What type of interaction occurs between the β-propeller domain and the LDL-binding domain at low pH?

#Question id: 19160

#Unit 13. Methods in Biology

#Question id: 13197

#Unit 1. Molecules and their Interaction Relevant to Biology

#Question id: 18916

#Unit 13. Methods in Biology

#Question id: 26838

#Unit 10. Ecological Principles

#Question id: 7187

#Unit 5. Developmental Biology

Following statements regarding to feedback loops during limb development.

A. When the limb bud is relatively small, an initial positive feedback loop is established between Fgf10 produced in the mesoderm and Fgf8 produced in the ectoderm, promoting limb outgrowth.

B. As the limb bud grows, the ZPA is established, and another regulatory loop is created by inhibiting the BMP in mesoderm and maintain FGF expression.

C. In anterior region of the limb bud, Fgf8 positively regulates Etv4/5, which in turn repress Shh in this region, further reinforcing the posterior-to-anterior gradient of Shh from the ZPA.

D. In posterior region of the limb bud, Fgf8 positively regulates Etv4/5, which in turn repress Shh in this region, further reinforcing the posterior-to-anterior gradient of Shh from the ZPA.

Which of the following combinations are incorrect?