Granulocytic differentiation of normal hematopoietic precursor cells induced by transcription factor PU.1 correlates with negative regulation of the c-myb promoter
Granulocytic differentiation of normal hematopoietic precursor cells induced by transcription factor PU.1 correlates with negative regulation of the c-myb promoter
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DOI：
10.1182/blood.v90.5.1828
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发表时间：
1997-09-01
期刊：
影响因子：
20.3
通讯作者：
Calabretta, B
中科院分区：
文献类型：
--
作者：
Bellon, T;Perrotti, D;Calabretta, B
许多转录因子允许造血细胞响应谱系和阶段特异性细胞因子和/或充当其效应子。转录因子PU.1和c-Myb是造血所必需的，最有可能在分化的不同阶段起作用，但共享一组共同的靶基因。为了确定PU.1和c-Myb是否在功能上相互关联，用携带PU.1 cDNA的逆转录病毒感染小鼠骨髓（BM）细胞和32 Dc 13小鼠骨髓前体细胞，并分别评估骨髓集落形成和粒细胞分化。与未感染的正常BM细胞或空病毒感染的细胞相比，表达PU.1的造血前体细胞形成的白细胞介素-3（IL-3）和粒细胞集落刺激因子（G-CSF）刺激的集落数量增加。此外，组成型表达PU.1的32 Dc 13细胞的粒细胞分化加速，如形态学和分化标记物的表达所示。通过表达反义c-myb构建体下调c-myb蛋白水平也与32 Dc 13粒细胞分化的更快动力学相关。c-myb基因5'侧翼区的序列分析揭示了在+16至+21位的共有PU盒，其能够在电泳迁移率变动分析中与细菌合成的PU. 1蛋白或来自分化的32 Dc 13细胞的全细胞提取物特异性相互作用。在不同细胞系的共转染试验中，PU.1的瞬时表达导致由c-myb启动子的不同片段驱动的氯霉素乙酰转移酶活性的抑制。此外，这种作用依赖于完整的PU hox。因此，PU. 1增强终末髓样分化的能力似乎涉及c-myb表达的下调，这是造血前体细胞分化过程中的一个重要步骤。(C)1997年，美国血液学会。
Numerous transcription factors allow hematopoietic cells to respond to lineage-and stage-specific cytokines and/or to act as their effecters. The transcription factors PU.1 and c-Myb are essential for hematopoiesis, most likely acting at distinct stages of differentiation, but sharing a common set of target genes. To determine whether PU.1 and c-Myb are functionally interrelated, murine bone marrow (BM) cells and 32Dc13 murine myeloid precursor cells were infected with a retrovirus carrying a PU.1 cDNA and assessed for myeloid colony formation and for granulocytic differentiation, respectively. Compared with noninfected normal BM cells or to cells infected with an empty virus, hematopoietic precursor cells expressing PU.1 formed an increased number of interleukin-3 [IL-3) and granulocyte colony-stimulating factor (G-CSF)-stimulated colonies. Moreover, granulocytic differentiation of 32Dc13 cells constitutively expressing PU.1 was accelerated, as indicated by morphology and by expression of differentiation markers. Downregulation of c-Myb protein levels by expression of an antisense c-myb construct was also associated with a faster kinetics of 32Dc13 granulocytic differentiation. Sequence analysis of the 5' flanking region of the c-myb gene revealed a consensus PU box at position +16 to +21 able to specifically interact in electrophoretic mobility shift assays with either bacterially synthesized PU.1 protein or whole cell extracts from differentiated 32Dc13 cells. Transient expression of PU.1 in cotransfection assays in different cell lines resulted in inhibition of chloramphenicol acetyl transferase activity driven by different segments of the c-myb promoter. Moreover, such an effect was dependent on an intact PU hox, Thus, the ability of PU.1 to potentiate terminal myeloid differentiation appears to involve downregulation of c-myb expression, an essential step during differentiation of hematopoietic precursor cells. (C) 1997 by The American Society of Hematology.