Anti-SAP155/SF3b155 Antibody

Splicing factor 3B subunit 1 (UniProt O75533; also known as Pre-mRNA-splicing factor SF3b 155 kDa subunit, SAP 155, SF3b155, Spliceosome-associated protein 155) is encoded by the SF3B1 (also known as PRP10, PRPF10, SAP155) gene (Gene ID 23451) in human. SF3a and SF3b are multiprotein complexes required for the assembly of spliceosomal A complex. SF3a consists of three subunits (SF3a60/SAP 61, SF3a66/SAP 62, SF3a120/SAP 114) and SF3b consists of at least four subunits (SF3b50/SAP 49, SF3b130/SAP 130, SF3b145/SAP 145, and SF3b155/SAP 155). SF3a/b subunits cross-link to a 25-nucleotide region in the pre-mRNA located immediately upstream to the branchpoint sequence (BPS) and help anchor U2 snRNP to the BPS. SAP 155 is a critical component of the spliceosome active site. SAP 155 cross-links to pre-mRNA on both sides of the branch site and is thus strategically positioned over the branch-site adenosine before the nucleophilic attack on the 5′ splice site (ss) by the branch-site adenosine. SAP 155 is phosphorylated during splicing catalysis. SAP 155 phosphorylation is detected only in functional spliceosomes and phosphorylated SAP 155 contacts both sides of the branch site during catalysis.

This antiserum detected both phosphorylated and non-phosphorylated SAP 155/SF3b155 (Wang, C., et al. (1998). Genes Dev. 1998 12 1409-1414). Epitope is absent from spliced isoform 2 (UniProt O75533-2).

Epitope: PPP1R8-interacting domain.

Linear peptide corresponding to a sequence within the PPP1R8-interacting domain of human SAP155/SF3b155.

Anti-SAP155/SF3b155 Antibody is an antibody against SAP155/SF3b155 for use in Western Blotting, Immunoprecipitation.

Western Blotting Analysis: A representative lot detected SAP 155/SF3b155 in the H2A.Bbd chromatin immunoprecipitate, indicating an association of H2A.bbd nucleosomes with the Sf3b subcomplex required for assembling the U2 snRNP (Tolstorukov, M.Y., et al. (2012). Mol. Cell 47(4):596–607).
Western Blotting Analysis: A representative lot detected one SAP 155/SF3b155 immunoreactive band in the spliceosomal complex A/B and two SAP 155 immunoreactive bands in the spliceosomal complex C. The additional slower migrating band in complex C represents the phosphorylated form (Wang, C., et al. (1998). Genes Dev. 12(10):1409-1414).
Immunoprecipitation Analysis: A representative lot immunoprecipitated in vitro translated SAP 155/SF3b155 and co-immunoprecipitated U2 snRNP from nuclear extracts (Wang, C., et al. (1998). Genes Dev. 12(10):1409-1414).

Evaluated by Western Blotting in U2OS nuclear extract.

Western Blotting Analysis: An 1:500 dilution of this antibody detected SAP155/SF3b155 in 10 µg of U2OS nuclear extract.

~155 kDa observed. 145.8 kDa calculated. A doublet banding pattern with the upper band representing the phosphorylated form can be detected in functional spliceosomes assembled in vitro, but not in total nuclear extracts (Wang, C., et al. (1998). Genes Dev. 12(10):1409-1414).

Concentration: Please refer to lot specific datasheet.