Fig. 3

FISH using ChIP-DNA and plastid DNA probes on sugar beet metaphase chromosomes Chromosomes were counterstained with DAPI (blue signals) revealing chromosome morphology. a and b Location of immunoprecipitated DNA is shown. Probes were labelled with digoxigenine and detected with antidigoxigenine coupled to FITC (green signals). a CenH3 ChIP-DNA probe detects centromeric regions. Bar = 5 μm. b H3K9me2 ChIP-DNA signals are distributed along the chromosome with stronger signals in the major intercalary heterochromatic region of each arm. Note, that signal strength is reduced in centromeric regions. Signals in centromeric regions are due to sequences occurring in association with both, CenH3 in the centromere and H3K9me2, e.g. sequences of Beetle4. The signals may be also due to the presence of H3K9me2 in active centromeres. Distal euchromatin shows depletion of signals. Bar = 5 μm. c Localization of plastid DNA on sugar beet chromosomes using a biotin dUTP-labelled plastid DNA probe detected by streptavidine-Cy3 (red signals). Plastid DNA sequences are found dispersed on all 18 chromosomes without restriction to particular chromosome regions. Bar = 5 μm