Parthenogenetic activation of bovine oocytes using bovine and murine phospholipase C zeta

Ross, Pablo J.; Beyhan, Zeki; Iager, Amy E.; Yoon, Sook‐Young; Malcuit, Christopher; Schellander, K.; Fissore, Rafael A.; Cibelli, José B.

doi:10.1186/1471-213x-8-16

Cited by 75 publications

(77 citation statements)

References 50 publications

(67 reference statements)

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“…Since induction of 240 abnormally high frequent and/or prolonged calcium elevation may trigger premature termination of embryonic development [36], the additional activation stimuli better to mimic the mechanism induced during normal fertilization without affecting other oocytes metabolic pathway. Ooplasmic injection of a promising SOAF candidate, phospholipase C zeta or its cRNA [37] was applied as a more physiological approach, but complicated steps required for isolation of this substance or 245 preparation of its cRNA as well as difficulty to control the injected volumes make this method far from practical.…”

Section: Discussionmentioning

confidence: 99%

A combined treatment of ionomycin with ethanol improves blastocyst development of bovine oocytes harvested from stored ovaries and microinjected with spermatozoa

et al. 2009

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Regardless of the presence of sperm-borne oocyte-activating factors, activation of bovine oocytes with exogenous activation stimuli is required for further development after intracytoplasmic sperm injection (ICSI). The present study was designed to develop a new activation regimen for improving the blastocyst yield after ICSI of bovine oocytes harvested from ovaries stored at 10-12 oC for 24 h. Following ICSI, oocytes were treated with 5 μM ionomycin for 5 min, 7% ethanol for 5 or 10 min, ionomycin followed by ethanol (5 or 10 min), ionomycin followed by 10 µg/mL Cycloheximide for 5 h, or ionomycin followed by 1.9 mM 6-dimethylaminopurine for 3 h. Across the activation regimens, the cleavage rates of ICSI oocytes (45-77%) were higher than those of parthenogenetically activated oocytes (11-21%; P<0.05). Activating the ICSI oocytes with ionomycin plus ethanol improved the blastocyst yield (29-30%) comparing to the non-treated oocytes (12%; P<0.05) but the other regimens did not (9-18%; P>0.05). The higher blastocyst yields were due to increasing the proportion of ICSI oocytes that passed through the early postfertilization events until cleavage. None of the regimens have any adverse effect on the quality of the blastocysts regarding the total cell number or the proportion of the inner cell mass cells. Thus, a new activation regimen composed from two triggers for single calcium increase has been proven effective to improve the blastocyst yield after bovine ICSI using oocytes harvested from stored ovaries.Dear Dr. John P. Kastelic, Thank you very much for prompt reply and accepting our manuscript for publication in Theriogenology. We have replied for each comment from Co-editor and the reviewer-2 in pointby-point basis.Sincerely yours, Shinichi Hochi (Corresponding author)Hany Abdalla (First author)Co-editor 1-P value has been added to the Abstract (Lines 27,29).2-The number of the references in Introduction section has been reduced. Reviewer #21-Regarding omitting the two groups (5 min ethanol group and ionomycin followed by 5 min ethanol group); We do not think that the presence of these two groups causes any difficulty to recognize the superiority of ionomycin and ethanol combination. Since activation of 7% ethanol for 5 min 4 hr after ICSI is a commonly applied method for bovine ICSI, presence of such group must be important to declare the superiority of the new combination (ionomycin and ethanol) over the methods of ethanol alone under the same experimental circumstance regarding oocyte quality, injection skill, culture condition, and so on. For the ionomycin followed by 5 min ethanol, the efficiency of this method to improve the cleavage and the blastocyst yield was similar to that of ionomycin followed by 10 min ethanol, making it possible to choose the method in which oocytes are exposed to minimum exogenous stimuli. Tables 1 and 2. 2-The time of 2 nd polar body detection has been added in footnote of 15Running head: Bovine oocyte activation after ICSI * Manuscript 2 AbstractRegardless of the pres...

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Section: Discussionmentioning

confidence: 99%

A combined treatment of ionomycin with ethanol improves blastocyst development of bovine oocytes harvested from stored ovaries and microinjected with spermatozoa

et al. 2009

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“…We have previously shown that PLCZ cRNA injection into bovine oocytes was able to induce long-lasting [Ca 2C ] i oscillations and IP 3 R-1 downregulation and that it supported high rates of parthenogenetic development to the blastocyst stage (Malcuit et al 2006b, Ross et al 2008b. In the present study, we compared in vitro development, gene expression patterns, and epigenetic modifications in SCNT embryos activated by PLCZ cRNA injection with embryos activated by chemical methods or produced by IVF.…”

Section: Introductionmentioning

confidence: 99%

Activation of bovine somatic cell nuclear transfer embryos by PLCZ cRNA injection

Ross¹,

Rodríguez²,

Iager³

et al. 2009

Reproduction

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The production of cloned animals by the transfer of a differentiated somatic cell into an enucleated oocyte circumvents fertilization. During fertilization, the sperm delivers a sperm-specific phospholipase C (PLCZ) that is responsible for triggering Ca 2C oscillations and oocyte activation. During bovine somatic cell nuclear transfer (SCNT), oocyte activation is artificially achieved by combined chemical treatments that induce a monotonic rise in intracellular Ca 2C and inhibit either phosphorylation or protein synthesis. In this study, we tested the hypothesis that activation of bovine nuclear transfer embryos by PLCZ improves nuclear reprogramming. Injection of PLCZ cRNA into bovine SCNTunits induced Ca 2C oscillations similar to those observed after fertilization and supported high rates of blastocyst development similar to that seen in embryos produced by IVF. Furthermore, gene expression analysis at the eight-cell and blastocyst stages revealed a similar expression pattern for a number of genes in both groups of embryos. Lastly, levels of trimethylated lysine 27 at histone H3 in blastocysts were higher in bovine nuclear transfer embryos activated using cycloheximide and 6-dimethylaminopurine (DMAP) than in those activated using PLCZ or derived from IVF. These results demonstrate that exogenous PLCZ can be used to activate bovine SCNT-derived embryos and support the hypothesis that a fertilization-like activation response can enhance some aspects of nuclear reprogramming.

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“…Our results showed that JMJD3 is translated to protein soon after fertilization and persists, with oscillations, until the blastocyst stage. This expression pattern corresponds in time and cellular location with the decrease of H3K27me3 in preimplantation embryos (36).…”

Section: Expression and Localization Of Jmjd3 Protein In Preimplantationmentioning

confidence: 99%

Jumonji domain-containing protein 3 regulates histone 3 lysine 27 methylation during bovine preimplantation development

Cánovas

Cibelli

Ross

2012

Proc. Natl. Acad. Sci. U.S.A.

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Understanding the mechanisms of epigenetic remodeling that follow fertilization is a fundamental step toward understanding the bases of early embryonic development and pluripotency. Extensive and dynamic chromatin remodeling is observed after fertilization, including DNA methylation and histone modifications. These changes underlie the transition from gametic to embryonic chromatin and are thought to facilitate embryonic genome activation. In particular, trimethylation of histone 3 lysine 27 (H3K27me3) is associated with gene-specific transcription repression. Global levels of this epigenetic mark are high in oocyte chromatin and decrease to minimal levels at the time of embryonic genome activation. We provide evidence that the decrease in H3K27me3 observed during early development is cell-cycle independent, suggesting an active mechanism for removal of this epigenetic mark. Among H3K27me3-specific demethylases, Jumonji domain-containing protein 3 (JMJD3), but not ubiquitously transcribed tetratricopeptide repeat X (UTX), present high transcript levels in oocytes. Soon after fertilization JMJD3 protein levels increase, concurrent with a decrease in mRNA levels. This pattern of expression suggests maternal inheritance of JMJD3. Knockdown of JMJD3 by siRNA injection in parthenogenetically activated metaphase II oocytes resulted in inhibition of the H3K27me3 decrease normally observed in preimplantation embryos. Moreover, knockdown of JMJD3 in oocytes reduced the rate of blastocyst development. Overall, these results indicate that JMJD3 is involved in active demethylation of H3K27me3 during early embryo development and that this mark plays an important role during the progression of embryos to blastocysts.G amete nuclei undergo extensive chromatin remodeling soon after fertilization, including alterations to DNA methylation levels and posttranslational histone tail modification. These changes are known to influence chromatin structure and transcriptional readout (1) and also to promote embryonic genome activation (EGA) (2), which occurs in humans and cows after three to four cell divisions (3-5). Because the first few cell divisions occur without embryonic gene transcription, maternally inherited mRNA and proteins present in the oocyte are likely responsible for inducing these epigenetic changes (6).Histone lysine methylation is involved in transcriptional repression and/or activation and plays a key role during lineage specification and cell differentiation (7). Di-and trimethylation of histone 3 lysine 27 (H3K27) are catalyzed by the polycomb repressive complex 2 (PRC2), which has three essential components: enhancer of zeste homolog 2 (EZH2), embryonic ectoderm development (EED), and suppressor of zeste 12 (SUZ12) (8-10). These epigenetic marks are specifically associated with gene repression (11) and are typical of many key developmental genes in embryonic stem cells, stem cell maintenance (12-14), and regulation of pluripotency (15). In mouse embryos, asymmetric distribution of trimethylated H3K27 (H3K27me3) i...

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Parthenogenetic activation of bovine oocytes using bovine and murine phospholipase C zeta

Cited by 75 publications

References 50 publications

A combined treatment of ionomycin with ethanol improves blastocyst development of bovine oocytes harvested from stored ovaries and microinjected with spermatozoa

A combined treatment of ionomycin with ethanol improves blastocyst development of bovine oocytes harvested from stored ovaries and microinjected with spermatozoa

Activation of bovine somatic cell nuclear transfer embryos by PLCZ cRNA injection

Jumonji domain-containing protein 3 regulates histone 3 lysine 27 methylation during bovine preimplantation development

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