You are studying the characteristics of a particular protein isolated from cells of a squamous cell carcinoma and comparing it to the same protein isolated from nonaffected cells from the same tissue. When grown in culture, the normal cells arrest in the G₀ phase of the cell cycle. Analysis of the 2 proteins demostrates that the normal protein binds to DNA, whereas, the mutated protein from the carcinoma cells does not. These findings are most characteristic of which of the following?

Question

Quizplus · Accepted Answer

The normal protein binding to DNA and causing cell cycle arrest suggests it is a tumor suppressor gene protein, which typically regulates cell growth and division. The mutated version in carcinoma cells likely loses this function, contributing to uncontrolled cell proliferation.

You Are Studying the Characteristics of a Particular Protein Isolated