Mapping of 5' and 3'-ends of sunflower mitochondrial nad6 mRNAs reveals a very complex transcription pattern which includes primary transcripts lacking 5'-UTR.

The transcription of the nad6 locus generates a highly complex pattern. Three main transcripts of 1240, 960 and 870 nt have been characterized by different approaches. The two smaller ones are apparently the most abundant of the steady-state RNA population and are generated as primary transcription products as well as by processing of the 1240 nt transcript. Their 5'-UTRs are absent or very short. Whereas the T-ends of the 960 nt transcripts contain a TGA codon the shorter one terminates at positions excluding the stop codon.