There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.
Abstract
A cellular phosphoprotein with an apparent molecular mass of 90 kd (p90) that forms
a complex with both mutant and wild-type p53 protein has been characterized, purified,
and identified. The protein was identified as a product of the murine double minute
2 gene (mdm-2). The mdm-2 gene enhances the tumorigenic potential of cells when it
is overexpressed and encodes a putative transcription factor. To determine if mdm-2
could modulate p53 transactivation, a p53-responsive element from the muscle creatine
kinase gene was employed. A wild-type p53-expressing plasmid enhanced the expression
of the p53-responsive element when cotransfected into cells that contain no endogenous
p53. When a cosmid expressing mdm-2 was transfected with this p53-expressing plasmid,
the transactivation of the p53-responsive element was inhibited. Thus, a product of
the mdm-2 oncogene forms a tight complex with the p53 protein, and the mdm-2 oncogene
can inhibit p53-mediated transactivation.