Gorovsky M A, Keevert J B
Proc Natl Acad Sci U S A. 1975 Sep;72(9):3536-40. doi: 10.1073/pnas.72.9.3536.
Macronuclei of the ciliated protozoan Tetrahymena pyriformis contain at least five classes of histones, including two with properties like those of histones F3 and F1 of higher eukaryotes. Micronuclei isolated under identical conditions contain little or no detectable F3 or F1. Digestion of both macronuclei and micronuclei with staphylococcal nuclease results in DNA fragments of discrete sizes. The electrophoretic mobilities of the larger fragments suggest that they are oligomers of the smallest ones. These results indicate that the periodic subunit structure observed in the chromatin of higher organisms also occurs in protozoans, and that this structure does not depend on the presence of either histone F1 or F3, even in an organism which has the genetic information for synthesizing these proteins.
梨形四膜虫这种纤毛原生动物的大核含有至少五类组蛋白，其中两类组蛋白的特性与高等真核生物的组蛋白F3和F1相似。在相同条件下分离出的小核几乎不含或检测不到F3或F1。用葡萄球菌核酸酶消化大核和小核都会产生大小离散的DNA片段。较大片段的电泳迁移率表明它们是最小片段的寡聚体。这些结果表明，在高等生物染色质中观察到的周期性亚基结构在原生动物中也存在，并且这种结构不依赖于组蛋白F1或F3的存在，即使在具有合成这些蛋白质的遗传信息的生物体中也是如此。
