Iws1, an RNA-polymerase II (RNAPII)-associated transcription elongation factor, is involved in multiple essential biological functions. It interacts with Spt6 and recruits the lysine methyltransferase Setd2 to chromatin, regulating H3K36me3, which is crucial for pre-mRNA splicing. Iws1 also interacts with REF1/Aly to mediate mRNA export. Its function is essential for mouse embryonic development, and it is expressed in most adult tissues [2,4].

In Toxoplasma gondii, Iws1-deficient parasites showed decreased ROP18 mRNA expression, increased loading of IRGs and GBPs onto the parasitophorous vacuole membrane, and decreased virulence in wild-type mice, indicating its role in regulating the parasite's fitness in IFN-γ-activated host cells [1].

In mice, knockdown of Iws1 blocked embryo development, primarily at the 8/16-cell stage, with decreased pre-mRNA splicing, mRNA export, and Nanog expression. H3K36me3 was also decreased, and concurrent knockdown of Iws1 and Supt6 blocked development at the 2-cell stage. The Pi3k/Akt pathway modulates H3K36me3 through Iws1 [2].

In liposarcoma, AKT-mediated phosphorylation of Iws1 promotes cancer stem cell maintenance, cell plasticity, and tumor metastasis, and Iws1 expression is associated with poor patient prognosis [3].

In conclusion, Iws1 is essential for multiple biological processes such as embryonic development, mRNA processing, and histone modification. Its role in diseases like liposarcoma and in the survival of Toxoplasma gondii in host cells has been revealed through loss-of-function studies. These findings highlight the importance of Iws1 in understanding disease mechanisms and potentially developing new treatment strategies.