miR-31-mediated local translation at the mitotic spindle is important for early development

Area of Science:

• Molecular Biology
• Developmental Biology
• Cell Biology

Background:

• MicroRNAs (miRNAs) are key regulators of gene expression.
• miR-31 is a conserved miRNA involved in cell proliferation, migration, and differentiation.
• The precise role of miR-31 during mitosis is not fully understood.

Purpose of the Study:

• To investigate the role of miR-31 in cell division.
• To determine the localization and function of miR-31 at the mitotic spindle.
• To identify miR-31 targets involved in cytoskeletal regulation during mitosis.

Main Methods:

• Utilized sea urchin embryos as a model system for studying cell division.
• Employed techniques to inhibit miR-31 function and observe developmental outcomes.
• Identified and validated miR-31 targets using molecular and imaging methods.
• Investigated the localization and translation of Fascin at the mitotic spindle.

Main Results:

• miR-31 and its targets are enriched on the mitotic spindle in both sea urchin embryos and mammalian cells.
• Inhibition of miR-31 resulted in developmental delays and increased cytoskeletal/chromosomal defects.
• miR-31 directly suppresses actin remodeling transcripts, including Fascin.
• miR-31 inhibition led to increased Fascin translation at the mitotic spindle.
• Ectopic Fascin localization caused significant developmental and chromosomal segregation defects.

Conclusions:

• miR-31 plays a critical role in regulating local translation of actin remodeling proteins at the mitotic spindle.
• This regulation by miR-31 is essential for proper cell division and chromosomal segregation.
• miR-31-mediated post-transcriptional regulation at the mitotic spindle represents an evolutionarily conserved mechanism in mitosis.