Pietropaolo M, Castaño L, Babu S, Buelow R, Kuo Y L, Martin S, Martin A, Powers A C, Prochazka M, Naggert J
Barbara Davis Center for Childhood Diabetes, University of Colorado Health Science Center, Denver 80262.
J Clin Invest. 1993 Jul;92(1):359-71. doi: 10.1172/JCI116574.
We have identified a novel 69-kD peptide autoantigen (ICA69) associated with insulin-dependent diabetes mellitus (IDDM) by screening a human islet lambda gt11 cDNA expression library with cytoplasmic islet cell antibody positive sera from relatives of IDDM patients who progressed to the overt disease. The deduced open reading frame of the ICA69 cDNA predicts a 483-amino acid protein. ICA69 shows no nucleotide or amino acid sequence relation to any known sequence in GenBank, except for two short regions of similarity with BSA. The ICA69 cDNA probe hybridizes with a 2-kb mRNA in poly(A+) RNA from human pancreas, brain, heart, thyroid, and kidney, but not with skeletal muscle, placenta, spleen, or ovary. Expression of ICA69 was also detected in beta cells and cell lines, as well as in tumoral tissue of islet cell origin. The native ICA69 molecule migrates to 69 kD in SDS-PAGE as detected with specific antibodies. Serum samples from relatives of IDDM patients specifically reacted with affinity-purified recombinant ICA69 on Western blotting. The structural gene for ICA69 was designated ICA1. A homologue in the mouse, designated Ica-1 was mapped to the proximal end of chromosome 6 (within 6 cM of the Met protooncogene). ICA69 adds a novel autoantigen to the family of identified islet target molecules, and by the manner of its identification and characterization large amounts of antigen are available for development of quantitative, convenient predictive assays for autoantibodies and analysis of the role of this molecule in diabetes autoimmunity, as well as its physiologic function.
我们通过用来自进展为显性疾病的胰岛素依赖型糖尿病（IDDM）患者亲属的胰岛细胞胞浆抗体阳性血清筛选人胰岛λgt11 cDNA表达文库，鉴定出一种与IDDM相关的新型69-kD肽自身抗原（ICA69）。ICA69 cDNA推导的开放阅读框预测有一个483个氨基酸的蛋白质。ICA69除了与牛血清白蛋白有两个短的相似区域外，与GenBank中任何已知序列均无核苷酸或氨基酸序列关系。ICA69 cDNA探针与人胰腺、脑、心脏、甲状腺和肾脏的多聚腺苷酸（poly(A+)）RNA中的2-kb mRNA杂交，但不与骨骼肌、胎盘、脾脏或卵巢杂交。在β细胞和细胞系以及胰岛细胞来源的肿瘤组织中也检测到了ICA69的表达。用特异性抗体检测发现，天然ICA69分子在SDS-PAGE中迁移至69 kD。IDDM患者亲属的血清样本在蛋白质印迹法中与亲和纯化的重组ICA69发生特异性反应。ICA69的结构基因被命名为ICA1。在小鼠中的一个同源物，命名为Ica-1，被定位到6号染色体近端（在原癌基因Met的6 cM范围内）。ICA69为已鉴定的胰岛靶分子家族增添了一种新型自身抗原，并且通过其鉴定和表征方式，可获得大量抗原，用于开发针对自身抗体的定量便捷预测检测方法，以及分析该分子在糖尿病自身免疫中的作用及其生理功能。
