The silver-stained NOR and argentophilic nuclear proteins in early mouse embryogenesis: a cytological study

Dyban, A. P.; Severova, E L; Зацепина, О. В.; Chentsov, Yu. S.

doi:10.1016/0922-3371(90)90119-h

Cited by 18 publications

(5 citation statements)

References 34 publications

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“…It has long been known that in mouse embryos the so called "Ag-NOR proteins," which are characteristic for active ribosomal genes, associate with the chromosomal NORs starting from the second cleavage mitosis (Dyban et al, 1990;Engel et al, 1977). The complete set of the NOR-associated proteins during somatic mitosis is still not completely known, but a few of them were identified, namely pol I (RPA190), UBF, p135, p50, TBP, and a TBPassociated factor, TAF I 100 (Roussel et al, 1996).…”

Section: Discussionmentioning

confidence: 99%

The Step-Wise Assembly of a Functional Nucleolus in Preimplantation Mouse Embryos Involves the Cajal (Coiled) Body

Зацепина

Baly

Chebrout

et al. 2003

Developmental Biology

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After fertilization, ribosomal RNA synthesis is silenced during a period which depends on the species. Data concerning the reassembly of a functional nucleolus remain scarce. We have examined by immunocytochemistry, Western blots, and BrUTP microinjection the dynamics of major nucleolar proteins during the first cycles of mouse embryogenesis, in relation to rDNA transcription sites and coilin, a marker of Cajal bodies. We show that: (1) the reinitiation of rDNA transcription occurs at the two-cell stage, 44-45 h after hCG injection (hphCG), at the surface of the nucleolar precursor bodies (NPBs), where the RNA polymerase I (pol I) transcription complex is recruited 4-5 h before; (2) the NPBs are not equal in their ability to support recruitment of pol I and rDNA transcription; (3) maternally inherited fibrillarin undergoes a dynamic redistribution during the second cell stage, together with coilin, leading to the assembly of the Cajal body around 40 hphCG; and (4) the pol I complex is first recruited to the Cajal body before reaching its rDNA template. We also find that fibrillarin and B23 are both directly assembled around NPBs prior to ongoing pre-rRNA synthesis. Altogether, our results reveal a role of the Cajal bodies in the building of a functional nucleolus.

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Section: Discussionmentioning

confidence: 99%

The Step-Wise Assembly of a Functional Nucleolus in Preimplantation Mouse Embryos Involves the Cajal (Coiled) Body

Зацепина

Baly

Chebrout

et al. 2003

Developmental Biology

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“…The amount of argentophilic materials related to NORs in mitosis directly correlates with the level of transcription of the ribosomal genes at the preceding interphase (Derenzini et al, 1995;Sirri et al, 2000;Derenzini, 2000). Similar patterns have also been described for cells of cleaving mammalian embryos, including mouse embryos (Dyban et al, 1990;Patkin et al, 1992). Hence, it can be proposed that the increase in the number of Ag-NORs in the course of ES cell cultivation is a result of the activation of rDNA transcription and synthesis of ribosomes in these cells.…”

Section: Discussionmentioning

confidence: 66%

Activation of nucleolus organizing regions during in vitro cultivation of mouse R1 embryonic stem cells

et al. 2005

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We studied the activities of ribosomal genes (nucleolus organizing regions) at successive stages of cultivation of the mouse R1 embryonic stem cells. The total number and number of active nucleolar organizers were estimated by means of in situ hybridization with mouse rDNA probes and argentophilic staining of nucleolus forming chromosomes regions from the 16th until the 32nd passages. The data we obtained suggest that the total number of nucleolar organizers per metaphase plate was constant (as a rule, eight), while the mean number of active nucleolar organizers progressively increased from the early (16th) to the late (32nd) passages: 5.2 ± 0.4 versus 7.4 ± 0.9 argentophilic organizers per cell. Cell heterogeneity by the number of active nucleolar organizers also increased during the late passages. Taken together, these data suggest activation of ribosomal DNA transcription and synthesis of ribosomes during cultivation of mouse R1 embryonic stem cells. Based on the experimental and published data, it has been proposed that activation of ribosomal genes correlates in time with a decreased capacity of embryonic stem cells for pluripotent differentiation.

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“…The 'rings' reflecting a concentration of mitochondria around nuclei may be explained by association of the mitochondria with microtubules which provide for nuclear migration to the centre of BFP, just like during formation of the zygote (Shatten et al, 1985). Furthermore, at the 2-cell stage the very important events such as a switch of control of embryogenesis from maternal to embryonic genome (Flach et al, 1982) and the beginning of nucleolar activation (Dyban et al, 1990) are taking place, but as nuclear pores are not yet numerous this is seemingly compensated by transport of some material from the nucleus to the cytoplasm via nuclear blebs (Calarco & Brown, 1969;Sekirina et al, in press). Thus the special morpho-functional state of the nucleus and nucleo-cytoplasmic metabolic cooperation may predetermine a perinuclear concentration of mitochondria in mouse embryos at the 2-cell stage.…”

Section: Discussionmentioning

confidence: 99%

The behaviour of mitochondria and cell integration during somatic hybridisation of sister blastomeres of the 2-cell mouse embryo

Sekirina

Bogoliubova

Antonova

et al. 1997

Zygote

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The capacity of sister blastomeres of mouse embryos for induced fusion changed during the 2-cell stage. It was at low level (24%) at the early 2-cell stage, increased and reached 98.5% at the middle 2-cell stage and fell sharply to 31% at the late 2-cell stage. At the time corresponding to the G 2 /Mphase of the cell cycle the blastomeres fused in only 8% of cases. Vital staining of 2-cell embryos by rhodamine 123 showed that the mitochondria were dispersed throughout the cytoplasm with a ringlike (around the nucleus) or spot-like (over the metaphase plate) concentration in the centre of each blastomere. At the periphery of blastomeres the mitochondrial content was low. The behaviour of the mitochondria reflected the subsequent events of structural and functional integration of the sister blastomeres under induced fusion: a discernible boundary between partners during 30min after electrofusion or 1 h after fusion with polyethylene glycol; movement of the two 'rings' to the centre of the blastomere fusion products (BFP) to form one large bright 'spot' over the common metaphase plate; mitochondria outlining the shape of the spindle and connection between sister blastomeres until completion of the first mitosis of BFP. The data obtained suggest that fusion of the blastomeres does not lead to extensive changes in the hybrid cytoplasm and integration of nuclear material is taking place only at metaphase stage. Cytogenetic examination of BFP at the 2-cell stage confirmed reconstruction of the tetraploid embryos and found that sister blastomeres of such embryos could asynchronously enter the next cleavage division similarly to normal diploid 2-cell embryos.

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The silver-stained NOR and argentophilic nuclear proteins in early mouse embryogenesis: a cytological study

Cited by 18 publications

References 34 publications

The Step-Wise Assembly of a Functional Nucleolus in Preimplantation Mouse Embryos Involves the Cajal (Coiled) Body

The Step-Wise Assembly of a Functional Nucleolus in Preimplantation Mouse Embryos Involves the Cajal (Coiled) Body

Activation of nucleolus organizing regions during in vitro cultivation of mouse R1 embryonic stem cells

The behaviour of mitochondria and cell integration during somatic hybridisation of sister blastomeres of the 2-cell mouse embryo

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