Jouvin-Marche E, Cazenave P A, Voegtle D, Marche P N
Unité d'Immunochimie Analytique, Centre National de la Recherche Scientifique, Paris, France.
Proc Natl Acad Sci U S A. 1992 Apr 15;89(8):3232-5. doi: 10.1073/pnas.89.8.3232.
The wild-type-derived mouse strain PWK possesses a beta-chain variable region V beta 17a2 allele, which is expressed on mature T cells as part of the T-cell receptor of most mice expressing I-E, whereas V beta 17 T cells are deleted in all I-E+ laboratory mice bearing a V beta 17a1 allele. However, (PWK x CBA/J)F1 progeny and the wild-type-derived mouse strain MAI, which possesses the V beta 17a2 allele, display deletion of V beta 17 T cells. Analysis of (PWK x CBA/J) x PWK and of (PWK x MAI) x PWK backcrosses demonstrates that endogenous mouse mammary tumor virus MTV-6 from CBA/J and a MTV from strain MAI control the clonal deletion of V beta 17a2 as well as V beta 3 T cells. Furthermore, among I-E- progeny of a (MAI x C57BL/6) x C57BL/6 backcross, we observed that mice inheriting MTV of MAI have a reduced level of V beta 17 T cells, suggesting that the clonal deletion of V beta 17a2 T cells can be mediated in the absence of the I-E molecule. The 3' long terminal repeat of MTV MAI was cloned and translation of the open reading frame was compared to those of MTV known to encode superantigens. Comparisons indicate that MTV MAI has significantly diverged from the other MTVs. However, MTV MAI and MTV-6 share a stretch of 11 identical amino acids at the C terminus, which is divergent in MTV reacting with other V beta s. This suggests that this region is involved in determining the specificity toward V beta s and has been selectively conserved through evolution of the Mus species.
源自野生型的小鼠品系PWK拥有β链可变区Vβ17a2等位基因，在大多数表达I-E的小鼠中，该等位基因作为T细胞受体的一部分在成熟T细胞上表达，而在所有携带Vβ17a1等位基因的I-E+实验室小鼠中，Vβ17 T细胞会被删除。然而，（PWK×CBA/J）F1后代以及拥有Vβ17a2等位基因的源自野生型的小鼠品系MAI，均表现出Vβ17 T细胞的缺失。对（PWK×CBA/J）×PWK和（PWK×MAI）×PWK回交后代的分析表明，来自CBA/J的内源性小鼠乳腺肿瘤病毒MTV-6和来自MAI品系的一种MTV控制着Vβ17a2以及Vβ3 T细胞的克隆性删除。此外，在（MAI×C57BL/6）×C57BL/6回交的I-E-后代中，我们观察到继承了MAI的MTV的小鼠Vβ17 T细胞水平降低，这表明在没有I-E分子的情况下，Vβ17a2 T细胞的克隆性删除也可被介导。克隆了MTV MAI的3'长末端重复序列，并将开放阅读框的翻译与已知编码超抗原的MTV的翻译进行了比较。比较表明，MTV MAI与其他MTV有显著差异。然而，MTV MAI和MTV-6在C末端共享一段11个相同的氨基酸，这在与其他Vβ反应的MTV中是不同的。这表明该区域参与决定对Vβ的特异性，并且在小家鼠物种的进化过程中被选择性地保留了下来。
