchem.2006.072397] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Glycerol kinase deficiency (GKD) is an X-linked recessive disorder that presents in both isolated and complex forms. The contiguous deletion that leads to GKD also commonly affects NR0B1 (DAX1), the gene associated with adrenal hypoplasia congenita, and DMD, the Duchenne muscular dystrophy gene. Molecular testing to delineate this deletion is expensive and has only limited availability. METHODS We designed a multiplex PCR assay for the detection and mapping of a contiguous deletion potentially affecting the IL1RAPL1, NR0B1, GK, and DMD genes in a 29-month-old male patient with GKD. RESULTS Multiplex PCR detected a contiguous deletion that involved the IL1RAPL1, NR0B1, GK, and DMD genes. Although the patient had a creatine kinase concentration within the reference interval, further mapping with PCR revealed that exon 74 was the last intact exon at the 3' end of the DMD gene. CONCLUSIONS Multiplex PCR is an effective and inexpensive way to detect and map the contiguous deletion in cases of complex GKD. The extension of a deletion to include DMD exon 75 in a patient with a creatine kinase concentration within the reference interval suggests that this region of the gene may not be essential for protein function.
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Affiliation(s)
- Roger D Klein
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55901, USA.
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6
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Martinez Agosto JA, McCabe ER. Conserved family of glycerol kinase loci in Drosophila melanogaster. Mol Genet Metab 2006; 88:334-45. [PMID: 16545593 PMCID: PMC2807631 DOI: 10.1016/j.ymgme.2006.01.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2006] [Accepted: 01/10/2006] [Indexed: 10/24/2022]
Abstract
Glycerol kinase (GK) is an enzyme that catalyzes the formation of glycerol 3-phosphate from ATP and glycerol, the rate-limiting step in glycerol utilization. We analyzed the genome of the model organism Drosophila melanogaster and identified five GK orthologs, including two loci with sequence homology to the mammalian Xp21 GK protein. Using a combination of sequence analysis and evolutionary comparisons of orthologs between species, we characterized functional domains in the protein required for GK activity. Our findings include additional conserved domains that suggest novel nuclear and mitochondrial functions for glycerol kinase in apoptosis and transcriptional regulation. Investigation of GK function in Drosophila will inform us about the role of this enzyme in development and will provide us with a tool to examine genetic modifiers of human metabolic disorders.
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Affiliation(s)
- Julian A. Martinez Agosto
- Department of Pediatrics, David Geffen School of Medicine at UCLA; and Mattel Children’s Hospital at UCLA, USA
| | - Edward R.B. McCabe
- Department of Pediatrics, David Geffen School of Medicine at UCLA; and Mattel Children’s Hospital at UCLA, USA
- Department of Human Genetics, David Geffen School of Medicine at UCLA; UCLA Molecular Biology Institute; and UCLA Biomedical Engineering Interdepartmental Training Program, USA
- Corresponding author. Fax: +1 310 267 2045. (E.R.B. McCabe)
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7
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McCabe LL, McCabe ERB. Complexity in genetic diseases: how patients inform the science by ignoring the dogma. Am J Med Genet A 2006; 140:160-1. [PMID: 16353257 DOI: 10.1002/ajmg.a.31032] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Linda L McCabe
- Mattel Children's Hospital at UCLA, Los Angeles, California 90095-1752, USA.
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8
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Kuwada N, Nagano K, MacLennan N, Havens J, Kumar M, Dipple KM, McCabe ERB. Gene therapy for murine glycerol kinase deficiency: Importance of murine ortholog. Biochem Biophys Res Commun 2005; 335:247-55. [PMID: 16105550 DOI: 10.1016/j.bbrc.2005.07.066] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2005] [Accepted: 07/13/2005] [Indexed: 10/25/2022]
Abstract
A glycerol kinase (Gyk) knock-out (KO) mouse model permits improved understanding of glycerol kinase (GK) deficiency (GKD) pathogenesis, however, early death of affected mice limits its utility. The purpose of this work was to delay death of affected males to investigate thoroughly their phenotypes. An adenoviral vector carrying the human (Adeno-XGK) or mouse (Adeno-XGyk) GK gene was injected into KO mice within 24 h of birth. Adeno-XGK did not change KO mouse survival time despite liver GK activity greater than 100% of wild type. However, Adeno-XGyk improved KO mouse survival time greater than two-fold. These investigations demonstrate that gene replacement therapy for Gyk KO mice is more efficacious using murine Gyk than human GK. These studies expand our understanding of GKD pathogenesis in the murine model, and show that while murine GKD is more severe than in humans, GKD mice have similar metabolic disturbances to affected humans with hypoglycemia and acidemia.
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Affiliation(s)
- N Kuwada
- Department of Pediatrics, David Geffen School of Medicine at UCLA and Mattel Children's Hospital at UCLA, Los Angeles, CA 90095, USA
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9
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Ohira RH, Dipple KM, Zhang YH, McCabe ERB. Human and murine glycerol kinase: influence of exon 18 alternative splicing on function. Biochem Biophys Res Commun 2005; 331:239-46. [PMID: 15845384 DOI: 10.1016/j.bbrc.2005.03.143] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2005] [Indexed: 01/18/2023]
Abstract
Glycerol kinase (GK) is a key enzyme in glycerol metabolism with two alternatively spliced forms-one with an 87bp insertion corresponding to exon 18 (GK+EX18), and one lacking exon 18 (GK-EX18). We report the expression of GK+/-EX18 in various tissues and cell lines, as well as their enzymatic characteristics and subcellular localization. RT-PCR revealed differential expression in tissues and cell lines. Northern blot analysis revealed that both forms of the murine ortholog, Gyk, were highly expressed in murine heart and increased during embryonic development. K(m) values for glycerol for GK+/-EX18 were not significantly different, although GK-EX18 had a higher V(max) for glycerol. GK-EX18 had a lower K(m) and V(max) for ATP than GK+EX18. Immunofluorescence experiments showed that GK+EX18 co-localized to the mitochondria and the perinuclear region while GK-EX18 had a diffuse expression pattern. These data suggest specific and divergent roles for GK+EX18 and GK-EX18 in cellular metabolism and development.
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Affiliation(s)
- Riki H Ohira
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
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10
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Abstract
Genetic factors have an important role in the aetiology of mental retardation. However, their contribution is often underestimated because in developed countries, severely affected patients are mainly sporadic cases and familial cases are rare. X-chromosomal mental retardation is the exception to this rule, and this is one of the reasons why research into the genetic and molecular causes of mental retardation has focused almost entirely on the X-chromosome. Here, we review the remarkable recent progress in this field, its promise for understanding neural function, learning and memory, and the implications of this research for health care.
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Affiliation(s)
- H-Hilger Ropers
- Max-Planck-Institute for Molecular Genetics, Ihnestrasse 73, D-14195 Berlin, Germany.
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11
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Sjarif DR, Hellerud C, van Amstel JKP, Kleijer WJ, Sperl W, Lacombe D, Sass JO, Beemer FA, Duran M, Poll-The BT. Glycerol kinase deficiency: residual activity explained by reduced transcription and enzyme conformation. Eur J Hum Genet 2004; 12:424-32. [PMID: 15026783 DOI: 10.1038/sj.ejhg.5201172] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Four unrelated patients with glyceroluria ranging from 7 to 170 mmol/l were studied. The activity of glycerol kinase (GK) in cultured fibroblasts was determined with a specific enzyme assay and with two indirect methods, that is, incorporation into macromolecules of [(14)C] from [(14)C]glycerol and its oxidation to [(14)C]CO(2). Exon amplification and RT-PCR were used to identify mutations. In patient 1, with low activity in all three assays, we identified a c.1194A>C (E398D) missense mutation. In patient 2 with a considerable activity of the GK enzyme (22% of reference), oxidation to [(14)C]CO(2) (37%) and a high incorporation of [(14)C] into macromolecules (92%), we identified a c.182T>C (L61P) mutation that causes the enzyme to have a higher K(m) for glycerol ( approximately 300 microM) than normals (2-8 microM). In patient 3, the GK activity estimated by the three different methods ranged from 16 to 22% of reference. Analysis of mRNA from the GK gene revealed three alternatively spliced transcripts. A mutation in intron 3 (g.16835G>A) resulted in an insertion of a cryptic exon between exon 2 or 3 and exon 4. Patient 4 with minor glyceroluria (7 mmol/l) and normal plasma glycerol concentration had normal activity with all three assay methods, thus excluding GK deficiency (GKD) as a cause of slight glyceroluria. To evaluate fully patients with glyceroluria, one needs to measure the GK activity and relate this and the clinical data to genetic findings. Residual enzyme activities in cultured fibroblasts can be found in GKD patients with severe clinical symptoms.
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Affiliation(s)
- Damayanti R Sjarif
- Department of Medical Genetics, University Medical Center, Utrecht, The Netherlands
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12
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Sjarif DR, Ploos van Amstel JK, Duran M, Beemer FA, Poll-The BT. Isolated and contiguous glycerol kinase gene disorders: a review. J Inherit Metab Dis 2000; 23:529-47. [PMID: 11032329 DOI: 10.1023/a:1005660826652] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Glycerol kinase deficiency (GKD) is an X-linked recessive disorder. There are two types. an isolated form and a complex form. We review the clinical, biochemical and molecular genetic features of GKD. The clinical and biochemical phenotype of isolated GKD may vary from a life-threatening childhood metabolic crisis to asymptomatic adult 'pseudohypertriglyceridaemia', resulting from hyperglycerolaemia. To date 38 patients from 24 families with isolated GKD have been reported. At least 7 of these patients had a metabolic crisis during a catabolic condition. The complex GKD is an Xp21 contiguous gene syndrome involving the glycerol kinase locus together with the adrenal hypoplasia congenita (AHC) or Duchenne muscular dystrophy (DMD) loci or both. Clinical features of a patient with complex GKD depend on the loci that are involved. Approximately 100 patients from 78 families with a complex GKD have been reported. Seventeen patients with complex GKD (AHC-GKD-DMD or AHC-GKD) died in the neonatal period or early childhood because of unrecognized or inappropriate management of adrenal dysfunction. Since the outcome of the crisis in GKD is highly dependent on the physicians' knowledge of the disease, we devised an algorithmic approach to the diagnosis. From molecular genetic investigations of isolated GKD, 7 missense mutations, 2 splice site mutations, I nonsense mutation, 1 Alu Sx insertion and 2 small deletions were reported for isolated GKD in 13 unrelated families. In 4 families consisting of more than one patient with the same biochemical and genetic defect, the phenotypic variability of the isolated GKD was remarkable. The clinical variability in isolated GKD cannot be explained by biochemical or by molecular heterogeneity. Isolated GKD patients showed a tendency towards hypoglycaemia with hyperketonaemia; whether the clinical symptoms of GKD are caused by dysfunction of gluconeogenesis and/or ketolysis needs to be investigated further.
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Affiliation(s)
- D R Sjarif
- Department of Pediatrics/Metabolic Diseases, University Medical Center Utrecht, The Netherlands
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13
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Sargent CA, Kidd A, Moore S, Dean J, Besley GT, Affara NA. Five cases of isolated glycerol kinase deficiency, including two families: failure to find genotype:phenotype correlation. J Med Genet 2000; 37:434-41. [PMID: 10851254 PMCID: PMC1734616 DOI: 10.1136/jmg.37.6.434] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Little is understood of the genotype/phenotype correlations in X linked glycerol kinase deficiency (GKD) where most cases are caused by extensive deletions of Xp21, which often include genes flanking the GK locus. Few cases of isolated GKD have been investigated where the phenotype is not influenced by neighbouring genes. In this paper, we present the mutation data from four confirmed and one suspected case of non-deletion, isolated, X linked GKD and therefore extend the base of patients that can allow an assessment of genotype/phenotype correlations for this disease. The mutations found were two terminations leading to premature truncation of the GK polypeptide chain, one insertion, and an amino acid substitution. Phenotypic variation was observed in two families, where there was more than one affected subject carrying the same mutation, confirming previous studies that suggest there is no correlation between disease severity and genotype. Furthermore, the nature of the mutation in different families does not appear to influence the spectrum of phenotypic variation. In addition, one coding polymorphism in exon 3 has been found. The characterisation of the gene structure has been completed and shows that instead of 19 there are 21 exons.
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Affiliation(s)
- C A Sargent
- Human Molecular Genetics Group, University of Cambridge, Department of Pathology, Tennis Court Road, Cambridge CB2 1QP, UK
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14
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Zhang Y, Dipple KM, Vilain E, Huang BL, Finlayson G, Therrell BL, Worley K, Deininger P, McCabe ER. AluY insertion (IVS4-52ins316alu) in the glycerol kinase gene from an individual with benign glycerol kinase deficiency. Hum Mutat 2000; 15:316-23. [PMID: 10737976 DOI: 10.1002/(sici)1098-1004(200004)15:4<316::aid-humu3>3.0.co;2-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Glycerol kinase deficiency has three distinct forms: an isolated form which may be benign or symptomatic, and a complex form which is symptomatic and part of an Xp21 contiguous gene syndrome. Here we report the case of a male with benign isolated glycerol kinase deficiency who was incidentally identified after observation of pseudohypertriglyceridemia. DNA sequencing of this subject's glycerol kinase gene showed the insertion of an AluY sequence in intron 4 of the glycerol kinase gene. Although Alu insertions have been implicated in other diseases, and a closely related AluY element is found as an insert in the C1 inhibitor gene in patients with hereditary angioedema, this is the first case of glycerol kinase deficiency caused by an Alu insertion.
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Affiliation(s)
- Y Zhang
- Department of Pediatrics, Division of Genetics, Mattel Children's Hospital at UCLA, Los Angeles, CA 90095-1782, USA
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15
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Gaudet D, Arsenault S, Pérusse L, Vohl MC, St-Pierre J, Bergeron J, Després JP, Dewar K, Daly MJ, Hudson T, Rioux JD. Glycerol as a correlate of impaired glucose tolerance: dissection of a complex system by use of a simple genetic trait. Am J Hum Genet 2000; 66:1558-68. [PMID: 10736265 PMCID: PMC1378005 DOI: 10.1086/302903] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1999] [Accepted: 02/09/2000] [Indexed: 11/03/2022] Open
Abstract
Glycerol kinase (GK) represents the primary entry of glycerol into glucose and triglyceride metabolism. Impaired glucose tolerance (IGT) and hypertriglyceridemia are associated with an increased risk of diabetes mellitus and cardiovascular disease. The relationship between glycerol and the risk of IGT, however, is poorly understood. We therefore undertook the study of fasting plasma glycerol levels in a cohort of 1,056 unrelated men and women of French-Canadian descent. Family screening in the initial cohort identified 18 men from five families with severe hyperglycerolemia (values above 2.0 mmol/liter) and demonstrated an X-linked pattern of inheritance. Linkage analysis of the data from 12 microsatellite markers surrounding the Xp21.3 GK gene resulted in a peak LOD score of 3.46, centered around marker DXS8039. In addition, since all of the families originated in a population with a proven founder effect-the Saguenay Lac-St.-Jean region of Quebec-a common disease haplotype was sought. Indeed, a six-marker haplotype extending over a region of 5.5 cM was observed in all families. Resequencing of the GK gene in family members led to the discovery of a N288D missense mutation in exon 10, which resulted in the substitution of a highly conserved asparagine residue by a negatively charged aspartic acid. Although patients with the N288D mutation suffered from severe hyperglycerolemia, they were apparently otherwise healthy. The phenotypic analysis of the family members, however, showed that glycerol levels correlated with impaired glucose metabolism and body-fat distribution. We subsequently noted a substantial variation in glycerolemia in subjects of the initial cohort with normal plasma glycerol levels and demonstrated that this variance showed significant family resemblance. These results suggest a potentially important genetic connection between fasting glycerolemia and glucose homeostasis, not only in this X-linked deficiency but, potentially, in individuals within the "normal" range of plasma glycerol concentrations.
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Affiliation(s)
- D Gaudet
- Lipid Research Group, Chicoutimi Hospital, Chicoutimi, and Lipid Research Center, Laval University, Quebec, Canada. . ca
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Pan Y, Decker WK, Huq AH, Craigen WJ. Retrotransposition of glycerol kinase-related genes from the X chromosome to autosomes: functional and evolutionary aspects. Genomics 1999; 59:282-90. [PMID: 10444329 DOI: 10.1006/geno.1999.5874] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Glycerol kinase catalyzes the metabolism of endogenously derived and dietary glycerol. GyK is a member of a small group of kinases termed ambiquitous enzymes, which are found either in the cytosol or as membrane-bound complexes associated with the voltage-dependent anion channel of the mitochondrial outer membrane. In Homo sapiens, the GyK gene family consists of an X-encoded locus and several X-linked and autosomal intronless retroposons, which, apparently, comprise both functional genes and processed pseudogenes. To study the role of the autosomal genes in mammalian physiology, we have isolated two murine GyK-like genes, determined their structures and chromosomal locations, and examined their functions. These sequences are intronless retroposons, which appear to be paralogues of the X-encoded, brain-specific GyK isoform and are expressed only in the testes. Though both retrotransposition events appear to have occurred prior to the primate-rodent divergence of some 65-80 million years ago, only one of the retrotransposed murine gene sequences, based upon its chromosomal location, is conserved with modern H. sapiens. To test the hypothesis that the murine GyK-like genes encode functional GyK activity, transient transfection of the gene sequences into COS7 cells was carried out. While in vitro translation confirmed that the transcripts could direct the synthesis of proteins of the appropriate size, no GyK activity was detected. Such data suggest that the autosomal GyK-like genes have evolved novel, testis-specific functions. A comparison of the human and mouse GyK-like gene sequences demonstrates the evolutionary relationships between each autosomal isoform and its corresponding X-linked ancestral locus.
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Affiliation(s)
- Y Pan
- Department of Molecular and Human Genetics, Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA
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17
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Nachman MW, Bauer VL, Crowell SL, Aquadro CF. DNA variability and recombination rates at X-linked loci in humans. Genetics 1998; 150:1133-41. [PMID: 9799265 PMCID: PMC1460397 DOI: 10.1093/genetics/150.3.1133] [Citation(s) in RCA: 149] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We sequenced 11,365 bp from introns of seven X-linked genes in 10 humans, one chimpanzee, and one orangutan to (i) provide an average estimate of nucleotide diversity (pi) in humans, (ii) investigate whether there is variation in pi among loci, (iii) compare ratios of polymorphism to divergence among loci, and (iv) provide a preliminary test of the hypothesis that heterozygosity is positively correlated with the local rate of recombination. The average value for pi was low 0.063%, SE = 0.036%, about one order of magnitude smaller than for Drosophila melanogaster, the species for which the best data are available. Among loci, pi varied by over one order of magnitude. Statistical tests of neutrality based on ratios of polymorphism to divergence or based on the frequency spectrum of variation within humans failed to reject a neutral, equilibrium model. However, there was a positive correlation between heterozygosity and rate of recombination, suggesting that the joint effects of selection and linkage are important in shaping patterns of nucleotide variation in humans.
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Affiliation(s)
- M W Nachman
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona 85721, USA.
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18
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Peter M, Viemann M, Partsch CJ, Sippell WG. Congenital adrenal hypoplasia: clinical spectrum, experience with hormonal diagnosis, and report on new point mutations of the DAX-1 gene. J Clin Endocrinol Metab 1998; 83:2666-74. [PMID: 9709929 DOI: 10.1210/jcem.83.8.5027] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
X-linked congenital adrenal hypoplasia (AHC) is a rare developmental disorder of the human adrenal cortex and is caused by deletion or mutation of the DAX-1 gene, a recently discovered member of the nuclear hormone receptor superfamily. Hypogonadotropic hypogonadism is frequently associated with AHC. AHC occurs as part of a contiguous gene syndrome together with glycerol kinase deficiency (GKD) and Duchenne's muscular dystrophy. The present series, collected over the past 2 decades, includes 18 AHC boys from 16 families: 4 with AHC, GKD, and Duchenne's muscular dystrophy; 2 with AHC and GKD; and 12 with AHC (5 young adults with hypogonadotropic hypogonadism). Most of the boys presented with salt wasting and hyperpigmentation during the neonatal period. Plasma steroid determinations performed in the first weeks of life often showed confusing results, probably caused by steroids produced in the neonates' persisting fetocortex. Aldosterone deficiency usually preceded cortisol deficiency, which explains why the patients more often presented with salt-wasting rather than with hypoglycemic symptoms. An ACTH test was often necessary to detect cortisol deficiency in the very young infants. In some patients, serial testing was necessary to establish the correct diagnosis. In 4 boys studied during the first 3 months after birth, we found pubertal LH, FSH, and testosterone plasma levels indicating postnatal transient activation of the hypothalamic-pituitary-gonadal axis as in normal boys. Previous studies have shown that the DAX-1 gene is deleted in the AHC patients with a contiguous gene syndrome and is mutated in nondeletion patients. Most of the point mutations identified in AHC patients were frameshift mutations and stop mutations. In the 15 patients available for molecular analysis of the DAX-1 gene, there were large deletions in 6 patients and point mutations in another 7 patients. All of the point mutations identified in the present study resulted in a nonfunctional truncated DAX-1 protein. Two brothers with primary adrenal insufficiency and a medical history that strongly suggested AHC had no mutation in the DAX-1 gene. Thus, additional, as yet unknown genes must play a part in normal adrenal cortical development.
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Affiliation(s)
- M Peter
- Department of Pediatrics, Christian Albrechts University, Kiel, Germany
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19
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Sjarif DR, Sinke RJ, Duran M, Beemer FA, Kleijer WJ, Ploos van Amstel JK, Poll-The BT. Clinical heterogeneity and novel mutations in the glycerol kinase gene in three families with isolated glycerol kinase deficiency. J Med Genet 1998; 35:650-6. [PMID: 9719371 PMCID: PMC1051390 DOI: 10.1136/jmg.35.8.650] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Isolated glycerol kinase deficiency (GKD) is an X linked recessive disorder. The clinical and biochemical picture may vary from a childhood metabolic crisis to asymptomatic adult "pseudohypertriglyceridaemia", the result of hyperglycerolaemia. We performed glycerol kinase (GK) gene analysis to study the molecular heterogeneity and genotype-phenotype correlation in eight males from three families with isolated GKD. All patients had hyperglycerolaemia and glyceroluria. Four patients from two families were essentially free of symptoms. Three patients had gastrointestinal symptoms with ketoacidosis or hypoglycaemia or both. One patient had recurrent convulsions as the only acute sign, without evidence that it was correlated with a catabolic state. Fasting tests in two symptomatic patients of family 1 showed hyperketotic states, together with a tendency to hypoglycaemia. The diagnosis was confirmed by a defective 14C-glycerol incorporation into trichloroacetic acid precipitable macromolecules in intact skin fibroblasts. Mutation screening of the GK gene was performed by amplification and direct sequencing of exons using PCR. Three novel mutations were identified: (1) a deletion starting downstream of exon 9, extending to the 3' end of the gene; (2) a nonsense mutation R413X caused by a C1351T transition; and (3) a missense mutation W503R caused by a T1651C transition. In addition, we found differences from the reported sequence: (1) exon 9 actually consists of two exons, which consequently will change the number of GK gene exons from 19 to 20 exons, and (2) nucleotide differences in exon 19. So far, no genotype-phenotype correlation can be established in these GKD families.
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Affiliation(s)
- D R Sjarif
- University Children's Hospital Het Wilhelmina Kinderziekenhuis, Utrecht, The Netherlands
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20
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Huq AH, Lovell RS, Ou CN, Beaudet AL, Craigen WJ. X-linked glycerol kinase deficiency in the mouse leads to growth retardation, altered fat metabolism, autonomous glucocorticoid secretion and neonatal death. Hum Mol Genet 1997; 6:1803-9. [PMID: 9302256 DOI: 10.1093/hmg/6.11.1803] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Glycerol kinase is an X chromosome-encoded enzyme involved in the metabolism of endogenous and dietary glycerolipids. The physiological significance of its activity in mammals is not well understood. Glycerol kinase deficiency in humans occurs as an isolated enzyme deficiency or as part of a contiguous gene deletion syndrome in variable association with Duchenne muscular dystrophy and adrenal hypoplasia congenita. Isolated glycerol kinase deficiency has an inconstant phenotype, ranging from asymptomatic hyperglycerolemia to a severe metabolic disorder with growth and psychomotor retardation. Although intragenic mutations were reported recently, the pathophysiological basis for the phenotypic variability remains unknown. To understand better the physiological significance of glycerol kinase and the pathophysiology of its deficiency, we generated glycerol kinase-deficient mice by gene targeting. Mutant male mice appear normal at birth, but exhibit postnatal growth retardation, altered fat metabolism with profound hyperglycerolemia and elevated free fatty acids, autonomous glucocorticoid synthesis and death by 3-4 days of age. Heterozygous females are healthy and biochemically normal. The biochemical features observed in glycerol kinase-deficient mice provide the basis for further investigations into the pathogenesis of the human disorder.
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Affiliation(s)
- A H Huq
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
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21
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Guo W, Adams V, Mason J, McCabe ER. Identification of a ferritin light chain pseudogene near the glycerol kinase locus in Xp21 by cDNA amplification for identification of genomic expressed sequences. BIOCHEMICAL AND MOLECULAR MEDICINE 1997; 60:169-73. [PMID: 9169099 DOI: 10.1006/bmme.1996.2566] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We used cDNA amplification for identification of genomic expressed sequences (CAIGES) to identify genes in the glycerol kinase region of the human X chromosome. During these investigations we identified the sequence for a ferritin light chain (FTL) pseudogene in this portion of Xp21. A human liver cDNA library was amplified by vector primers, labeled, and hybridized to Southern blots of EcoRI-digested human genomic DNA from cosmids isolated from yeast artificial chromosomes in the glycerol kinase region of Xp21. A 3.1-kb restriction fragment hybridized with the cDNA library, was subcloned and sequenced, and a 440-bp intronless sequence was found with strong similarity to the FTL coding sequence. Therefore, the FTL pseudogene that had been mapped previously to Xp22.3-21.2 was localized specifically to the glycerol kinase region. The CAIGES method permits rapid screening of genomic material and will identify genomic sequences with similarities to genes expressed in the cDNA library used to probe the cloned genomic DNA, including pseudogenes.
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Affiliation(s)
- W Guo
- Department of Pediatrics, UCLA School of Medicine 90095-1752, USA
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22
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Blomquist HK, Dahl N, Gustafsson L, Hellerud C, Holme E, Holmgren G, Matsson L, von Zweigbergk M. Glycerol kinase deficiency in two brothers with and without clinical manifestations. Clin Genet 1996; 50:375-9. [PMID: 9007327 DOI: 10.1111/j.1399-0004.1996.tb02391.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We report two brothers with glycerol kinase deficiency (GKD). The older brother had serious clinical symptoms, mental and growth retardation, abnormal skeleton, spontaneous fractures and premature loss of abnormal teeth. He and his mother had low serum phosphate levels. He had elevated serum and urine glycerol levels and GKD was found in cultured fibroblasts. Prenatal diagnosis was performed in the second pregnancy. Glycerol kinase activity was considered normal in a chorionic villus sample of the foetus. After birth, it was found that the boy had elevated serum and urine glycerol levels. Enzymatic analysis in cultured fibroblasts revealed that this boy also had GKD, in spite of having no expression of the disease. Chromosomal analyses in the parents and both boys were normal. Major rearrangements or deletions were not detected in molecular studies of DNA from the two brothers. The hybridisation pattern was normal and no allelic loss was observed.
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23
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de Gouyon B, Chatterjee A, Monaco A, Quaderi N, Brown SD, Herman GE. Comparative mapping on the mouse X chromosome defines a myotubular myopathy equivalent region. Mamm Genome 1996; 7:575-9. [PMID: 8678976 DOI: 10.1007/s003359900172] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The gene for X-linked myotubular myopathy (MTM1) has been localized to a 300-kb critical region in human Xq28 between IDS and GABRA3. As part of an effort to clone this gene, we developed a YAC contig on the mouse X Chromosome (Chr) which includes loci homologous to those within the human MTM1 critical region. The murine contig consists of 18 YACs and spans 2.5-3.0 Mb. We have aligned the human and murine physical maps by isolating conserved mouse genomic fragments, including CpG islands and trapped exons. We believe that the simultaneous isolation of genes from both mouse and human and continued comparative mapping will prove helpful in the eventual identification of MTM1 and other genes in the region.
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Affiliation(s)
- B de Gouyon
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza 821T, Houston, TX 77030, USA
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24
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Abstract
A current list of all known forms of X-linked mental retardation (XLMR) and a slightly revised classification are presented. The number of known disorders has not increased because 6 disorders have been combined based on new molecular data or on clinical grounds and only 6 newly described XLMR disorders have been reported. Of the current 105 XLMR disorders, 34 have been mapped, and 18 disorders and 1 nonspecific XLMR (FRAXE) have been cloned. The number of families with nonspecific XLMR with a LOD score of > or = 2.0 has more than doubled, with 42 (including FRAXE) now being known. a summary of the localization of presumed nonspecific mental retardation (MR) genes from well-studied X-chromosomal translocations and deletions is also included. Only 10-12 nonoverlapping loci are required to explain all localizations of nonspecific MR from both approaches. These new trends mark the beginning of a significantly improved understanding of the role of genes on the X chromosome in producing MR. Continued close collaboration between clinical and molecular investigators will be required to complete the process.
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Affiliation(s)
- H A Lubs
- Department of Medical Genetics, University Hospital of Tromsø, Norway
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25
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Ahn J, Lüdecke HJ, Lindow S, Horton WA, Lee B, Wagner MJ, Horsthemke B, Wells DE. Cloning of the putative tumour suppressor gene for hereditary multiple exostoses (EXT1). Nat Genet 1995; 11:137-43. [PMID: 7550340 DOI: 10.1038/ng1095-137] [Citation(s) in RCA: 306] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Hereditary multiple exostoses is an autosomal dominant disorder that is characterized by short stature and multiple, benign bone tumours. In a majority of families, the genetic defect (EXT1) is linked to the Langer-Giedion syndrome chromosomal region in 8q24.1. From this region we have cloned and characterized a cDNA which spans chromosomal breakpoints previously identified in two multiple exostoses patients. Furthermore, the gene harbours frameshift mutations in affected members of two EXT1 families. The cDNA has a coding region of 2,238 bp with no apparent homology to other known gene sequences and thus its function remains elusive. However, recent studies in sporadic and exostosis-derived chondrosarcomas suggest that the 8q24.1-encoded EXT1 gene may have tumour suppressor function.
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Affiliation(s)
- J Ahn
- Department of Biology, University of Houston, Texas 77204-5513, USA
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26
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Worley KC, Lindsay EA, Bailey W, Wise J, McCabe ER, Baldini A. Rapid molecular cytogenetic analysis of X-chromosomal microdeletions: fluorescence in situ hybridization (FISH) for complex glycerol kinase deficiency. AMERICAN JOURNAL OF MEDICAL GENETICS 1995; 57:615-9. [PMID: 7573140 DOI: 10.1002/ajmg.1320570420] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Diagnosis of X-chromosomal microdeletions has relied upon the traditional methods of Southern blotting and DNA amplification, with carrier identification requiring time-consuming and unreliable dosage calculations. In this report, we describe rapid molecular cytogenetic identification of deleted DNA in affected males with the Xp21 contiguous gene syndrome (complex glycerol kinase deficiency, CGKD) and female carriers for this disorder. CGKD deletions involve the genes for glycerol kinase, Duchenne muscular dystrophy, and/or adrenal hypoplasia congenita. We report an improved method for diagnosis of deletions in individuals with CGKD and for identification of female carriers within their families, using fluorescence in situ hybridization (FISH) with a cosmid marker (cosmid 35) within the glycerol kinase gene. When used in combination with an Xq control probe, affected males demonstrate a single signal from the control probe, while female carriers demonstrate a normal chromosome with two signals, as well as a deleted chromosome with a single signal from the control probe. FISH analysis for CGKD provides the advantages of speed and accuracy for evaluation of submicroscopic X-chromosomal deletions, particularly in identification of female carriers. In addition to improving carrier evaluation, FISH will make prenatal diagnosis of CGKD more readily available.
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Affiliation(s)
- K C Worley
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
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27
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Worley KC, King KY, Chua S, McCabe ER, Smith RF. Identification of new members of a carbohydrate kinase-encoding gene family. J Comput Biol 1995; 2:451-8. [PMID: 8521274 DOI: 10.1089/cmb.1995.2.451] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
In a sequence database search using the human glycerol kinase-encoding sequence (HUMGLYKINB) as a query, we identified six previously unidentified carbohydrate kinase sequences. Five of the six newly identified sequences appear to be known types of carbohydrate kinases, four are glycerol kinases and one is a gluconokinase. The sixth newly identified sequence, the Caenorhabditis elegans gene, CER08D7.7-CEF59B2.1, shows similarity to the family of carbohydrate kinases including other glycerol kinases, xylulokinases, gluconokinases, ribulokinases, rhamnulokinases, and fucokinases. A phylogenetic comparison of this newly identified Caenorhabditis elegans gene with the other members of the carbohydrate kinase family demonstrated that this sequence cannot be assigned to one of the known classes of carbohydrate kinases.
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Affiliation(s)
- K C Worley
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
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28
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McCabe ER. Microcompartmentation of energy metabolism at the outer mitochondrial membrane: role in diabetes mellitus and other diseases. J Bioenerg Biomembr 1994; 26:317-25. [PMID: 8077185 DOI: 10.1007/bf00763103] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Complexes made up of the kinases, hexokinase and glycerol kinase, together with the outer mitochondrial membrane voltage-dependent anion channel (VDAC) protein, porin, and the inner mitochondrial membrane protein, the adenine nucleotide translocator, are involved in tumorigenesis, diabetes mellitus, and central nervous system function. Identification of these two mitochondrial membrane proteins, along with an 18 kD protein, as components of the peripheral benzodiazepine receptor, provides independent confirmation of the interaction of porin and the adenine nucleotide translocator to form functional contact sites between the inner and outer mitochondrial membranes. We suggest that these are dynamic structures, with channel conductances altered by the presence of ATP, and that ligand-mediated conformational changes in the porin-adenine nucleotide translocator complexes may be a general mechanism in signal transduction.
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Affiliation(s)
- E R McCabe
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030
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29
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Abstract
During the past year, improvements in the physical and genetic maps of the human genome, in combination with more efficient methods to isolate genes from cloned DNA, have made an increasing impact on the identification of disease genes. Sequence analysis of genomic DNA and the random sequencing and mapping of cDNA clones is helping to integrate the transcript map with the developing physical and genetic maps.
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Affiliation(s)
- A P Monaco
- Imperial Cancer Research Fund Laboratories, John Radcliffe Hospital, Headington, Oxford, UK
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