title: RNA binding properties of bunyamwera virus nucleocapsid protein and selective binding to an element in the 5' terminus of the negative-sense S segment.
abstract: The genome of Bunyamwera virus (BUN) (family Bunyaviridae, genus Bunyavirus) comprises three negative-sense RNA segments which act as transcriptional templates for the viral polymerase only when encapsidated by the nucleocapsid protein (N). Previous studies have suggested that the encapsidation signal may reside within the 5' terminus of each segment. The BUN N protein was expressed as a 6-histidine-tagged fusion protein in Escherichia coli and purified by metal chelate chromatography. An RNA probe containing the 5'-terminal 32 and 3'-terminal 33 bases of the BUN S (small) genome segment was used to investigate binding by the N protein in vitro using gel mobility shift and filter binding assays. On acrylamide gels a number of discrete RNA-N complexes were resolved, and analysis of filter binding data indicated a degree of cooperativity in N protein binding. RNA-N complexes were resistant to digestion with up to 1 microg of RNase A per ml. Competition assays with a variety of viral and nonviral RNAs identified a region within the 5' terminus of the BUN S segment for which N had a high preference for binding. This site may constitute the signal for initiation of encapsidation by N.
authors.affiliation: Division of Virology, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G11 5JR, Scotland.
authors.forename: J C
authors.initials: JC
authors.lastname: Osborne
authors.forename: R M
authors.initials: RM
authors.lastname: Elliott
mesh_terms: D001667:Binding, Competitive; D002042:Bunyamwera virus / Q000235:genetics* / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D016679:Genome, Viral; D006639:Histidine / Q000378:metabolism; D007700:Kinetics; D015636:Magnesium Chloride / Q000494:pharmacology; D019590:Nucleocapsid Proteins / Q000235:genetics / Q000378:metabolism*; D016372:RNA, Antisense / Q000235:genetics / Q000378:metabolism; D012367:RNA, Viral / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012260:Ribonucleases / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology
chemical_list: D019590:Nucleocapsid Proteins; D016372:RNA, Antisense; D012367:RNA, Viral; D011993:Recombinant Fusion Proteins; D015636:Magnesium Chloride; D012965:Sodium Chloride; D006639:Histidine; D012260:Ribonucleases