多头绒泡菌类cyclinB1蛋白在细胞周期中的变化

以自然同步化的多头绒泡菌（Physarum polycephalumL.)为材料，经抗cyclinB1抗体的免疫印迹和免疫电镜实验观察结果表明，多头绒泡菌中含有类cyclinB1蛋白，该蛋白的含量和细胞内位置在细胞周期进程中存在着动态变化。类cyclinB1蛋白在S期开始合成并在细胞质中积累，G2晚期开始进入细胞核，该蛋白在细胞质和细胞核中含量逐渐增加。有丝分裂中期时达最大值。后末期时骤然消失，在G2晚期到有丝分裂中期期间，类cyclinB1蛋白既是细胞核蛋白又是细胞质蛋白，细胞质是类cyclinB1蛋白的主要存在区域，细胞核中的类cyclinB1蛋白主要结合于染色体和核仁区域。

Variation of Cyclin B1-like Protein During the Cell Cycle of Physarum polycephalum

Physarum polycephalum L., a naturally synchronized myxomycophyta, was demonstrated to contain a cyclin B1-like protein by Western blot and immunoelectron microscopy. The content and subcellular location of the protein varied during the cell cycle. The cyclin B1-like protein was first detected in the plasmodia of S phase while it did not appear in the nuclei until late G2 phase. The content of the protein in both the plasmodia and nuclei rose gradually onwards, peaked at metaphase and disappeared abruptly at ana-telophase. The protein was found to be distributed in both the cytoplasm and nuclei in late G2 phase and metaphase. In nuclei, the protein was mainly located in the chromosomal and nucleolar areas. The results suggest that the cyclin B1-like protein of P. polycephalum begins to be synthesized at S phase, enters the nuclei at late G2 phase, accumulates in both cytoplasm and nuclei onwards and breaks down at ana-telophase. The results also suggest that the cyclin B1-like protein acts as a cytoplasmic-nuclear protein during certain phases of the cell cycle.