Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

ANAT 381 Experimental Embryology > Segmentation in Vertebrate Embryos > Flashcards

Segmentation in Vertebrate Embryos Flashcards

1
Q

A “module” of the embryo that consists of a group of adjacent cells that do not mix with cells from neighbouring compartments is defined as what?

A

A compartment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Cells in a compartment display what similar trait?

A

The same gene expression profile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

A border/region between two compartments that cells do not cross is defined as what?

A

A compartment boundary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Some clones of cells within a compartment have _____________ or ______________ borders

A

Jagged; straight

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the two functions of the boundaries?

A

Prevent intermingling of cells and provide positional information to flanking cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How can compartment boundaries be visualized?

A

With a lineage marker

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the different adhesion properties at compartment boundaries?

A

Quantitative and qualitative

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How does a field of cells become subdivided?

A

Their interpretation of a morphogen gradient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What induces transcription factors, adhesion affinities within a field of cells?

A

Morphogen gradient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Subdivisions are maintained and refined by what?

A

Local cell-cell interactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How is a boundary formed in a field of subdivided cells?

A

Two distinct populations lead to the formation of specialized cells at borders

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How does the boundary influence surrounding cells?

A

Long-range signaling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Where do organizers form?

A

At compartment boundaries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What initiates the segment polarity genes in Drosophila?

A

Stripes of pair-rule genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is a parasegment?

A

Anterior end of one stripe to anterior end of next stripe

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Where is Wingless expressed in Drosophila?

A

Between the stripes of Eve and Ftz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How many cells expressing Engrailed are found per stripe of Eve and Ftz?

A

One

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Cell expressing _____________ is the posterior cell of each segment

A

Engrailed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Segments allow for repetition of ________

A

Form

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are somites?

A

Masses of mesoderm formed from presomitic mesoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How many pairs of somites are formed in chicks?

A

55 pairs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Somites differentiate to give rise to which structures?

A

Dermis, skeletal muscle and vertebrae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Which part of somite differentiation gives rise to muscle, endothelia, cartilage, connective tissue and dermis?

A

Dermomyotome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Which part of somite differentiation gives rise to vertebral column, meninges, connective tissue and ribs?

A

Sclerotome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Signaling of what molecule is important for paraxial mesoderm specification?

A

BMP

26
Q

What experiment was done to test the role of BMP signaling in somite formation?

A

Transplant Noggin-secreting cells into LPM
Formation of somites

27
Q

What experiment was done to observe the role of Tbx6 in paraxial mesoderm differentiation?

A

Tbx6 knockout in mice led to paraxial mesoderm transformation into neural tubes

28
Q

How do somites know when and where to form?

A

Embryological clock measures development
Rate of somite segmentation must be coordinated with overall development and occur in parallel on both left and right sides

29
Q

What patterns neuromesodermal progenitors during paraxial mesoderm development?

A

Antagonistic signals along the anterior-posterior axis

30
Q

Which antagonistic signal is more prominent at the anterior axis of NMPs?

A

Retinoic acid

31
Q

Which antagonistic signal is more prominent at the posterior axis of NMPs?

A

Fgf8

32
Q

Which molecule is expressed at the boundary of low RA/low Fgf8 and indicates where the next somite will form?

A

Mesp

33
Q

Signaling of what molecules regulates epithelialization during somite boundary formation?

A

Ephrin

34
Q

Place the events of epithelialization during somite boundary formation in order
a. Upregulates EphA4 in anterior half
b. Mesp restricted to anterior half of S-1
c. Triggers epithelialization and formation of a boundary
d. EphA4 upregulates its binding partner ephrinB2 in presumptive posterior S-0

A

b, a, d, c

35
Q

What signaling pathway controls when the somite boundary is formed?

A

Notch signaling pathway

36
Q

Which molecular oscillator in the PSM modifies Notch signaling to regulate the pace of vertebral segmentation?

A

Lunatic Fringe (Lfng)

37
Q

What is the mechanism of Notch signaling in boundary formation?

A

Notch target gene oscillates in segmentally defined pattern
Mesp (Notch target) in anterior half represses Notch activity in anterior half
Genes that form the boundary are activated
High Fgf8 in posterior end prevents cells from being competent to respond to Notch signal

38
Q

The spatiotemporal collinearity of Hox gene expression in the presomitic mesoderm is correlated with what?

A

Chromatin remodelling

39
Q

What happens when you transplant presomitic mesoderm from region that would normally form thoracic vertebrae caudal to the 1st somite in a younger embryo of chick?

A

Formation of ribs in the neck vertebrae (gain-of-function anterior to posterior transformations)

40
Q

What happens if cervical somites were transplanted into thoracic region?

A

Ribs don’t form on vertebrae derived from cervical somite

41
Q

True or false: Snakes have almost 1-2x more somites than vertebrae

A

True

42
Q

Why do snakes have more somites than mice?

A

They have 3-fold more oscillations in Lunatic Fringe expression in the PSM

43
Q

Identify the definitions to the axis in the human body
a. Tips of digits
b. Closest to the body
c. Back of the limb (top of the foot)
d. Front of the limb (bottom of the foot)
e. Thumb/big toe
e. Pinky/little toe

A

a. Distal
b. Proximal
c. Dorsal
d. Ventral
e. Anterior
f. Posterior

44
Q

In the limb bud, the posterior LPM and somite cells form which structures?

A

Posterior LPM forms skeletal precursors and somite cells form muscle precursors

45
Q

Between which days do the limb buds continue to grow in mice?

A

9 and 11

46
Q

What is visible at E11 of the formation of the limb buds in mouse?

A

Apical ectodermal ridge (AER)

47
Q

What event occurs for the interdigit region to be formed?

A

Programmed cell death

48
Q

Digit growth in human embryo occurs between which days?

A

48 and 56

49
Q

Where is limb bud formed?

A

Outpouching of lateral plate mesoderm at the “correct” position along the AP axis

50
Q

What do hox genes expressed along AP axis regulate?

A

Expression of retinoic acid and Fgf

51
Q

RA and Fgf8 act as antagonistic signals to induce ___________ expression

A

Tbx5

52
Q

What is Tbx5 responsible for?

A

Position of forelimb bud

53
Q

The forelimb field belongs to which hox gene?

A

Hoxc6

54
Q

What is RARE?

A

RA response element

55
Q

What is Rdh10 important for?

A

Synthesis of retinoic acid

56
Q

What experiment was done to observe the role of RA and Fgf8 along the AP axis?

A

In situ hybridization for RARE expression in the forelimb field of the wild type and mutant Rdh10
In situ hybridization for Fgf8 in the heart and caudal progenitor zone of the wild type and mutant Rdh10

57
Q

What were the results from the experiment with Rdh10 mutant?

A

RARE was expressed in wildtype Rdh10, but not in mutant Rdh10, indicating that RARE is found in the heart
Fgf8 was expressed in both wildtype and mutant Rdh10, indicating that Fgf8 is found in the heart and caudal progenitor zone

58
Q

Tbx5 was expressed in wild type Rdh10, but not in mutant Rdh10. What is the significance of this?

A

Tbx5 requires RA signaling to be induced

59
Q

What signals position of LPM outgrowth?

A

Fgf10

60
Q

Between RA and FGFs, which one induces ectopic limbs?

A

FGFs

ANAT 381 Experimental Embryology (24 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions