GATA-2/estrogen receptor chimera regulates cytokine-dependent growth of hematopoietic cells through accumulation of p21WAF1 and p27Kip1 proteins
GATA-2/estrogen receptor chimera regulates cytokine-dependent growth of hematopoietic cells through accumulation of p21WAF1 and p27Kip1 proteins
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DOI：
10.1182/blood-2002-04-1177
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发表时间：
2002-11-15
期刊：
影响因子：
20.3
通讯作者：
Kanakura, Y
中科院分区：
文献类型：
--
作者：
Ezoe, S;Matsumura, I;Kanakura, Y
加塔-2被认为是造血干细胞（HSC）的发育、维持和功能所必需的。然而，也报道了加塔-2抑制HSC的生长。为了检测加塔-2在造血细胞生长中的作用，我们将雌二醇诱导型加塔-2（加塔-2/雌激素受体[ER]）导入白细胞介素3（IL-3）依赖性细胞系Ba/F3、32 D和FDC-P1。雌二醇诱导的加塔-2抑制c-myc mRNA的表达和抑制IL-3依赖的生长在这些克隆。关于该机制，发现加塔-2抑制p21（WAF 1）和p27（Kip 1）的泛素/蛋白酶体依赖性降解，并通过抑制Skp 2和Cul 1的表达来诱导它们的积累，Skp 2和Cul 1都是p21（WAF 1）和p27（Kip 1）的泛素连接酶的组分。c-myc的过表达恢复了Skp 2和Cul 1 mRNA的表达，减少了p21（WAF 1）和p27（Kip 1）蛋白的含量，并取消了加塔-2诱导的生长抑制，表明c-myc表达下调可能是加塔-2诱导的生长抑制的主要原因。接着，我们将含有加塔-2/ER的逆转录病毒转导入小鼠骨髓单个核细胞（MNCs）和干/祖（Sca-1（+）Lin（-））细胞。加塔-2/ER抑制了MNCs和Sca-1（+）Lin（-）细胞的约70%的精氨酸依赖性生长，这也伴随着c-myc、Skp 2和Cull mRNA表达的减少以及p21（WAF 1）和p27（Kip 1）蛋白的积累。此外，发现通过细胞因子刺激促进进入细胞周期的造血干/祖细胞中加塔-2蛋白的量下降。这些结果表明，加塔-2可以调节p21（WAF 1）和p27（Kip 1）的表达水平，从而有助于造血干/祖细胞的静止。
GATA-2 is considered to be essential for the development, maintenance, and function of hematopoietic stem cells (HSCs). However, it was also reported that GATA-2 Inhibits the growth of HSCs. To examine the role of GATA-2 in the growth of hematopoietic cells, we introduced an estradiol-inducible form of GATA-2 (GATA-2/estrogen receptor [ER]) into interleukin 3 (IL-3)-dependent cell lines, Ba/F3, 32D, and FDC-P1. Estradiol-induced GATA-2 suppressed c-myc mRNA expression and inhibited IL-3-dependent growth in these clones. As for this mechanism, GATA-2 was found to inhibit ubiquitin/proteasome-dependent degradation of p21(WAF1) and p27(Kip1) and to induce their accumulation by repressing the expression of Skp2 and Cul1, both of which are components of the ubiquitin ligase for p21(WAF1) and p27(Kip1). Overexpression of c-myc restored the expression of Skp2 and Cul1 mRNA, reduced the amounts of p21(WAF1) and p27(Kip1) proteins, and canceled GATA-2-induced growth suppression, suggesting that down-regulation of c-myc expression may be primarily responsible for GATA-2-induced growth suppression. Next, we transduced retrovirus containing GATA-2/ER into murine bone marrow mononuclear cells (MNCs) and stem/progenitor (Sca-1(+)Lin(-)) cells. GATA-2/ER suppressed cytokine-dependent growth of MNCs and Sca-1(+)Lin(-) cells by about 70%, which was also accompanied by the reduced expression of c-myc, Skp2, and Cull mRNA and the accumulation of p21(WAF1) and p27(Kip1) proteins. In addition, the amount of GATA-2 protein was found to decline in hematopoietic stem/progenitor cells that were promoted to enter cell cycle by the stimulation with cytokines. These results suggest that GATA-2 may regulate expression levels of p21(WAF1) and p27(Kip1), thereby contributing to the quiescence of hematopoietic stem/progenitor cells.