Question

Eukaryotic transcription factors often bind to DNA at sites long distances from the transcription start site. These DNA regions are called:

Answer 1

The transcription of the eukaryote is different from those of prokaryotes in the following basis:

• The various structural genes which are required for various metabolic pathway are not located in the same chromosome, they are located in adjacent or different chromosomes.
• The structural gene hs both coding and non-coding sequence that is exons and introns.
• Each of the structural gene has its own promoter region has sensor genes which to sense any change occur in the environment of the cell that in growth and development in response to vitamins or hormones or chemicals or pathogen presence in its surface.
• It also has an integrase gene which is to integrate the information from various genes at various chromosomes for the metabolic pathway
• They also have silencer and enhancer, which is located at a far distance from the transcription unit. At this location the transcription factors bind in response to it enhancing or depressing transcription occurs.

Based on the binding of the transcription factors on the enhancer regions they either enhance or repress the transcription by:

• On RNA polymerase - either prevent the binding of the RNA polymerase to the DNA or stabilizing the binding of the RNA polymerase to the structural DNA.
• On coactivators and corepressors - In response to the transcription factors either coactivator produced to enhance the activity or produce corepressor to block the transcription.
• On histone acetylation - By producing two types of enzymes histone acetyltransferase and histone deacetylase. That is the enzyme histone acetyltransferase causes the binding between the histone and DNA weak so that the transcription is up-regulated, whereas in the case of histone deacetylase enzyme strengthen the bonding between the histone and DNA so that the transcription is down-regulated.

So the answer is DNA binding domain, it is the region of the DNA where the enhancer or promoter is located.

Other than DNA binding there are two more domain - activation domain, where the coactivator or corepressor bind to regulate transcription and the other is signal sensing domain, where the genes for detecting the external changes are located.