Multiple histone H3 modifications are conserved in putatively early branching eukaryotes. Posttranslational histone H3 modifications (PTM) occur at conserved N-terminal sequence motifs (color shaded in A.) in Euglena gracilis as well as Trichomonas vaginalis as suggested by immunofluorescence (B.) and Western (C.) analyses. C-marked images represent peptide competition assays as antibody specificity control. Both species represent putatively early branching eukaryotic clades. In the immunofluorescence panel (B.) the various PTMs occur as green signals, whereas nuclei and in some cases other nucleic acid-containing structures occur as red signals. In some cases DNA containing structures where labelled as follows: micronucleus/during mitosis (m/m*), macronucleus (M), nucleus (n). Western analyses (C.) confirm that the antibody targeted to H3K4me3 reacts with a protein band similar in size to histone H3 in Euglena and Trichomonas. Even H3K9ac/K14ac was detected in both Euglena and Trichomonas.