title: Requirements for self-splicing of a group I intron from Physarum polycephalum.
abstract: The third intron from Physarum polycephalum (Pp LSU 3) is one of the closest known relatives to the well-studied Tetrahymena group I intron. Both introns are located at the same position in the 26S rRNA gene, and with the exception of an open reading frame in Pp LSU 3, are highly homologous. While Pp LSU 3 has been shown to self splice, little is known about its activity in vitro. We have examined the requirements for self splicing in greater detail. Despite its similarity to the Tetrahymena intron, Pp LSU 3 is 1500-fold less reactive, demonstrates a preference for high salt, and exhibits a low Km for GTP. Removal of the open reading frame results in a modest increase of activity. This system provides an opportunity to understand how sequence variations in two related introns alter the efficiency of autoexcision, and how this relates to adaptation of group I introns to their particular sequence context.
authors.affiliation: Department of Chemistry and Biochemistry, University of Maryland, College Park 20742-2021.
authors.forename: G A
authors.initials: GA
authors.lastname: Rocheleau
authors.forename: S A
authors.initials: SA
authors.lastname: Woodson
mesh_terms: D000818:Animals; D001483:Base Sequence; D005091:Exons; D017353:Gene Deletion; D006160:Guanosine Triphosphate / Q000378:metabolism; D007438:Introns; D007700:Kinetics; D015636:Magnesium Chloride / Q000494:pharmacology; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D016366:Open Reading Frames; D016839:Physarum polycephalum / Q000235:genetics*; D012322:RNA Precursors / Q000737:chemistry / Q000378:metabolism*; D012326:RNA Splicing; D013696:Temperature
chemical_list: D012322:RNA Precursors; D015636:Magnesium Chloride; D006160:Guanosine Triphosphate