Application of the COPAS (Complex Object Parametric Analysis and Sorting) dispenser to functional genomic studies.

The completion of the C.elegans genome sequence has facilitated the identification of most genes at the sequence level. This genomic data can be used to investigate how physiology and development are regulated globally . Investigators rely on the development of functional genomic tools that aid quicker identification of gene function after sequence discovery. One emerging technology in the area of functional genomics is the development of a unique sorter/dispenser for C.elegans available from Union Biometrica Incorporated, Somerville, MA, USA. The COPAS (complex object parametric analysis and sorting) dispenser is capable of sorting a heterogeneous population of worms based on size (developmental stage), shape (phenotype, based on density by signal extinction), or fluorescent properties (GFP reporter expression, for example). Funding to obtain a COPAS machine for our laboratory has been provided by the Wellcome Trust. Our facility will be made available as a resource to the UK C.elegans research community. The COPAS worm sorter has many applications relevant to functional genomic studies. These include; 1. The production of highly enriched, specifically staged worms. Accurately staged worms can be used for expression studies using Northern blots, RT-PCR or DNA microarray profiling. 2. The ability to detect fluorescent signals. It is possible to sort animals expressing (or mis-expressing) a fluorescent reporter, even if the reporter is only expressed during a narrow period of development. 3. The production of highly enriched single sex populations using GFP reporters in embryos and young larvae or light extinction properties in adults. 4. Dispensing of individual nematodes after mutagenesis into microtitre wells to facilitate large scale clonal screening and to generate a deletional mutagenesis library. Thus it is now conceivable to screen tens of thousands of worms with the hope of approaching mutational saturation for specific traits. In addition to the uses described above our laboratory is taking advantage of the COPAS dispenser to generate GFP labelled genetic balancers and chromosomes. The examples above have been provided to illustrate the utility of the worm flow sorter; it is anticipated that innovative uses for the device will be developed by individual researchers to address their particular experimental needs.