Related Experiment Video
Updated: Aug 9, 2026
Preparation of Cell-lines for Conditional Knockdown of Gene Expression and Measurement of the Knockdown Effects on E4orf4-Induced Cell Death
Published on: October 21, 2012
Adenovirus E1a as a tumor-suppressor gene
1Institute for Molecular Virology, St Louis University Medical Center, Missouri 63110.
Abstract:
The E1a gene of group C adenoviruses is one of the most studied transforming genes of DNA tumor viruses. These transforming genes have been conventionally considered as dominant oncogenes since they transform cells in vitro and many of the resulting transformed cell lines induce tumors in experimental animals. It now appears that, in addition to its well-known transforming activities, E1a possesses activities which suppress transformation, tumorigenesis and malignant progression (metastasis) of tumor cells. Thus, E1a appears to meet the definition of both a dominant oncogene and a tumor-suppressor gene.
Insights
The adenovirus E1a gene acts as both an oncogene, promoting cell transformation, and a tumor suppressor, inhibiting cancer progression and metastasis. This dual role challenges traditional cancer gene classifications.
Area of Science:
- * Molecular biology
- * Oncology
- * Virology
Background:
- * The E1a gene from group C adenoviruses is a well-researched transforming gene in DNA tumor viruses.
- * Transforming genes are typically considered dominant oncogenes, inducing cell transformation and tumor formation.
- * Conventional understanding views these genes solely as drivers of cancer development.
Purpose of the Study:
- * To investigate the multifaceted roles of the adenovirus E1a gene beyond its known transforming activities.
- * To explore whether E1a exhibits tumor-suppressive functions.
- * To reconcile the dual nature of E1a as both an oncogene and a tumor-suppressor gene.
Main Methods:
- * Analysis of E1a gene function in cell transformation assays.
- * Evaluation of E1a's impact on tumorigenesis in experimental models.
- * Assessment of E1a's influence on the malignant progression of tumor cells, including metastasis.
Main Results:
- * The E1a gene demonstrates transforming capabilities, consistent with its oncogenic nature.
- * E1a also exhibits significant activities that suppress transformation, tumorigenesis, and metastasis.
- * These findings indicate a dual role for E1a in cancer development.
Conclusions:
- * The adenovirus E1a gene possesses both oncogenic and tumor-suppressive properties.
- * E1a challenges the conventional classification of genes as solely oncogenes or tumor suppressors.
- * E1a functions as both a dominant oncogene and a tumor-suppressor gene, highlighting the complexity of viral oncogenesis.
Related Concept Videos
01:12Loss of Tumor Suppressor Gene Functions
When the tumor suppressor genes develop mutations or are lost, cells start growing out of control, leading to cancer. However, a single functional copy of the tumor suppressor gene is enough for the cells to maintain their normal functions and cell...
01:05Cancer-Critical Genes II: Tumor Suppressor Genes
When the function of certain critical genes, especially those involved in cell cycle regulation and cell growth signaling cascades, gets disrupted, it upsets the cell cycle progression. Such cells with unchecked cell cycles start proliferating uncontrollably and eventually develop into tumors.
Such genes that act...
01:20The Retinoblastoma Gene
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,...
01:05Cancer-Critical Genes II: Tumor Suppressor Genes
When the function of certain critical genes, especially those involved in cell cycle regulation and cell growth signaling cascades, gets disrupted, it upsets the cell cycle progression. Such cells with unchecked cell cycles start proliferating uncontrollably and eventually develop into tumors.
Such genes that act...
01:12Loss of Tumor Suppressor Gene Functions
When the tumor suppressor genes develop mutations or are lost, cells start growing out of control, leading to cancer. However, a single functional copy of the tumor suppressor gene is enough for the cells to maintain their normal functions and cell...
01:20The Retinoblastoma Gene
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,...