Novel Group I Intron in the tRNA ^Leu (UAA) Gene of a γ-Proteobacterium Isolated from a Deep Subsurface Environment

Abstract

A group I intron has been found to interrupt the anticodon loop of the tRNA Leu (UAA) gene in a bacterium belonging to the ␥-subdivision of Proteobacteria and isolated from a deep subsurface environment. The subsurface isolate SMCC D0715 was identified as belonging to the genus Pseudomonas. The group I intron from this isolate is the first to be reported for ␥-proteobacteria, and the first instance of a tRNA Leu (UAA) group I intron to be found in a group of bacteria other than cyanobacteria. The 231-nucleotide (nt) intron's sequence has group I conserved elements and folds into a bona fide group I secondary structure with canonical base-paired segments P1 to P9 and a paired region, P10. The D0715 intron possesses the 11-nt motif CCUACG . . . UAUGG in its P8 region, a feature not common in bacterial introns. To date, phylogenetic analysis has shown that bacterial introns form two distinct families, and their complex distribution suggests that both lateral transfer and common ancestry have taken part in the evolutionary history of these elements.

Mobile Elements in a Single-Filament Orange Guaymas Basin Beggiatoa (“Candidatus Maribeggiatoa”) sp. Draft Genome: Evidence for Genetic Exchange with Cyanobacteria

“…The first selfsplicing bacterial intron discovered was in the anticodon loop of a cyanobacterial tRNA-Leu-TAA (40,41), and introns in this tRNA are widespread among cyanobacteria and chloroplasts (e.g., see references 42 and 43). At least one has been found in a gammaproteobacterium (44). Group I introns have also been identified in the tRNA-Arg-CCT of several alphaproteobacteria (45,46), tRNA-Ile-CAT of a betaproteobacterium (45), and tRNA-fMet of some cyanobacteria (47).…”

Analysis of the composition of bacterial communities in oil reservoirs from a southern offshore Brazilian basin

“…Amongst these, Acinetobacter was the most abundant and it has been recognized in the literature as an aerobic degrader of hydrocarbon and lipids (Bach et al 2003;Pleshakova et al 2001;Sugimori et al 2002). In the phylogenetic tree, the clone bo22A03b was shown to be related to A. lwofii, Acinetobacter baumannii, Acinetobacter calcoaceticus and to one unidentified Acinetobacter strain from deep subsurface environment (Vepritskiy et al 2002). According to Barkovskii and Shub (1986) A. calcoaceticus is able to degrade a dense spectrum of aromatic compounds.…”

Repeat-type distribution in trnL intron does not correspond with species phylogeny: comparison of the genetic markers 16S rRNA and trnL intron in heterocystous cyanobacteria

“…The UAA anticodon of the tRNA Leu gene is, in many cyanobacteria, interrupted by two copy types of group I introns, type I containing the introns of chloroplasts (e.g. Kuhsel et al, 1990;Xu et al, 1990;Paquin et al, 1997;Strehl et al, 1999;Besendahl et al, 2000) and type II the eubacterial introns (Rudi & Jakobsen, 2002;Vepritskiy et al, 2002). The type I tRNA Leu UAA intron (trnL intron), which is present only as one sequence type in each cyanobacterial strain , has been used in taxonomic and ecological studies of cyanobacteria.…”