Chatterjee A, Freeman J W, Busch H
Cancer Res. 1987 Feb 15;47(4):1123-9.
The present study reports the identification and partial characterization of a novel Mr 40,000 nucleolar antigen (P40) by monoclonal antibodies. Monoclonal antibodies to this protein were obtained when a nucleolar protein extract separated from the immunodominant protein C23 was used to immunize BALB/c mice; 12 hybridoma clones produced antibodies to this protein. P40 was not detected in normal human kidney, liver, and leukocytes but was readily demonstrable in a variety of human malignant tissues. This newly identified P40 antigen differs in its specific nucleolar localization from cyclin (proliferating cell nuclear antigen), a Mr 35,000 antigen which is largely in the nucleoplasm. In addition, cyclin appears in the nucleolus in S-phase; P40 appears in the nucleolus 6 h after refeeding serum-starved HeLa cells.
本研究报告了通过单克隆抗体对一种新的40,000分子量核仁抗原（P40）的鉴定及部分特性分析。当用从免疫显性蛋白C23中分离出的核仁蛋白提取物免疫BALB/c小鼠时，获得了针对该蛋白的单克隆抗体；12个杂交瘤克隆产生了针对该蛋白的抗体。在正常人类肾脏、肝脏和白细胞中未检测到P40，但在多种人类恶性组织中很容易检测到。这种新鉴定的P40抗原在其特定的核仁定位上与细胞周期蛋白（增殖细胞核抗原）不同，细胞周期蛋白是一种35,000分子量的抗原，主要存在于核质中。此外，细胞周期蛋白在S期出现在核仁中；血清饥饿的HeLa细胞重新喂食6小时后，P40出现在核仁中。
