Telomere terminating with centromere-specific repeats is closely associated with a transposon derived gene in...

We provide evidence that centromere-specific 155 bp DNA repeats terminate one pair of telomeres at the telocentric, left end of the short fourth chromosome in Chironomus pallidivittatus. Earlier evidence indicated that all other telomeres are terminated by 340 bp telomere-specific repeats. DNA that borders the 155 bp repeat contains a transcriptionally active 396 codon open reading frame (ORF) a few kilobases away from the repeat array. The conceptual product of the ORF has regions with similarities to transposase, DNA binding and endonuclease motifs and is likely to have an evolutionary origin in a transposon. It is flanked, within degenerate inverted repeats, by a modified form of an element, Cp80, that has previously been found to insert only into 155 bp repeats and that contains a putative CENP-B box and a region that is prone to recombine. The ORF may therefore have a functional relation to the centromeric region.