The nucleotide sequence of the maize and spinach chloroplast isoleucine transfer RNA encoded in the 16S to 23S rDNA spacer.

The sequence of maize chloroplast tRNAIle2, encoded in the 16S to 23S rDNA spacer, was determined using in vitro labeling techniques. The sequence is: pG-G-G-C-U-A-U-U-A-G-C-U-C-A-G-U-Gm-G-D-A-G-A-G-C-m22G-C-G-C-C-C-C-U-G-A-U-t6A- A-G-G-G-C-G-A-G-m7G-acp3U-C-U-C-U-G-G-T-psi-C-A-A-G-U-C-C-A-G-G-A-U-G-G-C-C-C-A -C-C-AOH. This sequence is identical to that predicted from the corresponding gene sequence, after excision of a long intervening sequence (1), but shows the post-transcriptional modifications of this tRNA. Furthermore it demonstrates that the excision of the intron occurs after the second base following the anticodon and that this gene, which is over 1000 base-pair long, is transcribed and processed into a mature functional chloroplast-tRNA. The sequence of maize (a monocot) and spinach (a dicot) tRNAIle2 are shown to be identical.