Can m6A-modified RNA be used as an Anti-Viral Target?

Abstract

Kaposi’s sarcoma-associated herpesvirus (KSHV) is a DNA virus associated with several HIV-associated malignancies. Like all herpesviruses, KSHV has a biphasic life cycle encompassing a latent state and lytic replication. The KSHV replication and transcription activator viral protein, encoded from open reading frame 50 (ORF50), is the key viral protein which drives the switch between the latent and lytic phases (Guito and Lukac, 2012). We have recently demonstrated that KSHV manipulates the host cell N6-methyl adenosine (m6A) RNA modification pathway to enhance viral gene expression. Specifically, we have shown that the KSHV ORF50 transcript is m6A methylated, allowing the recruitment of the m6A reader protein, Staphylococcal nuclease domain-containing protein 1 (SND-1), resulting in the stabilisation of the ORF50 transcript and efficient KSHV lytic replication (Baquero-Perez et al. 2019). Further analysis of the m6A modified site with the ORF50 transcript has identified an RNA stem-loop, termed ORF50-1, which is a m6A-modified 43-mer, essential for SND-1 binding, thought to occur in a secondary structure/ sequence-dependent manner. Taking this into consideration, novel ligands have been assessed as effective anti-viral reagents. The importance of A versus m6A within the lytic phase of KSHV’s lifecycle will be investigated by combining in silicoscreening with biophysical techniques and cell based assays.