Differential effects of protein synthesis inhibitors on porcine oocyte activation

Nussbaum, Diana J.; Prather, Randall S.

doi:10.1002/mrd.1080410111

Cited by 66 publications

(53 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The inhibitory studies revealed that in our in vitro oocyte model, de novo transcription is not required for activation of cytoplasmic fragmentation; however, de novo protein production was mandatory as treatment with CHX completely abrogated induction of cytoplasmic fragmentation. As it has been previously determined that CHX becomes ineffective during later time points of treatment, 27 it is likely that proteins required for the activation of fragmentation are synthesized within the early stages of exposure to DXR. This is consistent with our observation that 4 h of minimum exposure to DXR is required before commitment to death pathways.…”

Section: Discussionmentioning

confidence: 99%

Molecular requirements for doxorubicin-mediated death in murine oocytes

Jurisicova

et al. 2006

Cell Death Differ

View full text Add to dashboard Cite

We previously published evidence that oocytes exposed to doxorubicin (DXR), a widely used chemotherapeutic agent, rapidly undergo morphological and biochemical changes via discrete effector signaling pathways consistent with the occurrence of apoptosis. In this report, we elucidated the molecular requirements for actions of this drug in oocytes. Our results indicate that within 1 h of exposure DXR causes rapid DNA damage, and commits the oocyte to cytoplasmic fragmentation by the fourth hour, followed by delayed oocyte activation and execution of cytoplasmic fragmentation. Inhibitors that interfere with oocyte activation consistently rescue cytoplasmic fragmentation, but fail to suppress DNA damage. There was evidence of depletion of Bax, Caspase-2, MA-3 and Bcl-x transcripts, suggesting that modulations by DXR caused recruitment of these maternal transcripts into the translation process. Furthermore, sphingolipids such as sphingosine-1-phosphate and ceramide modulate DXR actions by, respectively, altering its intracellular trafficking, or by sustaining the drug's contact with DNA.

show abstract

Section: Discussionmentioning

confidence: 99%

Molecular requirements for doxorubicin-mediated death in murine oocytes

Jurisicova

et al. 2006

Cell Death Differ

View full text Add to dashboard Cite

show abstract

“…In pig and cattle oocytes, cycloheximide treatment alone failed to induce activation as effectively as stimuli that generated an intracellular calcium rise [132,148,149]. However, when used in combination with ethanol or electric pulses, cycloheximide treatment increased the percentage of oocytes that formed pronuclei and cleaved [132,148,149,161].…”

Section: Protein Synthesis Inhibitorsmentioning

confidence: 99%

Calcium Release at Fertilization: Artificially Mimicking the Oocyte's Response to Sperm.

Grupen¹,

Nottle²,

Nagashima

2002

Journal of Reproduction and Development

View full text Add to dashboard Cite

Abstract. The mechanism of sperm-induced calcium release has been the subject of many studies since the development in the late 1950s of in vitro culture systems that support mammalian fertilization. Despite efforts to elucidate the nature of the signal from the sperm that triggers both the early and late events of oocyte activation, the precise mechanism remains unresolved. Now, with the advent of somatic nuclear transfer technologies, the need to better understand this unique process has been recognised. Nuclear transfer embryos must be induced to commence development artificially because the activating signal from the sperm is absent. The primary activating stimulus is a large increase in the concentration of intracellular-free calcium and numerous physical and chemical treatments have been found to induce calcium changes that initiate the events of oocyte activation. Although live cloned offspring have been produced in a number of species, the overall efficiencies of the nuclear transfer procedures described thus far are unacceptably low and phenotypic anomalies are common. With the aim of improving these efficiencies, researchers are developing artificial activation treatments which induce oocyte responses that mimic those induced by fertilizing sperm. One strategy is to replicate the pattern of calcium change more closely. Another strategy is to couple an activating stimulus with treatments that inhibit maturation (or M-phase) promoting factor (MPF) activity, which regulates meiotic progression in oocytes. This paper reviews what is understood of calcium release at fertilization and describes the treatments that have been used to induce oocyte activation artificially in parthenogenetic and nuclear transfer studies. The relative effectiveness of the strategies employed to mimic the oocyte's response to sperm are discussed. Key words: Oocyte activation, Fertilization, Parthenogenesis, Nuclear transfer (J. Reprod. Dev. 48: 2002) o produce a viable embryo at fertilization, the s p e r m n o t o n l y p r o v i d e s t h e m a l e chromosomal complement, but also the stimulus that initiates development. The mechanism by which the activating signal is transmitted from the sperm to the oocyte is not fully clarified, but it is clear that this signal triggers a large increase in the concentration of intracellular-free calcium. In fertilized sea urchin and Xenopus eggs, the calcium increase takes the form of a propagating wave that originates at the point of sperm attachment and traverses the egg at a velocity of 5 to 10 µm/sec

show abstract

“…Studies on uniparental embryos, such as gynogenotes, androgenotes, and parthenotes, are essential to our understanding of genome imprinting. Porcine parthenotes can be obtained by electrical stimulation of metaphase-II (M-II) oocytes (Hagen et al 1991, Prather et al 1991, Lee et al 2004, by the treatment with chemicals, such as ionophores (Hagen et al 1991, Wang et al 1998, or by a combination of electrical activation and treatment with chemicals, such as protein synthesis inhibitors (Nussbaum & Prather 1995), or protein kinase inhibitors (Dinnyes et al 1999). The most effective and widely used method of activating oocytes is electrical stimulation.…”

Section: Introductionmentioning

confidence: 99%

Diploid porcine parthenotes produced by inhibition of first polar body extrusion during in vitro maturation of follicular oocytes

Somfai

Ozawa²,

Noguchi³

et al. 2006

Reproduction

View full text Add to dashboard Cite

We investigated nuclear progression and in vitro embryonic development after parthenogenetic activation of porcine oocytes exposed to cytochalasin B (CB) during in vitro maturation (IVM). Nuclear progression was similar in control oocytes and oocytes matured in the presence of 1 mg/ml CB (IVM-CB group) by 37 h IVM; at this time the proportion of oocytes that had reached or passed through the anaphase-I stage did not differ significantly between the IVM-CB and the control groups (61.3 and 69.9% respectively; P!0.05). After IVM for 37 h, no polar body extrusion was observed in the IVM-CB group. In these oocytes, the two lumps of homologous chromosomes remained in the ooplasm after their segregation and turned into two irregular sets of condensed chromosomes. By 41 h IVM, the double sets of chromosomes had reunited in 89.5% IVM-CB oocytes and formed a single large metaphase plate, whereas 68.8% of the control oocytes had reached the metaphase-II stage by this time. When IVM-CB oocytes cultured for 46 h were stimulated with an electrical pulse and subsequently cultured for 8 h without CB, 39.0% of them extruded a polar body and 82.9% of them had a female pronucleus. Chromosome analysis revealed that the majority of oocytes that extruded a polar body were diploid in both the control and the IVM-CB groups. However, the incidence of polyploidy in the IVM-CB group was higher than that in the control group (P!0.05). In vitro development of diploid parthenotes in the control and the IVM-CB groups was similar in terms of blastocyst formation rates (45.8 and 42.8% respectively), number of blastomeres (39.9 and 44.4 respectively), the percentage of dead cells (4.3 and 2.9% respectively), and the frequency of apoptotic cells (7.3 and 6.3% respectively). Tetraploid embryos had a lower blastocyst formation rate (25.5%) and number of cells (26.2); however, the proportion of apoptotic nuclei (7.0%) was similar to that in diploid parthenotes. These results suggest that the proportion of homozygous and heterozygous genes does not affect in vitro embryo development to the blastocyst stage.

show abstract

Differential effects of protein synthesis inhibitors on porcine oocyte activation

Cited by 66 publications

References 14 publications

Molecular requirements for doxorubicin-mediated death in murine oocytes

Molecular requirements for doxorubicin-mediated death in murine oocytes

Calcium Release at Fertilization: Artificially Mimicking the Oocyte's Response to Sperm.

Diploid porcine parthenotes produced by inhibition of first polar body extrusion during in vitro maturation of follicular oocytes

Contact Info

Product

Resources

About