Related Experiment Video

Updated: Aug 18, 2026

Analysis of Cell Cycle Position in Mammalian Cells
12:19

Analysis of Cell Cycle Position in Mammalian Cells

Published on: January 21, 2012

Disruption of RB/E2F-1 interaction by single point mutations in E2F-1 enhances S-phase entry and apoptosis

B Shan1, T Durfee, W H Lee

  • 1Center for Molecular Medicine/Institute of Biotechnology, University of Texas Health Science Center at San Antonio 78245, USA.

Proceedings of the National Academy of Sciences of the United States of America
|January 23, 1996
PubMed

Insights

The retinoblastoma protein (RB) regulates cell proliferation by binding to E2F transcription factors. Mutating key binding sites on E2F-1 disrupts this interaction, accelerating cell cycle progression and apoptosis.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Genetics

Background:

  • The retinoblastoma protein (RB) is a known negative regulator of cell proliferation.
  • RB functions by forming complexes with cellular proteins, notably the transcription factor E2F.
  • The precise biological consequences of the RB/E2F-1 interaction are under investigation.

Purpose of the Study:

  • To investigate the biological effects of disrupted RB/E2F-1 binding.
  • To identify critical residues within E2F-1 essential for RB interaction.

Main Methods:

  • Yeast two-hybrid system was employed to isolate E2F-1 point mutants unable to bind RB.
  • Sequence analysis was performed to pinpoint critical amino acid residues.
  • Expression of wild-type and mutated E2F-1 was compared for effects on cell cycle progression and apoptosis.

Main Results:

  • Five critical amino acid residues within the E2F-1 RB-binding domain were identified (Tyr411, Glu419, Asp-Leu-Phe423-425).
  • Mutations in these residues abolished RB binding but preserved E2F-1 transactivation potential.
  • Expression of RB-binding deficient E2F-1 mutants accelerated S phase entry and induced apoptosis compared to wild-type.

Conclusions:

  • Direct genetic evidence confirms the biological significance of the RB/E2F interaction.
  • The interplay between RB and E2F is crucial for regulating cell cycle progression.
  • Disruption of RB binding to E2F-1 leads to uncontrolled cell proliferation and cell death.

More Related Videos

Spatio-Temporal Manipulation of Small GTPase Activity at Subcellular Level and on Timescale of Seconds in Living Cells10:27

Spatio-Temporal Manipulation of Small GTPase Activity at Subcellular Level and on Timescale of Seconds in Living Cells

Published on: March 9, 2012

In Vivo Detection and Analysis of Rb Protein SUMOylation in Human Cells09:40

In Vivo Detection and Analysis of Rb Protein SUMOylation in Human Cells

Published on: November 2, 2017

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.
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...
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...
The Ras Gene02:38

The Ras Gene

The Ras-gene-encoded proteins are regulators of signaling pathways controlling cell proliferation, differentiation, or cell survival. The Ras-gene family in humans constitutes three primary members—the HRas, NRas, and KRas. These genes code for four functionally distinct yet closely related proteins—the HRas, NRas, KRas4A, and KRas4B. The involvement of mutant Ras genes in human cancer was first discovered in 1982 and is among the most common causes of human tumorigenesis.
Ras is a superfamily...
The Retinoblastoma Gene01:20

The Retinoblastoma Gene

Tumor suppressor genes are normal genes that can slow down cell division, repair DNA mistakes, or program the cells for apoptosis in case of irreparable damage. Hence, they play an essential role in preventing the proliferation of damaged cells.
The first-ever tumor suppressor gene called Rb was identified in retinoblastoma - a rare eye tumor in children. In inherited forms of the disease, a child inherits one defective copy of the Rb gene, which predisposes them to retinoblastoma. However,...
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...