L16 tooth development

Question 1

where do enamel cell originate

Answer 1

ectodermal ridge

Question 2

where do dentine cell origniate

Answer 2

ncc

Question 3

why tooth development good eg to study

Answer 3

reciprocal interaction m and e (2 germ layer orgin)
bmp4 signal ised various stages
can study without lethal effect

Question 4

what is the process of tooth morphogenesis

Answer 4

thickening of placode = E11.5
bud - with the M condesing around epi = E13.5
cap - extends further = E14.5
bell - condensing M has enclosed epi and the
differentiation of denitne vs enamel occurs =E18.5

Question 5

where is the odontogenic potenital before day 12

Answer 5

in epi

epi says m make tooth

Question 6

where is the odontogenic potential after day 12

Answer 6

in mesenchyme

m returns signal says epi make tooth

Question 7

how does th eodontogenic potential differ to hari follilcle initiation

Answer 7

in hf is m then epi

Question 8

what is the marker for tooth location

Answer 8

pax9

Question 9

how is pax 9 set up

Answer 9

epi and m interaction
remove ecto b4 d 11 no pax9
only when replace with cranium ecto can save

Question 10

what signals dictate spatial location of pax9

Answer 10

fgf act

bmp inh

Question 11

what is fgf8 in positive feedback iwht in the epi

Answer 11

pitx2

Question 12

role of dynamic bmp4

Answer 12

moves with time

allows second wave of pax9 induction

Question 13

what other tf does fgf8 act in the oral mesenchyme

Answer 13

lhx6/7
nec not sufficient
role in tooth location

Question 14

what is thr ole ofm gsc tf in the tooth location

Answer 14

expr after lhx6/7
pos reg with fgf8
but exclude from lhx6/7 domain
gives the no form tooth identitiy

Question 15

what tf can be viewed jaw didivided into to give tooth location

Answer 15

pax9 = tooth 
gsc = no tooth

Question 16

what do cross species epi and m combinations show about teeth in birds

Answer 16

oral m does not produce a signal
oral epi does
can induce mineralised strucutre in hen

Question 17

what signals norm expr in hen mouth different from mammal

Answer 17

bm4 not expr

fgf8 is

Question 18

what suggests a role for wnt in tooth dev

Answer 18

as if act b cat in chick induce tooth dev

Question 19

what are the two tf for tooth identity

Answer 19

msx1
barx1
both expr in dental mesenchyme

Question 20

what tooth fate do msx1

barx1 give

Answer 20

incisor (proximal)

molar (distal)

Question 21

what is signals controlm the expression of barx1

Answer 21

fgf8 induce

bmp4 inh

Question 22

what the ptype if ko bmp4

Answer 22

incisor to molar

Question 23

what are enamle knots

Answer 23

singalling centres of teeth
important for molar morphogenesis
do not prolif

Question 24

what are the first singal rel by enamel knots that drive prolif

Answer 24

BMP and FGF

Question 25

role of fgf4 in molar morphogensis

Answer 25

involution of dental epi

form cusps

Question 26

role of shh and wnt in epi

Answer 26

set up boundary oral and dental
wnt7b in non dental inh shh
shh induce by bmp4

Question 27

what does a mut in the EDAR pathway result in

Answer 27

ectodermal dysplasia
abn dev of ectodermal appendages
save if give pregnant mouse recombinant form of eda pr

Question 28

edar mut in tooth dev ptype

Answer 28

no edar
no enamel knot
no cusps

Question 29

what are ameloblasts

Answer 29

the cell types in tooth that produce enamel

derived from ecto

Question 30

what are odontoblasts

Answer 30

cells in tooth that prodcue dentine

derive from ncc and m

Question 31

what the ptype of ameloblast enamel in bmp4 ko/overexor

Answer 31

ko = no enamle

overexpr- ectopic ameloblasts

Question 32

what the role of runx2 in tooth

Answer 32

in the m

controlm odontoblast and ameloblast no

Question 33

what is the role of fgf4/8 in stem cell niche of incisor

Answer 33

promote proliferation and survival