Insertional editing of mitochondrial tRNAs of Physarum polycephalum and Didymium nigripes.
Mol Cell Biol
; 18(12): 7521-7, 1998 Dec.
Article
em En
| MEDLINE
| ID: mdl-9819437
ABSTRACT
tRNAs encoded on the mitochondrial DNA of Physarum polycephalum and Didymium nigripes require insertional editing for their maturation. Editing consists of the specific insertion of a single cytidine or uridine relative to the mitochondrial DNA sequence encoding the tRNA. Editing sites are at 14 different locations in nine tRNAs. Cytidine insertion sites can be located in any of the four stems of the tRNA cloverleaf and usually create a G. C base pair. Uridine insertions have been identified in the T loop of tRNALys from Didymium and tRNAGlu from Physarum. In both tRNAs, the insertion creates the GUUC sequence, which is converted to GTPsiC (Psi = pseudouridine) in most tRNAs. This type of tRNA editing is different from other, previously described types of tRNA editing and resembles the mRNA and rRNA editing in Physarum and Didymium. Analogous tRNAs in Physarum and Didymium have editing sites at different locations, indicating that editing sites have been lost, gained, or both since the divergence of Physarum and Didymium. Although cDNAs derived from single tRNAs are generally fully edited, cDNAs derived from unprocessed polycistronic tRNA precursors often lack some of the editing site insertions. This enrichment of partially edited sequences in unprocessed tRNAs may indicate that editing is required for tRNA processing or at least that RNA editing occurs as an early event in tRNA synthesis.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Physarum
/
Mixomicetos
/
RNA
/
RNA de Transferência
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RNA de Protozoário
/
Edição de RNA
Limite:
Animals
Idioma:
En
Revista:
Mol Cell Biol
Ano de publicação:
1998
Tipo de documento:
Article