Chapter 18, Problem 4P

In mice, a group of so-called Hox genes encode transcription factors that control the patterning of the animal’s vertebral column. For example, the cervical vertebrae (labeled C1 and C2 below) express both HoxA1 and HoxD4 proteins, while the occipital bones at the base of the animal’s skull (labeled E below) express HoxA1 only.

 

Scientists hypothesized that the expression of HoxD4, controlled at the level of transcription initiation, is what makes C1 and C2 develop differently from the occipital bones.

a.	Describe a gene construct you could introduce by pronuclear injection that you could use to test this hypothesis.
b.	If the hypothesis is correct, what result would you expect in the transgenic mice?