@celineh2ooo.bsky.social and @stevensalzberg.bsky.social compared 3,493 vertebrate genomes to identify 342 gains of introns in human genes, tracing their origins and identifying cases of intronization as a mechanism of intron emergence.
🔗 doi.org/10.1093/gbe/evaf091
Specialized transposable elements capable of generating introns, termed introners, are one of the major drivers of intron gain in eukaryotes. Horizontal gene transfer (HGT) is thought to play an important role in shaping introner distributions. Viruses could function as vehicles of introner HGT since they often integrate into host genomes and have been implicated in widespread HGT in eukaryotes. We annotated integrated viral elements in diverse dinoflagellate genomes with active introners and queried viral elements for introner sequences. We find that 25% of viral elements contain introners. The vast majority of viral elements represent maverick-polinton-like double-stranded DNA (dsDNA) viruses as well as giant dsDNA viruses. By querying a previously annotated set of maverick-polinton-like proviruses, we show that introners populate full-length elements with machinery required for transposition as well as viral infection. Introners in the vast majority of viral elements are younger than or similar in age to others in their host genome, suggesting that most viral elements acquired introners after integration. However, a subset of viral elements show the opposite pattern wherein viral introners are significantly older than other introners, possibly consistent with virus-to-host horizontal transfer. Together, our results suggest that dsDNA viruses may serve as vectors for HGT of introners between individuals and species, resulting in the introduction of intron-generating transposons to new lineages. ### Competing Interest Statement R.C.-D. was supported by R35GM128932.
When your body turns your DNA into one of many alternate protein forms, it uses this finely tuned biomachinery for a rope dance with the mRNA strand to carry out very coordinated cuts and joins.
Absolutely incredible to see it animated with this level of detail :0
#RNA #spliceosome #structuralbiology #animation #exons #introns #alessoninthelariat
"Most importantly, by proving that the evolutionarily-conserved RNA core of splicing machines can recognize small molecules specifically, our work provides a solid basis for the rational design of splicing modulators not only against bacterial and organellar introns, but also against the human spliceosome, which is a validated drug target for the treatment of congenital diseases and cancers." #spliceosome #splicing #intron #introns #transcription #ribonucleicAcid #RNA
Splicing is a vital biological reaction and a druggable pathway to treat infection, genetic diseases and cancer. Here, the authors describe how splicing is modulated by small molecules that target the conserved splicing active site in the group II introns.
Scientists reveal how #RNA gets #spliced correctly.
https://phys.org/news/2023-11-scientists-reveal-rna-spliced.html
Pictures Considered #58: Visualizing Introns
by Christoph
By reading sequences we easily detect stretches that code for proteins. We detect promoters, transcription factor binding motifs, start/stop signals for transcription, signals where introns are removed by splicing from primary transcripts (pre‑mRNA) to yield mature messenger RNA (mRNA), and much more. It wasn't always so easy.
Read more → https://tinyurl.com/4s5zebxr
Researchers reveal structural mechanism of #Tetrahymena #ribozyme self-#splicing reaction.
https://phys.org/news/2023-04-reveal-mechanism-tetrahymena-ribozyme-self-splicing.html
A team led by Prof. Zhang Kaiming from the University of Science and Technology (USTC) solved six conformations in the second-step self-splicing of Tetrahymena ribozyme using cryogenic electron microscopy (cryo-EM), revealing the mechanism of group 1 introns coordinating self-splicing reactions. Their work was published in Nature Communications.
A New Model Offers an Explanation For The Huge Variety of Sizes of DNA in Nature:
A new model offers a possible solution to the scientific question of why neutral sequences, sometimes referred to as 'junk DNA', are not eliminated from the genome of living creatures in nature and continue to exist within it even millions of years later
https://royalsocietypublishing.org/doi/10.1098/rsob.220223
#genetics #genetic #molecularbiology #cellbiology #introns #dna
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