Involvement of Polo-like kinase 1 in MEK1/2-regulated spindle formation during mouse oocyte meiosis.

Our recent studies have shown that MEK1/2 is a critical regulator of microtubule organization and spindle formation during oocyte meiosis. In the present study, we found that Plk1 colocalized with p-MEK1/2 at various meiotic stages after GVBD when microtubule began to organize. Also, Plk1 was able to coimmunoprecipitate with p-MEK1/2 in metaphase I stage mouse oocyte extracts, further confirming their physical interaction.

The spatial relationship between heterochromatin protein 1 alpha and histone modifications during mouse oocyte meiosis.

Heterochromatin protein 1 (HP1) is closely associated with diverse chromatin organization and function in mitosis. However, we almost know nothing about HP1 in mammalian oocyte. Here, we investigated the subcellular distribution of HP1alpha and its spatial relationship to histone modifications during mouse oocyte maturation.

Regulation of intracellular MEK1/2 translocation in mouse oocytes: cytoplasmic dynein/dynactin-mediated poleward transport and cyclin B degradation-dependent release from spindle poles.

We recently reported that MEK1/2 plays an important role in microtubule organization and spindle pole tethering in mouse oocytes, but how the intracellular transport of this protein is regulated remains unknown. In the present study, we investigated the mechanisms of poleward MEK1/2 transport during the prometaphase I/metaphase I transition and MEK1/2 release from the spindle poles during the metaphase I/anaphase I transition in mouse oocytes. Firstly, we found that p-MEK1/2 was colocalized with dynactin at the spindle poles.

Histone deacetylation is required for orderly meiosis.

Histone acetylation is associated with a diversity of chromatin-related processes in mitosis. However, its roles in mammalian oocyte meiosis are largely unknown. In the present study, we first investigated in detail the acetylation changes during porcine oocyte maturation using a panel of antibodies specific for the critical acetylated forms of histone H3 and H4, and showed meiosis stage-dependent and lysine residue-specific patterns of histone acetylation.

Effects of oocyte collection time and injection position on pronucleus formation and blastocyst development in round spermatid injection in mouse.

The injection of spermatozoa into mouse, human and rabbit oocytes at specific times and positions can result in different rates of viable embryo development. However, it is not clear how the timing and position of round spermatid injection (ROSI) affect pronucleus (PN) formation and blastocyst development of mice. First, we determined the changes in relative position of the first polar body and the spindle, carried out ROSI from 11.