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Carrying-over effects of GVBD blocking on post-blocking meiotic progression of oocytes: species difference and the signaling pathway leading to MPF activation.

Jiao GZ, Lian HY, Gao Y, Sun MJ, Gong S, Zheng LL, Zhang CX, Tan JH - PLoS ONE (2014)

Bottom Line: Such knowledge is also important for studies aimed at regulating gene expression in maturing oocytes prior to GVBD.In both species, (a) whereas active CDC2A showed a dynamics similar to cyclin B, inactive CDC2A decreased continuously; (b) when oocytes were blocked in blocking medium containing cycloheximide, PBMP was decelerated significantly while cyclin B and active CDC2A decreasing to the lowest level; (c) whereas sodium vanadate in blocking medium reduced PBMP, epidermal growth factor (EGF) in blocking medium accelerated PBMP significantly with no effect on cyclin B levels.In conclusion, the EGF signaling cascade accelerated PBMP by promoting the pre-MPF (M-phase-promoting factor) to MPF conversion during GVBD blocking with roscovitine.

View Article: PubMed Central - PubMed

Affiliation: College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai-an City, P. R. China.

ABSTRACT
Efforts to improve the quality of in vitro matured oocytes by blocking germinal vesicle breakdown (GVBD) and allowing more time for ooplasmic maturation have achieved little due to a lack of knowledge on the molecular events during GVBD blocking. Such knowledge is also important for studies aimed at regulating gene expression in maturing oocytes prior to GVBD. We studied species difference and signaling pathways leading to the carrying-over effect of GVBD blocking on post-blocking meiotic progression (PBMP). Overall, GVBD-blocking with roscovitine decelerated PBMP of mouse oocytes but accelerated that of pig oocytes. During blocking culture, whereas cyclin B of pig oocytes increased continuously, that of mouse oocytes declined first and then increased slowly. In both species, (a) whereas active CDC2A showed a dynamics similar to cyclin B, inactive CDC2A decreased continuously; (b) when oocytes were blocked in blocking medium containing cycloheximide, PBMP was decelerated significantly while cyclin B and active CDC2A decreasing to the lowest level; (c) whereas sodium vanadate in blocking medium reduced PBMP, epidermal growth factor (EGF) in blocking medium accelerated PBMP significantly with no effect on cyclin B levels. In conclusion, the EGF signaling cascade accelerated PBMP by promoting the pre-MPF (M-phase-promoting factor) to MPF conversion during GVBD blocking with roscovitine. The significant difference in PBMP observed between mouse and pig oocytes was caused by species difference in cyclin B dynamics during blocking culture as no species difference was observed in either pre-MPF to MPF conversion or the EGF signaling activity.

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Nuclear progression of mouse oocytes following GVBD blocking for different times with roscovitine.Each treatment was repeated 3 times and each replicate contained some 20 oocytes. CX: Oocytes that had been blocked with roscovitine for 12 h were further treated for 12 h with roscovitine plus CHX to inhibit protein synthesis. a–e: Values without a common letter in their bars differ (P<0.05).
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pone-0103838-g001: Nuclear progression of mouse oocytes following GVBD blocking for different times with roscovitine.Each treatment was repeated 3 times and each replicate contained some 20 oocytes. CX: Oocytes that had been blocked with roscovitine for 12 h were further treated for 12 h with roscovitine plus CHX to inhibit protein synthesis. a–e: Values without a common letter in their bars differ (P<0.05).

Mentions: Mouse and pig oocytes were blocked in blocking medium before post-blocking culture with basic culture medium. Oocytes were examined for GVBD at different times of the post-blocking culture. Whereas the non-blocked mouse oocytes completed GVBD within 1.5 h, mouse oocytes blocked for 12, 24 and 36 h did not complete GVBD until 4.5, 2.5 and 2 h of post-blocking culture, respectively (Fig. 1). Whereas the non-blocked pig oocytes completed GVBD at 30 h, pig oocytes blocked for 12, 24 and 48 h completed GVBD at 24, 12 and 6 h of post-blocking culture, respectively (Fig. 2).


Carrying-over effects of GVBD blocking on post-blocking meiotic progression of oocytes: species difference and the signaling pathway leading to MPF activation.

Jiao GZ, Lian HY, Gao Y, Sun MJ, Gong S, Zheng LL, Zhang CX, Tan JH - PLoS ONE (2014)

Nuclear progression of mouse oocytes following GVBD blocking for different times with roscovitine.Each treatment was repeated 3 times and each replicate contained some 20 oocytes. CX: Oocytes that had been blocked with roscovitine for 12 h were further treated for 12 h with roscovitine plus CHX to inhibit protein synthesis. a–e: Values without a common letter in their bars differ (P<0.05).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4117542&req=5

pone-0103838-g001: Nuclear progression of mouse oocytes following GVBD blocking for different times with roscovitine.Each treatment was repeated 3 times and each replicate contained some 20 oocytes. CX: Oocytes that had been blocked with roscovitine for 12 h were further treated for 12 h with roscovitine plus CHX to inhibit protein synthesis. a–e: Values without a common letter in their bars differ (P<0.05).
Mentions: Mouse and pig oocytes were blocked in blocking medium before post-blocking culture with basic culture medium. Oocytes were examined for GVBD at different times of the post-blocking culture. Whereas the non-blocked mouse oocytes completed GVBD within 1.5 h, mouse oocytes blocked for 12, 24 and 36 h did not complete GVBD until 4.5, 2.5 and 2 h of post-blocking culture, respectively (Fig. 1). Whereas the non-blocked pig oocytes completed GVBD at 30 h, pig oocytes blocked for 12, 24 and 48 h completed GVBD at 24, 12 and 6 h of post-blocking culture, respectively (Fig. 2).

Bottom Line: Such knowledge is also important for studies aimed at regulating gene expression in maturing oocytes prior to GVBD.In both species, (a) whereas active CDC2A showed a dynamics similar to cyclin B, inactive CDC2A decreased continuously; (b) when oocytes were blocked in blocking medium containing cycloheximide, PBMP was decelerated significantly while cyclin B and active CDC2A decreasing to the lowest level; (c) whereas sodium vanadate in blocking medium reduced PBMP, epidermal growth factor (EGF) in blocking medium accelerated PBMP significantly with no effect on cyclin B levels.In conclusion, the EGF signaling cascade accelerated PBMP by promoting the pre-MPF (M-phase-promoting factor) to MPF conversion during GVBD blocking with roscovitine.

View Article: PubMed Central - PubMed

Affiliation: College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai-an City, P. R. China.

ABSTRACT
Efforts to improve the quality of in vitro matured oocytes by blocking germinal vesicle breakdown (GVBD) and allowing more time for ooplasmic maturation have achieved little due to a lack of knowledge on the molecular events during GVBD blocking. Such knowledge is also important for studies aimed at regulating gene expression in maturing oocytes prior to GVBD. We studied species difference and signaling pathways leading to the carrying-over effect of GVBD blocking on post-blocking meiotic progression (PBMP). Overall, GVBD-blocking with roscovitine decelerated PBMP of mouse oocytes but accelerated that of pig oocytes. During blocking culture, whereas cyclin B of pig oocytes increased continuously, that of mouse oocytes declined first and then increased slowly. In both species, (a) whereas active CDC2A showed a dynamics similar to cyclin B, inactive CDC2A decreased continuously; (b) when oocytes were blocked in blocking medium containing cycloheximide, PBMP was decelerated significantly while cyclin B and active CDC2A decreasing to the lowest level; (c) whereas sodium vanadate in blocking medium reduced PBMP, epidermal growth factor (EGF) in blocking medium accelerated PBMP significantly with no effect on cyclin B levels. In conclusion, the EGF signaling cascade accelerated PBMP by promoting the pre-MPF (M-phase-promoting factor) to MPF conversion during GVBD blocking with roscovitine. The significant difference in PBMP observed between mouse and pig oocytes was caused by species difference in cyclin B dynamics during blocking culture as no species difference was observed in either pre-MPF to MPF conversion or the EGF signaling activity.

Show MeSH
Related in: MedlinePlus