Splicing regulation in spinal muscular atrophy by an RNA structure formed by long-distance interactions.
Humans carry two copies of the survival motor neuron gene: SMN1 and SMN2. Loss of SMN1 coupled with skipping of SMN2 exon 7 causes spinal muscular atrophy (SMA), a leading genetic disease associated with infant mortality. Our discovery of intronic splicing silencer N1 (ISS-N1) is a promising target, currently in a phase III clinical trial, for an antisense oligonucleotide-mediated splicing correction in SMA. We have recently shown that the first residue of ISS-N1 is locked in a unique RNA structure that we term ISTL1 (internal stem through long-distance interaction-1). Complementary strands of ISTL1 are separated from each other by 279 nucleotides. Using site-specific mutations and chemical structure probing, we confirmed the formation and functional significance of ISTL1. Located in the middle of intron 7, the 3' strand of ISTL1 falls within an inhibitory region that we term ISS-N2. We demonstrate that an antisense oligonucleotide-mediated sequestration of ISS-N2 fully corrects SMN2 exon 7 splicing and restores high levels of SMN in SMA patient cells. These results underscore the therapeutic potential of the regulatory information present in a secondary and high-order RNA structure of a human intron.
Department of Biomedical Sciences, Iowa State University, Ames, Iowa.
Natalia N
NN
Singh
Brian M
BM
Lee
Ravindra N
RN
Singh
D001483:Base Sequence; D005091:Exons / Q000235:genetics; D000076245:Heterogeneous Nuclear Ribonucleoprotein A1; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007438:Introns / Q000235:genetics*; D008957:Models, Genetic; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009134:Muscular Atrophy, Spinal / Q000235:genetics* / Q000473:pathology / Q000628:therapy; D009154:Mutation; D009690:Nucleic Acid Conformation; D016376:Oligonucleotides, Antisense / Q000235:genetics*; D012313:RNA / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D012326:RNA Splicing; D055533:Survival of Motor Neuron 1 Protein / Q000235:genetics; D055540:Survival of Motor Neuron 2 Protein / Q000235:genetics
D000076245:Heterogeneous Nuclear Ribonucleoprotein A1; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B; D016376:Oligonucleotides, Antisense; C526471:SMN1 protein, human; C526477:SMN2 protein, human; D055533:Survival of Motor Neuron 1 Protein; D055540:Survival of Motor Neuron 2 Protein; D012313:RNA
RNA structure; alternative splicing; antisense oligonucleotide; spinal muscular atrophy; survival motor neuron