Genetic elements regulating packaging of the Bunyamwera orthobunyavirus genome.
The genome of Bunyamwera virus (BUN; family Bunyaviridae, genus Orthobunyavirus) comprises three segments of negative-sense, single-stranded RNA. The RNA segments are encapsidated by the viral nucleocapsid (N) protein and form panhandle-like structures through interaction of complementary sequences at their 5' and 3' termini. Transcription and replication of a BUN genome analogue (minireplicon), comprising the viral non-coding sequences flanking a reporter gene, requires just the viral RNA polymerase (L protein) and N protein. Here, sequences of Bunyamwera serogroup M segment RNAs were compared and conserved elements within nt 20-33 of the 3' and 5' non-coding regions that can affect packaging of minireplicons into virions were identified. RNA-folding models suggest that a conserved sequence within nt 20-33 of the 5' end of the genome segments maintains conserved structural features necessary for efficient transcription. Competitive packaging experiments using M, L and S segment-derived minireplicons that encode different reporter genes showed variable packaging efficiencies of the three segments. Packaging of a particular segment appeared to be independent of the presence of other segments and, for the S segment, packaging efficiency was unaffected by the inclusion of viral coding sequences in the minireplicon.
Kohl
Alain
A
Division of Virology, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G11 5JR, Scotland, UK.
Lowen
Anice C
AC
Division of Virology, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G11 5JR, Scotland, UK.
Léonard
Vincent H J
VHJ
Division of Virology, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G11 5JR, Scotland, UK.
Elliott
Richard M
RM
Division of Virology, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G11 5JR, Scotland, UK.
D020413:3' Untranslated Regions / Q000235:genetics; D020121:5' Untranslated Regions / Q000235:genetics; D002042:Bunyamwera virus / Q000235:genetics / Q000502:physiology*; D002460:Cell Line; D015967:Gene Expression Regulation, Viral; D016679:Genome, Viral; D019251:Nucleocapsid / Q000737:chemistry / Q000378:metabolism; D012367:RNA, Viral / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics; D014158:Transcription, Genetic / Q000235:genetics; D014764:Viral Proteins / Q000737:chemistry / Q000378:metabolism*; D019065:Virus Assembly / Q000235:genetics*; D014779:Virus Replication / Q000235:genetics*
D020413:3' Untranslated Regions; D020121:5' Untranslated Regions; C069882:L protein, Bunyamwera virus; D012367:RNA, Viral; D014764:Viral Proteins