A novel mechanism for the initiation of Tacaribe arenavirus genome replication.
The ends of arenavirus genome and antigenome RNAs are highly conserved and where determined directly, always contain a 3' G (referred to as position +1). However, primers extended to the 5' ends of Tacaribe virus genomes and antigenomes extend to position -1. When genomes and antigenomes are annealed either inter or intramolecularly and treated with RNase A or T1, there appears to be a single unpaired G at the 5' ends of the hybrids. A single extra G is also found by cloning the 5' ends of S antigenomes, and studies with capping enzyme detect (p)ppG at the 5' ends of genome and antigenome chains. A model is proposed in which genome replication initiates with pppGpC to create the nontemplated extra G. In contrast, the nontemplated bases at the 5' ends of the N mRNAs, which extend to positions -1 to -5, were found to be capped and also heterogeneous in sequence.
Garcin
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Department of Microbiology, University of Geneva Medical School, Switzerland.
Kolakofsky
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D000818:Animals; D001116:Arenaviridae / Q000235:genetics*; D001483:Base Sequence; D002460:Cell Line; D003001:Cloning, Molecular; D005814:Genes, Viral; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D015345:Oligonucleotide Probes; D012315:RNA Caps / Q000235:genetics; D012328:RNA Viruses / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D014158:Transcription, Genetic
D015345:Oligonucleotide Probes; D012315:RNA Caps; D012333:RNA, Messenger