A small repeated sequence contains the transcription initiation sites for both trnfM and rrn26 in rice mitochondria.

The 76 bp sequence found in the upstream region of a gene for 26S rRNA (rrn26) is duplicated in the upstream region of a gene for initiator methionine tRNA (trnfM) in the mitochondrial genome of rice. An in vitro capping/ribonuclease protection assay and primer extension analysis demonstrated that the transcription of trnfM and of rrn26, which are at least 190 kb from one another in the rice mitochondrial genome, starts from these same sequences in the upstream regions of the respective genes. This result indicates that the short sequence that is duplicated in the upstream regions of trnfM and rrn26 in rice mtDNA is recognized as the promoter of each respective gene.