Self-splicing introns in tRNA genes of widely divergent bacteria

  title={Self-splicing introns in tRNA genes of widely divergent bacteria},
  author={Barbara Reinhold-Hurek and David. A. Shub},
THE organization of eukaryotic genes into exons separated by introns has been considered as a primordial arrangement1,2 but because it does not exist in eubacterial genomes it may be that introns are relatively recent acquisitions3. A self-splicing group I intron has been found in cyanobacteria at the same position of the same gene (that encoding leucyl transfer RNA, UAA anticodon) as a similar group I intron of chloroplasts4,5, which indicates that this intron predates the invasion of… 
Group II self-splicing introns in bacteria
The discovery of group II introns both in cyanobacteria and the γ subdivision of purple bacteria, or proteobacteria, whose α subdivision probably gave rise to mitochondria is reported, with at least one of these introns actually self-splices in vitro.
Origin and evolution of group I introns in cyanobacterial tRNA genes
The data support the notion that the tRNA(Leu)UAA intron was inherited by cyanobacteria and plastids through a common ancestor, and the t RNA(fMet) intron has a sporadic distribution, implying that many gains and losses occurred during cyanobacterial evolution.
Group I Self-Splicing Intron in the recA Gene of Bacillus anthracis
A group I intron is reported in the recA gene of Bacillus anthracis which was initially found by DNA sequencing as an intervening sequence (IVS) by using reverse transcriptase PCR, and the splicing was visualized in vitro with labeled free GTP, indicating that it is a group Iintron.
Large-scale tRNA intron transposition in the archaeal order Thermoproteales represents a novel mechanism of intron gain.
A newly identified mechanism that facilitates the late gain of short introns at various noncanonical positions in archaeal tRNAs is demonstrated, which suggests that frequent intron transposition occurs among the tRNA genes of Thermoproteales.
A Self-Splicing Group I Intron in DNA Polymerase Genes of T7-Like Bacteriophages
There is no barrier for maintenance of group I introns in phages of proteobacteria, and a self-splicing group I intron is inserted in the coding sequence of the DNA polymerase genes of PhiI and W31, phages that are closely related to T7.
Complex Evolutionary Patterns of tRNAUAALeu Group I Introns in Cyanobacterial Radiation
The results show that the evolution of the intron is considerably more complex than previous studies found to be the case and suggests differences in the phylogenetic trees for 16S rDNA and the tRNAUAALeu group I introns.
Molecular evidence for the antiquity of group I introns inter-rupting transfer RNA genes in cyanobacteria
This study provides convincing phylogenetic evidence that the tRNA group I intron subfamily is ancient and this means that these introns are between 2.1 and 3.5 billion years old.
21 tRNA Splicing: An RNA World Add-on or an Ancient Reaction?
Progress in understanding both eukaryotic and archaeal tRNA splicing has revealed that the two processes, previously thought to be unrelated, are in fact similar, and insight gained from the comparison has provided a clearer understanding of intron recognition, the catalysis of introns removal, and has given new insight into the evolution of the t RNA splicing process.
Unexpected abundance of self-splicing introns in the genome of bacteriophage Twort: introns in multiple genes, a single gene with three introns, and exon skipping by group I ribozymes.
  • M. Landthaler, D. Shub
  • Biology
    Proceedings of the National Academy of Sciences of the United States of America
  • 1999
A single ORF of 142 amino acids (Orf142) is interrupted by three self-splicing group I introns, providing the first example of a phage gene with multiple intron insertions.


An ancient group I intron shared by eubacteria and chloroplasts
The homology of the intron across chloroplasts and cyanobacteria implies that it was present in their common ancestor and that it has been maintained in their genomes for at least 1 billion years.
Bacterial origin of a chloroplast intron: conserved self-splicing group I introns in cyanobacteria
A self-splicing group I intron has been found in the gene for a leucine transfer RNA in two species of Anabaena, a filamentous nitrogen-fixing cyanobacterium, likely to predated the endosymbiotic association of these eubacteria with eukaryotic cells.
All human tRNATyr genes contain introns as a prerequisite for pseudouridine biosynthesis in the anticodon.
It is suggested that the evolutionary pressure for maintaining introns in eukaryotic tRNAsTyr is this strict intron-requirement for psi 35 synthesis, and a special need is discussed here for this modified nucleoside in stabilizing codon-anticodon interactions involving classical base pairing upon translation of tyrosine codons and unconventional interactions during UAG amber codon suppression by tRNATyrG psi A in eUKaryotic cells.
Pseudouridine modification in the tRNA(Tyr) anticodon is dependent on the presence, but independent of the size and sequence, of the intron in eucaryotic tRNA(Tyr) genes.
Results suggest that for appropriate function the psi 35 enzyme in the X. laevis oocyte needs the presence of an unqualified intron in the tRNA gene and a tRNA(Tyr)-like structure in the unprocessed tRNA precursor.