Abstract：Aurora-B is a serine/threonine protein kinase which plays important regulatory role during mitotic cell cycle progression, but its expression, localization and functionality during mammalian oocyte meiosis are seldom reported, and no related reports in pigs (Sus scrofa). In the present experiment, Aurora-B expression, subcellular localization, and its possible function during porcine oocyte meiotic maturation were investigated via confocal microscopic analysis and highly selective Aurora-B inhibitor treatment. Confocal microscopic analysis revealed that Aurora-B distributed uniformly in the cytoplasm at germinal vesicle(GV) stage. After germinal vesicle breakdown, Aurora-B expression was mainly associated with chromosomal. During MⅠ period, with spindle assembly and sister chromatids were arranged in the equatorial plate, Aurora-B overlaped with chromatin. In AITI , chromosomes began to migrate to the poles under the spindle traction, then Aurora-B located in the centre of chromosomes, but not overlaped with sister chromatids. Oocytes discharged the first polar body(pbI) after 44 hours when Aurora-B enriched on the oocyte nucleus and pbI. After using inhibitors AZD-1152 treatment, the results showed that more and more oocytes arrested in GV stage with the increasing concentrations of AZD-1152, GVBD incidence suppressed; compared with control group, the oocytes arrested in Pro MⅠ-AITI were significantly increased (P<0.05), arrested in MⅡ were significantly reduced(P<0.05). At the same time, MⅡ oocyte chromosome misaligned, some failed to align; abnormal spindle morphology, even disappeared; actin filaments had a certain degree of fracture and dispersion. In addition, porcine parthenogenetic embryos development severely affected after suppressing the expression of Aurora-B by inhibitor on oocytes. Cleavage rate, blastocyst rate and the total number of blastocyst cells are significantly lower with the increasing concentrations of AZD-1152 in each treatment group, and no blastocyst when the AZD-1152 concentration reached 50 nmol/L. Our study showed that Aurora-B may be a multifunctional kinase that plays pivotal regulatory roles in microtubule assembly, chromosome segregation during porcine oocyte meiotic maturation, and also plays a role in the subsequent development of oocytes.
