Length variation of CAG/CAA triplet repeats in 50 genes among 16 inbred mouse strains.
CAG repeats coding for poly-glutamines have been studied by many groups as repeat length variations contributes to differences in protein function and disease outcome. In this study, we systematically searched public databases for genes carrying CAG repeats. For the genes obtained, we experimentally analyzed variations of length and the purity of the repeats in 62 loci among 16 inbred mouse strains, including wild-derived and laboratory strains. We found that length was conserved in 50% of the loci, especially among wild-derived strains. Of 496 polymorphic repeat alleles, 78% were uninterrupted and 22% were interrupted with non-CAG codons. Interruptions tended to occur in longer repeats and all repeats of greater length than 23 were interrupted. Although interruptions can act as suppressors for the expansion of CAG repeats, we found that the occurrence of the interruptions depended on the length of the CAG repeats. Furthermore, most poly-glutamines examined in this study existed in human orthologous genes, reflecting the functional significance of poly-glutamines in proteins.
Ogasawara
Michihiro
M
Center for Information Biology and DNA Data Bank of Japan, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka-ken 411-8540, Japan.
Imanishi
Tadashi
T
Moriwaki
Kazuo
K
Gaudieri
Silvana
S
Tsuda
Hiroshi
H
Hashimoto
Hiroshi
H
Shiroishi
Toshihiko
T
Gojobori
Takashi
T
Koide
Tsuyoshi
T
D000483:Alleles; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D001483:Base Sequence; D016000:Cluster Analysis; D003062:Codon; D017124:Conserved Sequence; D004247:DNA / Q000235:genetics; D016208:Databases, Factual; D019143:Evolution, Molecular; D014644:Genetic Variation; D051379:Mice; D008815:Mice, Inbred Strains; D008969:Molecular Sequence Data; D010802:Phylogeny; D020641:Polymorphism, Single Nucleotide; D011506:Proteins / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D019680:Trinucleotide Repeat Expansion; D018911:Trinucleotide Repeats
D003062:Codon; D011506:Proteins; D004247:DNA