You are studying regulation of the yeast enzyme glutamine synthetase (GS), which is encoded by the GLN1 gene. You have isolated two mutants, designated gln2– and gln3–, that give decreased GS activity. Mating of either gln2– or gln3– haploids to wild type produces heterozygous diploids that show normal amounts of GS expression. When you cross either a gln2– or gln3– haploid to a gln1– strain the resulting diploids show normal expression of GS. 

Next, you decide to evaluate the promoter for the GLN1 gene. To do this you first fuse the promoter region to the LacZ coding sequence and then place this hybrid gene on an appropriate yeast plasmid. You find that cells carrying the hybrid gene express activity under the same conditions that GS is expressed in wild type cells, meaning that the promoter region you have selected contains all of the necessary cis-acting sequences for normal regulation. The figure below shows the effect of different 50 bp deletions in the promoter region on the amount of ß-galactosidase activity expressed by the reporter gene. how would you expect a gln2– gln3– double mutant to behave?

#Question id: 4679

#Unit 3. Fundamental Processes

Activated RecA stimulates autocleavage of

#Question id: 4680

#Unit 3. Fundamental Processes

A protein is a transcriptional activator,  which binds to a site upstream of a promoter called PRE and stimulates transcription of the cI (repressor) gene. This activator protein is

#Question id: 4681

#Unit 3. Fundamental Processes

The promoters whose activities are controlled by products of the genes transcribed from PR and PL

#Question id: 4682

#Unit 3. Fundamental Processes

what will happen, when repressor bound at OR1 and OR2,

#Question id: 4683

#Unit 3. Fundamental Processes

A very unstable protein in E. coli; it is degraded by a specific protease called FtsH (HflB), encoded by the hfl gene.

#Question id: 4684

#Unit 3. Fundamental Processes

The depicted region contains two genes (cI and cro) and three promoters (PR, PL, and PRM), these promoters are direct the transcription such as;

a) PR and PL are is a weak promoter and only directs efficient transcription when an activator is bound just upstream

b) PR and PL are strong, constitutive promoters, they bind RNA polymerase efficiently and direct transcription without     help from an activator

c) PRM, is a weak promoter and only directs efficient transcription when an activator is bound just upstream

d) PRM are strong, constitutive promoters, they bind RNA polymerase efficiently and direct transcription without help from an activator

Which of the following from the above combination is correct ?