Dyskinetoplastic Trypanosoma brucei contains functional editing complexes.
Mitochondrial pre-mRNAs undergo posttranscriptional RNA editing as directed by small guide RNAs (gRNAs) to produce functional mRNAs in kinetoplastid protozoa. The pre-mRNAs and gRNAs are encoded in the maxicircle and minicircle components, respectively, of the kinetoplastid mitochondrial DNA (kDNA), and editing is catalyzed by a multienzyme protein complex. Trypanosoma evansi AnTat3/3, which lacks maxicircles but retains a single class of minicircles, and a dyskinetoplastic mutant of Trypanosoma brucei EATRO164, which is devoid of kDNA, were both shown to retain genes and proteins for the editing complex. The proteins are present in complexes that immunoprecipitate and sediment indistinguishably from wild-type complexes. The complexes catalyze precleaved insertion and deletion editing as well as full-round deletion editing in vitro. Thus, mutants which lack the natural substrates for RNA editing and all or most gRNAs retain editing complexes that contain the four primary catalytic activities of editing and function in editing, at least in vitro. Therefore neither pre-mRNA nor gRNA is required to form functional RNA-editing complexes.
Domingo
Gonzalo J
GJ
Seattle Biomedical Research Institute, Seattle, Washington 98109, USA.
Palazzo
Setareh S
SS
Wang
Bingbing
B
Pannicucci
Brian
B
Salavati
Reza
R
Stuart
Kenneth D
KD
D000818:Animals; D018105:DNA, Kinetoplast / Q000235:genetics / Q000378:metabolism; D004720:Endonucleases / Q000378:metabolism; D005092:Exonucleases / Q000378:metabolism; D015870:Gene Expression; D005796:Genes; D017125:Genes, Protozoan; D009154:Mutation; D015800:Protozoan Proteins / Q000378:metabolism; D017393:RNA Editing; D011130:RNA Ligase (ATP) / Q000378:metabolism; D017394:RNA, Guide, Kinetoplastida / Q000235:genetics / Q000378:metabolism; D016053:RNA, Protozoan; D014346:Trypanosoma brucei brucei / Q000235:genetics* / Q000378:metabolism
D018105:DNA, Kinetoplast; D015800:Protozoan Proteins; D016053:RNA, Protozoan; D004720:Endonucleases; D005092:Exonucleases; D011130:RNA Ligase (ATP); D017394:RNA, Guide, Kinetoplastida