Large-scale tRNA intron transposition in the archaeal order Thermoproteales represents a novel mechanism of intron gain

Kosuke Fujishima, Junichi Sugahara, Masaru Tomita, Akio Kanai

研究成果: Article査読

27 被引用数 (Scopus)


Recently, diverse arrangements of transfer RNA (tRNA) genes have been found in the domain Archaea, in which the tRNA is interrupted by a maximum of three introns or is even fragmented into two or three genes. Whereas most of the eukaryotic tRNA introns are inserted strictly at the canonical nucleotide position (37/38), archaeal intron-containing tRNAs have a wide diversity of small tRNA introns, which differ in their numbers and locations. This feature is especially pronounced in the archaeal order Thermoproteales. In this study, we performed a comprehensive sequence comparison of 286 tRNA introns and their genes in seven Thermoproteales species to clarify how these introns have emerged and diversified during tRNA gene evolution. We identified 46 intron groups containing sets of highly similar sequences (>70%) and showed that 16 of them contain sequences from evolutionarily distinct tRNA genes. The phylogeny of these 16 intron groups indicates that transposition events have occurred at least seven times throughout the evolution of Thermoproteales. These findings suggest that frequent intron transposition occurs among the tRNA genes of Thermoproteales. Further computational analysis revealed limited insertion positions and corresponding amino acid types of tRNA genes. This has arisen because the bulge-helix-bulge splicing motif is required at the newly transposed position if the pre-tRNA is to be correctly processed. These results clearly demonstrate a newly identified mechanism that facilitates the late gain of short introns at various noncanonical positions in archaeal tRNAs.

ジャーナルMolecular Biology and Evolution
出版ステータスPublished - 2010 10月

ASJC Scopus subject areas

  • 生態、進化、行動および分類学
  • 分子生物学
  • 遺伝学


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