C19ORF66 broadly escapes viral-induced endonuclease cleavage and restricts Kaposi’s Sarcoma Associated Herpesvirus (KSHV)

William Rodriguez; Aman Srivastav; Mandy Muller

Because C19ORF66 expression was previously shown to be increased in the context of 169 various viral infections, we next sought to investigate its expression upon KSHV lytic reactivation 170 when host shutoff occurs. iSLK.219 cells were reactivated and total protein harvested at various 171 time points over the course of 96 hours. C19ORF66 expression was increased upon KSHV lytic 172 reactivation and continued to accumulate over time (Fig. 3B) . Various other proteins were also 173 previously shown to change subcellular localization in response to host shutoff (45), so we 174 proceeded to monitor C19ORF66 expression and did not find differential shuttling upon KSHV 175 lytic reactivation (Fig. 3C) . Thus, C19ORF66 escapes SOX degradation by encoding an SRE-176 like element on its 3' UTR that allows it to escape host shutoff and accumulate in lytically 177 infected cells. The copyright holder for this preprint (which was not peer-reviewed) is the author/funder. . https://doi.org/10.1101/506410 doi: bioRxiv preprint PAN promoter (Fig. 4A) . siRNA-mediated depletion of C19ORF66 in iSLK.219 cells during 187 latency and at 48h and 72h post-reactivation was efficient, reducing expression levels by 94.6%, 188 97% and 97.8%, respectively (Fig. 4B) . 72h hours post-reactivation, GFP and RFP positive cells 189