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Shibata, H, Huynh, DP and Pulst, SM (2000) A novel protein with RNA-binding motifs interacts with ataxin-2. Hum. Mol. Genet. 9:1303-13

Spinocerebellar ataxia type 2 (SCA2) is caused by expansion of a polyglutamine tract in ataxin-2, a protein of unknown function. Using the yeast two-hybrid system, we identified a novel protein, A2BP1 (ataxin-2 binding protein 1) which binds to the C-terminus of ataxin-2. Northern blot analysis showed that A2BP1 was predominantly expressed in muscle and brain. By immunocfluorescent staining, A2BP1 and ataxin-2 were both localized to the trans -Golgi network. Immunocytochemistry showed that A2BP1 was expressed in the cytoplasm of Purkinje cells and dentate neurons in a pattern similar to that seen for ataxin-2 labeling. Western blot analysis of subcellular fractions indicated enrichment of A2BP1 in the same fractions as ataxin-2. Sequence analysis of the A2BP1 cDNA revealed an RNP motif that is highly conserved among RNA-binding proteins. A2BP1 had striking homology with a human cDNA clone, P83A20, of unknown function and at least two copies of A2BP1 homologs are found in the Caenorhabditis elegans genome database. A2BP1 and related proteins appear to form a novel gene family sharing RNA-binding motifs.

PubMed

Adult; Amino Acid Motifs; Amino Acid Sequence; Blotting, Northern; Blotting, Western; Brain/metabolism; Caenorhabditis elegans Proteins; DNA, Complementary/metabolism; Fluorescent Antibody Technique; Humans; Molecular Sequence Data; Muscles/metabolism; Nerve Tissue Proteins; Neurons/metabolism; Precipitin Tests; Protein Binding; Proteins/chemistry; Proteins/metabolism; Purkinje Cells/metabolism; RNA-Binding Proteins/biosynthesis; RNA-Binding Proteins/genetics; RNA-Binding Proteins/metabolism; Sequence Homology, Amino Acid; Spinocerebellar Ataxias/metabolism; Tissue Distribution; Two-Hybrid System Techniques