Trans-splicing is a process by which 5'- and 3'-ends of two pre-RNA molecules transcribed from different sites of the genome can be joined together to form a single RNA molecule. The spliced leader (SL) trans-splicing is mediated by the spliceosome and it allows the replacement of 5'-end of pre-mRNA by 5'(SL)-end of SL-RNA. This form of splicing has been observed in many phylogenetically unrelated eukaryotes. Either the SL trans-splicing (SLTS) originated in the last eukaryotic common ancestor (LECA) (or even earlier) and it was lost in most eukaryotic lineages, or this mechanism of RNA processing evolved several times independently in various unrelated eukaryotic taxa. The bioinformatic comparisons of SL-RNAs from various eukaryotic taxonomic groups have revealed the similarities of secondary structures of most SL-RNAs and a relative conservation of their splice sites (SSs) and Sm-binding sites (SmBSs). We propose that such structural and functional similarities of SL-RNAs are unlikely to have evolved repeatedly many times. Hence, we favor the scenario of an early evolutionary origin for the SLTS and multiple losses of SL-RNAs in various eukaryotic lineages.

• Klíčová slova
• Intron, RNA secondary structure, SL-RNA, Sm-binding site, Spliceosome,
• MeSH
• Eukaryota genetika   metabolismus   MeSH
• fylogeneze MeSH
• molekulární evoluce * MeSH
• prekurzory RNA metabolismus   MeSH
• RNA se sestřihovou vedoucí sekvencí genetika   metabolismus   MeSH
• trans-splicing * MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• prekurzory RNA MeSH
• RNA se sestřihovou vedoucí sekvencí MeSH

IRESite is an exhaustive, manually annotated non-redundant relational database focused on the IRES elements (Internal Ribosome Entry Site) and containing information not available in the primary public databases. IRES elements were originally found in eukaryotic viruses hijacking initiation of translation of their host. Later on, they were also discovered in 5'-untranslated regions of some eukaryotic mRNA molecules. Currently, IRESite presents up to 92 biologically relevant aspects of every experiment, e.g. the nature of an IRES element, its functionality/defectivity, origin, size, sequence, structure, its relative position with respect to surrounding protein coding regions, positive/negative controls used in the experiment, the reporter genes used to monitor IRES activity, the measured reporter protein yields/activities, and references to original publications as well as cross-references to other databases, and also comments from submitters and our curators. Furthermore, the site presents the known similarities to rRNA sequences as well as RNA-protein interactions. Special care is given to the annotation of promoter-like regions. The annotated data in IRESite are bound to mostly complete, full-length mRNA, and whenever possible, accompanied by original plasmid vector sequences. New data can be submitted through the publicly available web-based interface at http://www.iresite.org and are curated by a team of lab-experienced biologists.

• MeSH
• 5' nepřekládaná oblast chemie   MeSH
• databáze nukleových kyselin * MeSH
• iniciace translace peptidového řetězce * MeSH
• iniciační faktory metabolismus   MeSH
• internet MeSH
• messenger RNA chemie   MeSH
• plazmidy chemie   MeSH
• promotorové oblasti (genetika) MeSH
• regulační sekvence ribonukleových kyselin MeSH
• RNA virová chemie   MeSH
• uživatelské rozhraní počítače MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 5' nepřekládaná oblast MeSH
• iniciační faktory MeSH
• messenger RNA MeSH
• regulační sekvence ribonukleových kyselin MeSH
• RNA virová MeSH