title: RNA ligation via 2'-phosphomonoester, 3'5'-phosphodiester linkage: requirement of 2',3'-cyclic phosphate termini and involvement of a 5'-hydroxyl polynucleotide kinase.
abstract: Extracts of wheat germ contain a RNA ligase activity that catalyzes the conversion of linear polyribonucleotides into covalently closed circles. As reported previously, this enzyme joins two ends of a RNA substrate via a 2'-phosphomonoester, 3',5'-phosphodiester linkage. In the present work we provide evidence that a 2',3'-cyclic phosphate group at the 3' terminus is required for RNA ligation and that the 5'-hydroxyl end is phosphorylated before the two RNA ends are joined. We report on the presence of 5'-hydroxyl polynucleotide kinase and polynucleotide 2',3'-cyclic phosphate 3'-phosphodiesterase activities in wheat germ extracts. A possible involvement of these enzymes in the ligation process and a potential role of the newly described ligation pathway in RNA processing are discussed.
mesh_terms: D002474:Cell-Free System; D010770:Phosphotransferases / Q000378:metabolism*; D011116:Polynucleotide 5'-Hydroxyl-Kinase / Q000378:metabolism*; D011118:Polynucleotide Ligases / Q000378:metabolism*; D011130:RNA Ligase (ATP) / Q000378:metabolism*; D012326:RNA Splicing; D012332:RNA, Heterogeneous Nuclear / Q000378:metabolism*; D012367:RNA, Viral / Q000378:metabolism; D013379:Substrate Specificity; D014908:Triticum
chemical_list: D012332:RNA, Heterogeneous Nuclear; D012367:RNA, Viral; D010770:Phosphotransferases; D011116:Polynucleotide 5'-Hydroxyl-Kinase; D011118:Polynucleotide Ligases; D011130:RNA Ligase (ATP)