PU.1 (Spi-1) autoregulates its expression in myeloid cells.
PU.1 (Spi-1) autoregulates its expression in myeloid cells.
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发表时间：
1995-10
期刊：
影响因子：
8
通讯作者：
H. Chen;D. Ray-Gallet;P. Zhang;C. Hetherington;D. Gonzalez;D. Zhang;F. Moreau-Gachelin;D. Tenen
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作者：
H. Chen;D. Ray-Gallet;P. Zhang;C. Hetherington;D. Gonzalez;D. Zhang;F. Moreau-Gachelin;D. Tenen
PU.1 (Spi-1) 是 Ets 转录因子家族的成员，主要在骨髓细胞（粒细胞、单核细胞和巨噬细胞）和 B 细胞中表达。 PU.1 在多能祖细胞向骨髓谱系定型期间早期上调，并且在这种上调阻止骨髓集落形成之前抑制人 CD34+ 祖细胞中的 PU.1 功能。由于 PU.1 表达似乎在造血发育中发挥作用，因此我们对 PU.1 启动子进行了表征。在此，我们报道小鼠 PU.1 启动子以及人类启动子在骨髓细胞系中表现出组织特异性报告基因表达，但在 T 细胞和 HeLa（非造血细胞）细胞中则不然。 PU.1启动子的缺失分析表明，组织特异性功能元件编码在-61至-39 bp和-7至+34 bp区域中。第一个区域包含位于 -54 bp 的功能八聚体 (Oct) 位点和位于 -39 bp 的 Sp1 位点。第二个在 +20 bp 处包含 PU.1 本身和相关 ets 家族成员 Spi-B 的结合位点。体内足迹分析表明，在骨髓细胞的 PU.1 位点检测到超敏带，但在 HeLa 中未检测到。 PU.1 位点的突变导致 PU.1 结合失效，导致启动子活性显着降低。 Oct 和/或 Sp1 位点的突变导致骨髓细胞中启动子活性的较小程度降低。在缺乏 PU.1 和 Spi-B 的细胞中共转染 PU.1 或 Spi-B 特异性反式激活含有 PU.1 结合位点的最小启动子，表明 PU.1 可以在自动调节环中激活其自身的启动子元件。 PU.1 启动子的正向自动调节可能在 PU.1 在骨髓细胞中的功能中发挥重要作用。
PU.1 (Spi-1), a member of the Ets transcription factor family, is predominantly expressed in myeloid (granulocytes, monocytes and macrophages) and B cells. PU.1 is upregulated early during commitment of multipotential progenitors to the myeloid lineages and inhibition of PU.1 function in human CD34+ progenitors prior to this upregulation blocks myeloid colony formation. Since PU.1 expression appears to play a role in hematopoietic development, we characterized the PU.1 promoter. Here we report that the murine PU.1 promoter, as well as the human promoter, demonstrate tissue-specific reporter gene expression in myeloid cell lines but not in T cells and HeLa (non-hematopoietic cells) cells. Deletion analysis of the PU.1 promoter indicates that tissue-specific functional elements are encoded in the -61 to -39 bp and -7 to +34 bp regions. The first region contains a functional octamer (Oct) site at -54 bp and an Sp1 site at -39 bp. The second contains a binding site at +20 bp for both PU.1 itself and the related ets family member Spi-B. In vivo footprinting assays demonstrate that a hypersensitive band was detected at the PU.1 site in myeloid cells but not in HeLa. A mutation of the PU.1 site which abolished PU.1 binding caused a significant decrease in promoter activity. Mutation of the Oct and/or Sp1 site results in a lesser decrease of promoter activity in myeloid cells. Co-transfection of PU.1 or Spi-B in cells lacking PU.1 and Spi-B specifically transactivated a minimal promoter containing the PU.1 binding site, indicating that PU.1 can activate its own promoter elements in an autoregulatory loop. Positive autoregulation of the PU.1 promoter may play an important role in the function of PU.1 in myeloid cells.