Ishikawa H, Shinkai Y, Yagita H, Yue C C, Henkart P A, Sawada S, Young H A, Reynolds C W, Okumura K
Department of Immunology, Juntendo University, School of Medicine, Tokyo, Japan.
J Immunol. 1989 Nov 1;143(9):3069-73.
Rat cytolysin is one of the cytolytic factors present in the cytoplasmic granules of rat NK-like cytolytic cells and purified cytolysin exhibits an apparent Mr or 70 kDa. Cytolysis produced by cytolysin occurs in the presence of Ca2+ and is accompanied by the formation of membrane lesions of 160 A diameter. We have isolated a cDNA encoding rat cytolysin from the cDNA library of a rat large granular lymphocyte (LGL) cell line, by hybridization of the rat library with a cDNA probe for mouse perforin. The amino acid sequence deduced from the nucleotide sequence of the isolated cDNA insert indicates that the mature cytolysin protein consist of 534 amino acids with a leader peptide of 20 amino acids. The protein contains two functionally important domains: the first domain is believed to contain the transmembrane channel and the second domain consists of an epidermal growth factor-type "class B" cysteine-rich region. A comparison with mouse perforin indicates that the two genes are very similar (89.9% nucleotide and 84.9% amino acid identity). Northern blot hybridization analysis indicates that cytolysin mRNA is expressed in rat lymphocytes (lymphokine-activated killer cells and LGL cells) and LGL cell lines.
大鼠溶细胞素是存在于大鼠自然杀伤样溶细胞细胞胞质颗粒中的溶细胞因子之一，纯化后的溶细胞素表现出约70 kDa的表观分子量。溶细胞素产生的细胞溶解作用在Ca2+存在的情况下发生，并伴随着直径为160 Å的膜损伤的形成。我们通过用小鼠穿孔素的cDNA探针与大鼠文库杂交，从大鼠大颗粒淋巴细胞（LGL）细胞系的cDNA文库中分离出了编码大鼠溶细胞素的cDNA。从分离的cDNA插入片段的核苷酸序列推导的氨基酸序列表明，成熟的溶细胞素蛋白由534个氨基酸组成，带有一个20个氨基酸的前导肽。该蛋白包含两个功能上重要的结构域：第一个结构域被认为包含跨膜通道，第二个结构域由表皮生长因子型“B类”富含半胱氨酸区域组成。与小鼠穿孔素的比较表明，这两个基因非常相似（核苷酸同一性为89.9%，氨基酸同一性为84.9%）。Northern印迹杂交分析表明，溶细胞素mRNA在大鼠淋巴细胞（淋巴因子激活的杀伤细胞和LGL细胞）以及LGL细胞系中表达。
