McCauliffe D P, Zappi E, Lieu T S, Michalak M, Sontheimer R D, Capra J D
Department of Dermatology, University of Texas Southwestern Medical Center, Dallas 75235.
J Clin Invest. 1990 Jul;86(1):332-5. doi: 10.1172/JCI114704.
The Ro/SS-A (Ro) autoantigens consist of at least four immunologically distinct proteins which are recognized by autoantibodies typically found in sera from patients with primary Sjogren's syndrome and in subsets of patients with lupus erythematosus. We recently isolated a 1.9-kb human cDNA clone which encodes one of these Ro autoantigens. Synthetic oligonucleotides corresponding to the human Ro sequence were used to amplify the homologous gene from a murine B cell cDNA library using the polymerase chain reaction. The mouse cDNA-encoded amino acid sequence was found to be 94% homologous to the human Ro sequence and is 100% homologous to murine calreticulin, a high affinity calcium-binding protein which resides in the endoplasmic and sarcoplasmic reticulum. The amino acid sequence of rabbit calreticulin is 92% homologous to both murine calreticulin and human Ro. Onchocerca volvulus and Drosophila melanogaster also have molecules that are highly homologous to human Ro. In addition, human Ro has a molecular mass, isoelectric point, and significant amino acid sequence similar to the Aplysia californica snail neuronal protein 407. These homologies suggest that this Ro protein has a very basic cellular function(s) which may in part involve calcium binding.
Ro/SS-A（Ro）自身抗原至少由四种免疫上不同的蛋白质组成，这些蛋白质可被自身抗体识别，这些自身抗体通常存在于原发性干燥综合征患者以及红斑狼疮患者亚组的血清中。我们最近分离出一个1.9kb的人类cDNA克隆，它编码这些Ro自身抗原之一。使用聚合酶链反应，对应于人类Ro序列的合成寡核苷酸被用于从鼠B细胞cDNA文库中扩增同源基因。发现小鼠cDNA编码的氨基酸序列与人类Ro序列有94%的同源性，并且与鼠钙网蛋白100%同源，鼠钙网蛋白是一种高亲和力的钙结合蛋白，存在于内质网和肌浆网中。兔钙网蛋白的氨基酸序列与鼠钙网蛋白和人类Ro均有92%的同源性。盘尾丝虫和黑腹果蝇也有与人类Ro高度同源的分子。此外，人类Ro具有与加州海兔蜗牛神经元蛋白407相似的分子量、等电点和显著的氨基酸序列。这些同源性表明这种Ro蛋白具有非常基本的细胞功能，可能部分涉及钙结合。
