Yamamoto K, Koch N, Steinmetz M, Hämmerling G J
J Immunol. 1985 May;134(5):3461-7.
Murine immune response region-encoded Ia antigens are associated not only with invariant (Ii) chain but also with several other polypeptides, most notably a 41K protein. The present report demonstrates a striking similarity between Ii and 41K. These polypeptides were found to be serologically cross-reactive, and they also display a similar peptide composition on partial enzymatic digestion. Both polypeptides are derived from distinct unglycosylated precursors, as demonstrated by tunicamycin treatment and cellfree translation. Hybrid selection of mRNA, as well as Northern blotting with an Ii cDNA, shows the presence of two mRNA coding for the Ii chain and the 41K protein. Rat fibroblasts transfected with a mouse genomic Ii clone synthesize both the murine Ii chain and the 41K protein. These observations demonstrate that a single Ii gene encodes two distinct but closely related proteins.
小鼠免疫反应区编码的Ia抗原不仅与恒定链（Ii）相关，还与其他几种多肽相关，最显著的是一种41K蛋白。本报告证明了Ii和41K之间存在惊人的相似性。发现这些多肽在血清学上具有交叉反应性，并且在部分酶解时也显示出相似的肽组成。两种多肽均来自不同的未糖基化前体，衣霉素处理和无细胞翻译证明了这一点。mRNA的杂交选择以及用Ii cDNA进行的Northern印迹显示存在两种编码Ii链和41K蛋白的mRNA。用小鼠基因组Ii克隆转染的大鼠成纤维细胞合成小鼠Ii链和41K蛋白。这些观察结果表明，单个Ii基因编码两种不同但密切相关的蛋白质。
