Allele-specific silencing of mutant huntingtin and ataxin-3 genes by targeting expanded CAG repeats in mRNAs.
Expanded trinucleotide repeats cause many neurological diseases. These include Machado-Joseph disease (MJD) and Huntington's disease (HD), which are caused by expanded CAG repeats within an allele of the ataxin-3 (ATXN3) and huntingtin (HTT) genes, respectively. Silencing expression of these genes is a promising therapeutic strategy, but indiscriminate inhibition of both the mutant and wild-type alleles may lead to toxicity, and allele-specific approaches have required polymorphisms that differ among individuals. We report that peptide nucleic acid and locked nucleic acid antisense oligomers that target CAG repeats can preferentially inhibit mutant ataxin-3 and HTT protein expression in cultured cells. Duplex RNAs were less selective than single-stranded oligomers. The activity of the peptide nucleic acids does not involve inhibition of transcription, and differences in mRNA secondary structure or the number of oligomer binding sites may be important. Antisense oligomers that discriminate between wild-type and mutant genes on the basis of repeat length may offer new options for developing treatments for MJD, HD and related hereditary diseases.
Hu
Jiaxin
J
Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, USA.
Matsui
Masayuki
M
Gagnon
Keith T
KT
Schwartz
Jacob C
JC
Gabillet
Sylvie
S
Arar
Khalil
K
Wu
Jun
J
Bezprozvanny
Ilya
I
Corey
David R
DR
D000818:Animals; D000067699:Ataxin-3; D002460:Cell Line; D002478:Cells, Cultured; D005260:Female; D005347:Fibroblasts / Q000378:metabolism; D006801:Humans; D000071058:Huntingtin Protein; D006816:Huntington Disease / Q000235:genetics*; D017827:Machado-Joseph Disease / Q000235:genetics; D008297:Male; D051379:Mice; D009419:Nerve Tissue Proteins / Q000235:genetics*; D009687:Nuclear Proteins / Q000235:genetics*; D016376:Oligonucleotides, Antisense / Q000378:metabolism*; D020135:Peptide Nucleic Acids / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics*; D019680:Trinucleotide Repeat Expansion
C086055:HTT protein, human; D000071058:Huntingtin Protein; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D016376:Oligonucleotides, Antisense; D020135:Peptide Nucleic Acids; D012097:Repressor Proteins; C092341:ATXN3 protein, human; D000067699:Ataxin-3