Presentation on theme: "Lecture 9 C. elegans cell biology C. elegans genetics C. elegans genome."— Presentation transcript:
Lecture 9 C. elegans cell biology C. elegans genetics C. elegans genome
Theoretically perfect model organism Well characterized life cycle-all stages easily accessible. Well characterized genetic system. Well characterized genome-basically sequenced and annotated. The ability to reintroduce DNA into the organism-transgenesis. Closely related to humans-funding purposes.
Caenorabditis elegans Life cycle: short 3 1/2 days, transparent organism, complete cell lineage known. Genetic system: both classical and RNAi Genome: first metazoan sequenced 1998 Transgenesis: injection of DNA Related to humans?
Caenorabditis elegans Hermaphrodite Horvitz and Sternberg Nature 351, 535
Hermaphrodite and male Wood 1998 The Nematode C. elegans
Cross section tube within a tube Wood 1998 The Nematode C. elegans
Equivalence groups: Group of cells that have equivalent pluripotent cell fates.
Z1.ppp Z4.aaa Individual AIndividual B Anchor cell/ Ventral uterine cell equivalence group AC VU
Z1.ppp Z4.aaa Experiment AExperiment B Anchor cell/ Ventral uterine cell equivalence group AC Cell ablation experiment
Z1.ppp Z4.aaa Experiment AExperiment B Anchor cell/ Ventral uterine cell equivalence group AC Cell ablation experiment The remaining cell always becomes an AC. The AC fate is the 1° (primary) cell fate.
RNAi inhibition of gene expression 1. RNAi discovered in C. elegans and plants. 2. Double stranded RNA results in the degradation of homologous mRNA. 3. Double stranded RNA can be fed to worms in the E. coli they eat. 4. Allows for the systematic inhibition of all 20,000 genes of C. elegans.
Systematic RNAi screens in C. elegans Tuschl Nature 421, 220