| Summary: | 碩士 === 慈濟大學 === 分子生物暨人類遺傳學系碩士班 === 99 === Pituitary tumor-transforming gene-1 (PTTG1, also known as Securin) is an oncogene first discovered in rat pituitary tumor cells. It possesses transcriptional activity and is overexpressed in a variety of endocrine-related tumors, especially pituitary, thyroid, breast, ovarian, and uterine tumors. In a microRNA microarray screen, we found mir-7 is highly-expressed in hPTTG1-overexpression cancer cell line, MDA-MB-231. Mir-7 is in the intron that could be spliced from heterogeneous ribonucleoproteins K (hnRNPK) gene. hnRNPK is an abundant protein factor found in the nucleus, cytoplasm, mitochondria, and plasma membrane of the cell. It is one of a family of 20 proteins that are involved in transcription and post-transcriptional messenger RNA metabolism. We used RT-PCR analysis and quantitative reverse transcriptase PCR to validate that hnRNPK and mir-7 are up-regulated. The mechanisms how hPTTG1 regulates hnRNPK is still unknown. To investigate how hnRNPK is regulated by hPTTG1, we used luciferase reporter assays and chromatin immunoprecipitations (ChIP) to analysis up to 3000 bps upstream from transcription start site of the hnRNPK gene and found a hPTTG1 binding site. Our results show that hnRNPK can be directly regulated by hPTTG1. We also used cellular transwell migration assay to analysis the effect of hPTTG1 on the invasion ability of breast cancer cells. The results showed hnRNPK may effect migration in breast cancer cells.
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