Related Experiment Video

Updated: Aug 8, 2026

Identification of MyoD Interactome Using Tandem Affinity Purification Coupled to Mass Spectrometry
14:47

Identification of MyoD Interactome Using Tandem Affinity Purification Coupled to Mass Spectrometry

Published on: May 17, 2016

Functional domains of c-myc promoter binding protein 1 involved in transcriptional repression and cell growth

A K Ghosh1, R Steele, R B Ray

  • 1Department of Pathology, Saint Louis University, St. Louis, Missouri 63104, USA.

Molecular and Cellular Biology
|March 19, 1999
PubMed

Insights

Cervical carcinoma protein MBP-1 (c-myc promoter binding protein 1) regulates cell death and growth. Its N- and C-terminal domains repress transcription, with leucine residues in an LXVXL motif being crucial for this activity and cell growth suppression.

Area of Science:

  • Molecular Biology
  • Cancer Research
  • Cell Biology

Background:

  • c-myc promoter binding protein 1 (MBP-1) was identified as a negative regulator of c-myc promoter activity.
  • MBP-1 has demonstrated biological roles including induction of cell death and suppression of malignant characteristics in cancer cells.

Purpose of the Study:

  • To investigate the role of MBP-1 as a transcriptional regulator.
  • To identify the specific domains within MBP-1 responsible for transcriptional regulation.
  • To elucidate the structural motifs essential for MBP-1's repressor activity.

Main Methods:

  • Construction of a chimeric protein (MBP-1 fused to GAL4 DNA binding domain).
  • Assay of repressor activity on the herpes simplex virus thymidine kinase promoter.
  • Structure-function analysis using mutant MBP-1 proteins.
  • Site-directed mutagenesis to investigate the role of specific motifs (LXVXL).

Main Results:

  • The chimeric MBP-1/GAL4 protein exhibited transcriptional repressor activity.
  • MBP-1 possesses distinct N-terminal and C-terminal repressor domains and a middle activation domain.
  • The N-terminal repressor domain showed stronger activity than the C-terminal domain.
  • An LXVXL motif within both repressor domains was identified as critical for repression.
  • Mutations in the LXVXL motif abolished both transcriptional repression and cell growth suppression.

Conclusions:

  • MBP-1 functions as a complex transcriptional regulator with multiple regulatory domains.
  • The N-terminal and C-terminal repressor domains, particularly the LXVXL motif, are essential for MBP-1's function in regulating cell growth.
  • MBP-1 plays a significant role in the control of cell proliferation and tumor suppression.

More Related Videos

Promoter Capture Hi-C: High-resolution, Genome-wide Profiling of Promoter Interactions10:16

Promoter Capture Hi-C: High-resolution, Genome-wide Profiling of Promoter Interactions

Published on: June 28, 2018

Repressing Gene Transcription by Redirecting Cellular Machinery with Chemical Epigenetic Modifiers10:28

Repressing Gene Transcription by Redirecting Cellular Machinery with Chemical Epigenetic Modifiers

Published on: September 20, 2018

Related Concept Videos

RNA Polymerase II Accessory Proteins02:36

RNA Polymerase II Accessory Proteins

Proteins that regulate transcription can do so either via direct contact with RNA Polymerase or through indirect interactions facilitated by adaptors, mediators, histone-modifying proteins, and nucleosome remodelers. Direct interactions to activate transcription is seen in bacteria as well as in some eukaryotic genes. In these cases, upstream activation sequences are adjacent to the promoters, and the activator proteins interact directly with the transcriptional machinery. For example, in...
Co-activators and Co-repressors02:04

Co-activators and Co-repressors

Gene transcription is regulated by the synergistic action of several proteins that form a complex at a gene regulatory site. This is observed in eukaryotes, where the regulation of gene expression is a complex process. Regulatory proteins in eukaryotes can broadly be classified into two types – regulators that bind directly to specific DNA sequences and co-regulators that associate with regulatory proteins but cannot directly bind to the DNA. These co-regulators are further divided into...
Eukaryotic Transcription Inhibitors01:52

Eukaryotic Transcription Inhibitors

Certain biochemical processes, such as embryonic development and cell growth regulation, depend on the repression of specific genes. DNA binding proteins known as eukaryotic transcription inhibitors regulate the repression of gene expression in eukaryotes. The presence of these inhibitors at the required location and time in the cell is triggered by the presence of hormones and additional signals from other cells.
Eukaryotic transcription inhibitors usually contain two distinct domains, a DNA...
Master Transcription Regulators02:23

Master Transcription Regulators

Master transcription regulators are regulatory proteins that are predominantly responsible for regulating the expression of multiple genes. Often these genes work in concert to drive a  complex process. Activation of a master transcription regulator can lead to a cascade of transcriptional activation necessary for that outcome. These regulators can directly bind to the regulatory sequences of the various genes involved, or they can indirectly regulate transcription by binding to regulatory...
Abnormal Proliferation02:23

Abnormal Proliferation

Under normal conditions, most adult cells remain in a non-proliferative state unless stimulated by internal or external factors to replace lost cells. Abnormal cell proliferation is a condition in which the cell's growth exceeds and is uncoordinated with normal cells. In such situations, cell division persists in the same excessive manner even after cessation of the stimuli, leading to persistent tumors. The tumor arises from the damaged cells that replicate to pass the damage to the daughter...
Co-activators and Co-repressors02:04

Co-activators and Co-repressors

Gene transcription is regulated by the synergistic action of several proteins that form a complex at a gene regulatory site. This is observed in eukaryotes, where the regulation of gene expression is a complex process. Regulatory proteins in eukaryotes can broadly be classified into two types – regulators that bind directly to specific DNA sequences and co-regulators that associate with regulatory proteins but cannot directly bind to the DNA. These co-regulators are further divided into...