Insulators:
A. are boundary elements that function to prevent the enhancer for one gene from activating the promoter of another gene.
B. are DNA sequences that can prevent packaging of a gene into heterochromatin.
C. require the zinc-finger protein CTCF to function in higher eukaryotes.
D. All of the choices are correct.
The AP-1 transcription factor is a heterodimer of the Fos and Jun proteins. What is the protein-dimerization motif present in these two proteins?
A. basic leucine zipper
B. helix-turn-helix
C. zinc finger
D. homeodomain
Figure 2 depicts the region of cells (shaded gray) in which the even-skipped protein is present in a developing Drosophila embryo. Which of the following statements about the control of the eve gene is likely true based on Figure 2?
A. The Hunchback protein is an eve repressor.
B. The bicoid gene is an insulator for eve gene expression.
C. The Krppel protein is an eve repressor.
D. The Giant protein is an eve activator.
32P-end-labeled DNA fragment contains the AP-1binding site sequence.
The DNA was mixed with Fos, FosC (a fragment of Fos), or Jun (all of which would form a homodimer), or with a mixture of Fos and Jun or a mixture of FosC and Jun (both of which would form the two types of homodimer and the heterodimer). Reactions were analyzed by polyacrylamide gel electrophoresis, thenautoradiography. The results are shown in Figure 1.
This technique is called:
A. DNA footprinting.
B. electrophoretic mobility shift assay.
C. reporter gene assay.
D. immunoprecipitation.
The technique of deletion analysis revealed the modular architecture of Gal4p. In deletion analysis, nucleases or restrictionenzymes are used to selectively:
A. delete pieces of DNA froma specified gene.
B. remove truncated protein products of a gene.
C. restore in vitro activity of proteins to mutant cells.
D. activate genes in vivo using a reporter assay.
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