Therman E, Sarto G E, Stubblefield P A
Hum Genet. 1983;63(1):13-8. doi: 10.1007/BF00285390.
The concept and role of endomitosis is reevaluated in the light of observations on three organisms. Endomitosis which morphologically agrees with Geitler's (1939) classical definition is compared in tapetal cells of the liliaceous plant Eremurus, in the septal cells of the testicular follicles of the grasshopper Melanoplus, and in human cells from normal and molar trophoblasts and cervical cancer. These observations, together with those of Kidnadze and Istomina (1980), show that functionally at least two fundamentally different types of endomitosis exist, although morphologically the stages resemble each other in the three organisms. In the first type, exemplified by Eremurus, each endomitosis leads to a chromosome constitution which represents one level higher ploidy, a course that has been assumed to be characteristic of endomitosis in general. The second type, observed in its most characteristic form in the grasshopper, seems to be stationary: no DNA synthesis occurs, but an intensive RNA synthesis takes place. Presumably such cells have reached a final state in their development and are specialized in manufacturing one or more gene products. Endomitosis in normal placenta comes near this type, although DNA synthesis takes place in occasional cells. However, similar endomitotic nuclei in the hydatiform moles are in the process of DNA synthesis. When endomitosis is analyzed in different organisms and tissues, the observation that this process is not one entity should be kept in mind.
根据对三种生物的观察结果，对核内有丝分裂的概念和作用进行了重新评估。在百合科植物独尾草的绒毡层细胞、蝗虫黑蝗精巢滤泡的隔膜细胞以及来自正常和葡萄胎滋养层及宫颈癌的人类细胞中，对形态上符合盖特勒（1939年）经典定义的核内有丝分裂进行了比较。这些观察结果，连同基德纳泽和伊斯托米娜（1980年）的观察结果表明，尽管在这三种生物中核内有丝分裂的各个阶段在形态上彼此相似，但在功能上至少存在两种根本不同类型的核内有丝分裂。在第一种类型中，以独尾草为例，每次核内有丝分裂都会导致一种染色体组成，其代表的倍性水平更高，这一过程通常被认为是核内有丝分裂的特征。第二种类型，在蝗虫中以其最典型的形式被观察到，似乎是静止的：不发生DNA合成，但会进行大量的RNA合成。据推测，这类细胞在其发育过程中已达到最终状态，并专门用于制造一种或多种基因产物。正常胎盘中的核内有丝分裂接近这种类型，尽管偶尔会有细胞进行DNA合成。然而，葡萄胎中类似的核内有丝分裂核正处于DNA合成过程中。当在不同的生物和组织中分析核内有丝分裂时，应牢记这一过程并非单一实体这一观察结果。
