Base J originally found in Kinetoplastida is also a minor constituent of nuclear DNA of Euglena gracilis

We have analyzed DNA of Euglena gracilis for the presence of the unusual minor base β-d-glucosyl-hydroxymethyluracil or J, thus far only found in kinetoplastid flagellates and in Diplonema. Using antibodies specific for J and post-labeling of DNA digests followed by two-dimensional thin-layer chromatography of labeled nucleotides, we show that ~0.2 mole percent of Euglena DNA consists of J, an amount similar to that found in DNA of Trypanosoma brucei. By staining permeabilized Euglena cells with anti-J antibodies, we show that J is rather uniformly distributed in the Euglena nucleus, and does not co-localize to a substantial extent with (GGGTTA)(n) repeats, the putative telomeric repeats of Euglena. Hence, most of J in Euglena appears to be non-telomeric. Our results add to the existing evidence for a close phylogenetic relation between kinetoplastids and euglenids.