RNA structure is a key regulatory element in pathological ATM and CFTR pseudoexon inclusion events.
Genomic variations deep in the intronic regions of pre-mRNA molecules are increasingly reported to affect splicing events. However, there is no general explanation why apparently similar variations may have either no effect on splicing or cause significant splicing alterations. In this work we have examined the structural architecture of pseudoexons previously described in ATM and CFTR patients. The ATM case derives from the deletion of a repressor element and is characterized by an aberrant 5'ss selection despite the presence of better alternatives. The CFTR pseudoexon instead derives from the creation of a new 5'ss that is used while a nearby pre-existing donor-like sequence is never selected. Our results indicate that RNA structure is a major splicing regulatory factor in both cases. Furthermore, manipulation of the original RNA structures can lead to pseudoexon inclusion following the exposure of unused 5'ss already present in their wild-type intronic sequences and prevented to be recognized because of their location in RNA stem structures. Our data show that intrinsic structural features of introns must be taken into account to understand the mechanism of pseudoexon activation in genetic diseases. Our observations may help to improve diagnostics prediction programmes and eventual therapeutic targeting.
Buratti
Emanuele
E
International Centre for Genetic Engineering and Biotechnology (ICGEB), 34012 Trieste, Italy.
Dhir
Ashish
A
Lewandowska
Marzena A
MA
Baralle
Francisco E
FE
D001260:Ataxia Telangiectasia / Q000235:genetics; D064007:Ataxia Telangiectasia Mutated Proteins; D001483:Base Sequence; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism; D045744:Cell Line, Tumor; D003550:Cystic Fibrosis / Q000235:genetics; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D007438:Introns; D008969:Molecular Sequence Data; D009154:Mutation; D009690:Nucleic Acid Conformation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism; D012322:RNA Precursors / Q000737:chemistry*; D022821:RNA Splice Sites; D012326:RNA Splicing; D020871:RNA Stability; D012333:RNA, Messenger / Q000737:chemistry*; D038621:Regulatory Sequences, Ribonucleic Acid; D025521:Tumor Suppressor Proteins / Q000235:genetics* / Q000378:metabolism
C505032:CFTR protein, human; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D012322:RNA Precursors; D022821:RNA Splice Sites; D012333:RNA, Messenger; D038621:Regulatory Sequences, Ribonucleic Acid; D025521:Tumor Suppressor Proteins; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D017346:Protein Serine-Threonine Kinases