Formation of an intermediate Spliceosomal C (Bact) complex

Stable Identifier
R-HSA-72130
Type
Reaction
Species
Homo sapiens
Compartment
Locations in the PathwayBrowser
Summation

The intermediate spliceosomal C complex (also called the Bact or B(act) complex) is a very short-lived intermediate; the splicing intermediates are rapidly converted to splicing products. Also, the spliced products are released very rapidly, and no complex containing both the splicing products has been isolated. Conversion of the spliceosomal B complex to the spliceosomal C complex requires ATP. The extensive base-pairing between the U4 and U6 snRNAs is disrupted during the formation of the C complex, which is thought to require helicase-type activity associated with the DEAD box factors. The U4 snRNP and U1 snRNP dissociate from the complex and the LSM2-6 complex of the U6 snRNP is lost, apparently allowing the U6 snRNA to then base-pair with the U2 snRNA and the 5' end of the splice site on the mRNA (Bessonov et al. 2010).

Literature References
PubMed ID Title Journal Year
12411573 Small nuclear ribonucleoprotein remodeling during catalytic activation of the spliceosome

Makarov, EM, Makarova, OV, Urlaub, H, Gentzel, M, Will, CL, Wilm, M, Lührmann, R

Science 2002
20980672 Characterization of purified human Bact spliceosomal complexes reveals compositional and morphological changes during spliceosome activation and first step catalysis

Bessonov, S, Anokhina, M, Krasauskas, A, Golas, MM, Sander, B, Will, CL, Urlaub, H, Stark, H, Lührmann, R

RNA 2010
2963332 Spliceosome assembly involves the binding and release of U4 small nuclear ribonucleoprotein

Lamond, AI, Konarska, MM, Grabowski, PJ, Sharp, PA

Proc. Natl. Acad. Sci. U.S.A. 1988
11991638 Purification and characterization of native spliceosomes suitable for three-dimensional structural analysis.

Jurica, MS, Licklider, LJ, Gygi, SR, Grigorieff, N, Moore, MJ

RNA 2002
12176931 Large-scale proteomic analysis of the human spliceosome.

Rappsilber, J, Ryder, U, Lamond, AI, Mann, M

Genome Res 2002
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