Olins D E, Olins A L, Cacheiro L H, Tan E M
University of Tennessee-Oak Ridge, Graduate School of Biomedical Sciences 37831.
J Cell Biol. 1989 Oct;109(4 Pt 1):1399-410. doi: 10.1083/jcb.109.4.1399.
Human autoimmune sera specific for proliferating cell nuclear antigen (PCNA)/cyclin (auxiliary protein for DNA polymerase delta) demonstrated the presence of epitopes within the macro- and micronuclei of the hypotrichous ciliated protozoa Euplotes eurystomus. Tightly bound PCNA/cyclin was localized at the site of DNA synthesis in macronuclei, the rear zone of the replication band. Starvation or heat shock, conditions that reduce macronuclear replication, resulted in a decrease of PCNA/cyclin in replication bands. Micronuclei also exhibited PCNA/cyclin localization which persisted for a large proportion of the vegetative cell cycle and exhibited significant resistance to adverse culture conditions. Immunoprecipitation of 35S-labeled soluble Euplotes proteins with PCNA/cyclin autoimmune sera revealed a spectrum of low molecular mass proteins. PCNA/cyclin-like proteins have now been observed in the widely divergent species: human, rat, amphibian, yeast, and ciliated protozoa.
针对增殖细胞核抗原(PCNA)/细胞周期蛋白(DNA聚合酶δ的辅助蛋白)的人自身免疫血清显示,在多核纤毛虫阔口游仆虫的大核和小核内存在表位。紧密结合的PCNA/细胞周期蛋白定位于大核中DNA合成的位点,即复制带的后部区域。饥饿或热休克这些会减少大核复制的条件,导致复制带中PCNA/细胞周期蛋白减少。小核也表现出PCNA/细胞周期蛋白定位,这种定位在大部分营养细胞周期中持续存在,并且对不利的培养条件表现出显著抗性。用PCNA/细胞周期蛋白自身免疫血清对35S标记的游仆虫可溶性蛋白进行免疫沉淀,揭示了一系列低分子量蛋白。现已在广泛不同的物种中观察到PCNA/细胞周期蛋白样蛋白:人类、大鼠、两栖动物、酵母和纤毛虫。