Related Experiment Video
Updated: May 12, 2026

Methods to Discover Alternative Promoter Usage and Transcriptional Regulation of Murine Bcrp1
Published on: May 27, 2016
Regulation of the MDR1 promoter by E2F1 and EAPP
Peter Andorfer1, Hans Rotheneder
1Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, A-1030 Vienna, Austria.
Abstract:
Multidrug resistance (MDR), one of the main reasons for diminishing efficacy of prolonged chemotherapy, is frequently caused by the elevated expression of the ABCB1/MDR1 gene encoding PGP (P-glycoprotein). EAPP (E2F Associated PhosphoProtein) is a frequently overexpressed protein in human tumor cells. It inhibits apoptosis in a p21-dependent manner. We show here that EAPP stimulates the MDR1 promoter resulting in higher PGP levels. Independently of EAPP, E2F1 also increases the activity of the MDR1 promoter. Co-expression of pRb inhibits E2F1-, but not EAPP-dependent promoter activation. The upregulation of PGP might contribute to the survival of tumor cells during chemotherapy and worsen the prognosis for the patient.
Related Concept Videos
Master Transcription Regulators
Abnormal Proliferation
The Eukaryotic Promoter Region
The Eukaryotic Promoter Region
Negative Regulator Molecules
RNA Polymerase II Accessory Proteins

