PU.1 inhibits GATA-1 function and erythroid differentiation by blocking GATA-1 DNA binding.
PU.1 inhibits GATA-1 function and erythroid differentiation by blocking GATA-1 DNA binding.
复制标题
DOI：
10.1182/blood.v96.8.2641
复制
发表时间：
2000-10
期刊：
影响因子：
20.3
通讯作者：
Pu Zhang;Xiaobo Zhang;Atsushi Iwama;Channing Yu;K. Smith;B. Mueller;Salaija Narravula;B. Torbett-B.-To
中科院分区：
文献类型：
--
作者：
Pu Zhang;Xiaobo Zhang;Atsushi Iwama;Channing Yu;K. Smith;B. Mueller;Salaija Narravula;B. Torbett-B.-To
谱系特异性转录因子GATA-1和PU.1可以相互作用以抑制彼此的功能，但PU.1抑制GATA-1功能的机制尚未阐明。PU1的N端和C端都能与GATA-1的C端锌指发生物理作用。研究表明，抑制GATA-1功能需要的是PU.1的N末端，而不是C末端。在K562红白血病细胞中诱导PU1过表达可阻断氯化血红素诱导的红系分化。在这个系统中，PU.1不影响GATA-1信使RNA、蛋白质的表达，也不影响核定位。然而，GATA-1的DNA结合量急剧下降。通过对纯化蛋白的凝胶迁移率改变分析，证明PU.1的N端70个氨基酸可以特异性地阻断GATA-1的DNA结合。此外，PU.1在G1ER细胞系中也有类似的作用，在G1ER细胞系中，GATA-1缺失的红系细胞系G1E已经被转导了GATA-1-雌激素受体融合基因，该融合基因直接依赖于GATA-1融合蛋白的诱导来影响红系成熟。与体外结合实验一致，PU.1的过表达阻断了GATA-1融合蛋白的DNA结合以及GATA-1介导的G1ER细胞的红系分化。这些结果证明了一种新的机制，即一个谱系特异的转录因子的功能被另一个谱系限制因子通过直接的蛋白质-蛋白质相互作用来抑制。这些发现有助于理解蛋白质-蛋白质相互作用如何参与造血分化和白血病的发生。(血。2000；96：2641-2648)
The lineage-specific transcription factors GATA-1 and PU.1 can physically interact to inhibit each other's function, but the mechanism of repression of GATA-1 function by PU.1 has not been elucidated. Both the N terminus and the C terminus of PU.1 can physically interact with the C-terminal zinc finger of GATA-1. It is demonstrated that the PU.1 N terminus, but not the C terminus, is required for inhibiting GATA-1 function. Induced overexpression of PU.1 in K562 erythroleukemia cells blocks hemin-induced erythroid differentiation. In this system, PU.1 does not affect the expression of GATA-1 messenger RNA, protein, or nuclear localization. However, GATA-1 DNA binding decreases dramatically. By means of electrophoretic mobility shift assays with purified proteins, it is demonstrated that the N-terminal 70 amino acids of PU.1 can specifically block GATA-1 DNA binding. In addition, PU.1 had a similar effect in the G1ER cell line, in which the GATA-1 null erythroid cell line G1E has been transduced with a GATA-1-estrogen receptor fusion gene, which is directly dependent on induction of the GATA-1 fusion protein to effect erythroid maturation. Consistent with in vitro binding assays, overexpression of PU.1 blocked DNA binding of the GATA-1 fusion protein as well as GATA-1-mediated erythroid differentiation of these G1ER cells. These results demonstrate a novel mechanism by which function of a lineage-specific transcription factor is inhibited by another lineage-restricted factor through direct protein-protein interactions. These findings contribute to understanding how protein-protein interactions participate in hematopoietic differentiation and leukemogenesis. (Blood. 2000;96:2641-2648)