Effect of cyclin-dependent kinase (CDK) inhibition on expression, localization and activity of maturation promoting factor (MPF) and mitogen activated protein kinase (MAPK) in bovine oocytes.

This study aimed to assess the effects of cyclin-dependent kinase (CDK) inhibition on factors involved in the control of meiosis in bovine oocytes: maturation promoting factor (MPF) (p34(cdc2) and cyclin B1) and mitogen activated protein kinase (MAPK). Oocytes were maintained at germinal vesicle (GV) stage in vitro with 10 μM of the CDK inhibitor butyrolactone I (BLI) for 24 h (inhibited). After this period, some of the oocytes were transferred to in vitro maturation (IVM) culture for 24 h (inhibited and matured). Control oocytes were assessed immediately after follicle aspiration (immature) or after in vitro maturation for 24 h (matured). Real-time PCR analyses showed that transcripts for p34(cdc2) and MAPK were detected in immature and inhibited oocytes and decreased after maturation, irrespective of CDK inhibition with BLI. Cyclin B1 was detected at similar levels in all oocyte groups. The p34(cdc2) and MAPK proteins were detected by Western blotting at similar levels in all oocyte groups, and cyclin B1 protein was detected only after maturation. Immunofluorescence detection showed that p34(cdc2) was localized in the cytoplasm and GV of immature oocytes, and then throughout the cytoplasm after maturation. Cyclin B1 and MAPK were detected in the cytoplasm in all oocyte groups. Maturation promoting factor and MAPK activities were similar throughout most of maturation for oocytes treated with or without BLI. In conclusion, CDK inhibition did not affect the expression (mRNA and protein levels) and localization of MPF and MAPK, and had nearly no effect on kinase activities during maturation.

Quetglas MD ，Adona PR ，de Bem TH ，Pires PR ，Leal CL ... -  《-》

Gene expression in bovine oocytes and cumulus cells after meiotic inhibition with the cyclin-dependent kinase inhibitor butyrolactone I.

The aim of this study was to determine the effect of temporary inhibition of meiosis using the cyclin-dependent kinase inhibitor butyrolactone I (BLI) on gene expression in bovine oocytes and cumulus cells. Immature bovine cumulus-oocyte complexes (COCs) were assigned to groups: (i) Control COCs collected immediately after recovery from the ovary or (ii) after in vitro maturation (IVM) for 24 h, (iii) Inhibited COCs collected 24 h after incubation with 100 μm BLI or (iv) after meiotic inhibition for 24 h followed by IVM for a further 22 h. For mRNA relative abundance analysis, pools of 10 denuded oocytes and respective cumulus cells were collected. Transcripts related to cell cycle regulation and oocyte competence were evaluated in oocytes and cumulus cells by quantitative real-time PCR (qPCR). Most of the examined transcripts were downregulated (p < 0.05) after IVM in control and inhibited oocytes (19 of 35). Nine transcripts remained stable (p > 0.05) after IVM in control oocytes; only INHBA did not show this pattern in inhibited oocytes. Seven genes were upregulated after IVM in control oocytes (p < 0.05), and only PLAT, RBP1 and INHBB were not upregulated in inhibited oocytes after IVM. In cumulus cells, six genes were upregulated (p < 0.05) after IVM and eight were downregulated (p < 0.05). Cells from inhibited oocytes showed the same pattern of expression regarding maturation profile, but were affected by the temporary meiosis inhibition of the oocyte when the same maturation stages were compared between inhibited and control groups. In conclusion, changes in transcript abundance in oocytes and cumulus cells during maturation in vitro were mostly mirrored after meiotic inhibition followed by maturation.

Leal CL ，Mamo S ，Fair T ，Lonergan P ... -  《-》

Germinal vesicle material drives meiotic cell cycle of mouse oocyte through the 3'UTR-dependent control of cyclin B1 synthesis.

Hoffmann S ，Tsurumi C ，Kubiak JZ ，Polanski Z ... -  《DEVELOPMENTAL BIOLOGY》

Characterization of MPF and MAPK activities during meiotic maturation of Xenopus tropicalis oocytes.

Bodart JF ，Gutierrez DV ，Nebreda AR ，Buckner BD ，Resau JR ，Duesbery NS ... -  《DEVELOPMENTAL BIOLOGY》

Effect of oocyte diameter on meiotic competence, embryo development, p34 (cdc2) expression and MPF activity in prepubertal goat oocytes.

Anguita B ，Jimenez-Macedo AR ，Izquierdo D ，Mogas T ，Paramio MT ... -  《THERIOGENOLOGY》