THE RAPESEED MITOCHONDRIAL GENE ENCODING A HOMOLOG OF THE BACTERIAL PROTEIN CCL1 IS DIVIDED INTO 2 INDEPENDENTLY TRANSCRIBED READING FRAMES

In the rapeseed mitochondrial genome we identified sequences that have a high similarity to those of a bacterial gene involved in the biogen esis of cytochromes c designated ccl1. The structure of this gene is q uite unusual, In rapeseed mitochondria, the ccl1-homologous (orf577) s equence is divided into two parts, which are al least 45 kb apart. The se two parts are transcribed separately and their transcripts are edit ed similarly to The homologous transcripts of wheat and Oenothera. How ever it was impossible to identify a mature transcript covering the wh ole coding region, a result that excludes a trans-splicing event, No o ther copy of this gene was found in either the nuclear genome or the m itochondrial genome. The protein product of orf577 is present in rapes eed mitochondria. These results raise the possibility that this divide d gene might be functional and active in rapeseed mitochondria through a novel mechanism of gene expression.