Role of the transcription factor Sp1 in regulating the expression of the murine cathepsin E gene
Role of the transcription factor Sp1 in regulating the expression of the murine cathepsin E gene
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DOI：
10.1093/jb/mvr135
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发表时间：
2012-03-01
影响因子：
2.7
通讯作者：
Yamamoto, Kenji
中科院分区：
文献类型：
--
作者：
Okamoto, Kuniaki;Okamoto, Yoshiko;Yamamoto, Kenji
组织蛋白酶E （Cathepsin E， CE）是一种细胞内的天冬氨酸蛋白酶，仅在胃肠道、淋巴组织、泌尿器官和红细胞中表达。然而，CE在这些细胞中主要表达的分子机制尚不清楚。在这里，我们报道了胃腺肉瘤细胞中CE基因的几个转录起始位点及其调控因子的鉴定。我们首先通过寡核苷酸帽方法确定了小鼠CE基因中几个独特的转录起始位点。他们的分析还揭示了CE基因外显子1上游24kb的非编码区域的存在，以及CE的两个转录本的存在。外显子1上游的荧光素酶分析显示，该位点含有CE基因表达必需的转录因子Sp1、AP-1和cet -1的推定结合区。此外，电泳迁移位移分析显示Sp1位点的蛋白寡核苷酸复合物被抗Sp1抗体超移。染色质免疫沉淀实验显示Sp1与CE启动子区结合。此外，Sp1蛋白的过表达增加了CE蛋白的表达。综上所述，这些结果表明Sp1结合在CE基因表达调控中起着特别重要的作用。
Cathepsin E (CE) is an intracellular aspartic proteinase that is exclusively expressed in cells of the gastrointestinal tracts, lymphoid tissues, urinary organs and red blood cells. However, the molecular mechanism by which CE is predominantly expressed in these cells remains unknown. Here, we report the identification of several transcription start sites of the CE gene and their regulatory factors in gastric adenosarcoma cells. We first identified several unique transcription start sites in mouse CE genes by an oligo cap method. Their analysis also revealed the existence of a non-coding region similar to 24-kb upstream of exon 1 in the CE gene and also the existence of two transcripts for CE. Luciferase analyses in upstream of exon 1 revealed that this site contained putative binding regions for the transcription factors Sp1, AP-1 and cEts-1 essential for the expression of CE gene. Moreover, electrophoretic mobility shift assays revealed that the protein-oligonucleotides complex of the Sp1 site were supershifted by an anti-Sp1 antibody. The chromatin immunoprecipitation assay showed that Sp1 bound to the CE promoter region. In addition, overexpression of the Sp1 protein increased the expression of the CE protein. Altogether, these results suggest that Sp1 binding plays a particularly important role in the regulation of CE gene expression.