title: Conservation/Mutation in the Splice Sites of Mitochondrial Solute Carrier Genes of Vertebrates.
abstract: The "canonical" introns begin by the dinucleotide GT and end by the dinucleotide AG. GT, together with a few downstream nucleotides, and AG, with a few of the immediately preceding nucleotides, are thought to be the strongest splicing signals (5'ss and 3'ss, respectively). We examined the composition of the intronic initial and terminal hexanucleotides of the mitochondrial solute carrier genes (SLC25A's) of zebrafish, chicken, mouse, and human. These genes are orthologous and we selected the transcripts in which the arrangement of exons and introns was superimposable in the species considered. Both 5'ss and 3'ss were highly polymorphic, with 104 and 126 different configurations, respectively, in our sample. In the line of evolution from zebrafish to chicken, as well as in that from zebrafish to mammals, the average nucleotide conservation in the four variable nucleotides was about 50 % at 5' and 40 % at 3'. In the divergent evolution of mouse and human, the conservation was about 80 % at 5' and 70 % at 3'. Despite these changes, the splicing signals remain strong enough to operate at the same site. At both 5' and 3', the frequency of a nucleotide at a given position in the zebrafish sequence is positively correlated with its conservation in chicken and mammals, suggesting that selection continued to operate in birds and mammals along similar lines.
authors.affiliation: Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via Orabona, 4, 70126, Bari, Italy.
authors.forename: Rosa
authors.initials: R
authors.lastname: Calvello
authors.affiliation: Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via Orabona, 4, 70126, Bari, Italy. mariaantonietta.panaro@uniba.it.
authors.forename: Maria A
authors.initials: MA
authors.lastname: Panaro
authors.affiliation: Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via Orabona, 4, 70126, Bari, Italy.
authors.forename: Rosaria
authors.initials: R
authors.lastname: Salvatore
authors.affiliation: Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via Orabona, 4, 70126, Bari, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Mitolo
authors.affiliation: Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via Orabona, 4, 70126, Bari, Italy.
authors.forename: Antonia
authors.initials: A
authors.lastname: Cianciulli
mesh_terms: D000818:Animals; D027321:Anion Transport Proteins / Q000235:genetics*; D001483:Base Sequence; D002645:Chickens; D016384:Consensus Sequence; D019143:Evolution, Molecular; D005091:Exons; D050259:Genes, Mitochondrial; D006801:Humans; D007438:Introns; D051379:Mice; D024101:Mitochondrial Proteins / Q000235:genetics; D009154:Mutation; D009711:Nucleotides / Q000235:genetics; D022821:RNA Splice Sites; D012326:RNA Splicing; D014714:Vertebrates / Q000235:genetics*; D015027:Zebrafish
chemical_list: D027321:Anion Transport Proteins; D024101:Mitochondrial Proteins; D009711:Nucleotides; D022821:RNA Splice Sites
keywords: Chicken; Human; Mitochondrial solute carrier genes; Mouse; Splice sites; Zebrafish