Mismatched and wobble base pairs govern primary microRNA processing by human Microprocessor

Area of Science:

• Molecular Biology
• Genetics
• Biochemistry

Background:

• MicroRNAs (miRNAs) are crucial regulators of gene expression.
• The Microprocessor complex is essential for processing primary miRNAs (pri-miRNAs) into mature miRNAs.
• Understanding Microprocessor's catalytic mechanism is vital for comprehending miRNA biogenesis and function.

Purpose of the Study:

• To investigate the catalytic mechanism of Microprocessor in cleaving pri-miRNAs.
• To identify RNA structural elements within pri-miRNAs that influence Microprocessor processing.
• To explore how RNA modifications and genetic variations affect miRNA production.

Main Methods:

• High-throughput enzymatic assays were employed to study Microprocessor activity.
• Randomized pri-miRNAs were used to probe the enzyme's catalytic mechanism.
• Analysis of RNA structural elements, including mismatches and wobble base pairs, in pri-miRNA substrates.

Main Results:

• Multiple mismatches and wobble base pairs in the upper stem of pri-miRNAs were identified as key determinants of processing efficiency and accuracy.
• These RNA elements explain alternative cleavage patterns observed for some human pri-miRNAs.
• RNA-editing events and single nucleotide polymorphisms (SNPs) were shown to alter pri-miRNA processing by modifying these RNA elements.

Conclusions:

• The study elucidates the role of specific RNA structural features in pri-miRNA processing by Microprocessor.
• Findings provide a mechanistic basis for understanding how RNA modifications and genetic variations lead to differential miRNA expression.
• This work enhances the understanding of miRNA biogenesis regulation and its implications in disease.