Question

Nucleosome positioning along the DNA can influence where transcriptional regulatory proteins are able to bind DNA.

If a nucleosome is bound to an enhancer sequence, it may outcompete a regulatory protein from binding the same sequence.

Conversely, if an enhancer sequence is in the linker DNA where the nucleosome is absent, the regulatory protein does not have to compete with the nucleosome.

The position of the nucleosome can alter the accessibility of a sequence of DNA to DNA binding proteins.
Suppose that this region of DNA contained several enhancer sequences that bind highly conserved regulatory proteins to stimulate transcription of a gene in this region, and that binding is more efficient when the enhancer sequence isnot associated with a nucleosome. Use this information to complete these sentences.

Fill in the blanks with the appropriate words. Words may be used more than once.

a. Fall within linker DNA

b. fewer

c. be bound by nucleosomes

d. more

Since sea urchins have longer linker DNA segments than Drosophila melanogaster, when this region of DNA is moved to the sea urchin it is likely that these enhancer sequences will_______________.

With___________enhancer sequences available in sea urchins to bind regulatory proteins that stimulate transcription, the same region of DNA will likely generate__________RNA transcripts.

Answer 1

Since sea urchins have longer linker DNA segments than Drosophila melanogaster, when this region of DNA is moved to the sea urchin it is likely that these enhancer sequences will fall with linker DNA With more enhancer sequences available in sea urchins to bind regulatory proteins that stimulate transcription, the same region of DNA will likely generate more RNA transcripts.