MOLECULAR DEFINITION AND SEQUENCE MOTIFS OF THE 52-KD COMPONENT OF HUMAN SS-A/RO AUTOANTIGEN
MOLECULAR DEFINITION AND SEQUENCE MOTIFS OF THE 52-KD COMPONENT OF HUMAN SS-A/RO AUTOANTIGEN
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DOI：
10.1172/jci115003
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发表时间：
1991-01-01
影响因子：
15.9
通讯作者：
TAN, EM
中科院分区：
文献类型：
--
作者：
CHAN, EKL;HAMEL, JC;TAN, EM
血清 SS-A/Ro 自身抗体常见于干燥综合征、系统性红斑狼疮、新生儿狼疮和亚急性皮肤狼疮患者。 60 和 52 kD 的两种蛋白质已被描述为这些自身抗体的靶标。为了明确定义 52-kD 成分，从人 HepG2 和 MOLT-4 细胞 cDNA 文库中分离出 cDNA 克隆。 cDNA 的身份通过 (a) 从重组蛋白亲和纯化的抗体的特异性，(b) 纯化的重组蛋白与原型 SS-A/Ro 血清在免疫印迹和 ELISA 中的反应性，以及 (c) MOLT-4 细胞 52-kD 蛋白和重组蛋白的二维凝胶共迁移来确定。 1.9 kb cDNA 编码包含 475 个氨基酸的完整 52 kD 蛋白质 (M(r) 54,082)。在 52-kD 蛋白质的氨基末端一半中鉴定出了假定的锌指结构域和亮氨酸拉链基序，暗示其可能与 DNA/RNA 相关。在 52-kD 蛋白和人 ret 转化蛋白以及小鼠 T 细胞基因表达下调蛋白 rpt-1 之间检测到的序列同源性，除了这些蛋白可能构成指蛋白亚家族成员的可能性之外，还可能为 52-5D 蛋白的功能作用提供线索。
Serum SS-A/Ro autoantibodies are commonly found in patients with Sjogren's syndrome, systemic lupus erythematosus, neonatal lupus, and subacute cutaneous lupus. Two proteins of 60 and 52 kD have been described as targets for these autoantibodies. To define the 52-kD component unambiguously, cDNA clones were isolated from human HepG2 and MOLT-4 cell cDNA libraries. The identity of cDNA was established by (a) the specificity of the antibody affinity purified from the recombinant protein, (b) the reactivity of the purified recombinant protein with prototype SS-A/Ro sera in immunoblot and ELISA, and (c) two-dimensional gel comigration of MOLT-4 cell 52-kD protein and the recombinant protein. A 1.9-kb cDNA encoded the complete 52-kD protein containing 475 amino acids (M(r) 54,082). Putative zinc-finger domains and leucine zipper motif were identified in the amino-terminal half of the 52-kD protein, implicating its possible association with DNA/RNA. Sequence homology detected between the 52-kD protein and human ret transforming protein, and mouse T cell gene expression down-regulatory protein rpt-1, may provide leads to the functional role of the 52-5D protein in addition to the possibility that these proteins might constitute members of a subfamily of finger proteins.