Kallenbach S, Brinkmann T, Rougeon F
Unité de Génétique et Biochimie du Développement, CNRS URA 361, Institut Pasteur, Paris, France.
Int Immunol. 1993 Feb;5(2):231-2. doi: 10.1093/intimm/5.2.231.
Recombination activating genes Rag-1 and Rag-2 were isolated on the basis of their ability to confer V(D)J recombination activity when co-expressed in fibroblasts. The mode of action of the confer V(D)J recombination activity when co-expressed in fibroblasts. The mode of action of the products of these genes is not known. Based on sequence comparison data, it was suggested that Rag-1 protein could act like a topoisomerase and that tyrosine in position 998 could be the active site tyrosine. We tested this hypothesis by introducing a point mutation on the Rag-1 cDNA, transforming the tyrosine codon into a phenylalanine codon. We show that the mutation has no effect on site specific recombination implying that Tyr-998 is not essential for the recombination reaction.
重组激活基因Rag-1和Rag-2是根据它们在成纤维细胞中共表达时赋予V(D)J重组活性的能力而分离出来的。这些基因在成纤维细胞中共表达时赋予V(D)J重组活性的作用模式。这些基因产物的作用模式尚不清楚。基于序列比较数据，有人提出Rag-1蛋白可能像拓扑异构酶一样起作用，并且998位的酪氨酸可能是活性位点酪氨酸。我们通过在Rag-1 cDNA上引入点突变，将酪氨酸密码子转化为苯丙氨酸密码子来检验这一假设。我们表明该突变对位点特异性重组没有影响，这意味着Tyr-998对重组反应不是必需的。
