page_title: U6 spliceosomal RNA
section_title: Secondary structure
hierarchical_section_title: U6 spliceosomal RNA / Secondary structure
caption_attribution_description: English: A schematic of the U4/U6 snRNA complex.
context_page_description: U6 snRNA is the non-coding small nuclear RNA component of U6 snRNP, an RNA-protein complex that combines with other snRNPs, unmodified pre-mRNA, and various other proteins to assemble a spliceosome, a large RNA-protein molecular complex that catalyzes the excision of introns from pre-mRNA. Splicing, or the removal of introns, is a major aspect of post-transcriptional modification and takes place only in the nucleus of eukaryotes.
  The RNA sequence of U6 is the most highly conserved across species of all five of the snRNAs involved in the spliceosome, suggesting that the function of the U6 snRNA has remained both crucial and unchanged through evolution.
  It is common in vertebrate genomes to find many copies of the U6 snRNA gene or U6-derived pseudogenes. This prevalence of "back-ups" of the U6 snRNA gene in vertebrates further implies its evolutionary importance to organism viability.
  The U6 snRNA gene has been isolated in many organisms, including C. elegans. Among them, baker's yeast is a commonly used model organism in the study of snRNAs.
  The structure and catalytic mechanism of U6 snRNA resembles that of domain V of group II introns.
context_section_description: While the putative secondary structure consensus base pairing is confined to a short 5' stem-loop, much more extensive structures have been proposed for specific organisms such as in yeast. In addition to the 5' stem loop, all confirmed U6 snRNAs can form the proposed 3' intramolecular stem loop.
  The U6 snRNA is known to form an extensive base-pair interactions with U4 snRNA. This interaction has been shown to be mutually exclusive to that of the 3' intramolecular stem loop.
caption: U4/U6 snRNA complex
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