Role of karyoplasm in the emergence of capacity of egg cytoplasm to induce DNA synthesis in transplanted sperm nuclei

Development ◽  
1976 ◽  
Vol 36 (1) ◽  
pp. 67-72
Author(s):  
M. N. Skoblina

The behaviour of sperm nuclei was studied both in the cytoplasm of intact toad oocytes undergoing maturation and the cytoplasm of oocytes matured without germinal vesicles. The behaviour of the nuclei of pronase-treated sperm injected in the mature egg cytoplasm was shown to be exactly similar to that of the sperm nucleus after fertilization, i.e. they swelled, synthesized DNA, and divided. No changes in such sperm nuclei could be detected in the cytoplasm of the oocytes matured without germinal vesicles.

Zygote ◽  
1998 ◽  
Vol 6 (1) ◽  
pp. 39-45 ◽  
Author(s):  
Yasutaka Maeda ◽  
Hiroko Yanagimachi ◽  
Hiroyuki Tateno ◽  
Noriko Usui ◽  
R. Yanagimachi

SummarySperm nuclei incorporated into the cytoplasm (ooplasm) of fertilised mouse eggs at the pronuclear stage remain condensed, whereas those injected into male or female pronuclei decondense. Similarly, sperm nuclei injected into germinal vesicles of immature oocytes or the nuclei of 2-cell embryos decondense, while those entering the cytoplasm of these oocytes / embryos do not. These facts seem to suggest that factors necessary for the decondensation of sperm nucleus are present in interphase nuclei and are released into the ooplasm during nuclear envelope breakdown. Nucleoplasmin, which is synthesised in the cytoplasm and accumulated within the nucleus, is likely a major candidate for these factors.


Development ◽  
1979 ◽  
Vol 52 (1) ◽  
pp. 39-48
Author(s):  
B. T. Wakimoto

Cytological and autoradiographic studies were done to investigate the cytoplasmic control of DMA synthesis under conditions of physiological polyspermy. The DNA synthetic phases of the egg, principal sperm and accessory sperm nuclei were determined and correlated with nuclear morphology and developmental fate. Results show that accessory sperm nuclei undergo morphological transition to pronuclei. Their DNA synthetic phase is the same as that of the principal sperm nucleus. Hence accessory sperm nuclei are capable of initiating and completing DNA replication before any cytological evidence of their degeneration is observed


Author(s):  
A. Sosa ◽  
L. Calzada

The dependence of nuclear metabolism on the function of the nuclear membrane is not well understood. Whether or not the function of the nuclear membrane is partial or totally responsible of the repressed template activity of human sperm nucleus has not at present been elucidated. One of the membrane-bound enzymatic activities which is concerned with the mechanisms whereby substances are thought to cross cell membranes is adenosintriphosphatase (ATPase). This prompted its characterization and distribution by high resolution photogrammetry on isolated human sperm nuclei. Isolated human spermatozoa nuclei were obtained as previously described. ATPase activity was demonstrated by the method of Wachstein and Meisel modified by Marchesi and Palade. ATPase activity was identified as dense and irregularly distributed granules confined to the internal leaflet of the nuclear membrane. Within the nucleus the appearance of the reaction product occurs as homogenous and dense precipitates in the interchromatin space.


2020 ◽  
Vol 8 (2) ◽  
pp. 79-90
Author(s):  
Arjun Sharma ◽  
Pravir Kumar ◽  
Rashmi K. Ambasta

Background: Silencing of several genes is critical for cancer therapy. These genes may be apoptotic gene, cell proliferation gene, DNA synthesis gene, etc. The two subunits of Ribonucleotide Reductase (RR), RRM1 and RRM2, are critical for DNA synthesis. Hence, targeting the blockage of DNA synthesis at tumor site can be a smart mode of cancer therapy. Specific targeting of blockage of RRM2 is done effectively by SiRNA. The drawbacks of siRNA delivery in the body include the poor uptake by all kinds of cells, questionable stability under physiological condition, non-target effect and ability to trigger the immune response. These obstacles may be overcome by target delivery of siRNA at the tumor site. This review presents a holistic overview regarding the role of RRM2 in controlling cancer progression. The nanoparticles are more effective due to specific characteristics like cell membrane penetration capacity, less toxicity, etc. RRM2 have been found to be elevated in different types of cancer and identified as the prognostic and predictive marker of the disease. Reductase RRM1 and RRM2 regulate the protein and gene expression of E2F, which is critical for protein expression and progression of cell cycle and cancer. The knockdown of RRM2 leads to apoptosis via Bcl2 in cancer. Both Bcl2 and E2F are critical in the progression of cancer, hence a gene that can affect both in regulating DNA replication is essential for cancer therapy. Aim: The aim of the review is to identify the related gene whose silencing may inhibit cancer progression. Conclusion: In this review, we illuminate the critical link between RRM-E2F, RRM-Bcl2, RRM-HDAC for the therapy of cancer. Altogether, this review presents an overview of all types of SiRNA targeted for cancer therapy with special emphasis on RRM2 for controlling the tumor progression.


Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1083
Author(s):  
Adhirath Sikand ◽  
Malgorzata Jaszczur ◽  
Linda B. Bloom ◽  
Roger Woodgate ◽  
Michael M. Cox ◽  
...  

In the mid 1970s, Miroslav Radman and Evelyn Witkin proposed that Escherichia coli must encode a specialized error-prone DNA polymerase (pol) to account for the 100-fold increase in mutations accompanying induction of the SOS regulon. By the late 1980s, genetic studies showed that SOS mutagenesis required the presence of two “UV mutagenesis” genes, umuC and umuD, along with recA. Guided by the genetics, decades of biochemical studies have defined the predicted error-prone DNA polymerase as an activated complex of these three gene products, assembled as a mutasome, pol V Mut = UmuD’2C-RecA-ATP. Here, we explore the role of the β-sliding processivity clamp on the efficiency of pol V Mut-catalyzed DNA synthesis on undamaged DNA and during translesion DNA synthesis (TLS). Primer elongation efficiencies and TLS were strongly enhanced in the presence of β. The results suggest that β may have two stabilizing roles: its canonical role in tethering the pol at a primer-3’-terminus, and a possible second role in inhibiting pol V Mut’s ATPase to reduce the rate of mutasome-DNA dissociation. The identification of umuC, umuD, and recA homologs in numerous strains of pathogenic bacteria and plasmids will ensure the long and productive continuation of the genetic and biochemical journey initiated by Radman and Witkin.


Zygote ◽  
1997 ◽  
Vol 5 (3) ◽  
pp. 213-217 ◽  
Author(s):  
J. Fulka ◽  
N.L. First ◽  
C. Lee ◽  
J. Fulka ◽  
R.M. Moor

SummaryImmature mouse oocytes (germinal vesicle stage, GV), oocytes at different stages during maturation (prometaphase to anaphase I) and matured oocytes (metaphase II arrested) were cultured in 6-dimethylaminopurine (6-DMAP)-supplemented medium also containing bromodeoxyuridine for the assessment of DNA replication in these cells. Immature oocytes remained arrested at the GV stage and DNA replication was never detected in them. On the other hand, oocytes at the prometaphase to anaphase-telophase I stages responded to 6-DMAP treatment by forming nuclei which synthesised DNA. Mature (metaphase II) oocytes did not respond to 6-DMAP and their chromatin remained condensed. DNA synthesis could even be induced in GV-staged oocytes, but only when they were fused to freshly activated oocytes and incubated in 6-DMAP-supplemented medium.


Nature ◽  
1976 ◽  
Vol 262 (5571) ◽  
pp. 805-807 ◽  
Author(s):  
L. C. PADHY ◽  
S. K. KAR ◽  
K. K. RAO ◽  
M. R. DAS

1987 ◽  
Vol 7 (10) ◽  
pp. 3554-3560
Author(s):  
F Cavalieri ◽  
M Goldfarb

Induction of quiescent BALB/c 3T3 murine fibroblasts by platelet-derived growth factor (PDGF) or fibroblast growth factor (FGFs) is accompanied by induction of c-myc gene expression. To study the role of c-myc in cell growth, we transfected BALB/c 3T3 cells with a plasmid construct containing a glucocorticoid-inducible c-myc gene. When these transfected cells were growth arrested in PDGF-FGF-freedefined medium, glucocorticoid treatment induced S-phase DNA synthesis. This induction of DNA synthesis was inefficient, and cell proliferation was not evident, suggesting that growth factors act through stimulation of c-myc expression together with other intracellular events.


1996 ◽  
Vol 80 (4) ◽  
pp. 1322-1330 ◽  
Author(s):  
M. Longphre ◽  
L. Y. Zhang ◽  
J. R. Harkema ◽  
S. R. Kleeberger

Ozone (O3) exposure produces inflammation in the airways of humans and animal models. However, the mechanism by which O3 affects these changes is uncertain. Mast cells are strategically located below the epithelium of the airways and are capable of releasing a number of proinflammatory mediators. We tested the hypothesis that mast cells contribute to inflammation, epithelial sloughing, and epithelial proliferation in the nasal and terminal bronchiolar murine airways after O3 exposure. Mast cell-sufficient (+/+), mast cell-deficient (W/Wv), and mast cell-repleted [bone marrow-transplanted (BMT) W/Wv] mice were exposed to 2 ppm O3 or filtered air for 3 h. Nasal and bronchoalveolar lavage fluids were collected 6 and 24 h after exposure. Differential cell counts and protein content of the lavage fluids were used as indicators of inflammation and permeability changes in the airways. O3-induced epithelial injury was assessed by light microscopy, and O3-induced DNA synthesis in airway epithelium was estimated by using a 5-bromo-2′-deoxyuridine-labeling index in the nasal and terminal bronchiolar epithelia. Relative to air control mice, O3 caused significant increases in inflammation, epithelial injury, and epithelial DNA synthesis in +/+ mice. There was no significant effect of O3 exposure on any measured parameter in the W/Wv mice. To further assess the role of mast cells in O3-induced epithelial damage, mast cells were restored in W/Wv mice by BMT from +/+ congeners. Relative to sham-transplanted W/Wv mice, O3 caused significant increases in epithelial damage and DNA synthesis as well as inflammatory indicators in BMT W/Wv mice. These observations are consistent with the hypothesis that mast cells significantly modulate the inflammatory and proliferative responses of the murine airways to O3.


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