European Chronobiology School edition:17 location:Laulasmaa (Estonia) date:7-14 June 2008
Caenorhabditis elegans has a circadian clock that regulates the nematode’s activity and resistance to hyperosmotic stress with a mechanism yet to be unravelled (1). Circadian rhythms and their genetic backgrounds have been studied thoroughly in Drosophila melanogaster. A certain neuropeptide, named PDF, plays an important role in the output of the endogenous clock and in the synchronisation of the individual pacemaker neurons (2). We recently identified three PDF-like peptides and their corresponding G protein-coupled receptors in C. elegans (3). Since other clock gene homologues as lin-42 (homologue of period), tim-1 (homologue of timeless) and kin-20 (homologue of doubletime) seem to have a function in developmental timing rather than in circadian timing (4), we try to disentangle the molecular basis of this nematode’s clock with PDF as our major lead. In vivo localisation of the PDF neuropeptides and their receptors points to a function in the regulation of locomotory behaviour. We also consider the possibility of PDF involvement in mechanosensation, the basal- and enhanced slowing response to food, chemosensation and geotactic behaviour. For this purpose, we conduct physiological experiments as well as qRT-PCR to follow up the expression of specific genes. Microarray and proteomics experiments are conducted to discover new elements in the PDF signalling pathway.