Description
PRB, the product of retinoblastoma susceptibility gene RB-1, is one of the best-studied tumor suppressor gene products. At least two other pRB-related proteins, p107 and p130, have been identified and characterized. Mutations in RB-1 gene are often associated with the occurrence of various tumors. The activity of pRB is regulated through phosphorylation in a cell cycle-dependent manner. The hyperphosphorylated RB protein usually associates with the cell nucleus and binds transcription factors of E2F family. pRB represses transcription of its target genes, such as cdc2, cyclin A, and oncogene c-myc, c-fos through the binding with E2F factors and thereby regulating cell proliferation. The wild type pRB (residue1-928) is expressed in baculovirus system and purified by an affinity column in combination with FPLC chromatography. Purified protein is greater than 95% homogeneous and contains no detectable proteases, DNase, and RNase activity