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Updated: Aug 10, 2026

Inducible and Reversible Dominant-negative (DN) Protein Inhibition
08:35

Inducible and Reversible Dominant-negative (DN) Protein Inhibition

Published on: January 7, 2019

Dominant negative mutants of transcription factor mXBP (CRE-BP1, ATF-2)

L B Ivashkiv1, M D Fleming, L H Glimcher

  • 1Department of Cancer Biology, Harvard School of Public Health, Boston, MA 02115.

The New Biologist
|April 1, 1992
PubMed

Insights

Researchers investigated the function of mXBP, a transcription factor. They found that specific DNA-binding is crucial for mXBP to activate gene transcription, and identified dominant-negative mutants for further study.

Area of Science:

  • Molecular Biology
  • Genetics
  • Biochemistry

Background:

  • Transcription factors of the CREB/ATF family regulate gene expression by binding to cyclic AMP response elements (CREs).
  • While CREB function is well-studied, the roles of other family members, like mXBP (CRE-BP1, ATF-2), remain less understood.

Purpose of the Study:

  • To analyze the function of the transcription factor mXBP.
  • To identify the specific DNA-binding requirements for mXBP-mediated transcriptional activation.
  • To characterize dominant-negative mutants of mXBP for future research.

Main Methods:

  • Overexpression of mXBP in cells to assess its transcriptional activity.
  • Site-directed mutagenesis of the mXBP DNA-binding domain.
  • Analysis of DNA-binding affinity and transcriptional activation of CRE-containing promoters.

Main Results:

  • Overexpression of mXBP activated transcription from a promoter containing CREs.
  • Mutagenesis identified key residues in the mXBP DNA-binding domain essential for CRE binding.
  • Mutants unable to bind DNA failed to activate transcription and, in some cases, inhibited wild-type mXBP activity.

Conclusions:

  • Specific DNA binding is critical for mXBP's role in transcriptional activation.
  • mXBP functions as a transcription factor by binding to cyclic AMP response elements.
  • Generated dominant-negative mXBP mutants provide valuable tools for dissecting mXBP's in vivo functions.

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