Making Sense of G Proteins: Genetic analysis of sensory G protein signaling in the nematode C. elegans

Among the key molecules involved in sensory perception are G proteins, which act in every cell to activate a cascade of signaling molecules in response to certain environmental cues. In this thesis, several studies on the role of G proteins in the sensory system of C. elegans are described. First, in Chapter 1, a brief overview of the biology of C. elegans and of G protein signaling in general and in C. elegans is presented. Next, in Chapter 2, the sensory system of C. elegans is discussed in more (molecular) detail. In Chapter 3, the impact of sensory signaling on the regulation of dauer formation and longevity is discussed. Chapter 4 deals with the role of G protein signaling in the detection of attractive odorants by C. elegans. Data is presented which indicate that olfaction in C. elegans is regulated by a complex signaling network involving five G proteins. In Chapter 5, the regulation of olfactory receptor gene expression by G proteins is described. B! oth cell autonomous as well as non-cell autonomous G protein signals regulate str-2 receptor gene expression, in cooperation with Ca2+/MAPK signaling molecules. Chapter 6 shows that G protein signaling in the sensory neurons also modulates longevity in C. elegans. Finally, in Chapter 7, future directions are provided.