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Genome-wide Screen for miRNA Targets Using the MISSION Target ID Library
Published on: April 6, 2012
The MUC1 and galectin-3 oncoproteins function in a microRNA-dependent regulatory loop
Selvi Ramasamy1, Sekhar Duraisamy, Sergei Barbashov
1Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA.
Molecular Cell
|September 25, 2007
Summary
Mucin 1 (MUC1) protein upregulates galectin-3 expression in human carcinomas by suppressing microRNA miR-322. This interaction is crucial for MUC1 and epidermal growth factor receptor (EGFR) signaling in cancer.
Area of Science:
- Oncology
- Molecular Biology
- Biochemistry
Background:
- Mucin 1 (MUC1) is a transmembrane glycoprotein overexpressed in various human carcinomas.
- Galectin-3, a beta-galactoside binding protein, is implicated in human cancer development.
Purpose of the Study:
- To elucidate the regulatory mechanism by which MUC1 influences galectin-3 expression.
- To investigate the role of MUC1 glycosylation and its interaction with galectin-3 in cancer signaling.
Main Methods:
- Posttranscriptional regulation analysis.
- MicroRNA (miRNA) expression profiling.
- Glycosylation site identification (Asn-36).
- Protein-protein interaction assays (MUC1, galectin-3, EGFR).
Main Results:
- MUC1 upregulates galectin-3 expression via a posttranscriptional mechanism.
- Glycosylation of MUC1 C-terminal subunit at Asn-36 is essential for galectin-3 upregulation.
- N-glycosylated MUC1-C suppresses miR-322, stabilizing galectin-3 mRNA.
- Galectin-3 binds to glycosylated MUC1-C at Asn-36.
- Galectin-3 bridges MUC1 and EGFR, mediating EGF-induced interactions.
Conclusions:
- MUC1 and galectin-3 form a regulatory loop dependent on miR-322.
- This MUC1-galectin-3-EGFR axis plays a significant role in cancer progression.
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