Polyomavirus large T mutants affected in retinoblastoma protein binding are defective in immortalization

Larose, A., Dyson, N., Sullivan, M., Harlow, E., Bastin, M. (May 1991) Polyomavirus large T mutants affected in retinoblastoma protein binding are defective in immortalization. J Virol, 65 (5). pp. 2308-13. ISSN 0022-538X (Print)0022-538X (Linking)

URL: http://www.ncbi.nlm.nih.gov/pubmed/2016761


To clarify the relationship between the various activities of the polyomavirus large T antigen and the contribution of this oncogene to neoplastic transformation, we constructed a series of mutants with small deletions or single-amino-acid substitutions in two separate regions of the protein. These sequences were targeted because they showed considerable similarity to conserved regions 1 and 2 of adenovirus E1A which are thought to be binding sites for the retinoblastoma gene product (pRB). The pRB-binding properties of the large T mutants were assessed with an in vitro coimmunoprecipitation assay. pRB binding was readily detected with wild-type large T, but coprecipitation was completely abolished by as little as a single amino acid substitution (Asp-141----Glu or Glu-146----Asp) in region 2 of the polyomavirus large T antigen. Mutants defective in pRB binding were unable to immortalize primary rat embryo fibroblasts, suggesting that association with pRB is an important component of immortalization mediated by polyomavirus large T. The mutations in region 1 affected pRB binding only marginally, yet some of them severely impaired immortalization, indicating that pRB binding may be essential but not sufficient for immortalization.

Item Type: Paper
Uncontrolled Keywords: Amino Acid Sequence Animals Antigens, Polyomavirus Transforming/genetics/*metabolism Cell Transformation, Neoplastic/*metabolism *Cell Transformation, Viral Cells, Cultured Molecular Sequence Data Mutagenesis, Site-Directed Precipitin Tests Rats Retinoblastoma Protein/*metabolism
Subjects: diseases & disorders > cancer > cancer types > retinoblastoma
organism description > virus
CSHL Authors:
Communities: CSHL labs > Stillman lab
Depositing User: Matt Covey
Date: May 1991
Date Deposited: 21 Dec 2015 19:39
Last Modified: 21 Dec 2015 19:39
PMCID: PMC240580
Related URLs:
URI: https://repository.cshl.edu/id/eprint/32122

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