U7 snRNA-mediated correction of aberrant splicing caused by activation of cryptic splice sites

Area of Science:

• Molecular Biology
• Genetics
• RNA Biology

Background:

• Splicing mutations are implicated in numerous hereditary disorders and cancers.
• Cryptic splice site activation leads to aberrant splicing, including exon skipping or intronic sequence inclusion.
• Targeting these cryptic sites is crucial for understanding and potentially treating splicing-related diseases.

Purpose of the Study:

• To design and test modified U7 small nuclear RNAs (snRNAs) to suppress cryptic splice sites.
• To investigate the efficacy of engineered U7 snRNAs in correcting splicing defects in specific disease-associated genes.

Main Methods:

• Designed vectors expressing modified U7 snRNAs with antisense sequences targeting cryptic splice sites.
• Investigated three mutation cases in PTCH1, BRCA1, and CYP11A genes.
• Performed transient expression of engineered U7 snRNAs in HeLa cells to assess splicing correction.

Main Results:

• Engineered U7 snRNAs restored correct splicing in PTCH1 and BRCA1 gene mutations in a sequence-specific and dose-dependent manner.
• In a CYP11A mutation case, modified U7 snRNA expression led to exon skipping, indicating context-dependent outcomes.
• Suppression of intronic cryptic splice sites with U7 snRNA demonstrated successful correction of aberrant splicing.

Conclusions:

• Modified U7 snRNAs are effective tools for sequence-specific suppression of aberrant splicing caused by intronic cryptic splice sites.
• This strategy shows promise as an alternative therapeutic approach to gene replacement therapy for splicing-related disorders.
• Further research is warranted to explore the full therapeutic potential of U7 snRNA-based splicing correction.