The ciliated protist Tetrahymena thermophila is a well-known model organism with typical nuclear dimorphism containing a somatic macronucleus (MAC) and a germline micronucleus (MIC). The presence in the same cell compartment of two nuclei with distinctly different structural and functional properties provides an ideal model system to explore mechanisms of genome maintenance. Although methods for the isolation of MIC have been available for many years, cross-contamination and DNA degradation remain unresolved. Here, we describe a reliable and quick method to isolate MIC with high purity and DNA integrity in T. thermophila. Different factors are examined to optimize the MIC purification. The MAC contamination ratio in purified MIC is about 0.19% and DNA integrity of purified MIC is maintained. We also establish a more accurate method to detect the contamination rate of nuclei including microscopic observation and PCR detection. This study will facilitate further epigenetic research in Tetrahymena.

纤毛原生生物嗜热四膜虫是一种众所周知的模式生物，具有典型的核二态性，包含体细胞大核 (MAC) 和种系微核 (MIC)。具有明显不同结构和功能特性的两个细胞核在同一细胞区室中的存在提供了一个理想的模型系统来探索基因组维护的机制。尽管分离 MIC 的方法已经存在多年，但交叉污染和 DNA 降解问题仍未解决。在这里，我们描述了一种可靠且快速的方法，用于在嗜热嗜热菌中分离具有高纯度和 DNA 完整性的 MIC. 检查不同的因素以优化 MIC 纯化。纯化 MIC 中的 MAC 污染率约为 0.19%，并且保持了纯化 MIC 的 DNA 完整性。我们还建立了更准确的检测细胞核污染率的方法，包括显微镜观察和PCR检测。这项研究将促进四膜虫的进一步表观遗传研究。