The effect of ORF57 knockout (KO) on host expression in iSLK/Bac16 cells.

Kaposi’s sarcoma-associated herpesvirus (KSHV) is a human oncogenic virus associated with various malignancies, including Kaposi’s sarcoma, primary effusion lymphoma, and multicentric Castleman’s disease. The expression of viral products is essential for initiating and sustaining KSHV-induced tumors. KSHV ORF57, a viral RNA-binding protein, plays a crucial role in regulating viral gene expression at the posttranscriptional level by promoting viral RNA stability, splicing, and translation. In addition, ORF57 dysregulates host gene expression to promote viral replications. The iSLK/Bac16 cells were generated by stable transfection of the KSHV genome cloned into bacterial artificial chromosome (Brulois et al. 2012; PMID: 22740391). The ORF57 knockout (57KO) was generated using Cas9/CRISPR by expressing two gRNA flanking ORF57 locus in the KSHV genome (BeltCappellino et al., 2019; PMID: 31413125). The cells expressing Cas9 but no gRNA were used as control wild-type samples.