title: Remarkable sequence conservation of the last intron in the PKD1 gene.
abstract: The last intron of the PKD1 gene (intron 45) was found to have exceptionally high sequence conservation across four mammalian species: human, mouse, rat, and dog. This conservation did not extend to the comparable intron in pufferfish. Pairwise comparisons for intron 45 showed 91% identity (human vs. dog) to 100% identity (mouse vs. rat) for an average for all four species of 94% identity. In contrast, introns 43 and 44 of the PKD1 gene had average pairwise identities of 57% and 54%, and exons 43, 44, and 45 and the coding region of exon 46 had average pairwise identities of 80%, 84%, 82%, and 80%. Intron 45 is 90 to 95 bp in length, with the major region of sequence divergence being in a central 4-bp to 9-bp variable region. RNA secondary structure analysis of intron 45 predicts a branching stem-loop structure in which the central variable region lies in one loop and the putative branch point sequence lies in another loop, suggesting that the intron adopts a specific stem-loop structure that may be important for its removal. Although intron 45 appears to conform to the class of small, G-triplet-containing introns that are spliced by a mechanism utilizing intron definition, its high sequence conservation may be a reflection of constraints imposed by a unique mechanism that coordinates splicing of this last PKD1 intron with polyadenylation.
authors.affiliation: Department of Biochemistry and Molecular Biology, and the Kidney Institute, University of Kansas Medical Center, Kansas City, USA.
authors.forename: Marianna
authors.initials: M
authors.lastname: Rodova
authors.forename: M Rafiq
authors.initials: MR
authors.lastname: Islam
authors.forename: Kenneth R
authors.initials: KR
authors.lastname: Peterson
authors.forename: James P
authors.initials: JP
authors.lastname: Calvet
mesh_terms: D000818:Animals; D001483:Base Sequence; D017124:Conserved Sequence; D004285:Dogs; D006801:Humans; D007438:Introns; D051379:Mice; D009690:Nucleic Acid Conformation; D017354:Point Mutation; D011506:Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000737:chemistry; D051381:Rats; D050396:TRPP Cation Channels
chemical_list: D011506:Proteins; D012333:RNA, Messenger; D050396:TRPP Cation Channels