Transcriptional activation of vesicular monoamine transporter 2 in the pre-B cell line Ea3.123.
Transcriptional activation of vesicular monoamine transporter 2 in the pre-B cell line Ea3.123.
复制标题
前 B 细胞系 Ea3.123 中囊泡单胺转运蛋白 2 的转录激活。
DOI：
10.1042/bj3370193
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
R. Dimaline
中科院分区：
文献类型：
--
作者：
F. Watson;D. Deavall;J. Macro;R. Kiernan;R. Dimaline
分泌颗粒中单胺的摄取和储存是通过囊泡单胺转运蛋白完成的，囊泡单胺转运蛋白 2 (VMAT2) 可能对体内组胺转运很重要。在本研究中，我们使用前 B 细胞系 Ea3.123 来研究 VMAT2 基因转录激活的机制。在 Ea3.123 细胞中，细胞内钙动员后，VMAT2 mRNA 丰度增加，并且这种增加的 mRNA 表达与 L-组氨酸脱羧酶 mRNA 的变化平行，表明 VMAT2 可能负责将组胺隔离到该细胞系的分泌囊泡中。我们克隆了 VMAT2 基因的 5' 侧翼区域，并通过大鼠 VMAT2 mRNA 的引物延伸确定了其转录起始位点。该区域上游不存在TATA或TATA样序列；相反，有富含 GC 的元件、Ca2+/cAMP 响应元件和 SP1 结合基序。大约。转录起始位点上游900bp处是嘌呤-嘧啶重复序列，可能形成Z-DNA结构。克隆在荧光素酶报告基因上游的一系列 5'-缺失 VMAT2 启动子片段能够驱动转录，并表明存在多个调控元件，而用离子霉素或 PMA 刺激会导致所研究的 5'-启动子片段的转录活性水平增加。
Uptake and storage of monoamines in secretory granules is accomplished by vesicular monoamine transporters, and it is likely that vesicular monoamine transporter 2 (VMAT2) is important for histamine transport in vivo. In the present study we have used the pre-B-cell line Ea3.123 to investigate the mechanisms involved in the transcriptional activation of the VMAT2 gene. In Ea3.123 cells, VMAT2 mRNA abundance was increased following mobilization of intracellular calcium, and this increased mRNA expression was paralleled by changes in l-histidine decarboxylase mRNA, suggesting that VMAT2 may be responsible for sequestration of histamine into secretory vesicles in this cell line. We cloned the 5'-flanking region of the VMAT2 gene and determined its transcriptional start site by primer extension of rat VMAT2 mRNA. There was no TATA or TATA-like sequence upstream of this region; instead there were GC-rich elements, Ca2+/cAMP-response-element- and SP1-binding motifs. Approx. 900 bp upstream of the transcriptional start site was a purine-pyrimidine repeat sequence that may form a Z-DNA structure. A series of 5'-deletional VMAT2-promoter segments cloned upstream of a luciferase reporter were capable of driving transcription and indicated the presence of multiple regulatory elements, while stimulation with ionomycin or PMA resulted in an increased level of the transcriptional activity of the 5'-promoter segments studied.