Mathieu Noëlle, Spicuglia Salvatore, Gorbatch Sophie, Cabaud Olivier, Fernex Corinne, Verthuy Christophe, Hempel William M, Hueber Anne-Odile, Ferrier Pierre
Centre d'Immunologie de Marseille-Luminy, INSERM, CNRS, Université de la Méditerranée, 13288 Marseille, France.
J Biol Chem. 2003 May 16;278(20):18101-9. doi: 10.1074/jbc.M212647200. Epub 2003 Mar 14.
To assess the role of the T cell receptor (TCR) beta gene enhancer (Ebeta) in regulating the processing of VDJ recombinase-generated coding ends, we assayed TCRbeta rearrangement of Ebeta-deleted (DeltaEbeta) thymocytes in which cell death is inhibited via expression of a Bcl-2 transgene. Compared with DeltaEbeta, DeltaEbeta Bcl-2 thymocytes show a small accumulation of TCRbeta standard recombination products, including coding ends, that involves the proximal Dbeta-Jbeta and Vbeta14 loci but not the distal 5' Vbeta genes. These effects are detectable in double negative pro-T cells, predominate in double positive pre-T cells, and correlate with regional changes in chromosomal structure during double negative-to-double positive differentiation. We propose that Ebeta, by driving long range nucleoprotein interactions and the control of locus expression and chromatin structure, indirectly contributes to the stabilization of coding ends within the recombination processing complexes. The results also illustrate Ebeta-dependent and -independent changes in chromosomal structure, suggesting distinct modes of regulation of TCRbeta allelic exclusion depending on the position within the locus.
为评估T细胞受体（TCR）β基因增强子（Eβ）在调节VDJ重组酶产生的编码末端加工过程中的作用，我们检测了Eβ缺失（ΔEβ）胸腺细胞的TCRβ重排，其中通过Bcl-2转基因的表达抑制细胞死亡。与ΔEβ相比，ΔEβ Bcl-2胸腺细胞显示出TCRβ标准重组产物的少量积累，包括编码末端，这涉及近端Dβ-Jβ和Vβ14基因座，但不涉及远端5' Vβ基因。这些效应在双阴性前T细胞中可检测到，在双阳性前T细胞中占主导地位，并且与双阴性到双阳性分化过程中染色体结构的区域变化相关。我们提出，Eβ通过驱动长程核蛋白相互作用以及控制基因座表达和染色质结构，间接有助于重组加工复合物内编码末端的稳定化。结果还说明了染色体结构中Eβ依赖性和非依赖性变化，表明取决于基因座内位置的TCRβ等位基因排斥的不同调节模式。
