MicroRNA-222 regulates muscle alternative splicing through Rbm24 during differentiation of skeletal muscle cells

Area of Science:

• Molecular Biology
• Developmental Biology
• Genetics

Background:

• MicroRNAs (miRNAs) are crucial regulators of skeletal muscle development and differentiation.
• MicroRNA-222 (miR-222) is observed to be downregulated during myogenesis, and its overexpression disrupts muscle differentiation and specialized structures.

Purpose of the Study:

• To identify novel targets of miR-222 involved in myogenic differentiation.
• To elucidate the mechanism by which miR-222 regulates muscle differentiation.

Main Methods:

• RNA-induced silencing complex (RISC) pulldown assay followed by RNA sequencing.
• In silico miRNA target prediction analysis.
• Cellular assays to assess muscle differentiation and splicing.

Main Results:

• Two new targets of miR-222, Ahnak and Rbm24, were identified.
• Downregulation of the RNA-binding protein Rbm24 by miR-222 impairs muscle-specific alternative splicing, affecting transcripts like Coro6, Fxr1, and NACA.
• Restoring Rbm24 levels rescued the splicing defects in cells overexpressing miR-222.

Conclusions:

• MicroRNA-222 plays a novel role in regulating myogenic differentiation by affecting alternative splicing.
• This effect is mediated through the downregulation of Rbm24, highlighting a new regulatory pathway in muscle development.