Trichomonas vaginalis ribosomal RNA: identification and characterisation of the transcription promoter and terminator sequences.

Bernardo Franco, Roberto Hernández, Imelda López-Villaseñor

Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, México, DF, Mexico.

Molecular and biochemical parasitology 2012 Sep

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Trichomonas vaginalis is a parasitic protozoan of both medical and biological relevance. Transcriptional studies in this organism have focused mainly on type II pol promoters, whereas the elements necessary for transcription by polI or polIII have not been investigated. Here, with the aid of a transient transcription system, we characterised the rDNA intergenic region, defining both the promoter and the terminator sequences required for transcription. We defined the promoter as a compact region of approximately 180 bp. We also identified a potential upstream control element (UCE) that was located 80 bp upstream of the transcription start point (TSP). A transcription termination element was identified within a 34 bp region that was located immediately downstream of the 28S coding sequence. The function of this element depends upon polarity and the presence of both a stretch of uridine residues (U's) and a hairpin structure in the transcript. Our observations provide a strong basis for the study of DNA recognition by the polI transcriptional machinery in this early divergent organism. Copyright © 2012 Elsevier B.V. All rights reserved.

Citation

Bernardo Franco, Roberto Hernández, Imelda López-Villaseñor. Trichomonas vaginalis ribosomal RNA: identification and characterisation of the transcription promoter and terminator sequences. Molecular and biochemical parasitology. 2012 Sep;185(1):1-9