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The polymerase subunit of a dsRNA virus plays a central role in the regulation of viral RNA metabolism
Author(s) -
Makeyev Eugeny V.,
Bamford Dennis H.
Publication year - 2000
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/19.22.6275
Subject(s) - biology , rna silencing , rna dependent rna polymerase , polymerase , rna polymerase , rna polymerase i , transcription (linguistics) , rna , microbiology and biotechnology , rna editing , rna polymerase ii , transcription factor ii d , genetics , dna , gene expression , gene , rna interference , linguistics , philosophy , promoter
Bacteriophage φ6 has a three‐segmented double‐stranded (ds) RNA genome, which resides inside a polymerase complex particle throughout the entire life cycle of the virus. The polymerase subunit P2, a minor constituent of the polymerase complex, has previously been reported to replicate both φ6‐specific and heterologous single‐stranded (ss) RNAs, giving rise to dsRNA products. In this study, we show that the enzyme is also able to use dsRNA templates to perform semi‐conservative RNA transcription in vitro without the assistance of other proteins. The polymerase synthesizes predominantly plus‐sense copies of φ6 dsRNA, medium and small segments being more efficient templates than the large one. This distribution of the test‐tube reaction products faithfully mimics viral transcription in vivo . Experiments with chimeric ssRNAs and dsRNAs show that short terminal nucleotide sequences can account for the difference in efficiency of RNA synthesis. Taken together, these results suggest a model explaining important aspects of viral RNA metabolism regulation in terms of enzymatic properties of the polymerase subunit.