Aresearcher has identified a mutation in mouse cells that results in these cells having abnormally low levels of pax3 (a gene involved in muscle development) gene transcription. he determines that this is a result of a mutation affecting a promoter-proximal element. this mutation:
a. occurs upstream of the pax3 promoter.
b. may occur in a ccaat box. may occur in a gc-rich box.
c. may affect the ability of regulatory proteins to associate with pax3
d. all of the answers are correct.