Ramos-Morales F, Infante C, Fedriani C, Bornens M, Rios R M
Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, Spain.
J Biol Chem. 1998 Jan 16;273(3):1634-9. doi: 10.1074/jbc.273.3.1634.
The serum from a patient with Sjögren's syndrome (RM serum) was used to screen a human testis cDNA expression library. A cDNA of 865 base pairs containing the entire coding sequence for a novel protein was isolated. The 14-kDa predicted protein contains an acidic domain (amino acids 6-80) with a high frequency of heptad repeats characteristic of alpha-helices that form dimeric coiled-coil structures and an alkaline carboxyl-terminal domain (amino acids 81-119). It seems to be widely expressed, but its expression level varies depending on tissues. A protein of apparent molecular mass of 14 kDa was immunoprecipitated from cell lysates by the autoimmune serum, and it was recognized by rabbit antibodies raised to a recombinant bacterial fusion protein generated from the cDNA clone. Conventional and confocal immunofluorescence microscopy on HeLa and 3T3 cells transiently transfected with a tagged form of the protein showed numerous punctate structures scattered throughout the nucleus. This novel protein has been termed NA14 for Nuclear Autoantigen of 14 kDa.
用干燥综合征患者的血清（RM血清）筛选人睾丸cDNA表达文库。分离出一个865个碱基对的cDNA，它包含一种新蛋白质的完整编码序列。预测的14 kDa蛋白质包含一个酸性结构域（氨基酸6 - 80），具有形成二聚体卷曲螺旋结构的α - 螺旋特有的七肽重复高频序列，以及一个碱性羧基末端结构域（氨基酸81 - 119）。它似乎广泛表达，但其表达水平因组织而异。通过自身免疫血清从细胞裂解物中免疫沉淀出表观分子量为14 kDa的蛋白质，并且它能被针对由该cDNA克隆产生的重组细菌融合蛋白制备的兔抗体识别。对用该蛋白质的标记形式瞬时转染的HeLa细胞和3T3细胞进行常规和共聚焦免疫荧光显微镜检查，结果显示在整个细胞核中散布着许多点状结构。这种新蛋白质被命名为NA14，即14 kDa的核自身抗原。
