期刊
DNA AND CELL BIOLOGY
卷 19, 期 2, 页码 79-91出版社
MARY ANN LIEBERT, INC
DOI: 10.1089/104454900314591
关键词
-
资金
- NCI NIH HHS [CA 36481] Funding Source: Medline
Cathepsin B expression is increased at both the mRNA and protein levels in a wide variety of tumors. The mechanisms responsible for this regulation are not well elucidated. We have isolated a 2.2-kb cathepsin B genomic fragment that contains the 5'-flanking region of the cathepsin B gene. Using reporter gene analysis in human glioblastoma U87MG cells, we have mapped a 228-bp fragment (-172 to +56) having high promoter activity. This promoter region has a high G+C content; contains potential Spl, Ets, and USF binding motifs; and lacks canonical TATA and CAAT boxes immediately upstream of the major transcriptional initiation site. Cotransfection experiments demonstrated that Sp1 and Ets1 could trans-activate cathepsin B transcription,whereas Ets2 could not. Electrophoretic mobility shift assays and supershift assays revealed that three of the four putative Sp1 sites in this promoter region form a specific complex containing the Spl transcription factor. Mutating all four of the Sp1 binding sites individually markedly reduced the promoter activity of transfected reporter genes in U87 cells. Cotransfection of this cathepsin B promoter construct with Sp1 family expression vectors in Schneider's Drosophila line 2 (SL2) cells demonstrated that Sp1 and Sp3, but not Sp3, activated cathepsin B transcription. Taken together, these results suggest that Sp1, Sp3, and Ets1 are important factors in cathepsin B transcription. The regulation of cathepsin B transcription by Sp1- and Sp1-related factors is mediated through multiple GC boxes.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据