Transcriptional regulation of the human alpha 2(I) collagen gene - Combined action of upstream stimulatory and inhibitory cis-acting elements
Transcriptional regulation of the human alpha 2(I) collagen gene - Combined action of upstream stimulatory and inhibitory cis-acting elements
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DOI：
10.1074/jbc.271.43.26717
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发表时间：
1996-10-25
影响因子：
4.8
通讯作者：
Trojanowska, M
中科院分区：
文献类型：
--
作者：
Ihn, H;Ohnishi, K;Trojanowska, M
这项研究确定了三个区域的人α 2（I）胶原蛋白启动子参与核因子的结合。这些区域包括-173至-155（足迹I）、-133至-119（足迹II）和-101至-72（足迹III）的序列。一个新的积极的顺式元件包含TCCTCC基序内足迹II确定。此外，我们证明了足迹I内的富含嘧啶的区域是转录抑制因子的结合位点，足迹III内的CCAAT基序是转录激活因子的结合位点。对该启动子近端350个碱基对内的顺式作用元件进行了比较功能分析，包括先前表征的-300处的Sp1结合位点，表明该启动子的组成型活性受到-300、-125和-80处的三个正顺式作用元件的同等调节。阻遏物位点-160处的突变使组成型活性增加4-6倍。然而，阻遏物位点和顺式调节元件在-300或-125位点的同时突变导致组成型转录活性没有增加，表明激活子和阻遏物元件之间的相互作用。相反，CCAAT基序和阻遏物位点的同时突变导致约4倍的增加，提示通过CCAAT基序的激活可能不依赖于该阻遏物。
This study identifies three regions of the human alpha 2(I) collagen promoter involved in the binding of nuclear factors. These regions include sequences from -173 to -155 (footprint I), -133 to -119 (footprint II), and -101 to -72 (footprint III). A novel positive cis-element containing a TCCTCC motif was identified within footprint II. In addition, we demonstrated that a pyrimidine-rich region within footprint I is a binding site for a transcriptional repressor, and a CCAAT motif within footprint III is a binding site for a transcriptional activator, Comparative functional analysis of the cis-acting elements within the proximal 350 base pairs of this promoter, including previously characterized Sp1 binding sites at -300, indicates that constitutive activity of this promoter is regulated equivalently by the three positive cis-acting elements at -300, -125, and -80. Mutations in the repressor site at -160 increase constitutive activity by 4-6 fold. However, simultaneous mutations of the repressor site and the cis-regulatory element at either the -300 or -125 sites result in no increase in constitutive transcription activity suggesting interaction between the activators and repressor elements, In contrast, simultaneous mutation of the CCAAT motif and the repressor site results in about a 4-fold increase, suggesting that activation via the CCAAT motif may be independent of this repressor.