A transforming growth factor-beta control element required for SM alpha-actin expression in vivo also partially mediates GKLF-dependent transcriptional repression.
A transforming growth factor-beta control element required for SM alpha-actin expression in vivo also partially mediates GKLF-dependent transcriptional repression.
复制标题
DOI：
--
复制
发表时间：
2003
期刊：
影响因子：
--
通讯作者：
Yan Liu;S. Sinha;G. Owens
中科院分区：
文献类型：
--
作者：
Yan Liu;S. Sinha;G. Owens
我们以前证明，在平滑肌细胞（SMC）分化标记基因SM α-肌动蛋白的5 '区域内的保守的转化生长因子-β控制元件（TCE）可以通过与锌指Kruppel样转录因子（KLF）家族成员的相互作用介导培养的SMC中的转录激活和抑制。本研究的目的是：1）通过转基因小鼠的诱变研究确定SM α-肌动蛋白TCE在体内的作用; 2）进一步表征TCE结合因子GKLF/KLF4在体外各种SMC模型系统中诱导SMC标记基因阻遏的可能作用和机制。我们的研究结果表明，TCE是需要在转基因小鼠体内SM α-肌动蛋白启动子活性。瞬时转染研究的结果表明，GKLF诱导的SM α-肌动蛋白启动子/荧光素酶报告基因的阻遏部分依赖于TCE。此外，GKLF过表达腺病毒抑制，而GKLF吗啉代反义寡核苷酸增加内源性SMC标记基因的表达。染色质免疫沉淀分析结果显示GKLF结合TCE含有各种SMC标记基因启动子的完整染色质内的区域。最后，共转染研究的结果表明，IKLF/KLF5的过表达逆转GKLF依赖的抑制，从而支持一个模型的相互激活-抑制SMC基因表达的不同成员的KLF基因家族。
We previously demonstrated that a conserved transforming growth factor-beta control element (TCE) within the 5'-region of the smooth muscle cell (SMC) differentiation marker gene SM alpha-actin could mediate both transcriptional activation and repression in cultured SMCs through interaction with members of the zinc finger Kruppel-like transcription factor (KLF) family. The aims of the present studies were to: 1) determine the role of the SM alpha-actin TCE in vivo through mutagenesis studies in transgenic mice and 2) further characterize the possible role and mechanisms by which the TCE-binding factor GKLF/KLF4 induces repression of SMC marker genes in various SMC model systems in vitro. Our results showed that the TCE was required for SM alpha-actin promoter activity in transgenic mice in vivo. Results of transient transfection studies showed that GKLF-induced repression of a SM alpha-actin promoter/luciferase reporter gene partially depended on the TCE. Furthermore, a GKLF overexpressing adenovirus inhibited whereas GKLF morpholino antisense oligos increased expression of endogenous SMC marker genes. Results of chromatin immunoprecipitation assays showed GKLF binding to TCE containing regions of various SMC marker gene promoters within intact chromatin. Finally, results of co-transfection studies showed that overexpression of IKLF/KLF5 reversed GKLF-dependent repression thus supporting a model of reciprocal activation-repression of SMC gene expression by different members of the KLF gene family.