Related Experiment Videos
The retinoblastoma gene: role in cell cycle control and cell differentiation
1Department of Tumor Biology, Karolinska Institute, Stockholm, Sweden.
Abstract:
The retinoblastoma (RB) gene is the prototype tumor suppressor gene. It encodes a nuclear protein that acts as a cell cycle control checkpoint at the G1 phase. Deletion or inactivation of both RB alleles plays an essential, rate-limiting role in retinoblastoma and in the osteosarcomas that arise within families that carry a mutated RB gene. RB inactivation is also found in other sarcomas, small cell carcinoma of the lung, and in carcinoma of the breast, bladder, and prostate. Transforming proteins encoded by SV40, and the transforming or tumor-associated subtypes of adenoviruses and human papilloma viruses (HPV) can bind RB, thereby blocking its normal function. The EBNA-5 protein of Epstein-Barr virus (EBV) is also able to bind RB in vitro. In addition, RB can interact with several cellular proteins, including the transcription factor E2F. RB gene knock-out mice die in utero around day 14 of gestation. The embryos show disturbed neural and hematopoietic differentiation, indicating that RB is vitally important for these processes. This notion is further supported by studies demonstrating that RB expression in mouse embryo tissues is highest in cells undergoing differentiation, and that RB is required for MyoD-induced muscle differentiation.
Insights
The retinoblastoma (RB) gene is a key tumor suppressor controlling cell division. Its inactivation is crucial in various cancers, highlighting its vital role in preventing tumor formation.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- The retinoblastoma (RB) gene functions as a critical tumor suppressor.
- RB protein regulates the G1 phase cell cycle checkpoint.
- RB gene inactivation is implicated in retinoblastoma and other cancers.
Purpose of the Study:
- To elucidate the role of the RB gene in cell cycle control and tumor suppression.
- To investigate the interaction of RB with viral and cellular proteins.
- To understand the developmental importance of RB.
Main Methods:
- Analysis of RB gene function in cancer.
- Studies on viral protein interactions with RB.
- Examination of RB gene knock-out mouse models.
- Investigation of RB expression during differentiation.
Main Results:
- RB inactivation is essential for retinoblastoma and associated osteosarcomas.
- RB is involved in other cancers including lung, breast, bladder, and prostate.
- Viral proteins (SV40, adenovirus, HPV, EBV) and cellular proteins (E2F) interact with RB.
- RB gene knock-out mice exhibit developmental defects, underscoring its importance in differentiation.
Conclusions:
- The RB gene is a fundamental tumor suppressor crucial for cell cycle regulation.
- RB's interaction with viral oncoproteins and cellular factors impacts its function.
- RB plays a vital role in embryonic development and cellular differentiation.