miRNA gene mutations commonly disrupt the proper functioning of miRNA genes

Area of Science:

• Genomics
• Molecular Biology
• Cancer Research

Background:

• Noncoding genome mutations, including in microRNA (miRNA) genes, are increasingly identified.
• The functional consequences and pathogenicity of miRNA gene mutations remain largely unknown.

Purpose of the Study:

• To evaluate the effects of somatic mutations in miRNA genes on miRNA function.
• To assess the impact of these mutations on miRNA levels, processing, and precursor stability.

Main Methods:

• Analysis of >10,000 The Cancer Genome Atlas (TCGA) cancer samples.
• Comparison of somatic mutations in miRNA genes with miRNA sequencing data.
• Application of rigorous statistical criteria to identify deleterious mutations.

Main Results:

• A significant fraction of miRNA gene mutations negatively impacts miRNA function.
• Mutations affect mature miRNA levels, isomiR profiles (DROSHA/DICER1 cleavage precision), and 5p/3p strand balance.
• Most mutations, particularly deleterious ones, destabilize miRNA precursor structures.

Conclusions:

• Many miRNA gene mutations can impair miRNA gene function.
• Deleterious mutations in disease-related miRNA genes may represent pathogenic variants.
• Understanding miRNA mutations is crucial for cancer genomics and genetic disease research.