In syncytial embryos and oocytes, entire mitotic/meiotic chromosomes are stained with the anti dH2ApT119 antibody. To verify the phosphorylation pattern present in S2 cells isn’t specific to the cell line, we reviewed H2A phosphorylation in somatic cells of developing flies. The larval central nervous system is the muscle most commonly used for the analysis of standard mitotic cell cycles, that have two gap phases and checkpoint regulation. Immunostaining of larval research chemicals library CNSs unmasked an identical temporal and spatial pattern of H2A T119 phosphorylation as present in S2 cells. Previously, the protein kinase NHK 1 was defined as phosphorylating H2A T119 in-vitro. Phosphorylation was greatly reduced by a female sterile mutation in NHK 1 here in oocytes, although not in string or nurse cells. This suggested that NHK 1 is the important kinase responsible for this phosphorylation at the least within the oocyte nucleus. We examined whether exhaustion of this kinase by RNA interference affects the phosphorylation, to check whether NHK 1 is responsible for this phosphorylation in S2 cells. Down regulation of NHK 1 in S2 cells didn’t get rid of the transmission of the phospho H2A antibody in immunostaining. This effect Infectious causes of cancer was further confirmed by immunostaining of larval CNSs from a null mutant of NHK 1. These results suggested that whether extra volume of NHK 1 kinase is enough to phosphorylate this site or kinases apart from NHK 1 could phosphorylate this site in the lack of NHK 1. To recognize the regulatory system of this change in H2A T119 phosphorylation, we first analyzed the potential role of Aurora B kinase which localises to the same centromeric area as the H2A phosphorylation. After Aurora B was reduced by RNAi, S-2 cells were immunostained with phospho H2A antibody. In Aurora W reduced cells, the intense centromeric staining in mitotic cells was paid down to levels comparable to that about the chromosome arms. Nevertheless, nuclear staining in interphase cells remained high, suggesting that the phosphorylation is controlled in interphase and mitosis by different systems. Aurora B kinase is a part of a minimum of two functionally distinct processes, a more substantial complex and a core complex. To know which complex is needed for the phosphorylation, we tried the element other subunits for the phosphorylation. Destruction of anyone of INCENP, Survivin and Borealin by RNAi considerably lowered H2A phosphorylation in centromeric regions in mitosis. Interphase phosphorylation was not affected in some of the circumstances. These results suggested the large AuroraB complex is required for centromeric phosphorylation of H2A at T119 in mitosis. To further study the regulatory mechanism of the phosphorylation, we examined the role of the important mitotic regulator Polo kinase.