16. Regulation of Expression

In a eukaryote, transcription factors called activators may stimulate gene expression by binding to DNA sites called __________.

Enhancers __________.

Dioxin, produced as a by-product of various industrial chemical processes, is suspected of causing cancer and birth defects in animals and humans. It apparently acts by entering cells and binding to specific proteins, which then enter the nucleus and alter the pattern of gene expression. Therefore, dioxin acts by mimicking the action of __________.

A high rate of gene transcription in eukaryotic cells is usually dependent on __________.

MyoD promotes muscle cell development by __________.

Which of these statements about enhancers is correct? a. They contain a unique base sequence called a TATA box. b. They are located only in 5′ untranslated regions. c. They are located only in introns. d. They are found both upstream and downstream from the transcription start site and are functional in any orientation.

Which of these statements about enhancers is correct? a. They contain a unique base sequence called a TATA box. b. They are located only in 5′ untranslated regions. c. They are located only in introns. d. They are found both upstream and downstream from the transcription start site and are functional in any orientation.

The functioning of enhancers is an example of a. a eukaryotic equivalent of prokaryotic promoter functioning. b. transcriptional control of gene expression. c. the stimulation of translation by initiation factors. d. post-translational control that activates certain proteins.

In eukaryotes, what allows only certain genes to be expressed in different types of cells?

In eukaryotes, what allows only certain genes to be expressed in different types of cells?

Compare and contrast the items in each pair: (c) general transcription factors and sigma.

Compare and contrast the items in each pair: (a) enhancers and the E. coli CAP binding site

Compare and contrast the items in each pair: (b) promoter-proximal elements and the operator of the lac operon

Compare and contrast the items in each pair: (c) general transcription factors and sigma.

Compare and contrast the items in each pair: (a) enhancers and the E. coli CAP binding site

Compare and contrast the items in each pair: (b) promoter-proximal elements and the operator of the lac operon

In the follow-up work to the experiment shown in Figure 19.6, the researchers used a technique that allowed them to see if two DNA sequences are in close physical proximity (association). They applied this method to examine how often an enhancer and the core promoter of the Hnf4a regulatory gene were near each other. A logical prediction is that compared with rats born to mothers fed a healthy diet, the Hnf4a gene in rats born to mothers fed a protein-poor diet would a. show no difference in how often the promoter and enhancer associated. b. never show any promoter–enhancer association. c. show a lower frequency of promoter–enhancer association. d. show a higher frequency of promoter–enhancer association.

The Hawaiian bobtail squid (Euprymna scolopes) is able to glow from luminescent Vibrio fischeri bacteria held in its light organs. As it swims at night near the ocean surface, it adjusts the amount of light visible to predators below to match the light from the stars and moon. Predators have difficulty seeing the illuminated squid against the night sky. The bacteria glow in response to a molecule that regulates expression of genes involved in light-producing chemical reactions. The regulator controls production of the genes' mRNA. Therefore, the light-producing genes are under a. transcriptional control. b. translational control. c. post-translational control. d. negative control.

The Hawaiian bobtail squid (Euprymna scolopes) is able to glow from luminescent Vibrio fischeri bacteria held in its light organs. As it swims at night near the ocean surface, it adjusts the amount of light visible to predators below to match the light from the stars and moon. Predators have difficulty seeing the illuminated squid against the night sky. The bacteria glow in response to a molecule that regulates expression of genes involved in light-producing chemical reactions. The regulator controls production of the genes' mRNA. Therefore, the light-producing genes are under a. transcriptional control. b. translational control. c. post-translational control. d. negative control.

The light-producing genes of V. fischeri are organized in an operon that is under positive control by an activator protein called LuxR. Would you expect the genes of this operon to be transcribed when LuxR is bound or not bound to a DNA regulatory sequence? Explain.

The light-producing genes of V. fischeri are organized in an operon that is under positive control by an activator protein called LuxR. Would you expect the genes of this operon to be transcribed when LuxR is bound or not bound to a DNA regulatory sequence? Explain.