Search results for "Group I catalytic intron"
showing 4 items of 4 documents
A chimeric ribozyme in Clostridium difficile combines features of group I introns and insertion elements
2002
CdlSt1, a DNA insertion of 1975 bp, was identified within tcdA-C34, the enterotoxin gene of the Clostridium difficile isolate C34. Located in the catalytic domain A1-C34, Cd/St1 combines features of two genetic elements. Within the first 434 nt structures characteristic for group I introns were found; encoding the two transposase-like proteins tlpA and tlpB nucleotides 435-1975 represent the remainder of a IS605-like insertion element. We show that the entire CdlSt1 is accurately spliced from tcdA-C34 primary transcripts and that purified TcdA-C34 toxin is of regular size and catalytic activity. A search for CdlSt1-related sequences demonstrates that the element is widespread in toxinogenic…
The mitochondrial genome of fission yeast: inability of all introns to splice autocatalytically, and construction and characterization of an intronle…
1991
In this paper we report the inability of four group I introns in the gene encoding subunit I of cytochrome c oxidase (cox1) and the group II intron in the apocytochrome b gene (cob) to splice autocatalytically. Furthermore we present the characterization of the first cox1 intron in the mutator strain anar-14 and the construction and characterization of strains with intronless mitochondrial genomes. We provide evidence that removal of introns at the DNA level (termed DNA splicing) is dependent on an active RNA maturase. Finally we demonstrate that the absence of introns does not abolish homologous mitochondrial recombination.
Suitability of chloroplast LSU rDNA and its diverse group I introns for species recognition and phylogenetic analyses of lichen-forming Trebouxia alg…
2009
To date, species identification of lichen photobionts has been performed principally on the basis of microscopic examinations and molecular data from nuclear-encoded genes. In plants, the chloroplast genome has been more readily exploited than the nuclear genome for systematic investigations. At the present time, very little information is available about the chloroplast genome of lichen-forming algae. For this reason, we have sequenced a portion of the gene encoding for the chloroplast large sub-unit rRNA (LSU rDNA) as a new molecular marker. Sequencing of the chloroplast LSU rDNAs revealed the existence of an unusual diversity of group I introns (a total of 31) within 15 analyzed Trebouxi…
Conservation of the positions of metazoan introns from sponges to humans
2002
Abstract Sponges (phylum Porifera) are the phylogenetic oldest Metazoa still extant. They can be considered as reference animals (Urmetazoa) for the understanding of the evolutionary processes resulting in the creation of Metazoa in general and also for the metazoan gene organization in particular. In the marine sponge Suberites domuncula , genes encoding p38 and JNK kinases contain nine and twelve introns, respectively. Eight introns in both genes share the same positions and the identical phases. One p38 intron slipped for six bases and the JNK gene has three more introns. However, the sequences of the introns are not conserved and the introns in JNK gene are generally much longer. Intron…