Group II introns are noncoding sequences that interrupt genes, and that must be removed or spliced-out at the RNA level during gene expression. Following the transcription of interrupted genes, group II introns self-splice while concurrently ligating their flanking exons to generate mature mRNAs ready for translation. Ll.LtrB, the model group II intron from the gram-positive bacterium Lactococcus lactis, interrupts the gene coding for a relaxase enzyme that initiates the transfer of mobile elements by conjugation. This functional link between group II intron splicing and conjugative transfer enabled us to engineer highly sensitive splicing assays using the native biological context of Ll.LtrB. The splicing efficiency/conjugation assay was developed to determine the splicing competence of various Ll.LtrB mutants, whereas the splicing selection/conjugation assay was established to isolate splicing-proficient variants from a randomly generated bank of mutated introns.
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http://dx.doi.org/10.1007/978-1-0716-0716-9_1 | DOI Listing |
A previous study found that a domesticated bacterial group II intron-like reverse transcriptase (G2L4 RT) functions in double-strand break repair (DSBR) via microhomology-mediated end joining (MMEJ) and that a mobile group II intron-encoded RT has a basal DSBR activity that uses conserved structural features of non-LTR-retroelement RTs. Here, we determined G2L4 RT apoenzyme and snap-back DNA synthesis structures revealing novel structural adaptations that optimized its cellular function in DSBR. These included a unique RT3a structure that stabilizes the apoenzyme in an inactive conformation until encountering an appropriate substrate; a longer N-terminal extension/RT0-loop with conserved residues that together with a modified active site favors strand annealing; and a conserved dimer interface that localizes G2L4 RT homodimers to DSBR sites with both monomers positioned for MMEJ.
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January 2025
University Museum, The University of Bergen, Postboks 7800, N-5020, Bergen, Norway The University of Bergen Bergen Norway.
Plant phylogenetics has been revolutionised in the genomic era, with target capture acting as the primary workhorse of most recent research in the new field of phylogenomics. Target capture (aka Hyb-Seq) allows researchers to sequence hundreds of genomic regions (loci) of their choosing, at relatively low cost per sample, from which to derive phylogenetically informative data. Although this highly flexible and widely applicable method has rightly earned its place as the field's standard, it does not come without its challenges.
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January 2025
Department of Hematology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China.
HLA-A*02:01:01:257 differs from HLA-A*02:01:01:01 by a single nucleotide substitution in intron 7.
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January 2025
Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA, USA.
While all native tRNAs undergo extensive post-transcriptional modifications as a mechanism to regulate gene expression, mapping these modifications remains challenging. The critical barrier is the difficulty of readthrough of modifications by reverse transcriptases (RTs). Here we use Induro-a new group-II intron-encoded RT-to map and quantify genome-wide tRNA modifications in Induro-tRNAseq.
View Article and Find Full Text PDFBiology (Basel)
January 2025
Biomedical Science Research Unit, Faculty of Medicine, Mahasarakham University, Maha Sarakham 44000, Thailand.
Urinary schistosomiasis is caused by the blood fluke , which is predominantly found in Africa. The freshwater snail is its main intermediate host. The species that make up the group are genetically complex, and their taxonomic status remains controversial.
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