Q18.2-5CC. - Campbell Biology

Question

Suppose you compared the nucleotide sequences of the distal control elements in the enhancers of three genes that are expressed only in muscle cells. What would you expect to find? Why?

Step-by-Step Solution

Answer

The distal control elements of the three genes of the muscle cell must have similar sequences or identical motif.

 

The same specific transcription factors in muscle cells bind to the enhancers of all three genes to enhance transcription.

Step 1: Enhancers

An enhancer is a sequence in the DNA template that enhances the transcription of genes. It contains short DNA sequences, which are referred to as distal control elements. Enhancers are located either upstream or downstream of a gene.

Transcription factors bind to the enhancer region to increase transcription. Activators bind to the distal control elements and thus interact with mediator proteins and transcription factors to enhance transcription.

Step 2: Nucleotide sequence of the distal control elements of three genes

The nucleotide sequence of all the enhancers must be identical, or all the enhancers must share a motif to which the same specific transcription factor can bind to enhance the transcription process.

Step 3: The enhancers have an identical nucleotide sequence

Transcription factors play an essential role in activating the enhancer region of DNA. The same specific transcription factors bind to the enhancers of all the genes in muscle cells.

Thus, specific transcription factors will bind to the same motif of the enhancers of all the genes to enhance transcription.