Direct interaction of hematopoietic transcription factors PU.1 and GATA-1: functional antagonism in erythroid cells
Direct interaction of hematopoietic transcription factors PU.1 and GATA-1: functional antagonism in erythroid cells
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DOI：
10.1101/gad.13.11.1398
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发表时间：
1999-06-01
影响因子：
10.5
通讯作者：
Skoultchi, AI
中科院分区：
文献类型：
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作者：
Rekhtman, N;Radparvar, F;Skoultchi, AI
恶性转化通常抑制终末细胞分化，但涉及的确切机制尚不清楚。PU.1是造血特异性Ets家族转录因子，其是某些淋巴和骨髓谱系发育所需的。PU.1也可以作为癌蛋白，因为通过前病毒插入或转基因激活其在红系前体中的表达会导致小鼠的红白血病。小鼠红白血病（MEL）细胞终末分化的恢复需要PU.1水平的下降，表明PU.1可以阻断红系分化。在这里，我们调查PU.1干扰红细胞分化的机制。我们发现PU.1直接与红系分化所需的锌指转录因子加塔-1相互作用。PU.1和加塔-1之间的相互作用需要两种蛋白质中的完整DNA结合结构域。PU.1抑制加塔-1介导的转录激活。PU.1的DNA结合和反式激活结构域都是阻遏所必需的，并且这两个结构域也是阻断MEL细胞中的终末分化所必需的。我们还表明，在爪蟾胚胎中的PU.1的异位表达足以阻止正常发育过程中的红细胞生成。此外，在MEL细胞和非洲爪蟾胚胎和外植体中引入外源性加塔-1缓解了PU. 1对红系分化的阻断。我们的研究结果表明，化学计量的直接相互作用，但相反的转录因子可能是一个重要的决定因素，正常分化和恶性转化的过程。
Malignant transformation usually inhibits terminal cell differentiation but the precise mechanisms involved are not understood. PU.1 is a hematopoietic-specific Ets family transcription factor that is required for development of some lymphoid and myeloid lineages. PU.1 can also act as an oncoprotein as activation of its expression in erythroid precursors by proviral insertion or transgenesis causes erythroleukemias in mice. Restoration of terminal differentiation in the mouse erythroleukemia (MEL) cells requires a decline in the level of PU.1, indicating that PU.1 can block erythroid differentiation. Here we investigate the mechanism by which PU.1 interferes with erythroid differentiation. We find that PU.1 interacts directly with GATA-1, a zinc finger transcription factor required for erythroid differentiation. Interaction between PU.1 and GATA-1 requires intact DNA-binding domains in both proteins. PU.1 represses GATA-1-mediated transcriptional activation. Both the DNA binding and transactivation domains of PU.1 are required for repression and both domains are also needed to block terminal differentiation in MEL cells. We also show that ectopic expression of PU.1 in Xenopus embryos is sufficient to block erythropoiesis during normal development. Furthermore, introduction of exogenous GATA-1 in both MEL cells and Xenopus embryos and explants relieves the block to erythroid differentiation imposed by PU.1. Our results indicate that the stoichiometry of directly interacting but opposing transcription factors may be a crucial determinant governing processes of normal differentiation and malignant transformation.