Involvement of Notch1 in the development of mouse mammary tumors
Involvement of Notch1 in the development of mouse mammary tumors
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DOI：
10.1038/sj.onc.1202991
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发表时间：
1999-10-28
期刊：
影响因子：
8
通讯作者：
Jolicoeur, P
中科院分区：
文献类型：
--
作者：
Diévart, A;Beaulieu, N;Jolicoeur, P
MMTV/neu转基因（Tg）小鼠在长潜伏期后自发地随机发生乳腺肿瘤，表明c-neu/erbB 2癌基因不足以形成肿瘤。为了鉴定c-neu/erbB 2的协同基因，我们采用前病毒插入突变的方法，对感染小鼠乳腺肿瘤病毒（MMTV）的MMTV/neu Tg小鼠的乳腺肿瘤进行了研究。Notch 1基因被鉴定为MMTV前病毒插入激活的新靶点。在Notch 1重排的肿瘤中，Notch 1基因被MMTV前病毒插入到编码TM结构域的外显子上游而中断。这些插入导致了新的5'截短的类似于7 kb的RNA的过表达，其编码仅含有Notch 1胞外域的280 kDa突变蛋白，N（EC）（mut），这些可能参与肿瘤形成。这些插入的另一个结果是表达截短的3'Notch 1转录本（3.5-4.5 kb）和缺失大部分细胞外序列（Notch 1（内部））的蛋白质（86-110 kDa）。我们发现3'截短的Notch 1（intra）在体外可以转化HC 11小鼠乳腺上皮细胞。缺失分析显示，需要锚定重复序列和结构域1（aa 1751-1821），而信号肽、两个保守的半胱氨酸（C-1652和C-1685）以及OPA和PEST序列是转化所必需的。这些结果表明，N-末端截短的Notch 1（内）蛋白在该系统中表现为癌基因。
The MMTV/neu transgenic (Tg) mice spontaneously develop mammary tumors stochastically after a long latent period, suggesting that the c-neu/erbB2 oncogene is not sufficient for tumor formation. To identify putative collaborator(s) of the c-neu/erbB2, we used the provirus insertional mutagenesis approach with mammary tumors arising in MMTV/neu Tg mice infected with the mouse mammary tumor virus (MMTV), The Notch1 gene was identified as a novel target for MMTV provirus insertional activation. In Notch1-rearranged tumors, the Notch1 gene was interrupted by the MMTV provirus insertion upstream of the exons coding for the TM domain. These insertions led to overexpression of novel 5' truncated similar to 7kb RNA coding for 280 kDa mutant protein harboring only the Notch1 ectodomain, N(EC)(mut), These may be involved in tumor formation. Another consequence of these insertions was the expression of truncated 3' Notch1 transcripts (3.5-4.5 kb) and proteins (86-110 kDa) deleted of most of the extracellular sequences (Notch1(intra)). We found that 3' truncated Notch1(intra) can transform HC11 mouse mammary epithelial cells in vitro. Deletion analysis revealed that the ankyrin-repeats and the domain 1 (aa 1751-1821) are required, while a signal peptide, the two conserved cysteines (C-1652 and C-1685) and the OPA and PEST sequences are dispensable for transformation. These results indicate that the N-terminally truncated Notch1(intra) protein behaves as an oncogene in this system.