Untranslated regions of mRNA and their role in regulation of gene expression in protozoan parasites

Abstract

Protozoan parasites are one of the oldest living entities in this world that throughout their existence have shown excellent resilience to the odds of survival and have adapted beautifully to ever changing rigors of the environment. In view of the dynamic environment encountered by them throughout their life cycle, and in establishing pathogenesis, it is unsurprising that modulation of gene expression plays a fundamental role in their survival. In higher eukaryotes, untranslated regions (UTRs) of transcripts are one of the crucial regulators of gene expression (influencing mRNA stability and translation efficiency). Parasitic protozoan genome studies have led to the characterization (in silico, in vitro and in vivo) of a large number of their genes. Comparison of higher eukaryotic UTRs with parasitic protozoan UTRs reveals the existence of several similar and dissimilar facets of the UTRs. This review focuses on the elements of UTRs of medically important protozoan parasites and their regulatory role in gene expression. Such information may be useful to researchers in designing gene targeting strategies linked with perturbation of host-parasite relationships leading to control of specific parasites.

Wheat glutamine synthetase TaGSr-4B is a candidate gene for a QTL of thousand grain weight on chromosome 4B

“…For the mRNA stability and translation efficiency, untranslated regions (UTRs) of genes are one of the crucial regulator (Rao et al 2017 ). In comparison with the TaGSr-4B sequences of Westonia and Kauz, no difference was found in the coding region.…”

The role of upstream open reading frames in translation regulation in the apicomplexan parasites Plasmodium falciparum and Toxoplasma gondii

“…Given the sheer number of uORFs and wide prevalence of ribosomal footprints on the 5′ leader sequences in the Apicomplexan parasites, P. falciparum and T. gondii , their role in mediating translational regulation is certainly under-recognized. Efforts to understand translational regulation in these parasites is gradually gaining momentum (reviewed in Rao et al ., 2017 ), and in this review, we highlight selected examples of genes that are regulated by uORFs giving rise to clinically relevant pathophysiology in the life cycles of these parasites. Due to the requirement of novel translation factors that promote non-canonical strategies of handling the ‘hurdles’ created by uORFs, such as reinitiation and leaky scanning, further research in this area may lead to the identification of parasite-specific, essential proteins that might serve as drug targets for therapeutics.…”

The RNA-binding protein TcUBP1 up-regulates an RNA regulon for a cell surface–associated Trypanosoma cruzi glycoprotein and promotes parasite infectivity

“…This is achieved by genetic expression programs that exhibit unique features (19,20), including the nuclear compartmentalization of stage-specific transcripts (21). It currently appears that, in the absence of precise transcriptional control, gene expression is regulated mostly by post-transcriptional mechanisms (22)(23)(24). Nearly all trypanosomal coding genes are transcribed as part of polycistronic arrays that, with a few exceptions (25), do not exhibit any association of functionally related genes.…”