Plk1 inhibition leads to a failure of mitotic division during the first mitotic division in pig embryos.

Abstract

This study was conducted to examine the dynamic distribution of polo-like 1 kinase (Plk1) and the possible role it plays in first mitotic division during early porcine embryo development. Indirect immunofluorescence and confocal microscopy imaging techniques combined with western blot analyses were used to study the dynamic expression and subcellular localization of Plk1 protein in pig parthenogenetic embryos. Finally, a selective Plk1 inhibitor, GSK461364, was used to evaluate the potential role of Plk1 during this special stage. The results showed that Plk1 upon expression exhibited specific dynamic intracellular localization, which closely correlated with the α-tubulin distribution during the first mitotic division. GSK461364 treatment resulted in cleavage failure, with majority of the GSK461364-treated embryos being arrested in prometaphase. Further results of the subcellular structure examination showed that GSK461364 treatment led to a significantly higher proportion of the treated embryos having abnormal spindles and misarranged chromosomes at the prometaphase stage. Thus, these results indicated that Plk1 is essential for porcine embryos to complete the first mitotic division. Furthermore, Plk1 regulation was associated with effects on spindle assembly and chromosome arrangement.