miR-133b targets tagln2 and functions in tilapia oogenesis

Area of Science:

• Molecular Biology
• Reproductive Biology
• Aquaculture

Background:

• MicroRNAs (miRNAs) are non-coding RNAs regulating gene expression post-transcriptionally.
• miR-133b is implicated in muscle differentiation and tumorigenesis, with recent studies suggesting a role in estrogen synthesis via foxl2 targeting in mice.
• The function of miR-133b in fish reproduction, particularly oogenesis, remains largely uncharacterized.

Purpose of the Study:

• To investigate the role of miR-133b in tilapia oogenesis.
• To identify target genes of miR-133b involved in fish reproductive processes.
• To elucidate the regulatory network of miR-133b during tilapia ovarian development.

Main Methods:

• Quantitative PCR (qPCR) was used to determine miR-133b expression levels in tilapia ovaries at different developmental stages.
• Antagomir-133b treatment was applied to tilapia to assess the functional impact of miR-133b inhibition on oogenesis.
• Dual luciferase reporter assays were employed to validate tagln2 as a direct target gene of miR-133b.

Main Results:

• miR-133b exhibited high expression in early-stage tilapia ovaries (30 and 90 days after hatching), decreasing in later stages.
• Inhibition of miR-133b led to a significant reduction in oogonia and an unexpected increase in foxl2, cyp19a1a, and estradiol levels.
• Tagln2 was identified and confirmed as a direct target gene of miR-133b and was found to be co-expressed with miR-133b in tilapia ovaries.

Conclusions:

• miR-133b plays a significant role in the early stages of tilapia oogenesis.
• The findings suggest that miR-133b regulates oogenesis, at least partly, through the modulation of tagln2 expression.
• This study contributes to understanding the molecular mechanisms underlying fish oogenesis and provides a basis for further research into reproductive regulatory networks.