The Tudor SND1 protein is an mA RNA reader essential for replication of Kaposi's sarcoma-associated herpesvirus.

-methyladenosine (mA) is the most abundant internal RNA modification of cellular mRNAs. mA is recognised by YTH domain-containing proteins, which selectively bind to mA-decorated RNAs regulating their turnover and translation. Using an mA-modified hairpin present in the Kaposi's sarcoma associated herpesvirus (KSHV) RNA, we identified seven members from the 'Royal family' as putative mA readers, including SND1. RIP-seq and eCLIP analysis characterised the SND1 binding profile transcriptome-wide, revealing SND1 as an mA reader. We further demonstrate that the mA modification of the RNA is critical for SND1 binding, which in turn stabilises the transcript. Importantly, SND1 depletion leads to inhibition of KSHV early gene expression showing that SND1 is essential for KSHV lytic replication. This work demonstrates that members of the 'Royal family' have mA-reading ability, greatly increasing their epigenetic functions beyond protein methylation.