25 Questions
What is the approximate increase in transcription initiation stimulated by activation domains?
Hundredfold
What is the typical characteristic of the promoter region of a gene?
Absence of a readily classifiable mother TATA box
What is the role of activation domains in gene expression?
Stimulating transcription initiation
What is the relationship between the TATA box and the gene promoter region?
The TATA box is a part of the gene promoter region
What is the effect of the absence of a readily classifiable mother TATA box on gene expression?
It inhibits transcription initiation
What is the common feature of the amino terminal helices in the binding of DNA?
They form a specific structure to bind to the DNA major groove
Which of the following motifs is NOT involved in the dimerization of the DNA-binding protein?
Coiled coil
What is the primary function of the zinc finger motif in DNA-binding proteins?
To recognize specific DNA sequences
What is the characteristic of the leucine zipper motif in DNA-binding proteins?
It is composed of two symmetric alpha helices
What is the primary function of the helix-turn-helix motif in DNA-binding proteins?
To recognize specific DNA sequences
Where does a polypeptide hormone bind to its receptor?
In the target cell's plasma membrane
What is the direct result of a steroid hormone binding to its receptor?
Alteration of gene transcription
What is the primary function of a hormone-producing cell?
To produce a polypeptide hormone
What occurs when a polypeptide hormone binds to its receptor in a target cell?
A signal transduction pathway is activated
What is the key difference between polypeptide and steroid hormones in terms of their mechanism of action?
The location of their receptor binding
What is the function of the protein encoded by the RAP1 gene?
To bind to telomere repeat sequences
What is the name of the gene that codes for the protein Rap1p?
RAP1
What is the primary function of Rap1p in relation to telomeres?
To maintain telomere length
What is the region of the DNA that Rap1p binds to?
Telomere repeat sequences
What is the role of Rap1p in telomere maintenance?
To prevent telomere shortening
What is the primary mechanism of regulation of galactose utilization in yeast?
Regulation by a single Gal4p dimer binding to the UAS
What is the significance of the GAL1 and GAL10 genes in yeast?
They are involved in the regulation of galactose utilization
Why is the GAL system an ideal model for studying gene regulation?
Because it is a well-studied system that has revealed many principles of gene regulation
What is the role of the UAS in the regulation of galactose utilization in yeast?
It is a binding site for transcriptional activators of galactose utilization
What is the significance of the GAL locus in yeast?
It is a region of the genome that contains multiple genes involved in galactose utilization
Study Notes
Gene Regulation
- Transcription initiation can be stimulated up to a hundredfold by activation domains.
- Specific DNA-binding motifs include helix-turn-helix (HTH), zinc finger, and leucine zipper.
Hormone Signaling
- Hormone-producing cells release polypeptide hormones that bind to receptors embedded in the plasma membrane.
- The binding of a hormone to its receptor triggers a signal transduction pathway, leading to a cellular response.
- Steroid hormones bind to their receptors in the target cell plasma membrane, activating them.
Telomere Regulation
- Rap1p (product of the RAP1 gene) binds to telomere repeat sequences.
- This binding is important for regulating telomere function.
Regulation of Galactose Utilization in Yeast
- Gal4p dimer binds to upstream activation sequences (UAS) to regulate GAL1 and GAL10 gene expression.
- The GAL genes are not regulated by a UAS, but are instead controlled by other mechanisms.
- The regulation of galactose utilization in yeast is a well-studied system that illustrates several important principles of gene regulation.
Learn about the different amino terminal helices that bind to DNA, including helix-turn-helix, zinc finger, and leucine zipper motifs. Test your knowledge of these important protein structures and their functions.
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