Viral hijacking of the TENT4-ZCCHC14 complex protects viral RNAs via mixed tailing

ABSTRACT: TENT4 enzymes generate “mixed tails” on mRNAs by adding adenosines with intermittent non-adenosine residues, which protect mRNAs from deadenylation. Here we discover the extensive mixed tailing in the transcripts of two distinct DNA viruses, hepatitis B virus (HBV) and human cytomegalovirus (HCMV), and their striking similarity in the mechanism to exploit the TENT4-ZCCHC14 complex. TAIL-seq analyses of HBV and HCMV RNAs revealed that TENT4A and TENT4B are responsible for the mixed tailing and protection of viral poly(A) tails. By fCLIP-seq on HBV-producing cells, we found that the HBV posttranscriptional regulatory element (PRE) is the primary site of the TENT4 interactome. A hairpin with a CNGGN-type pentaloop in the PRE is critical for TENT4-dependent regulation. Unexpectedly, HCMV also utilizes a similar pentaloop hairpin, an interesting example of convergent evolution. We further found that the CNGGN pentaloop is recognized by the SAM domain-containing ZCCHC14 protein which in turn recruits TENT4 to stabilize viral transcripts. Altogether, our study reveals the action mechanism of PRE that has been widely used to enhance gene expression, and introduces the TENT4-ZCCHC14 complex as the key host factor and a potential target for antiviral therapeutics.

INSTRUMENT(S): Orbitrap Fusion Lumos

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Epithelial Cell, Cell Culture

SUBMITTER: Young-suk Lee  

LAB HEAD: V. Narry Kim

PROVIDER: PXD018061 | Pride | 2020-04-27

REPOSITORIES: Pride