title: Bunyamwera bunyavirus RNA synthesis requires cooperation of 3'- and 5'-terminal sequences.
abstract: Bunyamwera virus (BUNV) is the prototype of both the Orthobunyavirus genus and the Bunyaviridae family of segmented negative-sense RNA viruses. The tripartite BUNV genome consists of small (S), medium (M), and large (L) segments that are each transcribed to yield a single mRNA and are replicated to generate an antigenome that acts as a template for synthesis of further genomic strands. As for all negative-sense RNA viruses, the 3'- and 5'-terminal nontranslated regions (NTRs) of the BUNV S, M, and L segments exhibit nucleotide complementarity and, except for one conserved U-G pairing, this complementarity extends for 15, 18, and 19 nucleotides, respectively. We investigated whether the complementarity of 3' and 5' NTRs reflected a functional requirement for terminal cooperation to promote BUNV RNA synthesis or, alternatively, was a consequence of genomic and antigenomic NTRs having similar functions requiring sequence conservation. We show that cooperation between 3'- and 5'-NTR sequences is required for BUNV RNA synthesis, and our results suggest that this cooperation is due to nucleotide complementarity allowing 3' and 5' NTRs to associate through base-pairing interactions. To examine the importance of complementarity in promoting BUNV RNA synthesis, we utilized a competitive replication assay able to examine the replication ability of all possible combinations of interacting nucleotides within a defined region of BUNV 3' and 5' NTRs. We show here that maximal RNA replication was signaled when sequences exhibiting perfect complementarity within 3' and 5' NTRs were selected.
authors.affiliation: Department of Microbiology, University of Alabama School of Medicine, Birmingham, Alabama 35294, USA. jbarr@uab.edu
authors.forename: John N
authors.initials: JN
authors.lastname: Barr
authors.forename: Gail W
authors.initials: GW
authors.lastname: Wertz
mesh_terms: D020413:3' Untranslated Regions / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020121:5' Untranslated Regions / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D020029:Base Pairing; D001483:Base Sequence; D002042:Bunyamwera virus / Q000235:genetics*; D002460:Cell Line; D006224:Cricetinae; D016679:Genome, Viral; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009690:Nucleic Acid Conformation; D012367:RNA, Viral / Q000096:biosynthesis*; D013698:Templates, Genetic; D014779:Virus Replication
chemical_list: D020413:3' Untranslated Regions; D020121:5' Untranslated Regions; D012367:RNA, Viral