Description_x000D_ Biochem/physiol Actions_x000D_ ASF or called SF2, a member of the SR protein family, is an essential pre-mRNA splicing factor required for both single and alternative splicing. Phosphorylation on serine residues located within the SR domain directly regulates ASF/SF2 activity and compartmentalization of other SR splicing factors. In addition to interacting with RNA and other splicing factors, such as U1-70K, U2AF and other SR proteins, ASF/SF2 also directly or indirectly interacts with HIV regulatory protein Rev, the C-terminal domain (CTD) of the largest subunit of RNA polymerase II, and numerous transcription factors, thereby suggesting a potential role of ASF/SF2 in coordinating of transcription and pre-mRNA splicing._x000D_ Physical form_x000D_ Clear and colorless frozen liquid solution_x000D_ Preparation Note_x000D_ Use a manual defrost freezer and avoid repeated freeze-thaw cycles. While working, please keep sample on ice.