Editing of cytochrome b mRNA in Physarum mitochondria

• Published in: The Journal of biological chemistry 1999-01, Vol.274 (5), p.2725-2731
• Main Authors: Wang, S.S. (University of Texas, Dallas.), Mahendran, R, Miller, D.L
• Format: Article
• Language: English
• Subjects: ADN; Amino Acid Sequence; AMINO ACID SEQUENCES; Animals; ARN; ARN MENSAJERO; ARN MESSAGER; Base Sequence; CHEMICAL COMPOSITION; CITOCROMO B; COMPLEMENTARY DNA; COMPOSICION QUIMICA; COMPOSITION CHIMIQUE; CYTB GENE; CYTOCHROME B; Cytochrome b Group - genetics; DNA; EXPRESION GENICA; EXPRESSION DES GENES; GENBANK/AF079798; GENBANK/AF079799; GENE; GENE EXPRESSION; GENES; INSERTIONS; MESSENGER RNA; MITOCHONDRIA; Mitochondria - enzymology; Mitochondria - genetics; MITOCHONDRIE; MITOCONDRIA; MOLECULAR SEQUENCE DATA; Mutagenesis, Insertional; MYXOMYCETES; NUCLEOTIDE SEQUENCE; Physarum; PHYSARUM POLYCEPHALUM; Physarum polycephalum - enzymology; Physarum polycephalum - genetics; Polymerase Chain Reaction; RNA; RNA EDITING; RNA, Messenger - metabolism; SECUENCIA NUCLEOTIDICA; Sequence Alignment; SEQUENCE NUCLEOTIDIQUE; STRUCTURAL GENES
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.274.5.2725

The reading frame in the mRNA for the cytochrome b apoprotein in mitochondria of Physarum polycephalum is created by the insertion of 43 nucleotides in the mRNA relative to the mtDNA sequence encoding it (RNA editing). Most of these insertions (31) are single cytidines; however, single uridines are inserted at six sites, and the dinucleotides, CU and GC, are inserted at two sites and one site, respectively. These insertions create a 392-codon reading frame in the mature mRNA. The amino acid sequence inferred from this reading frame has similarity to cytochrome b apoproteins encoded by other mtDNAs. The insertions are quite evenly distributed throughout the length of the reading frame with an average spacing of 27 nucleotides. This mRNA has the highest percentage (23%) of noncytidine insertions of any Physarum RNA characterized to date. cDNAs corresponding to partially edited RNAs can be enriched by selective amplification. Some cDNAs that lack the GC dinucleotide insertion are fully edited at sites flanking the GC dinucleotide insertion site. Similarly some cDNAs lack the CT dinucleotide insertion or have a CC or TT insertion flanked by a fully edited sequence. These results imply that dinucleotide editing occurs by a process separate from the global insertion of cytidines.