Yeast genes have cis-acting elements upstream of their promoters, similar to enhancers, called upstream activating sequences or UAS Several target genes involved in galactose utilization are regulated by onc UAS that has four binding sites for the protein Gal4. The GAL genes are regulated by Gal4, Gal80 and Gal3 in responsc to galactose. These genes are also regulated by glucose (the preferred carbon source). Predict the expression of the GAL genes in the following mutants or conditions: use ON to indicate transcription occurs or OFF to imdicate no transcription. Expression of GAL genes No glucose and no galactose With galactose and no glucose Strain With glucose Wild-type gal4 mutant gal80 mutant gal3 mutant migl mutant > B of 11 1567 words HFocus B Ix Paragraph Styles Dictate Sensitivit As a graduate student, Prof. Rolfes studied the E. coli regulatory protein PurR. 6. PurR regulates several small operons and single genes whose encoded proteins are involved in the biosynthesis of the purine nucleotides A and G. PurR binds to an operator (0) in the RURGMN operon to regulate its transcription. purG is a structural gene that encodes an enzyme, glutamine PRPP amidotransferase (GPAT), and its enzyme activity can be measured. The expression of purG is repressed when cells are grown in media with guanine, and that repression requires PurR (see first two lines in the table below). Predict the GPAT activity in the following strains. R refers to pwrR: O to purQ; G to purG; the + means functional and the- means non-functional. a. GPAT activity Strain Genotype R+ Q+ G+ Growth with guanine Low activity High activity Growth without guanine High activity High activity R-O+ G+ R+ O+G R+ 0-G+ R-0+ G+/F R+ R+ 0-G+/F' O+ G+ No activity No activity R+ 0- G-/F 0+ G+ b. PurR is 26% identical to LacI, thus the proteins are homologous. Both proteins bind to DNA at operators and both proteins interact with small molecules that regulate their activity: Lacl binds allo-lactose and PurR binds guanine, Compare and contrast the role(s) for the small molecules that affect Lacl and PurR. Answer: D Focus f 11 1540 words Aa Book Pro