Two distinct and frequently mutated regions of retinoblastoma protein are required for binding to SV40 T antigen.

摘要: The retinoblastoma susceptibility gene (RB) encodes a phosphoprotein of 110 kd (pp110RB) that forms specific complexes with SV40 T antigen and the transforming proteins several other DNA tumor viruses. Interaction RB is thought to contribute transformation by these viruses as demonstrated genetic analyses. To help understand function interactions, regions are involved in binding have been mapped. An vitro protein synthesis system capable producing full-length has developed facilitate mapping study. A 5- 10-fold increase translational efficiency reticulocyte lysate was obtained when 5' non-coding region mRNA replaced beta-globin or plant viral RNA, alfalfa mosaic virus (AMV) RNA4. series mutated polypeptides produced from this were assayed for binding. Two non-contiguous protein, amino acid residues 394-571 649-773, found be necessary T: mutations either abolished T-RB complex formation. These results consistent finding that, all cases analyzed so far, human cells also failed bind due deletions including at least one two required regions. Thus defined interaction might physiologically relevant well, play fundamental role normal function.