New Study Reveals Mechanism for HBV PRE-mediated Nuclear Export of Intronless mRNA

To maximize the production of viral proteins, several viruses have evolved proteins and/or cis-acting RNA elements that specifically recruit cellular mRNA export factors for exporting viral mRNAs. Hepatitis B virus (HBV) encodes several intronless viral mRNAs. Expression of HBV viral intronless mRNAs that encode surface proteins is dependent upon a cis-element named post-transcriptional regulatory element (PRE). However, the nuclear export pathway that is used by PRE remains unclear.

A research team led by Prof. CHENG Hong, at the Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, in collaboration with Prof. LI Guohui, at the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, revealed the mechanism for PRE-mediated nuclear export of intronless mRNAs. They demonstrated that a sub-element of PRE, named SEP1, directly binds the cellular zinc finger protein ZC3H18 that recruits the mRNA export machinery TREX to promote nuclear export of intronless mRNAs. This work also identified several novel cellular mRNA export factors.

This study entitled “A Sub-Element in PRE enhances nuclear export of intronless mRNAs by recruiting the TREX complex via ZC3H18” was published online in Nucleic Acids Research on Apr 29, 2014. This work was supported by grants from the Ministry of Science and Technology of China and the National Natural Science Foundation of China.

Models for the roles of SEP1-associating proteins in the nuclear export of PRE-containing mRNAs and spliced cellular mRNAs. (Image provided by Prof. CHENG Hong’s group)