ErbB3-binding protein EBP1 decreases ErbB2 levels via a transcriptional mechanism

  • Authors:
    • Arundhati Ghosh
    • Smita Awasthi
    • Anne W. Hamburger
  • View Affiliations

  • Published online on: December 14, 2012     https://doi.org/10.3892/or.2012.2186
  • Pages: 1161-1166
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Abstract

Ectopic expression of EBP1, an ErbB3-interacting protein, reduces the expression of the ErbB2 protein and mRNA. However, the mechanism of EBP1-induced decrease in ErbB2 mRNA levels has not yet been determined. Since EBP1 affects both transcriptional and post-transcriptional processes, we evaluated the ability of EBP1 to regulate ErbB2 transcription and RNA stability. We discovered that while wild-type EBP1 decreased the activity of a proximal ErbB2 promoter, EBP1 mutants unable to interact with the Sin3A transcriptional repressor inhibited activity to a lesser extent. EBP1 also decreased the activity of distal ErbB2 promoters. Chromatin immunoprecipitation analysis indicated that EBP1 bound both distal and proximal endogenous ErbB2 promoters in serum-starved conditions. The ErbB3 ligand heregulin (HRG) at growth-promoting concentrations reduced EBP1 binding to the ErbB2 promoter. Although endogenous EBP1 bound ErbB2 mRNA, EBP1 overexpression or ablation of EBP1 protein by shRNA failed to alter ErbB2 mRNA stability. These results suggest that the major effect of EBP1 on ErbB2 mRNA levels is at the transcriptional level.
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March 2013
Volume 29 Issue 3

Print ISSN: 1021-335X
Online ISSN:1791-2431

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Spandidos Publications style
Ghosh A, Awasthi S and Hamburger AW: ErbB3-binding protein EBP1 decreases ErbB2 levels via a transcriptional mechanism. Oncol Rep 29: 1161-1166, 2013
APA
Ghosh, A., Awasthi, S., & Hamburger, A.W. (2013). ErbB3-binding protein EBP1 decreases ErbB2 levels via a transcriptional mechanism. Oncology Reports, 29, 1161-1166. https://doi.org/10.3892/or.2012.2186
MLA
Ghosh, A., Awasthi, S., Hamburger, A. W."ErbB3-binding protein EBP1 decreases ErbB2 levels via a transcriptional mechanism". Oncology Reports 29.3 (2013): 1161-1166.
Chicago
Ghosh, A., Awasthi, S., Hamburger, A. W."ErbB3-binding protein EBP1 decreases ErbB2 levels via a transcriptional mechanism". Oncology Reports 29, no. 3 (2013): 1161-1166. https://doi.org/10.3892/or.2012.2186