title: Alternative splicing by participation of the group II intron ORF in extremely halotolerant and alkaliphilic Oceanobacillus iheyensis.
abstract: Group II introns inserted into genes often undergo splicing at unexpected sites, and participate in the transcription of host genes. We identified five copies of a group II intron, designated Oi.Int, in the genome of an extremely halotolerant and alkaliphilic bacillus, Oceanobacillus iheyensis. The Oi.Int4 differs from the Oi.Int3 at four bases. The ligated exons of the Oi.Int4 could not be detected by RT-PCR assays in vivo or in vitro although group II introns can generally self-splice in vitro without the involvement of an intron-encoded open reading frame (ORF). In the Oi.Int4 mutants with base substitutions within the ORF, ligated exons were detected by in vitro self-splicing. It was clear that the ligation of exons during splicing is affected by the sequence of the intron-encoded ORF since the splice sites corresponded to the joining sites of the intron. In addition, the mutant introns showed unexpected multiple products with alternative 5' splice sites. These findings imply that alternative 5' splicing which causes a functional change of ligated exons presumably has influenced past adaptations of O. iheyensis to various environmental changes.
authors.affiliation: Microbial Genome Research Group, Japan Agency for Marine-Earth Science and Technology, 2–15 Natsushima, Yokosuka 237–0061, Japan. cheegj08@dongyang.ac.kr
authors.forename: Gab-Joo
authors.initials: GJ
authors.lastname: Chee
authors.forename: Hideto
authors.initials: H
authors.lastname: Takami
mesh_terms: D000468:Alkalies / Q000378:metabolism*; D017398:Alternative Splicing; D056449:Bacillales / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D001483:Base Sequence; D007438:Introns; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D016366:Open Reading Frames; D022821:RNA Splice Sites; D012329:RNA, Bacterial / Q000737:chemistry / Q000235:genetics; D012965:Sodium Chloride / Q000378:metabolism*
chemical_list: D000468:Alkalies; D022821:RNA Splice Sites; D012329:RNA, Bacterial; D012965:Sodium Chloride