| Summary: | 碩士 === 國立陽明大學 === 臨床醫學研究所 === 105 === O-GlcNAcylation is a form of post-translational protein modification in which a single N-acetylglucosamine(GlcNAc) is added to serine or threonine residues of nuclear and cytoplasmic proteins. This modificationis involved in regulating metabolism, gene transcription and translation. O-GlcNAcylation is a reversible, dynamic and inducible modification that is catalyzed by two enzymes: O-GlcNAc transferase (OGT) is responsible for the addition and O-GlcNAcase (OGA) mediates the removal of GlcNAc from proteins respectively. In lung cancer, the expression of OGT mRNA and protein is higher in tumor tissues than that in normal tissues, and the high expression of OGT is associated with poorer survival of patients. MicroRNAs (miRNAs) plays an important role in modulating gene expression by regulating mRNA stability or translation efficiency through binding to 3’UTR, and dysregulation of miRNAs is involved in tumor progression. However, the underlying mechanism that regulates OGT expression in lung cancer cells is still unclear. Therefore, we aimed to explore if the OGT gene can be targeted by any miRNAs through its 3’UTR in lung adenocarcinoma cells. Our analysis of the 3’UTR of OGT by luciferase reporter assays revealed that the+3881 to +5482 region in OGT-3’UTR may participate in repressing OGT expression. By using four different algorithms to predict miRNA-mRNA interaction, sixteen miRNAs that may target OGT-3’UTR were obtained. Among these sixteen candidates, we demonstrated that miR-200a-3p could most significantly decrease the luciferase activity expressed from a reporter gene carrying OGT-3’UTR. We also used site-directed mutagenesis to confirm that miR-200a-3p may directly regulateOGT expression through OGT-3’UTR. Moreover, OGT protein levels were repressed upon overexpressing miR-200a-3p.
|
|---|
