Institute of Bioscience, Department of Bioscience and Biotechnology, Sejong University, Seoul, Republic of Korea.
Oncol Rep. 2010 May;23(5):1463-8. doi: 10.3892/or_00000785.
Previously, we generated thymic lymphoma cell lines from EbetaR/Rp53-/- (EP) double mutant mice where the T cell receptor (TCR) beta enhancer (Ebeta) was deleted, and the p53 gene was inactivated. Here, we characterized the EP cell lines to study the roles of the Ebeta and p53 on TCRbeta rearrangements during lymphomagenesis. Recombination activation genes (RAGs) were expressed, while the TCRbeta chain was not expressed in the EP cell lines. Dbeta-Jbeta rearrangements were not detected at all, and Dbeta1 and Dbeta2 cleavages were also not detected in the EP cell lines. However, Jbeta cleavages suppressed in Ebeta mutant thymocytes were readily detected in the EP cell lines. The Jbeta cleavages appeared to be uncoupled, aberrant, RAG-dependent and Ebeta-independent and were not detected in a p53 or Ebeta single mutant background, suggesting that the Jbeta cleavages are selected in the Ebeta and p53 double mutant background. Sequence analysis showed that the cleavage occurred in the cryptic recombination signal sequences (RSSs) present throughout Jbeta gene segments. The results implicate that the uncoupled and aberrant V(D)J cleavages may contribute to double-strand break-mediated genome instability during lymphomagenesis in EP mice.
先前，我们从 EbetaR/Rp53-/-（EP）双突变小鼠中生成了胸腺癌细胞系，该小鼠中 T 细胞受体（TCR）β增强子（Ebeta）缺失，p53 基因失活。在这里，我们对 EP 细胞系进行了特征描述，以研究 Ebeta 和 p53 在胸腺癌发生过程中对 TCRβ重排的作用。重组激活基因（RAG）表达，但 EP 细胞系中不表达 TCRβ链。完全未检测到 Dbeta-Jbeta 重排，并且在 EP 细胞系中也未检测到 Dbeta1 和 Dbeta2 切割。然而，在 Ebeta 突变胸腺细胞中受到抑制的 Jbeta 切割在 EP 细胞系中很容易被检测到。Jbeta 切割似乎是解偶联的、异常的、RAG 依赖性的且不依赖于 Ebeta，并且在 p53 或 Ebeta 单突变背景中未检测到，这表明 Jbeta 切割是在 Ebeta 和 p53 双突变背景中选择的。序列分析表明，切割发生在 Jbeta 基因片段中存在的隐蔽重组信号序列（RSS）中。结果表明，解偶联和异常的 V(D)J 切割可能导致 EP 小鼠胸腺癌发生过程中的双链断裂介导的基因组不稳定性。
