IRF-2 is involved in up-regulation of nonmuscle myosin heavy chain II-A gene expression during phorbol ester-induced promyelocytic HL-60 differentiation
IRF-2 is involved in up-regulation of nonmuscle myosin heavy chain II-A gene expression during phorbol ester-induced promyelocytic HL-60 differentiation
复制标题
DOI：
10.1074/jbc.m404791200
复制
发表时间：
2004-12-31
影响因子：
4.8
通讯作者：
Kawamoto, S
中科院分区：
文献类型：
--
作者：
Chung, MC;Kawamoto, S
非肌肉肌球蛋白重链II-A（NMHC-A）基因的转录受多种因素调节，包括细胞类型、增殖和分化阶段以及细胞外刺激。我们已经鉴定了位于人NMHC-A基因转录起始位点下游32 kb的内含子区（命名为32 kb-150）作为转录调控区。32 kb-150含有干扰素刺激的应答元件（ISRE）。利用组成型表达NMHC-A的HeLa细胞和NIH 3 T3细胞，发现干扰素调节因子（IRF）-2是IRF家族中唯一在体外和完整细胞中与32 kb-150的ISRE结合的主要蛋白。已知IRF-2抑制或激活靶基因表达，在32 kb-150报告基因的背景下充当转录激活因子。IRF-2的羧基末端碱性区域在此背景下充当活化结构域。这与其在合成核心ISRE的背景下作为阻遏物结构域的作用相反。此外，在用12-O-十四烷酰基佛波醇-13-乙酸酯（TPA）处理早幼粒细胞HL-60细胞（其触发分化成巨噬细胞）后，发现NMHC-A表达和IRF-2表达均以类似的时间过程上调。TPA处理导致IRF-2募集到内源性NMHC-A基因的32 kb-150，并使该区域周围的核心组蛋白乙酰化。此外，32 kb-150报告基因中的ISRE募集IRF-2并介导TPA诱导的HL-60细胞中报告基因的激活。总之，这些结果表明，在TPA诱导的HL-60细胞分化过程中，IRF-2通过32 kb-150参与NMHC-A基因的转录激活。
Transcription of the nonmuscle myosin heavy chain II-A (NMHC-A) gene is regulated by various factors, including cell type, proliferation and differentiation stage, and extracellular stimuli. We have identified an intronic region (designated 32kb-150), which is located 32 kb downstream of the transcription start sites in the human NMHC-A gene, as a transcriptional regulatory region. 32kb-150 contains an interferon-stimulated response element (ISRE). By using HeLa and NIH3T3 cells, in which NMHC-A is constitutively expressed, interferon regulatory factor (IRF)-2 was found to be the only major protein, among the IRF family proteins, that bound to the ISRE in 32kb-150 both in vitro and in intact cells. IRF-2, which is known to either repress or activate target gene expression, acts as a transcriptional activator in the context of the 32kb-150 reporter gene. The carboxyl-terminal basic region of IRF-2 serves as an activation domain in this context. This is in contrast to its acting as a repressor domain in the context of the synthetic core ISRE. Furthermore, after treatment of promyelocytic HL-60 cells with 12-O-tetradecanoylphorbol-13-acetate (TPA), which triggers differentiation into macrophages, both NMHC-A expression and IRF-2 expression were found to be up-regulated with a similar time course. TPA treatment leads to recruitment of IRF-2 to 32kb-150 of the endogenous NMHC-A gene and acetylation of the core histones surrounding this region. In addition, the ISRE in the 32kb-150 reporter gene recruits IRF-2 and mediates TPA-induced activation of a reporter gene in HL-60 cells. Together, these results indicate that IRF-2 contributes to transcriptional activation of the NMHC-A gene via 32kb-150 during TPA-induced differentiation of HL-60 cells.