Reverse splicing of a mobile twin-ribozyme group I intron into the natural small subunit rRNA insertion site.
A mobile group I intron containing two ribozyme domains and a homing endonuclease gene (twin-ribozyme intron organization) can integrate by reverse splicing into the small subunit rRNA of bacteria and yeast. The integration is sequence-specific and corresponds to the natural insertion site (homing site) of the intron. The reverse splicing is independent of the homing endonuclease gene, but is dependent on the group I splicing ribozyme domain. The observed distribution of group I introns in nature can be explained by horizontal transfer between natural homing sites by reverse splicing and subsequent spread in populations by endonuclease-dependent homing.
Birgisdottir
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AB
Department of Molecular Biotechnology, Institute of Medical Biology, University of Tromsø, Tromsø, Norway.
Johansen
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SD
D000818:Animals; D001419:Bacteria / Q000235:genetics; D007438:Introns / Q000235:genetics*; D012326:RNA Splicing / Q000235:genetics*; D016337:RNA, Catalytic / Q000235:genetics*; D012335:RNA, Ribosomal / Q000235:genetics*; D015003:Yeasts / Q000235:genetics
D016337:RNA, Catalytic; D012335:RNA, Ribosomal