Which mutation results in an altered gene product that acts antagonistically to the normal gene product?

Which mutation results in an altered gene product that acts antagonistically to the normal gene product?

• A. Gain-of-function mutation
• B. Dominant-negative mutation
• C. Loss-of-function mutation
• D. Point mutation

Answer: (B)

A dominant-negative mutation is characterized by a change in the gene product that not only loses normal function but also actively interferes with the function of the wild-type gene product. This type of mutation typically occurs in multimeric proteins, where the altered protein can still form complexes with normal proteins but disrupts their functionality. For example, if a mutation leads to a protein being unable to perform its usual role and, in addition, this mutated protein binds to other subunits to prevent them from functioning correctly, it creates an antagonistic effect against the wild-type protein. In contrast, a gain-of-function mutation refers to a change in the gene product that enhances its activity or leads to new functions, which does not inherently involve antagonism toward the normal protein. A loss-of-function mutation usually results in the complete or partial inactivation of the gene product, but it may not have a direct antagonistic effect on the wild-type protein unless it affects a multimeric structure in a specific way. A point mutation, depending on its specific effect, can lead to various outcomes, including loss, gain, or no change in function, but does not specifically indicate antagonism toward normal function. Thus, the dominant-negative mutation clearly fits the definition as it encompasses the idea

A dominant-negative mutation is characterized by a change in the gene product that not only loses normal function but also actively interferes with the function of the wild-type gene product. This type of mutation typically occurs in multimeric proteins, where the altered protein can still form complexes with normal proteins but disrupts their functionality. For example, if a mutation leads to a protein being unable to perform its usual role and, in addition, this mutated protein binds to other subunits to prevent them from functioning correctly, it creates an antagonistic effect against the wild-type protein.

In contrast, a gain-of-function mutation refers to a change in the gene product that enhances its activity or leads to new functions, which does not inherently involve antagonism toward the normal protein. A loss-of-function mutation usually results in the complete or partial inactivation of the gene product, but it may not have a direct antagonistic effect on the wild-type protein unless it affects a multimeric structure in a specific way. A point mutation, depending on its specific effect, can lead to various outcomes, including loss, gain, or no change in function, but does not specifically indicate antagonism toward normal function.

Thus, the dominant-negative mutation clearly fits the definition as it encompasses the idea