Aurora B kinase is required and sufficient to phosphorylate H3S10ph in 10T1/2 cell nuclei transplanted to germinal vesicles. (a) A Western blot of H3S10ph in nuclei incubated in buffer, oocyte extracts or in Aurora B immunodepleted oocyte extracts is shown. The quantitative analysis of these bands is shown below the Western blot; H3S10ph normalized to H3 in nuclei incubated in buffer is shown in blue, in oocyte extracts is shown in red and in nuclei in depleted extracts in yellow.(b) Aurora B immunodepletion from oocyte extracts. The level of Aurora B protein in Aurora B depleted oocyte extracts (lane 1), in non-depleted extracts (lane 2), in depleted Aurora B (lane3), or non-depleted Aurora B (lane 4) is shown. β-actin was also examined as a reference protein. The bar-chart shows the ratio of Aurora B:β-actin. (c) Aurora B protein can phosphorylate H3S10 in 10T1/2 nuclei. 10T1/2 nuclei were incubated with Aurora B protein for 1 h. H3S10ph is shown in red. 10T1/2 nuclei are stained with DAPI and shown in blue.