Schmid M, Löser C, Schmidtke J, Engel W
Chromosoma. 1982;86(2):149-79. doi: 10.1007/BF00288674.
The patterns of activity of the nucleolus organizer regions (NORs) in the spermatogeneses of ten species of all non-mammalian classes of vertebrates and one species of the cephalochordates were investigated with the silver (Ag)-staining technique. The Ag-stainability of the NORs is a measure of the transcriptional activity of the ribosomal RNA genes. In all species, there is a very similar pattern of NOR-activity in the various stages of spermatogenesis. The qualitative analysis of the Ag-stainability of the NORs was in very good agreement with the results obtained for mammals: Ag-stained NORs are detectable during the entire meiotic prophase up to the pachytene stage, completely absent in the meiotic metaphases I and II, and again demonstrable in early spermatid nuclei. The results confirm the occurrence of postmeiotic reactivation of the RNA genes. The preferential inhibition of rRNA synthesis by low doses of actinomycin D induced a rapid decline of the Ag-stainability of the postmeiotically reactivated NORs. The significance of the evolutionary conservation of the postmeiotic NOR-reactivation is discussed.
利用银（Ag）染色技术，研究了所有非哺乳类脊椎动物的十个物种以及头索动物的一个物种精子发生过程中核仁组织区（NORs）的活性模式。NORs的银染色性是核糖体RNA基因转录活性的一种衡量指标。在所有物种中，精子发生的各个阶段都存在非常相似的NOR活性模式。NORs银染色性的定性分析与哺乳动物的结果非常一致：在整个减数分裂前期直至粗线期都可检测到银染的NORs，在减数分裂中期I和II完全缺失，而在早期精子细胞核中又可再次显示。结果证实了RNA基因减数分裂后重新激活的发生。低剂量放线菌素D对rRNA合成的优先抑制导致减数分裂后重新激活的NORs银染色性迅速下降。讨论了减数分裂后NOR重新激活的进化保守性的意义。
