Dear Pedro, you may try indirect (or direct) immunofluorescence analysis by using phosphorylated antibodies against specific histones. Phosphorylation of histone H3 at S10 (H3phosphoS10) and histone H2A on T120 are mitotic markers. These modifications are involved in chromatin compaction and the regulation of chromatin structure and function during mitosis.
In fact we are already using Phospho Histone, but I was trying to find a substitute for the EdU. I am trying to get a hold on cells with their DNA replicating (S-phase cells).
Maybe you can try with antibodies against markers of cell-cycle such as cyclins. Indeed, cyclin A is generally used as a S phase marker in immunofluorescence experiments with cell cultures