Direct visualization of uridylate deletion in vitro suggests a mechanism for kinetoplastid RNA editing.
Deletion of uridylates from the 3'-most editing site of synthetic ATPase 6 pre-mRNA can be visualized directly by coincubation of a radiolabeled substrate RNA and a synthetic gRNA in 20S fractions of T.brucie mitochondrial lysates. Substrate RNA cleavage is gRNA directed and occurs 3' to the uridylates to be deleted. U residues appear to be sequentially removed from the 3' end of the 5' cleavage product prior to religation of the two pre-mRNA halves. gRNA/mRNA chimeric molecules are also produced. Time course experiments indicate that chimeras appear after cleavage intermediates and edited product. Furthermore, a mutant gRNA promotes formation of edited product but not detectable chimeras. Our results suggest a model for kinetoplastid RNA editing in which chimeric molecules are nonproductive end products of editing and not intermediates that serve as a repository for deleted U's.
Seiwert
S D
SD
Seattle Biomedical Research Institute, Washington, 98109, USA.
Heidmann
S
S
Stuart
K
K
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D001483:Base Sequence; D018105:DNA, Kinetoplast / Q000235:genetics*; D056890:Eukaryota / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009690:Nucleic Acid Conformation; D017393:RNA Editing; D012322:RNA Precursors / Q000235:genetics; D016053:RNA, Protozoan / Q000235:genetics; D013379:Substrate Specificity; D013997:Time Factors; D014529:Uridine / Q000378:metabolism*
D018105:DNA, Kinetoplast; D012322:RNA Precursors; D016053:RNA, Protozoan; D000251:Adenosine Triphosphatases; D014529:Uridine