Variable structures of promoters regulating transcription of cp-like tRNA genes and of some native genes on the sunflower mitochondrial genome.

Promoter regions regulating the transcription of all cp-like tRNA genes encoded by the sunflower chondriome have been identified. Some of these genes are part of clusters where the first gene is a typical mitochondrial isoform. Promoters regulating the transcription of single cp-like tRNA genes have a variable structure whereas those regulating the transcription of native genes or clusters with typical mitochondrial genes in the first position conform to a similar common structure. The variability of promoter regions described in this paper could be the result of modifications of regions having, at the moment of the cpDNA insertion event, only minimal structural features as promoters.