BSCI430 Exam III - Neural Crest

Where do neural crest cells originate?

From the ectoderm, at the boundary between the neural plate and the presumptive epidermis

What are the derivatives of cranial neural crest cells?

Facial bones and cartilage, cranial neurons and glia, melanocytes, connective tissues of the head and neck

What are the derivatives of cardiac neural crest cells?

Smooth muscle of great arteries, parts of the heart including the aorticopulmonary septum, melanocytes, neurons, connective tissues

What are the derivatives of trunk neural crest cells?

Sympathetic neurons, dorsal root ganglia, melanocytes, adrenal medulla

What are the derivatives of vagal and sacral neural crest cells?

Parasympathetic ganglia of the gut (enteric nervous system)

Which signals initiate neural crest specification?

Wnt and BMP

Name key ectodermal transcription factors involved in early NCC specification.

Gbx2, Zic1, Msx1, Tfap2

What are the neural plate border specifier genes?

Pax3/7, dlx5/6

Name migratory neural crest specifiers.

FoxD3, Sox9, Snail, Sox10

What is EMT and why is it important in NCC development?

Epithelial-to-mesenchymal transition; allows NCCs to delaminate and migrate

What cadherins are inhibited during EMT in NCCs?

E-cadherin and N-cadherin

Which GTPases regulate NCC migration?

RhoA (trailing edge) and Rac1 (leading edge)

What is contact inhibition of locomotion in NCCs?

NCCs avoid forming protrusions at contact points with other NCCs, promoting directional migration

What are the two pathways of trunk neural crest cell migration?

Ventrolateral pathway and dorsolateral pathway

Which molecules inhibit trunk NCC migration through the posterior sclerotome?

Ephrins

What cells arise from the ventrolateral trunk NCC pathway?

Sensory and autonomic neurons, Schwann cells, adrenomedullary cells

What cells arise from the dorsolateral trunk NCC pathway?

Melanoblasts which become melanocytes

Which transcription factor specifies melanoblast fate?

MITF

How does FoxD3 regulate MITF expression?

↓FoxD3 = ↑MITF = melanoblasts; ↑FoxD3 = ↓MITF = neurons/glia

Where do cranial neural crest cells migrate?

Into the frontonasal, maxillomandibular, lateral nasal processes, and pharyngeal arches

What structures do CNCC contribute to?

Facial bones, cartilage, lymphatic organs, endocrine glands in head/neck/chest

How do cranial NCCs migrate?

Collective migration regulated by SDF1/CXCR4, semaphorins, and ephrins

What experiment showed that melanocytes derive from the neural crest?

Transplants in chick embryos by Mary Rawles

What experiment showed adrenal medulla derives from neural crest?

Quail-chick chimeras by Nicole Le Douarin

How can NCC fates be traced experimentally?

Using cell marking (e.g., antibodies, transgenes) or transplant experiments (e.g., quail-chick chimeras)

What mutations affect melanoblast migration?

Mutations in MITF and KIT

What is the role of KIT in melanoblast development?

Promotes migration and survival of melanoblasts