An extra tRNA(Gly)(U*CU) found in ascidian mitochondria responsible for decoding non-universal codons AGA/AGG as glycine

Akiko Kondow, Tsutomu Suzuki, Shin Ichi Yokobori, Takuya Ueda, Kimitsuna Watanabe

研究成果: Article査読

27 被引用数 (Scopus)

抄録

Amino acid assignments of metazoan mitochondrial codons AGA/AGG are known to vary among animal species; arginine in Cnidaria, serine in invertebrates and stop in vertebrates. We recently found that in the mitochondria of the ascidian Halocynthia roretzi these codons are exceptionally used for glycine, and postulated that they are probably decoded by a tRNA(UCU). In order to verify this notion unambiguously, we determined the complete RNA sequence of the mitochondrial tRNA(UCU) presumed to decode codons AGA/AGG in the ascidian mitochondria, and found it to have an unidentified U derivative at the anticodon first position. We then identified the amino acids attached to the tRNA(U*CU), as well as to the conventional tRNA(Gly)(UCC) with an unmodified U34, in vivo. The results clearly demonstrated that glycine was attached to both tRNAs. Since no other tRNA capable of decoding codons AGA/AGG has been found in the mitochondrial genome, it is most probable that this tRNA(U*CU) does actually translate codons AGA/AGG as glycine in vivo. Sequencing of tRNA(Ser)(GCU), which is thought to recognize only codons AGU/AGC, revealed that it has an unmodified guanosine at position 34, as is the case with vertebrate mitochondrial tRNA(Ser)(GCU) for codons AGA/AGG. It was thus concluded that in the ascidian, codons AGU/AGC are read as serine by tRNA(Ser)(GCU), whereas AGA/AGG are read as glycine by an extra tRNA(Gly)(U*CU). The possible origin of this unorthodox genetic code is discussed.

本文言語English
ページ(範囲)2554-2559
ページ数6
ジャーナルNucleic acids research
27
12
DOI
出版ステータスPublished - 15-06-1999

All Science Journal Classification (ASJC) codes

  • 遺伝学

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