Identification of highly-disrupted tRNA genes in nuclear genome of the red alga, Cyanidioschyzon merolae 10D

• Published in: Scientific reports Vol. 3; no. 1; p. 2321
• Main Authors: Soma, Akiko, Sugahara, Junichi, Onodera, Akinori, Yachie, Nozomu, Kanai, Akio, Watanabe, Satoru, Yoshikawa, Hirofumi, Ohnuma, Mio, Kuroiwa, Haruko, Kuroiwa, Tsuneyoshi, Sekine, Yasuhiko
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 31.07.2013; Nature Publishing Group
• Subjects: 631/208/199; 631/337/1645/1792; 631/337/384/521; 631/337/574/1793; Algae; Base Sequence; Chromosome Mapping; Endonuclease; Gene Expression Regulation, Plant - genetics; Genome, Plant - genetics; Genomes; Humanities and Social Sciences; Introns; Molecular Sequence Data; multidisciplinary; Mutation - genetics; Rhodophyta - genetics; RNA, Transfer - genetics; Science; Splicing; tRNA
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep02321

The limited locations of tRNA introns are crucial for eukaryal tRNA-splicing endonuclease recognition. However, our analysis of the nuclear genome of an early-diverged red alga, Cyanidioschyzon merolae , demonstrated the first evidence of nuclear-encoded tRNA genes that contain ectopic and/or multiple introns. Some genes exhibited both intronic and permuted structures in which the 3′-half of the tRNA coding sequence lies upstream of the 5′-half and an intron is inserted into either half. These highly disrupted tRNA genes, which account for 63% of all nuclear tRNA genes, are expressed via the orderly and sequential processing of bulge-helix-bulge (BHB) motifs at intron-exon junctions and termini of permuted tRNA precursors, probably by a C. merolae tRNA-splicing endonuclease with an unidentified subunit architecture. The results revealed a considerable diversity in eukaryal tRNA intron properties and endonuclease architectures, which will help to elucidate the acquisition mechanism of the BHB-mediated disrupted tRNA genes.