AML1、AML1-ETO对nucb2基因转录调控活性的影响

Influence of AML1 and AML1-ETO on Transcriptional Regulation of nucb2 Gene

本研究旨在探讨造血特异转录因子AML1及M2b型急性髓系白血病(AML-M2b)累及的异常融合蛋白AML1-ETO对凋亡相关基因nucb2(nucleobindin-2)启动子转录活性的影响,探索AML1-ETO对AML-M2b型白血病的分子致病机制。利用实时RT-PCR方法在AML1-ETO诱导型白血病细胞株中研究AML1-ETO在转录水平对于nucb2的调控情况;利用ChIP-qPCR方法在AML1-ETO阳性白血病细胞株中研究AML1、AML1-ETO与nucb2基因启动子之间直接的体内相互作用情况;采用双荧光素酶报告基因检测方法,研究AML1、AML1-ETO对nucb2启动子转录活性的调节作用。结果表明:AML1-ETO的表达与nucb2的表达呈负相关;nucb2可能是AML1、AML1-ETO的靶基因;AML1、AML1-ETO皆对nucb2启动子具有转录抑制作用,且AML1-ETO对nucb2抑制更强。结论:nucb2是AML1、AML1-ETO的直接靶基因,AML1、AML1-ETO通过抑制nucb2启动子的活性对其进行转录调控。

This study was purposed to investigate the effect of AML1 -ETO fusion protein resulted from hematopoietic transcription factor （ AML1 ） and acute rnyeloid leukemia M2b （ AML-M2b ） on transcription activity of nucleobindin 2 （nucb2） promoter, and to explore the role of AML1-ETO in molecular pathogenesis of AML-M2b. The real-time RT- PCR was used to study the regulation of AML1-ETO on nucb2 at transcription level in AML1-ETO inducible leukemia cell line, the chromatin immunoprecipitation （CHIP）-based qPCR was used to investigate the direct in vivo interaction between the AML1, AML1-ETO and nucb2 promoter in AML1-ETO positive leukemia cell line, the luciferase report gene assay was used to detect the regulation of AML1, AML1-ETO on the transcription activity of nucb2 promoter. The results showed that the expression level of nucb2 was reduced with the increase of AML1-ETO. The promoter of nucb2 could be bound by both AML1 and AML1-ETO. The promoter of nucb2 was trans-repressed by AML1 and AML1-ETO respectively. It is concluded that the nucb2 is the direct target gene of AML1 and AML1-ETO, the transcription regulation of AML1, AML1-ETO on nucb2 is carried out via repressing its promoter activity.