Regulation of apoptosis Flashcards
1. Explain how genetic approaches are used to study programmed cell death in C. elegans 2. Be able to use epistasis analysis to determine gene interactions, ordering and functions in signaling pathways
What is apoptosis?
- active cell death
- requires energy, RNA and protein synthesis
- cleared by phagocytosis
- no inflammation
What is the purpose of apoptosis?
- Sculpting of tissues
- Deletion of entire structures
- Regulation of the neuron number
- Regulation of immune cells
- body’s defence against cancer
What is necrosis?
- Passive cell death
- Cells swell up
- Membrane breaks down
- Cellular contents leak out
- Nucleus disintegrates
- Cell ghosts
- Inflammatory (tissue damage)
What are the stages of apoptosis?
- cell death initiation
- cell corpse
- engulfment
How to decide which of the 15 genes a specific phenotype is? using ced-3 as an example
- transform each of the 15 genes into ced - 3. The correct gene will complement and produce a wild type phenotype
- sequence the allele of all 15 genes in the ced-3 mutant. The correct gene should have a mutation
- find new loss-of function mutants for each of the 15 genes. Mutations in one of the genes should have a phenotype similar to ced-3
What are RNA Interference?
RNA transcript of gene hybridized to is antisense RNA
What are RNAi used for?
- Can engineer a vector to code for both sense and antisense RNAs
- Can use this to target/interfere with specific gene transcripts
What are caspases?
act as dimers
How are caspases activated?
first synthesized as an inactive protease prescursor and later activated by proteolysis at specific aspartate residues
What are gain of function of mutations?
- a mutation that confers new or enhanced activity on a protein
- uncontrolled or promiscuous activity
- increased protein activity
What are some weird genetics?
- haploinsufficient
- dominant negative
What is a dominant negative?
loss of function mutation that is dominant because the mutant protein interferes with function of normal allele
What are the three classes of proteins in an conserved apoptotic pathway
- regulator
- adaptor
- effector
- executioner (sometimes)
What are the pathways initiating apoptosis?
- activation of cell death from inside the cell
- activation of cell death from outside the cell
- these two pathways intersect at the effector caspases
What is an intrinsic pathway?
- when the mitochondria gets effected by some external environment stimulant
- causes cytochrome c release
