L13 Regeneration Flashcards
how long does it take for xenopus tail to regenerate
7 days
what tissues present in teh regenerating tail at different time points
axons always present
muscles/vasculature appear later (48-72 hrs)
what biological activities define the different time points of of the regeneration of xenopus tail
early - wound healing / inflamm response
mid - production of blastema like tissue /localised cell prolif
late - vascular/neuronal/muscle regen
what do microarray show
label cDNA diff colours
chip is the antisense with known genes
allow estimation of the gene up reg / down reg dependent on the colour expr
what did microarray experiments show
that genes invovled in metabolism are upreg v quickly after amputation
also emzyme involved in ros incr in reg tail
what did live imagin of xenopus tail show
that ROS levels are inc in regen tail
what is nox
enzyme complex main source of cellular ros
what occurs to tail regen if inh ros
no tail regen
what happen to ros levels in embryogenesis
are high
what occurs whne a reducing egen is applied during embroyogenesis
defect in gastrulation
AP axis/muscle/brain effected
what model org used to test if regen is a return to embryogen state
limb regen in xenopus
what are some of the differences between limb regeneration and limb devleopment
size bigger in regen
more cell types in regen
immune reponse in regen
regen relies on nerves
what are the two strucutres required for regeneration and their roels
AEC - apical ectodermal cap, requires blastema formation
blastem , mesenchymal orgin v prolif , simple growth zone which appears from milieu of cells is able to read pos of pd axis
what are the development strucutres equivalent of AEC and blastema
AER
progress zone
what is th eoutcome of the experiment in which P or D cells graft onto proximal stump
d stays stell on d
p cells go to both sides of limbs
= blastem cells know pos
what is th eoutcome of the experiment in which hand amputated then reinserted with the proximal-distal axis inverted
both cases regow a hand
the blastema only regenrate distal structures
eg - cannont regen shoulder from a elbow
what is prod1
a glycoprotein expressed in a graded fashion in the limv
describe experiment manipulating a distal transformation
overexpr prod1 and graft blastema cells
=d cells go along pd axis
incr retinoic acid treatment can transform elbow to shoulder = cells respond in a dose dependent manner
what signalling pathways involved in regen
hedgehog fgf8 sonic hedehog wnt fgf20
what is the role of shh and fgf8 in regenerating limb
shh at posterior in blastema
fgf8 at anterior in blastema
interaction needed for limb regen
what is the role of wnt in the regeneratign limb
decr after amputation
then incr after 24hrs
as decr nxn at amputation a pr which modulate wnt
what is the role of fgf20 in limb regen
a target of wnt is upreg at regen decr in tadpole with ros inh morphlino of it wound heals but no full regen - req for axial tissue not epidermal
has science been able to regen limb
use factors to decr the immune response
bead with correct signals
results in partial regrowth not perfect regen
