Genetic engineering has been used to create a strain of mice that are unable to synthesize dopamine. These mice can survive embryonic development only if they are rescued by the provision of an external source of dopamine. Which of the following genes would be the most likely target for inactivation to produce such dopamine deficient mice?

Question

Quizplus · Accepted Answer

Tyrosine hydroxylase is the enzyme responsible for the conversion of tyrosine to L-DOPA, the precursor to dopamine. Inactivating this gene would prevent dopamine synthesis.  Tyrosine is the amino acid precursor for the synthesis of the catecholamines. The catecholamine neurotransmitters are dopamine, norepinephrine, and epinephrine. Tyrosine is transported into catecholamine-secreting neurons and adrenal medullary cells where catecholamine synthesis takes place. The first step in the process requires tyrosine hydroxylase. The hydroxylation reaction generates DOPA (3,4-dihydrophenylalanine); then DOPA decarboxylase converts DOPA to dopamine.

Genetic Engineering Has Been Used to Create a Strain of Mice