title: Small satellite of arabis mosaic virus: autolytic processing of in vitro transcripts of (+) and (-) polarity and infectivity of (+) strand transcripts.
abstract: In vitro RNA transcripts of both (+) and (-) polarities were obtained from a circularly permuted dimer clone of the small satellite of arabis mosaic virus (sArMV). The transcripts show efficient self-cleavage at the two specific sites in the sequence where the monomers were joined. Autolytic processing of the full-length transcript in both orientations releases promoter-proximate fragments (+) or (-) P, promoter-distal fragments (+) or (-) D, and the monomer fragments (+) or (-) M. The presence of an OH group at their 5' ends and a 2',3' cyclophosphate at their 3' ends suggests that (+) and (-) M originated via two self-cleavage reactions within the full-length transcript of corresponding polarity. Infectivity assays showed that the (+) M fragment but not the (-) M fragment initiates replication as efficiently as the natural linear sArMV in Chenopodium quinoa. Two (-) fragments were identified which are the result of religation activity: a P-D fragment formed by religation of P and D, and c-M, which is the result of efficient self-ligation of (-) M. In contrast, linear (+) M self-ligates in vitro to a very limited extent but could be circularized enzymically in a wheat germ extract.
authors.affiliation: Molecular Plant Pathology Laboratory, Agricultural Research Service United States, Department of Agriculture, Beltsville, MD 20705.
authors.forename: M
authors.initials: M
authors.lastname: Etscheid
authors.forename: M E
authors.initials: ME
authors.lastname: Tousignant
authors.forename: J M
authors.initials: JM
authors.lastname: Kaper
mesh_terms: D001483:Base Sequence; D003001:Cloning, Molecular; D008969:Molecular Sequence Data; D017860:Nepovirus / Q000235:genetics* / Q000472:pathogenicity; D012313:RNA / Q000737:chemistry*; D012333:RNA, Messenger / Q000737:chemistry*; D019244:RNA, Satellite; D012367:RNA, Viral / Q000737:chemistry*
chemical_list: D012333:RNA, Messenger; D019244:RNA, Satellite; D012367:RNA, Viral; D012313:RNA