de Oca Luna R M, Tabor A D, Eberspaecher H, Hulboy D L, Worth L L, Colman M S, Finlay C A, Lozano G
Department of Molecular Genetics, University of Texas, M. D. Anderson Cancer Center, Houston, Texas, 77030, USA.
Genomics. 1996 May 1;33(3):352-7. doi: 10.1006/geno.1996.0210.
The mdm2 gene encodes a zinc finger protein that negatively regulates p53 function by binding and masking the p53 transcriptional activation domain. Two different promoters control expression of mdm2, one of which is also transactivated by p53. We cloned and characterized the mdm2 gene from a murine 129 library. It contained at least 12 exons and spanned approximately 25 kb of DNA. Sequencing of the mdm2 gene revealed three nucleotide differences that resulted in amino acid substitutions in the previously published mdm2 sequence. Sequencing of normal BalbC/J DNA and the original cosmid clone isolated from the 3T3DM cell line revealed that they are identical, suggesting that the published sequence is in error at these three positions. In addition, we analyzed the expression pattern of mdm2 and found ubiquitous low-level expression throughout embryo development and in adult tissues. Analysis of mRNA from numerous tissues for several mdm2 spliced variants that had been identified in the transformed 3T3DM cell line revealed that these variants could not be detected in the developing embryo or in adult tissues.
mdm2基因编码一种锌指蛋白，该蛋白通过结合并掩盖p53转录激活域来负向调节p53功能。两个不同的启动子控制mdm2的表达，其中一个启动子也由p53反式激活。我们从鼠129文库中克隆并鉴定了mdm2基因。它包含至少12个外显子，跨越约25kb的DNA。mdm2基因测序揭示了三个核苷酸差异，这些差异导致了先前发表的mdm2序列中的氨基酸替换。对正常BalbC/J DNA和从3T3DM细胞系分离的原始黏粒克隆进行测序，结果表明它们是相同的，这表明已发表的序列在这三个位置上存在错误。此外，我们分析了mdm2的表达模式，发现在整个胚胎发育过程以及成年组织中均存在普遍的低水平表达。对来自众多组织的mRNA进行分析，以检测在转化的3T3DM细胞系中已鉴定出的几种mdm2剪接变体，结果显示在发育中的胚胎或成年组织中无法检测到这些变体。
