Novick and Sheckman Flashcards
what year was novick and schekmans experiennt conducted?
1980
what genes were identified in novick and schekmans experiment?
- SEC GENES
- 23 gene products required to ER-PM trafficking
- classified from A to E
what were A to E classifications of the proteins that novick and schekman identified?
A- accumulate in cytosol B-accumulate in the ER C- accumulate in ERGIC vesicles D- accumulate in golgi E- Accumulate in post-golgi vesicles (secretory vesicles)
why could novick and schekman not identify all genes involved in the secretory pathway?
- only identified temperature sensitive mutants, and you can’t get a temp sensitive mutation out of everything
- only secretion to the PM was observed, (may be different proteins involved in trafficking to endosome/vacuoles
- any redundantly functioning genes (where one gene covers/does same role as other gene) were not identified
- genes where deletion caused death of organism not identified?
how do secretory mutants ultrastructure differ to normal cells?
- are dense - have lots of vesicles
- BERKLEY BODIES (defective endosomal structure)
how were cells analysed?
they were analysed by electron microscopy (could see accumulation of vesicles)
what could sensory mutants fail to secrete?
mutants failed to secrete invertase and acid phosphatase under restrictive growth conditions
how were temperature sensitive mutants for secretion identified?
I cell had mutant for secretion the cell was dense and non-permissive temperatures (temperature where mutation is observable)
what are permissive temperatures?
temperatures where a mutant elicts the same repsonse as WT (no mutant phenotype)
what were the main findings from nocik and schekmans experiemnt?
- showed secretory protein moves from cytoplasm to ER, to golgi, secretory vesicles, then the PM
- also identified 23 sec genes
