老化
MAPK/ERK通路
蛋白激酶A
卵母细胞
体外成熟
男科
磷酸化
化学
环己酰亚胺
脱磷
碎片(计算)
细胞生物学
生物
分子生物学
胚胎
蛋白质生物合成
医学
遗传学
磷酸酶
生态学
作者
S. Ebeling,Anina Labudda,B. Meinecke
标识
DOI:10.1111/j.1439-0531.2010.01588.x
摘要
Contents The role of mitogen‐activated protein kinase (MAPK) was investigated during ageing of porcine oocytes following in vitro maturation (IVM). Oocytes exhibiting an extruded first polar body after IVM for 46 h (79.3% metaphase II, M II) were used for the experiments. Nuclear maturation stages were not visibly altered after a further 12 h of ageing. Proportion of M II stages (42.9%) decreased significantly whereas fragmentation and degeneration of oocytes increased after an ageing time of 26 h. In vitro ageing for 12 and 26 h led to a significant reduction of MAPK phosphorylation (i.e. activation) compared to oocytes matured for 46 h. When MAPK was inhibited by U0126 in M II oocytes, 30.9% (12 h) and 39.7% (26 h) of oocytes, respectively, left metaphase II arrest and proceeded to early anaphase II. Pronuclear stages or fragmentation could be observed only sporadically (2.6–3.6%). After parthenogenetic activation of oocytes by ethanol/cycloheximide, cleavage stages were reached with rates of 51.9% (46 h IVM), 42.0% (12 h ageing) and 40.3% (26 h ageing), respectively. Furthermore, a significant higher proportion of long‐term aged oocytes (26 h) showed pronuclear formation (8.6%) and fragmentation (7.9%) compared to non‐aged oocytes (each 1.9%). It is concluded that both MAPK phosphorylation and cleavage rate after parthenogenetic activation decreased before alterations of nuclear stages could be detected during in vitro ageing of M II oocytes. A premature MAPK dephosphorylation of M II oocytes caused early anaphase II stages, but cleaved stages could not be achieved.
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