Results indicated that more than one region was responsible for changing GFP mRNA inhibitor Bortezomib and protein levels in epimastigotes and metacyclic forms [65], suggesting that multiple cis-acting elements are present in GP82 3��UTR and might bind to distinct RNA-binding proteins (RBP). The first trans-acting factor identified in T. cruzi was TcUBP1 (T. cruzi uridine binding protein 1), which binds to AU-rich elements of the TcSMUG mRNA leading to its destabilization [71]. In addition to TcSMUG, other 39 transcripts were found bound to TcUBP1 by co-immunoprecipitation assays [68]. One common cis-acting element was identified in the 3��UTRs of the majority of these TcUBP1 target mRNAs. This cis-element was used to predict novel UBP1 target mRNAs and GP82 was one of them [68].

Therefore, TcUBP1 could be one of the trans-acting factors involved in GP82 mRNA stability. A schematic representation of the mechanism controlling GP82 gene expression is shown in Figure 3.Figure 3Comparison of GP82 mRNA post-transcriptional control mechanisms in (a) epimastigotes and (b) metacyclic trypomastigotes. In epimastigotes, GP82 mRNA interacts with possibly more than one RNA-binding protein (RBP), which binds to different cis-elements …There are growing pieces of evidence suggesting the presence of post-transcriptional operons in trypanosomes, mediated by the coordinated interaction between cis-elements and trans-acting factors [68, 72]. It was demonstrated that a group of T. brucei stage-regulated proteins share a specific sequence motif in the 3��UTR (reviewed in [72]). Also, two RBPs from T.

cruzi, TcUBP1, and TcUBP3, preferentially associate with a set of functionally related transcripts bearing the same RNA motif that is recognized by each protein [68]. These post-transcriptional operons could explain how coordinately expression regulation is achieved in organisms where gene-specific transcriptional control is absent.6. Concluding Remarks and PerspectivesGP82 shows a modular organization, with some variation of N-terminal region flanking a conserved central core where the binding sites to mammalian cell and gastric mucin are located. The function of GP82 as adhesin in host cell invasion process could expose the protein to an intense conservative and selective pressure. The potential variability of GP82 genes suggests that they are not susceptible to mutation.

The many isoforms of GP82 and its multiple N-terminal variants suggest that some GP82 family members might display different cellular localizations and functions. The challenge is to ascertain the relationships between GP82 gene sequences, Drug_discovery protein isoforms, and its distinct or overlapping functions.GP82 is a GPI-anchored surface protein, synthesized as a 70kDa precursor devoid of N-linked sugars and when mature has an apparent molecular weight of 82kDa.