Explain how the following mutations would affect the transcr

Explain how the following mutations would affect the transcription of the yeast GAL1 gene:

a) A deletion within the GAL4 gene that removes the N-terminal DNA binding domain of Gal4p.

Solution

GAL OPERON CONTAINS MANY GENES LIKE

GAL 1,2,7,10 which are required to convert galactose to glucose-1-phosphate in euaryotes

We want these genes to express only when galactose is present ( LIKE IN PROKARYOTIC LAC OPERON) .... GAL4P is a transcripton factor which binds to enhnacer elements since it is a dimer and a transcription factor ( contains DNA binding domain and ACTIVATOR domain ), on deleting the DNA binding domain of GAL4P. It no longer binds to DNA resulting in no enhacer activation effect by GAL4P in presence of galactose, hence operon would stop transcription at higher levels and thus GAL operon would be shut off, and galactose signalling wont work anymore

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