Nuclear factor TDP-43 and SR proteins promote in vitro and in vivo CFTR exon 9 skipping.
Alternative splicing of human cystic fibrosis transmembrane conductance regulator (CFTR) exon 9 is regulated by a combination of cis-acting elements distributed through the exon and both flanking introns (IVS8 and IVS9). Several studies have identified in the IVS8 intron 3' splice site a regulatory element that is composed of a polymorphic (TG)m(T)n repeated sequence. At present, no cellular factors have been identified that recognize this element. We have identified TDP-43, a nuclear protein not previously described to bind RNA, as the factor binding specifically to the (TG)m sequence. Transient TDP-43 overexpression in Hep3B cells results in an increase in exon 9 skipping. This effect is more pronounced with concomitant overexpression of SR proteins. Antisense inhibition of endogenous TDP-43 expression results in increased inclusion of exon 9, providing a new therapeutic target to correct aberrant splicing of exon 9 in CF patients. The clinical and biological relevance of this finding in vivo is demonstrated by our characterization of a CF patient carrying a TG10T9(DeltaF508)/TG13T3(wt) genotype leading to a disease-causing high proportion of exon 9 skipping.
Buratti
E
E
International Centre for Genetic Engineering and Biotechnology (ICGEB), Padriciano 99, 34012 Trieste, Italy.
Dörk
T
T
Zuccato
E
E
Pagani
F
F
Romano
M
M
Baralle
F E
FE
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005091:Exons; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011110:Polymorphism, Genetic; D016372:RNA, Antisense; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012091:Repetitive Sequences, Nucleic Acid; D000068103:Serine-Arginine Splicing Factors; D014018:Tissue Distribution; D014162:Transfection
C505032:CFTR protein, human; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D016372:RNA, Antisense; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D000068103:Serine-Arginine Splicing Factors; D005982:Glutathione Transferase