title: Non-isotopic detection of nucleolar transcription in pre-implantation mouse embryos.
abstract: Nucleolar transcription was analysed in permeabilized pre-implantation mouse embryos at the four-cell, eight-cell, morula and early blastocyst stages using confocal microscopy to detect incorporated 5-bromouridine. The results demonstrated that the patterns of nucleolar transcription sites were common for all embryonic stages studied. They consisted most frequently of tightly associated groups of transcription foci similar to those encountered in somatic interphase cells. In addition, the nucleologenesis accompanying each cell cycle apparently gave rise to a different fluorescent pattern, that is to spatially separated fluorescent foci in the cells just after the resumption of rRNA synthesis. An immunoelectron microscopic analysis of the nucleolar transcription was also performed in the eight-cell embryos. A signal, usually consisting of clustered gold particles, was found specifically within nucleolar dense fibrillar components. This result was in agreement with established findings, which identify dense fibrillar component as the major site of nucleolar transcription in somatic cells.
authors.affiliation: Department of Cell Biology, Academy of Sciences of Czech Republic, Prague, Czech Republic.
authors.forename: K
authors.initials: K
authors.lastname: Koberna
authors.forename: V
authors.initials: V
authors.lastname: Landa
authors.forename: J
authors.initials: J
authors.lastname: Kanka
authors.forename: A
authors.initials: A
authors.lastname: Pliss
authors.forename: M
authors.initials: M
authors.lastname: Eltsov
authors.forename: D
authors.initials: D
authors.lastname: Stanĕk
authors.forename: I
authors.initials: I
authors.lastname: Raska
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000378:metabolism* / Q000648:ultrastructure; D001976:Bromouracil / Q000031:analogs & derivatives; D002466:Cell Nucleolus / Q000378:metabolism*; D047108:Embryonic Development; D005260:Female; D051379:Mice; D008810:Mice, Inbred C57BL; D018613:Microscopy, Confocal; D016253:Microscopy, Immunoelectron; D009028:Morula / Q000378:metabolism / Q000648:ultrastructure; D011247:Pregnancy; D014158:Transcription, Genetic; D014529:Uridine / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: D001976:Bromouracil; C006824:5-bromouridine; D014529:Uridine