A herpesvirus protein selectively inhibits cellular mRNA nuclear export

Nuclear export of mRNA is essential for eukaryotic cells to establish the flow of genetic information in the nucleus to protein synthesis in the cytoplasm. This transport process is highly regulated to ensure efficient and accurate gene expression. Viruses are well known for their ability to manipulate host gene expression. Here, we report that ORF10 of Kaposi’s sarcoma associated herpesvirus (KSHV), a nuclear DNA virus, inhibits mRNA export in a transcript-selective manner to control cellular gene expression. This export inhibitory effect of ORF10 requires the interaction with an RNA export factor, Rae1. Genome-wide analysis by RNA sequencing revealed the subset of cellular mRNAs whose nuclear export is blocked by ORF10. The 3’ untranslated regions (3’ UTRs) of ORF10-targeted transcripts confer their sensitivity to nuclear export inhibition by ORF10. In the context of KSHV replication, the interaction of ORF10 with Rae1 is important for the virus to express viral genes and produce infectious virions. Our results suggest that a nuclear replicating DNA virus can selectively interfere with RNA export through Rae1 to restrict host gene expression for optimal viral replication. Overall design: 1. Study lytic replication profile of KSHV WT and KSHV ORF10 mutant. 2. Study role of ORF10 on host mRNA nuclear export