Sequence and transcriptional analysis of a chloroplast insert in the mitochondrial genome of Zea mays.

The complete sequence of a mitochondrial DNA insertional event containing the 3' portion of the chloroplast 23S-4.5S rRNA gene, the entire 5S rRNA gene and intervening sequence and all but the 3' 6 nucleotides of the arginine tRNA gene is reported. Also reported are both chloroplast/mitochondrial DNA junction sequences, 551 nucleotides of flanking mitochondrial sequences and the genomic location of this insert in Zea mays mitochondria. Utilizing the distinctive transcriptional pattern seen for mitochondrial RNA derived from root tissue relative to shoot tissue, we also reported a general experimental test for whether chloroplast sequences transposed to the mitochondrion are transcribed. Although results for the insert reported suggest it is transcriptionally inactive, the technique should be generally applicable to any transposed sequence.