Plant mitochondrial mat-r gene/nad1 gene complex

摘要

We have completed sequencing segments of the maize mitochondrial (mt) DNA that211u001econtains all five of the exons (A-E) of the gene (nad1) for subunit I of the 211u001erespiratory chain NADH dehydrogenase. Analysis of these sequences indicates that 211u001eexons B and C are joined by a continuous group II intron, but the remaining exons 211u001eare associated with partial group II introns and are encoded at widely separated 211u001elocations in the maize mtDNA molecule. We have shown that mature transcripts of 211u001ethe maize nad1 gene contain 23 edited nucleotides, and that transcripts of maize 211u001eand soybean mat-r genes contain 15 and 14 edits, respectively. The majority of 211u001eedits in nad1 transcripts result in amino acid replacements that increase 211u001esimilarity between the maize NAD1 protein and NAD1 proteins of other plant 211u001especies and of animal species. We found that the intron between exons b and c is 211u001enot edited. From data obtained using PCR and sequencing we have shown that 211u001etranscripts containing all possible exon combinations exist in maize 211u001emitochondria.