Abstract
Chromosomal DNA in eukaryotes is wrapped around a histone octamer to form nucleosomes, the fundamental units of chromatin. Post-translational histone modification plays critical roles in regulating genome integrity, chromosome segregation, and gene expression. For example, DNA double strand breaks induce the modifications of histone H2AX, including acetylation, phosphorylation, and ubiquitylation. Phosphorylation of histone H3 is associated with chromosome condensation and segregation. The dynamics of such histone modifications have been analyzed using fixed or biochemically prepared samples so far. We now developed methods to visualize the dynamics of those modifications in living and permeabilized cells by using monoclonal antibodies. I will present here (1) visualizing the dynamics of histone H3 phosphorylation and chromosome missegregation in living cells using phospho-specific antibodies, and (2) detection of histone H2AX phosphorylation in permeabilized cells. These methods that allow the detection of protein modifications in situ will be useful for future studies on the radiation and chromosome biology.
