THE RETINOBLASTOMA GENE IS A TUMOUR SUPPRESSOR GENE. WHAT CELLULAR PATHWAY IS THE RETINOBLASTOMA PROTEIN INVOLVED IN

• A. Apoptosis
• B. Controlling the cell cycle ✓
• C. Angiogenesis
• D. Immunity

The retinoblastoma gene, also known as the RB1 gene, is a tumor suppressor gene that plays a crucial role in controlling the cell cycle. The retinoblastoma protein (pRB), encoded by the RB1 gene, regulates the progression of the cell cycle from the G1 phase to the S phase. By interacting with various transcription factors and other regulatory proteins, pRB helps to prevent uncontrolled cell proliferation and tumorigenesis.

The retinoblastoma protein is primarily involved in regulating the transition from G1 phase to S phase of the cell cycle. In normal cells, pRB acts as a checkpoint that inhibits cell cycle progression until conditions are favorable for DNA replication. When pRB is phosphorylated by cyclin-dependent kinases (CDKs) in response to growth signals, it releases its inhibitory effect on E2F transcription factors, allowing them to activate genes required for DNA synthesis and cell division. Dysregulation of the retinoblastoma pathway can lead to uncontrolled cell proliferation and cancer development.

In summary, the retinoblastoma protein is primarily involved in controlling the cell cycle by regulating the transition from G1 phase to S phase and preventing aberrant cell division.

In other words, the retinoblastoma protein is involved in controlling the cell cycle. It functions as a cell cycle regulator, specifically governing the G1 to S phase transition. The retinoblastoma protein (pRb) plays a crucial role in regulating cell proliferation by tightly controlling the cell cycle checkpoint at the G1/S phase boundary. It primarily acts by modulating the activities of the E2F transcription factor family members through direct binding or recruiting co-repressors. In normal eukaryotic cells, pRb helps maintain proper cell division and prevents uncontrolled cell proliferation, thus functioning as a tumor suppressor gene.