On some structural and evolutionary aspects of rDNA amplification in oogenesis of Trachemys scripta turtles
Autor: | Elena Gaginskaya, Elena I. Koshel, Svetlana Galkina, Asya Davidian, Alexander Dyomin, Alsu Saifitdinova |
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Rok vydání: | 2020 |
Předmět: |
0301 basic medicine
Amphibian DNA Replication Histology Nucleolus Oogenesis DNA Ribosomal Pathology and Forensic Medicine 03 medical and health sciences 0302 clinical medicine biology.animal Extrachromosomal DNA medicine RNA Precursors Animals Cell Proliferation Fibrillarin biology Cell Biology DNA-Directed RNA Polymerases Oocyte Biological Evolution Cell biology Turtles 030104 developmental biology Lampbrush chromosome medicine.anatomical_structure Oocytes Female Vitellogenesis 030217 neurology & neurosurgery Cell Nucleolus |
Zdroj: | Cell and tissue research. 383(2) |
ISSN: | 1432-0878 |
Popis: | The features of rDNA amplification have been studied in oocytes of the red-eared slider Trachemys scripta using a number of specific histochemical and cytomolecular methods. A single nucleolus in early diplotene oocytes is associated with the nucleolus organizer region (NOR). With oocyte growth, the number of nucleoli increases dramatically and reaches hundreds by the lampbrush chromosome stage (pre-vitellogenesis). RNA-polymerase I, fibrillarin, and PCNA immunodetection in the amplified nucleoli and FISH of the 5’ETS probe to the oocyte nuclear content suggest pre-rRNA and rDNA synthesis in the nucleoli at all stages studied. This implies a continuous reproduction of the nucleoli during oocyte development from early diplotene up to vitellogenesis. The data obtained offer a different way for rDNA amplification and formation of extrachromosomal nucleoli in turtle oocytes compared with the amplified nucleoli formation in amphibian and fish oocytes. In the Sauropsida clade of Archelosauria, which includes turtles, crocodiles, and birds, rDNA function is known to be suppressed in avian oogenesis during the lampbrush stage (Gaginskaya et al. in Cytogenet Genome Res 124:251–267, 2009). |
Databáze: | OpenAIRE |
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