Structure and Functional Analysis of the RNA- and Viral Phosphoprotein-Binding Domain of Respiratory Syncytial Virus M2-1 Protein

PLoS Pathogens

Magali Aumont-Nicaise¹  Christina Sizun²  François Bontems²  Safa Lassoued²  Virginie Dubosclard³  Jean-François Eléouët³  Marie-Lise Blondot³  Jenna Fix³ 

[1] IBBMC, Université Paris-XI, Orsay, France;Institut de Chimie des Substances Naturelles, CNRS UPR 2301, Gif-sur-Yvette, France;Unité de Virologie et Immunologie Moléculaires (UR892), INRA, Jouy-en-Josas, France

关键词: RNA synthesis;    Sequence alignment;    RNA-binding proteins;    Positive-sense RNA viruses;    Messenger RNA;    Sequence motif analysis;    Polymerases;    RNA sequences;   

DOI  :  10.1371/journal.ppat.1002734

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Respiratory syncytial virus (RSV) protein M2-1 functions as an essential transcriptional cofactor of the viral RNA-dependent RNA polymerase (RdRp) complex by increasing polymerase processivity. M2-1 is a modular RNA binding protein that also interacts with the viral phosphoprotein P, another component of the RdRp complex. These binding properties are related to the core region of M2-1 encompassing residues S58 to K177. Here we report the NMR structure of the RSV M2-158–177 core domain, which is structurally homologous to the C-terminal domain of Ebola virus VP30, a transcription co-factor sharing functional similarity with M2-1. The partial overlap of RNA and P interaction surfaces on M2-158–177, as determined by NMR, rationalizes the previously observed competitive behavior of RNA versus P. Using site-directed mutagenesis, we identified eight residues located on these surfaces that are critical for an efficient transcription activity of the RdRp complex. Single mutations of these residues disrupted specifically either P or RNA binding to M2-1 in vitro. M2-1 recruitment to cytoplasmic inclusion bodies, which are regarded as sites of viral RNA synthesis, was impaired by mutations affecting only binding to P, but not to RNA, suggesting that M2-1 is associated to the holonucleocapsid by interacting with P. These results reveal that RNA and P binding to M2-1 can be uncoupled and that both are critical for the transcriptional antitermination function of M2-1.

【 授权许可】

CC BY