Transcripts encoding the nanovirus master replication initiator proteins are terminally redundant.
The multicomponent single-stranded DNA plant nanoviruses encode unique master replication initiator (Rep) proteins. We have mapped the 5' and 3' termini of the corresponding polyadenylated mRNAs from faba bean necrotic yellows virus (FBNYV) and subterranean clover stunt virus and found that these are terminally redundant by up to about 160 nt. Moreover, the origin of viral DNA replication is transcribed into RNA that is capable of folding into extended secondary structures. Other nanovirus genome components, such as the FBNYV DNA encoding the protein Clink or an FBNYV DNA encoding a non-essential para-Rep protein, are not transcribed in such a unique fashion. Thus, terminally redundant mRNAs and the resulting transcription of the replication origin appear to be restricted to nanovirus master Rep DNAs. We speculate that this may be a way to regulate the expression of the essential master Rep protein.
Grigoras
Ioana
I
Institut des Sciences du Végétal, CNRS, 91198 Gif sur Yvette, France.
Timchenko
Tatiana
T
Institut des Sciences du Végétal, CNRS, 91198 Gif sur Yvette, France.
Gronenborn
Bruno
B
Institut des Sciences du Végétal, CNRS, 91198 Gif sur Yvette, France.
D004265:DNA Helicases / Q000378:metabolism*; D004277:DNA, Single-Stranded / Q000378:metabolism; D004279:DNA, Viral / Q000096:biosynthesis; D004268:DNA-Binding Proteins / Q000378:metabolism*; D007887:Fabaceae / Q000821:virology; D015967:Gene Expression Regulation, Viral; D016679:Genome, Viral; D008969:Molecular Sequence Data; D025682:Nanovirus / Q000235:genetics* / Q000502:physiology*; D010942:Plant Viruses / Q000235:genetics* / Q000502:physiology; D015534:Trans-Activators / Q000378:metabolism*
D004277:DNA, Single-Stranded; D004279:DNA, Viral; D004268:DNA-Binding Proteins; D015534:Trans-Activators; C045264:replication initiator protein; D004265:DNA Helicases