title: RNA editing associated with the generation of two distinct conformations of the trypanosomatid Leptomonas collosoma 7SL RNA.
abstract: Analysis of the trypanosomatid Leptomonas collosoma 7SL RNA revealed the existence of two distinct stable 7SL RNA conformers (7SL I and II). Sequence analysis of the RNAs indicated a single base difference between the conformers at position 133 (C in 7SL II and U in 7SL I) located in domain III. This change appears to be the result of a post-transcriptional editing event, since the single-copy 7SL RNA gene codes exclusively for a C at this position. The edited form (7SL I) was found preferentially in the cytoplasm, and the pre-edited form in the nucleus. 7SL I is mainly bound to ribosomes, whereas 7SL II is more abundant in ribosome-free particles. Mutations introduced in regions outside the editing site were found to occur in a single conformation, suggesting that the editing event is not the only factor that determines the conformation of the molecule. This study is the first description of an editing event on a small RNA other than tRNA and is the first report of C --> U editing in trypanosomes. We propose a novel role for RNA editing in controlling the conformation of the 7SL RNA in vivo.
authors.affiliation: Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: H
authors.initials: H
authors.lastname: Ben-Shlomo
authors.forename: A
authors.initials: A
authors.lastname: Levitan
authors.forename: N E
authors.initials: NE
authors.lastname: Shay
authors.forename: I
authors.initials: I
authors.lastname: Goncharov
authors.forename: S
authors.initials: S
authors.lastname: Michaeli
mesh_terms: D000818:Animals; D009690:Nucleic Acid Conformation; D012313:RNA / Q000737:chemistry / Q000235:genetics*; D017393:RNA Editing; D016053:RNA, Protozoan / Q000737:chemistry / Q000235:genetics*; D020733:RNA, Small Cytoplasmic; D014351:Trypanosomatina / Q000235:genetics*
chemical_list: D016053:RNA, Protozoan; D020733:RNA, Small Cytoplasmic; D012313:RNA