A challenge for miRNA: multiple isomiRs in miRNAomics

Area of Science:

• Molecular Biology
• Genetics
• Bioinformatics

Background:

• A single microRNA (miRNA) locus can generate multiple related sequences during its maturation.
• These miRNA variants, termed isomiRs, exhibit variations in length and nucleotide sequences at their 5' and 3' ends.
• Some isomiRs also feature non-templated nucleotide additions at the 3' end.

Purpose of the Study:

• To review the biogenesis of miRNA and isomiRs.
• To explore the expression patterns of isomiRs.
• To discuss the functional and evolutionary implications of isomiRs, particularly in comparison to homologous and clustered miRNA loci.

Main Methods:

• Literature review focusing on miRNA and isomiR biogenesis.
• Analysis of published data on isomiR expression patterns.
• Comparative analysis of functional and evolutionary aspects of isomiRs.

Main Results:

• Evidence indicates that miRNA loci produce a series of isomiRs with diverse characteristics.
• IsomiRs are recognized as physiological isoforms with potential regulatory roles.
• Expression patterns and functional implications vary among different isomiRs.

Conclusions:

• The existence of multiple isomiRs highlights the complexity of miRNA biogenesis.
• Incorporating isomiR analysis into miRNA studies is essential for a comprehensive understanding.
• IsomiRs significantly enrich and potentially complicate miRNA biogenesis and regulatory networks.