Assembly of a functional Machupo virus polymerase complex

作者：Kranzusch Philip J; Schenk Andreas D; Rahmeh Amal A; Radoshitzky Sheli R; Bavari Sina; Walz Thomas; Whelan Sean P J^*

来源：Proceedings of the National Academy of Sciences of the United States of America, 2010, 107(46): 20069-20074.

DOI：10.1073/pnas.1007152107

• segmented negative-strand RNA virus
• L protein structure
• RNA binding
• electron microscopy

Segmented negative-sense viruses of the family Arenaviridae encode a large polymerase (L) protein that contains all of the enzymatic activities required for RNA synthesis. These activities include an RNA-dependent RNA polymerase (RdRP) and an RNA endonuclease that cleaves capped primers from cellular mRNAs to prime transcription. Using purified catalytically active Machupo virus L, we provide a view of the overall architecture of this multifunctional polymerase and reconstitute complex formation with an RNA template in vitro. The L protein contains a central ring domain that is similar in appearance to the RdRP of dsRNA viruses and multiple accessory appendages that may be responsible for 5' cap formation. RNA template recognition by L requires a sequence-specific motif located at positions 2-5 in the 3' terminus of the viral genome. Moreover, L-RNA complex formation depends on single-stranded RNA, indicating that inter-termini dsRNA interactions must be partially broken for complex assembly to occur. Our results provide a model for arenavirus polymerase-template interactions and reveal the structural organization of a negative-strand RNA virus L protein.

• 出版日期2010-11-16