5. Homeobox-containing genes (Hox genes) play important roles in animal embryonic development by regulating the expression of many other genes that influence morphology. Which of the following statements about Hox genes is NOT correct? (A) The Hox proteins contain a helix-turn-helix structure that is responsible for DNA binding. (B) The subcellular localization of Hox proteins is primarily on the cell membrane. (C) Gain-of-function of Hox genes often results in developmental defects. (D) Loss-of-function of Hox genes often results in developmental defects. (E) Hox genes regulate the development of the anterior-posterior axis in most animals.