Hendrickson E A, Schlissel M S, Weaver D T
Division of Tumor Immunology, Dana-Farber Cancer Institute, Boston, Massachusetts.
Mol Cell Biol. 1990 Oct;10(10):5397-407. doi: 10.1128/mcb.10.10.5397-5407.1990.
Homozygous mutation at the scid locus in the mouse results in the aberrant rearrangement of immunoglobulin and T-cell receptor gene segments. We introduced a retroviral vector containing an inversional immunoglobulin rearrangement cassette into scid pre-B cells. Most rearrangements were accompanied by large deletions, consistent with previously characterized effects of the scid mutation. However, two cell clones were identified which contained perfect reciprocal fragments and wild-type coding joints, documenting, on a molecular level, the ability of scid pre-B cells to generate functional protein-coding domains. Subsequent rearrangement of the DGR cassette in one of these clones was accompanied by a deletion, suggesting that this cell clone had not reverted the scid mutation. Indeed, induced rearrangement of the endogenous kappa loci in these two cell clones resulted in a mixture of scid and wild-type V-J kappa joints, as assayed by a polymerase chain reaction and DNA sequencing. In addition, three immunoglobulin mu- scid pre-B cell lines showed both scid and wild-type V-J kappa joins. These experiments strongly suggest that the V(D)J recombinase activity in scid lymphoid cells is diminished but not absent, consistent with the known leakiness of the scid mutation.
小鼠scid基因座的纯合突变导致免疫球蛋白和T细胞受体基因片段的异常重排。我们将一个含有倒位免疫球蛋白重排盒的逆转录病毒载体导入scid前B细胞。大多数重排都伴随着大片段缺失，这与之前所描述的scid突变的效应一致。然而，我们鉴定出两个细胞克隆，它们包含完美的相互片段和野生型编码接头，在分子水平上证明了scid前B细胞产生功能性蛋白质编码结构域的能力。其中一个克隆中DGR盒的后续重排伴随着缺失，这表明该细胞克隆并未恢复scid突变。实际上，通过聚合酶链反应和DNA测序检测发现，这两个细胞克隆中内源性κ基因座的诱导重排导致了scid和野生型V-Jκ接头的混合。此外，三个免疫球蛋白μscid前B细胞系同时显示出scid和野生型V-Jκ接头。这些实验有力地表明，scid淋巴细胞中的V(D)J重组酶活性降低但并非完全缺失，这与已知的scid突变的渗漏性一致。
