The polyadenylation signal is located in an intron. The BB represents an extra nucleolus. The BB is observed in male mammals. The BB is also observed in primordial germ cells. The BB is an example for gene inactivation by a change in chromosome conformation.
Most steroid hormones bind to receptors in the cell plasma membrane.
Steroid hormone receptors are transcription factors. Ecdysone is a steroid hormone. Synergistic Mechanisms A. State the general principle of synergistic mechanisms. B. Describe two examples that illustrate the principle. Convergent Extension A. Define the morphogenetic movement called convergent extension.