ve a role in mitotic cell division MedChemExpress BioPQQ during plant growth. Further analysis of coordinated mechanisms involving Haspin and Aurora kinases will shed new light on the regulation of chromosome segregation in cell division during plant growth and development. Background The mitotic phase, which comprises mitosis and cytokinesis, is a fundamental process for faithful transmission of genetic information from one cell generation to the next. The main purpose of mitosis is to segregate sister chromatids into two daughter cells. The regulation of mitotic progression relies mainly on two post-translational mechanisms; protein phosphorylation and proteolysis. Cell division is regulated by mitotic kinases, such as the cyclin-dependent kinase 1, the Polo family, the NIMA, and the Aurora family, as well as kinases implicated in mitotic checkpoints, mitotic exit and cytokinesis. Correspondence: [email protected]; [email protected] 3 Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan Full list of author information is available at the end of the article Post-translational modifications of core histones play a crucial role in chromatin structure and gene expression. Although the N-terminal sequence and phosphorylations of histone H3 are highly conserved among eukaryotes, the distribution patterns of phosphorylated histone H3 on the chromosomes differ between animals and plants. In mammalian cells, H3S10ph begins to appear in pericentromeric regions from G2 phase, spreading along the chromosome periphery until metaphase, and then disappearing at late anaphase. The phosphorylation pattern of H3S28 is similar to that of H3S10ph during mitosis. Because the spatial and temporal patterns of H3S10ph and H3S28ph are consistent with chromosome condensation and decondensation, it is thought that H3S10ph and H3S28ph have a crucial role in chromosome condensation in animals. In contrast, H3S10ph and H3S28ph occur in the pericentromeric regionsnot 2011 Kurihara et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Kurihara et al. BMC Plant Biology 2011, 11:73 http://www.biomedcentral.com/1471-2229/11/73 Page 2 of 14 along the whole chromosomefrom prophase to anaphase in plants. These distribution patterns suggest that H3S10ph and H3S28ph play a crucial role in cohesion and segregation of sister chromatids. In plants, AtAUR3 phosphorylates histone H3 at Ser10 and Ser28 in vitro. Inhibition of Aurora kinase by Hesperadin treatment prevents H3S10ph and H3S28ph in tobacco BY-2 cells and H3S10ph in Arabidopsis suspension cells. Thus, Aurora kinases phosphorylate histone H3 at Ser10 and Ser28 in plants. H3T3 and H3T11 are also phosphorylated, but their distribution patterns differ from those of H3S10ph and H3S28ph during mitosis. In mammalian cells, H3T3ph and H3T11ph occur preferentially at the centromere from prophase to anaphase. In contrast, H3T3ph and H3T11ph are distributed PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19797228 along the entire length of the chromosome in plants. Aurora kinases phosphorylate histone H3 at Ser10 and Ser28, but the kinase responsible for H3T3ph and H3T11ph is yet to be identified in plants. Haspin was first identified as a testis-specific gene in mice. Although Haspin mRNA levels were highest in the tes