BACKGROUND: Spinocerebellar ataxia type 10 (SCA10) is an autosomal dominant disorder characterized by cerebellar ataxia and seizures. SCA10 is caused by an expansion of an ATTCT pentanucleotide repeat in intron 9 of the ataxin 10 (ATXN10) gene encoding an approximately 55-kd protein of unknown function. However, how this mutation leads to SCA10 is unknown. METHODS: In an effort to understand the pathogenic mechanism of SCA10, the authors conducted a series of experiments to address the effect of repeat expansion on the transcription and RNA processing of the ATXN10 gene. In addition, we generated Sca10 (mouse ataxin 10 homolog)-null mice and addressed the role of Sca10 gene dosage on the cerebellum. RESULTS: Mutant ATXN10 allele is transcribed at the normal level, and the pre-mRNA containing an expanded repeat is processed normally in patient-derived cells. Sca10-null mice exhibited embryonic lethality. Heterozygous mutants were overtly normal and did not develop SCA10 phenotype CONCLUSION: A simple gain of function or loss of function of ATXN10 is unlikely to be the major pathogenic mechanism contributing to the spinocerebellar ataxia type 10 phenotype.
BACKGROUND:Spinocerebellar ataxia type 10 (SCA10) is an autosomal dominant disorder characterized by cerebellar ataxia and seizures. SCA10 is caused by an expansion of an ATTCT pentanucleotide repeat in intron 9 of the ataxin 10 (ATXN10) gene encoding an approximately 55-kd protein of unknown function. However, how this mutation leads to SCA10 is unknown. METHODS: In an effort to understand the pathogenic mechanism of SCA10, the authors conducted a series of experiments to address the effect of repeat expansion on the transcription and RNA processing of the ATXN10 gene. In addition, we generated Sca10 (mouseataxin 10 homolog)-null mice and addressed the role of Sca10 gene dosage on the cerebellum. RESULTS: Mutant ATXN10 allele is transcribed at the normal level, and the pre-mRNA containing an expanded repeat is processed normally in patient-derived cells. Sca10-null mice exhibited embryonic lethality. Heterozygous mutants were overtly normal and did not develop SCA10 phenotype CONCLUSION: A simple gain of function or loss of function of ATXN10 is unlikely to be the major pathogenic mechanism contributing to the spinocerebellar ataxia type 10 phenotype.
Authors: Misti C White; Rui Gao; Weidong Xu; Santi M Mandal; Jung G Lim; Tapas K Hazra; Maki Wakamiya; Sharon F Edwards; Salmo Raskin; Hélio A G Teive; Huda Y Zoghbi; Partha S Sarkar; Tetsuo Ashizawa Journal: PLoS Genet Date: 2010-06-10 Impact factor: 5.917