Down's syndrome: Abnormal neuromuscular junction in tongue of transgenic mice with elevated levels of human Cu/Zn-superoxide dismutase

Avraham, Karen B.; Schickler, Michael; Sapoznikov, Dan; Yarom, R.; Groner, Yoram

doi:10.1016/s0092-8674(88)91153-1

Cited by 211 publications

(108 citation statements)

References 19 publications

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“…1). Human and monkey SOD1 homodimeric enzymes were distinguishable after electrophoretic separation in nondenaturing polyacrylamide gels and in situ evaluation of activity (17,20,21) (Fig. 1A).…”

mentioning

confidence: 99%

Superoxide dismutase 1 with mutations linked to familial amyotrophic lateral sclerosis possesses significant activity.

Borchelt

Lee

Slunt

et al. 1994

Proc. Natl. Acad. Sci. U.S.A.

556

369

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Familial amyotrophic lateral sclerosis (FALS) has been linked to mutations in the homodimeric enzyme Cu/Zn superoxide dismutase 1 (SOD1). Assay by transient expression in primate cells of six FALS mutant enzymes revealed a continuum of enzymatic activity bounded by the enzyme carrying the mutation Gly-85 -Arg, which was inactive, and mutant enzyme G37R carrying the Gly-37 -> Arg change, which retained full specific activity but displayed a 2-fold reduction in polypeptide stability. (3,4,10,11). Initial studies of SOD1 activity in blood from six FALS cases reported 50-65% reductions in enzyme activity as a function of total protein (3,12,13), and it was suggested that FALS-linked mutations affect either enzyme activity or polypeptide stability, causing a nearly complete loss of function from the mutant allele. However, subsequent studies have reported that individuals heterozygous for a His-46 --Arg mutation, which lies in the active-site domain, possess blood enzyme activity levels that are 80%o of normal (6). One problem in interpreting these data is that others have demonstrated 2-to 3-fold variability in the SOD1 levels of circulating erythrocytes in normal individuals (11,12,14), casting doubt on the significance of blood SOD1 levels. In the present study, we examined mutant SOD1 subunits in nonerythroid cells, using lymphoblasts derived from FALS individuals and DNA transfection into primate cells, to determine the intrinsic specific activity and stability of wild-type and mutant Hu-SOD1 polypeptides. MATERIALS AND METHODSCloning and Mutagenesis of Human SOD) Genes. A cDNA copy of the human SOD) gene was obtained by reverse transcription-coupled polymerase chain reaction (PCR) amplification using primers (sense primer, GTCGACAAG-CATGGCCACGAAGGCCGTGTGC; antisense primer, CCGGTCGACAGGGAATGTIIATTGGGCGATCC) that contained terminal Sal I sites and converted sequences surrounding the start codon (underlined) from human GAGT-TATGG to mouse CAAGCAIQG, enhancing the consensus sequence for translation initiation (13). The PCR product was blunt-ligated into the Sma I site of Bluescript II KS(-) and was verified by sequencing. Mutations were engineered by oligonucleotide-directed mutagenesis by using a kit purchased from Amersham. The entire open reading frame of each mutant was confirmed by sequencing.Analysis of SOD1 Enzyme Activity. Wild-type and mutant SOD) genes were cloned into the vector pEF-BOS (15) and transfected transiently into COS-1 cells (16). After 48 h, cells were lysed by a freeze/thaw cycle in water, which was then adjusted to contain 0.125 M Tris chloride (pH 6.8), 20%o (vol/vol) glycerol, 0.025% bromophenol blue, and 0.1% Nonidet P-40. After centrifugation at 10,000 x g for 5 min, the supernatant was separated by electrophoresis on 7.5% polyacrylamide gels, and SOD1 activities were determined as described (17). The intensities of the SOD1 activity signals seen in our assay gels fall within a linear range bounded by 0.0625 ug and 2 pg of purified human erythrocyte SOD1.Calculation of SOD1 En...

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mentioning

confidence: 99%

Superoxide dismutase 1 with mutations linked to familial amyotrophic lateral sclerosis possesses significant activity.

Borchelt

Lee

Slunt

et al. 1994

Proc. Natl. Acad. Sci. U.S.A.

556

369

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“…Although over-expression of the human SOD protein in transgenic mice appears to be protective after ischemic injury and oxidative stress (33,34), these mice develop a phenotype that simulates premature aging (35)(36)(37), and an increase in SOD1 mRNA and enzymatic activity has been proposed to play an important role in aging (38). Indeed, SOD-1 mRNA levels were shown to be increased in SALS motoneurons in humans (39).…”

mentioning

confidence: 99%

Transgenic mice carrying a human mutant superoxide dismutase transgene develop neuronal cytoskeletal pathology resembling human amyotrophic lateral sclerosis lesions.

Raju

Robinson

et al. 1996

Proc. Natl. Acad. Sci. U.S.A.

367

223

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(16,17). To gain further insights into the pathogenesis of FALS, the studies described in this paper were designed to characterize alterations in the neuronal cytoskeleton in the G1H mice and to compare these alterations with those seen in human ALS.MATERIALS AND METHODS Generation of Human SOD1 Transgenic Mice. The G1H line of transgenic mice carry a human SOD1 gene with a Gly-93 -> Ala substitution (G93A). These derive from a described Gl line (13) and have a 40% expansion in transgene copy number (P. Zhai and M.E.G., unpublished data). The G1H mice have been deposited with the Induced Mutant Resource maintained by The Jackson Laboratory (Bar Harbor, ME) under the strain designation C57BL/6J-TgN(SOD1-G93A)lGur. The N1029

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“…Studies with human and mouse cell lines containing integrated human SOD-1 cDNA revealed that, although the overexpression of SOD-1 makes cells more resistant to O 2 Ϫ challenges, it also enhances lipid peroxidation as a result of the accumulation of hydrogen peroxide (17). In a transgenic mouse line expressing human SOD-1, overexpression of SOD-1 causes clinical symptoms similar to Down's syndrome (6). Reduced levels of SOD-1 are also deleterious, since nearly 20% of amyotrophic lateral sclerosis patients have SOD-1 deficiencies as a result of mutations (15,59).…”

Section: Discussionmentioning

confidence: 99%

Translation of a Testis-Specific Cu/Zn Superoxide Dismutase (SOD-1) mRNA Is Regulated by a 65-Kilodalton Protein Which Binds to Its 5′ Untranslated Region

Hecht

1996

Molecular and Cellular Biology

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Translation of mRNAs is often regulated by specific cytoplasmic proteins that interact with regulatory elements within their 5Ј or 3Ј untranslated regions (UTRs). The iron-responsive-element-binding protein, one of the best-characterized RNA-binding proteins, regulates cellular iron metabolism by binding to sequence elements in the 5Ј UTR of ferritin mRNA and the 3Ј UTR of transferrin receptor mRNA (30,31,34,38,67). Other RNA-binding proteins such as a cytoplasmic polyadenylation element-binding protein mediate mRNA poly(A) elongation during Xenopus oocyte maturation (25, 52), a 70-kDa poly(A)-binding protein binds to poly(A) tails and helps stabilize mRNAs (9, 60), and Xenopus p54 and p56 (47-49) or their mouse homologs p48 and p52 (42, 64) function as masking proteins by binding to stored mRNAs in an apparent sequence-or structure-independent manner.

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Down's syndrome: Abnormal neuromuscular junction in tongue of transgenic mice with elevated levels of human Cu/Zn-superoxide dismutase

Cited by 211 publications

References 19 publications

Superoxide dismutase 1 with mutations linked to familial amyotrophic lateral sclerosis possesses significant activity.

Superoxide dismutase 1 with mutations linked to familial amyotrophic lateral sclerosis possesses significant activity.

Transgenic mice carrying a human mutant superoxide dismutase transgene develop neuronal cytoskeletal pathology resembling human amyotrophic lateral sclerosis lesions.

Translation of a Testis-Specific Cu/Zn Superoxide Dismutase (SOD-1) mRNA Is Regulated by a 65-Kilodalton Protein Which Binds to Its 5′ Untranslated Region

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