Related Experiment Video

Updated: Oct 12, 2026

Immunostaining for DNA Modifications: Computational Analysis of Confocal Images
09:42

Immunostaining for DNA Modifications: Computational Analysis of Confocal Images

Published on: September 7, 2017

Methylation-sensitive protein-DNA interaction at the cell cycle regulatory domain of human thymidine kinase promoter

Z F Chang1, S M Cheng

  • 1Department of Biochemistry, Chang Gung Medical College, Tao-Yuan, Taiwan, R.O.C.

Biochemical and Biophysical Research Communications
|November 30, 1992
PubMed

Insights

This study reveals that DNA methylation influences thymidine kinase (TK) gene transcription by affecting DNA-protein complex formation in human tumor cells. This mechanism may play a role in cell cycle regulation.

Area of Science:

  • Molecular Biology
  • Epigenetics
  • Cancer Research

Background:

  • The human thymidine kinase (TK) gene is crucial for DNA synthesis and cell cycle progression.
  • Regulation of TK gene expression involves complex interactions between DNA sequences and nuclear proteins.

Purpose of the Study:

  • To investigate DNA-protein complex formation within the cell-cycle regulatory unit (CCRU) of the human TK promoter.
  • To determine the role of the CCAAT box and DNA methylation in regulating TK gene transcription.

Main Methods:

  • Analysis of DNA-protein complex formation in nuclear extracts from human cell lines.
  • Site-directed mutagenesis to identify critical DNA elements (CCAAT box).
  • Assessment of TK mRNA expression under serum deprivation.
  • Investigation of DNA methylation effects using HhaI digestion.

Main Results:

  • A distinct DNA-protein complex was identified in human tumor cell lines, requiring the CCAAT box for formation.
  • Serum deprivation altered TK mRNA expression but not the DNA-protein complex in HeLa cells.
  • DNA methylation at the HhaI site significantly reduced nuclear protein binding activity.

Conclusions:

  • The CCAAT box is essential for DNA-protein complex formation in the TK promoter's CCRU.
  • DNA methylation of the TK promoter may regulate TK transcription during the late G1/S phase of the cell cycle.

More Related Videos

An Engineered Split-TET2 Enzyme for Chemical-inducible DNA Hydroxymethylation and Epigenetic Remodeling08:34

An Engineered Split-TET2 Enzyme for Chemical-inducible DNA Hydroxymethylation and Epigenetic Remodeling

Published on: December 18, 2017

Continuous Fluorescence-Based Endonuclease-Coupled DNA Methylation Assay to Screen for DNA Methyltransferase Inhibitors06:07

Continuous Fluorescence-Based Endonuclease-Coupled DNA Methylation Assay to Screen for DNA Methyltransferase Inhibitors

Published on: August 5, 2022

Related Concept Videos

Negative Regulator Molecules01:23

Negative Regulator Molecules

Positive regulators allow a cell to advance through cell cycle checkpoints. Negative regulators have an equally important role as they terminate a cell’s progression through the cell cycle—or pause it—until the cell meets specific criteria.
Epigenetic Regulation01:46

Epigenetic Regulation

Epigenetic mechanisms play an essential role in healthy development. Conversely, precisely regulated epigenetic mechanisms are disrupted in diseases like cancer.
DNA Damage can Stall the Cell Cycle02:36

DNA Damage can Stall the Cell Cycle

In response to DNA damage, cells can pause the cell cycle to assess and repair the breaks. However, the cell must check the DNA at certain critical stages during the cell cycle. If the cell cycle pauses before DNA replication, the cells will contain twice the amount of DNA. On the other hand, if cells arrest after DNA replication but before mitosis, they will contain four times the normal amount of DNA. With a host of specialized proteins at their disposal,cells must use the right protein at...
Positive Regulator Molecules02:39

Positive Regulator Molecules

Mitotic cell division results in daughter cells that exactly resemble the parent cell. However, errors in the DNA replication or distribution of genetic material may lead to genetic mutations that may be passed down to every new cell formed from the resulting abnormal cell. Propagation of such mutant cells is restricted through checkpoint mechanisms present at different stages of the cell cycle. These checkpoints involve regulator molecules that either promote or demote cell cycle events.
Inhibition of Cdk Activity02:34

Inhibition of Cdk Activity

The orderly progression of the cell cycle depends on the activation of Cdk protein by binding to its cyclin partner. However, the cell cycle must be restricted when undergoing abnormal changes. Most cancers correlate to the deregulated cell cycle, and since Cdks are a central component of the cell cycle, Cdk inhibitors are extensively studied to develop anticancer agents. For instance, cyclin D associates with several Cdks, such as Cdk 4/6, to form an active complex. The cyclin D-Cdk4/6 complex...
Epigenetic Regulation01:37

Epigenetic Regulation

Epigenetic changes alter the physical structure of the DNA without changing the genetic sequence and often regulate whether genes are turned on or off. This regulation ensures that each cell produces only proteins necessary for its function. For example, proteins that promote bone growth are not produced in muscle cells. Epigenetic mechanisms play an essential role in healthy development. Conversely, precisely regulated epigenetic mechanisms are disrupted in diseases like cancer.
X-chromosome...