Gal4 is a transcription factor that activates transcription of galactose metabolism genes in yeast. These genes are ‘turned on’ when yeast cells need to metabolize galactose. To identify promoter sequences necessary for regulation of transcription of GAL1, reporter gene fusions were made and introduced into yeast cells. Deletions of GAL1 promoter were cloned upstream of LacZ gene. β-Galactosidase activity was measured in presence of galactose.Shown below is a representation of the results obtained.In the diagrams below (not to scale!):• Construct 1 contains ~ 130bp of the promoter, which is predicted to have all the predicted/putative proximal promoter elements (indicated by the solid boxes) needed to regulate transcription of GAL1.• The stippled box is the core promoter.• The arrow represents the transcriptional start site for the reporter gene Lac Z• Number of + signs represents level of transcription• Star represents a mutation in DNA sequence at that location (few nucleotides are changed).3) How does one know that actual DNA sequence is important and not just position on the promoter? Do these experiments answer the question if location of GAL responsive regulatory sequences matters? The image displays a series of constructs labeled 1 to 5, showing different configurations of DNA fragments linked to the Lac Z gene. Each construct consists of segments marked with negative numbers (-130, -90, -70) representing their positions relative to a reference point, and are linked via arrows to the Lac Z gene. The blue boxes represent specific DNA sequences, and constructs 4 and 5 have an asterisk marking a particular site on the -130 segment.- **Construct 1**: Includes segments -130, -90, and -70 connected to the Lac Z gene. Shows high β-galactosidase activity (+++++).- **Construct 2**: Includes segments -90 and -70. Linked to the Lac Z gene. Displays moderate β-galactosidase activity (++). - **Construct 3**: Lacks any segment (-130, -90, -70) and serves as a baseline (Basal) with low β-galactosidase activity.- **Construct 4**: Similar to Construct 1, but contains an asterisk on the -130 segment. Shows moderate β-galactosidase activity (++).- **Construct 5**: Matches Construct 1 but with an asterisk on the -130 segment, displaying high β-galactosidase activity (+++++).The **B-Gal Activity** section on the right summarizes the β-galactosidase activity associated with each construct. Overall, this diagram elucidates the influence of different DNA segments on gene expression, measured by the activity of β-galactosidase.

Glycolysis is a primary source of energy in yeast, and glucose is by far the most favored carbon…

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Human Anatomy & Physiology (11th Edition)

11th Edition

ISBN:9780134580999

Author:Elaine N. Marieb, Katja N. Hoehn

Publisher:Elaine N. Marieb, Katja N. Hoehn

Chapter1: The Human Body: An Orientation

Section: Chapter Questions

Problem 1RQ: The correct sequence of levels forming the structural hierarchy is A. (a) organ, organ system,...

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Gal4 is a transcription factor that activates transcription of galactose metabolism genes in yeast. These genes are ‘turned on’ when yeast cells need to metabolize galactose. To identify promoter sequences necessary for regulation of transcription of GAL1, reporter gene fusions were made and introduced into yeast cells. Deletions of GAL1 promoter were cloned upstream of LacZ gene. β-Galactosidase activity was measured in presence of galactose.

Shown below is a representation of the results obtained.

In the diagrams below (not to scale!):

• Construct 1 contains ~ 130bp of the promoter, which is predicted to have all the predicted/putative proximal promoter elements (indicated by the solid boxes) needed to regulate transcription of GAL1.
• The stippled box is the core promoter.
• The arrow represents the transcriptional start site for the reporter gene Lac Z
• Number of + signs represents level of transcription
• Star represents a mutation in DNA sequence at that location (few nucleotides are changed).

3) How does one know that actual DNA sequence is important and not just position on the promoter? Do these experiments answer the question if location of GAL responsive regulatory sequences matters?