Functional mapping of a trypanosome centromere by chromosome fragmentation identifies a 16-kb GC-rich transcriptional “strand-switch” domain as a major feature

Organization of the GC-rich strand-switch regions on T. cruzi chromosomes 1 (lower)and3(upper). Green arrows identify the first ORFs of the polycistronic gene clusters and indicate the direction of transcription. The degenerate retrotransposon-like VIPER/SIRE element (black) and the L1Tc autonomous retroelements (red) are indicated. This region of chromosome 3 also contains a truncated cruzipain pseudogene (czp) and a U2snRNA gene. In chromosome 1, the strand-switch domain is located ∼120 kb from the telomere, 70-kb upstream of the Tcsod locus (Fig. 2), between ORFs identified by temporary systematic-ids Tc00.1047053508707.234 and 270.