Higashi Y, Takahashi K P, Uchimoto T, Morisawa S, Inoue A
Department of Biochemistry, Osaka City University Medical School, Japan.
Cell Struct Funct. 1990 Apr;15(2):113-6. doi: 10.1247/csf.15.113.
S1 proteins (A, B, C and D) are a group of nuclear proteins, isolated by lowering pH to 4.9 of the reaction supernatant of hepatocyte nuclei that had been mildly digested with DNase I. Protein B, apparently ubiquitous in vertebrate cells, was prepared from rat liver and used to immunize a rabbit. The raised antiserum specifically reacted with S1 proteins; it reacted not only with protein B, but also with C and D. Immunoblotting demonstrated that these proteins occurred exclusively in the nucleus, being absent in the cytosol, microsome and mitochondrial fractions. Indirect immunofluorescence of liver tissue sections confirmed their nuclear localization, and further showed that the antibody selectively stained extranucleolar regions of the cell nucleus. These findings suggest that the anti-S1 antibody is specific to S1 proteins and may be useful for their structural and functional studies.
S1蛋白（A、B、C和D）是一组核蛋白，通过将经脱氧核糖核酸酶I轻度消化的肝细胞核反应上清液的pH值降至4.9而分离得到。蛋白B显然在脊椎动物细胞中普遍存在，它是从大鼠肝脏中制备出来并用于免疫一只兔子的。产生的抗血清与S1蛋白发生特异性反应；它不仅与蛋白B反应，还与蛋白C和D反应。免疫印迹法表明这些蛋白仅存在于细胞核中，在细胞质、微粒体和线粒体组分中不存在。肝组织切片的间接免疫荧光证实了它们在细胞核中的定位，并进一步表明该抗体选择性地染色细胞核的核仁外区域。这些发现表明抗S1抗体对S1蛋白具有特异性，可能对其结构和功能研究有用。
