Lecture 2- key concepts in early development Flashcards
what is cell lineage
developmental history of a differentiated cell
what is a blastomere
cell type of the early embryo generated by cleavage of a zygote
what is a blastocyst
spherical embryo at the time of implantation
what three tissues does the blastocyst contain and what do they develop into
tropectoderm- precursor of placenta
epiblast- founding tissue of all the embryo
primitive endoderm- covers epiblast surface and gives rise to the yolk sac tissue
what is potency
the ability of a cell to differentiate into one or more cell types
what is totipotency
ability of a cell to give rise to a fully functional organism
embryonic and extraembryonic
what is pluripotency
ability of a cell to develop into all embryonic ,but not extraembryonic , cell types
describe the descriptive hallmark of pluripotency
expression of pluripotency TFs
eg. Nanog, Oct4, Sox2
use in situ hybridisation to detect the mRNA of indicated genes
describe the functional hallmark of pluripotency
pluripotent cells can be grafted onto kidney of host mouse and give rise to teratocarcinomas (tumour containing all cell types)
verify using a functional assay
what are the first specialised precursors, generated by gastrulation
ectoderm
mesoderm
endoderm
how is a cells identity predicted in gastrulation
due to location of cell
either upregulation or antagonisation of different signals
what is the purpose of the primative streak
Initiates gastrulation
Establishes body axes
Guides cell migration to form specific tissues
Regulates molecular signals for differentiation
what is the primative streak initiated by
Wnt signalling
how are epithelial cells characterised
tight junctions
polarized morphology
describe the epithelial to mesenchymal transition and what is achieves
where cells lose their regular apperance and become migratory
allows for growth and specification
what is a progenitor
a cell that proliferates for a limited number of cycles before differentiation
what type of progenitor cells are NMPs
bipotent
what do NMPs give rise to and where does this occur
paraxial mesoderm or spinal cord in the posterior of embryo
what does NMP stand for
neuromesodermal progenitor
what type of formation do NMPs drive
axis formation
which signals are elevated in the NMP niche
WNT and FGF
how can we define NMPs experimentally
using descriptive gene markers to observe T and SOX2 co expression
T+ and SOX2 - -> paraxial mesoderm
T- and SOX2 +. -> spinal cord
what is the effect of a defect in NMPs
spina bifida
what kind of progenitors are neural crest cells
multipotent
what do the different layers of the neural crest form
superficial= pigment skin cells
intermediate= sensory ganglia
medial = sympathetic ganglia
what kind of progenitors are neural stem cells
bipotent
what can neural stem cells give rise to
glia or neurons
what is the self renewal niche of neural stem cells
SOX2 + and RC2+
what is the glial niche of a neural stem cell
GFAP +
what is the neuronal niche of a neural stem cell
TUJ1+
what type of progenitor are haematopoietic stem cells
multipotent
if you remove the whole blood system in mice and then introduced HSCs what would happen
the whole blood system could be reconstituted
