Bio 325 Exam 3

Front 1

Principal mesoderm territories

Back 1

Intermediate Mesoderm
Chordamesoderm
Paraxial Mesoderm
Lateral Plate

Front 2

Intermediate Mesoderm Derivative

Back 2

Kidneys
Gonads

Front 3

Chorda-Mesoderm Derivative

Back 3

Notochord

Front 4

Paraxial Mesoderm Derivative

Back 4

Head and Somite

Front 5

Lateral Plate Mesodetm Derivative

Back 5

Splanchnic Mesoderm(Outer) Circulatory Mesoderm
Somatic Mesoderm(Inner) body Cavity
Extra Embryonic

Front 6

Somite Tissue Derivatives

Back 6

MEDSS
Myotome(Skeletal Muscle)
Endothelial
Dermatome(Dermis, Skeletal Muscle)
Sclerotome(cartilage)
Syndotome(tendons)

Front 7

chordin

Back 7

used to suppress BMP, binds BMP

Front 8

Paraxis

Back 8

essential for somite formation

Front 9

Why are Somites Important to study?

Back 9

They are essential in segmenting the body, gives you a foundation for body development

Front 10

What happened when adding Noggin near Lateral Mesoderm?

Back 10

Ectopic somite formation, infers BMP influence on somite formation

Front 11

What did the quail somite transplant experiment show?

Back 11

showed predicted boundary was determined

Front 12

What signaling pathway is responsible for segmentation of somites?

Back 12

Notch, important in generating boundaries

Front 13

Notch Signaling

Back 13

Juxtacrine Signaling, one cell with delta And cell with notch bind, causing notch tail to be severed by protease. severed tail becomes part of transcription complex

Front 14

What happens when delta like 3 is knocked out of mouse embryo?

Back 14

Multiple mistakes in somite and rib formation, lethal mutation

Front 15

Clock and Wave

Back 15

Hairy1 is expressed in waves and are timed to condense and pinch off somites

Front 16

lunatic fringe

Back 16

regulated by notch, responsible for cells to respond to delta signal, can be used to drive GFP formation that is short lived. enabling to see clock wave.

Front 17

Determination Front

Back 17

Where FGF and WNT are no longer expressed, critical for specifying boundary formation because notch will remain active

Front 18

Ephrin A4

Back 18

activated by hairy1, tells neighbring cells to make somite boundary, is expressed in anterior half of somite

Front 19

Axin

Back 19

inhibits Wnt, part of negative feedbackloop where wnt turns on axin as well as notch, axin inhibits, but fgf is still turning on wnt, so it cycles

Front 20

Mesp2 and Lefringe

Back 20

part of negative feedback loop that supresses notch

Front 21

MET

Back 21

Mesenchymal to Epithelium Transition. eph ligand become epitheslium surrounding a mesenchymal center

Front 22

What happened when presomitic mesoderm was transplanted to another region?

Back 22

determined to be what it would have had it not been removed

Front 23

How many HOx clusters do vertebrates have? why?

Back 23

4, by coping and evolution overtime

Front 24

paralogs

Back 24

the genes on the clusters that correspond to one another act similarly, like a1 is similar to b1, c1 and d1

Front 25

Hox Code Hypothesis

Back 25

if you are a certain type of mesoderm spatially, you are going to express a certain combination of hox genes

Front 26

What happens when you knock out hox 10 on mouse embryo(Homeotic Transformation)

Back 26

you see the cells that should be lumbar become thoracic, they think they are more anterior

Front 27

Retonic Acid responsibility in somites

Back 27

It posteriorizes, opposite of homeotic transformation

Front 28

Role of Retnoic Acid

Back 28

It converts the somite to a more posterior structure

Front 29

EMT

Back 29

Epithelium to Mesenchyme Transition

Front 30

MET

Back 30

Mesenchyme to Epithelium Transition

Front 31

2 day Somite features

Back 31

tight ball but specfied cells with lower left quandrant destined for sclerotome

Front 32

3 day somite features

Back 32

EMT, more heavily in scelrotome Region, you see it spreading out a bit

Front 33

4 day Somite features

Back 33

Scelrotome completely mesenchyme
dermamytome differentiates to abaxial, primaxial dermamyotome lips and a central dermatome
couch like structure
there is also primaxial and abaxial myotome cells fated to muscle, the lips guide

Front 34

late 4 day somite features

Back 34

extended couch structure
layers of sclerotome and myoblasts, ypu can see central myotome region in dermatome which give rise later to satelite cells

Front 35

what does tagging Prox1 help us to see?

Back 35

Abaxial muscle

Front 36

What is the effect of SHH on on Somites?

Back 36

Turns on Pax1 gene and differnetiates to sclerotome

Front 37

What secretes shh?

Back 37

notochord

Front 38

What does noggin do? Where is it Somite formation?

Back 38

Blocks BMPS, notochord secretes it, protects ventral half from BMP4, secreted by Epidermis

Front 39

Nerotrophin3 and Wnt 1

Back 39

Secreted by neural tube, and inudces Dermatome formation

Front 40

Wnt1, Wnt3a and shh

Back 40

Secreted by neural tube and notochord respectively, induces Primaxial Myotome by expressing Myf 5

Front 41

Wnt, Bmp4 and FGF5

Back 41

Wnt from epidermis, and BMP4, FGF5 from Lateral Plate Mesoderm induce Abaxial Myotome by expressing Pax3 and Myod

Front 42

General Steps in Muscle Differentiation

Back 42

a) myotome cells differentiate, by wnt, ssh-> myoD Myf5
b) multiply and divide, by FGF for growth
c) Multiplicaton stops, cells allign, by myogenin
d) myotube formation, cellfusion
e) myotube maturation, last myoblasts fuze
f) maturation of muscle fiber

Front 43

MRFs

Back 43

Myogenic Regulation Factors, organized helix loop helix, with DNA Binding domain

Front 44

E-Proteins

Back 44

Counterparts to MRFs, also Helix loop helix formation, they dimerize and Activate Genes

Front 45

List MRF genes

Back 45

Myod, myf5,mrf4 and myogenin

Front 46

Knockouts of MRFS

Back 46

knock out single genes , there is no muscle defects except with myogenin, which as less muscle than normal, it takes a triple KO in order to have serious defects

Front 47

General order of MRF gene action

Back 47

myoD and myf5 activate eachother and themselves(positive feedback), These activate MRF4 and shortly after FGF is introduced bringing myogenesis to the multiplication stage,
Once FGF is degraded, MRF4 activate Myogenin, the key component in terminal differentiation of muscle

Front 48

Myostatin

Back 48

Regulates Muscle growth by stopping muscle cells form dividing.

Front 49

What happens if Myostatin is knocked out?

Back 49

Bulk Up

Front 50

How is the Myostatin gene knocked out?

Back 50

insert Stop codon by changing a base through genetic recombination.

Front 51

In the Belgian Blue Cow, how did it lose myostatin?

Back 51

Deletion

Front 52

What family of proteins is Myostatin a part of?

Back 52

TGF B, activates smad 2,3 pathway

Front 53

what stage of muscle differentiation is myostatin the most active

Back 53

Multiplication stage, puts a break on growth and multiplying

Front 54

Scelrotome formation

Back 54

forms vertebra from two pieces of adjacent sclerotome regions/cells, this is done because of the nerves growing out if the spine

Front 55

What does the scelerotome contribute to besides bone?

Back 55

the aorta, syndotome, which forms tendons

Front 56

Scleraxis

Back 56

gene that forms tendons

Front 57

How is the Syndetome induced?

Back 57

by the myotome cells with FGF, bringing about scleraxis and ultimately tendons

Front 58

Stylopod

Back 58

Upper Limb, arm humerus, leg femur

Front 59

Zeugopod

Back 59

Lower Limb, arm ulna and radius
leg Tibula, fibula

Front 60

AutoPod

Back 60

hand/feet metacarpals and digits

Front 61

What specifies the position of limbs?

Back 61

Hox genes in the lateral plate mesoderm, specifically somatic side,

Front 62

which hox genes are responsible for limb position and what happens when knocked out?

Back 62

b8, c8, d8. shift in fate towards more anterior. the limb is shifted by one segment

Front 63

Apical ectodermal ridge

Back 63

leading edge of the Limb bud, a key lining of endothelial cells guiding limb bud development

Front 64

Trematode Cysts

Back 64

generate extra limbs by going into limb buds and splitting it up

Front 65

step 1: Limb Development

Back 65

FGF10 is expressed widely in LPM. Wnt8c is then expressed which stabilizes and focuses FGF 10.

Front 66

step 2: Limb Development

Back 66

FGF10 is fouces in a smaller band on LPM. WNT 2b keeps this area expressing FGF10

Front 67

Step 3: Limb Development

Back 67

FGF10 induces the ecotderm nearby to produce Wnt3a, which in turns induces FGF 8 which then loops back to LPM promoting FGF10 stabilization.

Front 68

Tbx5

Back 68

transcription factor expressed in mesoderm of anterior forelimb

Front 69

Tbx4

Back 69

transcription factor expressed in mesoderm of posterior hindlimb

Front 70

which somite is line that determines hind or fore limb in the chicken? What happens when you put bead at this location?

Back 70

somite 22
chimera limb is developed

Front 71

What happens when tbx4 is forced in forelimb bud mesoderm?

Back 71

convert wing to leg, same thing happens with tbx5 but reverse

Front 72

What are the four functional regions of the limb bud?

Back 72

1) Apical Ectodermal Ridge(AER)
2) Progress Zone(PZ)
3) Zone of Polarizing Activity(ZPA)
4) Dorsal Ectoderm(DE)

Front 73

What happens with AER is removed or put extra on it?

Back 73

Loss stops limb development
Gain duplicates digits

Front 74

What happens when Leg Mesenchyme is transplanted to where arm mesenchyme should be?

Back 74

becomes a leg, because it expresses tbx4

Front 75

What happens when you replace Leg mesenchyme with nonlimb mesenchyme?

Back 75

AER regress and limb development ceases

Front 76

Progress Zone(PZ)

Back 76

located behind apical ectodermal and receives FGF from AER to continue grow. Proximal and distal growth

Front 77

What regulates the length of limb?

Back 77

Progress Zone is responsible, age determines what structures to form

Front 78

What are two Models for PZ explanation of distal growth?

Back 78

1) Cells somehow count how many times it has divided, PZ leaves cells behind that know how long they've been away from the PZ
2) Young Bud determines the tissues early on and expands overtime

Front 79

What are the three models for limb development?

Back 79

Process model, cells get left behind
early stage, progression, cell boundaries set early
Reaction diffusion

Front 80

How are limb bone elemts patterend?

Back 80

paralogous hox genes

Front 81

Hox gene limb map

Back 81

9+10 sylopod
10+11 zuegopod
11,12,13 Autopod

Front 82

What happens when you Knock out hox 11 in regards to limb development?

Back 82

Ulna And radius are mising

Front 83

What happens when you Knockout hox 13 in regards to limb development?

Back 83

autopod, digit fusion

Front 84

hox genes and limb development

Back 84

Where Hox genes begin to be expressed and this area grows with the limb bud where the higher hox genes are expressed more distally and lower ones more proximally

Front 85

Zone of Polarizing Activity

Back 85

Responsible for Anterior/Posterior direction of limb, located at posterior end of limb bud, helps to organize up and down oreintation using shh

Front 86

Inactive state of shh pathway

Back 86

Patched and Smoothened Proteins in membrane are doing nothing and protease cuts ci/gli in half, this forms a repressor

Front 87

active state of shh pathway

Back 87

binding of hedgehog to Patched, activates smoothened and inhibits proteases and ci activates genes

Front 88

How does the ectopic digits in mouse happen in relation to shh?

Back 88

mutation of of enhancer that represses shh in certain areas beocmes an activators

Front 89

B-Galactsidase

Back 89

reporter gene, was used to see expression of shh

Front 90

shh patterning in regards to concentration and time of expression

Back 90

Digits 4 and 5 have the most shh exposure, as you go more anterior there is less and less influence

Front 91

What protein is repressing anterior digits from forming?

Back 91

BMP, it helps to make cells respond to Gli

Front 92

What happens when you cut pieces of tissue away from inbetween developing digits?

Back 92

fingers develop more anterior, like loss of shh, index finger looks like a thumb, but really is losoig BMP which in turn makes the cells lose competence to respond to ssh

Front 93

BMP role in digit formation

Back 93

induces apoptosis and increases competence to shh

Front 94

How AER and ZPA help each other grow?

Back 94

by maintaining FGF4 and FGF8 for the AER and shh for the ZPA

Front 95

What does the Dorsal Ectoderm express?

Back 95

Wnt7a

Front 96

what happens when wnt7a is knocked out?

Back 96

ventralization of the dorsal side, ventral on both sides

Front 97

Gremlin

Back 97

inhibits BMP, duck webbed feet

Front 98

What are the four ways to regenerate?

Back 98

1) Stem Cell Mediated
2) Epimorphosis
3) Morphallaxis
4)Compensatory Regeneration

Front 99

Stem cell mediated Regeneration

Back 99

planaria as an example has stem cells throughout the body and regenerate any part cut off, can be seen by piwi, stem cell marker

Front 100

Compensatory Regeneration

Back 100

differentiated cells replace themselves by dividing, happens in mammalian liver

Front 101

Whats the evidence of blastema knowing position?

Back 101

blastema transplant showed it healed the daMAGED PART OF THE DONOR EVEN THOUGH THE RECEIPIENT was cut off at different location

Front 102

blastema

Back 102

a group of tissue right at cut site,
its guides regeneration

Front 103

Epimorphosis

Back 103

cells dedifferentiate, they gain stem cell factors. marker msx1. they proliferate and redifferentiate back to the cell type they were.
regeneration that regrows the missing parts by "filling in" the positional system

Front 104

Morphallaxis

Back 104

REajusts positional values then re differentiates

Front 105

Stages of limb regeneration

Back 105

1) Amputation
2) Healing-epidermis heals
3) Dedifferentiation- blastema forms
4) Cone Stage- dedifferniated cells proliferate
5) Palette Stage-newly created cells that are more proximal begin to redifferentiate, blastema looks like palette
6) Notch Stage-right before digits reform, like a notch/nub
7) Digit Stage

Front 106

Are dedifferentiated cells pluripotent?

Back 106

no, they act like stem cells but they are still determined to the tissue they came from

Front 107

What role does a nerve play in limb regeneration?

Back 107

if you denerve the limb, and then cut it off, the limb won't regenerate, proteins prod1(CD59) and nAG

Front 108

nAG

Back 108

stimulates regeneration

Front 109

prod1 expression

Back 109

expressed more proximally in blastema.

Front 110

What happens when you add REtnoic acid to balstema?

Back 110

blastema will grow as if it was right next to the body, a whole limb, RA is probably playing a role

Front 111

i cells

Back 111

stem cells for regeneration in hydra