Small nuclear ribonucleoprotein particle

Removal of introns. snRNP = small nuclear ribonucleoprotein particle. 

Birnstiel, M. L., ed. (1988) Small Nuclear Ribonucleoprotein Particles, Springer, Vienna/ New York... 

To assist in the modification and processing of mRNAs, eukaryotic cells contain in their nuclei small nuclear RNAs (snRNAs), which are complexed with specific proteins to form small nuclear ribonucleoprotein particles (snRNPs). These RNAs have been named U1, U2, U3,.. . , U13 and range in size from 100 to 220 bases. One, U3, is... 

B1. Bachmann, M., Falke, D., Schroder, H. C., and Muller, W. E., Intracellular distribution of the La antigen in CV-1 cells after herpes simplex virus type 1 infection compared with the localization of U small nuclear ribonucleoprotein particles. J. Gen. Virol. 70, 881-891 (1989). 

The small nuclear ribonucleoprotein particles (snRNPs or snurps ) that carry out the splicing reaction use RNA-RNA basepairing to select the splice sites. Almost all intron-exon junctions contain the sequence AG-GU with the GU beginning the intron sequence. Furthermore, the consensus sequence for the beginning of the intron has a longer sequence complementary to the U1 RNA. Thus, assembly of the splicing complex, called the spliceosome, starts when the RNA component of the U1 snRNP base pairs with the junction between the 3 end of the exon and the 5 end of the intron. See Figure 12-13. 

Table 11.4 Small Nuclear Ribonucleoprotein Particles (snRNP) in Splicing of mRNA Precursors...

Small nuclear ribonucleoprotein particle Soil organic carbon store-operated channel Suppressors of cytokine signaling Superoxide dismutase CuZn-SOD enzyme (intracellular)... 

D, Keller W. Functions of the abundant U-snRNPs. In Small Nuclear Ribonucleoprotein Particles. Birnstiel ML, ed. 1988. Springer-Verlag, Berlin. 53. 

Pikielny CW, Rosbash M. Specific small nuclear RNAs are associated with yeast spliceosomes. Cell 1986 45 869-877. Frendewey D, Kramer A, Keller W. Different small nuclear ribonucleoprotein particles are involved in different steps of splicing complex formation. Cold Spring Harb. Symp. Quant. Biol. 1987 52 287-298. 

Grabowski PJ, Sharp PA. Affinity chromatography of splicing 82. complexes U2, U5, and U4 + U6 small nuclear ribonucleoprotein particles in the spliceosome. Science 1986 233 1294-1299. 

Table 28.3. Small nuclear ribonucleoprotein particles (snRNPs) in the splicing of mRNA precursors...

The splicing of mRNA precursors is carried out by spliceosomes, which consist of small nuclear ribonucleoprotein particles (snRNPs). Splice sites in mRNA precursors are specified by sequences at ends of introns and by branch sites... 

H. Stark, P. Duhe, R. Luhrmann, and B. Kastner. 2001. Arrangement of RNA and proteins in the spliceosomal U1 small nuclear ribonucleoprotein particle Nature 409 539-542. (PuhMed)... 

Most striking is the splicing of mRNA precursors, which is catalyzed by spliceosomes consisting of small nuclear ribonucleoprotein particles (snRNPs). The small nuclear RNA (snRNA) molecules in these complexes play a key role in directing the alignment of splice sites and in mediating catalysis. Indeed, some RNA molecules can splice themselves in the absence of protein. This landmark discovery by Thomas Cech and Sidney Altman revealed that RNA molecules can serve as catalysts and greatly influenced our view of molecular evolution. 

Jamison, S.F. and Garcia, B.M. (1992). An ATP-independent U2 small nuclear ribonucleoprotein particle/precursor mRNA complex requires both splice sites and the polypyrimidine tract. Proc. Natl. Acad. Sci. USA 89, 5482-5486. 

Hausner, T.-P., Giglio, L. M. and Weiner, A. M. (1990) Evidence for base-pairing between mammalian U2 and U6 small nuclear ribonucleoprotein particles. Genes Dev. 4 2146 2156. 

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