Structure and cotranscription of tobacco chloroplast genes for tRNAGlu(UUC), tRNATyr(GUA) and tRNAAsp(GUC)

Abstract
The location and nucleotide sequences of tobacco chloroplast genes for tRNA Glu (UUC), tRNA Tyr (GUA) and tRNA Asp (GUC) have been determined. These genes lie midway between the genes for α and β/ε subunits of H+-ATPase on the large single-copy region of the chloroplast DNA. The gene organization is trna Glu - 59bp spacer - tRNA Tyr - 108bp spacer - tRNA Asp on the same DNA strand. Northern blot hybridization studies revealed that these three tRNA genes are cotranscribed. The transcription initiation site was localized at 24 bp upstream from the tRNA Glu coding region and its termination site at 90 bp downstream from the tRNA Asp coding region by S1 mapping. The tricistronic tRNA precursor is thus calculated to be 512 bases long. Its processing was also studied by S1 mapping.