On some structural and evolutionary aspects of rDNA amplification in oogenesis of Trachemys scripta turtles.
Cell Tissue Res
; 383(2): 853-864, 2021 Feb.
Article
em En
| MEDLINE
| ID: mdl-32897424
ABSTRACT
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 124251-267, 2009).
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Oogênese
/
Tartarugas
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DNA Ribossômico
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Evolução Biológica
Limite:
Animals
Idioma:
En
Revista:
Cell Tissue Res
Ano de publicação:
2021
Tipo de documento:
Article
País de afiliação:
Federação Russa