title: Purification of acetyl-p53 using p300 co-infection and the baculovirus expression system.
abstract: As cells persist in their environment, they are exposed to harmful agents that can damage their genomic DNA. When DNA becomes damaged, p53, a tumor suppressor, is stabilized and acts as a transcription factor to cause either cell cycle arrest or apoptosis. Strict p53 regulatory mechanisms have been well characterized relative to phosphorylation and dephosphorylation, but acetylation of p53 in response to DNA damage has also been shown to participate in p53 function. Proper investigation of the many roles that acetylated p53 plays in the cell requires accurate in vitro studies, which can only be easily conducted if highly pure acetyl-p53 is available. Purified p53 that is acetylated in vitro can routinely achieve 10-20%. Separating this acetylated fraction from the undesired unacetylated fraction can be technically challenging, inefficient, and time consuming. We have developed an in vivo strategy to rapidly produce microgram quantities of p53 preparations that are greater than 60% acetylated using co-infection of p53 and p300 baculoviruses in Sf21 insect cell culture. Immunoaffinity recovery followed by further depletion of unacetylated p53 results in a preparation that is greater than 70-75% in acetyl-p53 after a single round, and undetectable levels of unacetylated p53 after two rounds. This approach to preparing acetylated protein in vivo may also extend to other acetylated transcription factors and histones.
authors.affiliation: Department of Biochemistry, University of California, Riverside CA 92521, USA.
authors.forename: Landon G
authors.initials: LG
authors.lastname: Piluso
authors.forename: Gang
authors.initials: G
authors.lastname: Wei
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Li
authors.forename: Xuan
authors.initials: X
authors.lastname: Liu
mesh_terms: D000107:Acetylation; D000818:Animals; D016367:Baculoviridae / Q000235:genetics*; D002460:Cell Line; D002846:Chromatography, Affinity; D003001:Cloning, Molecular / Q000379:methods*; D009687:Nuclear Proteins / Q000235:genetics* / Q000302:isolation & purification; D018411:Spodoptera / Q000166:cytology; D015534:Trans-Activators / Q000235:genetics* / Q000302:isolation & purification; D014162:Transfection; D016159:Tumor Suppressor Protein p53 / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D009687:Nuclear Proteins; D015534:Trans-Activators; D016159:Tumor Suppressor Protein p53