Question

Precursors of neural cells (neural tube) are able to separate from the precursors of epidermal cells because: a. All of the above b. Differential adhesion occurs c. E-cadherin expression is decreased in neural precursors d. N-cadherin expression is increased in neural precursors.

Cadherin adhesion proteins are described by the following, except?

	a.	Transmembrane proteins that can interact with cadherins on other cells
	b.	Crucial to the differential adhesion of cell types
	c.	Binding to fibronectin in the extracellular matrix
	d.	Calcium-dependent adhesion molecules

Answer 1

Neural plate is the key development structure of the nervous system. During the formation of neural plate, the ectoderm consists of three cell layers: neural tube (future brain and spinal cord), epidermis (skin) and neural crest cells (connects epidermis and neural tube). Neural crest are transient structures, composed of cells originally located in the dorsal most portion of the neural folds and closing neural tube.
Ans: Differential adhesion occurs.

Cadherins are transmembrane glycoproteins, that mediate calcium dependent cell-cell adhesion through homophillic interactions of their extracellular domains. Interaction with adhesion molecules not only regulates adhesion and motility but also also directly influences activation status - apoptosis and pro-inflammatory and anti-inflammatory in response to the fibroblasts (includes fragments of fibrin and fibronectin) and other cells.
Ans: Crucial to the differential adhesion of cell types.