Chromosome segregation requires that centromeres properly attach to spindle microtubules. This essential step regulates the accuracy of cell division and must therefore be precisely regulated. One of the main centromeric regulatory signaling pathways is the haspin-H3T3ph-chromosomal passenger complex (CPC) cascade, which is responsible for the recruitment of the CPC to the centromeres. During mitosis, the haspin kinase phosphorylates histone H3 at threonine 3 (H3T3ph), an essential epigenetic mark that recruits the CPC, in which the catalytic component is Aurora B kinase (AURKB). However, the centromeric haspin-H3T3ph-CPC pathway remains largely uncharacterized in mammalian male meiosis. We have analyzed haspin functions by either its chemical inhibition with LDN-192960 in cultured spermatocytes, or the ablation of the Haspin gene in Haspin-/- mice. Our studies suggest that haspin kinase activity is required for proper chromosome congression both during meiotic divisions and for the recruitment of Aurora B and kinesin MCAK (also known as KIF2C) to meiotic centromeres. However, the absence of H3T3ph histone mark does not alter borealin (or CDCA8) and SGO2 centromeric localization. These results add new and relevant information regarding the regulation of the haspin-H3T3ph-CPC pathway and centromere function during meiosis.
Keywords: Aurora B; Centromere; Centrosome; H3T3ph; Haspin; Meiosis.
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