Schwab Susan R, Li Katy C, Kang Chulho, Shastri Nilabh
Division of Immunology, Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3200, USA.
Science. 2003 Sep 5;301(5638):1367-71. doi: 10.1126/science.1085650.
Major histocompatibility complex (MHC) class I molecules display tens of thousands of peptides on the cell surface, derived from virtually all endogenous proteins, for inspection by cytotoxic T cells (CTLs). We show that, in normal mouse cells, MHC I molecules present a peptide encoded in the 3' "untranslated" region. Despite its rarity, the peptide elicits CTL responses and induces self-tolerance, establishing that immune surveillance extends well beyond conventional polypeptides. Furthermore, translation of this cryptic peptide occurs by a previously unknown mechanism that decodes the CUG initiation codon as leucine rather than the canonical methionine.
主要组织相容性复合体（MHC）I类分子在细胞表面展示数以万计的肽段，这些肽段几乎来源于所有内源性蛋白质，以供细胞毒性T细胞（CTL）检查。我们发现，在正常小鼠细胞中，MHC I类分子呈现一种由3' “非翻译” 区域编码的肽段。尽管这种肽段很罕见，但它能引发CTL反应并诱导自身耐受，这表明免疫监视远远超出了传统多肽的范围。此外，这种隐秘肽段的翻译是通过一种以前未知的机制进行的，该机制将CUG起始密码子解码为亮氨酸而非标准的甲硫氨酸。
