title: Additional nucleoli and NOR activity during meiotic prophase I in larch (Larix decidua Mill.).
abstract: Transcriptional activity was investigated in successive stages of prophase I (male meiosis) of larch meiocytes. Br-UTP incorporated into RNA was detected by light and electron microscopy. Two peaks of RNA synthesis were identified in the nucleolus. The first occurred during the zygotene-pachytene stage and the second (not previously described in plant meiocytes) in the diplotene. These processes correlated with a considerable increase in nucleolus volume during these periods. At the end of the zygotene, several perinucleolar structures lying close to each other and containing rRNA, argyrophilic proteins, U3 small nucleolar RNA, and fibrillarin were observed. The occurrence of newly formed RNA was also observed in these structures. This suggests that the observed perinucleolar structures correspond to the additional nucleoli known from animals.
authors: Department of Cell Biology, Institute of General and Molecular Biology, Nicolaus Copernicus University, Toruń, Poland. darsmol@uni.torun.pl
authors: D J
authors: DJ
authors: Smoliński
authors: J
authors: J
authors: Niedojadło
authors: A
authors: A
authors: Noble
authors: A
authors: A
authors: Górska-Brylass
mesh_terms: D002466:Cell Nucleolus / Q000378:metabolism* / Q000648:ultrastructure; D018506:Gene Expression Regulation, Plant; D028221:Larix / Q000166:cytology* / Q000235:genetics / Q000648:ultrastructure; D049469:Meiotic Prophase I; D008954:Models, Biological; D009697:Nucleolus Organizer Region / Q000378:metabolism*; D053141:Organelle Size; D014158:Transcription, Genetic