Yabe T, McSherry C, Bach F H, Houchins J P
Department of Laboratory Medicine, University of Minnesota, Minneapolis 55455.
J Exp Med. 1990 Oct 1;172(4):1159-63. doi: 10.1084/jem.172.4.1159.
We have isolated a series of cross-hybridizing cDNA clones, as a group designated as NKG5, from a human natural killer (NK) cell clone cDNA library. These clones show a high degree of homology with a previously described gene, 519, which was thought to be T cell specific. A comparison of the full-length cDNA sequence of NKG5 and the published sequence of 519 shows that NKG5 lacks a 242-base segment that is found in 519 and that this deletion leads to the use of a different putative translational start codon. Unlike 519, the predicted NKG5 polypeptide has an NH2-terminal sequence that is strongly hydrophobic, characteristic of a signal peptide, and lacks any additional hydrophobic regions in the remainder of the peptide, suggesting that NKG5 encodes a secreted protein. Both NKG5 and 519 are expressed in NK and T cells but not in a variety of other hematopoietic cell lines. NKG5 is an abundant transcript and its level of expression is about 40 times that of 519 in NK and T cells. Southern blot and DNA sequence analyses suggest that NKG5 and 519 mRNAs are transcripts from a single gene that has allelic polymorphism.
我们从一个人类自然杀伤（NK）细胞克隆cDNA文库中分离出了一系列相互交叉杂交的cDNA克隆，将其作为一个组命名为NKG5。这些克隆与先前描述的基因519具有高度同源性，519被认为是T细胞特异性的。NKG5全长cDNA序列与已发表的519序列的比较表明，NKG5缺少519中存在的一个242个碱基的片段，并且这种缺失导致使用了不同的假定翻译起始密码子。与519不同，预测的NKG5多肽具有一个NH2末端序列，该序列具有很强的疏水性，是信号肽的特征，并且在肽的其余部分没有任何其他疏水区域，这表明NKG5编码一种分泌蛋白。NKG5和519在NK细胞和T细胞中均有表达，但在多种其他造血细胞系中不表达。NKG5是一种丰富的转录本，其在NK细胞和T细胞中的表达水平约为519的40倍。Southern印迹和DNA序列分析表明，NKG5和519 mRNA是来自具有等位基因多态性的单个基因的转录本。
