Disclosing 3' UTR cis-elements and putative partners involved in gene expression regulation in Leishmania spp.

To identify putative cis -elements involved in gene expression regulation in Leishmania , we previously conducted an in silico investigation to find conserved intercoding sequences (CICS) in the genomes of L . major , L . infantum , and L . braziliensis . Here, the CICS databank was explored to search for sequences that were present in the untranslated regions (UTRs) of groups of genes showing similar expression profiles during in vitro differentiation. Using a selectable marker as a reporter gene, flanked by either an intact 3' UTR or a UTR lacking the conserved element, the regulatory role of a CICS was confirmed. We observed that the pattern of modulation of the mRNA levels was altered in the absence of the CICS. We also identified putative CICS RNA-binding proteins. This study suggests that the publicly available CICS database is a useful tool for identifying regulatory cis -elements for Leishmania genes and suggests the existence of post-transcriptional regulons in Leishmania .