| Budget Amount *help |
¥43,600,000 (Direct Cost: ¥43,600,000)
Fiscal Year 2009: ¥8,000,000 (Direct Cost: ¥8,000,000)
Fiscal Year 2008: ¥8,000,000 (Direct Cost: ¥8,000,000)
Fiscal Year 2007: ¥8,800,000 (Direct Cost: ¥8,800,000)
Fiscal Year 2006: ¥8,800,000 (Direct Cost: ¥8,800,000)
Fiscal Year 2005: ¥10,000,000 (Direct Cost: ¥10,000,000)
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| Research Abstract |
Human spinocerebellar ataxia type 10 is caused by ATTCT expansion in the ATXN10 gene. We found LINE-1 was inserted into ATXN10 intron; Alu was then inserted in the LINE-1; and endogenous retrovilcus K was lastly retrotransposed in the Alu. The ATTCT repeat was located on the 3'-end of the Alu. Using 33 primate species, we revealed that nucleotide substitutions in a poly(A) tail of the Alu element and the following amplification of pentanucleotides occurred in the lineages of catarrhines and that ATTCT repeats originated in the common ancestor of hominoids. Hoxd-13 has taxon-specific polyalanine tracts in amniotes. We replaced the wild-type Hoxd-13 gene with one lacking the 15-residue polyalanine tract. Sesamoid bone formation in knock-in mice was different from that in the wild type. The present study provides the first direct evidence that taxon-specific homopolymeric amino acid repeats are involved in phenotypic diversification at the organismal level. Homopolymeric amino acid repeats are tandem repeats of single amino acids, and are considered to be structurally/intrinsically disordered. We found a number of the repeats predicted to have nondisordered structure and substitution rates showed a higher Ka/Ks ratio for the genes with not disordered repeats than the genes with disordered repeats, showing elevated amino acid substitution rates in genes with nondisordered repeats.
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