Rat BodyMap transcriptomes reveal unique circular RNA features across tissue types and developmental stages

Area of Science:

• Genomics
• Molecular Biology
• Biochemistry

Background:

• Circular RNAs (circRNAs) are a newly identified class of regulatory RNA molecules.
• Their expression patterns and functional significance across different tissues and developmental stages are not fully understood.

Purpose of the Study:

• To comprehensively investigate circRNA expression profiles in rats across multiple tissues and developmental stages.
• To perform cross-species comparisons of circRNA expression with humans and mice.
• To explore the functional implications of tissue- and age-specific circRNA expression.

Main Methods:

• RNA sequencing to profile circRNA expression.
• Comparative analysis of circRNA and mRNA expression.
• Tissue and developmental stage analysis in rats, humans, and mice.

Main Results:

• circRNA expression is generally correlated with cognate mRNA levels, but highly expressed genes produce a larger fraction of circular transcripts.
• circRNAs display higher tissue specificity compared to their cognate mRNAs.
• Rat brain circRNA abundance increases monotonically with age.
• Rat testicular circRNA expression shows a dynamic pattern, increasing during sexual maturation and decreasing with aging, with age-sensitive circRNAs linked to spermatogenesis independently of mRNA.

Conclusions:

• circRNAs exhibit unique tissue and age-dependent expression patterns.
• These patterns suggest distinct physiological roles for circRNAs beyond being transcriptional by-products.
• circRNAs, especially in the testes, are dynamically regulated and functionally associated with specific biological processes like spermatogenesis.