Molecular mechanisms of human single-minded 2 (SIM2) gene expression:: identification of a promoter site in the SIM2 genomic sequence
Molecular mechanisms of human single-minded 2 (SIM2) gene expression:: identification of a promoter site in the SIM2 genomic sequence
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DOI：
10.1016/s0378-1119(01)00450-4
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发表时间：
2001-05-30
期刊：
影响因子：
3.5
通讯作者：
Shimizu, Y
中科院分区：
文献类型：
--
作者：
Yamaki, A;Tochigi, J;Shimizu, Y
我们先前假设，在人类染色体21q22.2上鉴定的专一2（SIM 2）基因是唐氏综合征智力低下发病机制的良好候选基因，因为其小鼠同源物在胚胎发育早期在小鼠间脑中表现出优先表达。我们分析了整个SIM 2基因的基因组序列，该基因由ii个外显子组成，跨度超过50 kb。作为理解SIM 2基因表达的分子机制的一步，我们分析了9个已建立的人类细胞系中的人类SIM 2基因表达。三份成绩单分别是3.6和4.4.在胶质母细胞瘤细胞系T98 G、神经母细胞瘤细胞系中检测到约6.0kb。TGW和转化的胚肾细胞系，293。利用SIM 2表达的人细胞系T98 G进行的RACE分析提供了转录起始位点在翻译起始位点上游1.2kb附近的证据。使用具有报告基因的各种缺失构建体的转染测定表明存在推定的启动子区域。T98 G细胞瞬时转染实验表明，该基因启动子位于翻译起始位点上游nt - 1385和-1325之间的60 bp序列中。该60 bp序列含有c-myb、E47和E2 F转录因子的顺式元件。此外，使用各种cia元件序列的寡聚DNA的凝胶阻滞测定表明存在与c-myb的顺式元件结合的蛋白因子。这些结果表明，蛋白质转录因子如c-myb或类似物的结合通过结合到小的上游区域来调节SIM 2基因的转录。(C)2001 Elsevier Science B. V.保留所有权利。
We previously postulated that the single-minded 2 (SIM2) gene identified on the human chromosome 21q22.2 is a good candidate gene for the pathogenesis of mental retardation in Down syndrome because its mouse homolog exhibits preferential expression in the mouse diencephalon during early embryogenesis. We analyzed the genomic sequence of the entire SIM2 gene which consists of ii exons and spans over 50 kb. As a step toward understanding the molecular mechanisms of SIM2 gene expression, we have analyzed the human SIM2 gene expression in nine established human cell lines. Three transcripts of 3.6, 4.4. and 6.0 kb were detected in the glioblastoma cell line, T98G, neuroblastoma cell line. TGW, and transformed embryonic kidney cell line, 293. The RACE analysis using SIM2-expressing human cell line T98G provided evidence for the transcription start site at similar to1.2 kb upstream of the translation initiation site. The transfection assay using various deletion constructs with reporter gene suggested the presence of a presumptive promoter region. Transient transfection assay in T98G cell line revealed a significant promoter activity located in the 60 bp sequence between nt - 1385 and - 1325 upstream region of the translation initiation site. This 60 bp sequence contains cis-elements for c-myb, E47 and E2F transcription factors. Moreover, the gel retardation assay using oligo-DNA of various cia-element sequences indicated the presence of protein factor(s) which bind to the cis-element for c-myb. These results suggested that binding of a protein transcription factor(s) such as c-myb or that alike regulates transcription of the SIM2 gene by binding to a small upstream region. (C) 2001 Elsevier Science B.V. All rights reserved.