Description
Caenorhabditis elegans is a free-living nematode (one of the roundworms), about 1 mm in length, and lives in a temperate soil environment. Members of the species have many of the same organ systems as other animals including humans. C. elegans is used as a model organism in research. Specimens are cheap and easy to maintain in the laboratory. C. elegans has been especially useful for studying cellular differentiation, and was the first multicellular organism to have its genome completely sequenced. The finished genome sequence was published in 1998, is approximately 100 million base pairs long and contains more than 20,000 genes.
From a research perspective, C. elegans has the advantage of being a multicellular eukaryotic organism which is simple enough to be studied in great detail. Being transparent, the internal structures can be seen during all stages of development, which has allowed the mapping of the developmental fate of every single somatic cell (about 1000). These patterns of cell lineage are largely invariant between individuals, in contrast to mammals where cell development from the embryo is more dependent on cellular cues.
In addition, C. elegans is one of the simplest organisms with a relatively complex nervous system. In the hermaphrodite, this comprises 302 neurons whose pattern of connectivity has been completely mapped, and proven to be a small-world network. Research has explored the neuronal mechanisms responsible for several of C. elegans' more interesting behaviors, including chemotaxis, thermotaxis, mechanotransduction, and male mating behavior. Interestingly, the neurons fire no action potentials.
In 2002, the Nobel Prize for Physiology and Medicine was awarded to Sydney Brenner, H. Robert Horvitz and John Sulston for their work on the genetics of organ development and programmed cell death in C. elegans. In 2006, the Nobel Prize for Physiology and Medicine was awarded to Andrew Fire and Craig Mello for their discovery of RNA interference and gene silencing by double-stranded RNA in C. elegans. In 2008, the Nobel Prize for Chemistry was awarded to the C. elegans researcher Martin Chalfie and to two other researchers for their discovery and development of the green fluorescent protein (GFP).
Infrastructure/methods
The observation that a large number of genes is conserved between humans and the worm (among them many disease-related genes) has enticed the scientific community to further explore the possibilities of C. elegans as a model organism to study novel genes. In this context, RNA-mediated interference (RNAi), a phenomenon extensively used as a tool in C. elegans research to remove the function of a targeted gene, as well as the straightforward mutation of genes, are crucial applications in the study of the function of novel genes. Other “highlight” methods and techniques include the facile construction of transgenic worm lines, live light and fluorescence microscopy, functional genomics and bioinformatics applications, and automated (FACS-like) live worm-sorting for large-scale screens.
In Peter Swoboda’s laboratory they focus on neurobiology and developmental biology, with specific interests in the development of sensory structures and behaviours, as well as in neuronal physiology and its impact on nervous system function and aging. RNAi, gene mutations, GFP expression, antibody staining, behavioural assays are used to study gene function.
In Thomas Bürglin’s laboratory the main focus is on developmental biology and neurobiology, and especially on how cell fate and cell differentiation is regulated. Advanced 4D microscopy has been developed to monitor live gene expression. RNAi, gene-knock-outs, GFP expression, antibody staining, behavioural assays are used to study gene function.
Practical information
Please check our research group web sites and contact us for any further information.
www.bionut.ki.se/groups/psw/ and
www.biosci.ki.se/groups/tbu/index.html