title: C to U editing at position 32 of the anticodon loop precedes tRNA 5' leader removal in trypanosomatids.
abstract: In all organisms, precursor tRNAs are processed into mature functional units by post-transcriptional changes. These involve 5' and 3' end trimming as well as the addition of a significant number of chemical modifications, including RNA editing. The only known example of non-organellar C to U editing of tRNAs occurs in trypanosomatids. In this system, editing at position 32 of the anticodon loop of tRNA(Thr)(AGU) stimulates, but is not required for, the subsequent formation of inosine at position 34. In the present work, we expand the number of C to U edited tRNAs to include all the threonyl tRNA isoacceptors. Notably, the absence of a naturally encoded adenosine, at position 34, in two of these isoacceptors demonstrates that A to I is not required for C to U editing. We also show that C to U editing is a nuclear event while A to I is cytoplasmic, where C to U editing at position 32 occurs in the precursor tRNA prior to 5' leader removal. Our data supports the view that C to U editing is more widespread than previously thought and is part of a stepwise process in the maturation of tRNAs in these organisms.
authors.affiliation: Department of Microbiology, The Ohio State RNA Group, The Ohio State University, Columbus, Ohio 43210, USA.
authors.forename: Kirk W
authors.initials: KW
authors.lastname: Gaston
authors.forename: Mary Anne T
authors.initials: MA
authors.lastname: Rubio
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Spears
authors.forename: Irena
authors.initials: I
authors.lastname: Pastar
authors.forename: F Nina
authors.initials: FN
authors.lastname: Papavasiliou
authors.forename: Juan D
authors.initials: JD
authors.lastname: Alfonzo
mesh_terms: D000818:Animals; D001483:Base Sequence; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D017393:RNA Editing; D012323:RNA Processing, Post-Transcriptional; D012346:RNA, Transfer, Amino Acyl / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014346:Trypanosoma brucei brucei / Q000235:genetics* / Q000378:metabolism*
chemical_list: D012346:RNA, Transfer, Amino Acyl