The RAS gene encodes a signaling protein that hydrolyzes GTP to GDP. When bound by GDP, the RAS protein is inactive, whereas when bound by GTP, RAS protein activates a target protein, resulting in stimulation of cells to actively grow and divide. As shown in the accompanying sequence, a single base-pair mutation results in a mutant protein that is constitutively active, leading to continual promotion of cell proliferation. Such mutations play a role in the formation of cancer. You have cloned the wild-type version of the mouse RAS gene and wish to create a mutant form to study its biological activity in vitro and in transgenic mice. Outline how you would proceed.

Key Concepts

RAS Protein Function

The RAS protein is a critical signaling molecule that regulates cell growth and division. It functions as a molecular switch, toggling between an active form bound to GTP and an inactive form bound to GDP. When activated by GTP, RAS interacts with various downstream effectors to promote cellular proliferation. Understanding this mechanism is essential for studying mutations that lead to uncontrolled cell growth, such as those found in cancer.

Mutagenesis Techniques

Mutagenesis refers to the process of inducing mutations in a gene to study its function. Techniques such as site-directed mutagenesis allow researchers to create specific alterations in the DNA sequence of the RAS gene, resulting in a mutant protein. This approach is crucial for investigating how particular mutations affect protein activity and contribute to diseases like cancer, enabling the development of targeted therapies.

Transgenic Mouse Models

Transgenic mouse models are genetically modified organisms that carry foreign genes or mutations, allowing researchers to study gene function and disease mechanisms in a living system. By introducing a mutant form of the RAS gene into mice, scientists can observe the biological effects of the mutation in vivo, including its role in tumorigenesis. These models are invaluable for understanding the complexities of cancer biology and testing potential treatments.