Identification of the telomeric sequence of the acellular slime molds Didymium iridis and Physarum polycephalum.

We have determined the telomeric DNA sequence of the acellular slime molds Didymium iridis and Physarum polycephalum. In both organisms the telomeres consist of tandem repeats of the hexamer 5'(TTAGGG)3'. This sequence was determined by cloning and sequencing the telomeric fragment of the linear extrachromosomal ribosomal DNA from Didymium, as well as direct end labeling and sequencing the rDNA from both organisms. Interestingly, this sequence is identical to the telomeric DNA sequence of the flagellated protozoan Trypanosoma brucei, and suggests that despite the diversity of telomeric sequences previously determined in lower eukaryotes, the necessity to create functional telomeres has led to constraints on these sequences.