Neural Crest 1 Practice Flashcards

75 practice flashcards covering neural crest specification, migration pathways, fate restriction models, and experimental methods based on the provided lecture notes.

What is the neural crest often referred to as in developmental biology?

The $4^{th}$ germ layer

Which two specific lineages from the neural crest will this lecture focus on?

Neural derivatives and glial derivatives

Besides neural and glial cells, which cell type is highlighted as a derivative of the neural crest?

The melanocyte

Where is the neural crest formed along the length of the embryo?

In the midrange and to the tail

Why are the vagal and sacral regions of the neural crest special?

They generate neurons and glia that control gut mobility

What unique fates are created by the head region of the neural crest?

Skelogenic fates

Trunk neural crest cells migrate along how many distinct pathways?

$$2$$

Which cell lineage typically follows the dorsal-lateral stream under the epidermis?

Pigment cells (melanocytes)

What are the three main destinations of the ventral migration stream in the trunk?

Sensory, enteric, and autonomic ganglia

In which part of the mesodermal derivatives (somites) do neural crest cells migrate?

The anterior period (they do not migrate in the posterior region)

Which family of molecules prevents migration of neural crest cells in the posterior somite?

Semaphorins

What were the two traditional views regarding when neural crest cells know their fate?

Direct fate restriction and Progressive fate restriction

Who proposed the 'Direct fate restriction' model?

Bronner (supported by Anderson)

According to the 'Direct fate restriction' model, when are cells told what to do?

Initial multipotent cells migrate and are told what to do only in their target location

Who are the primary proponents of the 'Progressive fate restriction' (PFR) model?

Le Douarin and Jim Weston

In the PFR model, how do environmental signals affect migrating progenitors?

Progenitors become partially restricted as they migrate, becoming more determined based on signals

What is currently considered the 'textbook view' of neural crest development?

Progressive fate restriction (PFR)

According to chick fate-map data, when might cell fates be chosen?

Before delamination

Mouse clonal data suggests cells retain multipotency at what stage?

Early migration

What does single-cell RNA profiling from $2019$ suggest for the Peripheral Nervous System (PNS)?

Progressive fate specification

Why is showing genes for a particular fate not the same as addressing its potency?

Gene expression indicates the way cells are being pushed by their environment, not necessarily their potential

What are two traditional methods used to determine the fate of neural crest cells?

Neural tube grafts and In vivo labelling

What is a major technical limitation of neural tube grafts for determining multipotency?

You are transplanting large numbers of cells, which does not show the potency of individual cells

What happens when vagal crest is transplanted into a posterior trunk region?

The cells are reassigned and develop into what the local trunk cells are doing (plasticity)

What method involves labeling a small group of cells to identify all resulting cell types?

Cell lineage analysis

In chick embryos, which side of the neural tube is typically labeled via electroporation?

One side of the spinal cord

At what somite stage range is chick neural tube labeling often performed?

$15-25$ somites

Which neural crest cells populate the most ventral regions in the chick spatiotemporal model?

The earliest cells to delaminate

Late-delaminating cells in the chick populate which location and form which cells?

The dorsal region to form melanocytes

What happens to the Sox9 domain as cells pop out of the neural tube?

The domain gets smaller and smaller as the neural crest is depleted

In chick spatiotemporal mapping, where are cells from the middle stage often found?

Dorsal root ganglia

Does 'Fate restriction' in fate maps always equal 'Potency restriction'?

No

What genetic labeling technique is used for clonal analysis in mice?

Rainbow labeling

How does the 'Rainbow' method distinguish different clones?

Individual clones are labeled with unique mixtures/levels of red and green proteins

What was the definition of 'multipotent' used in the mouse Rainbow study?

Ability to generate at least $2$ cell types

The $2019$ mouse single-cell RNA studies analyze how many cells?

Thousands of cells recognized using algorithmic tools

In the new progressive fate restriction model, how are decisions described?

As 'splits' or bi-potency decisions between progenitor paths

In the cluster diagram of single-cell data, what does a dot represent?

$1$ cell

What is indicated if two dots are close together in a cluster diagram?

Their transcriptors (transcriptional states) are similar

What is the 'Hub' state in the single-cell RNA model?

A shared state where NCCs and SCPs converge before differentiation

Where is the 'Hub' state located in terms of adult anatomy?

Associated with nerves (where adult neural crest stem cells are found)

What color represents enteric neurones in the cluster differentiation diagram?

Pale blue

What color represents enteric glials in the cluster differentiation diagram?

Orange

Developmental paths always go from which part of the cluster diagram?

From the center (hub) to the periphery

Which model suggests progenitors move through sub-states biased toward individual fates?

Cyclical Fate Restriction model

In the Cyclical Fate Restriction model, does a progenitor lose multipotency while biased?

No, it retains multipotency while cycling through states

What alters the relative balance of time spent in a specific sensitised sub-state?

Environmental signals

The Cyclical Fate Restriction model produces what kind of transcriptional behavior?

Oscillations in the expression levels of key transcription factors

How does the Cyclical model explain the 'impression' of PFR?

Dynamic regulation creates the look of PFR, but multipotency is actually retained

According to the Cyclical model, what is key to NC fate specification?

Environmental signals

What happens to migratory cells in pro-ganglial environments according to the Cyclical model?

They become strongly biased to sensory or autonomic ganglial fates

Are specification and multipotency considered incompatible in the Cyclical model?

No, they are not incompatible

Cells accumulating in ganglia are biased toward which two fates?

Neuronal and glial fates

What does a cell 'want' to be if it spends most of its time in a 'yellow' transcription state?

Yellow-fate derivative (e.g., neuroblast)

What does N and G stand for in the context of bipotency?

Neuronal and Glial

What does the 'brown area' in the summary diagram represent?

Early crest cells

What does the 'grey area' in the single-cell diagram represent?

The 'Hub' (shared state)

What generates the array of cell types in the 4th germ layer?

Multipotent neural crest cells

Which region's crest is special for producing pigments and skelogenic fates?

Head region

Where in the somite do crest cells specifically intermingle?

The anterior period

What happens to the DNA injected during chick electroporation?

An electric current drives it into one side of the spinal cord

Which marker is mentioned as a way to observe the shrinking neural crest domain?

Sox9

What is the key difference between fate maps and potency experiments?

Fate maps show what a cell normally becomes; potency experiments show what it is capable of becoming

How many cell lineages typically come from a single bipotent progenitor 'split'?

$$2$$

According to the transcript, how do transcriptional programs lead to cell commitment?

Through co-activation and repulsion of programs

Which model emphasizes that the specification process is highly dynamic?

Cyclical Fate Restriction model

What controls the shift from ventral to dorsal derivatives in the chick fate map?

Timing of delamination

What do the arrows in cluster diagrams suggest about a cell?

Where a cell will be going next in time

In the context of NCSCs, what does the abbreviation stands for?

Neural Crest Stem Cells

Which paper used clonal labelling to show a shift toward melanocytes?

The clonal labelling study in the chick (mentioned on Page 3)

How are individual cells identified as part of the same clone in Rainbow embryos?

They share the exact same levels and mixture of colored proteins

What is the result of a cell being pushed into a 'sensitized' state?

Local specification or 'apparent partial fate restriction'

What provides the bias for the oscillations in the Cyclical model?

Local environment (e.g., pro-ganglial environment)

What is the primary role of transcriptional oscillations?

Retaining multipotency while allowing variable gene expression

What is the outcome for cells that delaminate first in the chick model?

They populate the most ventral region

The ventral stream

These cells migrate downwards through the embryo to form sensory neurons as well as autonomic and sympathetic ganglia.

The dorsal/lateral stream

These cells migrate just underneath the epidermis to become pigment cells (melanocytes)

Trunk neural crest cells

Specific regional population of multipotent neural crest cells that form along the length of the developing embryo

What are the two distinct streams that Trunk neural crest cells migrate down

The Ventral and Dorsal streams.