A nonpathogenic GAAGGA repeat in the Friedreich gene: implications for pathogenesis.
An individual with late-onset ataxia was found to be heterozygous for an unusual (GAAGGA)65 sequence and a normal GAA repeat in the frataxin gene. No frataxin point mutation was present, excluding a form of Friedreich ataxia. (GAAGGA)65 did not have the inhibitory effect on gene expression in transfected cells shown by pathogenic GAA repeats of similar length. GAA repeats, but not (GAAGGA)65, adopt a triple helical conformation in vitro. We suggest that such a triplex structure is essential for suppression of gene expression.
Ohshima
K
K
Centre Hospitalier de l'Université de Montréal, Hôpital Notre-Dame, Quebec, Canada.
Sakamoto
N
N
Labuda
M
M
Poirier
J
J
Moseley
M L
ML
Montermini
L
L
Ranum
L P
LP
Wells
R D
RD
Pandolfo
M
M
D000368:Aged; D000483:Alleles; D001483:Base Sequence / Q000235:genetics; D005621:Friedreich Ataxia / Q000235:genetics*; D006801:Humans; D033862:Iron-Binding Proteins; D008297:Male; D008969:Molecular Sequence Data; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics*; D017433:Protein Structure, Secondary; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics*; D000096923:Frataxin
D033862:Iron-Binding Proteins; D017853:Phosphotransferases (Alcohol Group Acceptor); D000096923:Frataxin