Enzymatic Character and Promoter Assay of Nap1 gene

• Main Authors: Jyun-Hong Lyu, 呂俊宏
• Other Authors: Chin-Hsiang Chien
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/54955175591290888857

碩士 === 國立陽明大學 === 生化暨分子生物研究所 === 97 === NAP1 is known as a putative tumor suppressor. Few studies have described the enzyme function and gene regulation until recent three years. Previous studies demonstrated that human Nap1 showed low nitrilase activity. In this study, human Nap1 with ω-amidase activity was determined. Human Nap1 catalyzed α-ketoglutarmate and succinamate to corresponding hydroxamate under acyl-transfer reaction. The ω-amidase activity can be inhibited competitively by glycylglycine and irreversibly inhibited by iodoacetamide. To understand transcriptional regulation of NAP1 promoter, we applied a NAP1 promoter clone with luciferase tag. Luciferase assay results show high basal NAP1 promoter activity in Huh7 cell. Sequence analysis of the promoter region among many species exhibited several putative transcription factor binding sites for Sp1. Treatment of Huh7 cell with mithramycin A resulted to reduce the NAP1 gene expression and transcriptional level. It indicates that Sp1 activate NAP1 gene. To investigate the Sp1-mediated NAP1 activation, we treated Huh7 cell with TGF-β and trichostatin A (TSA), a histone deacetylase inhibitor. Unexpected results showed no obvious increase of NAP1 gene expression by TGF-β and showed inhibitory effect by TSA. The signaling pathway of Sp1-mediated NAP1 gene expression is still unclear.