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Thymidine Kinase 2 and Mitochondrial Protein COX I in the Cerebellum of Patients with Spinocerebellar Ataxia Type 31 Caused by Penta-nucleotide Repeats (TTCCA)(n)

Spinocerebellar ataxia type 31 (SCA31), an autosomal-dominant neurodegenerative disorder characterized by progressive cerebellar ataxia with Purkinje cell degeneration, is caused by a heterozygous 2.5–3.8 kilobase penta-nucleotide repeat of (TTCCA)(n) in intron 11 of the thymidine kinase 2 (TK2) gen...

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Autores principales: Aoki, Hanako, Higashi, Miwa, Okita, Michi, Ando, Noboru, Murayama, Shigeo, Ishikawa, Kinya, Yokota, Takanori
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Springer US 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9883315/
https://www.ncbi.nlm.nih.gov/pubmed/35084690
http://dx.doi.org/10.1007/s12311-021-01364-2
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author Aoki, Hanako
Higashi, Miwa
Okita, Michi
Ando, Noboru
Murayama, Shigeo
Ishikawa, Kinya
Yokota, Takanori
author_facet Aoki, Hanako
Higashi, Miwa
Okita, Michi
Ando, Noboru
Murayama, Shigeo
Ishikawa, Kinya
Yokota, Takanori
author_sort Aoki, Hanako
collection PubMed
description Spinocerebellar ataxia type 31 (SCA31), an autosomal-dominant neurodegenerative disorder characterized by progressive cerebellar ataxia with Purkinje cell degeneration, is caused by a heterozygous 2.5–3.8 kilobase penta-nucleotide repeat of (TTCCA)(n) in intron 11 of the thymidine kinase 2 (TK2) gene. TK2 is an essential mitochondrial pyrimidine-deoxyribonucleoside kinase. Bi-allelic loss-of-function mutations of TK2 lead to mitochondrial DNA depletion syndrome (MDS) in humans through severe (~ 70%) reduction of mitochondrial electron-transport-chain activity, and tk2 knockout mice show Purkinje cell degeneration and ataxia through severe mitochondrial cytochrome-c oxidase subunit I (COX I) protein reduction. To clarify whether TK2 function is altered in SCA31, we investigated TK2 and COX I expression in human postmortem SCA31 cerebellum. We confirmed that canonical TK2 mRNA is transcribed from exons far upstream of the repeat site, and demonstrated that an extended version of TK2 mRNA (“TK2-EXT”), transcribed from exons spanning the repeat site, is expressed in human cerebellum. While canonical TK2 was conserved among vertebrates, TK2-EXT was specific to primates. Reverse transcription-PCR demonstrated that both TK2 mRNAs were preserved in SCA31 cerebella compared with control cerebella. The TK2 proteins, assessed with three different antibodies including our original polyclonal antibody against TK2-EXT, were detected as ~ 26 kilodalton proteins on western blot; their levels were similar in SCA31 and control cerebella. COX I protein level was preserved in SCA31 compared to nuclear DNA-encoded protein. We conclude that the expression and function of TK2 are preserved in SCA31, suggesting a mechanism distinct from that of MDS.
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spelling pubmed-98833152023-01-29 Thymidine Kinase 2 and Mitochondrial Protein COX I in the Cerebellum of Patients with Spinocerebellar Ataxia Type 31 Caused by Penta-nucleotide Repeats (TTCCA)(n) Aoki, Hanako Higashi, Miwa Okita, Michi Ando, Noboru Murayama, Shigeo Ishikawa, Kinya Yokota, Takanori Cerebellum Original Article Spinocerebellar ataxia type 31 (SCA31), an autosomal-dominant neurodegenerative disorder characterized by progressive cerebellar ataxia with Purkinje cell degeneration, is caused by a heterozygous 2.5–3.8 kilobase penta-nucleotide repeat of (TTCCA)(n) in intron 11 of the thymidine kinase 2 (TK2) gene. TK2 is an essential mitochondrial pyrimidine-deoxyribonucleoside kinase. Bi-allelic loss-of-function mutations of TK2 lead to mitochondrial DNA depletion syndrome (MDS) in humans through severe (~ 70%) reduction of mitochondrial electron-transport-chain activity, and tk2 knockout mice show Purkinje cell degeneration and ataxia through severe mitochondrial cytochrome-c oxidase subunit I (COX I) protein reduction. To clarify whether TK2 function is altered in SCA31, we investigated TK2 and COX I expression in human postmortem SCA31 cerebellum. We confirmed that canonical TK2 mRNA is transcribed from exons far upstream of the repeat site, and demonstrated that an extended version of TK2 mRNA (“TK2-EXT”), transcribed from exons spanning the repeat site, is expressed in human cerebellum. While canonical TK2 was conserved among vertebrates, TK2-EXT was specific to primates. Reverse transcription-PCR demonstrated that both TK2 mRNAs were preserved in SCA31 cerebella compared with control cerebella. The TK2 proteins, assessed with three different antibodies including our original polyclonal antibody against TK2-EXT, were detected as ~ 26 kilodalton proteins on western blot; their levels were similar in SCA31 and control cerebella. COX I protein level was preserved in SCA31 compared to nuclear DNA-encoded protein. We conclude that the expression and function of TK2 are preserved in SCA31, suggesting a mechanism distinct from that of MDS. Springer US 2022-01-27 2023 /pmc/articles/PMC9883315/ /pubmed/35084690 http://dx.doi.org/10.1007/s12311-021-01364-2 Text en © The Author(s) 2021 https://creativecommons.org/licenses/by/4.0/Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) .
spellingShingle Original Article
Aoki, Hanako
Higashi, Miwa
Okita, Michi
Ando, Noboru
Murayama, Shigeo
Ishikawa, Kinya
Yokota, Takanori
Thymidine Kinase 2 and Mitochondrial Protein COX I in the Cerebellum of Patients with Spinocerebellar Ataxia Type 31 Caused by Penta-nucleotide Repeats (TTCCA)(n)
title Thymidine Kinase 2 and Mitochondrial Protein COX I in the Cerebellum of Patients with Spinocerebellar Ataxia Type 31 Caused by Penta-nucleotide Repeats (TTCCA)(n)
title_full Thymidine Kinase 2 and Mitochondrial Protein COX I in the Cerebellum of Patients with Spinocerebellar Ataxia Type 31 Caused by Penta-nucleotide Repeats (TTCCA)(n)
title_fullStr Thymidine Kinase 2 and Mitochondrial Protein COX I in the Cerebellum of Patients with Spinocerebellar Ataxia Type 31 Caused by Penta-nucleotide Repeats (TTCCA)(n)
title_full_unstemmed Thymidine Kinase 2 and Mitochondrial Protein COX I in the Cerebellum of Patients with Spinocerebellar Ataxia Type 31 Caused by Penta-nucleotide Repeats (TTCCA)(n)
title_short Thymidine Kinase 2 and Mitochondrial Protein COX I in the Cerebellum of Patients with Spinocerebellar Ataxia Type 31 Caused by Penta-nucleotide Repeats (TTCCA)(n)
title_sort thymidine kinase 2 and mitochondrial protein cox i in the cerebellum of patients with spinocerebellar ataxia type 31 caused by penta-nucleotide repeats (ttcca)(n)
topic Original Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9883315/
https://www.ncbi.nlm.nih.gov/pubmed/35084690
http://dx.doi.org/10.1007/s12311-021-01364-2
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