Leishmania (Viannia) braziliensis Transcriptome or Gene expression. Leishmania sp.

High-throughput next generation sequencing (NGS) has revealed new aspects of transcriptomes that have not been observed or were poorly described using small-scale sequencing. Using Leishmania as a model in a typical transcriptome analysis by NGS Roche 454 pyrosequencing, we found non-canonical polyadenylation of rRNA and mRNA. Leishmania RNAs are transcribed as long polycistronic pre-RNAs, and mRNAs are usually polyadenylated at the 3´-ends. The analysis of the transcriptome data revealed the presence of poly(A)-rich tails at the end of the rRNA subunits.. This phenomenon could explain the abundant amounts of rRNA observed in mRNA samples after purification by oligo (dT). Surprisingly, we found poly(A)-rich tails in the middle of predicted transcripts (rRNA and mRNA) interrupting the messages.