Question

TATA-Binding Protein (TBP) binds the TATA box during eukaryotic transcription initiation. TBP contains an internal signal sequence that helps guide the protein to its appropriate final location.

8b. You identify a budding yeast stain that has a mutation in the TBP gene sequence. The mutation removes the signal sequence of TBP protein. As a consequence of the signal sequence mutation, where will the protein end up? [3 pts]

Answer 1

Ans.) The TATA-binding protein, is required in initiation step of transcription process in which it helps in association of DNA pol III to the promoter region by identifying TATA box. However several other co-factors are also required for initiation process and its observed that transcription can begin without presence of TBP protein.

As, TBP is necessary in nucleus but as we known all proteins are translated in cytoplasm. But in this case as the protein is mutated and there is absence of signal sequence, so this protein will first will be enter endoplasmic reticulum and will undergo folding and post translational modifications and from ER it will enter golgi apparatus. Since, protein is mutated, so from golgi complex this mutated protein will be packed in vacuoles and will be sent to lysosomes where this mutated protein will be destroyed.