title: Monomeric linear RNA of citrus exocortis viroid resulting from processing in vivo has 5'-phosphomonoester and 3'-hydroxyl termini: implications for the RNase and RNA ligase involved in replication.
abstract: Members of the family Pospiviroidae, like Citrus exocortis viroid (CEVd), replicate through an RNA-based asymmetric rolling-circle mechanism in which oligomeric plus-strand [(+)] RNA intermediates are cleaved to monomeric linear (ml) RNA and then circularized. Here we show, by rapid amplification of 5' and 3' cDNA ends and in vitro ligation assays, that ml CEVd (+) RNA resulting from cleavage of a dimeric transcript transgenically expressed in Arabidopsis thaliana contains 5'-phosphomonoester and 3'-hydroxyl termini. The nature of these termini and the double-stranded structure previously proposed as the substrate for cleavage in vivo suggest that a type III RNase catalyzes cleavage and an RNA ligase distinct from tRNA ligase promotes circularization.
authors.affiliation: Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV), Avenida de los Naranjos, 46022 Valencia, Spain. jadaros@ibmcp.upv.es
authors.forename: María-Eugenia
authors.initials: ME
authors.lastname: Gas
authors.forename: Diego
authors.initials: D
authors.lastname: Molina-Serrano
authors.forename: Carmen
authors.initials: C
authors.lastname: Hernández
authors.forename: Ricardo
authors.initials: R
authors.lastname: Flores
authors.forename: José-Antonio
authors.initials: JA
authors.lastname: Daròs
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000821:virology; D001483:Base Sequence; D004261:DNA Replication / Q000235:genetics*; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D030821:Plants, Genetically Modified / Q000235:genetics / Q000821:virology; D011130:RNA Ligase (ATP) / Q000235:genetics / Q000378:metabolism*; D012367:RNA, Viral / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D012260:Ribonucleases / Q000235:genetics / Q000378:metabolism*; D014772:Viroids / Q000235:genetics*; D014779:Virus Replication / Q000235:genetics*
chemical_list: D012367:RNA, Viral; D012260:Ribonucleases; D011130:RNA Ligase (ATP)