Lecture 11- Cell Death in Development Flashcards
pathological cell death
triggered by external factors such as oxidative stress, involves cell rupture and inflammatory response
programmed cell death
developmental process, cell shrinkage/DNA concentration/cell fragmentation, phagocytosis of fragments
general name for proteins controlling apoptosis
caspases
2 types of caspase
initiator and executioner
initiator caspase mechanism of action
form a dimer
autoproteolytic cleavage, which creates the active form
what do initiator caspases do
activate executioner caspases
executioner caspase mechanism of activation
also forms a domer, cleavage by initiator caspases to make active form
how are mitochondria involved in apoptosis
BCL2 mitochondrial membrane proteins regulate initiator caspase activity- usually inhibits apoptosis
what can trigger initiator caspases
reactive oxygen species/cytochrome C leaking from the mitochondria
examples of caspase-independent cell death
linker cell-type death, may occur in vertebrate sex determination to the bipotential gonad cell
autophagy, doesn’t normally cause cell death though
3 techniques for studying cell death
DNA staining e.g. DAPI- can see fragmented genetic material
live/dead staining using a marker which usually can’t cross cell membranes but can during apoptosis
anti-caspase antibodies in already dead tissue
example of where cell death might occur
making a vertebrate hand, cell death between digits
what is the system which promotes apoptosis between digits
Msx/BMP
how do webbed appendages form
repression of the system which usually causes inter-digit cell death
another system which has a lot of cell death
insect nervous system- whole hemilineages can be killed
