Role of EhLINE1_ORF1p outside retrotransposition: Downregulation causes growth defects in <i>Entamoeba histolytica</i>.

The constitutive expression of EhLINE1_ORF1p in <i>Entamoeba histolytica</i> cells in the absence of retrotransposition suggests that this protein may serve roles beyond retrotransposition. To delve into this possibility, we generated and analyzed transcriptomic data of EhLINE1_ORF1p partial-knockdown cell lines. This analysis unveiled the significance of EhLINE1_ORF1p in the growth of <i>E. histolytica</i> cells. Our investigation of the consequences of EhLINE1_ORF1p partial-knockdown highlighted its impact on the genes involved in ribosome biogenesis, pre-rRNA processing, RNA helicase, and oxidoreductase activity, particularly those associated with amoebiasis. These affected genes are categorized as having high expression and are essential for optimal cell growth. Validation through western blotting confirmed a substantial and pronounced decline in EhLINE1_ORF1p level, and growth kinetics confirmed decline in cell growth. These findings provide compelling evidence supporting the plausible role of EhLINE1_ORF1p in regulating the growth of <i>E. histolytica</i>.