Explain how the following mutations would affect transcription of the yeast GAL1 gene in the presence of galactose.

A deletion of the entire GAL3 gene.

Video transcript

Hey everyone, Let's take a look at this question together. G A L three encodes a transcription regulator in the G A. L. Gene activation in the presence of galactose. The deletion of the entire G A L three gene leads to what, So let's recall what we've learned about the G A L three gene and what a deletion of the entire G A L three gene would lead to. So let's use the information we know about. If we had a deletion of the entire G A L three gene and take a look at the following answer. So starting off with answer choice A we see stable G A L A T to G A L three complex formation enhancing the G A. L. Gene expression. Now we know that if we have that deletion of the entire G L three gene, we'll end up with a non formation of GAL GAL three complex, which would mean that we don't have that enhancing of the G A. L. Gene expression. So answer choice A is incorrect. Answer choice B says G A L A T G a L three complex is not formed enhancing the G A. L. Gene expression. We know that because we have the deletion of the entire G A L three gene and we have that non formation that means that the enhancing of the G A. L. Gene expression is not allowed. And so answer choice B is also incorrect and then answer choice C says G A L a t g a L three complex is not formed, inhibiting the G L gene expression, which we know is a true statement because the g a l a t e g a L three complex is not formed, inhibiting the JL gene expression because it leads to the formation of the three A l GAL four complex, which this complex inhibits between expression. And so answer choice C is a true statement about what would happen if we deleted that entire GAL three gene. So answer choice C is the correct answer. I hope you found this video to be helpful. Thank you and goodbye.