Activation of helper T cells results in coordinate expression of a number of cytokines involved in differentiation, proliferation and activation of the haematopoietic system. Granulocyte-macrophage colony stimulating factor (GM-CSF) is one such cytokine, whose increased expression results mostly from increases in transcription. Cis-acting elements with NFkappaB, AP1 and ETS-like binding motifs have been identified in the promoter region of the GM-CSF gene, and are important or essential for transcriptional activity following T cell activation. ETS1 is a transcription factor of the ETS family that is expressed in T cells. We have previously shown that ETS1 can transactivate GM-CSF in Jurkat T cells, but only after the cells have been stimulated by treatment with PMA and ionomycin, agents that mimic T cell activation. Thus we proposed that ETS1, which is expressed constitutively in Jurkat cells, may act in concert with PMA/ionomycin inducible factors. Here we show that ETS1 can transactivate a GM-CSF reporter construct in unstimulated Jurkat cells, providing that either NFkappaB or AP1 transcription factors are supplied by co-transfection. We confirm that binding of endogenous NFkappaB and AP1 is induced following PMA/ionomycin treatment of T cells. Transactivation by ETS1, NFkappaB and AP1 is synergistic, and mutation of the individual binding sites reveals that the transcriptional activities of these factors are interdependent. Our results suggest that constitutive ETS1, and inducible NFkappaB and AP1, cooperate as part of a higher order transcriptional complex in activated T cells.

译文

辅助T细胞的活化导致涉及造血系统分化,增殖和活化的多种细胞因子的协调表达。粒细胞-巨噬细胞集落刺激因子(GM-CSF)就是这样一种细胞因子,其表达增加主要是由于转录增加。具有NFkappaB,AP1和ETS样结合基序的顺式作用元件已经在GM-CSF基因的启动子区域被鉴定出来,并且对于T细胞活化后的转录活性是重要的或必不可少的。 ETS1是ETS家族的转录因子,在T细胞中表达。先前我们已经证明ETS1可以在Jurkat T细胞中激活GM-CSF,但是只有在用PMA和离子霉素处理后,这些细胞才可以模拟T细胞的激活。因此,我们提出在Jurkat细胞中组成性表达的ETS1可能与PMA /离子霉素诱导因子协同作用。在这里,我们证明ETS1可以在未刺激的Jurkat细胞中激活GM-CSF报告基因构建体,前提是NFkappaB或AP1转录因子是通过共转染提供的。我们确认内源性NFkappaB和AP1的结合在TMA的PMA /离子霉素处理后被诱导。 ETS1,NFkappaB和AP1的反式激活是协同的,单个结合位点的突变表明这些因子的转录活性是相互依赖的。我们的结果表明,组成型ETS1和诱导型NFkappaB和AP1在激活的T细胞中作为高阶转录复合物的一部分协同作用。

+1
+2
100研值 100研值 ¥99课程
检索文献一次
下载文献一次

去下载>

成功解锁2个技能,为你点赞

《SCI写作十大必备语法》
解决你的SCI语法难题!

技能熟练度+1

视频课《玩转文献检索》
让你成为检索达人!

恭喜完成新手挑战

手机微信扫一扫,添加好友领取

免费领《Endnote文献管理工具+教程》

微信扫码, 免费领取

手机登录

获取验证码
登录