MicroRNA Transcriptomes Reveal Prevalence of Rare and Species-Specific Arm Switching Events During Zebrafish...

Area of Science:

• Molecular Biology
• Genetics
• Developmental Biology

Background:

• MicroRNAs (miRNAs) are crucial gene expression regulators in metazoans, impacting cellular processes like differentiation and homeostasis.
• Variations in miRNA biogenesis, specifically "arm switching" where either the 5p or 3p arm loads onto the RISC complex, can alter gene targeting and biological pathway modulation.

Purpose of the Study:

• To investigate the impact of miRNA arm switching events on gene regulation across diverse tissues and developmental stages.
• To compare arm switching dynamics in zebrafish with other vertebrate species (fish, birds, mammals).

Main Methods:

• Analysis of miRNA 5p and 3p arm accumulation dynamics in zebrafish across embryonic stages, adult tissues, and sexes.
• Comparative analysis of arm switching patterns between zebrafish and other vertebrates.

Main Results:

• Variable miRNA arm usage events were found to predominantly occur during embryonic development.
• IsomiR occurrence correlates with changes in miRNA arm selection, indicating a role for distinct miRNA isoforms in gene regulation.
• Switches in miRNA 5p and 3p arm accumulation dynamics were observed, reinforcing and modifying gene regulation.

Conclusions:

• MiRNA arm switching is a significant mechanism influencing gene expression, particularly during embryonic development.
• Distinct miRNA isoforms and their arm usage dynamics play a role in fine-tuning gene regulation.
• The study provides insights into the emergence and coordination of gene expression regulation through miRNA dynamics.