mouse monoclonal IgG1; SR Antibody (1H4) is an IgG1 κ mouse monoclonal SR antibody (also designated pan SR antibody, pan Serine/Arginine-Rich Splicing Factor antibody, pan Splicing Component antibody, SRSF1 antibody, SR Splicing Factor 1 antibody, SRSF2 antibody, SR Splicing Factor 2 antibody, SRSF3 antibody, SR Splicing Factor 3 antibody, SRSF4 antibody, SR Splicing Factor 4 antibody, SRSF5 antibody, SR Splicing Factor 5 SRSF6 antibody, SR Splicing Factor 7 antibody, Splicing Component 75 KDa antibody, SRp75 antibody, Splicing Component 55 KDa antibody, SRp55 antibody, Splicing Component 40 KDa antibody, SRp40 antibody, Splicing Component 30 KDa antibody, SRp30a/b antibody, Splicing Component 20 KDa antibody, or SRp20 antibody) that detects the SR protein of human and Xenopus laevis origin by WB, IP, IF, IHC(P) and ELISA. SR Antibody (1H4) is available as both the non-conjugated anti-SR antibody form, as well as multiple conjugated forms of anti-SR 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.