VP30

VP30 is a regulatory phosphoprotein encoded by the Ebola virus, a member of the Filoviridae family. In the viral genome, VP30 is positioned between GP and VP24, and the protein has an approximate molecular mass of 29 kDa. VP30 is expressed in the cytoplasm and is a key component of the viral transcription machinery.

Function and role in replication

VP30 functions as a transcription activator for the viral polymerase complex, which includes the L protein and VP35, in coordination with nucleoprotein-bound RNA (NP-RNA). It is required for efficient initiation of transcription of viral mRNAs from the negative-sense RNA genome. While VP30 is essential for transcription, it is not strictly required for genome replication in some experimental systems, highlighting its specific role in regulating transcription rather than genome replication. VP30 interacts with NP-RNA and with other replication complex components, helping to regulate the balance between transcription and replication.

Regulation and structure

The activity of VP30 is modulated by post-translational modifications, notably phosphorylation. Dephosphorylated VP30 is generally associated with transcriptional activity, whereas phosphorylation tends to suppress this function. Structurally, VP30 contains domains that mediate oligomerization and RNA binding, enabling it to form complexes with NP-RNA and other viral proteins. It acts as a factor that helps recruit or stabilize the transcriptional machinery at the genome template.

Clinical and research relevance

VP30 is a well-studied component in Ebola virus research and is used in reverse genetics and minigenome systems to study transcription. Because of its essential role in transcription, VP30 is a focus of antiviral research, although no specific VP30-targeted therapies are approved. Work involving VP30 requires high-containment facilities due to the pathogenic nature of Ebola virus.