[Rearrangement of nucleoli in hepatocytes stimulated for proliferation and enhancement of their transcription function].
The nucleoli of normally functioning guinea-pig hepatocytes that have a nucleolonemal (strand-like) organization differ from identical nucleoli of other cells. Their nucleolonema consists as a rule of a fibrillar component with 45S RNA and is poor in granulas that contain pre-rNA molecules of an intermediate size and 28S rRNA, a dense fibrillar component with nascent rRNPs in its composition was not revealed. In hepatocytes stimulated by a 2/3 liver resection rearrangements in nucleoli were found. This brought to a conclusion that rRNA metabolism undergoes some changes. In 2.5 and 5 hours after the resection the hepatocytes' nucleoli were characteristic of a greater thickness of strands and a smaller size of vacuoles, appearance of distinct zones of the dense fibrillar component and an increased amount of RNP-granules. All these observations taken together point out at an increased synthesis and processing of rRNA at early stages of the prereplicative period. In 9 hours the character of changes in nucleoli was different: the vacuoles were considerably widened, whereas the thickness of strands that consisted of a well-expressed dense fibrillar, fibrillar and granular components was lesser. Such rearrangement points out at an increased transport of preribosomes from the nucleolus, a high level of synthesis and processing of nascent RNP-product being maintained. The changes of nucleolar RNP-component were followed by appearance of greater blocks of perinucleolar condensed chromatin, which may be connected with "cutting-off" some tissue-specific genes and initiation of functioning of the mitotic operon genes.
D000818:Animals; D002455:Cell Division; D002466:Cell Nucleolus / Q000378:metabolism* / Q000648:ultrastructure; D006168:Guinea Pigs; D008099:Liver / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D008854:Microscopy, Electron; D009690:Nucleic Acid Conformation; D012313:RNA / Q000096:biosynthesis* / Q000648:ultrastructure; D014158:Transcription, Genetic
D012313:RNA
Perestroĭki iadryshek v stimulirovannykh k proliferatsii gepatotsitakh i usilenie ikh transkriptsionnoĭ funktsii.