A spliceosome is a large ribonucleoprotein (RNP) complex found primarily within the nucleus of eukaryotic cells. The spliceosome is assembled from small nuclear RNAs (snRNA) and numerous proteins. Small nuclear RNA (snRNA) molecules bind to specific proteins to form a small nuclear ribonucleoprotein complex, which in turn combines with other snRNPs to form a large ribonucleoprotein complex called a spliceosome. The spliceosome removes introns from a transcribed pre-mRNA, a type of primary transcript. This process is generally referred to as splicing. An analogy is a film editor, who selectively cuts out irrelevant or incorrect material from the initial film and sends the cleaned-up version to the director for the final cut.
The U4 small nuclear Ribo-Nucleic Acid is a non-coding RNA component of the major or U2-dependent spliceosome – a eukaryotic molecular machine involved in the splicing of pre-messenger RNA (pre-mRNA). It forms a duplex with U6, and with each splicing round, it is displaced from the U6 snRNA in an ATP-dependent manner, allowing U6 to re-fold and create the active site for splicing catalysis. A recycling process involving protein Brr2 releases U4 from U6, while protein Prp24 re-anneals U4 and U6. The crystal structure of a 5′ stem-loop of U4 in complex with a binding protein has been solved.
Splicing factor U2AF 65 kDa subunit is a protein that in humans is encoded by the U2AF2 gene.
Pre-mRNA-processing-splicing factor 8 is a protein that in humans is encoded by the PRPF8 gene.
PRP31 pre-mRNA processing factor 31 homolog , also known as PRPF31, is a protein which in humans is encoded by the PRPF31 gene.
Splicing factor 3 subunit 1 is a protein that in humans is encoded by the SF3A1 gene.
Pinin is a protein that in humans is encoded by the PNN gene.
U4/U6 small nuclear ribonucleoprotein Prp3 is a protein that in humans is encoded by the PRPF3 gene.
Splicing factor 3A subunit 3 is a protein that in humans is encoded by the SF3A3 gene.
U5 small nuclear ribonucleoprotein 200 kDa helicase is an enzyme that in humans is encoded by the SNRNP200 gene.
Splicing factor 3A subunit 2 is a protein that in humans is encoded by the SF3A2 gene.
Splicing factor 3B subunit 3 is a protein that in humans is encoded by the SF3B3 gene.
Pre-mRNA-processing factor 6 is a protein that in humans is encoded by the PRPF6 gene.
Serine/threonine-protein kinase PRP4 homolog is an enzyme that in humans is encoded by the PRPF4B gene.
Pre-mRNA-processing factor 17 is a protein that in humans is encoded by the CDC40 gene.
Peptidyl-prolyl cis-trans isomerase H is an enzyme that in humans is encoded by the PPIH gene.
Probable ATP-dependent RNA helicase DDX23 is an enzyme that in humans is encoded by the DDX23 gene.
Putative pre-mRNA-splicing factor ATP-dependent RNA helicase DHX15 is an enzyme that in humans is encoded by the DHX15 gene.
Prp24 is a protein part of the pre-messenger RNA splicing process and aids the binding of U6 snRNA to U4 snRNA during the formation of spliceosomes. Found in eukaryotes from yeast to E. coli, fungi, and humans, Prp24 was initially discovered to be an important element of RNA splicing in 1989. Mutations in Prp24 were later discovered in 1991 to suppress mutations in U4 that resulted in cold-sensitive strains of yeast, indicating its involvement in the reformation of the U4/U6 duplex after the catalytic steps of splicing.
Prp8 refers to both the Prp8 protein and Prp8 gene. Prp8's name originates from its involvement in pre-mRNA processing. The Prp8 protein is a large, highly conserved, and unique protein that resides in the catalytic core of the spliceosome and has been found to have a central role in molecular rearrangements that occur there. Prp8 protein is a major central component of the catalytic core in the spliceosome, and the spliceosome is responsible for splicing of precursor mRNA that contains introns and exons. Unexpressed introns are removed by the spliceosome complex in order to create a more concise mRNA transcript. Splicing is just one of many different post-transcriptional modifications that mRNA must undergo before translation. Prp8 has also been hypothesized to be a cofactor in RNA catalysis.
