Intergenic and external transcribed spacers of ribosomal RNA genes in lizard-infecting Leishmania: molecular structure and phylogenetic relationship to mammal-infecting Leishmania in the subgenus Leishmania (Leishmania)

Memórias do Instituto Oswaldo Cruz

Tereza C Orlando²  Mary Anne T Rubio¹  Nancy R Sturm¹  David A Campbell¹  Lucile M Floeter-winter² 

[1] ,Universidade de São Paulo Instituto de Ciências Biomédicas Departamento de ParasitologiaSão Paulo SP ,Brasil

关键词: lizard leishmania;    RNA polymerase I;    rRNA processing;    repetitive DNA;    rRNA spacer evolution;   

DOI  :  10.1590/S0074-02762002000500020

来源: SciELO

【 摘 要 】

To establish the relationships of the lizard- and mammal-infecting Leishmania, we characterized the intergenic spacer region of ribosomal RNA genes from L. tarentolae and L. hoogstraali. The organization of these regions is similar to those of other eukaryotes. The intergenic spacer region was approximately 4 kb in L. tarentolae and 5.5 kb in L. hoogstraali. The size difference was due to a greater number of 63-bp repetitive elements in the latter species. This region also contained another element, repeated twice, that had an inverted octanucleotide with the potential to form a stem-loop structure that could be involved in transcription termination or processing events. The ribosomal RNA gene localization showed a distinct pattern with one chromosomal band (2.2 Mb) for L. tarentolae and two (1.5 and 1.3 Mb) for L. hoogstraali. The study also showed sequence differences in the external transcribed region that could be used to distinguish lizard Leishmania from the mammalian Leishmania. The intergenic spacer region structure features found among Leishmania species indicated that lizard and mammalian Leishmania are closely related and support the inclusion of lizard-infecting species into the subgenus Sauroleishmania proposed by Saf'janova in 1982.

【 授权许可】

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