Final answer:
A mutation in a structural gene's TATA box can prevent the binding of RNA polymerase, leading to a decrease or loss of gene expression.
Step-by-step explanation:
A mutation in a structural gene's TATA box can have consequences on the initiation of transcription. The TATA box is a sequence of DNA that helps to recruit RNA polymerase, the enzyme responsible for transcribing the gene. If the TATA box is mutated, it can prevent the binding of RNA polymerase, leading to a decrease or complete loss of gene expression.
For example, if the TATA box is mutated in such a way that it disrupts the binding of transcription factors or RNA polymerase, the gene may not be transcribed and translated into a functional protein. This can have various effects depending on the gene in question and its role in cellular processes.
Overall, the consequence of a mutation in a structural gene's TATA box can be a decrease or loss of gene expression, resulting in the disruption of normal cellular processes.