摘要
Coordination of cell division and cell fate is crucial for the successful development of mammalian early embryos. Aurora kinases are evolutionarily conserved serine/threonine kinases and key regulators of mitosis. Aurora kinase B （AurkB） is ubiquitously expressed while Aurora kinase C （AurkC） is specifically expressed in gametes and preimplantation embryos. We found that increasing AurkC level in one blastomere of the 2-cell embryo accelerated cell division and decreasing AurkC level slowed down mitosis. Changing AurkB level had the opposite effect. The kinase domains of AurkB and AurkC were responsible for their different ability to phosphorylate Histone H3 Serine 10 （H3S10P） and regulate metaphase timing. Using an Oct4-photoactivat- able GFP fusion protein （Oct4-paGFP） and fluorescence decay after photoactivation assay, we found that AurkB overexpression reduced Oct4 retention in the nucleus. Finally, we show that blastomeres with higher AurkC level elevated pluripotency gene expression, which were inclined to enter the inner cell mass lineage and subsequently contributed to the embryo proper. Collectively, our results are the first demonstration that the activity of mitotic kinases can influence cell fate decisions in mammalian preimplantation embryos and have important implications to assisted reproduction.
Coordination of cell division and cell fate is crucial for the successful development of mammalian early embryos. Aurora kinases are evolutionarily conserved serine/threonine kinases and key regulators of mitosis. Aurora kinase B （AurkB） is ubiquitously expressed while Aurora kinase C （AurkC） is specifically expressed in gametes and preimplantation embryos. We found that increasing AurkC level in one blastomere of the 2-cell embryo accelerated cell division and decreasing AurkC level slowed down mitosis. Changing AurkB level had the opposite effect. The kinase domains of AurkB and AurkC were responsible for their different ability to phosphorylate Histone H3 Serine 10 （H3S10P） and regulate metaphase timing. Using an Oct4-photoactivat- able GFP fusion protein （Oct4-paGFP） and fluorescence decay after photoactivation assay, we found that AurkB overexpression reduced Oct4 retention in the nucleus. Finally, we show that blastomeres with higher AurkC level elevated pluripotency gene expression, which were inclined to enter the inner cell mass lineage and subsequently contributed to the embryo proper. Collectively, our results are the first demonstration that the activity of mitotic kinases can influence cell fate decisions in mammalian preimplantation embryos and have important implications to assisted reproduction.
基金
ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China （Grant No. 31171381）, NSFC-MRC China-UK collaborative project grant 81261130320, the Beijing Natural Science Foundation grant 20151100084 （J.N.）, the National Basic Research Program （973 Program） （Nos. 2016YFC0900301 and 2015CB856201 ）, the Youth Thousand Scholar Program of China （W.X.）, and the funding from the Tsinghua-Peking Center for Life Sciences （W.X., J.N.）. We thank the animal facility, SLSTH-Nikon Biological Imaging Center of Tsinghua University for assistance with fluorescence imaging and Dr. Richard de Grijs for helpful comments and English language editing of the manuscript. All authors have contributed to, read, and approved the manuscript for submission.
