mouse monoclonal IgG1; SRp20 Antibody (7B4) is an IgG1 mouse monoclonal SRp20 antibody (also designated Serine And Arginine Rich Splicing Factor 3 antibody, Splicing Factor Arginine/Serine-Rich 3 antibody, Serine/Arginine-Rich Splicing Factor 3 antibody, Pre-MRNA-Splicing Factor antibody, Splicing Factor Arginine/Serine-Rich 20-KD antibody, Pre-MRNA Splicing Factor SRp20 antibody, or SRP20 antibody) that detects the SRp20 protein of mouse, rat, human and avian origin by WB, IP and IF. SRp20 Antibody (7B4) is available as both the non-conjugated anti-SRp20 antibody form, as well as multiple conjugated forms of anti-SRp20 antibody, including agarose, HRP, PE, FITC and multiple Alexa Fluor® conjugates. Pre-mRNA splicing enhancer elements are short RNA sequences capable of activating weak splice sites in nearby introns that are required for accurate splice site recognition and the control of alternative splicing. Splicing enhancer elements contain specific binding sites for serine/arginine (SR)-rich splicing factors, which include SC35, 9G8, SRp20, and SF2/ASF. The family of SR factors all contain one or more RNA recognition motifs (RRM) and an arginine/ serine (RS)-rich domain. They are not only essential for constitutive splicing but also regulate splicing in a concentration-dependent manner by influencing the selection of alternative splice sites. The majority of SR proteins, including SC35 and SRp40, are confined to the nucleus, while SF2/ASF, SRp20, and 9G8 are continuously shuttled between the nucleus and the cytoplasm and contribute to mRNA transport. The activity of SR proteins in regulated splicing is antagonized by members of the hnRNP A/B family of proteins, which induce drastic shifts in the selection of splicing sites. An additional SR-associated protein, p32, tightly associates with SR factors and preferentially inhibits ASF/SF2 functioning as both a splicing enhancer and splicing repressor protein by preventing the stable interaction of ASF/SF2 and RNA.