-
F Maltecca,
A Filla,
I Castaldo,
G Coppola,
N A Fragassi,
M Carella,
A Bruni,
S Cocozza,
G Casari, A Servadio,
G De Michele
[show abstract]
[hide abstract]
ABSTRACT: The authors describe an Italian family with autosomal dominant ataxia, dementia, psychiatric and extrapyramidal features, epilepsy, mild sensorimotor axonal neuropathy, and MRI findings of cerebral and cerebellar atrophy. A child had a distinctive presentation with onset at 3 years, growth retardation, fast progression, and early death. Molecular analysis demonstrated an expanded CAG/CAA repeat in the TBP gene (SCA-17). The repeat size was 66 triplets in the child and 53 in all the other patients.
Neurology 12/2003; 61(10):1441-3. · 8.31 Impact Factor
-
G De Michele,
F Maltecca,
M Carella,
G Volpe,
M Orio,
A De Falco,
S Gombia, A Servadio,
G Casari,
A Filla,
A Bruni
[show abstract]
[hide abstract]
ABSTRACT: We observed two families with a dominantly inherited complex neurological syndrome with onset in adulthood. Family F included 9 affected in four generations. One patient showed prominent anticipation of onset age. Onset was with cerebellar signs followed by dementia, psychiatric symptoms, seizures, and extrapyramidal features. Family M included 14 affected individuals in five generations. Presenting symptoms were either psychiatric and cognitive impairment or a cerebellar syndrome. Extrapyramidal features, dysphagia, incontinence, seizures, and myoclonus may occur. In both families magnetic resonance imaging showed marked atrophy of the brain and cerebellum. Molecular analyses demonstrated an expanded CAG/CAA repeat in the in the TATA box-binding protein (TBP) gene (SCA17).
Neurological Sciences 11/2003; 24(3):166-7. · 1.32 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Spinocerebellar ataxia type 1 (SCA1) is one of several neurodegenerative disorders caused by an expansion of a polyglutamine tract. It is characterized by ataxia, progressive motor deterioration, and loss of cerebellar Purkinje cells. To understand the pathogenesis of SCA1, we examined the subcellular localization of wild-type human ataxin-1 (the protein encoded by the SCA1 gene) and mutant ataxin-1 in the Purkinje cells of transgenic mice. We found that ataxin-1 localizes to the nuclei of cerebellar Purkinje cells. Normal ataxin-1 localizes to several nuclear structures approximately 0.5 microm across, whereas the expanded ataxin-1 localizes to a single approximately 2-microm structure, before the onset of ataxia. Mutant ataxin-1 localizes to a single nuclear structure in affected neurons of SCA1 patients. Similarly, COS-1 cells transfected with wild-type or mutant ataxin-1 show a similar pattern of nuclear localization; with expanded ataxin-1 occurring in larger structures that are fewer in number than those of normal ataxin-1. Colocalization studies show that mutant ataxin-1 causes a specific redistribution of the nuclear matrix-associated domain containing promyelocytic leukaemia protein. Nuclear matrix preparations demonstrate that ataxin-1 associates with the nuclear matrix in Purkinje and COS cells. We therefore propose that a critical aspect of SCA1 pathogenesis involves the disruption of a nuclear matrix-associated domain.
Nature 11/1997; 389(6654):971-4. · 36.28 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Spinocerebellar ataxia type 1 (SCA1) is an autosomal dominant neurodegenerative disorder caused by the expansion of a CAG trinucleotide repeat which encodes glutamine in the novel protein ataxin-1. In order to characterize the developmental expression pattern of SCA1 and to identify putative functional domains in ataxin-1, the murine homolog (Sca1) was isolated. Cloning and characterization of the murine Sca1 gene revealed that the gene organization is similar to that of the human gene. The murine and human ataxin-1 are highly homologous but the CAG repeat is virtually absent in the mouse sequence suggesting that the polyglutamine stretch is not essential for the normal function of ataxin-1 in mice. Cellular and developmental expression of the murine homolog was examined using RNA in situ hybridization. During cerebellar development, there is a transient burst of Sca1 expression at postnatal day 14 when the murine cerebellar cortex becomes physiologically functional. There is also marked expression of Sca1 in mesenchymal cells of the intervertebral discs during development of the spinal column. These results suggest that the normal Sca1 gene, has a role at specific stages of both cerebellar and vertebral column development.
Human Molecular Genetics 02/1996; 5(1):33-40. · 7.64 Impact Factor
-
Genomics 11/1995; 29(3):812-3. · 3.02 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Spinocerebellar ataxia type 1 (SCA1) is an autosomal dominant inherited disorder characterized by degeneration of cerebellar Purkinje cells, spinocerebellar tracts, and selective brainstem neurons owing to the expansion of an unstable CAG trinucleotide repeat. To gain insight into the pathogenesis of the SCA1 mutation and the intergenerational stability of trinucleotide repeats in mice, we have generated transgenic mice expressing the human SCA1 gene with either a normal or an expanded CAG tract. Both transgenes were stable in parent to offspring transmissions. While all six transgenic lines expressing the unexpanded human SCA1 allele had normal Purkinje cells, transgenic animals from five of six lines with the expanded SCA1 allele developed ataxia and Purkinje cell degeneration. These data indicate that expanded CAG repeats expressed in Purkinje cells are sufficient to produce degeneration and ataxia and demonstrate that a mouse model can be established for neurodegeneration caused by CAG repeat expansions.
Cell 10/1995; 82(6):937-48. · 32.40 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Spinocerebellar ataxia type 1 (SCA1) is an autosomal dominant neurodegenerative disorder caused by expansion of a CAG trinucleotide repeat which codes for glutamine in the protein ataxin-1. We have investigated the effect of this expansion on ataxin-1 by immunoblot analysis. The wild-type protein is detected in both normal and affected individuals; however, a mutant protein which varies in its migration properties according to the size of the CAG repeat is detected in cultured cells and tissues from SCA1 individuals. The protein has a nuclear localization in all normal and SCA1 brain regions examined but a cytoplasmic localization of ataxin-1 was also observed in cerebellar Purkinje cells. Our data show that in SCA1, the expanded alleles are faithfully translated into proteins of apparently normal stability and distribution.
Nature Genetics 06/1995; 10(1):94-8. · 35.53 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Spinocerebellar ataxia type 1 (SCA1) is a neurodegenerative disorder caused by expansion of a CAG trinucleotide repeat. In this study, we describe the identification and characterization of the gene harbouring this repeat. The SCA1 transcript is 10,660 bases and is transcribed from both the wild type and SCA1 alleles. The CAG repeat, coding for a polyglutamine tract, lies within the coding region. The gene spans 450 kb of genomic DNA and is organized in nine exons. The first seven fall in the 5' untranslated region and the last two contain the coding region, and a 7,277 basepairs 3' untranslated region. The first four non-coding exons undergo alternative splicing in several tissues. These features suggest that the transcriptional and translational regulation of ataxin-1, the SCA1 encoded protein, may be complex.
Nature Genetics 09/1994; 7(4):513-20. · 35.53 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Spinocerebellar ataxia type 1 (SCA1) is an autosomal dominant disorder characterized by neurodegeneration of the cerebellum and brainstem. The mutation in SCA1 involves the expansion of a highly polymorphic CAG trinucleotide repeat located within the coding region of a novel gene on the short arm of human chromosome 6. The SCA1 transcript is 10,660 bases and has a wide pattern of expression. The gene product, ataxin-1, is predicted to contain 792-825 amino acids (depending on the size of the CAG repeat on normal alleles) and does not share any homology with any known protein. The structure of this gene is unusual in that it contains seven exons in the 5{prime} untranslated region (5{prime} UTR) and two large exons (2080 and 7805 bp respectively) which contain the coding region, and a 7277 bp 3{prime} untranslated region (3{prime} UTR). In order to identify putative functional domains of ataxin-1 and to investigate the significance of the long 5{prime} UTR, we began characterizing the murine homolog of the SCA1 gene (Sca1). Northern analysis revealed that the size of the Sca1 transcript is approximately 10.5 kb. Sequence analysis of more than 3 kb of the murine gene revealed that Sca1 encodes for a predicted protein of 792 amino acids which shows 89% peptide identity with the human protein. The murine Sca1 gene contains only two CAG repeats suggesting that the polyglutamine tract is not essential for the normal function of this protein. Preliminary analysis of the murine locus suggests that it is very similar to the human locus with two large exons containing the coding region and a very long 3{prime} UTR. Sequence homology between the mouse and human homologs extends into the 5{prime} UTR and 3{prime} UTR with 85% and 63% identity respectively. Detailed characterization of the 5{prime} UTR in the mouse is currently in progress to determine its potential role in the regulation of transcription and/or translation of this gene.
The American Journal of Human Genetics 08/1994; 55(Suppl.3). · 10.60 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Spinocerebellar ataxia type I (SCAI) is an autosomal dominant neurodegenerative disease caused by the expansion of a CAG trinucleotide repeat on chromosome 6p. Normal alleles range from 19-36 repeats while SCA1 alleles contain 43-81 repeats. We now show that in 63% of paternal transmissions, an increase in repeat number is observed, whereas 69% of maternal transmissions showed no change or a decrease in repeat number. Sequence analysis of the repeat from 126 chromosomes reveals an interrupted repeat configuration in 98% of the unexpanded alleles but a contiguous repeat (CAG)n configuration in 30 expanded alleles from seven SCA1 families. This indicates that the repeat instability in SCA1 is more complex than a simple variation in repeat number and that the loss of an interruption predisposes the SCA1 (CAG)n to expansion.
Nature Genetics 12/1993; 5(3):254-8. · 35.53 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Spinocerebellar ataxia type 1 (SCA1) is an autosomal dominant disorder characterized by neurodegeneration of the cerebellum, spinal cord and brainstem. A 1.2-Megabase stretch of DNA from the short arm of chromosome 6 containing the SCA1 locus was isolated in a yeast artificial chromosome contig and subcloned into cosmids. A highly polymorphic CAG repeat was identified in this region and was found to be unstable and expanded in individuals with SCA1. There is a direct correlation between the size of the (CAG)n repeat expansion and the age-of-onset of SCA1, with larger alleles occurring in juvenile cases. We also show that the repeat is present in a 10 kilobase mRNA transcript. SCA1 is therefore the fifth genetic disorder to display a mutational mechanism involving an unstable trinucleotide repeat.
Nature Genetics 08/1993; 4(3):221-6. · 35.53 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Rat calpastatin cDNAs obtained by RT-PCR method were isolated and directly sequenced; this allowed the identification of two new variants both characterized by a 23 amino acids deletion at the end of the unique N-terminal domain L, increasing the number of functional isoforms. The deletion shows high homology to the amino acid sequence coded by exon 8 of human calpastatin gene and properly conserved splicing consensus sequences, suggesting exon skipping in domain L. Furthermore, three point mutations scattered along the coding region were found.
Biochemistry and molecular biology international 08/1993; 30(4):721-5.
-
[show abstract]
[hide abstract]
ABSTRACT: The levels of preproneuropeptide Y (ppNPY) mRNA and preprosomatostatin (ppSOM) mRNA were analyzed in different brain regions during the development of hippocampal kindling in rats. ppNPY mRNA levels were markedly elevated in the dorsal hippocampus bilaterally, two days after stage 2 (preconvulsive stage) and stage 5 (full seizure expression). The contents of ppSOM mRNA were slightly, although not significantly, increased in the dorsal hippocampus at stage 2 whereas a significant increase was observed in the ipsilateral hippocampus of fully kindled rats. ppNPY and ppSOM mRNA levels were unchanged in the cortex and striatum at both stages of kindling. These results show that an increased synthesis of somatostatin and neuropeptide Y, with a greater effect for the latter, occurs during hippocampal kindling in rats. The relative role of the two peptides in the development and expression of kindling phenomenon remains to be elucidated.
Neuroscience Letters 12/1991; 132(2):175-8. · 2.11 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Using in situ hybridization, we examined the distribution of the mRNA encoding for the growth-associated protein GAP-43 in the brain stem of adult rats. GAP-43 was expressed at the highest level in the nucleus raphe dorsalis (NDR), nucleus centralis superior (NCS), substantia nigra compacta (SNc), ventral tegmental area (VTA), and locus coeruleus (LC). An intermediate level of signal was detected over the periaque-ductal gray, superior colliculi, and thalamic region, and no significant signal was detected in the substantia nigra pars reticulata and red nucleus. The hybridization signals of GAP-43 mRNA and tryptophan hydroxylase mRNA completely overlapped in the NDR and NCS, and signals for GAP-43 mRNA and tyrosine hydroxylase mRNA overlapped in the SNc, VTA, and LC. The disappearance of the hybridization signal for GAP-43 mRNA after intracerebroventricular injections of the neurotoxins 5,7-dihydroxytryptamine (5,7-DHT) or 6-hydroxydopamine (6-OHDA) indicated that high levels of GAP-43 are synthesized in the serotonergic neurons of the raphe nuclei and in the catecholaminergic neurons of the SNc, VTA, and LC. In light of the role of GAP-43 in axonal outgrowth, modulation of signal transduction, and release of different neurotransmitters in the adult CNS, this phosphoprotein might be involved in the functional plasticity and synaptic transmission of monoaminergic neurons.
Journal of Neuroscience 04/1991; 11(3):600-7. · 7.11 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Neurons expressing the tryptophan hydroxylase (TPH) mRNA within the raphe nuclei of control rats showed a distribution similar to that observed using an antibody for TPH. Numerous packed cells expressing the TPH mRNA were observed in the ventral and dorsal zone of the nucleus raphe dorsalis (NDR) and in the pars dorsalis of the nucleus centralis superior (NCS) whereas fewer and more scattered neurons were found in the pars medialis of NCS. Five days after the intracerebroventricular injection of 5,7-dihydroxytryptamine (5,7-DHT), which markedly reduced the serotonin (5-HT) content in the hippocampus, caudate putamen and cortex, the hybridization signal had completely disappeared in the dorsal region of the NDR. In the ventromedial region, above and between the medial longitudinal fasciculus (MLF), which includes the pars dorsalis of NCS, there was a partial decrease of cell number and a marked increase of the grain density over spared neurons. No significant change was noted in the number of TPH-positive cells and hybridization signal in individual neurons of the pars medialis of NCS. Consistent with previous evidence of increased TPH activity in the residual 5-HT terminals, the present study shows that synthesis of the TPH mRNA may be augmented in some neurons surviving the lesion.
Molecular Brain Research 11/1990; 8(4):343-8. · 2.00 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Individually over-expressed chaperones can interfere with cytotoxicity and aggregation of polyglutamine proteins in disease models. As chaperones cooperate, the analysis of suppression or reversal of polyglutamine pathology may require ways to up-regulate multiple chaperone coding genes. This condition might be achieved by exogenous expression of de-repressed forms of heat shock transcription factor 1 (HSF1), which mediates induction of several genes coding cytosolic and nuclear chaperones. Here we present the rationale behind this possible approach and the caveats, and employ a non-neuronal cell system to test whether Ataxin-1 aggregation can be modulated by de-repressed HSF1 mutants through augmented expression of chaperone coding genes. In our experiments, HSF1 mutants have induced heat shock protein 70 and Human DnaJ (HDJ)-1 to intermediate levels. Cells expressing such mutants also showed partial reduction of Ataxin-1 [31Q] aggregation. A consolidated positive outcome of these tests in cellular models would encourage experiments in transgenic mice and prospects for pharmacological modulation of HSF1 activity or delivery.
Brain Research Bulletin 56(3-4):353-62. · 2.82 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Spinocerebellar ataxia type 1 is a neurodegenerative disease caused by expansion of an uninterrupted glutamine repeat in ataxin-1 protein. Protein aggregation and immunoreactivity to 1C2 monoclonal antibody are two distinct pathognomonic features of expanded ataxin-1, as well as of other polyglutamine disorders. Rare cases of non-affected elderly subjects carrying expanded ataxin-1 alleles were found in random population. However, in these alleles the glutamine stretch was interrupted by histidines. Due to lack of phenotype, these alleles should be considered "normal". Most importantly, occurrence of these unusual alleles provides a unique opportunity to investigate which molecular properties of expanded ataxin-1 are not coupled to polyglutamine pathogenesis. Towards this goal, we compared in vitro the immunoreactivity to 1C2 antibody and the ability to form aggregates of interrupted and uninterrupted alleles. Immunoblotting showed that expanded-interrupted ataxin-1 had an affinity to 1C2 resembling that of normal ataxin-1. On the contrary, filter assay showed that aggregation rate of expanded-interrupted ataxin-1 resembles that of expanded-uninterrupted ataxin-1. These observations indicate that affinity for 1C2 does not directly correlate with self-aggregation of ataxin-1. Moreover, self-aggregation is not directly affected by histidine interruptions. In conclusion, these results support the hypothesis that mechanisms underlying neuronal degeneration are triggered by protein misfolding rather than by protein aggregation.
Brain Research Bulletin 56(3-4):337-42. · 2.82 Impact Factor
-
