SRp30c-dependent stimulation of survival motor neuron (SMN) exon 7 inclusion is facilitated by a direct interaction with hTra2 beta 1.
Proximal spinal muscular atrophy (SMA) is caused by the homozygous loss of survival motor neuron (SMN1). SMN2, a nearly identical copy gene, is present in all SMA patients; however this gene cannot provide protection from disease due to the aberrant splicing of a critical exon. SMN1-derived transcripts are exclusively full-length, whereas SMN2-derived transcripts predominantly lack SMN exon 7. A single non-polymorphic nucleotide difference (C in SMN1; T in SMN2) is responsible for the alternative splicing patterns. We have previously shown that transient expression of an SR-like splicing factor, hTra2 beta 1, stimulates inclusion of exon 7 in SMN2-derived mini-gene transcripts through an interaction with the AG-rich exonic splice enhancer within exon 7. We now demonstrate that a second splicing factor, SRp30c, can stimulate SMN exon 7-inclusion and that this activity required the same AG-rich enhancer as hTra2 beta 1. SRp30c did not directly associate with SMN exon 7; rather its association with the exonic enhancer was mediated by a direct interaction with hTra2 beta 1. In the absence of the hTra2 beta 1 binding site, SRp30c failed to complex with SMN exon 7. Taken together, these results identify SRp30c as a modulator of SMN exon 7-inclusion and provide insight into the molecular regulation of this critical exon.
Young
Philip J
PJ
Arizona State University, Department of Biology, Tempe, AZ 85287-1501, USA.
DiDonato
Christine J
CJ
Hu
Diane
D
Kothary
Rashmi
R
Androphy
Elliot J
EJ
Lorson
Christian L
CL
D017398:Alternative Splicing; D001483:Base Sequence; D001665:Binding Sites; D017362:Cyclic AMP Response Element-Binding Protein; D004742:Enhancer Elements, Genetic / Q000235:genetics; D005091:Exons; D006367:HeLa Cells; D006801:Humans; D009046:Motor Neurons / Q000378:metabolism*; D009134:Muscular Atrophy, Spinal / Q000235:genetics* / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics*; D009687:Nuclear Proteins / Q000235:genetics*; D010750:Phosphoproteins / Q000235:genetics*; D020033:Protein Isoforms / Q000235:genetics; D012313:RNA / Q000378:metabolism; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins / Q000302:isolation & purification; D055532:SMN Complex Proteins; D000068103:Serine-Arginine Splicing Factors; D055533:Survival of Motor Neuron 1 Protein; D055540:Survival of Motor Neuron 2 Protein; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured
D017362:Cyclic AMP Response Element-Binding Protein; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D010750:Phosphoproteins; D020033:Protein Isoforms; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins; D055532:SMN Complex Proteins; C526471:SMN1 protein, human; C526477:SMN2 protein, human; D055533:Survival of Motor Neuron 1 Protein; D055540:Survival of Motor Neuron 2 Protein; C097083:TRA2B protein, human; D000068103:Serine-Arginine Splicing Factors; D012313:RNA