Godbout R, Packer M, Bie W
Department of Oncology, Cross Cancer Institute and University of Alberta, 11560 University Ave., Edmonton, Alberta T6G1Z2, Canada.
J Biol Chem. 1998 Aug 14;273(33):21161-8. doi: 10.1074/jbc.273.33.21161.
The DEAD box gene, DDX1, is a putative RNA helicase that is co-amplified with MYCN in a subset of retinoblastoma (RB) and neuroblastoma (NB) tumors and cell lines. Although gene amplification usually involves hundreds to thousands of kilobase pairs of DNA, a number of studies suggest that co-amplified genes are only overexpressed if they provide a selective advantage to the cells in which they are amplified. Here, we further characterize DDX1 by identifying its putative transcription and translation initiation sites. We analyze DDX1 protein levels in MYCN/DDX1-amplified NB and RB cell lines using polyclonal antibodies specific to DDX1 and show that there is a good correlation with DDX1 gene copy number, DDX1 transcript levels, and DDX1 protein levels in all cell lines studied. DDX1 protein is found in both the nucleus and cytoplasm of DDX1-amplified lines but is localized primarily to the nucleus of nonamplified cells. Our results indicate that DDX1 may be involved in either the formation or progression of a subset of NB and RB tumors and suggest that DDX1 normally plays a role in the metabolism of RNAs located in the nucleus of the cell.
DEAD盒基因DDX1是一种推定的RNA解旋酶，在一部分视网膜母细胞瘤（RB）和神经母细胞瘤（NB）肿瘤及细胞系中与MYCN共同扩增。尽管基因扩增通常涉及数百到数千千碱基对的DNA，但多项研究表明，共同扩增的基因只有在为其扩增所在的细胞提供选择优势时才会过度表达。在此，我们通过鉴定其推定的转录和翻译起始位点来进一步表征DDX1。我们使用针对DDX1的多克隆抗体分析了MYCN/DDX1扩增的NB和RB细胞系中的DDX1蛋白水平，结果表明，在所有研究的细胞系中，DDX1基因拷贝数、DDX1转录水平和DDX1蛋白水平之间存在良好的相关性。在DDX1扩增的细胞系的细胞核和细胞质中均发现了DDX1蛋白，但在未扩增细胞中主要定位于细胞核。我们的结果表明，DDX1可能参与了一部分NB和RB肿瘤的形成或进展，并提示DDX1通常在位于细胞核内的RNA代谢中发挥作用。
