Differential expression patterns of conserved miRNAs and isomiRs during Atlantic halibut development

Area of Science:

• Developmental biology
• Molecular biology
• Genomics

Background:

• MicroRNAs (miRNAs) are key regulators of animal development.
• IsomiRs, miRNA size variants, have unclear origins and functions.
• Atlantic halibut (Hippoglossus hippoglossus L.) undergo significant metamorphosis, with limited knowledge of miRNA roles.

Purpose of the Study:

• To investigate miRNA and isomiR expression profiles during Atlantic halibut early development and metamorphosis.
• To identify developmental transition-specific miRNA expression patterns.
• To explore the role of isomiRs in halibut development.

Main Methods:

• Deep sequencing (SOLiD) for miRNA profiling.
• Reverse transcription quantitative PCR (RT-qPCR) for expression validation.
• Cloning and Sanger sequencing for isomiR confirmation.

Main Results:

• Identified 199 conserved miRNAs, one novel antisense miRNA, and one miRNA*.
• Observed developmental transition-specific miRNA expression.
• Revealed differential expression patterns of isomiRs due to nucleotide variations, with some miRNA* exceeding guide strand levels.
• Confirmed an inverse relationship between sense/antisense miRNA expression.

Conclusions:

• Specific microRNAs are associated with developmental transitions in Atlantic halibut.
• IsomiRs are prevalent and exhibit differential expression during development, suggesting functional significance.