U5 spliceosomal RNA explained

U5 spliceosomal RNA
Symbol:	U5
Rfam:	RF00020
Rna Type:	Gene snRNA; splicing
Tax Domain:	Eukaryota

U5 snRNA is a small nuclear RNA (snRNA) that participates in RNA splicing as a component of the spliceosome. It forms the U5 snRNP (small nuclear ribonucleoprotein) by associating with several proteins including Prp8 - the largest and most conserved protein in the spliceosome, Brr2 - a helicase required for spliceosome activation, Snu114, and the 7 Sm proteins.^[1] U5 snRNA forms a coaxially-stacked series of helices that project into the active site of the spliceosome.^{[2] [3]} Loop 1, which caps this series of helices, forms 4-5 base pairs with the 5'-exon during the two chemical reactions of splicing.^{[4] [5]} This interaction appears to be especially important during step two of splicing, exon ligation.^[6]

Further reading

• Zwieb C . The uRNA database . Nucleic Acids Research . 25 . 1 . 102–3 . January 1997 . 9016512 . 146409 . 10.1093/nar/25.1.102 .
• Thomas J, Lea K, Zucker-Aprison E, Blumenthal T . The spliceosomal snRNAs of Caenorhabditis elegans . Nucleic Acids Research . 18 . 9 . 2633–42 . May 1990 . 2339054 . 330746 . 10.1093/nar/18.9.2633 .

Notes and References

1. Stevens SW, Barta I, Ge HY, Moore RE, Young MK, Lee TD, Abelson J . Biochemical and genetic analyses of the U5, U6, and U4/U6 x U5 small nuclear ribonucleoproteins from Saccharomyces cerevisiae . RNA . 7 . 11 . 1543–53 . November 2001 . 11720284 . 1370197 .
2. Nguyen TH, Galej WP, Bai XC, Savva CG, Newman AJ, Scheres SH, Nagai K . The architecture of the spliceosomal U4/U6.U5 tri-snRNP . Nature . 523 . 7558 . 47–52 . July 2015 . 26106855 . 4536768 . 10.1038/nature14548 . 2015Natur.523...47N .
3. Yan C, Hang J, Wan R, Huang M, Wong CC, Shi Y . Structure of a yeast spliceosome at 3.6-angstrom resolution . Science . 349 . 6253 . 1182–91 . September 2015 . 26292707 . 10.1126/science.aac7629 . 2015Sci...349.1182Y . 22194712 .
4. Newman AJ, Norman C . U5 snRNA interacts with exon sequences at 5' and 3' splice sites . Cell . 68 . 4 . 743–54 . February 1992 . 1739979 . 10.1016/0092-8674(92)90149-7. 3328508 .
5. Sontheimer EJ, Steitz JA . The U5 and U6 small nuclear RNAs as active site components of the spliceosome . Science . 262 . 5142 . 1989–96 . December 1993 . 8266094 . 10.1126/science.8266094. 1993Sci...262.1989S .
6. O'Keefe RT, Norman C, Newman AJ . The invariant U5 snRNA loop 1 sequence is dispensable for the first catalytic step of pre-mRNA splicing in yeast . Cell . 86 . 4 . 679–89 . August 1996 . 8752221 . 10.1016/s0092-8674(00)80140-3. 17484887 . free .