title: Evidence for postmeiotic expression of ribosomal RNA genes during male gametogenesis.
abstract: Pre- and postmeiotic stages of male gametogenesis of 10 different vertebrate species belonging to mammals, birds, amphibians, and fishes were subjected to the Ag-AS staining technique (Goodpasture and Bloom, 1975). A uniform pattern of silver-staining is observable during spermatogenesis of the different vertebrate species. Silver-staining is present in spermatogonia and during the whole period of meiotic prophase, but totally absent during diakinesis and metaphase II of meiosis. In early spermatids silver-staining reappears and only disappears around the beginning of elongation of the spermatid nucleus. Since the Ag-AS technique is believed to stain only transcriptionally active nucleolus organizer regions, our findings indicate that ribosomal RNA genes become reactivated in the haploid spermatid.
mesh_terms: D000818:Animals; D001001:Anura; D002645:Chickens; D005796:Genes; D006168:Guinea Pigs; D006801:Humans; D008297:Male; D008540:Meiosis; D008677:Metaphase; D051379:Mice; D011418:Prophase; D012335:RNA, Ribosomal / Q000235:genetics*; D051381:Rats; D012455:Salamandridae; D013087:Spermatids; D013091:Spermatogenesis; D013093:Spermatogonia; D014337:Trout
chemical_list: D012335:RNA, Ribosomal