title: Homo-oligomerization of Marburgvirus VP35 is essential for its function in replication and transcription.
abstract: The nucleocapsid protein VP35 of Marburgvirus, a filovirus, acts as the cofactor of the viral polymerase and plays an essential role in transcription and replication of the viral RNA. VP35 forms complexes with the genome encapsidating protein NP and with the RNA-dependent RNA polymerase L. In addition, a trimeric complex had been detected in which VP35 bridges L and the nucleoprotein NP. It has been presumed that the trimeric complex represents the active polymerase bound to the nucleocapsid. Here we present evidence that a predicted coiled-coil domain between amino acids 70 and 120 of VP35 is essential and sufficient to mediate homo-oligomerization of the protein. Substitution of leucine residues 90 and 104 abolished (i) the probability to form coiled coils, (ii) homo-oligomerization, and (iii) the function of VP35 in viral RNA synthesis. Further, it was found that homo-oligomerization-negative mutants of VP35 could not bind to L. Thus, it is presumed that homo-oligomerization-negative mutants of VP35 are unable to recruit the polymerase to the NP/RNA template. In contrast, inability to homo-oligomerize did not abolish the recruitment of VP35 into inclusion bodies, which contain nucleocapsid-like structures formed by NP. Finally, transcriptionally inactive mutants of VP35 containing the functional homo-oligomerization domain displayed a dominant-negative phenotype. Inhibition of VP35 oligomerization might therefore represent a suitable target for antiviral intervention.
authors.affiliation: Institut für Virologie der Philipps-Universität Marburg, Robert-Koch-Str. 17, 35037 Marburg, Germany.
authors.forename: Peggy
authors.initials: P
authors.lastname: Möller
authors.forename: Nonia
authors.initials: N
authors.lastname: Pariente
authors.forename: Hans-Dieter
authors.initials: HD
authors.lastname: Klenk
authors.forename: Stephan
authors.initials: S
authors.lastname: Becker
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D001665:Binding Sites; D002460:Cell Line; D019281:Dimerization; D029024:Marburgvirus / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D014158:Transcription, Genetic; D014764:Viral Proteins / Q000502:physiology*; D054334:Viral Regulatory and Accessory Proteins; D014779:Virus Replication
chemical_list: C080980:VP35 protein, filovirus; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins