U7 snRNA-mediated correction of aberrant splicing caused by activation of cryptic splice sites.
A considerable fraction of mutations associated with hereditary disorders and cancers affect splicing. Some of them cause exon skipping or the inclusion of an additional exon, whereas others lead to the inclusion of intronic sequences or deletion of exonic sequences through the activation of cryptic splice sites. We focused on the latter cases and have designed a series of vectors that express modified U7 small nuclear RNAs (snRNAs) containing a sequence antisense to the cryptic splice site. Three cases of such mutation were investigated in this study. In two of them, which occurred in the PTCH1 and BRCA1 genes, canonical splice donor sites had been partially impaired by mutations that activated nearby intronic cryptic splice donor sites. Another mutation found in exonic region in CYP11A created a novel splice donor site. Transient expression of the engineered U7 snRNAs in HeLa cells restored correct splicing in a sequence-specific and dose-dependent manner in the former two cases. In contrast, the third case, in which the cryptic splice donor site in the exonic sequence was activated, the expression of modified U7 snRNA resulted in exon skipping. The correction of aberrant splicing by suppressing intronic cryptic splice sites with modified U7 is expected be a promising alternative to gene replacement therapy.
Uchikawa
Hideki
H
Department of Genetics, National Research Institute for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo, 157-8535, Japan.|Department of Pediatrics, Graduate School of Medicine, Chiba University, Chiba, 260-8670, Japan.
Fujii
Katsunori
K
Department of Pediatrics, Graduate School of Medicine, Chiba University, Chiba, 260-8670, Japan.
Kohno
Yoichi
Y
Department of Pediatrics, Graduate School of Medicine, Chiba University, Chiba, 260-8670, Japan.
Katsumata
Noriyuki
N
Department of Endocrinology and Metabolism, National Research Institute for Child Health and Development, Tokyo, 157-8535, Japan.
Nagao
Kazuaki
K
Department of Genetics, National Research Institute for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo, 157-8535, Japan.
Yamada
Masao
M
Department of Genetics, National Research Institute for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo, 157-8535, Japan.
Miyashita
Toshiyuki
T
Department of Genetics, National Research Institute for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo, 157-8535, Japan. tmiyashita@nch.go.jp.
D017398:Alternative Splicing; D019398:Genes, BRCA1; D006367:HeLa Cells; D006801:Humans; D012342:RNA, Small Nuclear / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction
D012342:RNA, Small Nuclear; C405487:U7 small nuclear RNA