L14 head development Flashcards
where are the nasal placodes in 28-33d of develoment
on frontal prominence
what celluar/dev processes occur to shape strucutres that develop from nasal placodes
what strucutres are they
proliferation
cell migration
maxillary/mandibular/frontal prominence
what do nasal placodes devleop into
pits surrounded by medial and lateral nasal wellings
what do the lateral nasal sweeling develo into
nostril
what do the mandibular processes devleop into
the lower lip
how is upper lip formed
maxillary swelling grows
compresses medial nasal welling
then fuse
what day is the mammalian face recognisabel
47
when did NCC and skull ev
510mya
where cells form the head
ncc
paraxial mesoderm
endoderm
ectoderm
what cells and what process is the neurocranium/vault formed by
intramembraneous ossification within mesenchyme
NC and mesoderm
what cells and what process is the viseroanium/base formed by
intrambnous ossif
Endochondral ossif
NC +mesoderm
what cells and what process is the viscerocranium/facial bones formed by
ncc
intrambnous ossif
what is the differnece between endochondral ossif and intramembraneous ossif
eo - via a cartilage intermediate/slower
what is special abut face dev
from ncc
diff from axial skel
where ncc from and what process imp
developing n.tube migrate to head/neck primordia
EMT
what dictates the migration of ncc
tf
what tf do ncc that migrate to the head expr
neck expr
non-Hox homeodomain pr e.g. Otx
Hox expr
what is the differnece in differentiation between cranial ncc and trunk ncc
trunk can not develop into skeleton precursos eg chondrocytes and osteoblasts
both - melanocytes/neurons/glial/endocrine/connective
where do ncc arise from
at jucntion of neural plate and surface ectoderm
what specifices the postion of the ncc in rhomobomeres
hox code
where do the ncc in teh rhomobomeres migrate to
into mesenchyme of face and branchial arches
diff rhombo contribute diff ba (in segmental streams)
(r1-3=ba1)
what do the experiments transplant wrong rhomobomere into ba what show
if put r4 into ba1 get ectopic arch strucutre
ncc pre pattern
what evidence is there for plastcity in ncc cells
transplant allow to mix with neighbour cell change in gene expr seen
what strucuteres in neck and face do ncc contribute
face - mandibular and maxillary
neck - PA
what intrinsic factors pattern the head
Hox code along the AP axis of BA
eg PA1 no hox, pa2 hoxa2/b2, pa3 etc
dlx code along the DV axis
eg dorsal = dlx1/2, dlx1/2/5/6 etc
ehat the ptype of a hox mut and hoxa2 mut
hox mut - chnage or loss of skeletal strucutres
hoxa2 - dup of ba1 strcutres/inh intrambn ossif
deafness
what ptype of a dlx5/6 mut
loss of facial strucutres and decr bone strucutre
what extrinsic factors involved in the patternign of the head
fgf/bmp/wnt/endothelin
role in inducing specific programmes
what is the role of fgf8 in patternign
nec for craniofacial dev
is a ncc survival factor
gives positional info for lhx6/7 homeodomain
what is the role of bmp in patterning of the head
induces endothelin 1 expr
which induces dlx gene
what is the role of runx2
master regulator for osteogenesis via intramembraneous ossif
what signal intergrte to control regulate runx2
bmp induce edn induce dlx expr
dlx promote runx2
wnt upreg runx2
what the role of sox9
master regulator for chondrogenesis
what is the phenotype of trecher collins syndrome ncc
fail to prolif but do migrate to correct place
what the molecular mechnaism behind the TCS phenotype that results from TCOF1 mut
truncation in treacle pr
treacle has role in rna biogensis
decr treacle = decr prolif as less rna
how can recue tcof1 phenotype
remove one copy of p53
(promotes cell death)
p53 norm decr cell proli via bind sl1 and destabilise the interaction with ubf
what is the ncc ptype in bardet biedl syndrom
ncc fail migr
