| 1. |
- Jonasson, Jenni, et al.
(författare)
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Expression of ataxin-7 in CNS and non-CNS tissue of normal and SCA7 individuals
- 2002
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Ingår i: Acta Neuropathologica. - : Springer. - 0001-6322 .- 1432-0533. ; 104:1, s. 29-37
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Tidskriftsartikel (refereegranskat)abstract
- Spinocerebellar ataxia type 7 (SCA7) is a neurodegenerative disorder primarily affecting the cerebellum, brain stem and retina. The disease is caused by an expanded polyglutamine tract in the protein ataxin-7. In this study we analyzed the expression pattern of ataxin-7 in CNS and non-CNS tissue from three SCA7 patients and age-matched controls. SCA7 is a rare autosomal dominant disorder, limiting the number of patients available for analysis. We therefore compiled data on ataxin-7 expression from all SCA7 patients (n=5) and controls (n=7) published to date, and compared with the results obtained in this study. Expression of ataxin-7 was found in neurons throughout the CNS and was highly abundant in Purkinje cells of the cerebellum, in regions of the hippocampus and in cerebral cortex. Ataxin-7 expression was not restricted to regions of pathology, and there were no apparent regional differences in ataxin-7 expression patterns between patients and controls. The subcellular distribution of ataxin-7 was primarily nuclear in all brain regions studied. In cerebellar Purkinje cells, however, differences in subcellular distribution of ataxin-7 were observed between patients and controls of different ages. Here we provide an increased understanding of the distribution of ataxin-7, and the possible implication of subcellular localization of this protein on disease pathology is discussed.
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| 2. |
- Ström, Anna-Lena, et al.
(författare)
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A role for both wild-type and expanded ataxin-7 in transcriptional regulation
- 2005
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Ingår i: Neurobiology of Disease. - : Elsevier BV. - 0969-9961 .- 1095-953X. ; 20:3, s. 646-655
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Tidskriftsartikel (refereegranskat)abstract
- Spinocerebellar ataxia type 7 (SCA7) is a neurodegenerative disease primarily affecting the brainstem, retina and Purkinje cells of the cerebellum. The disease is caused by a polyglutamine expansion in ataxin-7, a protein found in two complexes TFTC and STAGA, involved in transcriptional regulation. Transcriptional dysregulation has been implicated in the pathology of several polyglutamine diseases. In this paper, we analyzed the effect of both wild-type and expanded ataxin-7 on transcription driven by the co-activator CBP and the Purkinje cell expressed nuclear receptor RORα1. We could show that transcription mediated by both CBP and RORα1 was repressed by expanded ataxin-7. Interestingly, repression of transcription could also be observed with wild-type full-length ataxin-7, not only on CBP- and RORα1-mediated transcription, but also on basal transcription. The repression could be counteracted by inhibition of deacetylation, suggesting that ataxin-7 may act as a repressor of transcription by inhibiting the acetylation activity of TFTC and STAGA.
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| 3. |
- Ström, Anna-Lena, et al.
(författare)
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Cloning and expression analysis of the murine homolg of the Spinocerebellar ataxia type 7 (SCA7) gene
- 2002
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Ingår i: Gene. - : Elsevier. ; 285:1-2, s. 91-99
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Tidskriftsartikel (refereegranskat)abstract
- Spinocerebellar ataxia type 7 (SCA7) is a neurodegenerative disease caused by the expansion of a polyglutamine tract in the protein ataxin-7, a protein of unknown function. In order to analyze the expression pattern of wild type ataxin-7 in detail, the murine SCA7 gene homolog was cloned and the expression pattern in mice analyzed. The SCA7 mouse and human gene exhibit a high degree of identity at both DNA (88.2%) and protein (88.7%) level. The CAG repeat region, known to be polymorphic in man, is conserved in mouse but contained only five repeats in all mouse strains analyzed. The arrestin homology domain and the nuclear localization signal found in human ataxin-7 is also conserved in the murine homolog. Expression of ataxin-7 was detected during mouse embryonic development and in all adult mouse tissues examined by northern and western blots. In brain, immunohistological staining revealed an ataxin-7 expression pattern similar to that in human, with ataxin-7 expression in cerebellum, several brainstem nuclei, cerebral cortex and hippocampus. Our data show high conservation of ataxin-7 both structurally and at the level of expression, suggesting a conserved role for the protein in mice and humans.
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| 4. |
- Ström, Anna-Lena, et al.
(författare)
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Identification and characterization of Spinocerebellar Ataxia Type 7 (SCA7) isoform SCA7b in mice
- 2005
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Ingår i: Biochimica et Biophysica Acta. - : Elsevier BV. - 0006-3002 .- 1878-2434. ; 1731:3, s. 149-153
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Tidskriftsartikel (refereegranskat)abstract
- Spinocerebellar ataxia type 7 (SCA7) is a neurodegenerative disease primarily affecting the cerebellum, brainstem and retina. The disease is caused by a polyglutamine expansion in ataxin-7, a protein with largely unknown function. To improve our knowledge of the expression and function of wild-type and expanded ataxin-7, we looked for alternative SCA7 transcripts in mice. We identified a murine SCA7 isoform (SCA7b) containing an uncharacterized exon homologous to the newly identified human exon 12b. Northern blot analysis revealed three exon 12b containing transcripts with molecular sizes of 7.5, 4.4 and 3.0 kb in mice. This contrasted with the situation in humans, where only one exon 12b-containing transcript was observed. Furthermore, Northern blot of the human 4.4 kb SCA7b isoform predominantly showed expression in the brain, while expression of both the murine 7.5-kb and the 4.4-kb transcripts were observed in several tissues including brain, heart, liver, kidney and testis. Quantitative real-time RT-PCR analysis revealed that in muscle and heart SCA7b is the predominant SCA7 isoform, while in brain equal levels of SCA7a and SCA7b was observed. Insertion of exon 12b into the murine SCA7 ORF resulted in a frame-shift that gave rise to an alternative ataxin-7 protein (ataxin-7b). The novel 58-amino acid C-terminus in ataxin-7b directed the protein to a more cytoplasmic location.
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