Dual Transforming Activities of the FUS (TLS)-ERG Leukemia Fusion Protein Conferred by Two N-Terminal Domains of FUS (TLS)-猫眼课题宝

FUS (TLS) 的两个 N 端结构域赋予 FUS (TLS)-ERG 白血病融合蛋白的双重转化活性

DOI：

发表时间：

1999

期刊：

Molecular and Cellular Biology

影响因子：

5.3

通讯作者：

中科院分区：

生物学2区

文献类型：

作者：

H. Ichikawa;K. Shimizu;Rieko Katsu;M. Ohki

摘要与t(16；21)(p11；q22)急性髓系白血病相关的FUS(TLS)-ERG嵌合蛋白在结构上与尤文肉瘤嵌合转录因子EWS-ERG相似。我们发现FUS-ERG和EWS-ERG均能诱导小鼠成纤维细胞系NIH3T3非贴壁依赖性增殖。然而，只有FUS-ERG能够抑制小鼠髓系前体细胞系L-G向中性粒细胞的分化，并诱导其粒细胞集落刺激因子依赖性生长。我们构建了几个缺失FUS-ERG N-末端FUS区的突变体。缺失氨基酸1~173(外显子1~5)的缺失突变体失去了NIH3T3转化活性，但保留了L G转化活性。另一方面，缺失第174和第265位氨基酸之间区域(外显子6和7)的突变体失去了L-G转化活性，但保留了NIH3T3-转化活性。这些结果表明，FUS的N-末端含有NIH3T3和L-G转换所需的两个独立的功能结构域，我们分别命名为Tr1和Tr2。尽管EWS本质上具有TR2结构域，但所采用的EWS-ERG结构缺乏包含该结构域的EWS序列。由于TR2结构域总是存在于t(16；21)白血病患者的嵌合蛋白中，而不存在于尤文肉瘤患者的嵌合蛋白中，因此似乎只有在白血病发生的潜能中才需要TR2功能。此外，我们确定了三个细胞基因的表达被异位表达的FUS-ERG改变，并发现这些基因是以TR1依赖或TR2依赖的方式调节的。这些结果提示，在白血病发生过程中，FUS-ERG可能通过同时调节两组不同基因的表达来激活两条独立的致癌途径。

ABSTRACT The FUS (TLS)-ERG chimeric protein associated with t(16;21)(p11;q22) acute myeloid leukemia is structurally similar to the Ewing’s sarcoma chimeric transcription factor EWS-ERG. We found that both FUS-ERG and EWS-ERG could induce anchorage-independent proliferation of the mouse fibroblast cell line NIH 3T3. However, only FUS-ERG was able to inhibit the differentiation into neutrophils of a mouse myeloid precursor cell line L-G and induce its granulocyte colony-stimulating factor-dependent growth. We constructed several deletion mutants of FUS-ERG lacking a part of the N-terminal FUS region. A deletion mutant lacking the region between amino acids 1 and 173 (exons 1 to 5) lost the NIH 3T3-transforming activity but retained the L-G-transforming activity. On the other hand, a mutant lacking the region between amino acids 174 and 265 (exons 6 and 7) lost the L-G-transforming activity but retained the NIH 3T3-transforming activity. These results indicate that the N-terminal region of FUS contains two independent functional domains required for the NIH 3T3 and L-G transformation, which we named TR1 and TR2, respectively. Although EWS intrinsically possessed the TR2 domain, the EWS-ERG construct employed lacked the EWS sequence containing this domain. Since the TR2 domain is always found in chimeric proteins identified from t(16;21) leukemia patients but not in chimeric proteins from Ewing’s sarcoma patients, it seems that the TR2 function is required only for the leukemogenic potential. In addition, we identified three cellular genes whose expression was altered by ectopic expression of FUS-ERG and found that these are regulated in either a TR1-dependent or a TR2-dependent manner. These results suggest that FUS-ERG may activate two independent oncogenic pathways during the leukemogenic process by modulating the expression of two different groups of genes simultaneously.