Imagine that you are studying the control of β-globin gene expression in immature red blood cells (mature red blood cells contai
n β-globin protein but lack a nucleus and therefore the β-globin gene). If you deleted a sequence of DNA outside the protein-coding region of the β-globin gene and found that this increased the rate of transcription, the deleted sequence likely functions as a(n) _____.silencerenhancerpromoterpromoter-proximal elementany of the above
Silencers are the position and orientation free sequences that are present outside the protein-coding sequence of a gene. Silencers serve as a binding site for some transcriptional regulatory proteins that tend to inhibit gene expression. Binding of these "repressor" proteins to the silencers inhibits the gene expression.
The deletion of silencers from DNA would increase the rate of the gene expression as the inhibitory transcription regulatory proteins do not have binding sites to inhibit the gene expression. Therefore, the deletion of silencer sequences of the beta-globin gene would have caused the increased rate of its expression.
A, B, and C, are all observing the situations, while D states the deer walked down the path earlier because of the tracks, this is hardly obersavable, and you would have to infere the deer took the path early.
