Unexplored Molecular Features of the Entamoeba histolytica RNA Lariat Debranching Enzyme Dbr1 Expression Profile
Background:
The RNA lariat debranching enzyme (Dbr1) plays multiple roles in RNA metabolism, including hydrolysis of the 2′-5′ phosphodiester bond in intron lariats, facilitation of Ty1 and HIV-1 retrotransposition, and involvement in small nuclear ribonucleoprotein (snRNP) recycling during splicing. These functions position Dbr1 as a key regulator of RNA turnover. Despite extensive functional studies on Dbr1, the expression profile of the endogenous Dbr1 gene has not, to our knowledge, been previously characterized.
Findings:
In this study, we report for the first time that EhDbr1 mRNA in Entamoeba histolytica exhibits a very short half-life (less than 30 minutes), while its encoded protein is highly stable and persists until the death of the trophozoite culture. Intriguingly, we also observed that the EhDbr1 protein is localized at the cytoplasmic face of the nuclear periphery, a distribution distinct from that of its human counterpart.
Comparison of these findings with data from other organisms supports the hypothesis that Dbr1 gene expression is finely regulated and evolutionarily conserved across eukaryotes. This is especially notable in E. histolytica, a unicellular but intron-rich protozoan parasite and the causative agent of amoebiasis. In this organism, the efficient removal and processing of intron lariats may prevent their accumulation and potentially repurpose them into non-coding RNAs involved in virulence.
Conclusion:
Our results underscore the importance of studying Dbr1 mRNA turnover and gene expression, particularly in E. histolytica, where its regulatory role may extend beyond RNA degradation to influence pathogenicity. Further investigation is warranted to explore the broader functional landscape of Dbr-1, including its potential contributions to RNA-based regulatory mechanisms in protozoan parasites.