The aim of this study was to analyze the relationship between oocyte diameter, meiotic and embryo developmental competence and the expression of the catalytic subunit of MPF, the p34cdc2, at mRNA, RNA and protein level, as well as its kinase activity, in prepubertal (1-2 months old) goat oocytes. MPF is the main meiotic regulator and a possible regulator of cytoplasmic maturation; therefore, it could be a key factor in understanding the differences between competent and incompetent oocytes. Oocytes were classified according to oocyte diameter in four categories: <110, 110-125, 125-135 and >135 μm and matured, fertilized and cultured in vitro. The p34cdc2 was analyzed in oocytes at the time of collection (0 h) and after 27 h of IVM (27 h) in each of the oocyte diameter categories. The oocyte diameter was positively related to the percentage of oocytes at MII after IVM (0, 20.7, 58 and 78%, respectively) and the percentage of blastocysts obtained at 8 days postinsemination (0, 0, 1.95 and 12.5%, respectively). The expression of RNA and mRNA p34cdc2 did not vary between oocyte diameters at 0 and 27 h. Protein expression of p34cdc2 increased in each oocyte category after 27 h of maturation. MPF activity among diameter groups did not vary at 0 h but after IVM there was a clear and statistically significant increase of MPF activity in the biggest oocytes. © 2006 Elsevier Inc. All rights reserved.
|Publication status||Published - 1 Feb 2007|
- Oocyte diameter