Trypanosoma cruzi rRNA genes: a repeated element from the non-transcribed spacer is locus specific.
To determine the occurrence of conserved domains of presumed functional selection, a genomic restriction analysis was carried out in the region surrounding a transcription start point (tsp) from the rRNA cistron in T. cruzi. The transcribed spacer was found highly conserved among several isolates, whereas at 146 bp upstream from the tsp a highly polymorphic pattern was evidenced with a probe that contains sequences of a repetitive element (172 bp). Both genomic and chromosomal hybridizations indicated the linkage of the repetitive element to coding regions of the rRNA cistron. This represents the first example of a repetitive element not interspersed throughout the genome of T. cruzi, and strongly suggests that a functional role is being selected.
Pulido
M
M
Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México D.F., México.
Martínez-Calvillo
S
S
Hernández
R
R
D000818:Animals; D015139:Blotting, Southern; D015342:DNA Probes; D016054:DNA, Protozoan / Q000032:analysis / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics*; D008040:Genetic Linkage; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D012150:Polymorphism, Restriction Fragment Length; D012335:RNA, Ribosomal / Q000235:genetics*; D012091:Repetitive Sequences, Nucleic Acid; D015183:Restriction Mapping; D014158:Transcription, Genetic; D014349:Trypanosoma cruzi / Q000235:genetics*
D015342:DNA Probes; D016054:DNA, Protozoan; D004275:DNA, Ribosomal; D012335:RNA, Ribosomal