The region distal to the rRNA operon from chloroplasts of maize contains genes coding for tRNA(Arg)(ACG) and tRNA (Asn)(GUU).

The nucleotide sequence distal to the rRNA operon from maize chloroplasts has been analyzed. It contains genes coding for tRNA(Arg)(ACG) and tRNA(Asn)(GUU). The tRNA(Arg)(ACG) gene, which is separated from the last rRNA gene of the rRNA operon, the 5S rDNA, by an intergenic region of 252 bp, has the same orientation as the rRNA operon. By S1 and primer extension mapping, the existence of transcripts from the entire 5S rDNA/tDNA(Arg)(ACG) intergenic region can be demonstrated. It is, therefore, concluded that tRNA(Arg)(ACG) represents a trailer tRNA which is cotranscribed with 5S rRNA as part of the primary rRNA transcript. The tDNA(Asn)(GUU), which is separated from tDNA(Arg)(ACG) by an intergenic region of 253 bp, has the opposite orientation with respect to the rRNA operon; it, therefore, represents a separate transcriptional unit whose promoter remains to be located. It is proposed that the two tRNA genes possess a common terminator region, which functions in both directions of transcription.