| Summary: | 碩士 === 國立中興大學 === 生命科學系所 === 97 === FTSJ2 is a homologous protein of ribosomal RNA large subunit methyltransferase J (RrmJ) from bacteria. It may function as RrmJ that could catalyze S-adenosylhomocysteine (SAH) converted from demethylation of S-adenosylmethionine (SAM). Methionine adenosyltransferase (MAT) catalyzed the methionine and ATP to produce a principle biological methyl donor, SAM. There are two gene in MAT, MAT1A and MAT2A. It is known that the expression of MAT1A was level down in hepatocellular carcinoma (HCC), but MAT2A was increase. The MAT2A is also a negative control of intracellular SAM level. The functions of FTSJ2 are largely unknown, it is proposed that enhancement of FTSJ2 methyltransferase level may stimulate the MAT activity and SAH content in the cells. In this study, we overexpressed porcine FTSJ2 in HCC cell line HepG2 (G2-FTSJ2) and neuroblastoma cell line te671 (te671-FTSJ2) to prove the correlation between FTSJ2 and MAT. RT-PCR and Western blot were performed to analyze the expressions of MAT1a, MAT2a, SAH hydroase (SAHH), Methionine synthase (MS) and Batine-Homocysetine methyltransferase (BHMT) genes. Data showed that the expressions of MAT1A was 1.3 fold in G2-FTSJ2 than in HepG2 and Huh7. Contrary, MAT2A showed down regulation in G2-FTSJ2 than in HepG2 and Huh7 cell. Interestingly, overexpressed FTSJ2 in te671 cell decreased transcription of SAHH without affecting the RNA level of MAT1A and MAT2A. Our Results showed that FTSJ2 could participate in SAM metabolism cycle by affected the MAT and SAHH. In conclusion, the porcine FTSJ2 protein exhibits the potential function as methyltransferase in eukaryotic cells, especially responsible for abnormal methionine metabolism in HCC and neuroblastoma cell lines.
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