Mybl2, downregulated during colon epithelial cell maturation, is suppressed by miR-365

Area of Science:

• Cell Biology
• Molecular Biology
• Genetics

Background:

• Intestinal epithelial cell maturation involves significant gene expression changes.
• Understanding gene regulation during this process is crucial for comprehending intestinal homeostasis and disease.

Purpose of the Study:

• To identify genes downregulated during intestinal epithelial cell maturation.
• To investigate the regulatory mechanisms, particularly microRNA (miRNA) involvement, controlling gene expression in these cells.

Main Methods:

• Utilized immortalized colon cell lines (Caco-2, HT29Cl16E, HT29Cl19A) and in vivo models.
• Identified downregulated transcripts using gene expression analysis.
• Investigated miRNA binding sites in the 3'-untranslated region of target genes.
• Employed reporter gene assays and protein expression analysis to confirm miRNA function.

Main Results:

• Identified 14 common downregulated transcripts during colon cell maturation, including Mybl2 (Myb-related protein B).
• Found that Mybl2 suppression during maturation is not primarily transcriptional but mediated by miRNAs.
• Confirmed a functional miRNA-binding site in the Mybl2 3'-UTR.
• Showed upregulation of specific miRNAs, like hsa-miR-365, which directly suppress Mybl2 protein expression in differentiating cells.

Conclusions:

• MicroRNA silencing is a critical mechanism regulating gene expression in maturing colon epithelial cells.
• A target-centered approach is effective for identifying physiologically relevant miRNAs involved in cell differentiation.
• hsa-miR-365 plays a significant role in suppressing Mybl2 during colon cell maturation.